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   5575篇
  免费   471篇
  国内免费   63篇
耳鼻咽喉   44篇
儿科学   265篇
妇产科学   114篇
基础医学   615篇
口腔科学   113篇
临床医学   711篇
内科学   1141篇
皮肤病学   79篇
神经病学   452篇
特种医学   289篇
外科学   744篇
综合类   160篇
一般理论   26篇
预防医学   600篇
眼科学   39篇
药学   340篇
中国医学   11篇
肿瘤学   366篇
  2023年   77篇
  2022年   102篇
  2021年   302篇
  2020年   145篇
  2019年   244篇
  2018年   266篇
  2017年   190篇
  2016年   169篇
  2015年   163篇
  2014年   246篇
  2013年   329篇
  2012年   364篇
  2011年   422篇
  2010年   236篇
  2009年   217篇
  2008年   271篇
  2007年   277篇
  2006年   229篇
  2005年   223篇
  2004年   194篇
  2003年   142篇
  2002年   128篇
  2001年   66篇
  2000年   44篇
  1999年   40篇
  1998年   104篇
  1997年   81篇
  1996年   77篇
  1995年   67篇
  1994年   58篇
  1993年   59篇
  1992年   38篇
  1991年   32篇
  1990年   51篇
  1989年   41篇
  1988年   45篇
  1987年   41篇
  1986年   42篇
  1985年   29篇
  1984年   21篇
  1983年   20篇
  1982年   23篇
  1981年   15篇
  1980年   17篇
  1979年   23篇
  1978年   15篇
  1977年   13篇
  1976年   24篇
  1975年   15篇
  1970年   10篇
排序方式: 共有6109条查询结果,搜索用时 15 毫秒
1.
2.
Nidogen 1 (NID1) is a glycoprotein found in basement membranes involved in cross-linking collagen IV and laminin. The role of NID in breast cancer has only been evaluated in a small number of studies and the findings of these studies have been inconsistent. Our previous work revealed that highly tumorigenic murine mammary tumor cells express high levels of Nid1 while weakly tumorigenic mammary tumor cells express low levels of Nid1. To investigate Nid1, two stable knockdown lines were created, and Nid1 knockdown was confirmed at both the mRNA and protein level. Nid1 knockdown significantly reduced cell proliferation and migration/invasion and these reductions in proliferation and migration/invasion could be rescued by conditioned media containing NID1 protein. The reduced migration/invasion observed in the Nid1 knockdown cells was not associated with significant alterations in the epithelial gene Cdh1 or the mesenchymal genes Snai1, Snai2, Twist1, Twist2, Zeb1 and Zeb2. Therefore, suppression of Nid1 expression reduces proliferation and migration/invasion in claudin-low murine mammary tumor cells.  相似文献   
3.
4.
Progress in the understanding of the biology and therapy of acute myeloid leukemia (AML) is occurring rapidly. Since 2017, nine agents have been approved for various indications in AML. These included several targeted therapies like venetoclax, FLT3 inhibitors, IDH inhibitors, and others. The management of AML is complicated, highlighting the need for expertise in order to deliver optimal therapy and achieve optimal outcomes. The multiple subentities in AML require very different therapies. In this review, we summarize the important pathophysiologies driving AML, review current therapies in standard practice, and address present and future research directions.Subject terms: Prognosis, Health services  相似文献   
5.
Haaga  JR; Beale  SM 《Radiology》1986,161(3):829-830
By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6).  相似文献   
6.
7.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  相似文献   
8.
9.
外科医生和手术室人员经常接触手术设备产生的烟气,病人也会暴露于烟气中,特别是腹腔镜手术中产生的烟气滞留于腹腔内这一密闭空间并被吸收.这些烟气是一种与香烟烟气相似的毒性物质,然而对这种毒性物质的影响还未引起足够重视.应该采取必要措施尽可能减少手术中烟气的不良影响.  相似文献   
10.
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