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   24537篇
  免费   2531篇
  国内免费   23篇
耳鼻咽喉   225篇
儿科学   703篇
妇产科学   592篇
基础医学   3359篇
口腔科学   607篇
临床医学   2890篇
内科学   5066篇
皮肤病学   353篇
神经病学   2369篇
特种医学   786篇
外科学   3226篇
综合类   588篇
一般理论   15篇
预防医学   2538篇
眼科学   453篇
药学   2117篇
  1篇
中国医学   29篇
肿瘤学   1174篇
  2021年   350篇
  2020年   202篇
  2019年   353篇
  2018年   436篇
  2017年   343篇
  2016年   318篇
  2015年   372篇
  2014年   519篇
  2013年   774篇
  2012年   1119篇
  2011年   1157篇
  2010年   669篇
  2009年   560篇
  2008年   1004篇
  2007年   1169篇
  2006年   1090篇
  2005年   1129篇
  2004年   999篇
  2003年   1068篇
  2002年   956篇
  2001年   689篇
  2000年   693篇
  1999年   599篇
  1998年   291篇
  1997年   236篇
  1995年   254篇
  1994年   226篇
  1993年   207篇
  1992年   517篇
  1991年   480篇
  1990年   462篇
  1989年   457篇
  1988年   416篇
  1987年   422篇
  1986年   374篇
  1985年   435篇
  1984年   374篇
  1983年   296篇
  1982年   283篇
  1981年   233篇
  1980年   236篇
  1979年   344篇
  1978年   293篇
  1977年   208篇
  1976年   241篇
  1975年   211篇
  1974年   272篇
  1973年   284篇
  1972年   231篇
  1971年   211篇
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
61.
62.
63.
64.
Retrospective analysis of necropsy findings of 705 woodchucks was performed to determine the prevalence and morphology of immune-mediated glomerulonephritis, its relationship to woodchuck hepatitis virus (WHV) infection, and the presence of major WHV antigens. Twenty-six woodchucks had glomerular lesions. Renal tissue of the 26 animals was evaluated histologically and immunohistochemically for immune-mediated glomerulonephritis. Of these 26 animals, immune-mediated glomerulonephritis was diagnosed in six, all of which were chronic WHV carriers. Membranous glomerulonephritis was identified in three animals, two of which also had mesangial proliferation. Host immunoglobulin was present within the mesangium and along capillary loops in all three. Woodchuck hepatitis virus core antigen (WHcAg) was present along capillary loops of two of these animals, one membranous and one mixed, and in the mesangium of all three. Woodchuck hepatitis virus surface antigen (WHsAg) deposition was similar to WHcAg deposition but was only present along capillaries in those animals with mixed nephritis. The remaining three animals had mesangial proliferation. WHsAg and host immunoglobulin deposition were predominately mesangial; WHcAg was not detected. Transmission electron microscopy showed thickening of the capillary loop basement membranes and subepithelial electron-dense deposits in animal one, and deposits in the mesangium in animal six.  相似文献   
65.
The pH and acid content of 63 glucose-based solutions was measured up to eight years after their expiry. The pH ranged from 2.27 to 4.33. Newly manufactured solutions with 5 per cent or less of glucose which were packaged in plastic bags contained in the order of 0.01 mEq/L of acid per gram of glucose. Solutions with higher glucose concentrations had lower pH and greater acid. As solutions in bags became older, pH decreased and acid increased. In contrast, 25 per cent and 50 per cent glucose solutions in glass containers were much less acid and showed only slight changes with age in pH or acid. The greater rate of acid increase in glucose solutions in plastic bags may be due to the bags being permeable to oxygen and thus allowing slow oxidation of the glucose.  相似文献   
66.
Community surveys are increasingly being used as a method of collecting health and lifestyle data. This report describes the use of a simple question on hearing difficulties within such a survey. A systematic sample of 2.5% of the electoral register of the four Parliamentary constituencies of Cardiff, Wales, was drawn. Of the 5145 individuals in the sample, 83% responded. Age and social class explained much of the variability in reported hearing difficulties. A recent fall and cigarette consumption were associated with hearing problems, but the contribution of alcohol consumption while potentially important did not reach statistical significance. This self-administered community survey provided hearing data which are consistent with other specialized studies and is a viable route for the assessment of community needs.  相似文献   
67.
68.
69.
Thirteen morbidly obese individuals were studied prospectively for 1 year after vertical banded gastroplasty (VBG) to determine the relationships between energy balance equation parameters and excess weight loss. The measured energy expenditure (MEE), as determined by indirect calorimetry, was not correlated with weight loss. However, when this parameter was expressed as a ratio to the predicted energy expenditure (PEE), the ratio was significantly correlated with the postoperative excess weight loss at 2, 6, and 12 months. The mean daily energy intake after the VBG was 2715 +/- 865 kJ. The postoperative energy intake was not correlated with the excess weight loss. Diet-induced thermogenesis was studied in eight patients. The mean diet-induced thermogenesis was 10.31% +/- 13.92%. The diet-induced thermogenesis was not correlated with the postoperative excess weight loss. The preliminary findings of this trial suggest that the MEE/PEE ratio is useful in predicting excess weight loss after VBG.  相似文献   
70.
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