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   124487篇
  免费   6436篇
  国内免费   207篇
耳鼻咽喉   1813篇
儿科学   5361篇
妇产科学   4007篇
基础医学   16943篇
口腔科学   2943篇
临床医学   9236篇
内科学   24187篇
皮肤病学   3501篇
神经病学   9387篇
特种医学   5246篇
外国民族医学   33篇
外科学   20569篇
综合类   1812篇
现状与发展   1篇
一般理论   34篇
预防医学   6392篇
眼科学   3538篇
药学   8850篇
中国医学   478篇
肿瘤学   6799篇
  2021年   1207篇
  2019年   1110篇
  2018年   1372篇
  2017年   1064篇
  2016年   1415篇
  2015年   1567篇
  2014年   2029篇
  2013年   2861篇
  2012年   3858篇
  2011年   3823篇
  2010年   2287篇
  2009年   2222篇
  2008年   3680篇
  2007年   3890篇
  2006年   3970篇
  2005年   4061篇
  2004年   3937篇
  2003年   3800篇
  2002年   3623篇
  2001年   7058篇
  2000年   6992篇
  1999年   5878篇
  1998年   1643篇
  1997年   1565篇
  1996年   1345篇
  1995年   1206篇
  1994年   1096篇
  1993年   1128篇
  1992年   3771篇
  1991年   3581篇
  1990年   3565篇
  1989年   3353篇
  1988年   2991篇
  1987年   2897篇
  1986年   2804篇
  1985年   2623篇
  1984年   1950篇
  1983年   1597篇
  1982年   933篇
  1981年   927篇
  1979年   1823篇
  1978年   1351篇
  1977年   1114篇
  1976年   939篇
  1975年   1180篇
  1974年   1213篇
  1973年   1199篇
  1972年   1043篇
  1971年   975篇
  1970年   880篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
63.
BACKGROUND AND AIMS: Liver surgery is developing with new techniques and treatment modalities. The aim of this study is to describe liver surgery over a long period of time in a country with a public health care system. PATIENTS AND METHOD: A register study including adult patients admitted for liver resection in Sweden (population 8.8 million) selected from the Inpatient Register 1987-99. Additional data were collected from the Swedish Cancer Register and the Cause of Death Register. Analyses of the patients, indications, mortality and causes of death are presented. RESULTS: 2,405 operations were performed (21 per million per year). The most frequent indication was colorectal metastases (27%). The 5-year survival after an operation for primary liver cancer and colorectal liver metastases was 27% and 26%, respectively. CONCLUSIONS: Few patients were admitted for liver operations compared to expected figures. The survival rates are in conformity with those previously published. With an increasing awareness of the relatively favourable prognosis and the introduction of new methods, the volume of liver operations will probably increase in Sweden.  相似文献   
64.
The effects of acute stress exposure upon cholecystokinin (CCK) and substance P (SP) concentrations in discrete hypothalamic regions of the adult male rat brain were studied. Animals were exposed to foot shock stress for periods of 2, 4, 10, 30 or 60 min duration; immediately afterwards they were decapitated; brains were frozen and subsequently microdissected. CCK and SP concentrations were assayed by a specific RIA, as were serum levels of ACTH, corticosterone, PRL, GH, LH and testosterone. Stress had no effect upon SP concentrations in the anterior or posterior parts of the arcuate nucleus (ARC), but led to elevated CCK levels in the posterior ARC following 60 min of exposure. In both the ventromedial and dorsomedial hypothalamic areas, stress induced depletions of both neuropeptides. In the anterior (but not the posterior) portions of the lateral hypothalamic area, CCK and SP concentrations were reduced by stress exposure. These studies demonstrate that discrete hypothalamic CCK and SP neuronal systems are responsive to stress. This suggests that endogenous hypothalamic CCK and SP participate, along with other neurotransmitters/neuromodulators, in the integrated hypothalamic stress response, and mediate stress-neuroendocrine interactions.  相似文献   
65.
Activating effect of substance P on nerve tissue in culture   总被引:1,自引:0,他引:1  
The effect of substance P on organotypic culture of rat sympathetic ganglia and spinal cord was studied. Substance P was able to stimulate the fibre outgrowth from explant, to increase the numbers of glial and fibroblasttypic cells in ganglia growth zone. The effect was observed in the range from 10(-5) to 10(-12) M (for sympathetic ganglia) and from 10(-5) to 10(-14) M (for spinal cord culture). It is suggested that substance P can be used as a nonspecific growth factor for peripheral and central nervous tissue.  相似文献   
66.
67.
At independence in 1961, Tanzania inherited a classic economic structure from Britain. The most immediate aims of the new government included replacing the colonial administration with trained nationals, radical change of the development philosophy and strategies and development of self-reliance in all development sectors. The Arusha Declaration of 1967 was the turning point in Tanzania and achievements in all the sectors can be measured against targets established soon after. This paper examines development in the health sector within the wider national framework.  相似文献   
68.
69.
70.
Renal vascular reactivity in jaundice   总被引:1,自引:0,他引:1  
Obstructive jaundice is associated with a predisposition to hypotension and acute renal failure that may be related to changes in renovascular responsiveness, particularly to norepinephrine (NE). This study was undertaken to investigate changes in vascular response to NE and to determine how these changes are related to prostaglandins. Kidneys from bile duct-ligated (BDL) rabbits (n = 5) were perfused with Krebs' solution at 7.65 ml/min, and the response to varying boluses of NE (0.78 to 6.24 micrograms) was measured as changes in perfusion pressure. When compared with sham-operated control kidneys (n = 8), a significantly blunted response was seen at all doses tested. The NE response was further assessed by measuring force development in mounted segments of main renal arteries (MRAs) (n = 8) and interlobar arteries (ILAs) (n = 6) from BDL rabbits and sham-operated controls (MRA, n = 8; ILA, n = 6). The dose-response curves were significantly depressed in both MRAs and ILAs from BDL animals. In addition, MRAs from sham-operated control animals exhibited decreased response to NE after incubation for 1 hour in jaundiced serum. This attenuated response of MRAs to NE was prevented when indomethacin (5 mg/kg) was given to BDL rabbits before death (n = 9) or when 10(-6)mol/L of indomethacin was added to jaundiced serum during incubation (n = 6). These results indicate that obstructive jaundice induces a decreased vascular contractile response in rabbits to NE and that this effect is mediated by prostaglandins.  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