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   94092篇
  免费   29113篇
  国内免费   1057篇
耳鼻咽喉   2371篇
儿科学   2521篇
妇产科学   2242篇
基础医学   1989篇
口腔科学   5005篇
临床医学   25595篇
内科学   23705篇
皮肤病学   3222篇
神经病学   11854篇
特种医学   3472篇
外科学   17479篇
综合类   120篇
现状与发展   40篇
预防医学   13109篇
眼科学   2061篇
药学   858篇
中国医学   5篇
肿瘤学   8614篇
  2024年   739篇
  2023年   5003篇
  2022年   1053篇
  2021年   2633篇
  2020年   5268篇
  2019年   1921篇
  2018年   6763篇
  2017年   7244篇
  2016年   7818篇
  2015年   7889篇
  2014年   10260篇
  2013年   11908篇
  2012年   3422篇
  2011年   3163篇
  2010年   6621篇
  2009年   8923篇
  2008年   3199篇
  2007年   2125篇
  2006年   3305篇
  2005年   1881篇
  2004年   1275篇
  2003年   965篇
  2002年   902篇
  2001年   1787篇
  2000年   1122篇
  1999年   1658篇
  1998年   2041篇
  1997年   1873篇
  1996年   1932篇
  1995年   1674篇
  1994年   1072篇
  1993年   906篇
  1992年   751篇
  1991年   643篇
  1990年   512篇
  1989年   524篇
  1988年   506篇
  1987年   383篇
  1986年   358篇
  1985年   297篇
  1984年   255篇
  1983年   301篇
  1982年   226篇
  1981年   202篇
  1980年   125篇
  1978年   123篇
  1977年   116篇
  1976年   86篇
  1974年   73篇
  1972年   76篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
The aim of this study was to design a new intravenous blood–gas exchange device and to estimate the design characteristics of the device with a dimensionless function by using a substance that can be used instead of bovine blood. In addition, the characteristics of oxygen transfer were estimated using empirical formulas and the reliability of the equations was ascertained by comparing their output with an experiment performed using bovine blood. The dimensionless function was derived using distilled water and bovine blood to estimate the oxygen transfer rate. Using the derived equations, the calculated oxygen transfer rates for bovine blood and distilled water were similar for Reynolds numbers ranging from 0.7 to 7.0. Therefore, it is possible to estimate the oxygen transfer rate in bovine blood, which is a non-Newtonian fluid, using distilled water, which is a Newtonian fluid. Moreover, it was possible to verify the related equations because the oxygen transfer rate could be estimated using the derived equations, according to the diameters of the various device modules.  相似文献   
14.
15.
The present study demonstrates that alcohol-induced memory impairment can be attenuated by pretreatment with an oral tryptophan supplementation. These results provide support for the role of a brain serotonin deficit in this impairment and highlight the impact a dietary manipulation can have on a complex behavioral process.  相似文献   
16.
17.
The definition of envy is commonly based on psychoanalytical views of organizational culture. The purpose of this paper is to describe envy in a nursing community. The population study consisted of random sample of 120 subjects drawn from among the employees of one central hospital in Finland. The study material consisted of data collected by questionnaires (response rate 65%). The data were processed by various statistical methods. Open-ended questions were analysed by inductive content analysis. The results of this study indicated that the employee's view of his/her official position in the nursing community, his/her relationships with his/her fellow workers and the management as well as relationships with other nursing communities are all related to envy. The employee's view of his/her official position intensified his/her feelings of envy, if he/she had other negative feelings, anxiety, dissatisfaction with him/herself, and negative feelings towards fellow workers. The major object of envy was fellow workers' salaries. Envy towards other nursing communities was generated by alleged differences in the amount of labour, or by the charge nurse's greater interest in other sections. Employees coped with envy by hiding these feelings and being modest. Women coped with envy by being silent, while men denied the value of the object of envy.  相似文献   
18.
19.
Psychological Consequences of Food Restriction   总被引:1,自引:0,他引:1  
A review of the literature and research on food restriction indicates that inhibiting food intake has consequences that may not have been anticipated by those attempting such restriction. Starvation and self-imposed dieting appear to result in eating binges once food is available and in psychological manifestations such as preoccupation with food and eating, increased emotional responsiveness and dysphoria, and distractibility. Caution is thus advisable in counseling clients to restrict their eating and diet to lose weight, as the negative sequelae may outweigh the benefits of restraining one's eating. Instead, healthful, balanced eating without specific food restrictions should be recommended as a long-term strategy to avoid the perils of restrictive dieting. J Am Diet Assoc. 1996; 96:589-592.  相似文献   
20.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  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