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   52338篇
  免费   2993篇
  国内免费   372篇
耳鼻咽喉   565篇
儿科学   1277篇
妇产科学   1269篇
基础医学   6995篇
口腔科学   3267篇
临床医学   4043篇
内科学   11980篇
皮肤病学   1015篇
神经病学   4681篇
特种医学   1513篇
外国民族医学   1篇
外科学   6937篇
综合类   408篇
一般理论   13篇
预防医学   4240篇
眼科学   684篇
药学   3457篇
中国医学   335篇
肿瘤学   3023篇
  2023年   471篇
  2022年   1073篇
  2021年   1829篇
  2020年   1204篇
  2019年   1485篇
  2018年   1789篇
  2017年   1398篇
  2016年   1488篇
  2015年   1709篇
  2014年   2213篇
  2013年   2650篇
  2012年   4080篇
  2011年   4352篇
  2010年   2344篇
  2009年   2007篇
  2008年   3321篇
  2007年   3186篇
  2006年   2915篇
  2005年   2579篇
  2004年   2406篇
  2003年   2134篇
  2002年   1889篇
  2001年   721篇
  2000年   748篇
  1999年   665篇
  1998年   366篇
  1997年   289篇
  1996年   288篇
  1995年   240篇
  1994年   177篇
  1993年   172篇
  1992年   326篇
  1991年   292篇
  1990年   265篇
  1989年   271篇
  1988年   238篇
  1987年   198篇
  1986年   174篇
  1985年   164篇
  1984年   157篇
  1983年   134篇
  1982年   76篇
  1981年   84篇
  1980年   75篇
  1979年   104篇
  1978年   94篇
  1977年   69篇
  1974年   80篇
  1973年   71篇
  1970年   69篇
排序方式: 共有10000条查询结果,搜索用时 3 毫秒
41.
Japanese encephalitis after a two-week holiday in Bali   总被引:2,自引:0,他引:2  
Japanese encephalitis is described in a 10-year-old girl after a short holiday in Bali. Four days after returning to Australia the patient presented with a high fever, stupor and rapidly-developing focal neurological signs. Recovery occurred gradually over a period of three months and she has returned to school. Japanese encephalitis viral infection was confirmed by a marked rise in specific haemagglutination-inhibition antibodies and the presence of immunoglobulin M antibodies to the flavivirus group. It is important to be aware of the possibility of arboviral infection in patients with encephalitis. In view of the recent outbreaks of Japanese encephalitis in Asia, travellers to the region should be warned to protect themselves from mosquito-bites.  相似文献   
42.
43.
44.
45.
Exposure of isolated rat pancreatic acini to increasing concentrations (10 ng - 800 ng/ml) of toxin B from Clostridium difficile produced a biphasic effect on the rate of secretion of amylase, trypsinogen, and chymotrypsinogen. Whereas doses of toxin B from 10-30 ng/ml increased enzyme secretion by 15-20%, doses between 30 ng and 60 ng/ml showed a regression of this effect, whereafter the rate of secretion of amylase, trypsinogen, and chymotrypsinogen increased with increasing concentrations of the toxin. Toxin B concentration of 800 ng/ml enhanced amylase, trypsinogen and chymotrypsinogen secretion by 119%, 185% and 195%, respectively, when compared with the basal level. Stimulation of enzyme secretion by toxin B was not affected by the presence of either actinomycin-D or cycloheximide, at a concentration which inhibited acinar RNA or protein synthesis by 80-90%. Although toxin B as well as CCK8, carbachol and secretin by themselves caused significant stimulation in amylase, trypsinogen and chymotrypsinogen secretion from isolated pancreatic acini, toxin B together with either CCK8, carbachol or secretin produced no further augmentation in enzyme secretion than what was observed with the secretagogues alone. It is concluded that toxin B of Cl. difficile exerts a direct effect on pancreatic acinar cells as evidenced by stimulation of enzyme secretion.  相似文献   
46.
47.
48.
49.
The purpose of this study was to assess the concentration and binding pattern of zinc, iron, folate and vitamin B12 in milk of Brazilian women of low socioeconomic status giving birth at term or preterm, during early lactation. Protein, fat, total solids and ash concentrations were also determined. Protein and zinc concentrations decreased significantly as lactation proceeded whereas milk fat and folate increased with the lactation period. Total solids, ash, iron and vitamin B12 remained unchanged. Zinc was present mainly in the whey fraction while less than half of the total iron was present in this fraction, with no significant change due to stage of lactation. Unsaturated folate and vitamin B12 binding capacities and percentage of saturation of the folate binding protein increased with the stage of lactation. The vitamin B12 binding protein was highly unsaturated in all samples. There was no significant difference between term and preterm samples in the parameters investigated. Correlation analysis between milk components indicated significant relationships between total solids and fat, total zinc and whey zinc, folate and total folate binding capacity, unsaturated and total folate binding capacity, and unsaturated and total B12 binding capacity. In general, the nutrient concentrations found in this study are in good agreement with published data on milk composition of women from developed countries, with the possible exceptions of folate, which was lower, and iron, which was higher. The correlation of folate concentration with its binding protein found in this work supports the hypothesis of a regulatory role for folate levels in milk exerted by the folate binding protein in the mammary gland.  相似文献   
50.
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