首页 | 官方网站   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   2040篇
  免费   121篇
  国内免费   18篇
医药卫生   2179篇
  2022年   14篇
  2021年   31篇
  2020年   21篇
  2019年   31篇
  2018年   39篇
  2017年   29篇
  2016年   39篇
  2015年   39篇
  2014年   63篇
  2013年   71篇
  2012年   109篇
  2011年   108篇
  2010年   67篇
  2009年   59篇
  2008年   62篇
  2007年   92篇
  2006年   85篇
  2005年   63篇
  2004年   53篇
  2003年   35篇
  2002年   40篇
  2001年   34篇
  2000年   40篇
  1999年   35篇
  1998年   55篇
  1997年   63篇
  1996年   60篇
  1995年   57篇
  1994年   54篇
  1993年   42篇
  1992年   32篇
  1991年   34篇
  1990年   47篇
  1989年   43篇
  1988年   52篇
  1987年   31篇
  1986年   38篇
  1985年   38篇
  1984年   28篇
  1983年   34篇
  1982年   25篇
  1981年   25篇
  1980年   13篇
  1979年   12篇
  1978年   12篇
  1977年   15篇
  1976年   18篇
  1975年   10篇
  1973年   12篇
  1967年   9篇
排序方式: 共有2179条查询结果,搜索用时 15 毫秒
31.
Human antibodies to human IgA globulins   总被引:4,自引:0,他引:4  
  相似文献   
32.
33.
34.

Background  

The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls.  相似文献   
35.
36.
37.
A species-specific receptor for polymerized human albumin (PHALB) has been reported on hepatitis B surface antigen (HBsAg)-carrying particles. Our previous observations that human Clq also binds PHALB in a species-restricted manner led us to investigate the possibility that HBsAg-associated Clq is involved in the PHALB receptor on HBsAg particles. The temperature, ionic strength, and pH requirements necessary for binding of PHALB to both Clq and HBsAg were compared and found to be similar. Normal human serum and purified Clq inhibited the PHABL-HBsAg interaction; the inhibition was markedly reduced in heat-inactivated and Clq-depleted serum. Heat-denatured or reduced and alky-lated Clq failed to inhibit the PHALB-HBsAg binding. Moreover, human Clq was found to be present in purified preparations of HBsAg and the quantity detected paralleled the degree of PHALB-HBsAg binding. While anti-Clq inhibited the PHALB-HBsAg interaction, anti-Clr, -Cls, -C3, and -Ig were not inhibitory. Collagenase treatment of purified HBsAg reduced both PHALB-binding activity and the degree of HBsAg-associated Clq. These observations provide evidence that HBsAg-associated Clq is involved in or near the HBsAg-binding site for PHALB.  相似文献   
38.
39.
The purpose of this study was to compare the serum Folic Acid (FA) levels in patients with Erectile Dysfunction (ED) and healthy controls and whether levels vary with its severity. The study was carried out on 77 sexually active individuals, out of which 41 complained of ED and 36 were apparently normal. Patients were excluded if they had any diseases known to cause ED. The severity was further categorised based on IIEF-5 scores. Blood serum levels of testosterone, lipid profile, random blood sugar, liver function test, renal function test and FA levels were obtained in each patient. Independent-samples t test of significance was used when comparing between two means. Pearson's correlation coefficient (r) test was used for correlating data. All clinical and biochemical parameters except FA were comparable in both the groups. FA levels were significantly decreased in ED group (5.29 vs. 10.8; p value = .004). Smoking habits were comparable between the groups, and FA levels did not vary among smokers and nonsmokers (p value = .46). Serum FA levels significantly declined with increasing severity of ED (8.28 vs. 5.56 vs. 4.37 vs. 3.5; p value < .001). Thus, decreased FA might possibly be one of the novel risk factors for ED.  相似文献   
40.
The effects of the H2-receptor antagonists, cimetidine and famotidine, on the microsomal metabolism of [14C]lovastatin were investigated. Liver microsomes were prepared from control, phenobarbital- and 3-methylcholanthrene-pretreated rats and humans (male and female). Concentration-dependent inhibition of the metabolism of lovastatin (0.1 mM) was observed with cimetidine (0.1 to 1.0 mM). In contrast, famotidine at a similar concentration was a very weak inhibitor. The formation of 6'beta-hydroxy-lovastatin, the major microsomal metabolite of lovastatin, was similarly inhibited. The results suggest that in vivo metabolic interaction with concomitantly administered lovastatin is less likely with famotidine than with cimetidine. Phenobarbital pretreatment produced 58% stimulation in overall metabolism, whereas 3-methylcholanthrene pretreatment had no effect relative to control rats (5.4 nmol/mg protein/min). Liver microsomes from phenobarbital-pretreated rats produced 67% more of the 6'beta-hydroxy-lovastatin but 63-66% less of the 3'-hydroxy and 6'-exomethylene metabolites. Liver microsomes from 3-methylcholanthrene-treated rats also produced less 3"-hydroxy-lovastatin (49%) but similar quantities of the other two metabolites. 6'beta-Hydroxy-lovastatin was a major metabolite with human liver microsomes. Interestingly with these microsomes, hydroxylation at the 3'-position of the molecule was a negligible pathway and hydrolysis to the hydroxy acid form was not observed. The formation of 6'-exomethylene-lovastatin was also catalyzed by human liver microsomes (0.5 to 0.8 nmol/mg protein/min).  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-23

京公网安备 11010802026262号