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   822篇
  免费   26篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   46篇
妇产科学   15篇
基础医学   61篇
口腔科学   7篇
临床医学   60篇
内科学   125篇
皮肤病学   9篇
神经病学   63篇
特种医学   127篇
外科学   155篇
综合类   44篇
一般理论   1篇
预防医学   20篇
眼科学   8篇
药学   36篇
肿瘤学   76篇
  2024年   2篇
  2021年   20篇
  2020年   9篇
  2019年   14篇
  2018年   23篇
  2017年   13篇
  2016年   8篇
  2015年   13篇
  2014年   18篇
  2013年   42篇
  2012年   35篇
  2011年   47篇
  2010年   37篇
  2009年   34篇
  2008年   30篇
  2007年   33篇
  2006年   38篇
  2005年   24篇
  2004年   48篇
  2003年   26篇
  2002年   19篇
  2001年   14篇
  2000年   9篇
  1999年   9篇
  1998年   26篇
  1997年   28篇
  1996年   23篇
  1995年   30篇
  1994年   16篇
  1993年   9篇
  1992年   7篇
  1991年   7篇
  1990年   9篇
  1989年   17篇
  1988年   15篇
  1987年   13篇
  1986年   12篇
  1985年   4篇
  1984年   6篇
  1983年   9篇
  1982年   7篇
  1981年   11篇
  1980年   9篇
  1979年   7篇
  1978年   7篇
  1977年   4篇
  1970年   2篇
  1968年   2篇
  1926年   1篇
  1925年   1篇
排序方式: 共有855条查询结果,搜索用时 15 毫秒
21.
22.
Indian Journal of Thoracic and Cardiovascular Surgery -  相似文献   
23.
Live attenuated influenza vaccine (LAIV) has had a tumultuous recent history that can be difficult for many to follow and understand. Prior to 2013, LAIV had a record of accomplishment of providing equal or superior protection against influenza in children. Since 2013, concerns about the lack of protection with LAIV against pandemic H1N1 strains led to the withdrawal of any recommendation for use in the US by the Advisory Committee on Immunization Practices (ACIP). After some significant changes to the content, evaluation and production of LAIV, it has been be recommended again for use in the US in 2018-19. This commentary reviews the origin of LAIV, the events and circumstances that led to the withdrawal of any recommendation for LAIV use by the ACIP, the merits, shortcomings and repercussions of that decision and finally offers some thoughts about the future of LAIV.  相似文献   
24.
25.
Cav2.2 high voltage-gated calcium channels are regulated by phorbol-12-myristae, 13-acetate (PMA) via Ser/Thr protein kinase C (PKC) phosphorylation sites in the I–II linker and C-terminus of the α1 2.2 subunit. Here we show that PMA enhancement of Cav2.2 currents expressed in Xenopus oocytes can be blocked by inhibitors of PKC βII or PKC ε isozymes, as shown previously for Cav2.3 currents, and that microinjection of PKC βII or PKC ε isozymes in the oocytes expressing the WT Cav2.2 channels increases the basal barium current (IBa). The I–V plot shows a large increase in current amplitude with PKC βII and PKC ε isozymes with only a small shift in the peak IBa in the hyperpolarizing direction. The potentiation of Cav2.2 currents by microinjection of PKC βII and PKC ε isozymes was not altered by the inhibition of G proteins with GDPβS. The combination of isozyme specific inhibitors with previously generated Ser/Thr to Ala mutants of α1 2.2 subunit revealed that PKC βII or PKC ε isozymes (but not PKC α or δ) can provide full enhancement through the stimulatory site (Thr-422) in the I–II linker but that PKC ε is better at decreasing channel activity through the inhibitory site Ser-425. The enhancing effect of PKC βII or ε at Thr-422 is dominant over the inhibitory effect at Ser-425. Injected PKC βII also enhances Cav2.2 current when any of the potential stimulatory sites (Ser-1757, Ser-2108 and Ser-2132) are available in the C-terminus. PKC ε provides lesser enhancement with C-terminal sites and only with Ser-2108 and Ser-2132. Sites Ser-1757 and Ser-2132, but not Ser-2108, are dominant over the inhibitory site Ser-425. Collectively, these results reveal a hierarchy of regulatory sites in Cav2.2 channels. Site-specific regulation by different PKC isozymes may allow graded levels of channel activation and susceptibility or resistance to subsequent stimulatory events.  相似文献   
26.
L-ficolin, like mannan-binding lectin (MBL), is a lectin pathway activator present in normal human plasma. Upon binding ligand, l-ficolin similarly initiates C4 cleavage via the serine protease MBL-associated serine protease-2 (MASP-2). We sought further insight into l-ficolin binding reactions and MASP-2 activation by passing plasma through GlcNAc-derivatized Sepharose. l-Ficolin bound in 1.0 M NaCl-ethylenediamine tetraacetic acid (EDTA), and remained bound in NaCl-free EDTA, while MASP-2 eluted in proenzyme form ( approximately 20% yield, > 40 000-fold purification). L-Ficolin was eluted with GlcNAc in 1.0 M NaCl ( approximately 10% yield, > 3000-fold purification), with trace amounts of C3, alpha(2)-macroglobulin and both native and activated MASP-2. These preparations were utilized to investigate l-ficolin reactivities with acetylated low-density lipoprotein (A-LDL) as a model ligand in albumin-free systems. L-Ficolin bound strongly to A-LDL in the absence as well as presence of calcium, including saline-EDTA, and was optimal in 1.0 M NaCl-EDTA, but binding failed to occur in EDTA in the absence of NaCl. The addition of l-ficolin to immobilized A-LDL resulted in activation of MASP-2 in unmodified but not ficolin-depleted plasma unless l-ficolin was restored. We conclude that A-LDL is a useful ligand for investigation of l-ficolin function; both binding and activation are optimally examined in systems free of albumin; and ligand binding in 1.0 M NaCl in EDTA can be useful in the isolation of l-ficolin and native MASP-2.  相似文献   
27.
28.
Guillain-Barr啨综合征(GBS)和Miller Fisher综合征(MFS)的诊断标准随着临床研究的深入在不断演变。2011年1月,《疫苗》杂志发表了国际疫苗安全性监测Brighton合作组关于GBS/MFS的诊断定义和研究资料收集规范。此文献中未采用"诊断标准"而采用"诊断定义"是因为其主要目的为评价疫苗安全性而制定,而非用于神经科的GBS/  相似文献   
29.
30.
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