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   35976篇
  免费   2046篇
  国内免费   126篇
耳鼻咽喉   445篇
儿科学   2132篇
妇产科学   711篇
基础医学   4600篇
口腔科学   814篇
临床医学   2497篇
内科学   7321篇
皮肤病学   843篇
神经病学   1928篇
特种医学   792篇
外科学   5031篇
综合类   1336篇
一般理论   15篇
预防医学   2121篇
眼科学   1461篇
药学   3545篇
中国医学   275篇
肿瘤学   2281篇
  2023年   215篇
  2022年   360篇
  2021年   1169篇
  2020年   642篇
  2019年   864篇
  2018年   1067篇
  2017年   733篇
  2016年   969篇
  2015年   1010篇
  2014年   1381篇
  2013年   1838篇
  2012年   2472篇
  2011年   2462篇
  2010年   1397篇
  2009年   1266篇
  2008年   1834篇
  2007年   1760篇
  2006年   1776篇
  2005年   1396篇
  2004年   1405篇
  2003年   1193篇
  2002年   1016篇
  2001年   823篇
  2000年   873篇
  1999年   732篇
  1998年   311篇
  1997年   216篇
  1996年   223篇
  1995年   218篇
  1994年   176篇
  1993年   151篇
  1992年   499篇
  1991年   405篇
  1990年   433篇
  1989年   395篇
  1988年   357篇
  1987年   357篇
  1986年   348篇
  1985年   323篇
  1984年   262篇
  1983年   219篇
  1979年   228篇
  1978年   148篇
  1977年   179篇
  1976年   140篇
  1975年   171篇
  1974年   182篇
  1973年   182篇
  1972年   173篇
  1971年   161篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
Amino acid residues in the N-terminal of the PA subunit (PAN) of the influenza A virus polymerase play critical roles in endonuclease activity, protein stability, and viral RNA (vRNA) promoter binding. In addition, PAN is highly conserved among different subtypes of influenza virus, which suggests PAN to be a desired target in the development of anti-influenza agents. We selected DNA aptamers targeting the intact PA protein or the PAN domain of an H5N1 virus strain using systematic evolution of ligands by exponential enrichment (SELEX). The binding affinities of selected aptamers were measured, followed by an evaluation of in vitro endonuclease inhibitory activity. Next, the antiviral effects of enriched aptamers against influenza A virus infections were examined. A total of three aptamers targeting PA and six aptamers targeting PAN were selected. Our data demonstrated that all three PA-selected aptamers neither inhibited endonuclease activity nor exhibited antiviral efficacy, whereas four of the six PAN-selected aptamers inhibited both endonuclease activity and H5N1 virus infection. Among the four effective aptamers, one exhibited cross-protection against infections of H1N1, H5N1, H7N7, and H7N9 influenza viruses, with a 50% inhibitory concentration (IC50) of around 10 nM. Notably, this aptamer was identified at the 5th round but disappeared after the 10th round of selection, suggesting that the identification and evaluation of aptamers at early rounds of selection may be highly helpful for screening effective aptamers. Overall, our study provides novel insights for screening and developing effective aptamers for use as anti-influenza drugs.  相似文献   
992.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - In vitro antioxidant potential of methanolic extract of saffron and crocetin was assessed along with...  相似文献   
993.
One of the most common tumors of the eye diagnosed in childhood is retinoblastoma, which mandates enucleation with adjunctive chemotherapy and radiotherapy to save the patient's life. The most common late enucleation complication is post‐enucleation socket syndrome (PESS), which poses a management dilemma for the prosthodontist and surgeon, along with being a major esthetic concern for the patient. The reconstruction of such sockets is complex. The purpose of this clinical report is to describe the rehabilitation of such a pediatric patient with severe PESS. The patient was successfully rehabilitated by presurgical conformer therapy, socket reconstruction surgery with non‐meshed intermediate split thickness skin graft (STSG)/Blair‐Brown graft, and postsurgical conformer stent. This was followed by fabrication of a custom ocular prosthesis, to achieve favorable functional, physical, and psychological effects.  相似文献   
994.
Poly(ethylene glycol) (PEG)‐based hydrogels are extensively used in a variety of biomedical applications, due to ease of synthesis and tissue‐like properties. Recently there have been varied reports regarding PEG hydrogel's degradation kinetics and in vivo host response. In particular, these studies suggest that the surrounding tissue environment could play a critical role in defining the inflammatory response and degradation kinetics of PEG implants. In the present study we demonstrated a potential mechanism of PEG hydrogel degradation, and in addition we show potential evidence of the role of the surrounding tissue environment on producing variable inflammatory responses. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
995.
996.
Upper limb length discrepancy is a rare occurrence. Humerus shortening may need specialized treatment to restore the functional and cosmetic status of upper limb. We report a case of humerus lengthening of 9 cm with a monorail external fixator and the result was observed during a 2-year follow-up. Humerus lengthening needs specialized focus as it is not only a cosmetic issue but also a functional demand. The monorail unilateral fixator is more functional and cosmetically acceptable, and thus becomes an effective treatment option.  相似文献   
997.
Singh  Simron  Dey  Chris  Kennecke  Hagen  Kocha  Walter  Maroun  Jean  Metrakos  Peter  Mukhtar  Tariq  Pasieka  Janice  Rayson  Daniel  Rowsell  Corwyn  Sideris  Lucas  Wong  Ralph  Law  Calvin 《Annals of surgical oncology》2015,22(8):2685-2699
Annals of Surgical Oncology - Pancreatic neuroendocrine tumors (pNETs) are rare heterogeneous tumors that have been steadily increasing in both incidence and prevalence during the past few decades....  相似文献   
998.
999.
1000.
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