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   3227032篇
  免费   250478篇
  国内免费   7559篇
耳鼻咽喉   45469篇
儿科学   101504篇
妇产科学   86698篇
基础医学   460681篇
口腔科学   92513篇
临床医学   303071篇
内科学   621199篇
皮肤病学   64951篇
神经病学   271020篇
特种医学   125159篇
外国民族医学   1128篇
外科学   471957篇
综合类   76387篇
现状与发展   2篇
一般理论   1361篇
预防医学   269500篇
眼科学   74989篇
药学   240864篇
  10篇
中国医学   6506篇
肿瘤学   170100篇
  2018年   34774篇
  2017年   26573篇
  2016年   29077篇
  2015年   33097篇
  2014年   47025篇
  2013年   72378篇
  2012年   98237篇
  2011年   103937篇
  2010年   60976篇
  2009年   57629篇
  2008年   97442篇
  2007年   103593篇
  2006年   104434篇
  2005年   101422篇
  2004年   97142篇
  2003年   93427篇
  2002年   91599篇
  2001年   144605篇
  2000年   149462篇
  1999年   126438篇
  1998年   37233篇
  1997年   33786篇
  1996年   33218篇
  1995年   32103篇
  1994年   30138篇
  1993年   28216篇
  1992年   102226篇
  1991年   99312篇
  1990年   96203篇
  1989年   92264篇
  1988年   85732篇
  1987年   84300篇
  1986年   80193篇
  1985年   76639篇
  1984年   58252篇
  1983年   49716篇
  1982年   30262篇
  1981年   26935篇
  1979年   54336篇
  1978年   38435篇
  1977年   32133篇
  1976年   30614篇
  1975年   32087篇
  1974年   39427篇
  1973年   37954篇
  1972年   35356篇
  1971年   32801篇
  1970年   30682篇
  1969年   28388篇
  1968年   26268篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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   
92.
93.
94.
95.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  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