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   108390篇
  免费   30066篇
  国内免费   1084篇
耳鼻咽喉   2635篇
儿科学   2799篇
妇产科学   2444篇
基础医学   3885篇
口腔科学   5486篇
临床医学   26908篇
内科学   26549篇
皮肤病学   3401篇
神经病学   13449篇
特种医学   3993篇
外科学   19367篇
综合类   340篇
现状与发展   40篇
一般理论   10篇
预防医学   14359篇
眼科学   2314篇
药学   1891篇
  1篇
中国医学   14篇
肿瘤学   9655篇
  2024年   745篇
  2023年   5079篇
  2022年   1189篇
  2021年   2861篇
  2020年   5414篇
  2019年   2119篇
  2018年   7006篇
  2017年   7418篇
  2016年   8008篇
  2015年   8080篇
  2014年   10581篇
  2013年   12467篇
  2012年   4242篇
  2011年   4071篇
  2010年   7108篇
  2009年   9396篇
  2008年   4100篇
  2007年   3071篇
  2006年   4300篇
  2005年   2805篇
  2004年   2205篇
  2003年   1912篇
  2002年   1841篇
  2001年   1957篇
  2000年   1221篇
  1999年   1780篇
  1998年   2234篇
  1997年   2054篇
  1996年   2113篇
  1995年   1826篇
  1994年   1202篇
  1993年   997篇
  1992年   833篇
  1991年   722篇
  1990年   590篇
  1989年   577篇
  1988年   579篇
  1987年   444篇
  1986年   433篇
  1985年   379篇
  1984年   368篇
  1983年   427篇
  1982年   379篇
  1981年   331篇
  1980年   268篇
  1979年   133篇
  1978年   234篇
  1977年   203篇
  1976年   177篇
  1974年   143篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Examined are several measures currently used in the assessment of child abuse, sexual abuse, and trauma. These measures include structured clinical interviews, self report measures, screening inventory, symptom checklist, and some measures that include decision making properties. Issues and implications for clinical practice are explored.  相似文献   
73.
Although a great deal is known about the nature and severity of the recent financial crisis in agriculture, there has been little systematic study of the social and psychological effects of this crisis upon farm operators and their families. Using data from a statewide sample of Iowa farmers, this study tests some hypotheses about correlates of psychological stress. The findings suggest that many farm operators find their situations to be stressful and that such stress is related to the severity of their financial problems. In addition, the life-events perspective is examined in its utility to explain how adverse economic changes impact psychological well-being.  相似文献   
74.
75.
Advancing age is associated with a remarkable number of changes in body composition, including reduction in lean body mass and increase in body fat, which have been well documented. Decreased lean body mass occurs primarily as a result of losses in skeletal muscle mass. This age-related loss in muscle mass has been termed “sarcopenia”. Loss in muscle mass accounts for the age-associated decreases in basal metabolic rate, muscle strength, and activity levels, which, in turn are the cause of the decreased energy requirements of the elderly. In sedentary persons, the main determinant of energy expenditure is fat-free mass, which declines by about 15% between the third and eighth decade of life. It also appears that declining energy needs are not matched by an appropriate decline in energy intake, with the ultimate result being increased body fat content. Increased body fatness and increased abdominal obesity are thought to be directly linked to the greatly increased incidence of non-insulin-dependent diabetes mellitus among the elderly. In this review we will discuss the extent to which regularly performed exercise can affect nutrition needs and functional capacity in the elderly. We will also discuss a variety of concerns when prescribing exercise in the elderly, such as planning for a wide variability in functional status, medical status, and training intensity and duration. Finally, we will attempt to provide some basic guidelines for beginning an exercise program for older men and women and establishing community-based programs.  相似文献   
76.
77.
78.
79.
Objective: To determine the effect of indwelling versus intermittent feeding tube placement on weight gain, apnea, and bradycardia in premature neonates.
Design: Eligible subjects were assigned randomly to either feeding tube method. Each subject was followed for 6 days.
Setting: The study was conducted in a secondary level neonatal intensive-care unit (NICU), a tertiary level NICU in a perinatal center, and a tertiary level NICU in a referral center.
Patients/Participants: Neonates who were 24–34 weeks gestational age, developmentally appropriate for gestational age, medically stable, on full enteral feedings through an orogastric or a nasogastric tube, and not fluid restricted. Ninety-three neonates were enrolled-49 in the indwelling group and 44 in the intermittent group. Nine neonates did not complete the study.
Interventions: Nasogastric indwelling feeding tubes were placed and left in site for up to 3 days. Orogastric intermittent feeding tubes were placed for each feeding and removed at completion of the feeding.
Main outcome measures: Weight gain, apnea, and bradycardia. Results: Members of both groups had similar demographic characteristics, clinical problems, and nutritional intake. No statistical differences were found between the two groups in weight gain or episodes of apnea and bradycardia.
Conclusions: There were no statistically or clinically significant differences between the two groups. The intermittent method of feeding is more expensive. Because no clinical differences were found, the type of tube placement chosen for feeding the premature infant may be based on economics.  相似文献   
80.
In the context of an interview study concerned with self-determination in psychiatric patients, this paper describes the preconditions for and consequences of self-determination from the point of view of psychiatric patients themselves. The data were collected in semi-structured interviews with long-term psychiatric patients ( n =72) and analysed using the method of content analysis. Responses on the preconditions for self-determination were grouped into three categories: firstly, there were those who said that reference to self-determination in the case of psychiatric patients is nonsense; secondly, there were those who said that self-determination requires no preconditions; and thirdly, there were those who said that there are certain preconditions, such as the ability to think and make decisions, activity, obedience, and illness. Both positive and negative consequences were identified in situations where self-determination is maintained, but only negative consequences in situations where self-determination is lost. On the basis of these tentative results, self-determination seemed to be relevant in psychiatric nursing. We are continuing to develop and test an instrument for the evaluation of the opportunity for self-determination in clinical practice.  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