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   420709篇
  免费   27831篇
  国内免费   8448篇
耳鼻咽喉   5012篇
儿科学   7941篇
妇产科学   9302篇
基础医学   59677篇
口腔科学   11377篇
临床医学   38027篇
内科学   78545篇
皮肤病学   8067篇
神经病学   27259篇
特种医学   14934篇
外国民族医学   120篇
外科学   58922篇
综合类   26868篇
现状与发展   24篇
一般理论   54篇
预防医学   21952篇
眼科学   10279篇
药学   37788篇
  127篇
中国医学   8350篇
肿瘤学   32363篇
  2023年   2963篇
  2022年   5722篇
  2021年   7965篇
  2020年   5995篇
  2019年   6363篇
  2018年   7611篇
  2017年   6374篇
  2016年   6318篇
  2015年   8160篇
  2014年   10639篇
  2013年   11848篇
  2012年   16335篇
  2011年   16974篇
  2010年   11202篇
  2009年   9698篇
  2008年   13602篇
  2007年   14245篇
  2006年   13624篇
  2005年   12375篇
  2004年   10801篇
  2003年   10548篇
  2002年   9761篇
  2001年   25056篇
  2000年   24970篇
  1999年   20810篇
  1998年   5360篇
  1997年   4801篇
  1996年   4037篇
  1995年   3704篇
  1994年   3312篇
  1993年   2883篇
  1992年   13522篇
  1991年   12531篇
  1990年   11904篇
  1989年   11749篇
  1988年   10571篇
  1987年   10063篇
  1986年   9293篇
  1985年   8459篇
  1984年   5728篇
  1983年   4659篇
  1982年   2369篇
  1979年   4539篇
  1978年   2818篇
  1977年   2533篇
  1975年   2190篇
  1974年   2583篇
  1973年   2388篇
  1972年   2351篇
  1971年   2323篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
Context: MOTILIPERM was prepared as a mixture of extracts of three medicinal herbs [roots of Morinda officinalis How (Rubiaceae), outer scales of Allium cepa L. (Liliaceae) and seeds of Cuscuta chinensis Lamark (Convolvulaceae)].

Objective: To investigate the role of reactive oxygen species (ROS)-based endoplasmic reticulum (ER) stress in a rat model of varicocele and the therapeutic efficacy of MOTILIPERM in this model.

Materials and methods: Sixty male rats were divided into five experimental groups: a normal control group (CTR?+?vehicle), a control group administered MOTILIPERM 200?mg/kg (CTR?+?M 200), a varicocele-induced control group (VC?+?vehicle) and two varicocele-induced groups administered MOTILIPERM 100 (VC?+?M 100) or 200 (VC?+?M 200) mg/kg for 4 weeks. Testis weights were recorded and serums were assayed for hormone concentrations. Tissues were subjected to semen analysis, histopathology, analyses of ER response protein expression levels and oxidative stress were assessed by measuring ROS, reactive nitrogen species (RNS), malondialdehyde (MDA) level and ratios of total glutathione (GSH)/oxidized GSH (GSSG).

Results: MOTILIPERM treatment of varicocele-induced groups significantly increased left testis weight, testosterone level, sperm motility, count and spermatogenic cell density. ER-response protein expression levels were dose-dependently decreased in VC?+?M 200 group compared with VC?+?vehicle group. MOTILIPERM treatment also decreased MDA and ROS/RNS level but increased GSH/GSSG ratio.

Discussion and conclusions: This study suggests that ROS-related ER stress may play a major role in varicocele-induced infertility and MOTILIPERM, a novel compound targeting ROS-based ER stress, may be therapeutically useful in treatment of varicocele, or as a supplement for the treatment of infertility.  相似文献   
34.
35.
This report describes the development of polyplexes based on CXCR4-inhibiting poly(ethylenimine) derivative (PEI-C) for pulmonary delivery of siRNA to silence plasminogen activator inhibitor-1 (siPAI-1) as a new combination treatment of pulmonary fibrosis (PF). Safety and delivery efficacy of the PEI-C/siPAI-1 polyplexes was investigated in vitro in primary lung fibroblasts isolated from mice with bleomycin-induced PF. Biodistribution analysis following intratracheal administration of fluorescently labeled polyplexes showed prolonged retention in the lungs. Treatment of mice with bleomycin-induced PF using the PEI-C/siPAI-1 polyplexes resulted in a significant down-regulation of the PAI-1 expression and decreased collagen deposition in the lung. The results of this study provide first evidence of the potential benefits of combined inhibition of CXCR4 and PAI-1 in the pulmonary treatment of PF.  相似文献   
36.
37.
目的探讨带线锚钉在手术治疗肘关节"恐怖三联征"中的临床效果。方法回顾性分析2010年1月至2017年6月期间本院手术治疗22例肘关节"恐怖三联征"患者的临床资料,根据桡骨头骨折Mason分型,Ⅰ型2例,Ⅱ型8例,Ⅲ型12例;根据尺骨冠状突骨折Regan-Morrey分型,Ⅰ型5例,Ⅱ型12例,Ⅲ型5例;22例患者均伴有内外侧副韧带损伤,并采用肘部外侧、前内侧联合入路进行手术治疗。15例患者手术后以长臂石膏托外固定1~2周,之后逐步进行肘关节被动、主动康复锻炼。7例使用可活动铰链式外固定架辅助固定的患者早期行肘关节康复锻炼。结果所有患者手术后随访6~18个月,平均12个月。末次随访时肘关节屈曲(110±10)°,伸直受限(10±4)°,前臂旋前(70±6)°,旋后(80±6)°,并对患者进行Mayo肘关节功能评分:优(≥90分)3例,良(75~89分)12例,可(60~74分)7例,优良率为68.2%。手术后2例出现异位骨化,1例出现一过性的正中神经症状,无感染、肘关节不稳定、骨折不愈合、脱位及肘关节僵硬等并发症。结论带线锚钉通过对肘关节内外侧副韧带、关节囊等软组织修复,既增加了肘关节的稳定性,同时也减少了相关并发症的发生,值得临床推广应用。  相似文献   
38.
We report a 14-year-old boy finally diagnosed with sitosterolemia, presenting with severe aortic valve stenosis. Genetic analysis revealed homozygous null mutation c.1336 C > T (p.R446X) in ABCG5 gene. His cardiac ultrasound presented aortic valve stenosis and moderate aortic regurgitation. His whole aorta computed tomography angiogram scan revealed aortic stenosis superior to the aortic valve, followed by ascending aorta dilation, whereas his coronary and peripheral arteries appeared normal. His maximum total cholesterol and low-density lipoprotein-cholesterol levels dropped dramatically after diet control, and ezetimibe was prescribed for treatment. The current case indicated that sitosterolemia may be a heterogeneous disease in clinical phenotype.  相似文献   
39.
40.
ObjectivesThe rise in carbapenem resistance among Gram-negative bacteria has renewed interest in colistin. Recently, the EUCAST-CLSI Polymyxin Breakpoints Working Group declared that broth microdilution (BMD) is the only valid method for colistin susceptibility testing. BMD is not easily incorporated into the routine work of clinical laboratories, and usually this test is incorporated serially, resulting in delayed susceptibility reporting. We tested a strategy of combining VITEK® 2 with a 2 μg/mL colistin agar dilution (VITEK® 2/AD) screening plate to improve performance and time to reporting of colistin susceptibility.MethodsColistin susceptibility for 364 clinical isolates was determined by VITEK® 2/AD and compared with the reference standard BMD according to the ISO 20776-1:2007 and CLSI guidelines. The EUCAST colistin susceptibility breakpoint of ≤2 μg/mL was used. Escherichia coli NCTC 13846 served as quality control strain. Agreement, very major error (VME) and major error rates were determined using ISO 20776-2:2007.ResultsThe VME rate for VITEK® 2 alone was 30.6% (15/49, 95% CI 18.3–45.4%), and was reduced to 10.2% (5/49, 95% CI 3.4–22.2%) using the VITEK® 2/AD combined testing. The combined testing had categorical agreement with BMD of 97% (354/364, 95% CI 95.0–98.7%), and a major error (ME) rate of 1.6% (5/315, 95% CI 0.5–3.7%). Using the combined testing, even against challenging strains, 349 (95.8%, 95% CI 93.3–97.7%) colistin susceptibility results could be reported, and only 15 isolates required further analysis by BMD.DiscussionOur method is simple to apply and allows rapid reporting of colistin susceptibility.  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