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   2248篇
  免费   285篇
  国内免费   10篇
耳鼻咽喉   12篇
儿科学   95篇
妇产科学   27篇
基础医学   239篇
口腔科学   37篇
临床医学   286篇
内科学   672篇
皮肤病学   49篇
神经病学   84篇
特种医学   270篇
外科学   172篇
综合类   83篇
预防医学   163篇
眼科学   33篇
药学   177篇
中国医学   9篇
肿瘤学   135篇
  2021年   17篇
  2020年   19篇
  2019年   24篇
  2018年   34篇
  2017年   28篇
  2016年   30篇
  2015年   37篇
  2014年   67篇
  2013年   91篇
  2012年   77篇
  2011年   66篇
  2010年   61篇
  2009年   84篇
  2008年   71篇
  2007年   87篇
  2006年   84篇
  2005年   73篇
  2004年   57篇
  2003年   48篇
  2002年   56篇
  2001年   57篇
  2000年   49篇
  1999年   47篇
  1998年   95篇
  1997年   68篇
  1996年   79篇
  1995年   54篇
  1994年   58篇
  1993年   63篇
  1992年   42篇
  1991年   31篇
  1990年   42篇
  1989年   68篇
  1988年   62篇
  1987年   53篇
  1986年   51篇
  1985年   42篇
  1984年   34篇
  1983年   40篇
  1982年   32篇
  1981年   36篇
  1980年   32篇
  1979年   41篇
  1978年   25篇
  1977年   41篇
  1976年   22篇
  1975年   25篇
  1974年   22篇
  1972年   16篇
  1971年   17篇
排序方式: 共有2543条查询结果,搜索用时 78 毫秒
1.
The surgical risk of colectomy in patients with cirrhosis   总被引:5,自引:1,他引:4  
The records of 54 patients with documented cirrhosis who underwent colectomy between January 1970 and January 1984 were studied to assess the operative risk and to determine the preoperative predictive risk factors. In-hospital mortality was 24 percent (13 patients), and postoperative complications occurred in 48 percent (26 patients). The risk of surgical intervention was significantly increased if encephalopathy, ascites, anemia, or hypoalbuminemia was present before operation. A simple operative risk index involving the presence of encephalopathy and ascites and the levels of hemoglobin and albumin is proposed to help distinguish a low-risk subgroup in whom postoperative mortality was 12.8 percent from a high-risk subgroup in whom postoperative mortality was 53.3 percent.  相似文献   
2.
The results of a community-based survey on knowledge and beliefs about tuberculosis in non-working women are presented. The women in the sample showed a very good knowledge of the important aspects of tuberculosis: 90% were aware that it is a problem in their area; 97% knew that it affects the chest; 94% said that it could be fatal; 85% considered it to be infectious and 88% knew that the local clinic provided treatment. Their knowledge of symptoms was good overall but the study revealed misconceptions about the causes and transmission of tuberculosis; 16% indicated that they would not be keen to associate with people with tuberculosis owing to fear of infection. The design effect of cluster sampling was considered in the analysis. The highest design effects (i.e. the most clustering of responses) were found for responses to questions on the causes of tuberculosis and places where treatment could be obtained, possibly reflecting that these beliefs are influenced by neighbourhood contacts. Future tuberculosis education in this group needs to build on existing knowledge and awareness and should focus on changing attitudes such as misconceptions about transmission and the stigmatisation of the disease. Health workers face the challenge of changing behaviour in this community to ensure that people with symptoms present early for screening and that people diagnosed as having tuberculosis comply with treatment.  相似文献   
3.
目的 探讨创伤后迟发性脑肿胀的临床特点、发病机制与治疗。方法 回顾性分析1998年1月~2005年6月年收治的17例迟发性脑肿胀患者的临床特点和救治情况。结果 所有颅脑损伤患者采用保守治疗后均有好转,但于伤后5-10d出现恶化,CT复查有脑肿胀,经加强综合脱水等治疗后16例治愈,1例死亡。结论 迟发性脑肿胀好发于对冲性额、颞叶挫裂伤伴明显蛛网膜下腔出血、硬膜下薄层血肿及早期CT有脑肿胀者。其发病机制可能与创伤后的迟发性脑血管痉挛、微循环障碍、静脉回流障碍及甘露醇作用下降等因素有关。此类患者病情隐蔽性强,应加强观察、积极行CT复查,如能早期明确诊断,保守治疗多数效果良好。  相似文献   
4.
5.
How many cancers are reversible or suppressible?   总被引:1,自引:0,他引:1  
D Metcalf 《Pathology》1983,15(1):1-3
  相似文献   
6.
Retrorenal colon: implications for percutaneous diskectomy   总被引:1,自引:0,他引:1  
Helms  CA; Munk  PL; Witt  WS; Davis  GW; Morris  J; Onik  G 《Radiology》1989,171(3):864-865
It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary.  相似文献   
7.
8.
9.
10.
J. Lindsay  J.S. Metcalf  G.A. Codd   《Toxicon》2006,48(8):995-1001
Purified cyanobacterial lipopolysaccharide (LPS) was not acutely toxic to three aquatic invertebrates (Artemia salina, Daphnia magna and Daphnia galeata) in immersion trials. However, pre-exposure (24 h) to 2 ng mL−1 LPS increased the LC50 of microcystin-LR significantly in all 3 species. Similar results were observed with A. salina pre-treated with the same concentration of cyanobacterial LPS and subsequently exposed to cylindrospermopsin, increasing the LC50 by 8. The findings indicate the need to include exposures to defined combinations of cyanotoxins, and in defined sequences, to understand the contributions of individual cyanotoxins in accounting for cyanobacterial toxicity to invertebrates in natural aquatic environments.  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