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   2355725篇
  免费   171917篇
  国内免费   3347篇
耳鼻咽喉   32208篇
儿科学   75947篇
妇产科学   62719篇
基础医学   349043篇
口腔科学   63793篇
临床医学   211669篇
内科学   458613篇
皮肤病学   51874篇
神经病学   185686篇
特种医学   88174篇
外国民族医学   489篇
外科学   355236篇
综合类   47525篇
现状与发展   12篇
一般理论   849篇
预防医学   182869篇
眼科学   54356篇
药学   175538篇
  11篇
中国医学   4583篇
肿瘤学   129795篇
  2021年   19098篇
  2019年   19600篇
  2018年   27143篇
  2017年   20433篇
  2016年   22841篇
  2015年   25726篇
  2014年   36194篇
  2013年   54073篇
  2012年   74904篇
  2011年   79642篇
  2010年   47199篇
  2009年   44692篇
  2008年   74830篇
  2007年   79717篇
  2006年   80519篇
  2005年   78028篇
  2004年   74634篇
  2003年   71946篇
  2002年   69620篇
  2001年   108960篇
  2000年   111672篇
  1999年   93734篇
  1998年   27079篇
  1997年   23732篇
  1996年   24127篇
  1995年   22770篇
  1994年   20951篇
  1993年   19765篇
  1992年   72134篇
  1991年   70160篇
  1990年   68511篇
  1989年   65807篇
  1988年   60426篇
  1987年   59261篇
  1986年   55342篇
  1985年   53127篇
  1984年   39383篇
  1983年   33466篇
  1982年   19893篇
  1979年   35947篇
  1978年   25703篇
  1977年   21275篇
  1976年   20363篇
  1975年   21863篇
  1974年   26182篇
  1973年   24834篇
  1972年   23243篇
  1971年   22074篇
  1970年   20278篇
  1969年   19353篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Clinical and biological data were evaluated using Desu univariate analyses or Cox multivariate analyses in a series of 1,777 chronic lymphocytic leukemia (CLL) patients from an Italian Cooperative Group. In univariate analyses, age and sex of patients, presence of bone marrow (BM; greater than or equal to 50%), and peripheral blood (PB; greater than or equal to 60,000/microL) lymphocytosis, anemia (hemoglobin [Hb] less than 11 g/dL), thrombocytopenia (less than 100,000/microL), direct Coombs' test positivity, hepatomegaly, splenomegaly, and extent of lymph node involvement were shown to be of significant prognostic value. Multivariate analyses, through a stepwise procedure, showed that the most important prognostic variables are Hb, hepatomegaly, lymph node involvement, PB lymphocytosis, and age and sex of patients. Further covariates would produce an improvement having a nonsignificant P value. Based on the results of multivariate analyses, a four-step staging using the significant variables of the Cox model is proposed.  相似文献   
992.
Synthesis of 2-(Hydrazinocarbonylthio)-acetic Acids and Cyclization to 3-Aminothiazolidine-2,4-diones N-mono- or N,N-disubstituted hydrazines are reacted with carbonyl sulfide, triethylamine and halogenoacetic acids to yield the 2-(hydrazinocarbonylthio) acetic acids 1 , which are cyclizised to yield the 3-aminothiazolidine-2,4-diones 2 by dicyclohexylcarbodiimide.  相似文献   
993.
Several reports in the literature suggest a relationship between lead intoxication and thermoregulatory capacity. To investigate the effects of lead on the control of body temperature, mice of the BALB/c strain were injected intraperitoneally with lead acetate (0 to 100 mg/kg) while colonic temperature was measured 30, 60, and 90 min post-injection at ambient temperatures (Ta) of 20 and 30 degrees C. Lead acetate caused a transient hypothermia, an effect which was augmented at cooler Ta's. In a second experiment, mice were injected with 100 mg/kg lead acetate and placed in a longitudinal temperature gradient to measure their preferred Ta. Lead acetate significantly reduced the preferred Ta during the first 30 min post-injection which augmented the lead-induced hypothermia. In a third experiment it was found that lead acetate-induced lethality was potentiated with increasing Ta. Hence, the hypothermic response to acute lead acetate treatment may be beneficial to survival.  相似文献   
994.
A case of Goldenhar’s Syndrome in a 10 year old girl is reported. The unusual features are the absence of epibulbar dermoid which is one of the major hallmarks of the Syndrome and the presence of an associated Cyanotic Heart disease.  相似文献   
995.
996.
997.
A human factors engineering analysis of a chemical containment laboratory was performed to develop appropriate standards for future laboratory design. In order to perform this evaluation, a state-of-the-art facility was studied in depth. Measurements and observations were made of key operating areas. In addition, technicians were observed and interviewed as they performed various tasks. Compiled data were compared to existing ergonomic standards. The occupational implications of instituting ergonomically developed laboratory design standards are as follows: increased worker health, safety and productivity, improved work quality and reduced stress.  相似文献   
998.
999.
The growth of microorganisms in total parenteral nutrition admixtures   总被引:1,自引:0,他引:1  
Total nutrient admixtures (TNAs) containing glucose, amino acids, and lipid emulsion in one container and amino acid/dextrose solutions [conventional total parenteral nutrition (TPN) formulations] were studied in a controlled laboratory experiment for their ability to support the growth of microorganisms. Both TNA and conventional TPN formulations for peripheral and central venous administration with standard additives were inoculated with microorganisms to provide 10(1)-10(2) colony-forming units/ml (CFU/ml) of Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans. The admixtures were stored at room temperature and samples for quantitative microbiology were taken at time 0, 6, 12, 24, 48, 72, and 96 hr. K. pneumoniae, E. coli, and P. aeruginosa were able to proliferate in central TNAs, but the growth of these organisms was retarded in conventional TPN solutions. In the peripheral formulations, K. pneumoniae and E. coli proliferated in both the TNA and conventional TPN systems, whereas P. aeruginosa grew well only in the peripheral TNA. S. epidermidis was not able to grow in any admixtures tested; however, C. albicans grew well in all admixtures, but growth was slower in the conventional central TPN. In conclusion, peripheral and central TNAs supported the growth of microorganisms significantly better than conventional TPN solutions.  相似文献   
1000.
A 43-year-old alcoholic presented in coma with ketoacidosis, after three days of nausea and feeling generally unwell, which had been preceded by a prolonged three-week period of heavy alcohol consumption with poor dietary intake. The acidosis responded rapidly to intravenous dextrose. This is the first Scottish report of a case of alcoholic ketoacidosis.  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