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   3488104篇
  免费   282798篇
  国内免费   14593篇
耳鼻咽喉   48462篇
儿科学   106933篇
妇产科学   91282篇
基础医学   546979篇
口腔科学   96880篇
临床医学   308370篇
内科学   618217篇
皮肤病学   93045篇
神经病学   297935篇
特种医学   138869篇
外国民族医学   453篇
外科学   543370篇
综合类   107087篇
现状与发展   24篇
一般理论   2262篇
预防医学   284315篇
眼科学   79626篇
药学   242983篇
  23篇
中国医学   10347篇
肿瘤学   168033篇
  2021年   54914篇
  2020年   35040篇
  2019年   58025篇
  2018年   70835篇
  2017年   54089篇
  2016年   59844篇
  2015年   73981篇
  2014年   108169篇
  2013年   173358篇
  2012年   90088篇
  2011年   89158篇
  2010年   115510篇
  2009年   120724篇
  2008年   77092篇
  2007年   80620篇
  2006年   91464篇
  2005年   86784篇
  2004年   89024篇
  2003年   80385篇
  2002年   70698篇
  2001年   109274篇
  2000年   102388篇
  1999年   101323篇
  1998年   65231篇
  1997年   63132篇
  1996年   60647篇
  1995年   56092篇
  1994年   50324篇
  1993年   47019篇
  1992年   71714篇
  1991年   68015篇
  1990年   64993篇
  1989年   64335篇
  1988年   60216篇
  1987年   58840篇
  1986年   56328篇
  1985年   55964篇
  1984年   50483篇
  1983年   45770篇
  1982年   42318篇
  1981年   39785篇
  1980年   37627篇
  1979年   42935篇
  1978年   37352篇
  1977年   34266篇
  1976年   31033篇
  1975年   30688篇
  1974年   32403篇
  1973年   31074篇
  1972年   29501篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Thirty-nine primary surgical cases for correction of congenital aural atresia were reviewed for complications and long-term hearing results. Hearing averages of 25 dB for mild atresia, 40 dB for moderate atresia, and 46 dB for severe atresia were obtained. Serviceable hearing was achieved in 64% of the cases. The two most frequent complications were stenosis and recurrent infections of the cavity and canal skin, with an incidence of 33% and 31%, respectively. Use of split-thickness instead of full-thickness skin graft was associated with fewer complications. The goal of this review is also to share the experience of the senior author in the management of this complex problem.  相似文献   
993.
The decoction of Sclerocarya birroea Hochst. shows hypoglycaemic effects, an increase in plasma IRI in normal rats and an incremented oral-glucose tolerance. The decoction is also active against diet-induced hypercholesterolaemia.  相似文献   
994.
Development of an auxotrophic oral live Shigella flexneri vaccine   总被引:11,自引:0,他引:11  
An oral live attenuated Shigella flexneri vaccine candidate strain was constructed by making it auxotrophic and dependent on aromatic metabolites not available in mammalian tissues. An aroD gene of Escherichia coli K12 strain NK 5131, inactivated by insertion in it of the Tn 10 transposon, was transduced using phage P1 into a virulent S. flexneri serotype Y strain (Sfl 1) isolated from a patient with bacillary dysentery. One of the transductant strains Sfl 114 was found to invade HeLa cells in vitro, to cause plaque formation in HeLa monolayers (i.e. maintain intracellular multiplication in vitro), but to be unable to cause keratoconjunctivitis in guinea-pig eyes. When the strain was fed to Macacca fascicularis monkeys it was well tolerated, excreted for 1-4 days, and found to elicit a local intestinal sIgA and serum IgA, IgM and IgG responses. Monkeys challenged with 100 ID50 dose (1 X 10(11) bacteria) of the virulent parent Sfl 1 strain were completely protected from development of diarrhoea. Coloscopy of the monkeys and the sampling of intestinal biopsies showed that the vaccine protected against the surface epithelial erosions and ulcerations seen in unimmunized monkeys. Killing of invading virulent shigellae apparently took place intracellularly in the mucosa suggesting that cellular immune mechanisms played a role in the elicited host defence. The constructed S. flexneri Sfl 114 strain has the properties of a promising shigella vaccine and will next be the subject of studies with human volunteers.  相似文献   
995.
This study surveyed male and female athletes from 22 midwesterncolleges and universities regarding behaviors and attitudesassociated with anorexia nervosa and bulimia nervosa. The responserate was 66% (N= 695) and the findings indicated that the bodyimage of some athletes may be distorted; one-seventh perceivedthemselves as fat even though they were not. Many athletes seemedpreoccupied with food and weight; almost one-third reportedroutinely thinking about food and weight and more than one-thirdreported dramatic annual weight fluctuations (9 lb or greater)related to bingeing and fasting. Athletes also did not feelin control when they ate and their habits related to food consumptionappeared to be extreme; one-tenth reported a lack of controlwhen they ate, more than one-third binged, one-twentieth ateuntil they were physically ill, and a similar proportion preferrednot to eat in the presence of others. In addition, it was foundthat as many men as women athletes reported these perceptionsbut significant sex differences were noted for specific items.It was suggested that behaviors and attitudes be viewed on acontinuum with normals at one end, eating disordered individuals at the other end,and college athletes in between. Health education that focuseson behaviors and attitudes as symptoms of eating disorders wasrecommended for athletes and those working closely with athletes.Future research was suggested to determine reasons for the undesirablebehaviors and attitudes and to study the onset, development,long-term effects and whether these behaviors and attitudeslead to an eating disorder.  相似文献   
996.
To study the effect of alcohol on glucose and insulin metabolism,a simultaneous infusion of glucose and insulin was given for150 min to healthy volunteers, once during alcohol and onceduring calorie-free gingerale (control) ingestion. During alcoholintake, the average steady-state (between 100 and 150 min) glucoseof 5.44±0.39 mmol/1. and the average steady-state insulinof 6.3±1.1 ng/ml were significantly higher than those(4.0±0.39 mmol/1. of glucose and 4.4±0.6 ng/mlof insulin) observed during the control state. Despite the highersteady-state insulin concentrations, the glucose metabolismwas significantly less during alcohol ingestion. These findingssuggest alcohol-induced impairment in glucose metabolism iscaused by a decreased tissue sensitivity to insulin.  相似文献   
997.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.  相似文献   
998.
One of our patients had trouble maintaining therapeutic and safe levels of theophylline, even though we were careful in planning and monitoring her drug regimen. This case report shows how we were able to use principles of pharmacokinetics to distinguish among plausible explanations for her experience. We discovered that she was not taking the drug consistently as prescribed and that supervised administration resolved apparent contradictions between doses and serum levels. We believe that physicians can use the same information and methods that we used to get better and safer results from theophylline therapy.  相似文献   
999.
1000.
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