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   11670篇
  免费   780篇
  国内免费   61篇
耳鼻咽喉   129篇
儿科学   380篇
妇产科学   274篇
基础医学   1647篇
口腔科学   241篇
临床医学   1096篇
内科学   2733篇
皮肤病学   264篇
神经病学   969篇
特种医学   386篇
外科学   1445篇
综合类   188篇
一般理论   12篇
预防医学   797篇
眼科学   278篇
药学   921篇
  1篇
中国医学   28篇
肿瘤学   722篇
  2023年   77篇
  2022年   127篇
  2021年   251篇
  2020年   124篇
  2019年   158篇
  2018年   243篇
  2017年   200篇
  2016年   232篇
  2015年   282篇
  2014年   368篇
  2013年   511篇
  2012年   623篇
  2011年   625篇
  2010年   366篇
  2009年   421篇
  2008年   581篇
  2007年   642篇
  2006年   594篇
  2005年   574篇
  2004年   580篇
  2003年   498篇
  2002年   518篇
  2001年   233篇
  2000年   194篇
  1999年   187篇
  1998年   196篇
  1997年   165篇
  1996年   170篇
  1995年   126篇
  1994年   145篇
  1993年   115篇
  1992年   155篇
  1991年   166篇
  1990年   125篇
  1989年   163篇
  1988年   151篇
  1987年   138篇
  1986年   139篇
  1985年   101篇
  1984年   98篇
  1983年   81篇
  1982年   94篇
  1981年   71篇
  1980年   69篇
  1979年   55篇
  1978年   54篇
  1977年   54篇
  1976年   56篇
  1975年   72篇
  1971年   45篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.

Background

Portomesenteric venous thrombosis (PMVT) is uncommon but associated with ischemic bowel and mortality.

Objective

The purpose of this study was to determine the occurrence of PMVT in a community setting and evaluate current diagnosis, treatment, and outcomes.

Methods

Medical records of consecutive patients admitted to a community-based hospital diagnosed with PMVT were reviewed. Patients were divided into 2 groups: those diagnosed from 1997 to 2003 and those diagnosed from 2004 to 2009.

Results

One hundred three patients were included. The proportion of chronic PMVT diagnoses increased in the recent group (14% in contrast to 44%, P = .001). Treatment was more common in acute in contrast to chronic PMVTs (70% in contrast to 48%, P = .035). The median length of stay decreased over time (6 in contrast to 3 days, P = .004). Three patients underwent surgical intervention. Overall, 30-day mortality was 17% and did not change over time.

Conclusions

Diagnosis and treatment have changed with increased differentiation between acute and chronic PMVT; outcomes were similar. Surgical intervention was rarely necessary. Mortality is attributed to patient comorbidity rather than PMVT.  相似文献   
122.
The primary objective of this study was to evaluate morbidity associated with facial translocation approaches for skull base and results of various technical modifications. Forty consecutive patients who underwent facial translocation approaches for accessing skull base tumors from July 2005 to June 2010 were included in this study. There were 25 patients who underwent standard facial translocation, 4 patients medial mini, and 11 patients underwent extended facial translocation. Thirteen patients had benign disease and 27 patients had malignant disease. Resection was R0 in 36 and R1 in 4 patients. Most patients had acceptable cosmetic results. None of the patients had problems related to occlusion or speech and swallowing. The commonest complication observed was nasal crusting in 16 patients. Grade 2 trismus and exposure of mini plate was seen in three patients. Two patients developed necrosis of translocated bone. Three patients developed palatal fistula before modification of palatal incision. Facial translocation provides a satisfactory access for adequate clearance of skull base tumors with satisfactory aesthetic and functional results. With modifications of the surgical technique and implementation of new surgical tools, the morbidity of facial translocation approaches will continue to decrease.  相似文献   
123.
PURPOSE: Laparoscopic partial/wedge nephrectomy, similar to laparoscopic radical prostatectomy, is a technically challenging procedure that is performed by a limited number of expert laparoscopic surgeons. The incorporation of a robotic surgical interface has dramatically increased the use of minimally invasive pelvic surgery such that robotic laparoscopic radical prostatectomy is commonly performed even by laparoscopically na?ve surgeons. This analysis compares the outcomes of our initial experience with robot-assisted laparoscopic partial nephrectomy (RLPN) performed by an experienced open surgeon to that of standard laparoscopic partial nephrectomy (LPN) performed by two experienced laparoscopic surgeons. PATIENTS AND METHODS: We reviewed the medical records of 11 consecutive patients who underwent 12 standard LPNs (EMM, RVC) (one patient had two unilateral tumors) and 10 consecutive patients (representing the first 11 of such robotic procedures performed at our institution) who underwent 11 RLPNs (one patient had bilateral tumors managed in an asynchronous manner) (DKO). RESULTS: The mean tumor size was 2.3 cm (range 1.7-6.2 cm) for LPN and 3.1 cm (range 2.5-4 cm) for RLPN. The mean total procedure time was 289.5 minutes (range 145-369 min) for LPN and 228.7 minutes (range 98-375 min) for RLPN (P=0.102). The mean estimated blood loss was 198 mL (range 75-500 mL) for LPN v 115 mL (25-300 mL) for RLPN (P=0.169). The mean warm ischemia time was 35.3 minutes (range 15-49 min) in the LPN group and 32.1 minutes (range 30-45 minutes) in the RLPN group (P=0.501). CONCLUSIONS: Introducing a robotic interface for laparoscopic partial/wedge resection allowed a fellowship-trained urologic oncologist with limited reconstructive laparoscopic experience to achieve results comparable to those for laparoscopic partial/wedge resection performed by experienced laparoscopic surgeons. In this regard, the learning curve appears truncated, similar to that with robot-assisted laparoscopic prostatectomy.  相似文献   
124.
OBJECTIVE: Despite the many procedures introduced to prevent surgical site infection during cardiothoracic surgery, serious infections still occur. We attempted to reduce surgical site infection by spraying antibiotic solution in the operative field--a procedure since introduced at 4 other Japanese institutions. METHODS: In the latter half of 1990, we began spraying an antibiotic solution of cefazolin (1g) and gentamicin (40 mg)/40 ml of saline placed in a 50 ml syringe and dispensed through an 18 G needle bent at 60 to 80 degrees to clean the wound during surgery. RESULT: No deep surgical site infections or deaths due to infection have occurred among the 502 patients undergoing cardiothoracic surgery under cardiopulmonary bypass at our hospital. This method was used in over 2,100 cases of similar procedures at 4 other institutions. There were 3 deaths due to severe surgical site infection (0.11%). At one institution treating over 1,000 cases a year, the incidence of death due to surgical site infection decreased significantly after this method was introduced. CONCLUSION: These preliminary experiences show that spraying antibiotic solution in the operative field reduces the risk of surgical site infection in cardiothoracic surgery.  相似文献   
125.
Heme oxygenase isoform-specific expression and distribution in the rat kidney   总被引:10,自引:0,他引:10  
BACKGROUND: The heme oxygenase (HO) genes, HO-1 and HO-2, are the limiting steps in heme degradation and in the regulation of renal heme-dependent enzymes. Previously we reported that selective overexpression of renal HO-1 resulted in a decrease of microsomal heme and the cytochrome P450-dependent arachidonic acid metabolite, 20 HETE, a vasoconstrictor. The present study was undertaken to explore the relative expression and contribution of each of the HO isoforms to HO activity in the rat kidney. METHODS AND RESULTS. Renal HO activity increased above control levels after an injection of the inducers of HO activity, heme or SnCl2. Stannous Mesoporphyrin (SnMP), a nonselective inhibitor of HO, when used alone or in combination with heme or SnCl2, decreased HO activity. Heme alone and combined with SnCl2 decreased the levels of heme content by 13 and 35%, respectively. Western blot analysis showed that both SnCl2 and heme readily induced HO-1 protein, whereas HO-2 was constitutively expressed. Immunohistochemistry showed the distribution of the HO-1 isoform primarily in proximal convoluted tubules. Western blot analysis exhibited relatively higher levels of HO-1 in isolated proximal tubules and relatively higher HO-2 levels in the thick ascending limbs of the loop of Henle and preglomerular arterioles. In vivo administration of HO-1 and HO-2 antisense oligodeoxynucleotides further confirmed that HO-2, but not HO-1, contributed to the basal HO activity; however, following induction of HO with heme, antisense to HO-1, but not to HO-2, inhibited the induced levels of HO activity. CONCLUSION: These results suggest that HO-2 is constitutively expressed in the rat kidney mainly within tubular and arteriolar structures, and its activity may modulate physiological function under basal conditions. On the other hand, the basal levels of expression of HO-1 in the rat kidney are relatively low, and its contribution to HO activity and the regulation of hemoproteins such as cytochrome P450 become apparent only under pathophysiological conditions causing HO induction.  相似文献   
126.
Reoperative left anterior descending artery (LAD) revascularization can be performed through a left anterior small thoracotomy (LAST approach) in patients requiring isolated LAD revascularization. If the left internal mammary artery has been previously used, however, the operation is generally performed either through a median sternotomy or through a full posterolateral thoracotomy for the necessity of connecting the vein graft to the ascending aorta or to the descending thoracic aorta, thus losing the advantages of a minimally invasive approach. In the case reported herein, we describe a technique in which reoperative revascularization of the LAD is accomplished through the LAST approach, using the stump of the left internal mammary artery as the inflow site of a saphenous vein coronary graft to the LAD.  相似文献   
127.
PURPOSE: To compare our experience with laparoscopic radical cystectomy (LACIC) and robot-assisted laparoscopic radical cystectomy (RACIC) with ileal conduit urinary diversion. PATIENTS AND METHODS: Prospective data were gathered on 20 consecutive patients undergoing LACIC performed between August 2002 and July 2005, and on 14 consecutive patients undergoing RACIC performed between March 2005 and December 2006. Radical cystectomy with pelvic lymphadenectomy was performed laparoscopically or robotically, and an ileal conduit urinary diversion was performed extracorporeally. RESULTS: There was no significant difference in terms of preoperative factors or baseline tumor characteristics and no significant difference in mean operative time (410 min v 419 min) between groups. There was less blood loss (212 mL v 653 mL; P < 0.0001) and fewer transfusions (42.8% v 70%; P < 0.0011) in the RACIC group. There was one intraoperative complication (7%) and no conversions in the RACIC group. There were three (15%) intraoperative complications all leading to conversion in patients undergoing LACIC. Three (21%) patients in the RACIC group and 10 (50%) patients in the LACIC group had at least 1 post-operative complication. The mean number of days to oral intake was less in the RACIC group (2.3 v 6.1; P = 0.012). There was no significant difference in the number of lymph nodes excised (P = 0.09) between groups. Bilateral extended lymphadenectomy was performed in 10 (71%) RACIC patients with a mean of 22.3 lymph nodes harvested and in 16 (80%) LACIC patients with a mean of 16.5 lymph nodes harvested. There were no positive margins in patients in the LACIC group and one (7.1%) among patients in the RACIC group--a patient with pT4 disease. CONCLUSION: Both laparoscopic and robot-assisted radical cystectomies can be performed safely without compromising oncologic standards for surgical margins and extent of lymphadenectomy. In this early experience, the robot-assisted approach appears to have a shorter learning curve, and it is associated with less blood loss, fewer postoperative complications, and earlier return of bowel function than LACIC.  相似文献   
128.

Introduction

In response to the need for simple, rapid means of quantifying surgical capacity in low resource settings, Surgeons OverSeas (SOS) developed the personnel, infrastructure, procedures, equipment and supplies (PIPES) tool. The present investigation assessed the inter-rater reliability of the PIPES tool.

Methods

As part of a government assessment of surgical services in Santa Cruz, Bolivia, the PIPES tool was translated into Spanish and applied in interviews with physicians at 31 public hospitals. An additional interview was conducted with nurses at a convenience sample of 25 of these hospitals. Physician and nurse responses were then compared to generate an estimate of reliability. For dichotomous survey items, inter-rater reliability between physicians and nurses was assessed using the Cohen’s kappa statistic and percent agreement. The Pearson correlation coefficient was used to assess agreement for continuous items.

Results

Cohen’s kappa was 0.46 for infrastructure, 0.43 for procedures, 0.26 for equipment, and 0 for supplies sections. The median correlation coefficient was 0.91 for continuous items. Correlation was 0.79 for the PIPES index, and ranged from 0.32 to 0.98 for continuous response items.

Conclusions

Reliability of the PIPES tool was moderate for the infrastructure and procedures sections, fair for the equipment section, and poor for supplies section when comparing surgeons’ responses to nurses’ responses—an extremely rigorous test of reliability. These results indicate that the PIPES tool is an effective measure of surgical capacity but that the equipment and supplies sections may need to be revised.  相似文献   
129.
130.
The purpose of this study was to assess and compare the outcome of surgical decompression for spinal stenosis in diabetic and non-diabetic elderly patients. This is a retrospective chart analysis conducted in a university affiliated referral hospital. The participants were consecutive patients, age 65 and older, undergoing laminectomy for spinal stenosis during 1990–2000. We assessed patients clinical and demographic data, procedures, perioperative complications, preoperative and postoperative pain intensity, basic activities of daily living (BADL), patients satisfaction, the need for repeated surgery, and overall mortality. A total number of 62 elderly diabetic group (DG) patients undergoing decompression surgery for spinal stenosis were compared with a sex and age-matched non-diabetic control group (CG) at baseline, and a mean of 40.3 months thereafter. We found that the DG patients had more pain (p=0.042), and suffered more frequently from neurogenic claudication (p=0.0018), motor weakness (p=0.021) and numbness of the affected limb (p=0.0069) than the CG patients. Nocturnal pain was reported in 24% of the DG patients. Pain relief was successfully achieved in both groups (p<0.001), but the patients satisfaction was greater in the non-diabetic patients (p=0.0067). Revision surgery was more frequently performed in the DG than the CG (non-significant difference), and the time interval for such a second intervention was shorter (p=0.04) in the DG. A higher rate of post-operative complications was observed in the DG (p<0.0001). It is concluded that surgical treatment of elderly diabetic patients suffering from spinal stenosis improves BADL and ameliorates pain, but the results remain worse than those observed in non-diabetics. The outcome of diabetic patients depends upon the presence of other comorbidities, concurrent diabetic neuropathy, duration of diabetes and insulin treatment. Successful postoperative pain reduction remained the strongest factor associated with patients satisfaction.  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