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   9568篇
  免费   820篇
  国内免费   82篇
耳鼻咽喉   64篇
儿科学   450篇
妇产科学   290篇
基础医学   1070篇
口腔科学   211篇
临床医学   1037篇
内科学   2273篇
皮肤病学   217篇
神经病学   925篇
特种医学   686篇
外国民族医学   1篇
外科学   1210篇
综合类   295篇
一般理论   3篇
预防医学   670篇
眼科学   83篇
药学   454篇
  2篇
肿瘤学   529篇
  2021年   88篇
  2018年   114篇
  2017年   82篇
  2016年   94篇
  2015年   135篇
  2014年   168篇
  2013年   228篇
  2012年   300篇
  2011年   321篇
  2010年   242篇
  2009年   223篇
  2008年   326篇
  2007年   371篇
  2006年   307篇
  2005年   297篇
  2004年   295篇
  2003年   320篇
  2002年   297篇
  2001年   284篇
  2000年   313篇
  1999年   254篇
  1998年   238篇
  1997年   233篇
  1996年   222篇
  1995年   182篇
  1994年   193篇
  1993年   184篇
  1992年   245篇
  1991年   267篇
  1990年   244篇
  1989年   251篇
  1988年   275篇
  1987年   254篇
  1986年   257篇
  1985年   226篇
  1984年   202篇
  1983年   163篇
  1982年   119篇
  1981年   116篇
  1980年   101篇
  1979年   139篇
  1978年   90篇
  1977年   106篇
  1976年   104篇
  1975年   79篇
  1974年   96篇
  1973年   91篇
  1972年   87篇
  1971年   77篇
  1969年   73篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
Interleukin-6 (IL-6) was determined in serum and peritoneal dialysis effluent (PDE) of patients on chronic ambulatory peritoneal dialysis (CAPD) by a biological assay measuring the proliferation of the IL-6-dependent 7TD1 cell line. Six patients free of peritonitis displayed low but significant levels of IL-6 (mean +/- 42 pg/ml) in PDE, while IL-6 was undetectable in serum. In 6 patients with staphylococcal peritonitis, a tremendous increase in PDE levels of IL-6 was noted (range: 5,832-37,491 pg/ml), while serum IL-6 remained either undetectable or on a low level except in one case. After 5 days of antibiotic treatment, IL-6 levels in PDE returned to basal values. We conclude that CAPD results in an intraperitoneal secretion of IL-6 which is markedly but transiently increased during peritonitis episodes.  相似文献   
25.
26.
27.
28.
29.
Two experiments were conducted in which the acute effects of inhaled methanol on serum hormones associated with reproductive function in the male rat were evaluated. In the first experiment, rats exposed to methanol (0, 200, 5000 and 10,000 ppm) for 6 h were killed at the end of the exposure period (6 h) or the following morning (24 h). Also, because the process of exposure itself could modify neuroendocrine function, the effect of the handling associated with placing the rat in the exposure chamber was evaluated further by dividing the exposed animals into acclimated (2 weeks of prior handling) and non-acclimated groups. At 6 h, an effect of prior handling was noted in the sham-exposed rats, with serum luteinizing hormone (LH) of the non-acclimated group being greater than that of the acclimated group. Serum LH concentrations were altered by methanol exposure, but the direction of change and the exposure level at which an effect was noted differed between the acclimated and non-acclimated rats. Methanol (5000 ppm) reduced serum LH in the non-acclimated animals, while 10,000 ppm increased LH in the acclimated rats. Follicle stimulating hormone (FSH) and testosterone were unchanged by methanol in rats killed at 6 h. Thus, this experiment did not confirm earlier reports that exposure to 200 ppm for 6 h reduced serum testosterone. At 24 h, an effect of prior handling was still present in the hormonal measures, with serum and interstitial fluid testosterone concentrations being greater in the non-acclimated rats. Also, there was a dose x handling interaction with methanol exposure inducing an increase in serum testosterone in the non-acclimated rats (up to 5000 ppm) and a decrease in the acclimated rats (up to 10,000 ppm). In the second experiment, groups of acclimated and non-acclimated rats were exposed to 0 or 5000 ppm methanol for 1, 2 and 6 h and killed immediately after removal from the chamber. Serum LH, testosterone and FSH values were not different in sham- vs methanol-exposed rats at any time point. As in experiment 1, an effect of prior handling was noted. In general, the concentrations of these hormones and serum prolactin in the non-acclimated rats were greater than those observed for acclimated rats. Methanol exposure resulted in increased prolactin concentrations under both handling conditions.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
30.
The Fawn-Hooded strain of rats exhibits a hemorrhagic disorder, known as platelet storage pool deficiency. In addition to the platelet dysfunction, there is an altered response to certain serotonin drugs. To assess the characteristics of the binding to 5-HT1A and 5-HT2 receptors in this strain, regions of the brain from Fawn-Hooded, Sprague-Dawley and Wistar male rats were examined. The drug [3H]8-OH-DPAT was used to label 5-HT1A receptors and the Kd values for frontal cortex, hippocampus, striatum, hypothalamus and brainstem were similar in all three strains of rat. As with the 5-HT1A receptors, no differences were observed in the Kd values for 5-HT2 receptors, in any of the regions examined, among the three strains. However, the Bmax for the binding of [3H]8-OH-DPAT in the striatum and brainstem of Fawn-Hooded rats was less than in the Sprague-Dawley and Wistar animals. Furthermore, 5-HT2 receptors displayed a greater Bmax value in the striatum and in the frontal cortex of Fawn-Hooded animals, compared to Sprague-Dawley and Wistar rats. These differences in receptors are consistent with previous studies in which Fawn-Hooded rats were found to have altered serotonergic function, relative to Wistar and Sprague-Dawley animals.  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