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   1568511篇
  免费   167528篇
  国内免费   83551篇
耳鼻咽喉   12224篇
儿科学   16583篇
妇产科学   15236篇
基础医学   118813篇
口腔科学   33717篇
临床医学   204381篇
内科学   158240篇
皮肤病学   14408篇
神经病学   51455篇
特种医学   55735篇
外国民族医学   597篇
外科学   143234篇
综合类   347879篇
现状与发展   360篇
一般理论   41篇
预防医学   179558篇
眼科学   37874篇
药学   213745篇
  2870篇
中国医学   126520篇
肿瘤学   86120篇
  2024年   5393篇
  2023年   29399篇
  2022年   65339篇
  2021年   78094篇
  2020年   75343篇
  2019年   46512篇
  2018年   48001篇
  2017年   36419篇
  2016年   43125篇
  2015年   41403篇
  2014年   140169篇
  2013年   130253篇
  2012年   191189篇
  2011年   187780篇
  2010年   131114篇
  2009年   104840篇
  2008年   79858篇
  2007年   92488篇
  2006年   72694篇
  2005年   48298篇
  2004年   40707篇
  2003年   34579篇
  2002年   26243篇
  2001年   19840篇
  2000年   13492篇
  1999年   6765篇
  1998年   4393篇
  1997年   3568篇
  1996年   2909篇
  1995年   2410篇
  1994年   1842篇
  1993年   1416篇
  1992年   2003篇
  1991年   1752篇
  1990年   1668篇
  1989年   1365篇
  1988年   1393篇
  1987年   1255篇
  1986年   1081篇
  1985年   395篇
  1984年   600篇
  1983年   334篇
  1982年   420篇
  1981年   483篇
  1980年   263篇
  1979年   84篇
  1978年   142篇
  1977年   109篇
  1976年   114篇
  1974年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
BACKGROUND: The ubiquitin-proteasome system (UPS) is thought to be functionally active in atherosclerosis (AS) lesions. Aspirin was found to be a potent inhibitor of the UPS in some tumour studies; however, its effect on AS remains to be demonstrated in vivo. METHODS: New Zealand rabbits were placed on a normal diet (N) or on a normal diet with aspirin (NI) or on an atherogenic diet without (H) or with aspirin (HI) for 12 weeks. Proteasome activity, concentrations of plasma lipids and levels of peroxidation were determined. Ubiquitin/ubiquitin-conjugates (Ub), IkappaBalpha, phosphorylated IkappaB (pIkappaBalpha) and p65 were investigated by Western blotting or immunochemistry. RESULTS: Concentrations of plasma lipids and peroxidation levels were higher in H or HI vs. N or NI. Histological analysis showed that atheroma was increased in H. Ub and IkappaBalpha were mainly localised in subendothelium and media vascular smooth muscle cells. Western blots revealed that Ub, IkappaBalpha, and pIkappaBalpha were increased, whereas p65 was lower in HI vs. H. The activity of the 20S proteasome was functionally active in H vs. N, NI or HI, while the 26S proteasome was not affected in any of the groups. CONCLUSIONS: Aspirin can attenuate the pathogenesis of atheroma formation, the degradation of IkappaBalpha and pIkappaBalpha, and lower the expression of p65, indicating that its therapeutic effects on AS may be via inhibition of the UPS.  相似文献   
92.
AIM: To report the treatment of a recurrent adenoid-cystic carcinoma of the lacrimal gland required orbital exenteration with an en bloc resection of the lateral orbital rim and wall and an anterior portion of the temporal muscle. Reconstruction was planned with both the objectives of a shortened healing time for faster epithetic reconstruction and no visible scars. METHOD: After a cranially extended temporal approach, the dissection of the superficial galea layer was connected with the subcutaneous dissection of the upper and lower eyelid after subciliary incisions. RESULTS: Ample exposure of the temporal, frontal and orbital region was obtained, facilitating the orbital exenteration with en bloc resection of the lateral orbital rim and wall and the anterior portion of the temporal muscle. The epithelialization of the eye socket covered with the galea fascia flap was accelerated, providing faster epithetic reconstruction, without visible scars. CONCLUSIONS: Healing time is accelerated, providing faster epithetic rehabilitation without visible scars, which is important in the postoperative rehabilitation ladder after eye exenteration for both patient and surgeon. Further more ablative surgery within this region gets safer and easier due to the ample exposure of this innovative surgical technique. Further evaluation of the effectiveness and safety of this new approach is advisable.  相似文献   
93.
94.
Regulatory T cells (Tregs) play important roles in the maintenance of immune homeostasis, and is also involved in tumor immune tolerance. Dampening or elimination of Treg functions has been shown to lead to enhanced immune responses against tumors, and thus inhibition of tumor growth. Recently, we have developed a new immunization scheme, referred to as irradiated mitogen-activated autologous T cell vaccination (ATCV), and shown that such immunization could significantly enhance anti-tumor immunity in vivo. Mechanistically, the enhanced anti-tumor response appears to be due to reduced Treg functions and inhibition of activation-induced cell death (AICD) in effector T cells. Thus, ATCV may constitute a novel strategy in cancer immune therapy.  相似文献   
95.
96.
Abstract: The aim of this study was to evaluate in vitro the dose‐dependent induction potential of six commonly used trade herbal products on CYP2C19 and CYP2E1 metabolic activities in cultured human hepatocytes. S‐mephenytoin and chlorzoxazone were used as specific CYP substrates, respectively, and rifampicin was used as a positive induction control for both enzymes. The hepatocytes were exposed to herbal extracts in increasing and biological relevant concentrations for 72 hrs and CYP substrate metabolites were quantified by validated HPLC methodologies. The major findings were that St John's wort was the most potent CYP‐modulating herb, showing a dose‐dependent induction/inhibition of both CYP2C19 and CYP2E1, with induction at low dosages and inhibition at higher. Ginkgo biloba showed an induction/inhibition profile towards CYP2C19 which was similar but weaker than that observed for St John's wort. If cooperative mechanisms are involved is still an open question. Common sage induced CYP2C19 in a log‐linear dose‐dependent manner with increasing concentrations. Common valerian was a weak inducer of CYP2C19, while horse chestnut and cone flower were characterized as non‐inducers of CYP2C19. Only St John's wort showed an inductive effect towards CYP2E1. In addition to St John's wort, Gingko biloba and common sage should be considered as possible candidates for clinically relevant drug‐herb interactions with selected CYP2C19 substrates.  相似文献   
97.
急诊抗菌药物的使用调查与分析   总被引:1,自引:0,他引:1  
目的考察了解急诊抗菌药物的使用情况。方法随机抽取2008年7—12月的急诊处方2700张,对其中抗菌药物的应用情况进行统计分析。结果急诊抗菌药物使用率49.1%,药物应用形式以单用为主(占66.3%);给药途径以口服和静脉注射为主。不合理用药处方占抗菌药物处方的10.8%,分别在选药方案、给药方案、溶媒使用、联合应用等方面存在问题。结论我院急诊抗菌药物的应用基本合理,但仍存在一定问题,需进一步加强管理。  相似文献   
98.
目的探讨中药健肝愈胃汤(自拟)、西药心得安、奥美拉唑、胶态果胶铋胶囊联合治疗门脉高性胃病(PHG)的疗法。方法将136例PHG患者随机分成两组,对照组52例常规口服心得安、奥美拉唑、果胶铋;治疗组84例在常规服用以上西药的同时服用中药健肝愈胃汤。两组疗程均为2个月。结果治疗组临床治疗总有效率89.3%。显效率46.4%;对照组临床治疗总有效率80.7%,显效率13.5%。两组比较有显著性差异(P〈0.05)。结论中药健肝愈胃汤、西药心得安、奥美拉唑、果胶铋联合治疗PHG疗效显著。  相似文献   
99.
100.
目的介绍一种简单、快速的真菌DNA提取方法,提高真菌DNA提取效率,减少毒性和污染性,以适应临床研究需要。方法同时用溶细胞酶结合Biospin真菌基因组DNA提取试剂盒和十六烷基三甲基溴化铵(CTAB)法,提取白色念珠菌、热带念珠菌、克柔念珠菌和净平滑念珠菌基因组DNA,用A260/A280的比值检测DNA的纯度并计算质量浓度,同时行聚合酶链反应(PCR)以评价其可靠性。结果溶细胞酶结合Biospin真菌基因组DNA提取试剂成功提取所用真菌基因组DNA,其纯度及质量浓度能满足PCR反应的要求。结论用溶细胞酶结合Biospin真菌基因组DNA提取试剂提取DNA,简单、快速、高效,可用于PCR反应。  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