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   34654篇
  免费   2631篇
  国内免费   756篇
耳鼻咽喉   173篇
儿科学   806篇
妇产科学   195篇
基础医学   3124篇
口腔科学   394篇
临床医学   5570篇
内科学   8481篇
皮肤病学   101篇
神经病学   4421篇
特种医学   1738篇
外国民族医学   1篇
外科学   3811篇
综合类   3702篇
预防医学   1422篇
眼科学   214篇
药学   2025篇
  23篇
中国医学   1130篇
肿瘤学   710篇
  2024年   119篇
  2023年   680篇
  2022年   1278篇
  2021年   1760篇
  2020年   1485篇
  2019年   1548篇
  2018年   1432篇
  2017年   1320篇
  2016年   1249篇
  2015年   1351篇
  2014年   2521篇
  2013年   2514篇
  2012年   1793篇
  2011年   2035篇
  2010年   1650篇
  2009年   1637篇
  2008年   1606篇
  2007年   1549篇
  2006年   1407篇
  2005年   1103篇
  2004年   979篇
  2003年   820篇
  2002年   715篇
  2001年   544篇
  2000年   455篇
  1999年   382篇
  1998年   350篇
  1997年   346篇
  1996年   335篇
  1995年   268篇
  1994年   264篇
  1993年   203篇
  1992年   190篇
  1991年   180篇
  1990年   133篇
  1989年   123篇
  1988年   146篇
  1987年   116篇
  1986年   106篇
  1985年   150篇
  1984年   175篇
  1983年   105篇
  1982年   119篇
  1981年   108篇
  1980年   112篇
  1979年   85篇
  1978年   70篇
  1977年   78篇
  1976年   82篇
  1975年   73篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, = 0.352; pose 3, p < 0.001, = 0.454; pose 4, p = 0.004, = 0.334), inverted (pose 4, p = 0.027, = 0.234; pose 5,p = 0.034, = 0.221), and externally rotated (pose 4, p = 0.037, = 0.217; pose 5; p = 0.004, = 0.331) than those of healthy controls during the mid‐stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860–1867, 2019  相似文献   
2.
功能性便秘的发生严重困扰着现代人群,进而影响人们的生活质量。杜长海名老中医认为功能性便秘究其内因为大肠传导失常,外因乃现代人的生活方式、紧张的生活氛围等等,因此杜老结合自己数十年的临床经验,根据中医辨证总结出临床常用药对,对有效治疗功能性便秘进行了经验总结。  相似文献   
3.

Context

Family caregivers constitute a critical component of the end-of-life care system with considerable cost to themselves. However, the joint association of terminally ill cancer patients' symptom distress and functional impairment with caregivers' subjective caregiving burden, quality of life (QOL), and depressive symptoms remains unknown.

Objectives/Methods

We used multivariate hierarchical linear modeling to simultaneously evaluate associations between five distinct patterns of conjoint symptom distress and functional impairment (symptom-functional states) and subjective caregiving burden, QOL, and depressive symptoms in a convenience sample of 215 family caregiver–patient dyads. Data were collected every 2 to 4 weeks over patients' last 6 months.

Results

Caregivers of patients in the worst symptom-functional states (States 3–5) reported worse subjective caregiving burden and depressive symptoms than those in the best two states, but the three outcomes did not differ between caregivers of patients in State 3 and States 4–5. Caregivers of patients in State 5 endured worse subjective caregiving burden and QOL than those in State 4. Caregivers of patients in State 4 suffered worse subjective caregiving burden and depressive symptoms but comparable QOL to those in State 2.

Conclusion

Patients' five distinct, conjoint symptom-functional states were significantly and differentially associated with their caregivers' worse subjective caregiving burden, QOL, and depressive symptoms while caring for patients over their last 6 months.  相似文献   
4.
Abstract

The purpose of this study was to investigate the strength of the relationships between self-efficacy and (i) functional exercise capacity and (ii) physical activity in chronic obstructive pulmonary disease (COPD), and whether self-efficacy assessment type (i.e., COPD symptoms, exercise-task, exercise-barrier, general, falls) and physical activity assessment type (i.e., self-report vs. objective) are moderators. A systematic search of COPD and self-efficacy concepts was conducted using eight databases from inception to 23 January 2019. Studies were included if they provided correlation coefficients of the relationship between self-efficacy and functional exercise capacity or physical activity, were conducted in adults diagnosed with COPD, and were published in English-language journals. A total of 14 correlation coefficients were included in the self-efficacy and functional exercise capacity meta-analysis, and 16 in the self-efficacy and physical activity meta-analysis. Data were screened, reviewed, and extracted independently by two reviewers, with discrepancies resolved by a third reviewer. Stronger self-efficacy was associated with better functional exercise capacity (weighted r?=?0.38, 95%CI [0.25, 0.50]), and greater physical activity (weighted r?=?0.25, 95%CI [0.17, 0.34]). Exercise-task self-efficacy had the strongest relationship to functional exercise capacity (weighted r?=?0.64, 95% CI [0.51, 0.73]). For physical activity, the type of self-efficacy most strongly related was inconclusive. In COPD, self-efficacy has a relationship to functional exercise capacity and physical activity, the strength of which is influenced by the choice of self-efficacy measure. An understanding of these relationships will assist clinicians in selecting the self-efficacy measure most closely related to the outcome of interest.  相似文献   
5.
综述了C_(60)化学研究的进展。C_(60)的化学反应性的研究展现了一个广阔的新领域,并使C_(60)作为一种新型的功能基团引入高分子成为现实。这些进展为进一步深入研究C_(60)尤其是C_(60)的材料化提供了前提。  相似文献   
6.
Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD.  相似文献   
7.
Functional dyspepsia (FD) is a highly prevalent gastrointestinal disorder and has a complex pathophysiology. Impaired fundic relaxation in response to a meal is present in 40% of patients with FD. This review focuses on impaired gastric accommodation of the stomach as a pathophysiological mechanism and the possible therapeutic targets that can be derived from the current knowledge of the neuroregulation of the accommodation reflex. First the different means of gastric accommodation assessment are described and the relationship between symptoms and impaired gastric accommodation. The different therapeutic options are subsequently discussed in view of their molecular target, based on the different receptor subtypes involved in the accommodation reflex. Although impaired gastric accommodation is highly prevalent in dyspeptic patients and basic knowledge about the accommodation reflex enables to develop pathophysiologically targeted therapies, it is unlikely that therapies aimed at dysaccommodation of the stomach will lead to symptom relief in all dyspeptic patients. A major challenge is the development of methods that readily identify impaired accommodation in clinical practice.  相似文献   
8.
Objective Reduction ascending aortoplasty is an alternative procdure to the replacement of the ascending aorts in case of ascending aorta dilation. However,its applicabikity is still under debate.This retrospective study was designed to evaluuate the midterm follow-up of unsupported ascending reduction aortoplasty for of the ascending aorta in petients with aortic valve dis- ease.Methods From October ,1996 to April,2007, a total of 54 patients with aortic valve disease and dilatation of the ascending aorta underwent unsupported reduction aortoplasty in combination with aortic valve replacement at our institution The diameter of the ascending aorta was measyred before and early after sugery and then later between 13 and 96 menths [mean (23 ±16)months] posto- perativeiy using echocardiography.Results Two patients were dead with thean overall perioperative mortality rate was of 3.7%. The reduction aortoplasty decreased the diameter of the aorta from (45.77±6.02) mm p~eope~afive]y to (34.67 ~4.81) mm early after surgery (P<0.01). During follow-up, the diameter d aorta increased from (34.67±4.81) mm early after surgery to (37.65± 6.35) mm after a mean follow-up of (23±16) months (P<0.01), including the diameters are greater than > 45 mm within 5 pa- tients. Aortic stenosis and an early postoperative diameter greater than 40 mm m'e independent risk factors for redilatation. Conchusion Because of the unsatisfied midterm follow-up redilation of unsupported reduction aortoplasty for dilation of the ascending aorta with aortic valve disease, this group of patients needs continued intimate fallow-up or even reoperation. The patients of stenosis is the surtable indication for RAA, and it is necessary to reduce the diameter of aorta to be lees than 40 mm to prevent redilation.  相似文献   
9.
There is limited information regarding oral health status and other predictors of oral health‐related quality of life. An association between oral health status and perceived oral health‐related quality of life (OHQOL) might help clinicians motivate patients to prevent oral diseases and improve the outcome of some dental public health programs. This study evaluated the relationship between older persons' OHQOL and their functional dentition, caries, periodontal status, chronic diseases, and some demographic characteristics. A group of 733 low‐income elders (mean age 72.7 ISD=4.71, 55.6% women, 55.1% members of ethnic minority groups in the U.S. and Canada) enrolled in the TEETH clinical trial were interviewed and examined as part of their fifth annual visit for the trial. OHQOL was measured by the Geriatric Oral Health Assessment Index (GOHAI); oral health and occlusal status by clinical exams and the Eichner Index; and demographics via interviews. Elders who completed the four‐year assessment had an average of 21.5 teeth (SD=6.9). with 8.5 occluding pairs (SD=4.6), and 32% with occlusal contacts in all four occluding zones. Stepwise multiple regressions were conducted to predict total GOHAI and its subscores (Physical, Social, and Worry). Functional dentition was a less significant predictor than ethnicity and being foreign‐bom. These variables, together with gender, years since immigrating, number of carious roots, and periodontal status, could predict 32% of the variance in total GOHAI, 24% in Physical, 27% in Social, and 21 % in the Worry subscales. These findings suggest that functional dentition and caries influence older adults' OHQOL, but that ethnicity and immigrant status play a larger role.  相似文献   
10.
胫骨延长术是矫治小儿麻痹后遗症下肢短缩最常见的术式,但如何恢复或改善术后的功能,目前尚无一套系统的程序。本文作者根据自行设计的胫骨延长休后功能康复的临床观察,作较系统地介绍,并就该程序的合理性,进行了讨论与论证。  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