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   12437篇
  免费   859篇
  国内免费   49篇
耳鼻咽喉   84篇
儿科学   307篇
妇产科学   270篇
基础医学   2074篇
口腔科学   96篇
临床医学   1243篇
内科学   2741篇
皮肤病学   194篇
神经病学   1344篇
特种医学   351篇
外科学   1361篇
综合类   60篇
一般理论   2篇
预防医学   941篇
眼科学   218篇
药学   841篇
中国医学   22篇
肿瘤学   1196篇
  2024年   10篇
  2023年   100篇
  2022年   163篇
  2021年   342篇
  2020年   220篇
  2019年   318篇
  2018年   412篇
  2017年   263篇
  2016年   259篇
  2015年   324篇
  2014年   467篇
  2013年   602篇
  2012年   1030篇
  2011年   1008篇
  2010年   548篇
  2009年   569篇
  2008年   887篇
  2007年   899篇
  2006年   806篇
  2005年   805篇
  2004年   716篇
  2003年   688篇
  2002年   664篇
  2001年   106篇
  2000年   101篇
  1999年   95篇
  1998年   110篇
  1997年   106篇
  1996年   82篇
  1995年   62篇
  1994年   55篇
  1993年   47篇
  1992年   51篇
  1991年   48篇
  1990年   32篇
  1989年   40篇
  1988年   41篇
  1987年   26篇
  1986年   34篇
  1985年   28篇
  1984年   18篇
  1983年   23篇
  1982年   16篇
  1981年   13篇
  1978年   13篇
  1976年   9篇
  1975年   8篇
  1973年   9篇
  1971年   7篇
  1969年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.  相似文献   
5.
There is increasing public interest in natural or herbal-based healthcare products. This trend is not only visible in supermarkets and dental practices, but also in the scientific world. An improving number of clinical trials are being conducted to validate the claims made about these products in regards to periodontal health. Among single component preparations, Aloe vera and green tea are the most studied natural ingredients. Concerning polyherbal mixtures, triphala has garnered great interest. The effects of these natural products on periodontal health is encouraging, with almost all studies showing an inhibitory effect on plaque accumulation and an improvement in gingival health. However, more studies are needed to be able to design clinical guidelines to guide the use of these natural products in periodontal practice. For most of these products, few studies are available and, moreover, the available studies are limited in duration, the number of participants, and the specific composition of the natural product is often not described in detail.  相似文献   
6.
7.
8.
Ovarian carcinoma is one of the most lethal malignancies, but only very few prognostic biomarkers are known. The degradome, comprising proteases, protease non-proteolytic homologues and inhibitors, have been involved in the prognosis of many cancer types, including ovarian carcinoma. The prognostic significance of the whole degradome family has not been specifically studied in high-grade serous ovarian cancer. A targeted DNA microarray known as the CLIP-CHIP microarray was used to identify potential prognostic factors in ten high-grade serous ovarian cancer women who had early recurrence (<1.6 years) or late/no recurrence after first line surgery and chemotherapy. In women with early recurrence, we identified seven upregulated genes (TMPRSS4, MASP1/3, SPC18, PSMB1, IGFBP2, CFI – encoding Complement Factor I – and MMP9) and one down-regulated gene (ADAM-10). Using immunohistochemistry, we evaluated the prognostic effect of these 8 candidate genes in an independent cohort of 112 high-grade serous ovarian cancer women. Outcomes were progression, defined according to CA-125 criteria, and death. Multivariate Cox proportional hazard regression models were done to estimate the associations between each protein and each outcome. High ADAM-10 expression (intensity of 2–3) was associated with a lower risk of progression (adjusted hazard ratio (HR): 0.51; 95% confidence interval (CI): 0.29-0.87). High complement factor I expression (intensity 2–3) was associated with a higher risk of progression (adjusted HR: 2.30, 95% CI: 1.17–4.53) and death (adjusted HR: 3.42; 95% CI: 1.72–6.79). Overall, we identified the prognostic value of two proteases, ADAM-10 and complement factor I, for high-grade serous ovarian cancer which could have clinical significance.  相似文献   
9.
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