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   40307篇
  免费   2512篇
  国内免费   266篇
耳鼻咽喉   476篇
儿科学   1197篇
妇产科学   1205篇
基础医学   4288篇
口腔科学   1149篇
临床医学   3309篇
内科学   8434篇
皮肤病学   844篇
神经病学   1918篇
特种医学   1396篇
外国民族医学   18篇
外科学   7103篇
综合类   997篇
现状与发展   2篇
一般理论   31篇
预防医学   3116篇
眼科学   1180篇
药学   3642篇
中国医学   281篇
肿瘤学   2499篇
  2023年   452篇
  2022年   1481篇
  2021年   2275篇
  2020年   1203篇
  2019年   1542篇
  2018年   2041篇
  2017年   1258篇
  2016年   1275篇
  2015年   1403篇
  2014年   1835篇
  2013年   2211篇
  2012年   3163篇
  2011年   3310篇
  2010年   1794篇
  2009年   1395篇
  2008年   2009篇
  2007年   2115篇
  2006年   1896篇
  2005年   1724篇
  2004年   1553篇
  2003年   1379篇
  2002年   1264篇
  2001年   461篇
  2000年   424篇
  1999年   381篇
  1998年   227篇
  1997年   186篇
  1996年   169篇
  1995年   164篇
  1994年   126篇
  1993年   103篇
  1992年   177篇
  1991年   174篇
  1990年   168篇
  1989年   146篇
  1988年   142篇
  1987年   136篇
  1986年   135篇
  1985年   121篇
  1984年   107篇
  1983年   119篇
  1982年   68篇
  1981年   67篇
  1980年   51篇
  1979年   87篇
  1978年   59篇
  1977年   64篇
  1976年   58篇
  1975年   52篇
  1974年   50篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
BACKGROUND: Thiazolidinediones (TZD) have been reported to improve early stages of diabetic nephropathy independent of glycaemic control. Since blockade of the renin-angiotensin system (RAS) is known to reduce the risk of nephropathy, we hypothesised that the renal effect of TZDs might be related to a favourable effect on the intrarenal RAS. We aimed to determine if the TZD rosiglitazone could reduce RAS activation. METHODS: We studied adult type 2 diabetic patients and placed them on rosiglitazone for three months. We have previously used the renal haemodynamic response to angiotensin-converting enzyme (ACE) inhibition to demonstrate the state of RAS activation, and thus measured renal plasma flow (RPF) and glomerular filtration rate (GFR) before and after administration of captopril at 0 month and at three months. Plasma renin activity (PRA), active renin, aldosterone and natriuretic peptides were analysed. RESULTS: The RPF response to ACE inhibition was not altered. There was no change in GFR, PRA, active renin and aldosterone levels. Two patients developed oedema one had an elevated baseline active renin and another had an elevated baseline aldosterone level. CONCLUSION: The favourable effects of TZDs on diabetic nephropathy is likely not related to an influence on the RAS.  相似文献   
112.
113.
114.
115.
116.
117.
118.
BACKGROUND AND OBJECTIVES: Inguinal hernia repair is one of the most frequently performed pediatric surgical operations. Several pediatric laparoscopic inguinal hernia repair techniques have been introduced. But debate is unresolved regarding the feasibility of laparoscopy for treating pediatric inguinal hernias. METHODS: A retrospective cohort study enrolled 33 patients who underwent congenital inguinal hernia repair by either the new laparoscopic flip-flap technique or conventional open repair. Patients were divided into 2 groups according to the type of surgery: Group A included those who underwent the new laparoscopic technique, and Group B included those who underwent conventional open repair. RESULTS: Group A comprised 15 patients (mean age, 39 months), and group B comprised 18 (mean age, 44 months). Mean operative time was 47.5 minutes for Group A versus 27.5 minutes for Group B. Intraoperative complications for Group A included 1 case (7%) of vas deferens injury, and 3 cases (20%) in which the flaps were torn during suturing. In Group B, no intraoperative complications were encountered. In both groups, the mean postoperative hospital stay was 5.5 hours. Postoperative follow-up of 3 months revealed recurrence in 4 patients in Group A (27%), while there were no recurrences in Group B. CONCLUSION: Our preliminary experience shows unsatisfactory outcomes with laparoscopic flip-flap hernia repair in children. In spite of advancement in the application of laparoscopy in pediatric surgery, conventional open hernia repair is still the gold standard for children, in our experience. Future studies with more numbers and longterm follow-up should be conducted.  相似文献   
119.
Background: Surgical intervention in patients with malignant hematological disorders is a major undertaking due to the expected risks of bleeding, infection and poor wound healing. Methods and materials: A retrospective study of patients treated at the Riyadh Armed Forces Hospital, Saudi Arabia between January 1991 and December 2002 was conducted. The results of patients with acute leukemia and lymphoma who underwent surgical procedures (study group) were compared with those of a control group composed of patients with the same spectrum of disorders treated over the same period of time and given the same treatment protocols but never required any surgery. Results: No single death occurred intraoperatively or in the immediate postoperative period due to surgical therapy per se. However, follow up of both groups of patients revealed a shorter long‐term survival and higher rates of relapse and severe invasive infections in the surgical group compared to the control group of patients. The mean survival for the study group was 1871 ± 307 days versus 3094 ± 279 days for the control group of patients (P = 0.0027). Thirty (75%) study patients suffered relapses of their malignant hematological disorders versus 23 (37.1%) control patients. Forty‐five relapses were encountered in the study group of patients (1.5 relapses per relapsed patient) versus 26 relapses in the control group (1.13 relapses per relapsed patient). Various infections occurred in 37 (92.5%) study patients and 32 (51.6%) control patients. Recurrent infections developed in 30 (75%) study patients and 22 (35.5%) control patients (P = 0.00008). Infections causing tissue invasion were encountered in 29 (72.5%) study patients and 22 (35.5%) control patients. Conclusion: Even major surgical procedures can be performed in patients with leukemia or lymphoma provided enough preparatory measures are made to minimize bleeding and infectious complications. Surgery may, however, be associated with long‐term complications such as a high incidence of relapse of the primary malignant hematological disorder and an increased rate of severe and invasive infections.  相似文献   
120.
A 48‐year‐old male patient with long‐standing ulcerative colitis since February 2001 which was diagnosed by endoscopy, developed acute digital ischemia affecting both hands with fixed colour changes in the left index finger which was followed shortly by digital ulceration. Magnetic resonance angiography (MRA) of both upper limbs showed evidence of vasculitis affecting digital arterioles on both sided and right subclavian occlusion. The patient received pulse methylprednisolone followed by cyclophosphamide pulse therapy, the latter continuing on a monthly basis for 6 months with appreciable improvement and remission of the vasculitic process; follow‐up MRA showed reperfusion of the previously occluded subcalvian artery. To the authors’ knowledge vasculitis complicating the course of ulcerative colitis is a rare association and is only sporadically reported in the literature. This rare entity should be diagnosed early and aggressively treated; MRA is a very promising diagnostic tool that is suitable for both diagnosis and follow‐up of patients with this rare entity.  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