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   6979篇
  免费   530篇
  国内免费   21篇
耳鼻咽喉   44篇
儿科学   228篇
妇产科学   234篇
基础医学   1063篇
口腔科学   135篇
临床医学   972篇
内科学   1328篇
皮肤病学   144篇
神经病学   595篇
特种医学   148篇
外科学   537篇
综合类   69篇
一般理论   22篇
预防医学   808篇
眼科学   164篇
药学   464篇
中国医学   5篇
肿瘤学   570篇
  2023年   73篇
  2022年   97篇
  2021年   162篇
  2020年   161篇
  2019年   186篇
  2018年   190篇
  2017年   174篇
  2016年   154篇
  2015年   192篇
  2014年   300篇
  2013年   397篇
  2012年   534篇
  2011年   539篇
  2010年   282篇
  2009年   274篇
  2008年   470篇
  2007年   469篇
  2006年   437篇
  2005年   425篇
  2004年   402篇
  2003年   339篇
  2002年   320篇
  2001年   60篇
  2000年   45篇
  1999年   48篇
  1998年   64篇
  1997年   61篇
  1996年   38篇
  1995年   34篇
  1994年   45篇
  1993年   33篇
  1992年   38篇
  1991年   28篇
  1990年   24篇
  1989年   28篇
  1988年   28篇
  1987年   19篇
  1986年   19篇
  1985年   18篇
  1984年   23篇
  1983年   26篇
  1982年   34篇
  1981年   23篇
  1980年   29篇
  1979年   28篇
  1978年   19篇
  1977年   17篇
  1975年   13篇
  1974年   13篇
  1973年   15篇
排序方式: 共有7530条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.

Background

We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.

Methods

In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).

Results

After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).

Conclusions

This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy.  相似文献   
6.
7.
Human histocompatibility leukocyte antigen E (HLA-E) and mouse major histocompatibility complex (MHC) class Ib antigen, Qa-1, share the same substitutions at two normally conserved positions 143 and 147, which are likely to affect binding of the C terminus of peptides. Qa-1 is able to bind a peptide derived from the leader sequence of H-2 D and H-2 L molecules. We developed a peptide binding assay in vitro to compare the binding specificity of HLA-E with the mouse MHC class Ib molecule Qa-1. We demonstrate that HLA-E binds, although poorly, the peptide which binds to Qa-1 and that it also binds nonamer signal sequence-derived peptides from human MHC class I molecules. Using alanine and glycine substitutions, we could define primary anchor residues at positions 2 and 9 and secondary anchor residues at position 7 and possibly 3.  相似文献   
8.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  相似文献   
9.
10.
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