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   3469126篇
  免费   266423篇
  国内免费   12718篇
耳鼻咽喉   48059篇
儿科学   112150篇
妇产科学   95920篇
基础医学   500330篇
口腔科学   98530篇
临床医学   318297篇
内科学   659389篇
皮肤病学   75287篇
神经病学   273769篇
特种医学   132936篇
外国民族医学   972篇
外科学   518843篇
综合类   94698篇
现状与发展   36篇
一般理论   1302篇
预防医学   271970篇
眼科学   82351篇
药学   264410篇
  121篇
中国医学   12099篇
肿瘤学   186798篇
  2019年   29725篇
  2018年   39639篇
  2017年   30703篇
  2016年   33766篇
  2015年   39634篇
  2014年   54945篇
  2013年   79564篇
  2012年   109323篇
  2011年   116451篇
  2010年   69355篇
  2009年   64862篇
  2008年   107255篇
  2007年   113664篇
  2006年   114954篇
  2005年   111977篇
  2004年   106483篇
  2003年   101747篇
  2002年   98796篇
  2001年   153432篇
  2000年   158139篇
  1999年   133855篇
  1998年   38040篇
  1997年   33637篇
  1996年   33026篇
  1995年   33654篇
  1994年   31200篇
  1993年   29110篇
  1992年   106333篇
  1991年   104028篇
  1990年   101483篇
  1989年   97952篇
  1988年   90638篇
  1987年   88958篇
  1986年   84040篇
  1985年   80928篇
  1984年   60515篇
  1983年   51859篇
  1982年   30709篇
  1979年   56757篇
  1978年   40134篇
  1977年   33607篇
  1976年   32058篇
  1975年   34287篇
  1974年   41545篇
  1973年   39744篇
  1972年   37113篇
  1971年   35046篇
  1970年   32312篇
  1969年   30698篇
  1968年   28075篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
91.
Purpose: The medicinal plant Ipomoea aquatica belonging to convulvulaceae family is an effective natural herb for treatment of various ailments and possesses effective anticancer activity. The aim of the work is to characterize a secondary metabolite merromoside (a resin glycoside) for anti-breast cancer activity through down regulation of ROS species. Methods: The Extract of the whole plant has been prepared by maceration method using 50%v/v ethanol in distilled water to get a hydroalcoholic extract. The phytochemical evaluation reveals that the active secondary metabolite was isolated by using column chromatographic technique. The isolated compound was evaluated for its anticancer properties through invitro method such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay on Michigan Cancer Foundation-7 Cell lines. The purity and structural characterization were done by high-performance thin layer chromatography, Fourier Transform Infrared Spectroscopy, Proton and13C Nuclear Magnetic Resonance spectroscopy and Liquid Chromatography–Mass Spectrometry. Results: The isolated compound (W04) from the derived extract showed Rf value of 0.79 that showed IC50 of 182.8μg/ml. The chemical structure of W04 has been confirmed as [4,5-dihydroxy-6-[5-hydroxy-2-methyl-4-(2-methylpropanoyloxy)-6-[(24,25,26-trihydroxy-5,23-dimethyl-9-oxo-19-pentyl-2,4,8,20,22-pentaoxatricyclo[19.2.2.13,7]hexacosan-6-yl)oxy]oxan-3-yl]oxy-2-methyloxan-3-yl] 2-methyl propanoate with the molecular weight of 979.15268. The isolated compound merromoside from hydroalcoholic extract of Ipomoea aquatica has been evaluated for anti-breast cancer properties. The down regulation of ROS species will prevent reverse signalling and angiogenesis. This indicates that merromoside will overcome MDR in breast cancer especially DOX-resistant.  相似文献   
92.
93.
94.
95.
96.
97.
98.
99.
The Dutch Drug Rediscovery Protocol (DRUP) and the Australian Cancer Molecular Screening and Therapeutic (MoST) Program are similar nonrandomized, multidrug, pan-cancer trial platforms that aim to identify signals of clinical activity of molecularly matched targeted therapies or immunotherapies outside their approved indications. Here, we report results for advanced or metastatic cancer patients with tumors harboring cyclin D-CDK4/6 pathway alterations treated with CDK4/6 inhibitors palbociclib or ribociclib. We included adult patients that had therapy-refractory solid malignancies with the following alterations: amplifications of CDK4, CDK6, CCND1, CCND2 or CCND3, or complete loss of CDKN2A or SMARCA4. Within MoST, all patients were treated with palbociclib, whereas in DRUP, palbociclib and ribociclib were assigned to different cohorts (defined by tumor type and alteration). The primary endpoint for this combined analysis was clinical benefit, defined as confirmed objective response or stable disease ≥16 weeks. We treated 139 patients with a broad variety of tumor types; 116 with palbociclib and 23 with ribociclib. In 112 evaluable patients, the objective response rate was 0% and clinical benefit rate at 16 weeks was 15%. Median progression-free survival was 4 months (95% CI: 3-5 months), and median overall survival 5 months (95% CI: 4-6 months). In conclusion, only limited clinical activity of palbociclib and ribociclib monotherapy in patients with pretreated cancers harboring cyclin D-CDK4/6 pathway alterations was observed. Our findings indicate that monotherapy use of palbociclib or ribociclib is not recommended and that merging data of two similar precision oncology trials is feasible.  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