首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3512篇
  免费   140篇
  国内免费   29篇
耳鼻咽喉   89篇
儿科学   240篇
妇产科学   197篇
基础医学   279篇
口腔科学   194篇
临床医学   227篇
内科学   635篇
皮肤病学   82篇
神经病学   279篇
特种医学   107篇
外科学   909篇
综合类   30篇
一般理论   3篇
预防医学   56篇
眼科学   85篇
药学   119篇
肿瘤学   150篇
  2024年   3篇
  2023年   35篇
  2022年   72篇
  2021年   123篇
  2020年   88篇
  2019年   93篇
  2018年   117篇
  2017年   101篇
  2016年   130篇
  2015年   164篇
  2014年   154篇
  2013年   181篇
  2012年   258篇
  2011年   271篇
  2010年   143篇
  2009年   131篇
  2008年   234篇
  2007年   245篇
  2006年   238篇
  2005年   242篇
  2004年   196篇
  2003年   124篇
  2002年   120篇
  2001年   39篇
  2000年   36篇
  1999年   34篇
  1998年   11篇
  1997年   11篇
  1996年   6篇
  1995年   16篇
  1994年   3篇
  1993年   5篇
  1992年   10篇
  1991年   4篇
  1990年   5篇
  1989年   3篇
  1988年   9篇
  1987年   7篇
  1986年   4篇
  1985年   3篇
  1984年   4篇
  1983年   1篇
  1980年   1篇
  1978年   2篇
  1977年   1篇
  1975年   1篇
  1970年   1篇
  1909年   1篇
排序方式: 共有3681条查询结果,搜索用时 15 毫秒
21.
Antisynthetase syndrome (ASS) is characterized by inflammatory muscle disease, pulmonary and joint involvement, and antisynthetase autoantibodies, with anti‐Jo‐1 antibody being the most common. Despite the use of immunosuppressive drugs, the prognosis of lung involvement seems poor. Herein, we report a case of refractory ASS, which maintained long‐term remission by double filtration plasmapheresis (DFPP) combined with immunosuppressive therapy. For a 65‐year‐old woman, who was diagnosed with ASS, immunosuppressive therapy was initiated and plasmapheresis (PP) was performed five times due to acute interstitial pulmonary disease and inflammatory myopathy. She remained in remission for eight months following PP. Increase in interstitial involvement was identified by lung tomography when the patient presented again with complaint of progressive increase in dyspnea and muscle pain. Although the immunosuppressive therapy was increased for the patient with elevated creatine phosphokinase (CPK) (2776 IU/mL), a rapid decrease in diffusion capacity of the lung for carbon monoxide (DLCO) was observed and the patient underwent PP. After four sessions of therapy, insufficient clinical and laboratory response was obtained (control CPK 1797 IU/mL) and because of that issue DFPP using a 2A filter was performed to the patient. There was a marked improvement in complaints of the patient, DLCO, and laboratory findings (control CPK 508 IU/mL) after three sessions of DFPP. The patient, who continued the immunosuppressive therapy after DFPP procedure, is being followed for 12 months in remission. Although our experience is limited with only one patient, DFPP seems promising as a treatment option for ASS with severe lung involvement. J. Clin. Apheresis, 28:422–425, 2013. © 2013 Wiley Periodicals, Inc.  相似文献   
22.
OBJECTIVE: To investigate the relationship between peripheral and central venous pressures in different patient positions (supine, prone, lithotomy, Trendelenburg, and Fowler), different catheter diameters (18 G and 20 G), and catheterization sites (dorsal hand and forearm) during surgical procedures. DESIGN: Prospective clinical study. SETTINGS: University hospital. PARTICIPANTS: Five hundred adult patients. INTERVENTIONS: Peripheral over-the-needle intravenous catheters were placed in the dorsal hand or forearm. Central venous catheters were inserted via the internal jugular or subclavian vein after induction of anesthesia. MEASUREMENTS and MAIN RESULTS: Simultaneous measurements of central and peripheral venous pressures were made during stable conditions at random time points in surgery; 1953 paired measurements were performed. Mean central venous pressure was 11 +/- 3.7 mmHg and peripheral venous pressure was 13 +/- 4 mmHg (p = 0.0001). The overall correlation between central venous and peripheral venous pressures was found to be statistically significant (r = 0.89, r(2) = 0.8, p = 0.0001). Mean difference between peripheral and central venous pressure was 2 +/- 1.8 mmHg. Ninety-five percent limits of agreement were 5.6 to -1.6 mmHg. CONCLUSION: It has been assumed that replacing central venous pressure by peripheral venous pressure would cause problems in clinical interpretation. If the validity of this data is confirmed by further studies, the authors suggest that central venous pressure could be estimated by using regression equations to compare the 2 methods.  相似文献   
23.
OBJECTIVE: The analgesic effect of bupivacaine/fentanyl with epinephrine given interpleurally after thoracotomy was investigated in a randomized placebo and intravenous controlled study. DESIGN: Prospective clinical study. SETTING: University teaching hospital. PARTICIPANTS: Sixty American Society of Anesthesiologists physical status II and III patients scheduled for posterolateral thoracotomy with general anesthesia. INTERVENTIONS: Patients were randomly divided into 4 groups to receive either 0.5% bupivacaine/1.5 microg/kg of fentanyl with 5 microg/mL of epinephrine (n = 15, group IPBF), 0.5 % bupivacaine with 5 microg/mL of epinephrine (n = 15, group IPB), or saline (n = 15, group IPS) in a total volume of 15 to 20 mL in 60 seconds by an interpleural catheter placed at the end of surgery by direct vision. The same volume of bupivacaine 0.25% and 1.5 microg/kg of fentanyl with 5 microg/mL of epinephrine to group IPBF, bupivacaine 0.25% with 5 microg/mL of epinephrine to group IPB or saline to group IPS was injected through the interpleural catheter every 6 hours for 48 hours postoperatively. Intravenous fentanyl (n = 15, group IVF) and interpleural saline groups received 1.5 microg/kg of fentanyl intravenously at the first complaint of pain. All patients also received patient-controlled analgesia (PCA) with fentanyl for 48 hours postoperatively. Metamizol sodium was used as a rescue analgesic. MEASUREMENTS and MAIN RESULTS: Adequacy of pain relief was evaluated with the "Prince Henry Pain Scale" and visual analog pain scale. Fentanyl consumption via PCA and complications were evaluated for 48 hours. Visual analog scale scores were significantly higher in the interpleural saline group at 4 and 12 hours (6.6 +/- 1.2 and 5.0 +/- 2.1, respectively) postoperatively. Significantly more patients in the IPBF group had lower pain scores during coughing and deep breathing. Fentanyl consumption via PCA device was significantly higher in the intravenous fentanyl group (1,069 +/- 96.9 microg) than the interpleural groups (577.3 +/- 72.2 microg, 651.1 +/- 61.9 microg, and 601.0 +/- 22.6 microg in IPBF, IPB, and IPS groups, respectively). CONCLUSION: It is concluded that total fentanyl consumption via PCA decreased in all interpleural groups, but pain during coughing and deep breathing was significantly reduced in only the interpleural bupivacaine/fentanyl with epinephrine group.  相似文献   
24.
BACKGROUND: Laparoscopic cholecystectomy (LC) has replaced open cholecystectomy for the treatment of gallbladder disease. Despite the well-accepted success of LC in chronic cholecystitis, the efficacy of this technique has been subject to some debate in acute cholecystitis (AC). This study was designed to evaluate our institution's experience with LC for AC and chronic symptomatic calculous cholecystitis (CC), based on complication and conversion rates to open surgery. PATIENTS AND METHODS: The records of 1158 patients with LC from September 1991 to December 2001 were analyzed. The parameters of age, gender, early and late complication rates, and conversion rates from LC to open cholecystectomy were compared in patients with AC and CC. RESULTS: During the study period, LC was performed in 1158 patients. Of these, 162 patients had AC (group 1) and 996 patients had CC (group 2). The conversion rates were 4.3% (7/162) in group 1 and 2.4% (24/996) in group 2. The complication rates were not significantly different (5.6% in group 1, 5.1% in group 2, P > 0.05). Difficulty in dissection around Calot's triangle and obscure anatomy were the main reasons for conversion to conventional open surgery. The mortality rate was 1.2% in group 1 and 0.01% in group 2. CONCLUSION: LC appears to be a reliable, safe, and effective treatment modality for AC and CC. The surgical approach should be performed carefully because of the spectrum of potential hazards of the laparoscopic procedure. Conversion and complication rates are similar in both AC and CC groups, and improve as surgeons gain experience.  相似文献   
25.
OBJECTIVES: To compare WHO 1973, WHO/ISUP 1998 and WHO 1999 histologic grading systems, and also to evaluate the primary (most common) and secondary (second most common) patterns of cancer growth according to these three grading systems. MATERIAL AND METHODS: The study consisted of 87 bladder transurethral resections that were classified as grade 1, 2 and 3, and papillary urothelial neoplasm of low malignant potential (PUNLMP), low grade (LG) and high grade (HG) carcinoma considering WHO 1973 and WHO/ISUP, respectively. The WHO 1999 system was subdivided high grade into grades 2 and 3 (HG-2 and HG-3). For combined scoring, primary (most common) and secondary (second most common) grades according to extension were recorded for three grading systems. The number was repeated when only grade was seen in all extension of the tissue examined. A final combined score was obtained which ranged from 2 to 6 for the WHO 1973 and WHO/ISUP 1998 systems and from 2 to 8 for the WHO 1999 schema. The TNM system was used for the pathologic staging. RESULTS: When considering the pathological stage, there were statistical differences between the WHO 1973 grades (p=0.011 and p=0.000), and LG and HG carcinomas of WHO/ISUP 1998 (p=0.000) and also the WHO 1999 grades (p=0.010 and p=0.003), except PUNLMP. Regarding the combined scoring, significant differences were found between score 4 (2+2) and 5 (2+3) of WHO 1973 (p=0.014) and score 5 (LG+HG) and 6 (HG+HG) of WHO/ISUP 1998 (p=0.011). There was also a significant difference between scores 4 and 6, and 6 and 8 of the WHO 1999 combined scoring system (p=0.019 and p=0.019). WHO 1973, WHO/ISUP 1998 and WHO 1999 systems were positively correlated with the pathological stage (r(s)=0.30, r(s)=0.52 and r(s)=0.50, respectively), whereas there was weak association between the combined scoring systems and stage (r(s)=0.20, r(s)=0.18 and r(s)=0.19). Comparing these grading systems, the grade 2 of WHO 1973 was subdivided into LG and HG in WHO/ISUP 1998 and also LG-1and HG-2 in WHO 1999 systems. The group of HG carcinoma in WHO/ISUP 1998 which was subdivided into HG-2 and HG-3 in the WHO 1999 system was different statistically in relation to the stage. CONCLUSIONS: Our results revealed that the WHO 1999 system may be more useful to evaluate the bladder carcinoma histopathologically in comparison to the WHO 1973 and WHO/ISUP 1998 systems.  相似文献   
26.
Little information exists regarding the efficacy, modifiers, and outcomes of anemia management in children with CKD or ESRD. We assessed practices, effectors, and outcomes of anemia management in 1394 pediatric patients undergoing peritoneal dialysis (PD) who were prospectively followed in 30 countries. We noted that 25% of patients had hemoglobin levels below target (<10 g/dl or <9.5 g/dl in children older or younger than 2 years, respectively), with significant regional variation; levels were highest in North America and Europe and lowest in Asia and Turkey. Low hemoglobin levels were associated with low urine output, low serum albumin, high parathyroid hormone, high ferritin, and the use of bioincompatible PD fluid. Erythropoiesis-stimulating agents (ESAs) were prescribed to 92% of patients, and neither the type of ESA nor the dosing interval appeared to affect efficacy. The weekly ESA dose inversely correlated with age when scaled to weight but did not correlate with age when normalized to body surface area. ESA sensitivity was positively associated with residual diuresis and serum albumin and inversely associated with serum parathyroid hormone and ferritin. The prevalence of hypertension and left ventricular hypertrophy increased with the degree of anemia. Patient survival was positively associated with achieved hemoglobin and serum albumin and was inversely associated with ESA dose. In conclusion, control of anemia in children receiving long-term PD varies by region. ESA requirements are independent of age when dose is scaled to body surface area, and ESA resistance is associated with inflammation, fluid retention, and hyperparathyroidism. Anemia and high ESA dose requirements independently predict mortality.Almost three decades after the advent of recombinant erythropoietin, the management of renal anemia has become a recent focus of attention and changing paradigms. Whereas correction of hemoglobin (Hb) levels to near-normal has previously been recommended on the basis of association studies linking more severe anemia to morbidity and mortality with dialysis,13 interventional clinical trials consistently demonstrate that near-normalization of Hb increases the risk of vascular events and mortality in adults receiving maintenance hemodialysis and in those with CKD who are not undergoing dialysis.46 This has prompted ongoing reevaluation and revisions of treatment targets in patients exposed to erythropoiesis-stimulating agents (ESAs).7The appropriateness of applying treatment recommendations established in adult hemodialysis populations at high cardiovascular risk and adults with CKD to children undergoing dialysis is questionable because cardiovascular events are far less common in children with CKD. Furthermore, two thirds of children requiring dialysis initially opt for peritoneal dialysis (PD), and there are no systematic studies in the adult PD population to inform the optimal Hb target range in these patients. The risk profile of patients receiving PD may differ from that of the hemodialysis setting because of the absence of dialysis-induced intermittent hemoconcentration and lack of contact activation of the complement and coagulation systems.Further aspects to consider in pediatric anemia management are the greater physical activity of children and the need for optimal cognitive functioning at school.8,9 The significant physiologic variation of the normal Hb range with age10 and the relative ESA sensitivity that reportedly increases with age during early childhood are also noteworthy.11The registry of the International Pediatric Peritoneal Dialysis Network (IPPN) prospectively collects detailed clinical, biochemical, dialysis, and medication-related information (including ESA types and doses and modalities of iron supplementation) from a substantial number of children undergoing long-term PD around the world. In-depth analysis of this unique database has allowed us to (1) gain insight into the demographic characteristics of renal anemia and its treatment in the pediatric PD population worldwide, (2) explore the relationship between ESA dose requirements and body dimensions, (3) identify factors contributing to ESA resistance in children, and (4) associate anemia control with patient outcomes.  相似文献   
27.

Background

The purpose of this study is to investigate the inter- and intraobserver reliability of Crowe and Hartofilakidis classifications in the assessment of developmental dysplasia of the hip in adult patients.

Materials and methods

Two consultant orthopedic surgeons classified 141 dysplastic hips on 103 standard anterior–posterior pelvis radiographs according to the Crowe and Hartofilakidis classifications. Assessments were performed in random order by each observer on two separate occasions, at least 4?weeks apart. Kappa statistics were used to establish a relative level of agreement between observers for the two readings and between separate readings by the same observer.

Results

At the first readings, interobserver reliability analysis revealed kappa coefficient of 0.71 for the Crowe classification and 0.54 for the Hartofilakidis classification. At the second reading, the kappa coefficient was 0.72 for the Crowe classification and 0.75 for the Hartofilakidis classification. Intraobserver reliability analysis revealed kappa coefficients of 0.71 for the Crowe and 0.80 for the Hartofilakidis classification for observer A, and 0.76 and 0.70 for observer B.

Conclusions

In conclusion, we have found substantial inter- and intraobserver agreement for Crowe classification and substantial to moderate agreement for Hartofilakidis classification in this study. Both classification systems assess the different aspects of developmental dysplasia of hip in adults. Each system has advantages and disadvantages. We suggest using both of these classifications together to increase the accuracy.  相似文献   
28.
There are many different lower eyelid reconstruction techniques defined in the literature. Almost all of the published techniques have been described on elderly patients and use upper eyelid, periorbital or facial tissues as donor sites. However, in case of a paediatric patient or a young adult who has a crease-free and scarless face, camouflage of the facial donor-site scar is usually impossible. In order to avoid possible facial donor-site scars and upper eyelid deformities, a technique which uses the temporoparietal fascia (TPF) flap as the framework of a new eyelid was used for the reconstruction of an adolescent patient's postoncologic defect. The inner side of the flap was covered with nasal septal chondromucosal graft and the external side was covered with a retroauricular full-thickness skin graft. Eighteen months of unproblematic follow-up of this overlooked usage of the versatile TPF flap indicates that our technique has proved successful in terms of good functional and cosmetic outcome that is obtained at one stage.  相似文献   
29.
BACKGROUND: Mesenteric ischemia-reperfusion (I/R) is a well-known event causing both local and remote organ injuries, including the lungs. Recently, several studies indicated that activated leukocyte-endothelial cell interactions play an important role in the mechanisms of these injuries. As a natural inhibitor of serine proteases, antithrombin was shown previously to attenuate the tissue damage after local I/R in several organ systems. Here, we examined the effects of antithrombin on pulmonary injury after mesenteric I/R. METHODS: Wistar albino rats underwent median laparotomy and were randomized into 3 groups: (1) sham-operated control (n = 12), (2) 60 minutes of mesenteric ischemia and 3 hours of reperfusion (n = 12), and (3) antithrombin-pretreated (250 U/kg) group before the I/R (n = 12). At the end of reperfusion, animals were killed and neutrophil sequestration, myeloperoxidase (MPO) activity, and Evans blue dye extravasation in the lung parenchyma were assessed and compared. RESULTS: There was a statistically significant increase in the quantity of Evans blue dye concentration, leukocyte sequestration, and MPO activity in the I/R group when compared with the control group. The pretreatment of animals with antithrombin significantly decreased the pulmonary injury characterized by increased Evans blue dye extravasation, leukocyte sequestration, and MPO activity. CONCLUSION: The data of the present study suggest that mesenteric ischemia and reperfusion induces pulmonary injury characterized by activated neutrophil sequestration and increased microvascular leakage in the lungs. A significant attenuation of intestinal I/R-related lung injury with the use of antithrombin concentrate warrants further studies to elucidate the potential role of this natural serine protease inhibitor in clinical settings.  相似文献   
30.
OBJECTIVES: The purpose of this study was to investigate the effects of PEEP on oxygenation and airway pressures during PCV-OLV. DESIGN: Randomized, crossover, clinical study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing thoracotomy. INTERVENTIONS: During the first 5 minutes of OLV, all patients were ventilated with VCV (PEEP: 0) (VCV-ZEEP). Afterward, ventilation was changed to PCV with PEEP: 0 (PCV-ZEEP) or PEEP: 4 cmH2O (PCV-PEEP) for 20 minutes. In the following 20 minutes, PCV-PEEP and PCV-ZEEP were applied in reverse sequence. MEASUREMENTS AND MAIN RESULTS: At the end of VCV-ZEEP airway pressures (peak airway pressure, plateau airway pressure, mean airway pressure, and pause airway pressure) were recorded. At the end of PCV-PEEP and PCV-ZEEP airway pressures, PaO2 and Qs/Qt were recorded. Ppeak and Pplat were significantly lower with PCV-PEEP compared with VCV-ZEEP (eg, Ppeak: 33.4+/-4.2, 28.3+/-4.1, and 28.9+/-3.7 cmH2O in VCV-ZEEP, PCV-ZEEP, and PCV-PEEP, respectively; p<0.05 for PCV-ZEEP v VCV-ZEEP and PCV-PEEP v VCV-ZEEP). PCV-PEEP was associated with an increased PaO2 (230.3+/-69.8 v 189.0+/-54.8 mmHg, p<0.05) and decreased Qs/Qt (33.4%+/-7.3% v 38.4%+/-5.7%, p<0.05) compared with PCV-ZEEP (mean+/-SD). Eighty-eight percent of the patients have benefited from PEEP. CONCLUSION: During OLV, PCV with a low level of PEEP leads to improved oxygenation with lower airway pressures.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号