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   671篇
  免费   55篇
  国内免费   44篇
  770篇
  2024年   3篇
  2023年   26篇
  2022年   19篇
  2021年   39篇
  2020年   42篇
  2019年   41篇
  2018年   41篇
  2017年   33篇
  2016年   42篇
  2015年   22篇
  2014年   29篇
  2013年   69篇
  2012年   18篇
  2011年   17篇
  2010年   23篇
  2009年   22篇
  2008年   16篇
  2007年   30篇
  2006年   23篇
  2005年   26篇
  2004年   31篇
  2003年   18篇
  2002年   13篇
  2001年   11篇
  2000年   11篇
  1999年   7篇
  1998年   16篇
  1997年   12篇
  1996年   8篇
  1995年   10篇
  1994年   6篇
  1993年   10篇
  1992年   7篇
  1991年   6篇
  1990年   3篇
  1989年   3篇
  1987年   2篇
  1986年   1篇
  1985年   3篇
  1983年   1篇
  1982年   2篇
  1980年   2篇
  1979年   2篇
  1978年   3篇
  1977年   1篇
排序方式: 共有770条查询结果,搜索用时 15 毫秒
61.
对大连地区健康成人血清总胆固醇(TC)、血清甘油三脂(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)进行调查研究.选取2009年4月至2010年12月大连地区16 052名健康体检者,并按性别和年龄分组.早晨空腹,采集所有调查对象3ml肝素抗凝血,用日立7060全自动生化分析仪检测血清TC、TG、HDL-C和LDL-C的结果.结果大连地区健康成人血脂水平比2007年发表的中国成人血脂异常防治指南所确定的正常参考区间偏高,因此,我们对大连地区人们的血脂水平必须引起高度重视,以预防和减少高脂血症及其相关疾病的发生.  相似文献   
62.
Researchers studying the movements of the human body often encounter data measured in angles (e.g., angular displacements of joints). The evaluation of these circular data requires special statistical methods. The authors introduce a new test for the analysis of order-constrained hypotheses for circular data. Through this test, researchers can evaluate their expectations regarding the outcome of an experiment directly by representing their ideas in the form of a hypothesis containing inequality constraints. The resulting data analysis is generally more powerful than one using standard null hypothesis testing. Two examples of circular data from human movement science are presented to illustrate the use of the test. Results from a simulation study show that the test performs well.  相似文献   
63.
《Estudios de Psicología》2013,34(2):161-174
Abstract

The objectives of this study are 1) to analyze the effectiveness of a writing composition intervention program aimed to increase children's writing performance and other personal variables; 2) to analyze whether implementation in the environment (school and home) or responsible figures (parents and teachers) produced different effects in program effectiveness; and 3) to check whether increasing parental involvement in doing homework was sufficient to improve children's outcomes or whether prior family training is required to enable them to be efficient. The sample consisted of 112 students (5th-6th grade) and their families. 26 of them made up the EFP group (mothers implementing a writing program), 25 of them were assigned to the PAD group (mothers increasing help with writing homework), 35 to the PRO group (teachers applying a writing program) and 26 to the OC group (ordinary curriculum). We analyze the results and present and discuss our conclusions.  相似文献   
64.
The authors demonstrate how collecting quantitative data via psychometrically sound quantitative instruments during the qualitative interview process enhances interpretations by helping researchers better contextualize qualitative findings, specifically through qualitative dominant crossover mixed analyses. They provide an example of this strategy, whereby a baseline was established using a quantitative scale and normative data to help interpret qualitative interviews, resulting in what they call a mixed methods interview. Philosophical and practical implications are discussed.  相似文献   
65.
Mechanical Turk (MTurk), an online labor system run by Amazon.com, provides quick, easy, and inexpensive access to online research participants. As use of MTurk has grown, so have questions from behavioral researchers about its participants, reliability, and low compensation. In this article, we review recent research about MTurk and compare MTurk participants with community and student samples on a set of personality dimensions and classic decision‐making biases. Across two studies, we find many similarities between MTurk participants and traditional samples, but we also find important differences. For instance, MTurk participants are less likely to pay attention to experimental materials, reducing statistical power. They are more likely to use the Internet to find answers, even with no incentive for correct responses. MTurk participants have attitudes about money that are different from a community sample's attitudes but similar to students' attitudes. Finally, MTurk participants are less extraverted and have lower self‐esteem than other participants, presenting challenges for some research domains. Despite these differences, MTurk participants produce reliable results consistent with standard decision‐making biases: they are present biased, risk‐averse for gains, risk‐seeking for losses, show delay/expedite asymmetries, and show the certainty effect—with almost no significant differences in effect sizes from other samples. We conclude that MTurk offers a highly valuable opportunity for data collection and recommend that researchers using MTurk (1) include screening questions that gauge attention and language comprehension; (2) avoid questions with factual answers; and (3) consider how individual differences in financial and social domains may influence results. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
66.
Ecological momentary assessments (EMA) of anxiety and anger/hostility were obtained every 25–30 min over two 24-h periods, separated by a median of 6 months, from 165 employees at a university in the Northeast. We used a multilevel trait-state-error structural equation model to estimate: (1) the proportion of variance in EMA anxiety and anger/hostility attributable to stable trait-like individual differences; (2) the correspondence between these trait-like components of EMA anxiety and anger/hostility and traditional questionnaire measures of each construct; and (3) the test–retest correlation between two 24-h averages obtained several months apart. After adjustment for measurement error, more than half the total variance in EMA reports of anxiety and anger/hostility is attributable to stable trait-like individual differences; however, the trait-like component of each construct is only modestly correlated with questionnaire measures of that construct. The 6-month “test–retest” correlations of latent variables representing the true 24-h EMA average anxiety and average anger are quite high (r ? 0.83). This study represents the longest follow-up period over which EMA-based estimates of traits have been examined. The results suggest that although the trait component (individual differences) of EMA momentary ratings of anxiety and anger is larger than the state component, traditional self-report questionnaires of trait anxiety and anger correspond only weakly with EMA-defined traits.  相似文献   
67.
A key challenge in the fabrication of superhard nanocomposite films is how to control the distribution of grain sizes in these materials. High-resolution transmission electron microscopy has been used to measure nanograin-size distributions in the Ti–B–N films with various B contents. The results show that the mean grain size decreases with increase of B content and the grain-size distribution conforms to a log-normal function when the hardness approaches a maximum value. The transition from normal to log-normal distributions can be determined by analysis in terms of a minimum information criterion. The origin of a log-normal size distribution probably results from heterogeneity arising from a diffusion-drift process.  相似文献   
68.
The present article reviews the history and emerging trends in the field of psychobiography. Five historical periods are highlighted: hagiography and pre-19th century study of lives; Freud and applied psychoanalysis; psychodynamic extensions and personology; modern multi-theoretical models; and psychobiography as interdisciplinary science. The author advocates for a science of psychobiography manifested in expanded and empirically validated theoretical models anchoring research. Further, attention is drawn to the need for more rigorous historiographic research methods weighting first-person sources and incorporating mixed methods designs. Increased attention to ethical and legal issues in the conduct and reporting of psychobiographical studies is also highlighted. Finally, emerging trends in psychobiography related to research production, academic training, and organisational initiatives are presented.  相似文献   
69.
It is essential that outcome research permit clear conclusions to be drawn about the efficacy of interventions. The common practice of nesting therapists within conditions can pose important methodological challenges that affect interpretation, particularly if the study is not powered to account for the nested design. An obstacle to the optimal design of these studies is the lack of data about the intraclass correlation coefficient (ICC), which measures the statistical dependencies introduced by nesting. To begin the development of a public database of ICC estimates, the authors investigated ICCs for a variety outcomes reported in 20 psychotherapy outcome studies. The magnitude of the 495 ICC estimates varied widely across measures and studies. The authors provide recommendations regarding how to select and aggregate ICC estimates for power calculations and show how researchers can use ICC estimates to choose the number of patients and therapists that will optimize power. Attention to these recommendations will strengthen the validity of inferences drawn from psychotherapy studies that nest therapists within conditions.  相似文献   
70.
This work proposes an approach to cluster and sort a set of alternatives considering multi‐criteria categories with a partial order structure. It can be considered a heuristic approach because it does not attempt to derive an optimal partial order among all conceivable clusters of alternatives. Rather than this, it intends to be a simple approach that is transparent to the Decision Maker (DM) whose assistance is sought to help shaping the results. The approach proposed arises from the conjugation of traditional Clustering analysis and Multi‐criteria sorting tools. At the outset, the number of categories and their characteristics is unknown. First, we need to detect only the clusters themselves on the basis of a similarity measure independent of the preferences of the DM. Next, we detect potential partial order relations that might exist between them, according to the subjective preferences of the DM. Such preferences are elicited only after the DM has examined the clusters detected and deemed that these categories made sense. The new approach performs very well in a real‐world problem of management of intragroup conflicts and conflict handling strategies. Copyright © 2012 John Wiley & Sons, Ltd.  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