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   34474篇
  免费   3279篇
  国内免费   2183篇
耳鼻咽喉   349篇
儿科学   510篇
妇产科学   427篇
基础医学   4000篇
口腔科学   692篇
临床医学   4369篇
内科学   5347篇
皮肤病学   381篇
神经病学   1916篇
特种医学   1445篇
外国民族医学   12篇
外科学   3989篇
综合类   4969篇
现状与发展   6篇
一般理论   3篇
预防医学   2168篇
眼科学   907篇
药学   3541篇
  27篇
中国医学   1634篇
肿瘤学   3244篇
  2024年   95篇
  2023年   472篇
  2022年   1169篇
  2021年   1506篇
  2020年   1124篇
  2019年   1117篇
  2018年   1173篇
  2017年   1086篇
  2016年   1110篇
  2015年   1495篇
  2014年   1840篇
  2013年   1735篇
  2012年   2279篇
  2011年   2686篇
  2010年   1702篇
  2009年   1347篇
  2008年   1804篇
  2007年   1867篇
  2006年   1808篇
  2005年   1735篇
  2004年   1368篇
  2003年   1356篇
  2002年   1199篇
  2001年   972篇
  2000年   906篇
  1999年   840篇
  1998年   472篇
  1997年   535篇
  1996年   367篇
  1995年   319篇
  1994年   249篇
  1993年   211篇
  1992年   272篇
  1991年   250篇
  1990年   219篇
  1989年   196篇
  1988年   170篇
  1987年   166篇
  1986年   141篇
  1985年   94篇
  1984年   62篇
  1983年   46篇
  1982年   30篇
  1981年   23篇
  1980年   32篇
  1979年   54篇
  1978年   25篇
  1976年   22篇
  1975年   26篇
  1974年   29篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
为探讨细胞外间质主要成分透明质酸(HA)与层粘连蛋白(LN)在缺血性股骨头坏死(INFH)中的生理病理过程及临床价值,采用放射免疫分析法对45例不同病因的INFH患者进行了血清HA与LN的定量分析,并与30例正常人对照。结果显示,INFH患者血清HA含量极显著地高于对照组(t=3-29;P<0-01)。尤以激素性INFN增高最为显著(t=3-62;P<0-01)。INFH患者LN含量亦明显高于对照组(t=2-84;P<0-01)。同时,HA与LN含量增高与病程发展密切相关。故定量检测HA与LN可作为INFH早期诊断及判断预后的良好指标  相似文献   
112.
Wang ZH  Liao YH  Fu M 《Autoimmunity》2001,34(4):241-245
The aim of this study was to examine the frequency of occurrence of autoantibodies against beta1-adrenoceptors in patients with hepatitis virus myocarditis (HVM) and its possible correlation with clinical characteristics. A total of 103 patients with viral myocarditis were divided into a positive group (HVM group, n=29) and a negative group (Non-HVM group, n=74) according to the laboratory findings regarding their type of hepatitis virus. The study parameters included UCG, ECG, biochemical findings and screening of autoantibodies against beta1-adrenoceptor. It was shown that the positive rate of the hepatitis virus was 28.16% (29/103) in patients with viral myocarditis. The severity of myocardial or liver injuries and the frequency of occurrence of autoantibodies against beta1-adrenoceptors in patients with viral myocarditis were more pronounced, before treatment, in the HVM group than in the Non-HVM group. The positive rates of the antibodies against the hepatitis virus and the autoantibodies against beta1-adrenoceptors were highly consistent in patients with HVM (p<0.05). In conclusion, the frequency of occurrence of the autoantibodies against beta1-adrenoceptors may be one important marker of HVM and, thus, possibly involved in the pathogenesis of the HVM.  相似文献   
113.
Intending to clarify the true Incidence of Invasive lobular carcinoma of the breast In Japanese women as well as the frequency of unilateral multlcentriclty, 362 cases of clinically defined monocentrlc breast cancer without pre-operative biopsy (previously fine needle aspiration or needle biopsy were routinely carried out for every case) were examined by whole mammary gland serial sectioning. On the basis of pathology and the World Health Organization classification of breast tumors, each case was assigned to one of two main histologlc types: Invasive lobular carcinoma (ILC) or Invasive ductal carcinoma (IDC). Invasive lobular carcinoma was further separated into classic and variant types by employing previously published criteria. Twenty-one cases of ILC (5.8%) were diagnosed, which Is more than In most previous Japanese studies. Unilateral multicentric breast carcinoma was detected In 9.5% of ILC and 16.1% of IDC (the difference was found not significant). Microscopically, ILC tumors were found to be, on average, larger than IDC. Patients with classic type ILC tended to be younger than those with variant type or IDC. Estrogen receptor expression was found more frequently In variant type ILC than in classic type. These results suggest that the incidence of invasive lobular carcinoma of the breast In Japanese women is low and that unilateral multicentricity Is not significantly higher in ILC than in IDC.  相似文献   
114.
为给神经末梢冷冻治疗跟痛提供穿刺定位依据,在52侧下肢中对跟内侧支和跟外侧支的体表投影进行了观测。跟内侧支约有69.8%通过内踝跟结节线的中份,另有28.3%跟内侧支起于该线中份下方距离7.3mm处;跟外侧支约有70.2%通过外踝跟结节线的中份,另有22.8%跟外侧支起于该线下方距离5.8mm 处。据此冷冻治疗跟痛的进针部位可以选在内、外踝与跟结节连线的中份下方垂直距离5mm 处。  相似文献   
115.
By inducing delayed type hypersensitivity (DTH) responses under previously formed skin blisters we determined that cells which mediate natural killer (NK) like cytotoxicity are present in the DTH response in man. Similar levels of killing were not present in cells obtained from skin blisters not associated with positive DTH responses. The DTH response associated killer cell was found to be a mononuclear cell that had presumably undergone stimulation since it not only killed NK sensitive K-562 cells, but also NK resistant Daudi target cells.  相似文献   
116.
用放射免疫分析法和比浊法测定PAI0134对大鼠血浆血栓素B2浓度,血小板TXB2生成血小板聚集的影响。静脉注射API013470mg或100mg.kg显著降低血浆TXB2浓度,其降低2率分别为38.8%和51.6%,API0134明显抑制ADP诱导的大鼠血小板聚集和TXB2生成,抑制率分别为27.8%,39.5%,和41.4%,53.6%,两抑制率间呈显著正相关。  相似文献   
117.
118.
利用PCR方法,从阴离子交换蛋白1(AE1)全长cDNA中扩增出约350bp c末端cDNA片段,测序后将其克隆至pGADT7载体上,用醋酸锂法构建好的pADT7-AE1-c末端转染酵母菌HA109,观察其在选择性培养基上的表达情况。结果表明,获得了530bp AE1c-末端cDNA,pGADT7-AE1-c末端对酵母无毒性,不能激活检测基因,可作为酵母双杂合系统中的靶基因。  相似文献   
119.
120.
Many residues involved in polymorphic antibody-binding epitopes on class II molecules are located on the -helix of DRβ chains. Although they have received less attention, residues in the peptide-binding groove and second domain of the DRβ chain may also be critical for polymorphic anti-DR antibody epitopes. In this study, we used transfectants expressing site-directed mutations at positions in the HLA-DR β1 and β2 domains and flow cytometry to define the epitopes of several polymorphic anti-DR antibodies. Both DR(β 1*0403) residues 14 and 25 were shown to be involved in the epitopes of mAbs DA6. 164, HU-20, Q5/6, and 50D6, and DR(β 1*0701) residue 14 was shown to be critical for the epitopes of two DR7-specific mAbs, SFR16-DR7M and TAL 13. 1. Unlike most other residues shown to be important in antibody-binding epitopes, residue 14 is located in the floor of the peptide-binding groove and residue 25 is in an outer loop, each with their side chains pointing down, such that antibodies may directly contact these residues from below the binding groove. Two residues in the β2 domain, β180 and β181, were also shown to be involved in the epitopes of three polymorphic anti-DR mAbs, NFLD.D1, NFLD.M1, and LY9. Although these two residues are close to the transmembrane domain in the linear sequence, their solvent accessibility in the DR1 structures is quite impressive. Our data provide new evidence that residues accessible under the peptidebinding groove contribute to polymorphic antibody-binding epitopes.  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