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   1710050篇
  免费   125085篇
  国内免费   4713篇
耳鼻咽喉   21872篇
儿科学   55781篇
妇产科学   46392篇
基础医学   243003篇
口腔科学   48983篇
临床医学   153322篇
内科学   335828篇
皮肤病学   38813篇
神经病学   131932篇
特种医学   64396篇
外国民族医学   247篇
外科学   258959篇
综合类   41023篇
现状与发展   5篇
一般理论   537篇
预防医学   125233篇
眼科学   40669篇
药学   125111篇
  22篇
中国医学   5212篇
肿瘤学   102508篇
  2021年   13555篇
  2019年   14041篇
  2018年   20469篇
  2017年   15697篇
  2016年   17080篇
  2015年   19637篇
  2014年   27040篇
  2013年   38711篇
  2012年   53807篇
  2011年   56503篇
  2010年   33576篇
  2009年   31300篇
  2008年   52233篇
  2007年   55530篇
  2006年   56024篇
  2005年   53258篇
  2004年   51322篇
  2003年   48717篇
  2002年   46869篇
  2001年   92152篇
  2000年   93922篇
  1999年   77280篇
  1998年   19972篇
  1997年   17494篇
  1996年   17559篇
  1995年   16907篇
  1994年   15395篇
  1993年   14165篇
  1992年   57465篇
  1991年   55346篇
  1990年   53036篇
  1989年   50804篇
  1988年   46186篇
  1987年   44984篇
  1986年   42255篇
  1985年   40015篇
  1984年   29360篇
  1983年   24920篇
  1982年   13903篇
  1979年   25545篇
  1978年   17577篇
  1977年   14914篇
  1976年   13881篇
  1975年   14567篇
  1974年   17635篇
  1973年   16948篇
  1972年   15675篇
  1971年   14457篇
  1970年   13432篇
  1969年   12520篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
943.
944.
945.
946.
947.
This study evaluates the glycine potentiation of anticonvulsant drugs in subcutaneous pentylenetetrazol seizures in rats. Administered alone, glycine (30 or 40 mM/kg, PO) induced no anticonvulsant effect or neurological deficit. Coadministered with anticonvulsants, glycine significantly enhanced the anticonvulsant potency of diazepam and sodium valproate without affecting the neurological deficit induced by the anticonvulsants. Glycine did not significantly alter the anticonvulsant activity of ethosuximide or phenobarbital. These findings indicate a possible glycine-sensitive component in the mechanism of action of diazepam and sodium divalproate in subcutaneous pentylenetetrazol seizures. With the possible exception of sodium valproate, the present study provides little support for a glycine and gamma-aminobutyric acid (GABA) interaction as a mechanism of anticonvulsant activity in SC PTZ seizures. Further studies are required to determine the role of strychnine-sensitive and strychnine-insensitive glycine receptors in this experimental model of absence epilepsy.  相似文献   
948.
The effect of ferritins from horse (FH) and bovine (FB) spleen and murine liver (FM) on the survival rate of CFW mice lethally infected with Escherichia coli (strain 8440-78 K 80/B) was evaluated. Ferritins given intravenously 24 h before intravenous inoculation of bacteria, protected mice most effectively from death due to infection. The effect was dose dependent. At 500 micrograms of ferritin per mouse, the maximum survival rates were 86% (FH), 81% (FM) and 79% (FB), while only 5% of the control mice survived up to the 30th day. The survival rates of animals injected with bovine serum albumin (BSA) and heat-inactivated FB were 8 and 25%, respectively. Intraperitoneal injection of FB was as effective as intravenous in enhancing the resistance of mice against bacteria. These data provide evidence for the beneficial role of tissue ferritins in nonspecific antibacterial resistance.  相似文献   
949.
Benzene is metabolized to one or more hematotoxic species. Saturation of benzene metabolism could limit the production of toxic species. Saturation of phase II enzymes involved in the conjugation of the phenolic metabolites of benzene also could affect the hematotoxicity of benzene. To investigate the latter possibility, we exposed male Swiss mice, via the inhalation route, to various concentrations of benzene for 6 h per day for 5 days. Following termination of the final exposure the mice were killed and the levels of phenylsulfate and phenylglucuronide in the blood determined. Spleen weights were recorded and the number of white blood cells counted. At low benzene exposure concentrations phenylsulfate is the major conjugated form of phenol in the blood. At high exposure concentrations, phenylglucuronide is the predominant species. The reductions in spleen weight and white blood cell numbers correlated with the concentration of phenylsulfate in the blood, but are most probably not causally related.  相似文献   
950.
The aim of this study was to evaluate the public opinion towards the possible replacement of ration cards by cash payment and to investigate the effect of partial termination of food price subsidy programme on food consumption by families from different income brackets. A purposive sample of 300 families from Alexandria Governorates were interviewed to assess the attitude of the consumer towards the possible termination of current food subsidy programme. After one year, during which the subsidy programme was reduced, a follow up sample of 240 were interviewed. The results show that a large proportion of the families prefer the continuation of the current programme (80-81.2%), meanwhile, around 90% of them believed that subsidized foods do not reach the target group. The data show that subsidized meat and poultry are consumed by high income families while frozen subsidized fish was mostly consumed by poor families. The partial termination of the subsidy programme forced the families to reduce their consumption from sugar, tea, oil, and rice. During the second phase of the study. However the results show that high income families were least affected by the partial termination of the subsidy programme.  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