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   195259篇
  免费   3988篇
  国内免费   440篇
耳鼻咽喉   2782篇
儿科学   7437篇
妇产科学   5890篇
基础医学   25348篇
口腔科学   5786篇
临床医学   15081篇
内科学   34880篇
皮肤病学   4507篇
神经病学   11674篇
特种医学   10659篇
外国民族医学   97篇
外科学   29244篇
综合类   1088篇
一般理论   2篇
预防医学   16607篇
眼科学   4298篇
药学   13674篇
  2篇
中国医学   147篇
肿瘤学   10484篇
  2018年   3488篇
  2017年   3861篇
  2016年   3164篇
  2015年   4818篇
  2014年   4246篇
  2013年   3328篇
  2012年   9777篇
  2011年   4651篇
  2010年   2147篇
  2009年   3804篇
  2008年   2056篇
  2007年   2791篇
  2006年   3065篇
  2005年   11201篇
  2004年   12706篇
  2003年   8261篇
  2002年   3505篇
  2001年   4345篇
  2000年   1715篇
  1999年   5842篇
  1998年   515篇
  1996年   389篇
  1992年   6876篇
  1991年   7111篇
  1990年   7357篇
  1989年   6952篇
  1988年   6484篇
  1987年   6242篇
  1986年   5975篇
  1985年   5263篇
  1984年   3606篇
  1983年   2938篇
  1982年   1026篇
  1981年   791篇
  1980年   856篇
  1979年   3851篇
  1978年   2390篇
  1977年   1805篇
  1976年   1582篇
  1975年   2493篇
  1974年   3134篇
  1973年   2764篇
  1972年   2778篇
  1971年   2765篇
  1970年   2572篇
  1969年   2478篇
  1968年   2255篇
  1967年   2188篇
  1966年   1919篇
  1965年   1142篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
PURPOSE: The purpose to clarify what kind of managerial challenges employees experience regarding organisational justice in hospitals. DESIGN/METHODOLOGY/APPROACH: This exploratory study of 8,971 employees working in 14 hospitals and examines the concept of organisational justice in management with qualitative and quantitative methods. FINDINGS: An inductive content analysis of the comments revealed five integrative frames describing challenges in hospital management at respondents' workplaces. These frames should be regarded as major managerial challenges in hospitals. These findings illustrate important antecedents of organisational justice and suggest that work units tend to share the same perceptions of justice. They also reveal that individually produced comments reflect collective experiences in organisational justice. Further, the results indicate that problems in management and policies are often experienced in a complex way, and people making justice judgements do not separate procedural and interactional factors. RESEARCH LIMITATIONS/IMPLICATIONS: Although the commentators producing qualitative data represented many organisational hierarchy levels, the results should not be generalised to apply to horizontal, informal social relationships. PRACTICAL IMPLICATIONS: This paper gives useful information regarding challenges in human resources management in hospitals. ORIGINALITY/VALUE: The paper suggests that people making fairness judgements do not make a distinction between procedural and interpersonal factors. Instead, they use any information available to judge the righteousness of the management events. This paper serves to guide hospital managers towards a better understanding of the importance of organisational justice and its collective nature.  相似文献   
113.
In 50 children, 4 months to 12 years of age, with minor head trauma non-target visual event-related potentials were performed and compared to a second registration of the potentials some months later. On following-up there was a clear tendency for a relative improvement of the latencies of the endogenous potentials. In this way non-target visual event-related potentials proved to be of value in the investigation of mental impairment in early childhood.  相似文献   
114.
On the basis of data showing a bimodal distribution of values for extracellular pH (pHe), and a discontinuous delta PCO2/delta lactate relationship, Kraig et al. (1986) proposed that H+ is grossly compartmentalized between neurons and glia in the ischemic brain. We measured delta pHe during ischemia, varying ischemic lactate contents between 9 and 38 mmol kg-1. No bimodal distribution was found, but delta pHe varied linearly with lactate content. Because we have also failed to record a discontinuous delta PCO2/delta lactate relationship, we conclude that major compartmentation of H+ does not occur during ischemia.  相似文献   
115.
116.
Trypsin and Zymosan induce an increase in respiration activity of cultivated endothelial cells. These effects are not due to the production of oxygen radicals. The effect of trypsin will be explained by interfering with the cellular homeostasis of calcium. The stimulated respiration after incubation with zymosan may be connected with the increased phagocytosis.  相似文献   
117.
32nd Annual Meeting of the Scandinavian Society for Psychopharmacology Copenhagen, Denmark April 10–12, 1991 Abstracts  相似文献   
118.
Synaptic contacts between growth hormone-releasing hormone (GHRH)- and somatostatin-containing neurons were demonstrated in the rat hypothalamus by a double-staining immunocytochemical method at the electron microscopic level. Somatostatin-immunoreactive nerve terminals synapse on GHRH-positive dendrites and cell bodies in the arcuate nucleus. A fine network of GHRH-immunopositive nerve terminals was observed at the light microscopic level in the rostral part of the periventricular nucleus and in the dorsal part of the arcuate nucleus around somatostatin-containing neuronal elements. With the electron microscope synaptic contact between GHRH-containing nerve terminals and somatostatin-containing dendrites are demonstrated. The reciprocal innervation between GHRH- and somatostatin-containing neurons that project to the median eminence and regulate growth hormone secretion must allow them to coordinate their activities.  相似文献   
119.
Both macrophages and NK cells have been suggested to play a role in recognizing and eliminating early, in situ neoplasms. Therefore we studied the effect of inhibitors of macrophage and/or NK cell function on the take of transplantable spontaneous murine tumors in syngeneic mice. The treatment of animals with trypan blue, a selective inhibitor of macrophage function, decreased considerably the period of latency of BSP3 adenocarcinoma; however, it did not increase the take of SP4, SP82 and SP84 adenocarcinomas. The treatment of recipients with neutral red, a selective inhibitor of NK cell function, enhanced the take of SP4 adenocarcinoma. The treatment of mice with agents depressing both macrophage and NK cell function (silica or carrageenan) decreased the both macrophage and NK cell function (silica or carrageenan) decreased the period of latency and/or increased the take of SP4, SP82 and SP84 adenocarcinomas. Carrageenan or a combined treatment with both trypan blue and neutral red also enhanced the take of BaF1, a benzo(a)pyrene-induced fibrosarcoma. We concluded that both macrophages and NK cells may function as effector cells of an antitumoral surveillance system.  相似文献   
120.
The sequence of structural changes involved in postnatal photoreceptor differentiation, maturation and early degeneration was studied in young Abyssinian cats and kittens with hereditary rod-cone degeneration and compared to maturation in normal controls. In affected cats the earliest change seen was disorientation of outer segment discs in the majority of the rods, while other rods appeared to develop and mature normally. Such disorientation of discs (at oblique angles or parallel to the longitudinal axis of the outer segment, or whorls of discs) is considered as 'immaturity', since controls also showed a substantial number of disoriented rod outer segment discs at this young age. At postnatal day 35 the difference between affected animals and controls was marked with a high frequency of immature appearing rod outer segment discs in affected animals, while all rod outer segment discs were adult-like and arranged in an orderly manner in controls. Cones seemed unaffected at this age. More severe changes in affected rod outer segments in the form of disintegration of discs (vacuolization and clumping of disc material, or formation of debris), which we consider to represent degeneration, were first observed at the time when retinal maturation normally occurs in the cat, i.e. 150 days postnatally. Subsequently a drop-out of rods was seen, primarily of rods with disoriented and disintegrated outer segment discs, followed by a slow, progressive degeneration of rods that had developed and matured normally. Cones appeared normal during the time of retinal development and maturation and it was not until the age of 2-3 years (Narfstr?m and Nilsson, 1986, Incest. Ophthalmol, Vis. Sci. 27, 1569-76) that degenerative changes were seen also in cones.  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