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   162095篇
  免费   8664篇
  国内免费   569篇
耳鼻咽喉   1797篇
儿科学   3926篇
妇产科学   2616篇
基础医学   21004篇
口腔科学   3434篇
临床医学   15680篇
内科学   33932篇
皮肤病学   3273篇
神经病学   14779篇
特种医学   7002篇
外国民族医学   14篇
外科学   25307篇
综合类   1958篇
一般理论   109篇
预防医学   11888篇
眼科学   3333篇
药学   10173篇
  7篇
中国医学   238篇
肿瘤学   10858篇
  2024年   653篇
  2023年   953篇
  2022年   1518篇
  2021年   3466篇
  2020年   2213篇
  2019年   3273篇
  2018年   3607篇
  2017年   2809篇
  2016年   3140篇
  2015年   3591篇
  2014年   5098篇
  2013年   6859篇
  2012年   10345篇
  2011年   11015篇
  2010年   6313篇
  2009年   6016篇
  2008年   9747篇
  2007年   10189篇
  2006年   10098篇
  2005年   10144篇
  2004年   9307篇
  2003年   8619篇
  2002年   8271篇
  2001年   2153篇
  2000年   1846篇
  1999年   2132篇
  1998年   1925篇
  1997年   1552篇
  1996年   1334篇
  1995年   1251篇
  1994年   1125篇
  1993年   1015篇
  1992年   1293篇
  1991年   1191篇
  1990年   1036篇
  1989年   973篇
  1988年   911篇
  1987年   884篇
  1986年   883篇
  1985年   865篇
  1984年   924篇
  1983年   795篇
  1982年   960篇
  1981年   860篇
  1980年   728篇
  1979年   654篇
  1978年   646篇
  1977年   533篇
  1976年   514篇
  1974年   511篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
951.
Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? Thus far, no institution has investigated the impact of the most commonly used surgical techniques – open, laparoscopic and robotic radical prostatectomy – on biochemical outcome. However, recent data from large meta‐analysis suggest that the impact of the chosen surgical technique on biochemical outcome is minimal and statistically not relevant. We are the first to apply the method of propensity score matching in the urology literature to compare three different surgical techniques. This method is intended to simulate a randomized trial which is unlikely to be undertaken for radical prostatectomies. We confirmed previous data that the surgical technique does not seem to have an impact on biochemical outcome following radical prostatectomy.

OBJECTIVE

? To investigate a single institution experience with radical retropubic prostatectomy (RRP), laparoscopic radical prostatectomy (LRP) and robot‐assisted radical prostatectomy (RARP) with respect to pathological and biochemical outcomes.

PATIENTS AND METHODS

? A group of 522 consecutive patients who underwent RARP between 2003 and 2008 were matched by propensity scoring on the basis of patient age, race, preoperative prostate‐specific antigen (PSA), biopsy Gleason score and clinical stage with an equal number of patients who underwent LRP and RRP at our institution. ? Pathological and biochemical outcomes of the three cohorts were examined.

RESULTS

? Overall positive surgical margin rates were lower among patients who underwent RRP (14.4%) and LRP (13.0%) compared to patients who underwent RARP (19.5%) (P= 0.010). There were no statistically significant differences in positive margin rates between the three surgical techniques for pT2 disease (P= 0.264). ? In multivariate logistic regression analysis, surgical technique (P= 0.016), biopsy Gleason score (P < 0.001) and preoperative PSA (P < 0.001) were predictors of positive surgical margins. ? Kaplan–Meier analysis did not show any statistically significant differences with respect to biochemical recurrence for the three surgical groups.

CONCLUSIONS

? RRP, LRP and RARP represent effective surgical approaches for the treatment for clinically localized prostate cancer. A higher overall positive SM rate was observed for the RARP group compared to RRP and LRP; however, there was no difference with respect to biochemical recurrence‐free survival between groups. ? Further prospective studies are warranted to determine whether any particular technique is superior with regard to long‐term clinical outcomes.  相似文献   
952.
The ability to compare intensive care units (ICUs) and determine whether they provide the same level of care with regard to efficacy, efficiency, and quality is a cornerstone of understanding critical care and improving the quality of that care. Without collecting high-quality data, adjusted for severity of illness and analyzed in a comparative fashion, it would not be possible to describe best practices objectively, to identify which ICUs are doing a good job or to learn from those units that are. This review article discusses how and why ICUs are compared. Particular attention is focused on the severity of illness scores, standardized mortality, and comparative reporting. A data collecting network, Virtual Pediatric Systems, limited liability corporation (VPS, LLC), designed for the purposes of determining where differences in critical care can be identified and the value that this adds in improving quality is discussed. Finally, results from this large data sharing collaborative describing the practice of pediatric critical care are included for the purpose of pediatric intensive care units practice benchmarks.  相似文献   
953.
BACKGROUND: To counsel patients adequately, it is important to understand the variables influencing satisfaction and regret following prostatectomy. OBJECTIVE: To identify independent predictors for satisfaction and regret after radical prostatectomy. DESIGN, SETTING, AND PARTICIPANTS: Patients who had undergone retropubic radical prostatectomy (RRP) or robot-assisted laparoscopic radical prostatectomy (RALP) between 2000 and 2007 were mailed cross-sectional surveys composed of sociodemographic information, the Expanded Prostate Cancer Index Composite (EPIC), and questions regarding satisfaction and regret. MEASUREMENTS: Sociodemographic variables, perioperative complications, type of procedure, length of follow-up, and EPIC scores were evaluated as independent predictors of satisfaction and regret in multivariate logistic regression analysis. RESULTS AND LIMITATIONS: A total of 400 patients responded (response rate 61%) of whom 84% were satisfied and 19% regretted their treatment choice. In multivariate analysis, lower income (odds ratio [OR], 0.08; 95% confidence interval [CI], 0.03-0.23), shorter follow-up (OR, 0.63; 95% CI, 0.41-0.98), having undergone RRP versus RALP (OR, 4.45; 95% CI, 1.90-10.4)], urinary domain scores (OR, 2.70; 95% CI, 1.60-4.54), and hormonal domain scores (OR, 2.01; 95% CI, 1.30-3.12) were independently associated with satisfaction (p相似文献   
954.
OBJECTIVES: Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the temporal cortex has been proposed as a new treatment strategy for patients with chronic tinnitus. However, functional abnormalities in tinnitus patients also involve brain structures used for attentional and emotional processing, such as the dorsolateral prefrontal cortex. Therefore, we have developed a new rTMS treatment strategy for tinnitus patients that consists of a combination of high-frequency prefrontal and low-frequency temporal rTMS. STUDY DESIGN: A total of 32 patients received either low-frequency temporal rTMS or a combination of high-frequency prefrontal and low-frequency temporal rTMS. Treatment effects were assessed with a standardized tinnitus questionnaire (TQ). RESULTS: Directly after therapy there was an improvement of the TQ-score for both groups, but no differences between groups. An evaluation after 3 months revealed a remarkable benefit from the use of combined prefrontal and temporal rTMS treatment. CONCLUSION: These results support recent data that suggest that auditory and nonauditory brain areas are involved in tinnitus pathophysiology.  相似文献   
955.
BACKGROUND: Follow-up mortality is high in patients with type B aortic dissection (TB-AD) approaching one in four patients at 3 years. A predictor of increased mortality is partial thrombosis of the false lumen which may occlude distal tears. The hemodynamic consequences of differing tear size, location, and patency within the false lumen is largely unknown. We examined the impact of intimal tear size, tear number, and location on false lumen pressure. METHODS: In an ex-vivo model of chronic type B aortic dissection connected to a pulsatile pump, simultaneous pressures were measured within the true and false lumen. Experiments were performed in different dissection models with tear sizes of 6.4 mm and 3.2 mm in the following configurations; model A: proximal and distal tear simulating the most common hemodynamic state in patients with TB-AD; model B: proximal tear only simulating patients with partial thrombosis and occlusion of distal tear; and model C: distal tear only simulating patients sealed proximally via a stent graft with persistent distal communication. To compare false lumen diastolic pressure between models, a false lumen pressure index (FPI%) was calculated for all simulations as FPI% = (false lumen diastolic pressure/true lumen diastolic pressure) x 100. RESULTS: In model A, the systolic pressure was slightly lower in the false lumen compared with the true lumen while the diastolic pressure (DP) was slightly higher in the false lumen (DP 66.45 +/- 0.16 mm Hg vs 66.20 +/- 0.12 mm Hg, P < .001, FPI% = 100.4%). In the absence of a distal tear (model B), diastolic pressure was elevated within the false lumen compared with the true lumen (58.95 +/- 0.10 vs 54.66 +/- 0.17, P < .001, FPI% = 107.9%). The absence of a proximal tear in the presence of a distal tear (model C) diastolic pressure was also elevated within the false lumen versus the true lumen (58.72 +/- 0.24 vs 56.15 +/- 0.16, P < .001, FPI% 104.6%). The difference in diastolic pressure was greatest with a smaller tear (3.2 mm) in model B. In model B, DBP increased by 13.9% (P < .001, R(2) 0.69) per 10 beat per minute increase in heart rate (P < .001) independent of systolic pressure. CONCLUSIONS: In this model of chronic type B aortic dissection, diastolic false lumen pressure was the highest in the setting of smaller proximal tear size and the lack of a distal tear. These determinants of inflow and outflow may impact false lumen expansion and rupture during the follow-up period.  相似文献   
956.
Sixty-six feet (62 patients) with displaced intra-articular calcaneal fractures underwent manual reduction and distraction with the use of a triangular tube-to-bar external fixation device and were retrospectively reviewed at a minimum of 1-year post-operative. Final radiographic follow-up revealed complete consolidation in all fractures, maintenance of reduction, and limited degenerative osteoarthrosis about the subtalar joint. Our results indicate that with proper application and attention to detail, restoration of calcaneal morphology using triangular tube-to-bar external fixation should be considered a viable alternative in the treatment of displaced intra-articular fractures of the calcaneus.  相似文献   
957.
Image-guided laser ablation of osteoid osteoma in pediatric patients   总被引:1,自引:0,他引:1  
BACKGROUND: We aimed to evaluate the effectiveness of image-guided laser ablation for the treatment of osteoid osteomas in pediatric patients. METHODS: From June 1994 to June 2006, 68 patients aged 3 to 18 years (mean age, 12.1 +/- 4.2 years) with a diagnosis of osteoid osteoma underwent laser ablation in our department. Among them, 3 patients had prior unsuccessful attempt of surgical resection. Procedures were performed under spinal or general anesthesia with combined computed tomographic and fluoroscopic guidance. An 18-gauge needle was placed in the nidus after bone drilling when required, and an optical fiber was inserted through it. An average energy of 1200 J was delivered using an infrared diode laser generator. Patients were discharged the next day and followed up with assessment of pain, medication intakes, and potential complications. Clinical success was defined by complete pain relief without need for medication intake. RESULTS: Technical success was achieved in all but 1 of our first patients, which was subsequently treated by percutaneous resection. Overall clinical success was 98%. Primary clinical success was obtained in 60 patients (88%). In 7 patients, recurrence of symptoms at 4 to 27 months from the initial procedure was managed by repeat laser ablation, resulting in secondary success (10%). No complications related to the procedure were observed. Follow-up ranged 16 to 146 months (mean, 83 months). CONCLUSIONS: Currently, image-guided laser ablation is a safe and effective procedure that can be proposed as the mainstay treatment of osteoid osteomas in pediatrics. LEVEL OF EVIDENCE: Therapeutic case series study level IV.  相似文献   
958.
OBJECTIVE: To evaluate amiodarone prophylaxis in diabetics and non-diabetics. Further to clarify whether the risk of developing atrial fibrillation is higher for diabetics than non-diabetic patients, and to evaluate whether the diabetic status has any influence on the length of in-hospital stay. DESIGN: Subgroup analysis within a randomized, controlled, double-blinded trial. RESULTS: At 30 days of follow-up atrial fibrillation was equally frequent among diabetics (22%) and non-diabetics (17%) (p =0.41). The length of in-hospital stay for diabetics was prolonged with 25% (9%; 45%). The prophylactic amiodarone was found equally efficient in diabetics and non-diabetics, as the relative risk ratios were 1.2 (0.4-5.4) and 2.0 (0.3-12.5), respectively. CONCLUSIONS: Diabetics and non-diabetics had the same effect of the amiodarone prophylaxis regime. Atrial fibrillation developed equally among diabetics and non-diabetics, but the length of stay was prolonged for diabetics.  相似文献   
959.
Objective: Cardiac surgery employing cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) can induce coagulation disturbances and bleeding complications that may be especially severe in infants. A better understanding of the coagulopathy and a quick method for its evaluation would be helpful in the management of patients exposed to CPB and DHCA. This study aimed to monitor coagulation defects in congenital heart surgery using rotational thromboelastometry (ROTEM((R))), standard coagulation tests and platelet flow cytometry. Methods: The study comprised 10 infants undergoing surgery for congenital heart disease on CPB and DHCA. Blood was sampled at skin incision, after heparinisation during CPB (directly pre- and directly post-DHCA) and after protamine administration post-CPB. ROTEM((R)) using different reagents including a heparinase-containing assay to evaluate coagulation during heparinisation, APTT and INR, and flow cytometry to evaluate platelet activation were performed. Results: During CPB, the ROTEM((R)) indicated CPB-induced clotting factor depletion and platelet dysfunction that persisted after CPB and heparin neutralisation. ROTEM((R)) results were available within 15min and therefore much faster than standard tests. ROTEM((R))-guided specific blood product treatment resulted in satisfactory coagulatory function. The highest degree of platelet activation was found directly after DHCA. Conclusions: A major benefit of ROTEM((R)) is the quick detection of a developing coagulopathy already during CPB. ROTEM((R)) guides quick and specific blood product treatment after CPB, which may decrease bleeding complications in cardiac surgery. The finding of maximal platelet activation directly after DHCA suggests that not only CPB but also hypothermia activates platelets in vivo, thereby contributing to platelet dysfunction.  相似文献   
960.
OBJECTIVE: Because chylothorax complicating thoracic surgery is difficult to diagnose and failure of nonoperative management necessitates further surgery, we critically evaluated an evolving percutaneous strategy for diagnosing and treating chylothorax. METHODS: After thoracic surgery, 37 patients with a clinical diagnosis of chylothorax were referred for lymphangiography for definitive diagnosis and percutaneous treatment. Successful localization of the cisterna chyli by lymphangiogram facilitated percutaneous cannulation of the thoracic duct and its embolization. In patients in whom cannulation was not possible, the thoracic duct was percutaneously disrupted. RESULTS: Diagnosis: Lymphangiography was successful in 36 of the 37 patients (97%). Contrast extravasation, confirming clinical diagnosis, was present in 21 of the 36 (58%). Management: Twenty-one of 36 patients underwent 22 lymphangiographically directed percutaneous interventions: 12 embolizations and 10 disruptions. Mortality was zero, with two manageable complications. Patients without percutaneous intervention were discharged a median of 7 days (range 4-58) after first lymphangiography, 8 days (range 2-19) after percutaneous embolization, and 19 days (range 6-48) after first disruption. Eight patients had nine subsequent reoperations for chylothorax, two with negative lymphangiograms; no embolization patient required reoperation. CONCLUSIONS: There is a discrepancy between the clinical diagnosis of chylothorax after thoracic surgery and the presumed gold standard of diagnosis, contrast extravasation at lymphangiogram. Percutaneous treatment by thoracic duct embolization or disruption is safe and may obviate reoperation, but embolization of the thoracic duct is preferable to its disruption.  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