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   2271427篇
  免费   174448篇
  国内免费   4088篇
耳鼻咽喉   31749篇
儿科学   74971篇
妇产科学   64731篇
基础医学   322043篇
口腔科学   65706篇
临床医学   197596篇
内科学   445729篇
皮肤病学   48533篇
神经病学   183289篇
特种医学   90960篇
外国民族医学   767篇
外科学   348464篇
综合类   54461篇
现状与发展   3篇
一般理论   768篇
预防医学   173199篇
眼科学   52600篇
药学   168834篇
  3篇
中国医学   4290篇
肿瘤学   121267篇
  2018年   21554篇
  2016年   18692篇
  2015年   21536篇
  2014年   30015篇
  2013年   46152篇
  2012年   62185篇
  2011年   65721篇
  2010年   39084篇
  2009年   37429篇
  2008年   62937篇
  2007年   66579篇
  2006年   67464篇
  2005年   65693篇
  2004年   64337篇
  2003年   61666篇
  2002年   60559篇
  2001年   104147篇
  2000年   107717篇
  1999年   91542篇
  1998年   25224篇
  1997年   23051篇
  1996年   22868篇
  1995年   22041篇
  1994年   20759篇
  1993年   19677篇
  1992年   74851篇
  1991年   72465篇
  1990年   70845篇
  1989年   68627篇
  1988年   63757篇
  1987年   62876篇
  1986年   60069篇
  1985年   57728篇
  1984年   43346篇
  1983年   37115篇
  1982年   22000篇
  1981年   19517篇
  1980年   18446篇
  1979年   40881篇
  1978年   28531篇
  1977年   24008篇
  1976年   22667篇
  1975年   24309篇
  1974年   29547篇
  1973年   28410篇
  1972年   26278篇
  1971年   24612篇
  1970年   22957篇
  1969年   21522篇
  1968年   20004篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Canadian Journal of Anesthesia/Journal canadien d'anesthésie -  相似文献   
94.
Tarentola annularis is a climbing gecko with a wide distribution in Africa north of the equator. In the present paper, we describe the development of the osteocranium of this lizard, from the first appearance of the cranial elements up to the point of hatching. This is based on a combination of histology and cleared and stained specimens. This is the first comprehensive account of gekkotan pre-hatching skull development based on a comprehensive series of embryos, rather than a few selected stages. Given that Gekkota is now widely regarded as representing the sister group to other squamates, this account helps to fill a significant gap in the literature. Moreover, as many authors have considered features of the gekkotan skull and skeleton to be indicative of paedomorphosis, it is important to know whether this hypothesis is supported by delays in the onset of cranial ossification. In fact, we found the sequence of cranial bone ossification to be broadly comparable to that of other squamates studied to date, with no significant lags in development.  相似文献   
95.
BACKGROUND. The identification and treatment of individuals with tuberculosis (TB) is a global public health priority. Accurate diagnosis of pulmonary active TB (ATB) disease remains challenging and relies on extensive medical evaluation and detection of Mycobacterium tuberculosis (Mtb) in the patient’s sputum. Further, the response to treatment is monitored by sputum culture conversion, which takes several weeks for results. Here, we sought to identify blood-based host biomarkers associated with ATB and hypothesized that immune activation markers on Mtb-specific CD4+ T cells would be associated with Mtb load in vivo and could thus provide a gauge of Mtb infection.METHODS. Using polychromatic flow cytometry, we evaluated the expression of immune activation markers on Mtb-specific CD4+ T cells from individuals with asymptomatic latent Mtb infection (LTBI) and ATB as well as from ATB patients undergoing anti-TB treatment.RESULTS. Frequencies of Mtb-specific IFN-γ+CD4+ T cells that expressed immune activation markers CD38 and HLA-DR as well as intracellular proliferation marker Ki-67 were substantially higher in subjects with ATB compared with those with LTBI. These markers accurately classified ATB and LTBI status, with cutoff values of 18%, 60%, and 5% for CD38+IFN-γ+, HLA-DR+IFN-γ+, and Ki-67+IFN-γ+, respectively, with 100% specificity and greater than 96% sensitivity. These markers also distinguished individuals with untreated ATB from those who had successfully completed anti-TB treatment and correlated with decreasing mycobacterial loads during treatment.CONCLUSION. We have identified host blood-based biomarkers on Mtb-specific CD4+ T cells that discriminate between ATB and LTBI and provide a set of tools for monitoring treatment response and cure.TRIAL REGISTRATION. Registration is not required for observational studies.FUNDING. This study was funded by Emory University, the NIH, and the Yerkes National Primate Center.  相似文献   
96.
97.
98.
99.
100.
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