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   28630篇
  免费   2382篇
  国内免费   133篇
耳鼻咽喉   346篇
儿科学   1037篇
妇产科学   676篇
基础医学   3452篇
口腔科学   595篇
临床医学   3739篇
内科学   5283篇
皮肤病学   436篇
神经病学   2775篇
特种医学   1062篇
外科学   3597篇
综合类   683篇
一般理论   46篇
预防医学   3158篇
眼科学   506篇
药学   2168篇
  2篇
中国医学   34篇
肿瘤学   1550篇
  2021年   400篇
  2020年   235篇
  2019年   349篇
  2018年   420篇
  2017年   303篇
  2016年   364篇
  2015年   414篇
  2014年   617篇
  2013年   937篇
  2012年   1175篇
  2011年   1332篇
  2010年   758篇
  2009年   561篇
  2008年   1159篇
  2007年   1330篇
  2006年   1274篇
  2005年   1210篇
  2004年   1192篇
  2003年   1031篇
  2002年   976篇
  2001年   966篇
  2000年   985篇
  1999年   776篇
  1998年   322篇
  1997年   298篇
  1996年   264篇
  1995年   249篇
  1994年   227篇
  1992年   695篇
  1991年   706篇
  1990年   665篇
  1989年   613篇
  1988年   606篇
  1987年   561篇
  1986年   570篇
  1985年   543篇
  1984年   426篇
  1983年   417篇
  1982年   270篇
  1981年   254篇
  1980年   229篇
  1979年   423篇
  1978年   309篇
  1977年   269篇
  1976年   245篇
  1975年   231篇
  1974年   300篇
  1973年   261篇
  1972年   233篇
  1971年   227篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
21.
1. The plasma concentrations of unconjugated phenylacetic acid and m-hydroxyphenylacetic acid are lower in male than in female subjects. 2. The plasma concentrations of unconjugated phenylacetic acid and mandelic acid decrease with increasing weight and height for all subjects combined. The same relationships apply for both males and females but are significant only for males. 3. Homovanillic and vanillylmandelic acid concentrations in plasma increase with age. 4. The importance of using age, sex, weight and height matched groups in studies involving the plasma concentrations of some of the trace amine metabolites in psychiatric disorders has been demonstrated. This is particularly the case for phenylacetic acid, the major metabolite of phenylethylamine which is now thought to be a neuromodulator of catecholaminergic neurotransmission.  相似文献   
22.
23.
24.
Designed to help persons with schizophrenia to persist and perform better at job placements, the Indianapolis Vocational Intervention Program (IVIP) is a program of cognitive-behavioral group and individual interventions. While its feasibility has been previously demonstrated, it is unknown whether IVIP assists persons to achieve greater levels of participation in vocational rehabilitation and higher levels of job performance. In this study, 100 participants with schizophrenia or schizoaffective disorder were offered a six month job placement and randomized to receive IVIP (n = 50) or support services (n = 50) matched for treatment intensity. Number of hours worked was recorded weekly and job performance was assessed biweekly using the Work Behavior Inventory with raters blind to condition. t-tests revealed that participants in the IVIP group worked a significantly greater number of weeks than those in the support condition. Also, repeated measures ANOVA revealed the IVIP group worked more hours across that 26 week period as well. And with regards to work performance, repeated measures of the 56 participants who worked for at least two-thirds of the intervention revealed that participants in the IVIP group had generally better work performance than those in the support condition. Results suggest a connection between cognitive-behavioral interventions and higher levels of work performance in people with schizophrenia.  相似文献   
25.
Serum lipoproteins, body composition, and adipose cholesterol contents of six obese women were studied during and after major weight loss by very-low-calorie diets (VLCDs). Subjects started at 168 +/- 11% of ideal body weight, lost 30.3 +/- 3.7 kg in 5-7 mo, followed by 2+ mo in weight maintenance. Serum cholesterol fell from a prediet (baseline) value of 5.49 +/- 0.32 to 3.62 +/- 0.31 mmol/L (P less than 0.01) after 1-2 mo of VLCDs (nadir), after which it rose to 5.95 +/- 0.36 mmol/L (peak, P less than 0.01 compared with nadir and baseline) as weight loss continued. With weight maintenance, serum cholesterol fell to 4.92 +/- 0.34 mmol/L (P less than 0.05 compared with peak). Adipose cholesterol content did not change in peripheral (arm and leg) biopsy sites but rose significantly in abdominal adipose tissue with weight loss. We conclude that major weight loss was associated with a late rise in serum cholesterol, possibly from mobilization of adipose cholesterol stores, which resolved when weight loss ceased.  相似文献   
26.
Patterns of exposure to distinct types of life stressors were compared between 134 children attending a military child psychiatric clinic and a matched military community control sample. Compared with the community sample, clinic-referred children had experienced significantly higher levels of normative stressful events as well as events confounded with their own adjustment and events related to parental psychosocial functioning. Differences in levels of normative stressful events were no longer significant, however, when controlling for events related to parental functioning. Ratings of stressful events during the past year significantly underestimated the lifetime stress exposure differences between clinic and community control children. Although normative stressful events, parent-related events, and parent symptomatology ratings were significantly related to child behavior problem ratings, normative stressful events did not contribute to predictions of child behavior problems beyond the variance attributable to parent-related events and parent symptomatology. Implications of these findings for life stress and child maladjustment research are discussed.  相似文献   
27.
The Levine-Pilowsky depression questionnaire was used to compare the qualitative and quantitative characteristics of depression in 176 patients admitted to a general hospital following a suicide attempt and 65 psychiatric inpatients with a diagnosis of major affective disorder. The study showed that despite significant age and sex differences there was a striking similarity between the groups on all measures of depression. Diagnostic and therapeutic implications of these findings are discussed, and further research directions are suggested.  相似文献   
28.
N S Davis 《The Prostate》1987,11(4):353-360
The finding of significant numbers of endocrine-paracrine (EP) cells in the prostate glands of guinea pigs and man suggests that these cells may be important in the regulation or modulation of prostatic function. Serotonin is a biogenic amine common to most prostatic EP cells. In order to extend current knowledge relating to these cells, an assay was developed using high-performance liquid chromatography to quantitate serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in guinea pig and human prostatic tissue extracts. Levels of serotonin and 5-HIAA in the guinea pig whole-gland preparation were 105.4 +/- 70.6 ng/g and 48.4 +/- 95.7 ng/g, respectively. Normal human prostatic tissue contained 1423.9 +/- 750.8 ng/g serotonin and 66.7 +/- 92.8 ng/g 5-HIAA. Recoveries ranged between 60 and 100%. The detection limits were 24 pg/injection for serotonin and 12 pg/injection for 5-HIAA. This assay provides an expeditious, specific and highly sensitive method for the simultaneous determination of monoamines in guinea pig and human prostatic tissue.  相似文献   
29.
30.
It is known that a number of factors may contribute to heart failure in the course of hypertensive heart disease. The relative importance of these factors, however, has not been established. It is maintained, on the one hand, that myocardial weakness in hypertensive heart disease is due primarily to factors resulting from the hypertension itself, and, on the other, to concominant coronary disease. The purpose of the present study is to throw some light on the relative importance of these factors.  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