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   925554篇
  免费   74844篇
  国内免费   2012篇
耳鼻咽喉   13274篇
儿科学   26562篇
妇产科学   26181篇
基础医学   132729篇
口腔科学   26799篇
临床医学   82006篇
内科学   178003篇
皮肤病学   17867篇
神经病学   76164篇
特种医学   37187篇
外国民族医学   172篇
外科学   144882篇
综合类   25379篇
现状与发展   2篇
一般理论   328篇
预防医学   72664篇
眼科学   22124篇
药学   68997篇
  1篇
中国医学   1662篇
肿瘤学   49427篇
  2018年   8824篇
  2016年   7758篇
  2015年   9103篇
  2014年   13181篇
  2013年   19641篇
  2012年   27332篇
  2011年   28530篇
  2010年   16523篇
  2009年   15450篇
  2008年   26853篇
  2007年   29307篇
  2006年   29112篇
  2005年   28534篇
  2004年   27921篇
  2003年   26665篇
  2002年   25603篇
  2001年   36333篇
  2000年   36834篇
  1999年   31475篇
  1998年   10001篇
  1997年   9205篇
  1996年   9035篇
  1995年   8551篇
  1994年   8149篇
  1992年   26969篇
  1991年   26379篇
  1990年   25838篇
  1989年   24911篇
  1988年   23466篇
  1987年   23056篇
  1986年   21948篇
  1985年   21310篇
  1984年   16672篇
  1983年   14293篇
  1982年   9188篇
  1981年   8525篇
  1980年   7984篇
  1979年   16917篇
  1978年   12319篇
  1977年   10348篇
  1976年   9445篇
  1975年   10237篇
  1974年   12729篇
  1973年   12213篇
  1972年   11606篇
  1971年   10742篇
  1970年   10274篇
  1969年   9945篇
  1968年   8924篇
  1967年   8247篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
The purpose of this study was to evaluate the use of serum fibronectin and serum somatomedin-C as nutritional markers during enteral nutrition support (ENS) of critically ill, traumatized patients using an enteral product containing high concentrations of branched-chain amino acids. Twelve critically injured patients received a standard enteral formula with 30 g of a 44% branched-chain amino acid supplement added to each liter of formula. Fibronectin concentration, somatomedin-C concentration, and nitrogen balance were measured on study days 1, 4, 7, 14, 21, 28 or until adequate oral intake began. Both fibronectin and somatomedin-C concentrations increased significantly from baseline by day 7 of ENS. Nitrogen balance increased significantly from baseline by day 4. On days 14 and 21, only somatomedin-C and nitrogen balance increased significantly from baseline. Nitrogen balance was significantly correlated with somatomedin-C concentration (r = 0.53, p less than 0.01), cumulative caloric intake (r = 0.68, p less than 0.01), and cumulative nitrogen intake (r = 0.72, p less than 0.01). The results of this study suggest that serum somatomedin-C is useful and serum fibronectin has potential in monitoring nutrition support response in critically ill, traumatized patients.  相似文献   
993.
Amino acid concentrations were measured in the cord blood serum from neonates following 23-41 weeks gestation. These values were then correlated with the gestational age of the newborns. A significant (p less than 0.05) correlation was observed with the concentrations of six amino acids, and five of these correlations were negative. The significance of these normative data are discussed and compared with currently available cord blood aminogram data.  相似文献   
994.
Elevation of prostaglandins and protein in the aqueous humor is an immediate response to Yag-laser anterior capsulotomy. There was a significant correlation between prostaglandins and thromboxane to the elevation of intraocular pressure. The elevation of protein concentration was proportional to the elevation of prostaglandin F1, but not to thromboxane. The biochemical changes in the aqueous humor were more severe as laser power was increased above 3 mj. While the role of prostaglandins in the elevation of intraocular pressure is uncertain, the present data recommend the selection of laser power below 3 mj to avoid pressure rise instead of inhibition of all prostaglandin synthesis by medication.  相似文献   
995.
Using a two-dimensional scanning fluorophotometer, we studied 50 subjects with symmetric ocular involvement of Fuchs' dystrophy without epithelial edema. Twenty-six subjects with confluent or nearly confluent cornea gutata with increased corneal thickness and 24 subjects with mild to moderate cornea guttata with normal corneal thickness were compared to normal control subjects. There were no statistically significant differences in endothelial permeability between the three groups. Corneal thickness was significantly increased in the subjects with confluent to nearly confluent guttae, however. These results suggest that endothelial pump function may be affected in subjects with advanced cornea guttata with stromal edema.  相似文献   
996.
We present three cases of Lyme disease, complicated by ocular manifestations. These included optic nerve abnormalities and corneal opacities.  相似文献   
997.
998.
999.
1000.
Research investigating predictors of risky sexual behavior of rural MSM is sparse, even though the prevalence of HIV in rural areas has increased. This study explored two sets of predictors of 93 rural MSM's levels of risky sexual behavior: mental health variables and stigma emanating from men's family members, health care professionals, and people in the rural communities in which they live. Over 47% of the men were found to be at modified high to high risk. Logistic regression using a continuation logit model was used to test the relationship of the predictor variables and the four levels of risk. Findings indicate that self-esteem was predictive of the highest sexual risk behavior but not lower levels of risk. Stigma was predictive of modified high sexual risk when compared to low and no risk categories. No variables differentiated men at low risk from men at no risk.  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