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   61334篇
  免费   6319篇
  国内免费   4295篇
耳鼻咽喉   547篇
儿科学   768篇
妇产科学   535篇
基础医学   6134篇
口腔科学   1108篇
临床医学   7055篇
内科学   8220篇
皮肤病学   658篇
神经病学   2926篇
特种医学   2406篇
外国民族医学   21篇
外科学   6595篇
综合类   12929篇
现状与发展   15篇
一般理论   1篇
预防医学   4796篇
眼科学   1388篇
药学   6629篇
  62篇
中国医学   4481篇
肿瘤学   4674篇
  2024年   101篇
  2023年   734篇
  2022年   1292篇
  2021年   2505篇
  2020年   2135篇
  2019年   1777篇
  2018年   1840篇
  2017年   1928篇
  2016年   1755篇
  2015年   2593篇
  2014年   3252篇
  2013年   3451篇
  2012年   4933篇
  2011年   5518篇
  2010年   4245篇
  2009年   3697篇
  2008年   4035篇
  2007年   3976篇
  2006年   3696篇
  2005年   3229篇
  2004年   2654篇
  2003年   2564篇
  2002年   2286篇
  2001年   1626篇
  2000年   1290篇
  1999年   950篇
  1998年   657篇
  1997年   580篇
  1996年   421篇
  1995年   382篇
  1994年   334篇
  1993年   210篇
  1992年   194篇
  1991年   200篇
  1990年   150篇
  1989年   125篇
  1988年   104篇
  1987年   89篇
  1986年   80篇
  1985年   61篇
  1984年   40篇
  1983年   20篇
  1982年   17篇
  1981年   14篇
  1980年   13篇
  1976年   15篇
  1974年   13篇
  1969年   11篇
  1968年   11篇
  1930年   11篇
排序方式: 共有10000条查询结果,搜索用时 453 毫秒
1.
正临床资料患者,男,52岁。云南省文山州丘北县人。因躯干、四肢结节、斑块5个月余,伴疼痛性结节10余天就诊。患者2019年2月因"接触油漆"后于双上肢出现结节、斑块,逐渐蔓延至双下肢、躯干,伴瘙痒,当地县中医医院考虑"过敏性皮炎",予抗过敏治疗(具体药物不详)后,结节、斑块未完全消退,偶有痒感,自用草药外洗治疗(具体药物不详),病情无好转,10天前患者四肢及躯干相继出现大小不等的结节,自觉疼痛。  相似文献   
2.
Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague–Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite–gene–enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity.  相似文献   
3.
4.
5.
目的 评价调整光学切削直径及Kappa角后对准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)后效果的影响。方法 选取2017年1月至12月在我院行LASIK手术的高度近视患者313例(626眼),根据切削直径分成两组,试验组157例314眼,切削直径设定为6.0 mm,对照组156例312眼,切削直径设定为6.5 mm。试验组患者激光切削前修正Kappa角,对照组不做修正。患者术前进行裸眼视力、主视眼确定、验光、眼压、暗室下瞳孔直径、泪液分泌试验、裂隙灯、散瞳验光、眼底检查、pentacam测量角膜厚度、角膜地形图测量角膜前后表面及Kappa角等检查。术后1 d、1周、1个月随访,并检查裸眼视力、角膜厚度、波前像差及夜间视力、光晕、眩光等情况。比较两组患者角膜厚度变化、手术所用时间以及两组患者术后的高阶像差的差异。结果 试验组与对照组患者年龄分别为18~44(24.19±5.33)岁、18~42(25.08±4.91)岁,屈光度分别为(-7.47±1.04)D、(-7.61±1.12)D。两组年龄、屈光度比较差异均无统计学意义(均为P>0.05)。试验组与对照组患者术前Kappa角分别为,X轴:(210±40)μm、(200±30)μm,Y轴:(190±30)μm、(220±40)μm,差异无统计学意义(P=0.210)。两组手术前后的角膜厚度及术后角膜基质床的厚度差异均无统计学意义(均为P>0.05)。试验组与对照组的手术时间分别为(15.56±1.89)s和(20.83±3.03)s,差异有统计学意义(P=0.000)。试验组的总高阶像差和垂直慧差的变化均明显低于对照组(均为 P<0.01),但两组间的水平慧差差异无统计学意义(P>0.05),对照组的球差低于试验组(P<0.01)。结论 LASIK手术中科学合理地调整Kappa角可有助于提高患者术后的视觉质量。  相似文献   
6.
目的通过CT影像测量了解漏斗胸Nuss矫形术前后胸廓径线的改变情况,探讨并分析Nuss矫形术对胸廓的影响及相关因素。方法对2014年1月至2018年12月郑州大学第一附属医院收治的50例行漏斗胸Nuss矫形术患儿的临床资料进行回顾性分析。50例患儿中男43例,女7例。所有患儿中存在脊柱侧弯6例,胸廓不对称12例,胸骨旋转11例。通过CT影像测量其放置矫形器前及取出矫形器后胸廓各椎体平面最大横内径及该平面胸脊间的距离,通过配对样本t检验比较矫形前后各径线的改变情况,以及通过独立样本t检验分析在不同年龄、性别、矫形时间、漏斗胸对称与否、是否合并脊柱侧弯等情况间的差异性。结果50例患儿均顺利完成矫形器置入术及矫形器拔除术,无明显术中及术后并发症,Nuss矫形后较矫形前相比,胸廓前后径在第8~12胸椎水平均较前增加,第3~5胸椎平面较前减小,胸廓横径在第8~10胸椎平面较前减小;年龄≤10岁、矫形时长≥2年及女性患儿胸廓前后径改变量在多个胸椎平面分别较年龄>10岁、矫形时长<2年及男性患儿大,P<0.05,差异具有统计学意义。结论漏斗胸Nuss矫形后前胸壁凹陷较前明显改善,并且在不同年龄和不同矫形时长间存在差异性,年龄较小及适当增加矫形时间可获得较好的矫形效果,而胸廓横径生长在一定程度上受限。  相似文献   
7.
8.
目的:探讨改良三点式重睑术的临床应用疗效。方法:2012年6月-2019年6月,共165例单睑患者采用了改良三点式重睑术,沿术前标记线将三点处皮肤切开,剪刀将切口下唇的眼轮匝肌适当去除,同时将切口与切口在皮下层打通,剪除切口与切口之间的眼轮匝肌,6-0可吸收线挂睑板前筋膜或提上睑肌腱膜及切口下唇皮下组织缝合,三点切口各缝1针。再用6-0单丝尼龙线按照常规重睑线缝合方法挂切口下唇皮肤、睑板前筋膜或提上睑肌腱膜及切口上唇皮肤缝合打结,三点切口各缝1针。伴内眦赘皮者同时行内眦赘皮矫正术。结果:152例患者获得随访,随访患者大部分获得了比较满意的重睑,睁眼重睑流畅、自然,闭眼刀口痕迹不明显。2例患者出现内侧重睑线变浅,1例患者出现外侧重睑线变浅,所有患者均未出现重睑消失。5例患者双侧重睑线有轻度不对称。患者总体满意率为94.7%(144/152)。结论:改良三点式重睑术具有创伤小、并发症少、效果逼真、不易脱落、手术痕迹不明显等优点,值得推广应用。  相似文献   
9.
The present study compared the level of occupational strain and work ability among Han, Hui, Uygur, Hui, and Kazakh teachers, and explored ethnic differences based on the associations of psychosocial factors at work, occupational strain, and work ability. A cross-sectional survey was conducted among 2,941 teachers in primary and secondary schools in Xinjiang Province, China. Psychosocial factors, occupational strain, and work ability were measured using the Occupation Stress Inventory—Revised Edition (OSI-R) and Work Ability Index. Han and Hui teachers experienced reduced work ability compared with Uygur and Kazakh teachers, and this finding was caused, in part, by exposure to psychosocial factors at work. The vocational and psychological strains caused by these factors play an important role in reduced work ability among all ethnic teacher groups. The findings indicate the importance of taking action to reduce occupational strain for promoting teachers' work ability in multiethnic workplaces.  相似文献   
10.
BackgroundIn the field of transplantation, inducing immune tolerance in recipients is of great importance. Blocking co-stimulatory molecule using anti-CD28 antibody could induce tolerance in a rat kidney transplantation model. Myeloid-derived suppressor cells (MDSCs) reveals strong immune suppressive abilities in kidney transplantation. Here we analyzed key genes of MDSCs leading to transplant tolerance in this model.MethodsMicroarray data of rat gene expression profiles under accession number GSE28545 in the Gene Expression Omnibus (GEO) database were analyzed. Running the LIMMA package in R language, the differentially expressed genes (DEGs) were found. Enrichment analysis of the DEGs was conducted in the Database for Annotation, Visualization and Integrated Discovery (DAVID) database to explore gene ontology (GO) annotation and their Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Their protein-protein interactions (PPIs) were provided by STRING database and was visualized in Cytoscape. Hub genes were carried out by CytoHubba.ResultsThree hundred and thirty-eight DEGs were exported, including 27 upregulated and 311 downregulated genes. The functions and KEGG pathways of the DEGs were assessed and the PPI network was constructed based on the string interactions of the DEGs. The network was visualized in Cytoscape; the entire PPI network consisted of 192 nodes and 469 edges. Zap70, Cdc42, Stat1, Stat4, Ccl5 and Cxcr3 were among the hub genes.ConclusionsThese key genes, corresponding proteins and their functions may provide valuable background for both basic and clinical research and could be the direction of future studies in immune tolerance, especially those examining immunocyte-induced tolerance.  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