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   165694篇
  免费   50166篇
  国内免费   6872篇
耳鼻咽喉   2200篇
儿科学   5370篇
妇产科学   1536篇
基础医学   24920篇
口腔科学   6765篇
临床医学   23969篇
内科学   34837篇
皮肤病学   8136篇
神经病学   17014篇
特种医学   5362篇
外国民族医学   49篇
外科学   22181篇
综合类   17930篇
现状与发展   29篇
一般理论   38篇
预防医学   11222篇
眼科学   3819篇
药学   15204篇
  126篇
中国医学   7338篇
肿瘤学   14687篇
  2024年   426篇
  2023年   1747篇
  2022年   4215篇
  2021年   6520篇
  2020年   8879篇
  2019年   13780篇
  2018年   13150篇
  2017年   14388篇
  2016年   14787篇
  2015年   16174篇
  2014年   16914篇
  2013年   17022篇
  2012年   11132篇
  2011年   11576篇
  2010年   13879篇
  2009年   9530篇
  2008年   6989篇
  2007年   5614篇
  2006年   5563篇
  2005年   4714篇
  2004年   3713篇
  2003年   3604篇
  2002年   3218篇
  2001年   2947篇
  2000年   2577篇
  1999年   2051篇
  1998年   1116篇
  1997年   1036篇
  1996年   825篇
  1995年   772篇
  1994年   679篇
  1993年   403篇
  1992年   498篇
  1991年   407篇
  1990年   323篇
  1989年   333篇
  1988年   285篇
  1987年   250篇
  1986年   153篇
  1985年   142篇
  1984年   79篇
  1983年   61篇
  1982年   47篇
  1981年   41篇
  1980年   26篇
  1979年   41篇
  1978年   21篇
  1975年   13篇
  1974年   13篇
  1970年   7篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
乡(镇)卫生院是农村三级医疗预防保健网的中心环节,是我国农村实现“2000年人人享有卫生保健”的关键。本文通过对广东省梅县乡(镇)一级卫生院卫生人力状况的调查分析,结果表明,目前该县乡镇卫生院的机构稳定,卫技人员占编比例合理,年龄较轻,成为今后农村卫生院发展的优势。但存在着卫生技术人员的总体数量不足,素质较差,各类专业技术人员的构成比例失调和层次分布不合理等问题,同时提出了如何加以改善的对策措施。  相似文献   
92.
大气中不同粒径颗粒物诱导人羊膜FL细胞UDS的研究   总被引:3,自引:0,他引:3  
本研究以诱导人羊膜细胞UDS为指标,对太原市大气不同粒径的颗粒物提取液进行了致突变性检验,结果表明,不同粒径颗粒物的提取液均可产生一定的遗传毒性,尤以3.3μm以下的颗粒物的遗传毒性较强。  相似文献   
93.
1. In membranes prepared from a permanent cell line of endothelial origin (WEC cells), [3H]-alpha, beta-methylene ATP ([3H]-alpha, beta-meATP) labelled high (pKd = 9.5; Bmax = 3.75 pmol mg-1 protein) and low (pKd = 7.2; Bmax = 23.3 pmol mg-1 protein) affinity binding sites. The high affinity [3H]-alpha, beta-meATP binding sites in the WEC cell membranes could be selectively labelled with a low concentration of the radioligand (1 nM). In competition studies performed at a radioligand concentration of 1 nM, 88.6% of the sites possessed high affinity (pIC50 = 8.26) for alpha, beta-meATP. 2. The high affinity [3H]-alpha, beta-meATP binding sites appeared heterogeneous since in competition studies a number of nucleotide analogues (alpha, beta-meADP, ATP, ADP, AMP, GTP, GppNHp, GMP) and adenosine identified two populations of the sites labelled by 1 nM [3H]-alpha, beta-meATP. The proportion of sites with high affinity for these compounds was found to vary between 42 and 69%. 3. Approximately 60-69% of the binding sites labelled with 1 nM [3H]-alpha, beta-meATP possessed high affinity for alpha, beta-meADP (pIC50 = 8.87), AMP (pIC50 = 7.12), GMP (pIC50 = 7.34), UTP (pIC50 = 6.12), GTP (pIC50 = 7.59), GppNHp (pIC50 = 7.35) and adenosine (pIC50 = 5.45).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
94.
Y Q Li  W Yuan  S L Zhang 《中国中西医结合杂志》1992,12(12):719-21, 737, 708
Xiao Er Ke Chuan Ling Oral Liquid (KCL) is a Chinese herbal preparation consisted of 10 herbs such as Prunus armeniacae, Scutelaria baicalensis, Lonicera japonica etc. 30 children suffering from bronchopneumonia and/or acute bronchitis were treated with KCL (treated group) and another 30 cases were treated with penicillin and aminophylline (control group). Results: cure rate and effective rate in treated group was 26.6%, and 93.3% respectively. While in control group was 30% and 96.6% respectively. No significant differences were seen between them(P > 0.05). The pharmacodynamic experiment showed KCL had potent pharmacological action. The experiment on tracheal fragment of Guinea pig in vitro showed it caused moderately strong smooth muscle relaxation, through inhibition the effect of histamine and acetylcholine. Asthma induction experiment of Guinea pig in vivo showed KCL could significantly prolong the latent period of asthma and alleviate asthmatic symptom. Ammonium water cough induction experiment in mice showed it may apparently prolong cough latent period and reduce times of cough relapse and alleviate cough symptom. KCL had potent antipyretic effect on fever model induced by triple vaccine in rabbits. Bacteriostatic and antiviral experiment in vitro showed the drug had quite strong inhibitory effects for Streptococcus hemolyticus, Staphylococcus aureus, Flexners Dysentery bacillus, Diplococcus pneumoniae and Pseudomonas aeruginosa, and it could potently inhibit the respiratory syncytial virus. KCL is an effective drug in treating bronchopneumonia and acute bronchitis.  相似文献   
95.
本文采用层析法进行鉴定,用氨基酸分析仪测氨基酸的含量,为胎盘组织液的质量标准提供可靠依据。本法准确率为99%。  相似文献   
96.
97.
Objective. To study the characteristics of changes of LDH enzyme patterns of mice under slight hypoxia.Methods. Mice treated with artificial hypoxia, various tissues were made for the test of LDH enzymatic activity by the specific staining technique. LDH (1 -5) relative percentage enzymatic activity (RPEA) were measured with CS-910 dual-wavelength thin layer chromatography scanner.Results. The RPEA of LDH isozymes of various tissues after slight hypoxia shifted to the isozymes LDH1 and LDH2, whose principal subunits are H subunits, and the RPEA of LDH,(H4), LDH2(H3M) increased, while RPEA of LDH5(M4) in various tissues decreased prominently except the cardiac muscle, and that of LDH4(HM3) decreased as well. After polyacrylamide gel electrophoresis (PAGE) of the hypoxia treated cardiac muscle specimen was made, activity subbands originated regularly in the isozyme patterns of LDH, with the regularity of LDH1 (0 subband), LDH2 (0-1 subbands), LDH3 (0-2 subbands), LDH4 (1-3 subbands), LDH5 (2-4 subbands).  相似文献   
98.
XIAP与肿瘤化疗耐药关系的研究进展   总被引:1,自引:0,他引:1  
细胞凋亡程度的降低是肿瘤发生的主要机理,造成肿瘤对化疗药物耐药的主要原因是化疗药物介导的细胞凋亡指数的下降。凋亡抑制蛋白在抑制细胞凋亡中起非常重要的作用,XIAP是IAP家族中抑制细胞凋亡的最主要成员。本文总结了近年来对XIAP抗凋亡机制的研究及其在肿瘤化疗耐药方面的作用。  相似文献   
99.
MHC—I类抗原加工途径异常与肿瘤关系的研究进展   总被引:1,自引:0,他引:1  
杨文武 《中国肿瘤》2003,12(3):160-163
随着免疫学研究的不断深入,MHC-I类抗原呈递细节已逐渐明晰,全面认识肿瘤细胞MHC-I类相关抗原加工途径缺陷或改变与肿瘤生物学及肿瘤临床的关系,将有助于肿瘤的诊治和预防。  相似文献   
100.
OBJECTIVE: To study the value of serum progesterone in selecting the candidate patients with ectopic pregnancy (EP) for methotrexate (MTX) treatment and in monitoring the effect of the treatment. METHODS: Thirty-seven EP patients who were given single-dose intramuscular injection with 50 mg/m2 MTX were divided into success and failure groups according to the effect of the treatment. The serum progesterone concentrations in these patients were measured and compared between the 2 groups, and the receiver-operator curves (ROC) were used to determine the critical serum progesterone levels for assessing the effect of MTX treatment. The time consumed respectively by serum progesterone and beta-human chorionic gonadotrophin (beta-hCG) decreasing to below normal level was also compared. RESULTS: The serum progesterone concentrations of the success group (7.93+/-2.02 ng/ml) were significantly lower than those of the failure group (14.53+/-1.72 ng/ml, P<0.05). The recommended critical level for assessing the effect of MTX treatment for EP patients was 11 ng/ml according to the ROC, and the time for serum progesterone decreasing to below normal level was significantly less than that for beta-hCG. CONCLUSION: Serum progesterone can be used as an index for selecting candidate EP patients for MTX treatment, and also as a good indicator for assessing the therapeutic effect after treatment.  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