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   75425篇
  免费   41265篇
  国内免费   11篇
耳鼻咽喉   1480篇
儿科学   4206篇
妇产科学   530篇
基础医学   15408篇
口腔科学   5054篇
临床医学   12184篇
内科学   22771篇
皮肤病学   7428篇
神经病学   13204篇
特种医学   2120篇
外科学   13533篇
综合类   9篇
一般理论   21篇
预防医学   4074篇
眼科学   1230篇
药学   5466篇
中国医学   1012篇
肿瘤学   6971篇
  2023年   34篇
  2022年   58篇
  2021年   1282篇
  2020年   5045篇
  2019年   10841篇
  2018年   10077篇
  2017年   11440篇
  2016年   12078篇
  2015年   11910篇
  2014年   11787篇
  2013年   12262篇
  2012年   4008篇
  2011年   3913篇
  2010年   8844篇
  2009年   5203篇
  2008年   1934篇
  2007年   767篇
  2006年   826篇
  2005年   593篇
  2004年   608篇
  2003年   615篇
  2002年   714篇
  2001年   759篇
  2000年   667篇
  1999年   247篇
  1998年   22篇
  1997年   20篇
  1996年   18篇
  1995年   10篇
  1994年   14篇
  1993年   7篇
  1992年   16篇
  1991年   8篇
  1990年   9篇
  1989年   8篇
  1987年   6篇
  1986年   4篇
  1982年   5篇
  1981年   2篇
  1980年   3篇
  1979年   2篇
  1978年   3篇
  1974年   2篇
  1972年   2篇
  1968年   3篇
  1967年   3篇
  1929年   1篇
  1924年   1篇
  1922年   2篇
  1913年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
The goal of endoscopic mucosal resection (EMR) is to allow the endoscopist to obtain tissue or resect lesions not previously amenable to standard biopsy or excisional techniques and to remove malignant lesions without open surgery. In this article, we describe the results of conventional EMR and EMR using an insulation‐tipped (IT) electrosurgical knife (submucosal dissection method) for large colorectal mucosal neoplasms and discuss the problems and future prospects of these procedures. At present, conventional EMR is much more feasible than EMR using IT‐knife from the perspectives of time, money, complication, and organ preservation. However, larger lesions tend to be resected in a piecemeal fashion; and it is difficult to confirm whether EMR has been complete. For accurate histopathological assessment of the resected specimen en bloc EMR is desirable although further experience is needed to establish its safety and efficacy. Further improvements of in EMR with special knife techniques are required to simply and safely remove large colorectal neoplasms.  相似文献   
93.
94.
95.
The objective of the study was to conduct a process and outcomes evaluation of the International AIDS Conference (IAC). Reaction evaluation data are presented from a delegate survey distributed at the 2004 IAC held in Thailand. Input and output data from the Thailand IAC are compared to data from previous IACs to ascertain attendance and reaction trends, which delegates benefit most, and host country effects. Outcomes effectiveness data were collected via a survey and intercept interviews. Data suggest that the host country may significantly affect the number and quality of basic science IAC presentations, who attends, and who benefits most. Intended and executed HIV work‐related behavior change was assessed under 9 classifications. Delegates who attended 1 previous IAC were more likely to report behavior changes than attendees who attended more than 1 previous IAC. The conference needs to be continually evaluated to elicit the required data to plan effective future IACs.  相似文献   
96.
This paper considers the immediate post‐traumatic reactions of rescue personnel who were exposed to the Hilton Hotel bombing in Sinai. The entire rescue personnel (n = 26) were assessed and separated into two groups on the basis of previous exposure to the same type of trauma. The results suggest that among rescue personnel, those with previous exposure had a lower level of post‐traumatic symptoms than those who were being exposed for the first time. This supports the hypothesis that previous exposure to the same type of trauma has an immunizing effect for subsequent same type of traumatic event among rescue personnel. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
97.
In this paper we describe Bonferroni‐based multiple testing procedures (MTPs) as strategies to split and recycle test mass. Here, ‘test mass’ refers to (parts of) the nominal level α at which the family‐wise error rate is controlled. Briefly, test mass is split between different null hypotheses, and whenever a null hypothesis is rejected, the part of α allocated to it may be recycled to the testing of other hypotheses. These recycling MTPs are closed testing procedures based on raw p‐values associated with testing the individual null hypotheses, and the class of such MTPs includes, for example, serial and parallel gatekeeping, fallback and Holm procedures. Graphical displays and a concise algebraic notation are provided for such MTPs. This recycling approach has pedagogical advantages and may facilitate the tailoring of MTPs for different purposes. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
98.
99.
Transection of an optic nerve (ON) is followed by slow removal of myelin. We studied microglia for the expression of molecules that characterize activated myelin phagocytosing macrophages: MAC-1, FcγII/III receptor (FcR), MAC-2, and F4/80. In-vitro, microglia expressed all molecules and phagocytosed myelin. In-vivo, intact ON displayed high levels of MAC-1, little FcR and F4/80, and no MAC-2. The expression of these molecules was upregulated differentially in in-vivo degenerating ON: MAC-1 uniformly, FcR and F4/80 variably, and MAC-2 sporadically. The distribution of MAC-2 expression correlated best with a pattern of sporadic structural degeneration. Thus in-vivo, ON injury is followed by deficient microglia activation, which we suggest contributes significantly to the slow clearance of myelin.  相似文献   
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