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   1340篇
  免费   77篇
  国内免费   34篇
儿科学   47篇
妇产科学   21篇
基础医学   138篇
口腔科学   14篇
临床医学   139篇
内科学   209篇
皮肤病学   17篇
神经病学   87篇
特种医学   180篇
外科学   77篇
综合类   24篇
预防医学   204篇
眼科学   22篇
药学   46篇
中国医学   1篇
肿瘤学   225篇
  2022年   13篇
  2021年   14篇
  2020年   30篇
  2019年   27篇
  2018年   31篇
  2017年   19篇
  2016年   25篇
  2015年   36篇
  2014年   56篇
  2013年   45篇
  2012年   63篇
  2011年   57篇
  2010年   49篇
  2009年   69篇
  2008年   62篇
  2007年   82篇
  2006年   63篇
  2005年   69篇
  2004年   37篇
  2003年   45篇
  2002年   58篇
  2001年   40篇
  2000年   28篇
  1999年   42篇
  1998年   32篇
  1997年   46篇
  1996年   25篇
  1995年   18篇
  1994年   11篇
  1993年   19篇
  1992年   22篇
  1991年   9篇
  1990年   13篇
  1989年   23篇
  1988年   30篇
  1987年   19篇
  1986年   19篇
  1985年   10篇
  1984年   10篇
  1983年   7篇
  1982年   4篇
  1981年   6篇
  1979年   8篇
  1977年   7篇
  1976年   4篇
  1975年   4篇
  1974年   4篇
  1971年   8篇
  1969年   9篇
  1967年   5篇
排序方式: 共有1451条查询结果,搜索用时 687 毫秒
41.
Primary hepatic lymphoma is an extremely rare malignancy accounting for 0.016% of all cases of non-Hodgkin lymphomas. Approximately 1–4% of histologies described show a follicular pattern. We report a case of primary hepatic non-Hodgkin lymphoma that developed in a middle-aged woman 3 years after radical treatment (neoadjuvant chemoradiotherapy and surgery) for a rectal adenocarcinoma. Abdomen ultrasound showed a single nodule in the liver, which raised the issue of differential diagnosis with a metastasis from rectal cancer. After surgical removal of the nodule, histology revealed a primary B cell, stage IE follicular non-Hodgkin lymphoma, confined to the liver; indeed, no foci of lymphoma were found elsewhere in the body.  相似文献   
42.
Abstract

The effect of therapists in psychotherapy is a much debated topic, with a number of studies showing therapist variance being large while other studies show little or no variability in outcomes due to therapists. The aim of this study was to investigate therapist effects in a well-defined sample of patients and therapists from an outpatient service which specializes in providing cognitive behaviour therapy (CBT) for patients with chronic fatigue syndrome (CFS). Therapy was provided in a highly specialized clinical setting for CFS and was delivered by qualified CBT therapists with at least 2 years experience with this client group. Three hundred and seventy-four patients with CFS and 12 cognitive behavioural psychotherapists took part. Therapist effects on the primary outcomes of fatigue and disability were investigated with multilevel random effects models and variance component analysis. Different models were computed and compared. Results showed a reduction in fatigue and disability scores after therapy. Variance explained by therapists, when demographic covariates were accounted for, was 0% for fatigue and under 2% for disability. A number of important factors may have played a significant role in minimizing therapist effects in our study. These are: specialist setting, single centre, patients with the same primary diagnosis, therapists of the same orientation and training, shared environment and supervision. Future studies may stress the importance of these factors in the investigation of the therapist effect in psychotherapy.  相似文献   
43.
Background

Cognitive difficulties are common in people with severe mental disorders (SMDs) and various measures of cognition are of proven validity. However, there is a lack of systematic evidence regarding the psychometric properties of these measures in low- and middle-income countries (LMICs).

Objective

To systematically review the psychometric properties of cognitive measures validated in people with SMDs in LMICs.

Methods

We conducted a systematic review of the literature by searching from four electronic databases. Two authors independently screened studies for their eligibility. Measurement properties of measures in all included studies were extracted. All eligible measures were assessed against criteria set for clinical and research recommendations. Results are summarized narratively and measures were grouped by measurement type and population.

Results

We identified 23 unique measures from 28 studies. None of these was from low-income settings. Seventeen of the measures were performance-based. The majority (n = 16/23) of the measures were validated in people with schizophrenia. The most commonly reported measurement properties were: known group, convergent, and divergent validity (n = 25/28). For most psychometric property, studies of methodological qualities were found to be doubtful. Among measures evaluated in people with schizophrenia, Brief Assessment of Cognition in Schizophrenia, Cognitive Assessment Interview, MATRICS Consensus Cognitive Battery, and CogState Schizophrenia Battery were with the highest scores for clinical and research recommendation.

Conclusions

Studies included in our review provide only limited quality evidence and future studies should consider adapting and validating measures using stronger designs and methods. Nonetheless, validated assessments of cognition could help in the management and allocating therapy in people with SMDs in LMICs.

  相似文献   
44.

Background

The Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue Scale is an internationally used validated measure. General population–based age- and sex-specific percentile norms are, however, not published to date, although these are needed as reference for the interpretation of clinical research data.

Objectives

To assess the FACIT-Fatigue Scale in a large representative sample of the German general population to examine psychometric characteristics and factorial structure and to provide population-based norms.

Methods

A nationally representative face-to-face household survey was conducted in Germany using the FACIT-Fatigue Scale. Item characteristics were examined. Internal consistency was determined using the Cronbach α. Dimensionality was analyzed using confirmatory factor analysis (CFA) and bifactor analysis. Scale score differences relating to sex and age were assessed. Sex- and age-specific percentiles were computed for the entire scale range.

Results

Of 2426 participants, 55.7% were women, and the mean age was 49.8 ± 17.4 years. The FACIT-Fatigue Scale mean was 43.5 ± 8.3. Cronbach α was high at 0.92. Although fit indices of the CFA were below desired levels (root mean squared error of approximation = 0.144, comparative fit index = 0.846, and Tucker-Lewis index = 0.815), item loadings in the CFA and bifactor analysis confirm the scale’s unidimensionality. Women were more fatigued than men, and participants who were 70 years or older showed higher fatigue scores than younger respondents. Thus, sex- and age-specific population-based percentiles were provided.

Conclusions

Reliability and validity of the German translation of the FACIT-Fatigue Scale were confirmed. This study provides general population–based sex- and age-specific FACIT-Fatigue Scale percentile norms for the first time, thereby contributing to a meaningful interpretation of clinical research data.  相似文献   
45.
46.
Plasma beta-thromboglobulin (beta TG) levels were measured in 103 healthy controls and 112 patients suffering from either peripheral vascular disease (PVD), or cerebrovascular disease (CVD) or deep vein thrombosis (DVT). Plasma beta TG was significantly elevated in 46 PVD patients and 24 recent DVT patients compared to controls, but did not differ significantly in 18 chronic DVT and 24 old CVD patients. In addition, heparin neutralizing activity (HNA) and platelet aggregation induced by adenosine diphosphate, 1-epinephrine and thrombin were compared in 33 out of the 46 PVD patients to 33 controls. The mean HNA was significantly shorter in the PVD patients than in controls. The rate and extent of platelet aggregation were increased in PVD patients compared to controls, but the difference was not statistically significant. Platelet production time (PPT) was measured in 20 controls, 35 PVD patients, nine chronic DVT and 12 chronic CVD patients; significantly shorter PPT was only observed in 14 patients with advanced PVD compared to controls, suggesting increased platelet consumption in these patients. All four assays (plasma beta TG, HNA, platelet aggregation and PPT) were performed in 25 patients; no correlation between the four tests was found in these patients suggesting that the tests were measuring various aspects of platelet function. These results suggest that in vivo platelet consumption as well as platelet aggregation and 'release reaction' are presumably enhanced in PVD and recent DVT patients and that plasma beta TG and PPT assays may be better and more specific indicators of in vivo platelet activation than in vitro platelet aggregation test.  相似文献   
47.
48.
The relationships between heart rate variability (HRV), left ventricular mass and diastolic function in borderline hypertensive patients (BHT) were evaluated. 24 h Holter electrocardiogram (ECG) and blood pressure (BP) monitoring, M and 2 D echocardiogram and Doppler analysis in 42 BHT with and without left ventricular hypertrophy (LVH) and in 20 normotensive controls were assessed. From 24-h ECG, time domain indexes of HRV were calculated. Standard Deviation of all Cycles (SDNN) and Standard Deviation of the means of heart periods over five-minute intervals (SDANN) were significantly reduced in BHT with LVH but not in BHT without LVH. No significant differences of short-term variability measures were detectable, although a progressive decrease among control subjects and BHT with and without LVH was observed. Diastolic left ventricular compliance evaluated by early to late transmitral flow velocity ratio (E/A ratio) significantly declined from normotensive subjects to BHT with LVH. There was a significant positive correlation between E/A and SDNN and SDANN throughout all studied groups. This indicates that BHT with LVH has a reduced HRV compared to other groups. This impairment is probably related to left ventricular mass and left ventricular filling abnormalities.  相似文献   
49.

Background

Although the use of patient-reported outcome measures (PROs) has increased markedly, clinical interpretation of scores remains lacking. We developed a method to identify clinical severity thresholds for pain, fatigue, depression, and anxiety in people with cancer.

Methods

Using available Patient-Reported Outcomes Measurement Information System (PROMIS) item bank response data collected on 840 cancer patients, symptom vignettes across a range of symptom severity were developed and placed on index cards. Cards represented symptom severity at five-point intervals differences on the T score metric [mean = 50; standard deviation (SD) = 10]. Symptom vignettes for each symptom were anchored on these standardized scores at 0.5 SD increments across the full range of severity. Clinical experts, blind to the PROMIS score associated with each vignette, rank-ordered the vignettes by severity, then arrived at consensus regarding which two vignettes were at the upper and lower boundaries of normal and mildly symptomatic for each symptom. The procedure was repeated to identify cut scores separating mildly from moderately symptomatic, and moderately from severely symptomatic scores. Clinician severity rankings were then compared to the T scores upon which the vignettes were based.

Results

For each of the targeted PROs, the severity rankings reached by clinician consensus perfectly matched the numerical rankings of their associated T scores. Across all symptoms, the thresholds (cut scores) identified to differentiate normal from mildly symptomatic were near a T score of 50. Cut scores differentiating mildly from moderately symptomatic were at or near 60, and those separating moderately from severely symptomatic were at or near 70.

Conclusions

The study results provide empirically generated PROMIS T score thresholds that differentiate levels of symptom severity for pain interference, fatigue, anxiety, and depression. The convergence of clinical judgment with self-reported patient severity scores supports the validity of this methodology to derive clinically relevant symptom severity levels for PROMIS symptom measures in other settings.  相似文献   
50.

Purpose

The Patient Reported Outcomes Measurement Information System (PROMIS ® ) is a US National Institutes of Health initiative that has produced self-report outcome measures, using a framework of physical, mental, and social health defined by the World Health Organization in 1948 (WHO, in Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 1948). The World Health Organization’s International Classification of Functioning, Disability and Health (ICF) is a comprehensive classification system of health and health-related domains that was put forward in 2001. The purpose of this report is to compare and contrast PROMIS and ICF conceptual frameworks to support mapping of PROMIS instruments to the ICF classification system .

Methods

We assessed the objectives and the classification schema of the PROMIS and ICF frameworks, followed by content analysis to determine whether PROMIS domain and sub-domain level health concepts can be linked to the ICF classification.

Results

Both PROMIS and ICF are relevant to all individuals, irrespective of the presence of health conditions, person characteristics, or environmental factors in which persons live. PROMIS measures are intended to assess a person’s experiences of his or her health, functional status, and well-being in multiple domains across physical, mental, and social dimensions. The ICF comprehensively describes human functioning from a biological, individual, and social perspective. The ICF supports classification of health and health-related states such as functioning, but is not a specific measure or assessment of health, per se. PROMIS domains and sub-domain concepts can be meaningfully mapped to ICF concepts.

Conclusions

Theoretical and conceptual similarities support the use of PROMIS instruments to operationalize self-reported measurement for many body function, activity and participation ICF concepts, as well as several environmental factor concepts. Differences observed in PROMIS and ICF conceptual frameworks provide a stimulus for future research and development.  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