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   1528篇
  免费   73篇
  国内免费   1篇
耳鼻咽喉   11篇
儿科学   52篇
妇产科学   32篇
基础医学   150篇
口腔科学   11篇
临床医学   119篇
内科学   434篇
皮肤病学   16篇
神经病学   119篇
特种医学   47篇
外科学   140篇
综合类   23篇
预防医学   108篇
眼科学   82篇
药学   123篇
中国医学   13篇
肿瘤学   122篇
  2023年   7篇
  2022年   26篇
  2021年   58篇
  2020年   24篇
  2019年   29篇
  2018年   39篇
  2017年   27篇
  2016年   26篇
  2015年   35篇
  2014年   70篇
  2013年   74篇
  2012年   130篇
  2011年   109篇
  2010年   81篇
  2009年   46篇
  2008年   81篇
  2007年   78篇
  2006年   64篇
  2005年   61篇
  2004年   47篇
  2003年   31篇
  2002年   34篇
  2001年   27篇
  2000年   21篇
  1999年   32篇
  1998年   13篇
  1997年   11篇
  1996年   12篇
  1995年   8篇
  1993年   8篇
  1992年   30篇
  1991年   19篇
  1990年   16篇
  1989年   13篇
  1988年   10篇
  1987年   16篇
  1986年   21篇
  1985年   11篇
  1984年   13篇
  1983年   9篇
  1982年   6篇
  1979年   9篇
  1976年   6篇
  1975年   6篇
  1973年   10篇
  1972年   7篇
  1968年   9篇
  1967年   6篇
  1966年   7篇
  1965年   6篇
排序方式: 共有1602条查询结果,搜索用时 17 毫秒
51.
52.
53.
Liver cysts in the newborn often pose significant diagnostic challenges. Described herein is a case of large congenital liver cyst that was difficult to diagnose both antenatally and postnatally and which was later diagnosed as Caroli disease.  相似文献   
54.
The family histories of 976 South Indian Type 2 diabetic patients were recorded in a questionnaire-based survey to establish whether the excess maternal transmission of Type 2 diabetes reported in low prevalence Europid populations was also evident in this medium prevalence population. In 450 families (46.1 %), no parental history of diabetes was reported. In 423 families with one parent diabetic, 222 fathers (52.5 %) and 201 (47.5 %) mothers were diabetic. In the remaining 103 (10.6 %) families, both parents were diabetic. In contrast to previous studies, we found no evidence for substantial maternal excess in the transmission of diabetes (325 diabetic fathers vs 304 mothers; p = 0.4; p = 0.07 when compared using life table methods). The age of diagnosis of diabetes in probands was lower than that of their diabetic parents (p < 0.001): furthermore increasing parental history of diabetes was associated with an earlier diagnosis of diabetes in probands (p < 0.001). These results emphasize the extensive familial aggregation of Type 2 diabetes in this population but fail to replicate the evidence for excess maternal transmission evident in lower prevalence Europid populations, suggesting ethnic differences in the extent of this phenomenon.  相似文献   
55.
In 79 South Indian nuclear pedigrees ascertained via probands with NIDDM and both parents living, parental diabetic status was established through previously diagnosed NIDDM (n = 97) or oral glucose tolerance testing (n = 61). There was no significant difference between diabetes prevalence in mothers and fathers (60 vs 53 (76 % vs 67 %), respectively, p = 0.22). ‘Age at diabetes diagnosis’ survival curves did differ according to parental gender (p = 0.02) but this may reflect gender differences in health provision rather than pathophysiology. No maternal excess effects of the magnitude evident in previous studies were detected, suggesting either ethnic differences or overestimation of the maternal effect when reported histories of parental diabetes have been used. The tRNALeu(UUR) gene region was studied for diabetes-associated variation given the role of mutations in this gene in some pedigrees displaying maternal transmission of NIDDM. None of 142 unrelated South Indian NIDDM subjects displayed the MELAS mutation at nt3243. However, sequencing identified two variants of potential importance: (a) at nt3290 in the tRNALeu(UUR) gene, seen in 7/142 diabetic and 1/85 control subjects (p = 0.11), (b) at nt3316 in the ND1 gene (4/142 vs 1/85 subjects, respectively (p = 0.51)). Further studies are needed to determine the relevance of these variants to the development of NIDDM.  相似文献   
56.
Commercially pure (c.p.) titanium grade IV with a bimodal microstructure is a promising material for biomedical implants. The influence of the processing parameters on the physical, microstructural, and mechanical properties was investigated. The bimodal microstructure was achieved from the blends of powder particles with different sizes, while the porous structure was obtained using the space-holder technique (50 vol.% of ammonium bicarbonate). Mechanically milled powders (10 and 20 h) were mixed in 50 wt.% or 75 wt.% with c.p. titanium. Four different mixtures of powders were precompacted via uniaxial cold pressing at 400 MPa. Then, the specimens were sintered at 750 °C via hot pressing in an argon gas atmosphere. The presence of a bimodal microstructure, comprised of small-grain regions separated by coarse-grain ones, was confirmed by optical and scanning electron microscopies. The samples with a bimodal microstructure exhibited an increase in the porosity compared with the commercially available pure Ti. In addition, the hardness was increased while the Young’s modulus was decreased in the specimens with 75 wt.% of the milled powders (20 h).  相似文献   
57.
58.
59.
60.
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