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   706202篇
  免费   50098篇
  国内免费   1296篇
耳鼻咽喉   9191篇
儿科学   23286篇
妇产科学   17678篇
基础医学   110732篇
口腔科学   19984篇
临床医学   64010篇
内科学   134378篇
皮肤病学   16179篇
神经病学   49567篇
特种医学   25841篇
外国民族医学   76篇
外科学   104620篇
综合类   14837篇
现状与发展   2篇
一般理论   163篇
预防医学   51482篇
眼科学   16381篇
药学   54150篇
  3篇
中国医学   2355篇
肿瘤学   42681篇
  2019年   5460篇
  2018年   7882篇
  2017年   6123篇
  2016年   6846篇
  2015年   7573篇
  2014年   10304篇
  2013年   15440篇
  2012年   20579篇
  2011年   21585篇
  2010年   12760篇
  2009年   11969篇
  2008年   20065篇
  2007年   21595篇
  2006年   21993篇
  2005年   20529篇
  2004年   20061篇
  2003年   19028篇
  2002年   18501篇
  2001年   36384篇
  2000年   36953篇
  1999年   30421篇
  1998年   7896篇
  1997年   6690篇
  1996年   6991篇
  1995年   6653篇
  1994年   6117篇
  1993年   5620篇
  1992年   23022篇
  1991年   22978篇
  1990年   22358篇
  1989年   22116篇
  1988年   20084篇
  1987年   19472篇
  1986年   18503篇
  1985年   17340篇
  1984年   12718篇
  1983年   10763篇
  1982年   5946篇
  1979年   11547篇
  1978年   8145篇
  1977年   6847篇
  1976年   6612篇
  1975年   7285篇
  1974年   8518篇
  1973年   8161篇
  1972年   7672篇
  1971年   7140篇
  1970年   6898篇
  1969年   6310篇
  1968年   5791篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
951.
952.
953.
Five hundred and thirty-three women attending a genitourinary medicine clinic underwent concurrent cytology and Chlamydia trachomatis screening using a Cytobrush (Medscand AB). In each case, the same Cytobrush was used to give a sample for direct immunofluorescence and culture. 11.1% of samples were positive by immunofluorescence, while 10.6% were positive by culture. This was a close agreement (Kappa = 0.875). The ability of the same instrument to be used for both cytology and chlamydial screening, where direct immunofluorescence is used for detection of chlamydiae, may allow more widespread screening for chlamydia to be practical.  相似文献   
954.
955.
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   
956.
957.
Lead nitrate administered to noninbred rats with drinking water on the level of IO MAC (0.3 mg/l) during the whole period of gestation lead to the strengthening of hepatotoxic effect of cadmium chloride (7.5 and 15 mg/kg daily by gavage from the 1st to 20th day of gestation), manifest in significant increase of the hepatocytes alteration index, increase of the number of the pyknotic cells of reticuloendothelial system, increase of the degree of dams' liver hepatocytes dystrophy, decrease in the specific volume of megakaryocytes in the liver of their fetuses.  相似文献   
958.
959.
Three high-amylose rice varieties, IR42, IR36, and IR62, with similar chemical composition including amylose content (26.7-27.0%), were cooked under the same conditions and tested for in vitro digestibility as well as blood glucose and insulin responses in healthy human volunteers. The starch-digestion rate and the glycemic and insulin responses were the highest in IR42, followed by IR36 and, then IR62. The differences were not due to unabsorbed carbohydrate but were related to their physicochemical properties, such as gelatinization temperature, minimum cooking time, amylograph consistency, and volume expansion upon cooking. When the three varieties were cooked for their minimum cooking time, they had the same degree of gelatinization and their starch-digestion rates and glycemic responses were similar. We conclude that amylose content alone is not a good predictor of starch-digestion rate or glycemic response. Rice varieties with similar high-amylose contents can differ in physicochemical (gelatinization) properties and this, in turn, can influence starch digestibility and blood glucose response.  相似文献   
960.
In vivo determination of body fat by measuring total body carbon   总被引:2,自引:0,他引:2  
Total body carbon (TBC) is measured in vivo by neutron inelastic scattering. The fast neutrons needed for the irradiation are produced by a miniature deuterium-tritium (D-T) neutron generator. Body fat and protein are the main contributors to TBC. Bone ash and carbohydrates contribute less than 3%. Fat is calculated from TBC after the subtraction of the carbon contributions from protein, bone, and glycogen. The technique was applied to 14 normal volunteers (8 females, 6 males) aged 24-94 y who underwent neutron inelastic scattering and neutron activation measurements for body carbon, nitrogen, and calcium. The initial results agree with other techniques. Unlike models that evaluate body fat by subtracting lean body mass from body weight, the TBC technique is not sensitive to assumptions on the composition of lean body; therefore, it is appropriate for studies of adults of any age and health condition.  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