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   42291篇
  免费   3326篇
  国内免费   1096篇
耳鼻咽喉   462篇
儿科学   966篇
妇产科学   910篇
基础医学   5745篇
口腔科学   1289篇
临床医学   3662篇
内科学   8170篇
皮肤病学   787篇
神经病学   3194篇
特种医学   1544篇
外国民族医学   2篇
外科学   6342篇
综合类   2750篇
现状与发展   1篇
一般理论   20篇
预防医学   2578篇
眼科学   934篇
药学   3801篇
中国医学   467篇
肿瘤学   3089篇
  2023年   222篇
  2022年   573篇
  2021年   957篇
  2020年   551篇
  2019年   761篇
  2018年   1128篇
  2017年   804篇
  2016年   898篇
  2015年   990篇
  2014年   1274篇
  2013年   1653篇
  2012年   2248篇
  2011年   2200篇
  2010年   1336篇
  2009年   1097篇
  2008年   1818篇
  2007年   1986篇
  2006年   1816篇
  2005年   1544篇
  2004年   1380篇
  2003年   1227篇
  2002年   1081篇
  2001年   2413篇
  2000年   2304篇
  1999年   1911篇
  1998年   739篇
  1997年   505篇
  1996年   359篇
  1995年   311篇
  1994年   282篇
  1993年   249篇
  1992年   1087篇
  1991年   941篇
  1990年   862篇
  1989年   941篇
  1988年   843篇
  1987年   783篇
  1986年   714篇
  1985年   649篇
  1984年   411篇
  1983年   355篇
  1982年   201篇
  1981年   148篇
  1980年   136篇
  1979年   234篇
  1977年   107篇
  1974年   117篇
  1973年   125篇
  1972年   115篇
  1971年   103篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
用AR CM MIC阳离子测定系统,测量单个细胞内游离钙浓度([Ca2+]i),研究8-(N,N-二乙胺)-n-辛基 3,4,5-三甲氧基苯甲酸酯(TMB-8)对培养乳牛基底动脉平滑肌[Ca2+]i的作用。在细胞外钙浓度为1.3mmol·L-1时,TMB-8(30μmol·L-1)可明显抑制BHQ,NE及KCl引起[Ca2+]i的升高。在细胞外钙为零+EGTA 0.1mmol·L-1时,TMB-8(10,30及100μmol·L-1)可浓度依赖性地降低静息[Ca2+]i,TMB-8(30μmol·L-1)可几乎完全阻断BHQ及NE引起[Ca2+]i的增加。研究表明TMB-8降低培养乳牛基底动脉平滑肌[Ca2+]i的机制,主要是抑制肌浆网Ca2+的释放,或增加肌浆网对Ca2+的摄入,并由此间接地抑制细胞外钙的内流。  相似文献   
32.
A novel cardiokymograph system is introduced. The new system features a capacitance transducer with increased sensitivity and can be used in multichannel measurements. The novelty of this technique is the injection of a current into the patient coupled with the use of a capacitive displacement transducer and the possibility of multichannel monitoring. It provides for the possibility of removing breath noise when some signal processing technique, such as adaptive filtering, is used. Further investigation is needed to demonstrate clinical significance and pathologies.  相似文献   
33.
34.
Five commercially available nitropolyclyclic aromatic hydrocarbons (nitro-PAH), namely, 4-nitrobiphenyl, 2-nitrofluorene, 9-nitroanthracene, 1-nitropyrene, and 2,7-dinitrofluorene, were exposed under restricted sunlight in the open air. The direct-acting mutagenicities of the samples after an exposure of 45 days were measured in order to compare them with those of the original samples in the Ames Salmonella typhimurium bioassay. It was found that the mutagenicities of some nitro-PAH do not change significantly while the mutagenicities of others increase or decrease after exposure. A preliminary study of nitro-PAH reaction products after exposure using GC, GC/MS, and FT-IR is also reported.  相似文献   
35.
Reabsorptive action of collagen fibers of the liver   总被引:35,自引:0,他引:35  
  相似文献   
36.
37.
38.
The hereditary characteristics of enzyme deficiency and dermatoglyphics in congenital color blindness (CCB) were studied. We propose that there is a linkage between the two loci on the X-chromosome determining CCB and glucose-6-phosphate dehydrogenase (G6PD), based on our study of a high incidence of G6PD deficiency in 156 male cases with CCB. The CCB gene is closely linked with that of G6PD deficiency from our pedigree investigations. The rise in the frequency of eight or more whorls, the low value of atd angle and the presenting rate of real palmar patterns of the thenar, hypothenar and I, areas presented the hereditary traits of congenital color blindness.  相似文献   
39.
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   
40.
Y R Zhao  D F Zhang  C Q Pan 《中华内科杂志》1992,31(11):686-8, 730
Viral markers were studied in 79 cases of viral hepatitis with hepatic failure. The results were shown as follows: 8 cases were positive for anti-HAV IgM (10.12%); 76 cases positive for HBsAg or anti-HBc IgM (96.20%) and 41 cases positive for anti-HCV antibodies (51.89%). Among those with anti-HCV positive, 35 cases were co-infected with HBV, 5 cases with HAV and/or HCV, only one was infected with HCV alone 2 cases were HD-Ag positive (2.52%) and one not identified (1.27%). With the reference of clinical findings, patients co-infected with HBV/HCV or anti-HBc IgM positive were more critical and usually entail higher mortality. In cases with HCV co-infections, the positive HBV replication markers seems to be reduced. Hepatic failure without HBV replicative markers had a high rate of hepatic coma as well as poor outcome.  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