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   1578936篇
  免费   125620篇
  国内免费   6569篇
耳鼻咽喉   20292篇
儿科学   51608篇
妇产科学   44265篇
基础医学   220187篇
口腔科学   42617篇
临床医学   140530篇
内科学   321989篇
皮肤病学   37238篇
神经病学   127462篇
特种医学   64972篇
外国民族医学   313篇
外科学   248144篇
综合类   37612篇
现状与发展   3篇
一般理论   561篇
预防医学   123073篇
眼科学   34094篇
药学   111126篇
  5篇
中国医学   2886篇
肿瘤学   82148篇
  2018年   16274篇
  2017年   12732篇
  2016年   15182篇
  2015年   17070篇
  2014年   23585篇
  2013年   35569篇
  2012年   43414篇
  2011年   46405篇
  2010年   29314篇
  2009年   28380篇
  2008年   43323篇
  2007年   46511篇
  2006年   47453篇
  2005年   45712篇
  2004年   43751篇
  2003年   42461篇
  2002年   40216篇
  2001年   76259篇
  2000年   78433篇
  1999年   65471篇
  1998年   19111篇
  1997年   17266篇
  1996年   18068篇
  1995年   18153篇
  1994年   16910篇
  1993年   15831篇
  1992年   53647篇
  1991年   52475篇
  1990年   50580篇
  1989年   48383篇
  1988年   44613篇
  1987年   43782篇
  1986年   41302篇
  1985年   39903篇
  1984年   30203篇
  1983年   25458篇
  1982年   15875篇
  1981年   14131篇
  1980年   13339篇
  1979年   27254篇
  1978年   19755篇
  1977年   16685篇
  1976年   15225篇
  1975年   16096篇
  1974年   18922篇
  1973年   18250篇
  1972年   16844篇
  1971年   15548篇
  1970年   14349篇
  1969年   13318篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.  相似文献   
992.
The effect of apomorphine on regional cerebral blood flow in schizophrenia   总被引:1,自引:0,他引:1  
A double-blind, placebo-controlled crossover study of the effects of apomorphine on regional cerebral blood flow (rCBF) during a prefrontal cortex activation task was undertaken to explore the role of dopamine on cortical function. The subjects were eight drug-free, chronically psychotic patients; six patients had schizophrenia. In each, apomorphine increased the relative prefrontal flow. The results suggest that enhanced prefrontal dopamine activity may reverse deficits in prefrontal cortex metabolism in schizophrenia.  相似文献   
993.
994.
995.
D R Garris 《Brain research》1989,501(1):162-170
The influence of the obese (ob/ob) and diabetes (db/db) genetic mutations on hypothalamic structure was investigated in C57BL/KsJ and C57BL/6J mice strains by morphometric analysis of medial basal nuclei which are recognized to possess glucoregulatory neurons. Brains were collected and prepared for histomorphometric analysis at selected times following the development of expressed obesity and diabetes (Type II, non-insulin dependent) syndromes in order to compare both the strain and genomic influences on neuronal viability in the hypothalamic ventromedial (VMH) and arcuate (ARC) nuclei of mutant and age-matched control mice. The severity of each syndrome was determined by monitoring the concomitant changes in body weight and blood glucose levels in all groups. Both (db/db) and (ob/ob) mutant C57BL/KsJ mice exhibited an increase in the number and distribution of degenerated neurons in the VMH and ARC nuclei relative to corresponding controls. The mutation-associated exacerbation of the normal age-related neuronal loss, as observed in control MBH nuclei, was temporally associated with the overt expression of the hyperglycemic component of the obese and diabetes syndromes in aging C57BL/KsJ mice. No temporal or causal relationships were noted between the enhanced rate of premature neuronal degeneration, and either body weight or blood glucose levels, in either (db/db) or (ob/ob) C57BL/6J mice relative to controls. These data suggest that the hyperglycemic condition which characterizes the (ob/ob) and (db/db) mutant C57BL/KsJ mice is causally associated with the pronounced, premature MBH neuronal degeneration in these mouse strains. Neuronal changes were not pronounced when the genetic mutations were expressed in C57BL/6J mice. The accompanying alterations in brain glucose metabolism, hormone sensitivity, bioamine content and function which are recognized to occur in these mutant C57BL/KsJ mice may be causally associated consequences of the observed changes in MBH structural integrity and neuronal competence, with the severity of the mutation-associated changes being related to genetic background of the murine strain.  相似文献   
996.
997.
Dawn and dusk simulation as a therapeutic intervention   总被引:1,自引:0,他引:1  
  相似文献   
998.
999.
1000.
Quantitative autoradiographic analysis was used to identify regions in the brain of the male primate where androgen binding sites may be involved in the actions of testosterone. Three days after castration, adult male rhesus monkeys received a subcutaneous injection of either dihydrotestosterone propionate (DHTP, 20 mg, n = 6), testosterone propionate (TP, 100 mg, n = 2), or oil vehicle (control males, n = 4). Three hours later, 5 mCi [3H]testosterone was administered as an i.v. bolus. At 60 min, brains were rapidly removed and the left halves were used for autoradiography. In control males, highest percentages of labeled neurons (20-84% using a rigorous Poisson criterion) were observed in the ventromedial, arcuate and premammillary nuclei (n.) of the hypothalamus, medial preoptic n., bed n. of stria terminalis, intercalated mammillary n., lateral septal n. and the medial, cortical and accessory basal n. of the amygdala. Pretreatment with DHTP eliminated labeling in androgen target tissues of the genital tract, and reduced the percentages of labeled neurons to 4-22% of control values in the arcuate, lateral septal, premammillary and intercalated mammillary n., indicating that in these regions testosterone acted predominantly at androgen binding sites. However, in the medial preoptic n., the ventromedial hypothalamic n. and the accessory basal amygdaloid n., DHTP pretreatment resulted in much less blocking which, together with other data, suggested that in these sites, testosterone's actions involved aromatization and interaction with estrogen-binding sites.  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