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   135933篇
  免费   9431篇
  国内免费   630篇
耳鼻咽喉   1651篇
儿科学   3418篇
妇产科学   2444篇
基础医学   17377篇
口腔科学   2896篇
临床医学   13296篇
内科学   27981篇
皮肤病学   1751篇
神经病学   11946篇
特种医学   5396篇
外科学   21817篇
综合类   1916篇
现状与发展   1篇
一般理论   173篇
预防医学   12397篇
眼科学   2916篇
药学   9600篇
  2篇
中国医学   179篇
肿瘤学   8837篇
  2023年   671篇
  2022年   1048篇
  2021年   2571篇
  2020年   1467篇
  2019年   2396篇
  2018年   2924篇
  2017年   2112篇
  2016年   2229篇
  2015年   2714篇
  2014年   4015篇
  2013年   6055篇
  2012年   8865篇
  2011年   9438篇
  2010年   5253篇
  2009年   4806篇
  2008年   8382篇
  2007年   8985篇
  2006年   8558篇
  2005年   8712篇
  2004年   8370篇
  2003年   7867篇
  2002年   7678篇
  2001年   1275篇
  2000年   1049篇
  1999年   1396篇
  1998年   1626篇
  1997年   1303篇
  1996年   1251篇
  1995年   1216篇
  1994年   1031篇
  1993年   1004篇
  1992年   839篇
  1991年   863篇
  1990年   753篇
  1989年   731篇
  1988年   753篇
  1987年   737篇
  1986年   759篇
  1985年   835篇
  1984年   907篇
  1983年   867篇
  1982年   1130篇
  1981年   1156篇
  1980年   964篇
  1979年   631篇
  1978年   668篇
  1977年   597篇
  1976年   519篇
  1975年   469篇
  1974年   471篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
Unravelling the cause of a neutropenia poses a complex diagnostic challenge. The differential diagnosis ranges from life threatening disease to transient benign causes of little clinical significance. This review offers a practical guide to investigating the neutropenic child, and highlights features that merit specialist referral. Therapeutic options, the role of long term follow up, and the complications of severe chronic neutropenia are considered.  相似文献   
103.
AMPA receptor potentiators enhance AMPA receptor-mediated glutamatergic neurotransmission and may have therapeutic potential as cognitive enhancers or antidepressants. The anatomical basis for the action of AMPA receptor potentiators is unknown. The aim of this study was to determine the effects of the biarylpropylsulfonamide AMPA receptor potentiator, LY404187 (0.05 to 5 mg/kg subcutaneously), upon cerebral glucose utilization and c-fos expression using 14C-2-deoxglucose autoradiography and c-fos immunocytochemistry. LY404187 (0.5 mg/kg) produced significant elevations in glucose utilization in 28 of the 52 anatomical regions analyzed, which included rostral neocortical areas and the hippocampus, as well the dorsal raphe nucleus, lateral habenula, and locus coeruleus. No significant decreases in glucose utilization were observed in any region after LY404187 administration. The increases in glucose utilization with LY404187 (0.5 mg/kg) were blocked by pretreatment with the AMPA receptor antagonist LY293558 (25 mg/kg), indicating that LY404187 acts through AMPA receptor-mediated mechanisms. LY404187 (0.5 mg/kg) also produced increases in c-fos immunoreactivity in the cortex, locus coeruleus, and the dorsal raphe nucleus. These studies demonstrate neuronal activation in key brain areas that are associated with memory processes and thus provide an anatomical basis for the cognitive enhancing effects of AMPA receptor potentiators.  相似文献   
104.
The hairline and frontal hair volume are frequently overlooked aspects of attractive facial proportion and overall facial aesthetics. The author contends that patient benefit from hair restoration surgery is significant, and these procedures should be routinely considered as part of a complete facial rejuvenation.  相似文献   
105.
106.
Health education campaigns which utilise the mass media generally employ advertising techniques. Television and print media are considered more influential, with radio being primarily used for awareness raising and campaign support messages. There is relatively little research into the effectiveness of radio talkback programs in promoting health or reducing illness. This paper argues a case for health and welfare professionals to utilise talkback radio as part of their health promotion activities.  相似文献   
107.
An endogenous ouabain-like substance (OLS) plays a critical role in the etiology of experimental models of human hypertension induced by a high salt diet. Early on, evidence for a role of this Na, K-ATPase inhibitor in blood pressure regulation was provided mainly by correlations of blood pressure with the levels of circulating Na, K-ATPase inhibitor. However, over the past decade, numerous studies have shown that endogenous Na pump inhibitors in the brain mediate salt-dependent hypertension in a variety of experimental models, including Dahl salt-sensitive (Dahl-S) and spontaneously hypertensive (SHR) rats on a high-salt diet. Other forms of hypertension that are known to be mediated by endogenous ouabain-like substances include steroid/salt- (e.g., DOCA-salt) and ACTH-induced hypertension. Even when exogenous ouabain is peripherally administered and/or the plasma ouabain/OLS level is increased in rats, the resulting hypertension is of CNS origin. After peripheral ouabain administration, ouabain levels increase in the plasma and the inhibitor subsequently accumulates in the brain. The ensuing hypertension is abolished by the intracerebroventricular (icv) administration of an anti-ouabain antibody (but not by the same antibody dose given iv), by discrete excitotoxic lesions in the brain or by ganglionic blockade, demonstrating that the response is neurally mediated. The pressor response to stimuli that increase the brain OLS (high salt diet, icv sodium) or to icv ouabain is abolished by icv losartan, demonstrating that the brain OLS activates the brain renin-angiotensin system (RAS) downstream. There are three isoforms of the catalytic alpha subunit of the Na, K-ATPase in the brain and cardiovascular system (alpha1, alpha2 and alpha3), but it is not known which brain isoform(s) mediate the hypertensive effects of circulating/CNS ouabain. Preliminary studies in gene-targeted mice suggest that the alpha2 isoform plays a critical role.  相似文献   
108.
109.
110.
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