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   16843篇
  免费   1102篇
  国内免费   310篇
耳鼻咽喉   82篇
儿科学   457篇
妇产科学   171篇
基础医学   2923篇
口腔科学   427篇
临床医学   1252篇
内科学   2480篇
皮肤病学   258篇
神经病学   1294篇
特种医学   529篇
外国民族医学   3篇
外科学   1331篇
综合类   1538篇
现状与发展   2篇
预防医学   992篇
眼科学   128篇
药学   2163篇
  2篇
中国医学   601篇
肿瘤学   1622篇
  2023年   173篇
  2022年   341篇
  2021年   390篇
  2020年   368篇
  2019年   487篇
  2018年   524篇
  2017年   456篇
  2016年   486篇
  2015年   533篇
  2014年   943篇
  2013年   1156篇
  2012年   824篇
  2011年   1076篇
  2010年   721篇
  2009年   787篇
  2008年   771篇
  2007年   810篇
  2006年   751篇
  2005年   675篇
  2004年   650篇
  2003年   527篇
  2002年   409篇
  2001年   412篇
  2000年   373篇
  1999年   316篇
  1998年   265篇
  1997年   269篇
  1996年   207篇
  1995年   219篇
  1994年   201篇
  1993年   169篇
  1992年   132篇
  1991年   114篇
  1990年   139篇
  1989年   87篇
  1988年   77篇
  1987年   82篇
  1986年   66篇
  1985年   143篇
  1984年   194篇
  1983年   98篇
  1982年   135篇
  1981年   125篇
  1980年   95篇
  1979年   90篇
  1978年   65篇
  1977年   53篇
  1976年   61篇
  1975年   58篇
  1974年   60篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
31.
Decreased plasma levels of apolipoprotein A-I (apo A-I) and increased plasma levels of apolipoprotein B (apo B) have been shown to correlate with increased risk of atherosclerosis. While many studies have investigated the plasma levels of these apolipoproteins with regard to their value as predictors of cardiovascular disease, comparatively little is known about their precise tissue localization in atherosclerotic plaques. The purpose of this study was to determine the tissue localization of apo A-I and apo B in atherosclerotic segments of human carotid arteries through the use of immunohistochemical techniques. With tissue samples obtained from surgery and autopsy, apo A-I and apo B were found to be present in atherosclerotic plaques and absent in normal arterial tissue. In the plaques, both apo A-I and apo B were found extracellularly, primarily in the lipid core, but also in connective tissue. In addition, both apo A-I and apo B were found intracellularly in foam cells. This similar intracellular and extracellular distribution of apo A-I and apo B was unexpected, in view of their differing associations with atherosclerosis.  相似文献   
32.
The effect of propranolol inhalation on sensitivity to methacholine inhalation was studied in normal and allergic rhinitis subjects to determine whether beta adrenergic blockade alters sensitivity to mediators in nonasthmatic atopic individuals. A partial beta adrenergic blockade is suggested as being instrumental in asthma. Hay fever patients studied showed similar effects and also developed asthma for the first time.  相似文献   
33.
The Usher syndromes are genetically distinct disorders which share specific phenotypic characteristics. This paper describes a set of clinical criteria recommended for the diagnosis of Usher syndrome type I and Usher syndrome type II. These criteria have been adopted by the Usher Syndrome Consortium and are used in studies reported by members of this Consortium. © 1994 Wiley-Liss, Inc.  相似文献   
34.
UV-light-induced signal cascades and skin aging   总被引:12,自引:0,他引:12  
  相似文献   
35.
Heritable dentin defects have been divided into 2 main categories: dentinogenesis imperfecta (DI) and dentin dysplasia (DD). Recent studies have shown that they share many features in common. Of the connective tissue diseases, only osteogenesis imperfecta (OI) has been linked to these disorders. So far, no definitive relation between the type of OI and the dental involvement can be established. Familial occurrence of DI with OI cannot be comprehensively explained by mutations in type I collagen genes. No information about the gene defects in DD is available. At the ultrastructural level, the organization of the normally cross-striated collagen fibers in the dentin matrix varies markedly in patients affected by DI.  相似文献   
36.
During three different motor tasks of finger, wrist and arm movements on either side, 80 pyramidal tract neuron (PTN) activities were recorded in the monkey motor cortex. They were divided into three groups; PTNs related to controlateral movement (contra-PTNs), those related to ipsilateral movementt lateral movement (bilaterai-PTNs) and those related to ipsilateral movement (ipsi-PTNs). The latency histogram of the antidromic activation was similar for contra-PTNs as well as ipsi- and bilateral-PTNs in the fast PTN group, but most of slow PTNs appeared among contra-PTNs. Intracortical microstimulation (ICMS) was delivered to correlate muscular contraction with PTN acticity. Most of slow PTNs were related to proximal muscular contraction and PTNs related to proximal muscles appeared more in ipsi- and bilateral-PTNs than in contra-PTNs.  相似文献   
37.
A new high yield 123I radioiodination (97%), based on the Cu(I) assisted isotopic exchange in an ethanol water mixture, of 15(p-I-phenyl)-9 methyl pentadecanoic acid, a potential myocardial tracer, is proposed. The method allows a true kit preparation of radioiodinated phenyl fatty acids for a substrate concentration of ±10-6 moles. High specific activities (>0.1 mCi/IDDLE" BORDER="0">g) can be obtained when coupling the labelling method to HPLC purification with an overall radiochemical yield of 75%.  相似文献   
38.
39.
40.
During the past 12 years, ten cases of globoidcell leukodystrophy (GLD) have been followed up: seven of these patients were affected by the late infantile form. The authors point out the clinical aspects and the course of these patients and stress the high frequency of this form of GLD in Sicily.  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