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   8938篇
  免费   876篇
  国内免费   38篇
耳鼻咽喉   76篇
儿科学   223篇
妇产科学   170篇
基础医学   1361篇
口腔科学   185篇
临床医学   980篇
内科学   2036篇
皮肤病学   119篇
神经病学   741篇
特种医学   416篇
外科学   1194篇
综合类   196篇
一般理论   7篇
预防医学   861篇
眼科学   91篇
药学   657篇
  1篇
中国医学   4篇
肿瘤学   534篇
  2021年   128篇
  2019年   109篇
  2018年   119篇
  2016年   78篇
  2015年   114篇
  2014年   159篇
  2013年   216篇
  2012年   335篇
  2011年   398篇
  2010年   200篇
  2009年   191篇
  2008年   316篇
  2007年   307篇
  2006年   324篇
  2005年   350篇
  2004年   313篇
  2003年   310篇
  2002年   270篇
  2001年   308篇
  2000年   283篇
  1999年   264篇
  1998年   162篇
  1997年   109篇
  1996年   118篇
  1995年   103篇
  1994年   106篇
  1993年   110篇
  1992年   234篇
  1991年   220篇
  1990年   224篇
  1989年   201篇
  1988年   205篇
  1987年   212篇
  1986年   223篇
  1985年   200篇
  1984年   145篇
  1983年   164篇
  1982年   106篇
  1981年   111篇
  1980年   88篇
  1979年   145篇
  1978年   142篇
  1977年   111篇
  1976年   110篇
  1975年   105篇
  1974年   118篇
  1973年   107篇
  1970年   79篇
  1969年   74篇
  1968年   73篇
排序方式: 共有9852条查询结果,搜索用时 796 毫秒
11.
12.
A Decade of Change in Obesity Surgery   总被引:4,自引:0,他引:4  
Background: The International (formerly National) Bariatric Surgery Registry began collecting data in January 1986. The aim of this study was to examine changes in the practice of surgical treatment of severe obesity that occurred during the decade of 1986 through 1995, as observed in the IBSR data. Methods: All data submitted to the IBSR during the decade were transferred to the IBM mainframe computer for analysis. Characteristics of operative type populations were compared over time using analysis of variance (ANOVA) for age, body mass index (BMI), operative weight and Chi-square (χ2) test for gender. Results: There has been a steady increase over the decade in mean patient weight. The operations used have changed from predominantly ‘simple’ operations to more frequent use of ‘complex’ operations. Within the categories of ‘simple’ and ‘complex’, an increase in the variety of operations occurred. As a group, patients with ‘simple’ operations have been heavier, more often male and public pay patients than those who have undergone ‘complex’ operations. One year weight loss was greater for Roux-en-Y gastric bypass (RGB) than vertical banded gastroplasty (VBG), but follow-up rates were too low to study the relative merits of the operations used. The reported incidence of operative mortality and serious complications (leak with peritonitis, abscess and pulmonary embolism) remained low. Conclusions: These observations and their implications can be summarized in three statements which relate to action for improved patient care in the beginning of the new century: (1) increasing weight of candidates for surgical treatment during this decade indicates the need for earlier use of operative treatment before irreversible complications of obesity can develop; (2) low risk of obesity surgery, decreasing postoperative hospital stay, and early weight control support the continued and increased use of surgical treatment; (3) continued widespread use of both ‘simple’ and ‘complex’ operations with increased modifications of standard RGB and VBG procedures emphasizes the need for standardized long-term data and analyses regarding both weight control and postoperative side-effects.  相似文献   
13.
Drawing upon preliminary research findings, this paper considers whether pharmacists in Britain face a crisis in their occupational status and identity as a result of changes in their work and market situations. It further examines some of the ways in which they are responding to the challenges and opportunities presented. The paper also comments on the utility of the concepts of 'reprofessionalization' and 'occupational imperialism' in the study of British pharmacy.  相似文献   
14.
15.
Biodegradable controlled-release microsphere systems made with the biocompatible biodegradable polyester excipient poly [DL lactide-co-glycolide] constitute an exciting new technology for drug delivery to the central nervous system (CNS). The present study describes functional observations indicating that implantation of dopamine (DA) microspheres encapsulated within two different polymer excipients into denervated-striatal tissue assures a prolonged release of the transmitter in vivo. Moreover, in this regard, the results show that there were clear cut temporal differences in the effect of the two DA microsphere formulations compared in this study, probably reflecting variations in the actual composition (i.e., lactide to glycolide ratio) of the two copolymer excipients examined. This technology has considerable potential for basic research with possible clinical application.  相似文献   
16.
A study of intravenous (i.v.) cannula usage for medical emergencies admitted to hospitals in the Newham Health District was undertaken during two defined periods (24 and 35 days). Almost half the cannulas inserted (47%) were not flushed following an initial bolus injection of heparinized saline. The duration that cannulas remained in a vein ranged from 24 hours to 8 days (median 2 days) and inflammation around the cannula site was related to the length of time since insertion but unrelated to whether the cannula was flushed regularly or to the type of fluid used. Our findings indicate a substantial wastage of i.v. cannulas due to difficulties with insertion and suggest that isotonic saline, without heparin, is effective in maintaining cannula patency for 48 hours. It is concluded that these findings are not unique to the Newham Health District and worthwhile financial savings should be achieved throughout the NHS if clinicians reconsider the indications and use of i.v. cannulas for their patients.  相似文献   
17.

Background  

Traumatic perforation of the distal oesophagus due to blunt trauma is a very rare condition and is still associated with a significant morbidity and mortality. This is further exacerbated by delayed diagnosis and management as symptoms and signs are often masked by or ascribed to more common blunt thoracic injuries.  相似文献   
18.
In this study the deoxyuridine suppression test (dUST) was performed on isolated rat colonocytes to establish its value as an indicator of folate status in the colonic epithelium. [3H]thymidine incorporation into DNA was suppressed greater than 90% by deoxyuridine (dU) concentrations greater than 2.5 mumol/L. Preincubation of cells with 5-fluorouracil (1-100 mumol/L) but not methotrexate (10-100 mumol/L) resulted in a significant decrease in the degree of suppression. The dUST performed on colonocytes from folate-deficient animals displayed less suppression than on colonocytes from folate-replete animals (P less than 0.05). The abnormal degree of suppression was corrected by adding 100 mumol folinic acid/L. There was a negative correlation between the degree of suppression and the folate concentration of the colonic epithelium (P less than 0.001). These data indicate that the dUST is useful for detecting folate deficiency in the colonic epithelium and may therefore be valuable in assessing a deficiency state localized to that epithelium.  相似文献   
19.
20.
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