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   1484725篇
  免费   120430篇
  国内免费   6720篇
耳鼻咽喉   18742篇
儿科学   47717篇
妇产科学   39633篇
基础医学   203272篇
口腔科学   43207篇
临床医学   131507篇
内科学   310514篇
皮肤病学   35458篇
神经病学   122672篇
特种医学   60069篇
外国民族医学   294篇
外科学   228247篇
综合类   32701篇
现状与发展   3篇
一般理论   465篇
预防医学   122268篇
眼科学   30796篇
药学   102546篇
  5篇
中国医学   2831篇
肿瘤学   78928篇
  2019年   12063篇
  2018年   17580篇
  2017年   13740篇
  2016年   15731篇
  2015年   17740篇
  2014年   24688篇
  2013年   35733篇
  2012年   45654篇
  2011年   48720篇
  2010年   29300篇
  2009年   28307篇
  2008年   43920篇
  2007年   46878篇
  2006年   47362篇
  2005年   46239篇
  2004年   44003篇
  2003年   42452篇
  2002年   38762篇
  2001年   69822篇
  2000年   71723篇
  1999年   60007篇
  1998年   18000篇
  1997年   16091篇
  1996年   17040篇
  1995年   17093篇
  1994年   15920篇
  1993年   14849篇
  1992年   49127篇
  1991年   47771篇
  1990年   45801篇
  1989年   43634篇
  1988年   40398篇
  1987年   39576篇
  1986年   37335篇
  1985年   36027篇
  1984年   27389篇
  1983年   22934篇
  1982年   14307篇
  1981年   12863篇
  1980年   12129篇
  1979年   24319篇
  1978年   17549篇
  1977年   14782篇
  1976年   13514篇
  1975年   14180篇
  1974年   16525篇
  1973年   15855篇
  1972年   14569篇
  1971年   13393篇
  1970年   12277篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
The value of maternal C-reactive protein (CRP) levels as predictors of fetal and maternal infective morbidity and fetal mortality was assessed prospectively over a 6-month period in all cases of premature rupture of the fetal membranes or suspected premature labour. Statistical analysis of results showed that CRP at a level of 1.32 mg/dl is a sensitive marker of infective morbidity in mother and neonate. Furthermore, there was a significant association between raised CRP levels and low-birth-weight babies, suggesting that intra-uterine infection is a major cause of prematurity in the study population.  相似文献   
993.
Following the outbreak of poliomyelitis in Gazankulu in 1982, the immunisation services in Gazankulu were thoroughly examined. As a result of this, a comprehensive immunisation policy for Gazankulu was accepted in November 1986. The broad aim of the policy is to provide effective immunisation to all Gazankulu residents against tuberculosis, diphtheria, pertussis, tetanus, poliomyelitis and measles. A specific objective is that by the end of 1987, 85% of under-5s should have been vaccinated against these six diseases and by the end of 1990 this percentage should be 97%. The detailed strategies to reach these objectives are highlighted. Within the framework of the objectives, the policy allows different areas to formulate individual strategies. Programme monitoring and community involvement are two crucial aspects of the policy and these are discussed in detail. The early successes and difficulities in implementing this policy are discussed.  相似文献   
994.
The second documented case of renal aspergilloma due to Aspergillusflavus is presented. The merits of the medical therapy thatfailed are discussed. Pathological examination showed a nidusof aspergillus around suture material persisting from a pyelolithotomyoperation 2 years before in India. We argue that this was thereason for the failure of the medical therapy. This is the firstcase of its kind reported.  相似文献   
995.
996.
Summary: Fifty-seven isolates of Basidiobolus from reptiles and amphibians, and 7 other obtained from the American Type Culture Collection (ATCC) in Maryland were studied for their extracellular enzyme activities on solid media. The Conidiobolus isolates studied included 4 recovered from Nigerian soil and additional 4 obtained from the ATCC All these isolates produced active extracellular lipase and protease and failed to exhibit amylase, deoxyribonuclease and ribonuclease activities. The significance of the findings is discussed.
Zusammenfassung: Fünfundsiebzig Basidiobolus-Isolate aus Reptilien und Amphibien und sieben weitere aus der American Type Culture Collection (ATCC) in Maryland wurden auf Aktivtäten extrazellulärer Enzyme auf festen Medien untersucht Die untersuchten Conidiobolus-Isolate schlossen vier aus nigerianischen Böden und vier weitere aus der ATCC ein. Alle Isolate zeigten extrazellulär Lipase- und Proteaseaktivität Amylase-, Desoxyribonuclease- und Ribonucleaseaktivität war jedoch nicht nachzuweisen. Die Bedeutung dieser Befunde wird diskutiert.  相似文献   
997.
Two hundred and thirty pregnancies were studied in 196 diabetic women. Seven women with babies found to have major malformations had a higher median first trimester haemoglobin A1 (12.9%) than the median HbA1 (10.8%) in those with normal babies (p = 0.06). No relationship was found between the occurrence of minor malformations and first trimester maternal haemoglobin A1. Two of the seven congenital malformations were diagnosed antenatally at a time when therapeutic abortion could be offered. Expert antenatal ultrasound scanning should be offered to all pregnant diabetic women as poor glycaemic control at the time of conception and organogenesis, as evidenced by raised first trimester HbA1, predisposes to congenital malformation.  相似文献   
998.
Various cases are presented demonstrating the role of computed tomography (CT) in the assessment of serosal and bowel wall pathology. Reference is made to the morphology of the lesions. Illustrative examples of tumors, secondary malignant dissemination, irradiation injury to the gut, and intramural gas associated with ulcerative colitis, are all illustrated.  相似文献   
999.
1000.
Potential digestibility and rate of degradation of water-insoluble material (WIM) prepared from rutabaga, wheat bran and digesta recovered from the terminal ileum of pigs fed bran- or rutabaga-based diets were measured in the cecum of surgically modified pigs. WIM samples recovered from the cecum after fixed incubation times were analyzed and the rate of total disappearance of organic matter, cellulose, uronic acid and noncellulosic neutral sugars was calculated. Maximum degradation of each WIM occurred within 48 h after incubation and was for rutabaga and its ileal digesta 90 and 70%, respectively, and for bran and bran ileal digesta 55 and 45%, respectively. Cellulose and uronic acid in bran samples did not appear to be degraded, material disappearance being attributable to the loss of noncellulosic neutral sugars. Estimation of potential organic matter digestibility showed rutabaga to be 93%, rutabaga digesta 79%, bran 56% and bran digesta 43% digestible. Fractional rates of digestion in rutabaga samples were significantly faster than in corresponding bran samples. When related to the role of fiber in nutrition the results obtained suggest that cereal fiber would be only slightly modified during gut transit, unlike vegetable fiber in which microbial digestion would probably result in the total destruction of the fiber cell wall matrix.  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