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   711079篇
  免费   49097篇
  国内免费   1337篇
耳鼻咽喉   9207篇
儿科学   23308篇
妇产科学   17686篇
基础医学   110954篇
口腔科学   19999篇
临床医学   64119篇
内科学   135869篇
皮肤病学   16201篇
神经病学   49666篇
特种医学   25871篇
外国民族医学   76篇
外科学   105338篇
综合类   14875篇
现状与发展   2篇
一般理论   161篇
预防医学   51641篇
眼科学   16342篇
药学   54314篇
  3篇
中国医学   2365篇
肿瘤学   43516篇
  2021年   5508篇
  2018年   7947篇
  2017年   6165篇
  2016年   6890篇
  2015年   7639篇
  2014年   10388篇
  2013年   15523篇
  2012年   20744篇
  2011年   21733篇
  2010年   12867篇
  2009年   12085篇
  2008年   20238篇
  2007年   21787篇
  2006年   22215篇
  2005年   20739篇
  2004年   20235篇
  2003年   19230篇
  2002年   18707篇
  2001年   36511篇
  2000年   37096篇
  1999年   30552篇
  1998年   7944篇
  1997年   6726篇
  1996年   7010篇
  1995年   6663篇
  1994年   6144篇
  1993年   5625篇
  1992年   23089篇
  1991年   23027篇
  1990年   22415篇
  1989年   22168篇
  1988年   20117篇
  1987年   19497篇
  1986年   18545篇
  1985年   17363篇
  1984年   12740篇
  1983年   10781篇
  1982年   5940篇
  1979年   11551篇
  1978年   8146篇
  1977年   6853篇
  1976年   6602篇
  1975年   7280篇
  1974年   8511篇
  1973年   8160篇
  1972年   7665篇
  1971年   7144篇
  1970年   6895篇
  1969年   6328篇
  1968年   5793篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Endogenous opioids are present in neurons of the vagus and the intrinsic nervous system and they are colocalized with gastrin in antral G-cells. This raises the possibility that endogenous opioids modulate gastrin release. Stimulation of both cervical vagi (10V, 5Hz, 5ms) elicited an increase of arterial plasma gastrin levels at intragastric pH7 or pH2. The response at pH2 was 30% of that at luminal pH7. Atropine reduced vagally stimulated gastrin levels substantially. At luminal pH2 the small residual noncholinergic response was mediated neither by adrenergic mechanisms nor by endogenous opioids. At luminal pH 7 adrenergic blockade with phentolamine and propranolol reduced vagally stimulated gastrin by 60%. In the presence of atropine adrenergic blockade elicited only a small inhibitory effect suggesting that vagal activation of adrenergic mechanisms depends on atropine-sensitive cholinergic pathways. Blockade of opiate receptors by naloxone had no effect on vagal gastrin release, however, the noncholinergic gastrin response was reduced significantly by naloxone, suggesting that cholinergic mechanisms normally restrain activation of endogenous opioids during vagal stimulation. Naloxone had no effect on the noncholinergic, nonadrenergic stimulation of gastrin levels. These data suggest that endogenous opioids can contribute to vagal gastrin release provided the cholinergic restraint is blocked and adrenergic mechanisms stimulate endogenous opioids. In conclusion a major role of endogenous opioids in the regulation of vagal gastrin release can not be detected.  相似文献   
132.
The article presents part of the results of a Federal German investigation of psychiatric confinement in cases of delinquency in accordance with German law. Among the 674 inmates whose case history could be included in the investigation, there was a predominance of alcohol dependence in two-thirds of them. Confinement occurred mostly only after addiction and delinquencies had been going on for a long time. In more than one-half of the patients no attempt had previously been made to treat and manage their alcohol addiction. Every fourth patient is confined without first consulting a psychiatric expert. Basing on sociobiographic characteristics it is possible to form two contrasting groups of patients: a smaller group where addiction has set in early and delinquency at a late stage, and a larger one with early onset of delinquency developing parallel to the abuse of alcohol. This leads to conclusions with regard to the development of specific treatment guidelines.  相似文献   
133.
134.
135.
10 patients with CLL and 2 with CML were treated with gradually increasing doses of 1 alpha(OH)D3, up to 4 micrograms daily during 6 wk. 3 patients with preleukemia and 1 with myelofibrosis were treated with 2 micrograms daily of 1 alpha(OH)D3 for a prolonged period up to 17 wk. The treatment with 1 alpha (OH)D3 did not result in changes of disease parameters in any of the patients under study. Receptor studies for 1,25(OH)2D3 were performed in 8 CLL patients and revealed only 1 patient with increased specific receptor binding capacity. The maximum tolerable dose of 1 alpha(OH)D3 varied individually, but was in the range of 2-4 micrograms daily.  相似文献   
136.
Biliopancreatic diversion is a very effective method for weight reduction. In some instances it is too effective and needs to be revised.  相似文献   
137.
138.
In 1983, 1623 primary and secondary schoolchildren took part in a health survey which was organized by the Busselton Population Studies Group. Age, sex, weight, height and country of birth were recorded for each child. Where possible, the country of birth of parents and the occupation of the father were extracted from previous Busselton surveys of adults. Compared with Perth schoolchildren, the difference in the attained weight and height of Busselton children at any age was small. This was so even though the two communities differ in location (rural compared with metropolitan), in ethnic origin (mainly British compared with diverse origins) and, probably, in social-rank distribution. Data from the two communities showed that a similar small secular increase in height had occurred since 1970/1971. This increase averaged at 1.2 cm for children at each year of age in Busselton and 1.5 cm to 1.6 cm for children in Perth.  相似文献   
139.
140.
A novel approach for modelling the biological activity of organic molecules, which requires simultaneous consideration of the influence of all factors (topological, steric, hydrophobic, and electronic) that determine the bioactivity, is used to study the interaction of a series of benzoates with anti-p-(p'-azophenylazo)benzoate antibody. The results obtained suggest that this biological interaction proceeds by a two-step stereospecific mechanism. The first step requires a geometrical correspondence between the benzoates and the cavity in the biomacromolecule, which enables the pharmacophore to come into close contact with the receptor. The second step is the orbitally controlled electronic interaction between the active parts of the benzoates and the antibody. The electronic interaction results from pi-charge transfer from the pharmacophore to the biomacromolecule and from the formation of pi-complexes. A proposed mathematical model for this biological interaction exhibits some statistical advantages over existing models.  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