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   5674篇
  免费   321篇
  国内免费   2篇
  5997篇
  2023年   72篇
  2022年   94篇
  2021年   131篇
  2020年   190篇
  2019年   192篇
  2018年   295篇
  2017年   289篇
  2016年   261篇
  2015年   208篇
  2014年   218篇
  2013年   630篇
  2012年   376篇
  2011年   330篇
  2010年   191篇
  2009年   215篇
  2008年   257篇
  2007年   269篇
  2006年   183篇
  2005年   164篇
  2004年   149篇
  2003年   109篇
  2002年   112篇
  2001年   93篇
  2000年   77篇
  1999年   66篇
  1998年   44篇
  1997年   33篇
  1996年   28篇
  1995年   24篇
  1994年   24篇
  1993年   25篇
  1992年   27篇
  1991年   27篇
  1990年   41篇
  1989年   35篇
  1988年   23篇
  1987年   33篇
  1986年   33篇
  1985年   26篇
  1984年   29篇
  1983年   22篇
  1982年   16篇
  1979年   32篇
  1975年   20篇
  1974年   26篇
  1973年   18篇
  1972年   16篇
  1971年   16篇
  1970年   19篇
  1968年   18篇
排序方式: 共有5997条查询结果,搜索用时 15 毫秒
41.
42.
The investigation of enzyme activity in cerebrospinal fluid has been without relevant results for laboratories analysing spinal fluid. For neurochemical purposes, it is interesting that the Substance P is convered by Depeptidyl-aminopeptidase IV (DP IV), liberating dipeptides. The hydrolysis of nitroanilids of the form Xaa-Pro-NHNp in cerebrospinal fluid was analysed using them as peptidases substrates. Finally a method for measuring the activity was proposed.  相似文献   
43.
The somatic and psychosocial development of 80 subjects with manifest affective-phasic psychoses is studied retrospectively and compared with that of an identically sized control group consisting of neuropsychiatrically healthy subjects. Statistically significant differences were found particularly in the answers to questions dealing with social situation and social adaptability. Achievement at school and vocational qualifications were lower among the parents of the patients than among those of the healthy subjects. Characteristic features of the patients' childhood and adolescence were transient depression, often for no apparent cause, and maladaption, and vocational wishes were fulfilled less often than among the controls. The patients experienced greater difficulty in settling in to a new group due to their contact difficulties.  相似文献   
44.
African Americans are at significantly greater risk of hypertension and worse cardiovascular outcomes than other racialized groups, yet hypertension intervention effects remain limited. Thus, it is necessary to understand the potential mechanisms whereby interventions may be more effectively targeted to improve health. Supported by prior research evidence and guided by the Biobehavioral Family Model, this study examined associations between family relationship quality, psychological wellbeing, and self-management behaviors for African Americans with hypertension. Data were pooled from three Midlife Development in the U.S. projects, resulting in a sample of 317 African Americans (63.4% female, Mage = 53.32) with self-reported high blood pressure in the past 12 months. We tested four cross-sectional multiple mediator models, with depressed mood and environmental mastery mediating associations between family strain and exercise, smoking, problematic alcohol use, and stress-eating. Environmental mastery mediated the association between greater family strain and decreased odds of achieving recommended exercise levels; greater odds of reporting problematic alcohol use; and greater stress-eating. Though family strain was associated with depressed mood in each model, this variable did not serve as an indirect pathway to self-management behaviors. Family strain, and the potential pathway identified via environmental mastery, may be a meaningful predictor of disease self-management for African Americans with hypertension. Longitudinal studies are needed to examine directionality and to support intervention trials for improving self-management and hypertension outcomes.  相似文献   
45.
This article analyzes the relationship between competition and justice in Adam Smith in order to determine to what extent competition can promote and undermine justice. I examine how competition features in two basic motivations for human action, “the propensity to truck barter and exchange,” and “the desire of bettering our condition.” Both can be traced back to the desire for recognition, but they operate in very different ways. The former manifests itself in social cooperation, chiefly commercial exchange and the division of labor, and while it can take a competitive form, competitive success produces benefits for everyone. In contrast, the latter may manifest itself in win-lose social competition. Commercial society harnesses both motivations, and both have negative as well as positive effects. However, while Smith explicitly addresses the negative effects of excessive specialization in the division of labor, it is less clear how he thinks the negative effects of social competition can be addressed. I argue that competition can undermine justice when (i) it pits people against each other and (ii) leads to psychological corruption. I conclude with some reflections on what a focus on competition adds to our understanding of Smith's work.  相似文献   
46.
We conducted a systematic review of research on relational sacrifices in romantic relationships from 2002 to 2021 [N = 115 studies] to answer three questions: Q1: Whose voices and vantage points are represented in the research?; Q2: What types of questions are valued?; Q3: What are the reflections and connections about relational sacrifices that were learned during the review? To address Q1, we coded sample demographics of study participants on geographical location, race/ethnicity, education/income/SES, gender (i.e., gender differences explored and beyond gender binaries), sexual orientation, age, and disability, using a coding system of 1 (exclusion/absence) to 5 (focus on context-relevant experiences for underrepresented samples). Results for Q1 showed that the most frequent codes were 1 (exclusion/absence) for information about the samples' disability status, education/income/SES, and both codes for gender (i.e., gender differences explored and beyond gender binaries); when demographic information was reported, the most frequent codes were 2 (compensatory addition) for age, sexual orientation, geographical location, and race/ethnicity. To address Q2, we coded for aspects of the study designs and conceptual dimensions of sacrifice. Results for Q2 showed that a majority of the studies in our review used quantitative and close-ended measures emphasizing behavioral frequency of sacrifice. For Q3, we include our own reflections and connections about relational sacrifices, questioning research methods, and challenging assumptions drawn from existing research to move toward a more inclusive science.  相似文献   
47.
Visual context processing was investigated in both action video game players and nonplayers using the Ebbinghaus illusion task (N = 312, 39.4% female) in a cross-sectional study design. When presented in context, players showed markedly poorer target size discrimination accuracy compared with nonplayers in the 6-, 7-, 8-, and 9-years old age groups, but this difference was reduced in 10-years old group and diminished in adults. When presented in isolation (no-context), the two groups displayed similar performance in all age groups. Furthermore, nonplayers (linear) and players (bell curve) showed profoundly different age-related differences in context processing. These findings provide evidence that players might have enhanced perceptual bias to process visual context in the transition from early childhood to early adolescence, and the differences between the two groups start at early ages and continue with distinct developmental profiles.  相似文献   
48.
Animal Cognition - The alarm calls of nonhuman primates are occasionally cited as functionally equivalent to lexical word meaning in human language. Recently, however, it has become increasingly...  相似文献   
49.
The COVID-19 pandemic necessitated abrupt and substantial changes in daily life, and public health strategies intended to protect physical health can negatively affect mental health and well-being, especially for individuals with pre-existing mental health challenges. For this study, we surveyed a sample of clients (N = 94) in the summer of 2020 from a community mental health clinic in the northeast United States. A mixed-methods, concurrent triangulation design was used to (a) identify client subgroups on indicators of mental health (i.e. anxious and depressive symptoms) and emotional, psychological, and social well-being using latent profile analysis (LPA), and (b) within these subgroups, examine qualitative, thematic patterns in self-described challenges, benefits and learning related to the pandemic. The LPA revealed five distinct subgroups with various levels of symptoms and well-being, including Stagnant (moderate symptoms/moderate well-being), Languishing (high symptoms/low well-being), Flourishing (low symptoms, high well-being), Fortitudinous (high symptoms, moderate well-being) and Mobilized (moderate symptoms, high well-being). These divergent subgroups support the need to conceptualise mental health symptoms apart from well-being and assess for heterogeneous constellations of such constructs among psychotherapy clients. Thematic analysis offered additional insight into pandemic experiences within each subgroup, including attention to psychological, emotional, behavioural/lifestyle, relational, physical and ecological/contextual dimensions of self-experience, as well as the ways clients had adjusted to the pandemic's circumstances. Findings support nuanced conceptualisations of positive mental health and offer insight into coping and adaptation during this public health crisis.  相似文献   
50.
A systematic review of qualitative studies was conducted to explore how parents perceive sleep quality in their infants aged 0–24 months and the factors that influence these perceptions. A systematic search of the databases Scopus, Embase, Cinahl, PsycInfo and MEDLINE, was undertaken to identify eligible peer-reviewed studies published between 2006–2021. Ten papers met inclusion criteria and were subsequently included in the review. Evaluation of papers with the Critical Appraisal Skills Programme qualitative checklist classified papers as weak, moderate or strong, with half considered strong. Thematic synthesis identified one superordinate theme, culture, and five interrelated subordinate themes regarding how parents perceive their infant's sleep and the factors that may influence these perceptions. These themes were: (1) Infants physical and emotional comfort; (2) Beliefs regarding safety; (3) Parental and familial wellbeing; (4) Perceived degree of infant agency; (5) Influence of external beliefs and opinions. The findings from this review may assist practitioners in providing parents with personalized and culturally sensitive information regarding infant sleep and may also inform antenatal and early intervention practices, subsequently minimizing parental distress regarding infant sleep patterns.  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