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   14012篇
  免费   1402篇
  国内免费   1313篇
耳鼻咽喉   31篇
儿科学   225篇
妇产科学   92篇
基础医学   830篇
口腔科学   204篇
临床医学   701篇
内科学   1199篇
皮肤病学   313篇
神经病学   274篇
特种医学   776篇
外科学   609篇
综合类   1903篇
一般理论   2篇
预防医学   2459篇
眼科学   128篇
药学   3259篇
  3篇
中国医学   3470篇
肿瘤学   249篇
  2024年   24篇
  2023年   260篇
  2022年   385篇
  2021年   619篇
  2020年   677篇
  2019年   464篇
  2018年   441篇
  2017年   528篇
  2016年   643篇
  2015年   666篇
  2014年   976篇
  2013年   1183篇
  2012年   904篇
  2011年   1202篇
  2010年   850篇
  2009年   759篇
  2008年   761篇
  2007年   648篇
  2006年   673篇
  2005年   566篇
  2004年   425篇
  2003年   389篇
  2002年   311篇
  2001年   285篇
  2000年   204篇
  1999年   189篇
  1998年   169篇
  1997年   124篇
  1996年   133篇
  1995年   126篇
  1994年   130篇
  1993年   119篇
  1992年   128篇
  1991年   78篇
  1990年   77篇
  1989年   68篇
  1988年   64篇
  1987年   67篇
  1986年   44篇
  1985年   64篇
  1984年   49篇
  1983年   41篇
  1982年   33篇
  1981年   32篇
  1980年   33篇
  1979年   27篇
  1978年   24篇
  1977年   14篇
  1976年   14篇
  1973年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
目的 发现四物汤的新药理作用并辨识其有效成分群。方法 于GEO和Cmap数据库获取四物汤和1309个小分子药物的基因表达谱,计算差异表达基因及四物汤与1309个小分子药物的基因表达谱间的相似性,相似性较高的小分子药物的药理作用为四物汤的新药理作用。相似性较高的小分子药物的靶点作为四物汤发挥新药理作用的靶标,利用分子对接技术辨识四物汤的有效成分群。结果 四物汤具有抗乳腺癌的作用,其有效成分群为荭草苷、芍药苷和半乳糖醛酸等,并通过文献调研验证了辨识结果的可靠性。结论 本研究将为扩大四物汤的临床应用范围及质量控制奠定基础,为乳腺癌的治疗提供新方法。  相似文献   
4.
5.
6.
Intervertebral disc disease (IVDD) is a common musculoskeletal disease affecting about 5% of all individuals. It is characterized by lumbar disc herniation, which causes nerve root irritation, either mechanically or via inflammatory mediators, and results in radiating pain, known as sciatica. Numerous studies have been conducted to identify the causes and risk factors for IVDD. Lifting heavy loads, torsional stress, and motor vehicle driving are among the best-identified environmental risk factors. However, it has become evident recently from family and twin studies that genetic factors may also be important in IVDD. This hypothesis was strengthened by the identification of two collagen IX alleles associated with sciatica and lumbar disc herniation. In addition, disc degeneration has been shown to be related to an aggrecan gene polymorphism, a Vitamin D receptor and matrix metalloproteinase-3 gene alleles. This review highlights the genetic role and occupational aspects of IVDD.  相似文献   
7.
Folium Artemisiae argyi Carbonisatum (FAAC) is a traditional medicine widely used in clinic. It has the effect of hemostasis by warming meridians. In order to further explore the chemical composition and biological activity of FAAC, the methanol extract of FAAC was isolated and purified by open column and high- performance liquid chromatography. and the complete structure was characterized by nuclear magnetic resonance (NMR) and LREI-MS for the first time, namely rutin, quercetin and octacosanol respectively. Initially the toxic effect of methanol extract of FAAC on zebrafish was evaluated by observing the phenotypic characteristics, spontaneous twitch times, heart rate, hatching rate, the distance of SV-BA and cardiomyocyte apoptosis of zebrafish. The results showed that FAAC has embryonic development toxicity and cardiotoxicity when it was higher than 62.5 μg/mL. Meanwhile, the hemostatic effect of methanol extract of FAAC was compared with FAA (Folium Artemisia argyi) by zebrafish intestinal bleeding model originally. The results showed that the hemostatic effect of the medium and high concentration dose groups (3.0 and 30.0 μg/mL) was enhanced for both FAAC and FAA. This study provided an experimental basis for the clinical application of FAAC.  相似文献   
8.
9.
10.
Steady-state axisymmetric simulations using the Reynolds-Averaged Navier-Stokes equations have been carried out in order to optimize the performance of a Chemical, Biological, Radiological, and Nuclear (CBRN) canister filter for its use in a powered air-purifying respirator (PAPR). Alterations have been made to the shape of the canister, the spacing of the rear wall of the canister with regard to the carbon filter, and the bracketing between (i) the particulate filter and the carbon bed and (ii) the carbon bed and the canister wall. The pressure drops across the canister and the residence time distribution at the rear of the carbon bed have been analyzed in detail based on an extensive parametric analysis involving the aforementioned variations. It has been demonstrated that the non-uniform porosity profile of the carbon bed resulted in alternating regions of high and low velocity close to the canister wall, providing a possible route for breakthrough. Designs, which included a bracket at the rear of the carbon bed, blocked this route and consequently had a longer minimum mean residence time than those, which did not. It has also been shown that the spacing between the carbon bed and the canister rear wall had a large impact on both residence time and pressure drop. In cases where the carbon backed directly onto the canister rear wall flow in the axial direction from the outside wall toward the canister axis resulted in far greater pressure drop and a reduction in minimum mean residence time within the carbon bed.  相似文献   
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