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   1263871篇
  免费   94817篇
  国内免费   1580篇
耳鼻咽喉   16313篇
儿科学   41001篇
妇产科学   34947篇
基础医学   189401篇
口腔科学   34732篇
临床医学   117752篇
内科学   247813篇
皮肤病学   27278篇
神经病学   101850篇
特种医学   46761篇
外国民族医学   265篇
外科学   178593篇
综合类   25749篇
现状与发展   3篇
一般理论   568篇
预防医学   104656篇
眼科学   28044篇
药学   92557篇
  7篇
中国医学   2023篇
肿瘤学   69955篇
  2018年   13530篇
  2017年   10390篇
  2016年   11323篇
  2015年   13080篇
  2014年   18003篇
  2013年   27480篇
  2012年   37577篇
  2011年   39969篇
  2010年   23058篇
  2009年   22251篇
  2008年   37753篇
  2007年   40383篇
  2006年   39965篇
  2005年   39103篇
  2004年   37545篇
  2003年   35959篇
  2002年   34868篇
  2001年   56032篇
  2000年   57044篇
  1999年   48099篇
  1998年   13396篇
  1997年   12224篇
  1996年   12645篇
  1995年   11914篇
  1994年   11107篇
  1993年   10400篇
  1992年   38198篇
  1991年   37675篇
  1990年   36449篇
  1989年   35258篇
  1988年   32690篇
  1987年   32028篇
  1986年   30526篇
  1985年   28786篇
  1984年   21941篇
  1983年   19192篇
  1982年   11364篇
  1981年   10322篇
  1979年   20944篇
  1978年   15393篇
  1977年   12790篇
  1976年   11845篇
  1975年   12810篇
  1974年   15588篇
  1973年   15362篇
  1972年   14512篇
  1971年   13552篇
  1970年   12786篇
  1969年   12065篇
  1968年   11229篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
81.
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   
82.
Nearly 13 million people die each year from cardiovascular diseasesand half of these deaths occur in developing countries. Thisarticle reviews the appropriateness of cardiovascular diseaseintervention and focuses on decision-making and the perpetualquestion: When is it more appropriate to act on available evidencerather than to await further evidence? A fundamental and justifiedprinciple in science is trying to falsify all formulated hypotheses.This sceptical or conservative approach can, however, hampersocial development. It is therefore important for the scientistto distinguish between his role as a scientist and as a memberof society. Medical, epidemiological and economic aspects areconsidered together with an assessment of the feasibility ofdifferent intervention strategies. This review, like many others,indicates that population-based interventions combined withan improved high-risk strategy are appropriate from society'spoint of view in spite of the fact that there are several unsettledquestions which call for further research.  相似文献   
83.
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   
84.
Eight-eight female weanling Sprague-Dawley rats were fed diets containing either 650 or 150 mg magnesium/kg diet and 7.0 or 3.5 mg pyridoxine-HCl/kg diet, in a 2 x 2 factorial arrangement, during growth, gestation, and lactation. The objective of the study was to determine whether concurrent dietary deficiencies of magnesium and pyridoxine were synergistic, additive, or antagonistic with regards to effects on reproductive performance, growth, and development of offspring, and tissue content of magnesium and calcium. Body weight of dams and pups was not different between groups until day 9 of lactation, at which point those animals in either low magnesium group weighed less than the other. Litter size and birth weight were not different. Development, as measured by timing of unfolding of the external ear, opening of both eyes, and clinical emergence of incisors, was delayed in pups from litters in the low magnesium groups. A synergistic effect on delay of onset of ear unfolding by deficiency of both magnesium and pyridoxine was observed. Calcium content of heart and kidney from dams was increased in the low magnesium groups. Renal calcium was not further increased by the level of pyridoxine deficiency in this study. The calcium to magnesium ratio in heart from pups was higher in those from litters in the low magnesium and pyridoxine group than in the others. Results indicate that simultaneous deficiencies of magnesium and pyridoxine may impair function synergistically. Because these two nutrients are often reported to be presented in inadequate amounts in diets of women in their reproductive years, the potential exists for impaired reproductive success.  相似文献   
85.
86.
87.
A case is presented which demonstrates the potential utility of the extracranial-intracranial bypass procedure for the treatment of vasospasm after subarachnoid hemorrhage. Extracranial-intracranial bypass surgery offers another alternative to the treatment of patients with vasospasm who have failed aggressive medical management.  相似文献   
88.
89.
The composition of the clientele from an ophthalmological practitioner's office is described with special reference to the occurrence of glaucoma and disc haemorrhages (h in singular; hh in plural). This study could not be planned as an epidemiological survey and gives no clue to sensitivity or specificity of hh in glaucoma. During a period of about 10 years ending with 1986 there were 731 patients with h and/or glaucoma. When detected, 185 patients had h but no glaucoma, 33 had both h and glaucoma and 513 had glaucoma but no h. During the follow-up period hh were detected in 83 cases of glaucoma, and glaucoma developed in 27 cases with hh. The detection rate of hh among glaucoma was low but steady, indicating that hh may occur at any stage of the glaucoma process. This study shows no predilection for hh in cases with general hypertension or diabetes, nor is the frequency of hh among pseudoexfoliation cases significantly lower than among cases without this stigma.  相似文献   
90.
Isotretinoin (Accutane Capsules) is a synthetic vitamin A compound used for treatment of recalcitrant cystic acne. It has numerous ocular toxic side effects which include anterior segment inflammation, dry eye syndrome, contact lens intolerance, altered refraction, photosensitivity, and reduced night vision. Eye care practitioners should be aware of these potential side effects and be prepared to communicate with the prescribing physician if side effects present.  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