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   379122篇
  免费   24174篇
  国内免费   2808篇
耳鼻咽喉   5184篇
儿科学   8201篇
妇产科学   10077篇
基础医学   53119篇
口腔科学   11803篇
临床医学   30106篇
内科学   78291篇
皮肤病学   8551篇
神经病学   27198篇
特种医学   13913篇
外国民族医学   82篇
外科学   60578篇
综合类   9957篇
现状与发展   1篇
一般理论   64篇
预防医学   17431篇
眼科学   9451篇
药学   30987篇
  1篇
中国医学   2194篇
肿瘤学   28915篇
  2021年   2617篇
  2019年   2725篇
  2018年   4517篇
  2017年   3430篇
  2016年   3520篇
  2015年   4016篇
  2014年   5694篇
  2013年   7377篇
  2012年   10028篇
  2011年   10202篇
  2010年   6193篇
  2009年   5838篇
  2008年   9447篇
  2007年   10292篇
  2006年   10199篇
  2005年   9271篇
  2004年   8777篇
  2003年   8511篇
  2002年   8186篇
  2001年   28240篇
  2000年   28774篇
  1999年   23653篇
  1998年   5165篇
  1997年   4255篇
  1996年   3829篇
  1995年   3487篇
  1994年   3104篇
  1993年   2845篇
  1992年   16048篇
  1991年   14814篇
  1990年   14160篇
  1989年   13965篇
  1988年   12583篇
  1987年   12066篇
  1986年   11110篇
  1985年   10322篇
  1984年   6913篇
  1983年   5601篇
  1982年   2720篇
  1979年   5481篇
  1978年   3348篇
  1977年   2972篇
  1975年   2642篇
  1974年   3065篇
  1973年   2866篇
  1972年   2828篇
  1971年   2773篇
  1970年   2512篇
  1969年   2545篇
  1968年   2250篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
172.
173.
OBJECTIVES: Local anaesthetic infiltration into the carotid sinus during carotid endarterectomy (CEA) has been recommended to minimise blood pressure fluctuations but its use remains controversial. The aim of this meta-analysis was to determine whether intra-operative administration of local anaesthetic reduces the incidence of haemodynamic instability following CEA. MATERIALS AND METHODS: A search of the Medline, Pubmed and Embase databases and the Current Controlled Trials register identified four trials, which met the pre-defined inclusion criteria for data extraction. Pooled odds ratios with 95 per cent confidence intervals (c.i.) for the development of post-operative hypotension and hypertension were calculated using a random-effects model. RESULTS: Outcomes of 432 patients were studied. Local anaesthetic blockade of the carotid sinus was associated with a pooled odds ratio of 1.25 (95 per cent c.i. 0.496 to 3.15); p=0.216) and 1.28 (95 per cent c.i. 0.699 to 2.33; p=0.428) for the development of post-operative hypotension and hypertension respectively. Although none reach significance there was a trend towards increased risk of developing a complication in those patients who received local anaesthetic. CONCLUSIONS: There are insufficient data to determine the role of intra-operative local anaesthetic administration in reducing post-operative blood pressure lability following CEA. Conversely, the possibility of harm cannot be excluded on the basis of the currently available data.  相似文献   
174.
175.
S M Y Ahmed  J Singh  M Nicol 《The surgeon》2007,5(6):363-367
There are various methods of reducing anterior shoulder dislocations. The traditionally used methods like Kocher's and Hippocratic are associated with procedural complications and frequently require sedation/muscle relaxants which have their own complications and are associated with longer stay and monitoring requirement in the emergency department. We describe a stepped care approach to shoulder dislocation reduction in the prone position involving four steps and two new manipulation methods taking into consideration the pathological deforming forces in a dislocated shoulder and addressing them in a stepwise fashion. This method does not require sedation/muscle relaxants in the majority of cases, is easy to learn, relatively painless, associated with shorter stay in the emergency department and has fewer complications.  相似文献   
176.
BACKGROUND: Microalbuminuria and macroalbuminuria constitute risk factors for ESRD and death in non-transplanted populations. Whether microalbuminuria (especially in non-proteinuric patients) and macroalbuminuria constitute risk factors for graft loss and death is presently unknown in renal transplantation. METHODS: We retrospectively assessed the association between urinary albumin excretion (UAE) and ESRD and death in renal transplantation. RESULTS: UAE was measured in 616 (397 proteinuric; 219 non-proteinuric patients) renal transplant recipients. They were grafted for 62 months (range: 6-192). During the 40 months (3.7-99) thereafter, 31 patients underwent dialysis and 32 died. Microalbuminuria (vs. normoalbuminuria) and macroalbuminuria (vs. microalbuminuria) were powerful risk factors for graft loss [OR: 14.25 (2.88-52.3) and 16.41 (7.46-36.0), respectively, both p < 0.0001], even after adjustments on renal function and diabetes. Among the 219 non-proteinuric patients, microalbuminuria (vs. normoalbuminuria) was a significant risk factor for graft loss [OR: 23.09 (1.93-276.4), p = 0.0132]. Both microalbuminuria (vs. normoalbuminuria) [OR: 5.55 (2.43-12.66), p < 0.0001] and macroalbuminuria (vs. microalbuminuria) [OR: 4.12 (1.65-10.29), p = 0.0024] were predictive of death. CONCLUSIONS: Microalbuminuria and macroalbuminuria are powerful independent predictors of ESRD and death. Microalbuminuria is a risk factor for graft loss even in non-proteinuric patients. UAE provides additional information on renal and patient prognosis as compared to proteinuria and renal function.  相似文献   
177.
Little is known about the effects of immunosuppression on patients with hereditary nonpolyposis colorectal cancer (HNPCC). We describe a kidney transplant recipient with unrecognized Muir-Torre syndrome in whom the administration of a tacrolimus-based regimen led to the eruption of multiple sebaceous tumors. The patient was later found to harbor an MSH2 mutation. Switching to a sirolimus-based regimen resulted in arrest of the disease. When the patient was switched back to tacrolimus, new facial lesions rapidly appeared. Switching again to sirolimus resulted again in halting the appearance of new lesions. This finding is in line with the known antiangiogenic activity of sirolimus and reports on the regression of cutaneous Kaposi's sarcoma in kidney transplant recipients switched from another immunosuppressive regimen to sirolimus. Further studies on the potential use of sirolimus for the treatment of de novo tumors in immunosuppressed kidney transplant recipients with HNPCC are warranted.  相似文献   
178.
The aqueous extract of the fruits of Terminalia chebula Retz. has been evaluated for its antidiabetic activity in streptozotocin (STZ) induced mild diabetic rats and compared with a known drug, tolbutamide. The oral effective dose (ED) of the extract was observed to be 200 mg/kg body weight, which produced a fall of 55.6% (p<0.01) in the oral glucose tolerance test. Oral administration of ED of aqueous extract of T.chebula (AETC) daily once for two months reduced the elevated blood glucose by 43.2% (p<0.01) and significantly reduced the increase in glycosylated hemoglobin (HbA1c) (p<0.01). The same dose also showed a marked improvement in controlling the elevated blood lipids as well as decreased serum insulin levels in contrast to the untreated diabetic animals. Hepatic and skeletal muscle glycogen content decreased by 75% and 62.9% respectively in diabetic controls, these alterations were partly prevented (34.9% and 21.17%) in AETC treated group when compared to the healthy controls. The in vitro studies with pancreatic islets showed that the insulin release was nearly two times more than that in untreated diabetic animals. The treatment did not have any unfavorable effect on other blood parameters of liver and kidney function tests. LD 50 was found to be above 3 g/kg bw i.e. 15 times of ED, because there were no deaths of animals even at this dose indicating high margin of safety. These findings suggest further investigations for the possible use of the aqueous extract of fruits of T.chebula for the treatment of diabetes.  相似文献   
179.
180.
Purpose Post operative monitoring is crucial for the success of microsurgical free tissue transfer. Sophisticated and expensive methods are available for monitoring. We propose a novel technique using digital photography and the internet as a reliable and cost effective method to monitor free tissue transfers. Methods 163 micro‐vascular procedures were monitored using this technique over 8 months. Serial photographs taken to show flap color. Capillary refill time, pin prick‐ bleed time and color and hand held Doppler signal was recorded in the movie mode of a standard 5 mega pixel camera with duration of 15 seconds. Data was sent to the surgeon at regular intervals and or as deemed necessary. Results Analysis of the 67 cases is presented. 5 re‐explorations were done. The early diagnosis of venous congestion was possible using this technique. Timely intervention contributed to the success of the re‐explorations and these flaps could be salvaged. The file size of images was in the range of 1 MB–6 MB. The file size of an entire set of images ranged about 7 MB–9 MB. These were sent across the ADSL internet lines. Conclusion The use of the digital images and the internet allow reconstructive surgeons to have a reliable picture of the state of their free tissue transfers. This permits decrease in observer error and saves valuable time which otherwise needs to be spent to verify situations of doubt and offers an ideal solution to the logistic problem of having to visit the patient in case of doubt.  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