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   1339031篇
  免费   112543篇
  国内免费   6371篇
耳鼻咽喉   16708篇
儿科学   43019篇
妇产科学   36556篇
基础医学   183650篇
口腔科学   36276篇
临床医学   120707篇
内科学   278677篇
皮肤病学   31898篇
神经病学   110733篇
特种医学   55536篇
外国民族医学   274篇
外科学   210402篇
综合类   31533篇
现状与发展   2篇
一般理论   414篇
预防医学   106654篇
眼科学   28087篇
药学   93722篇
  5篇
中国医学   2228篇
肿瘤学   70864篇
  2018年   13389篇
  2017年   10639篇
  2016年   12807篇
  2015年   14301篇
  2014年   19975篇
  2013年   29768篇
  2012年   36290篇
  2011年   38944篇
  2010年   24394篇
  2009年   23919篇
  2008年   36390篇
  2007年   38800篇
  2006年   39931篇
  2005年   38515篇
  2004年   36751篇
  2003年   35837篇
  2002年   33849篇
  2001年   66068篇
  2000年   67936篇
  1999年   56600篇
  1998年   16727篇
  1997年   15018篇
  1996年   16015篇
  1995年   16236篇
  1994年   15102篇
  1993年   14157篇
  1992年   47101篇
  1991年   45758篇
  1990年   43975篇
  1989年   41821篇
  1988年   38771篇
  1987年   38087篇
  1986年   35861篇
  1985年   34641篇
  1984年   26364篇
  1983年   22113篇
  1982年   13848篇
  1981年   12448篇
  1980年   11718篇
  1979年   23549篇
  1978年   17075篇
  1977年   14385篇
  1976年   13182篇
  1975年   13722篇
  1974年   16093篇
  1973年   15397篇
  1972年   14173篇
  1971年   13036篇
  1970年   11880篇
  1969年   11101篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Torsion of noncircular beams results in warping of each cross section. When noncircular cross sections are constrained to remain plane, the resulting shear stress distribution is different from what Saint Venant torsion (with warping) would predict. This has practical implications to the stress analysis of plated long bones subjected to torsional loadings. Analyses in which warping is not allowed predict incorrect stress fields in the plate and bone and overpredict the amount of stress shielding associated with fracture plate fixation.  相似文献   
992.
Diabetes mellitus has deleterious effects on the immune system which may lead to infection that is more serious and difficult to treat. Fifteen diabetic patients with acute bacterial sinusitis are reviewed. Diabetic pathophysiology and its relationship to infection are discussed. A protocol for treatment is outlined, with emphasis on the importance of intravenous antibiotics.  相似文献   
993.
Psychiatric morbidity in Hobart's dependent aged   总被引:1,自引:0,他引:1  
Psychiatric morbidity in the dependent aged was studied in the elderly population of Hobart's nursing homes and long-stay hospitals. Only patients with home addresses in Hobart and who were admitted for the first time aged 70 years or over were included. Three hundred and twelve persons were interviewed with a standard interview, and an informant was interviewed when appropriate. The medical records were searched for diagnoses and drug treatments. Physical disability was rated on an ad hoc scale. Comparisons were made of the prevalence of dementia, depression and anxiety in different types of unit, and between these and two domiciliary samples, one of which received domiciliary nursing services (n = 100) and the other not (n = 100). The differential use of institutions by men and women, and a possible sex difference in the prevalence of dementia is discussed.  相似文献   
994.
Four cases of compulsive hoarding are described, all sharing the following characteristics: (1) onset in the twenties, (2) preoccupation with hoarding to the exclusion of work and family, (3) diminished insight, (4) little interest in receiving treatment, (5) no attempt to curb their compulsion. They do not show clear psychotic features. The implications of these characteristics for the diagnosis of hoarding are discussed.  相似文献   
995.
996.
997.
The postnatal development of soma size and cytochrome oxidase activity was examined in the perigeniculate nucleus (PGN) and reticular nucleus of the thalamus (RNT). Neurons in the PGN and RNT exhibited a rapid increase in soma size between 2 and 4 weeks of age. During this period of cell growth there is an increase in the intensity of cytochrome oxidase staining within the cell body. Cells in both the PGN and RNT decrease in size after 4 weeks of age, and become very fusiform in shape. During this postnatal period, there is also a shift in cytochrome oxidase staining from the cell body to the dendrites.  相似文献   
998.
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   
999.
1000.
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