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   48697篇
  免费   3087篇
  国内免费   155篇
耳鼻咽喉   652篇
儿科学   1412篇
妇产科学   856篇
基础医学   5764篇
口腔科学   796篇
临床医学   4936篇
内科学   10270篇
皮肤病学   858篇
神经病学   4546篇
特种医学   1989篇
外国民族医学   1篇
外科学   8645篇
综合类   466篇
一般理论   48篇
预防医学   3040篇
眼科学   797篇
药学   3014篇
中国医学   45篇
肿瘤学   3804篇
  2023年   212篇
  2022年   164篇
  2021年   857篇
  2020年   622篇
  2019年   1092篇
  2018年   1296篇
  2017年   951篇
  2016年   970篇
  2015年   1153篇
  2014年   1802篇
  2013年   2299篇
  2012年   3731篇
  2011年   3887篇
  2010年   2170篇
  2009年   1855篇
  2008年   3401篇
  2007年   3574篇
  2006年   3550篇
  2005年   3455篇
  2004年   3329篇
  2003年   3093篇
  2002年   2837篇
  2001年   365篇
  2000年   255篇
  1999年   366篇
  1998年   490篇
  1997年   375篇
  1996年   278篇
  1995年   331篇
  1994年   318篇
  1993年   260篇
  1992年   205篇
  1991年   195篇
  1990年   173篇
  1989年   160篇
  1988年   161篇
  1987年   141篇
  1986年   136篇
  1985年   141篇
  1984年   178篇
  1983年   177篇
  1982年   201篇
  1981年   173篇
  1980年   122篇
  1979年   82篇
  1978年   77篇
  1977年   65篇
  1976年   42篇
  1975年   29篇
  1974年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Clinical Rheumatology - This study aimed to assess treatment patterns and frequency of inadequate response associated with advanced therapy initiation among patients with ankylosing spondylitis...  相似文献   
2.
Journal of Neuro-Oncology - These recommendations apply to adults with glioblastoma who have been previously treated with first-line radiation or chemoradiotherapy and who are suspected of...  相似文献   
3.
Pharmaceutical Research - The quality testing and approval procedure for most pharmaceutical products is a streamlined process with standardized procedures for the determination of critical quality...  相似文献   
4.
5.
Cognitive Therapy and Research - Baseline severity has emerged as a key predictor of acute response to treatments for depression. The goals of this individual patient data meta-analysis were to...  相似文献   
6.
Journal of Neuro-Oncology - Leptomeningeal metastases (LM) constitute an involvement of cancer which is associated with marked morbidity and mortality. The contemporary diagnostic and therapeutic...  相似文献   
7.
Background: Variation in facial shape may arise from the combinatorial or overlapping actions of paralogous genes. Given its many members, and overlapping expression and functions, the EPH receptor family is a compelling candidate source of craniofacial morphological variation. We performed a detailed morphometric analysis of an allelic series of E14.5 Ephb1-3 receptor mutants to determine the effect of each paralogous receptor gene on craniofacial morphology. Results: We found that Ephb1, Ephb2, and Ephb3 genotypes significantly influenced facial shape, but Ephb1 effects were weaker than Ephb2 and Ephb3 effects. Ephb2−/− and Ephb3−/− mutations affected similar aspects of facial morphology, but Ephb3−/− mutants had additional facial shape effects. Craniofacial differences across the allelic series were largely consistent with predicted additive genetic effects. However, we identified a potentially important nonadditive effect where Ephb1 mutants displayed different morphologies depending on the combination of other Ephb paralogs present, where Ephb1+/−, Ephb1−/−, and Ephb1−/−; Ephb3−/− mutants exhibited a consistent deviation from their predicted facial shapes. Conclusions: This study provides a detailed assessment of the effects of Ephb receptor gene paralogs on E14.5 mouse facial morphology and demonstrates how the loss of specific receptors contributes to facial dysmorphology.  相似文献   
8.
9.
10.
Lignin and lignin-based materials have received considerable attention in various fields due to their promise as sustainable feedstocks. Guaiacol (G) and syringol (S) are two primary monolignols that occur in different ratios for different plant species. As methoxyphenols, G and S have been targeted as atmospheric pollutants and their acute toxicity examined. However, there is a rare understanding of the toxicological properties on other endpoints and mixture effects of these monolignols. To fill this knowledge gap, our study investigated the impact of different S/G ratios (0.5, 1, and 2) and three lignin depolymerization samples from poplar, pine, and miscanthus species on mutagenicity and developmental toxicity. A multitiered method consisted of in silico simulation, in vitro Ames test, and in vivo chicken embryonic assay was employed. In the Ames test, syringol showed a sign of mutagenicity, whereas guaiacol did not, which agreed with the T.E.S.T. simulation. For three S and G mixture and lignin monomers, mutagenic activity was related to the proportion of syringol. In addition, both S and G showed developmental toxicity in the chicken embryonic assay and T.E.S.T. simulation, and guaiacol had a severe effect on lipid peroxidation. A similar trend and comparable developmental toxicity levels were detected for S and G mixtures and the three lignin depolymerized monomers. This study provides data and insights on the differential toxicity of varying S/G ratios for some important building blocks for bio-based materials.  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