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   219004篇
  免费   18088篇
  国内免费   8029篇
耳鼻咽喉   1249篇
儿科学   4136篇
妇产科学   2273篇
基础医学   35336篇
口腔科学   3648篇
临床医学   20431篇
内科学   36062篇
皮肤病学   2519篇
神经病学   9762篇
特种医学   4401篇
外国民族医学   32篇
外科学   16220篇
综合类   34079篇
现状与发展   29篇
一般理论   25篇
预防医学   16507篇
眼科学   4632篇
药学   24493篇
  33篇
中国医学   11163篇
肿瘤学   18091篇
  2024年   420篇
  2023年   2526篇
  2022年   5497篇
  2021年   7396篇
  2020年   6649篇
  2019年   7088篇
  2018年   6883篇
  2017年   6843篇
  2016年   7319篇
  2015年   7637篇
  2014年   12056篇
  2013年   13275篇
  2012年   11768篇
  2011年   13195篇
  2010年   11209篇
  2009年   10906篇
  2008年   10923篇
  2007年   11900篇
  2006年   10878篇
  2005年   10437篇
  2004年   8990篇
  2003年   7922篇
  2002年   6004篇
  2001年   5771篇
  2000年   4649篇
  1999年   4258篇
  1998年   3206篇
  1997年   2801篇
  1996年   2795篇
  1995年   2732篇
  1994年   2386篇
  1993年   2109篇
  1992年   1858篇
  1991年   1593篇
  1990年   1352篇
  1989年   1262篇
  1988年   1160篇
  1987年   911篇
  1986年   697篇
  1985年   1022篇
  1984年   1072篇
  1983年   748篇
  1982年   862篇
  1981年   717篇
  1980年   642篇
  1979年   557篇
  1978年   442篇
  1977年   356篇
  1976年   408篇
  1975年   298篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
医院用血液制品HCV污染情况的调查   总被引:1,自引:0,他引:1  
目的调查医院治疗用血液制品HCV污染情况.方法临床治疗所用的血液制品,在输完后留容器之残液备检.采用酶标免疫法(ELISA)检测.对ELISA检测之阳性标本及在阴性标本中随机抽取9份,采用逆转录双PCR方法检测HCV_RNA.结果血浆白蛋白抗_HCV阳性率458%,新鲜血浆阳性率26%.两种方法检测同一标本,ELISA检测阳性的血液制品中,用PCR证实,并非都有病毒复制;而在ELISA检测的阴性标本中,仍旧有较高的PCR阳性检出.结论血液制品存在着HCV污染,抗_HCV对于HCV感染的诊断价值很高.检测血液制品中的抗_HCV,合理使用血液成份,可防止HCV在医院内传播.  相似文献   
992.
A cohort study was undertaken to compare the effect at the timeof oocyte retrieval of the i.v. administration of either 1000ml of lactated Ringer' solution or 1000 ml of a 5% solutionof human albumin on in-vitro fertilization patients at riskfor severe ovarian hyperstimulation syndrome (OHSS). A totalof 207 patients with an oestradiol concentration > 10 000pmol/l and/or > 15 follicles (>10 mm diameter) on theday of human chorionic gonadotrophin (HCG) injection were reviewed.Of these, 158 women received 500 ml of lactated Ringer’ssolution both before and after egg retrieval, and 49 women receivedtwo infusions of 500 ml of 5% human albumin in normal salineat the time of egg retrieval. Severe OHSS developed in two patientswho received human albumin and in 10 women who did not receivethe albumin. This difference was not statistically significant.There were no differences between the two groups in terms ofage, number of follicles punctured at transvaginal oocyte retrievalor oestradiol concentration at the time of HCG injection. Theadministration of a 5% human albumin solution does not preventthe development of severe OHSS in at risk patients. It doesappear to blunt the severity of the condition.  相似文献   
993.
采用 Mark-600型超声诊断仪测量了128例高血压病患者主动脉壁厚度(AWT),并同时检测了血脂指标,结果显示,高脂血症组血清 apoB 及 AWT 均显著高或厚于血脂正常组(P<0.01),其 apoAI/apoB 比值显著低于血脂正常组(P<0.01),临床合并冠心病的患病率亦显著高于血脂正常组(P<0.05)。相关性分析显示,AWT 与 apoB(r=0.338)呈直线正相关,与 apoAl(r=-0.385)及apoAl/apoB(r=-0.540),呈直线负相关,(P 均<0.01)。经逐步回归分析,筛选对 AWT 有显著作用的血脂指标,结果依次为 apoAl/apoB、apoB。  相似文献   
994.
The thymoma-prone rat of the BUF/Mna strain is a useful model for human thymoma. In this strain thymoma development is regulated by a single autosomal susceptible gene, Tsr-1. At pre-thymoma age, BUF/Mna rats have extremely large thyrauses, when compared to those of other strains of rats. Genetic studies in crosses between BUF/Mna rats with large thymuses and WKY/NCrj rats with small thymuses suggested the presence of a major autosomal gene, Ten-1 , which contributes to thymus enlargement in a backcross population. Linkage studies between Ten-1 and microsatellite markers in backcross rats of (WKY/NCrj×BUF/Mna)Fl×BUF/Mna have led to the localization of Ten-1 in chromosome 1. This result may provide an approach to clone Tsr-1 , which could be allelic to Ten-1.  相似文献   
995.
用基因工程重组的丙肝抗原包被于硝酸纤维素膜,建立了检测丙肝IgG抗体的斑点免疫渗滤法。与ELISA试剂盒进行双盲式同步测定,二法检验结果差异无显著性。渗滤法简便快速,适用于各级医院,有很强的推广价值。  相似文献   
996.
本文采用超凝胶柱层析法分离纯化日本血吸虫成虫31/32KD抗原。分离的抗原经银染色及免疫印迹法分析证明已达免疫纯及生化纯级。该抗原PAS染色呈阴性,经过碘酸钠处理后不失去活性,在琼脂糖凝胶电泳中趋向阳极。鉴于血吸虫成虫31/32KD组分是一种主要血清学抗原,它的分离纯化为改进和标化血吸虫病的诊断提供了条件。  相似文献   
997.
The electrochemical behavior of porous TiN coating for defibrillator electrodes was investigated by in vitro studies. A commercially available Ti patch was compared with a Ti patch coated with a layer of porous TiN. Similarly, the influence of the TiN coating on a Pt/Ir intracardial electrode was tested. Porous TiN coatings were made by reactive sputtering on the plain electrodes. Electrode potential measurements were performed during monophasic anodic and cathodic defibrillator shocks delivering energies between 1 J and 49 J. Porous TiN coating of Pt/Ir coils was found suitable to deliver cathodal pulses, while a plain coil remains recommended for anodic shocks. TiN coating was of benefit for conventional Ti patches. Particularly, in the case of anodic shocks, the TiN layer protected the Ti-mesh from immediate oxidation. However, above 70 anodic shocks of 49 J, the TiN coating underwent oxidation to an oxynitride. An estimated 180 anodic shocks of 10 J could be delivered before TiN oxidation became measurable by increased polarization.  相似文献   
998.
Using B cells from the transgenic mouse line B6-Sp6 and control littermates, stimulated by lipopolysaccharide (LPS) under novel culture conditions that provide for the response of all B cells, we show here that specific ligation of the surface IgM molecules always results in inhibition of terminal differentiation and immunoglobulin secretion by activated cells, regardless of the ligand. Thus, monoclonal antibodies to (a) the CH region of Ig (anti-μ. and anti-allotype), (b) the Cx region, (c) the V region (anti-idiotype) of surface IgM, as well as (d) multivalent antigen (2,4,6-trinitrophenyl-bovine serum albumin), all show similar effects and dose-response curves. IgD-negative transgenic B cells are equally sensitive to IgM ligation-dependent inhibition, as control (IgD-positive) B cells. The allotype specificity of this inhibition, assessed by using anti-u, allotype reagents to inhibit and assay the responses, suggests that B cells expressing transgenic or endogenous IgM in transgenic B6-Sp6 mice are largely independent populations. These observations establish that anti-IgM antibodies in conjunction with appropriate LPS stimulation, provide a universal model system for functional characterization of B cell responses.  相似文献   
999.
柯萨奇病毒诱发实验性多发性肌炎的初步研究   总被引:4,自引:0,他引:4  
分别用不同量的柯萨奇病毒B1、2、3感染和兔肌匀浆加完全弗氏佐剂免疫正常豚鼠;拟建立多发性肌炎模型。结果发现:0.1ml毒力为10-5TCID50柯萨奇病毒B1感染豚鼠组,3周后出现多发性肌炎症状。肌酶谱异常与其它组有明显差异,病理检查证实为多发性肌炎改变。单纯兔肌匀浆免疫对照组未发病。提示柯萨奇病毒B1感染及感染的病毒量与多发性肌炎的发病相关  相似文献   
1000.
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