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   924篇
  免费   120篇
  国内免费   5篇
儿科学   16篇
妇产科学   15篇
基础医学   84篇
口腔科学   36篇
临床医学   260篇
内科学   78篇
皮肤病学   3篇
神经病学   239篇
特种医学   4篇
外科学   42篇
综合类   23篇
预防医学   164篇
眼科学   4篇
药学   34篇
  1篇
中国医学   2篇
肿瘤学   44篇
  2024年   2篇
  2023年   31篇
  2022年   20篇
  2021年   41篇
  2020年   78篇
  2019年   76篇
  2018年   68篇
  2017年   60篇
  2016年   46篇
  2015年   40篇
  2014年   45篇
  2013年   98篇
  2012年   39篇
  2011年   36篇
  2010年   29篇
  2009年   23篇
  2008年   39篇
  2007年   38篇
  2006年   28篇
  2005年   32篇
  2004年   24篇
  2003年   32篇
  2002年   13篇
  2001年   19篇
  2000年   15篇
  1999年   8篇
  1998年   13篇
  1997年   11篇
  1996年   2篇
  1995年   8篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   4篇
  1989年   1篇
  1988年   2篇
  1987年   4篇
  1986年   2篇
  1985年   5篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1976年   1篇
排序方式: 共有1049条查询结果,搜索用时 11 毫秒
1.
The Adelaide Diagnostic Learning Inventory (ADLIMS) is a measure of learning styles and learning pathologies that was designed to investigate the impact of traditional approaches to learning versus problem-based learning and to identify students whose approach to learning tasks predicted poor academic performance. In this study, some important psychometric properties of the ADLIMS were examined, including its factor structure. In this study, factor replicability across samples was argued to provide a more robust and psychologically meaningful factor solution than that which can be obtained using traditional mathematical criteria. The results of the factor analysis did not confirm the presence of the four factor solution earlier reported for the ADLIMS, but did identify three clear factors that had very high replicability. An inspection of the items comprising these three factors showed that factor 1 tapped subjective distress related to poor study habits, lack of motivation to study, and distraction from social activities. Factor 2 tapped distress arising from high achievement expectations that were hampered by superficial or disorganized study habits that did not enable the student to grasp the relationships between concepts and ideas. Factor 3 tapped positive feelings and a sense of satisfaction associated with a problem-based approach to the learning of new study material. Although the internal reliability of the ADLIMS subscales met the requirements of a measure to be used in general research such as in the investigation of correlates among groups of medical students, they did not meet the higher requirements of a measure to be used to identify or predict individuals with pathological learning styles.  相似文献   
2.
We assessed the feasibility and psychometric properties of two commonly used health status questionnaires in Parkinson's disease (PD): the generic Nottingham Health Profile (NHP) and the disease-specific 39-item Parkinson's disease Questionnaire (PDQ-39), from a cross-sectional postal survey of PD patients (N = 81), using traditional and Rasch measurement methodologies. Overall response rate was 88%. Both questionnaires were found feasible, although the NHP performed less well. The PDQ-39 had fewer floor effects and was better able to separate respondents into distinct groups than the NHP, whereas the latter exhibited less ambiguous dimensionality and better targeting of respondents with non-extreme scores. Reliability and validity indices were similar, and potential differential item functioning by age and gender groups was found for both questionnaires. PDQ-39 response alternatives indicated ambiguity. With few exceptions, questionnaire scales were unable to meet recommended standards fully. While preliminary, this study illustrates the need for thorough evaluation of outcome measures and has implications beyond the questionnaires used here. Although promising, both questionnaires warrant further developmental work and stronger support of measurement validity before they could be considered fully suitable for valid use in PD, in particular in earlier stages of the disease.  相似文献   
3.
In a double-blind, placebo-controlled study, the pharmacokinetic, encephalotropic, and psychotropic properties of a new metabolically active thienyl-piperazine derivative were studied in ten elderly subjects in their sixties by means of quantitative EEG and psychometric analyses. At weekly intervals, they received randomized single oral doses of placebo; 75 mg, 150 mg, and 300 mg tenilsetam (CAS 997); and 3.2 g piracetam as reference drug. Blood sampling EEG recordings, psychometric and psychophysiological tests, as well as the monitoring of blood pressure, heart rate, and side effects were carried out at 0, 2, 4, 6, 8, and 24 hr. Pharmacokinetic investigations showed that CAS 997 was rather well absorbed, as peak concentrations were observed consistently at 2 hr and were clearly dose-dependent. The terminal half-life was between 18 and 22 hr, as compared with 6 hr for the reference drug piracetam, which also exhibited plasma peaks at 2 hr. Computer-assisted spectral analyses of the EEG showed a significant CNS effect of CAS 997 as compared with placebo, characterized by an increase of alpha activity, decrease of delta activity, and fast beta activity, as well as by tendency towards an augmentation of total power and decrease of the centroid and centroid deviation of the total beta activity. Partly similar though less pronounced alterations were exhibited by 3.2 g piracetam. Such changes were described previously by us after several other antihypoxidotics/nootropics and are indicative of improvement in vigilance. Dose/treatment–efficacy calculations demonstrated 75 and 150 mg CAS 997 superior both to placebo and the reference compound but also to the highest given dosis (300 mg CAS 997). Time–efficacy calculations showed two pharrnacodynamic peaks: one in the 4th and another one in the 8th to 24th hour. The time lag between pharmacokinetic and -dynamic changes may be due to the penetration of the drug through the blood brain barrier to a deep compartment receptor as well as to the formation of active metabolites. Psychometric investigations showed only small and inconsistent psychotropic effects after single doses of CAS 997 in elderlies. Evaluation of pulse rate, blood pressure, and side effects showed a good tolerability of both drugs.  相似文献   
4.
A model is presented which allows for the contribution of genes and environment to categorical data on multiple symptoms. The model distinguishes between parameters needed to express the relationship between a latent trait and observed responses and the parameters required to represent the causes of variation in the latent trait. The regression of the latent trait on covariates may also be specified. The model is applied to symptoms of depression in 1983 pairs of adult female monozygotic and dizygotic twins. A model which allows only for polygenic variation in the latent trait is supported as well as the mixed model, which also allows for the effects of a major gene. The likelihood is significantly lower when all genetic effects are ascribed to a single gene. Practical limitations of the method are discussed.This research is supported by Grants AG04954, AA06781, GM32782, GM30250, and MH40828 from the National Institutes of Health. We are indebted to Dr. Greg Carey for his incisive discussion.  相似文献   
5.
6.
7.
ObjectiveOne of the primary tools in the assessment of individual‐level patient outcomes is Jacobson and Truax, (1991’s) Reliable Change Index (RCI). Recent efforts to optimize the RCI have revolved around three issues: (a) extending the RCI beyond two timepoints, (b) estimating the RCI using scale scores from item response theory or factor analysis and (c) estimation of person‐ and time‐specific standard errors of measurement.MethodWe present an adaptation of a two‐stage procedure, a measurement error‐corrected multilevel model, as a tool for RCI estimation (with accompanying Statistical Analysis System syntax). Using DASS‐21 data from a community‐based mental health center (N = 379), we illustrate the potential for the model as unifying framework for simultaneously addressing all three limitations in modeling individual‐level RCI estimates.ResultsCompared to the optimal‐fitting RCI model (moderated nonlinear factor analysis scoring with measurement error correction), an RCI model that uses DASS‐21 total scores produced errors in RCI inferences in 50.8% of patients; this was largely driven by overestimation of the proportion of patients with statistically significant improvement.ConclusionEstimation of the RCI can now be enhanced by the use of latent variables, person‐ and time‐specific measurement errors, and multiple timepoints.  相似文献   
8.
9.
用临床记忆量表测定了40例脑梗塞患者和37例健康人。结果表明脑梗塞患者有显著的短时记忆障碍,梗塞部位、面积、病程与记忆障碍有一定关系,无意义图形再认与右脑功能关系最密切,其他分测验两侧半球区别不显著。  相似文献   
10.
①目的 分析性传播疾病病人的心理健康状况。②方法 随机选取我院皮肤性病门诊病人 1 0 0例(男 5 8例 ,女 4 2例 ) ,采用SCL 90量表对其心理健康状况进行统计分析。③结果 与全国常模比较 ,性病病人除敌对和偏执因子评分外 ,SCL 90其他因子评分均显著升高 (t或t′ =2 .34~ 9.5 9,P <0 .0 5、0 .0 0 1 ) ;而与男性病人相比 ,女性病人的恐惧、焦虑和忧郁因子评分显著升高 (t=3.4 9~ 5 .5 2 ,P <0 .0 1 )。④结论 性传播疾病病人的心理状态变化显著 ,而女性病人的变化更值得关注  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