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   2379篇
  免费   235篇
  国内免费   27篇
耳鼻咽喉   30篇
儿科学   11篇
妇产科学   10篇
基础医学   497篇
口腔科学   64篇
临床医学   386篇
内科学   227篇
皮肤病学   13篇
神经病学   418篇
特种医学   68篇
外科学   299篇
综合类   157篇
一般理论   3篇
预防医学   223篇
眼科学   29篇
药学   128篇
  8篇
中国医学   27篇
肿瘤学   43篇
  2023年   44篇
  2022年   51篇
  2021年   89篇
  2020年   113篇
  2019年   98篇
  2018年   110篇
  2017年   99篇
  2016年   78篇
  2015年   114篇
  2014年   137篇
  2013年   195篇
  2012年   99篇
  2011年   99篇
  2010年   86篇
  2009年   113篇
  2008年   127篇
  2007年   82篇
  2006年   88篇
  2005年   74篇
  2004年   43篇
  2003年   63篇
  2002年   36篇
  2001年   32篇
  2000年   42篇
  1999年   33篇
  1998年   31篇
  1997年   35篇
  1996年   31篇
  1995年   28篇
  1994年   26篇
  1993年   22篇
  1992年   40篇
  1991年   21篇
  1990年   17篇
  1989年   17篇
  1988年   14篇
  1987年   18篇
  1986年   19篇
  1985年   22篇
  1984年   23篇
  1983年   13篇
  1982年   14篇
  1981年   10篇
  1980年   15篇
  1979年   13篇
  1978年   16篇
  1977年   7篇
  1976年   13篇
  1975年   6篇
  1972年   5篇
排序方式: 共有2641条查询结果,搜索用时 25 毫秒
91.

Background

Web-based, computer-tailored nutrition education interventions can be effective in modifying self-reported dietary behaviors. Traditional computer-tailored programs primarily targeted individual cognitions (knowledge, awareness, attitude, self-efficacy). Tailoring on additional variables such as self-regulation processes and environmental-level factors (the home food environment arrangement and perception of availability and prices of healthy food products in supermarkets) may improve efficacy and effect sizes (ES) of Web-based computer-tailored nutrition education interventions.

Objective

This study evaluated the short- and medium-term efficacy and educational differences in efficacy of a cognitive and environmental feedback version of a Web-based computer-tailored nutrition education intervention on self-reported fruit, vegetable, high-energy snack, and saturated fat intake compared to generic nutrition information in the total sample and among participants who did not comply with dietary guidelines (the risk groups).

Methods

A randomized controlled trial was conducted with a basic (tailored intervention targeting individual cognition and self-regulation processes; n=456), plus (basic intervention additionally targeting environmental-level factors; n=459), and control (generic nutrition information; n=434) group. Participants were recruited from the general population and randomly assigned to a study group. Self-reported fruit, vegetable, high-energy snack, and saturated fat intake were assessed at baseline and at 1- (T1) and 4-months (T2) postintervention using online questionnaires. Linear mixed model analyses examined group differences in change over time. Educational differences were examined with group×time×education interaction terms.

Results

In the total sample, the basic (T1: ES=–0.30; T2: ES=–0.18) and plus intervention groups (T1: ES=–0.29; T2: ES=–0.27) had larger decreases in high-energy snack intake than the control group. The basic version resulted in a larger decrease in saturated fat intake than the control intervention (T1: ES=–0.19; T2: ES=–0.17). In the risk groups, the basic version caused larger decreases in fat (T1: ES=–0.28; T2: ES=–0.28) and high-energy snack intake (T1: ES=–0.34; T2: ES=–0.20) than the control intervention. The plus version resulted in a larger increase in fruit (T1: ES=0.25; T2: ES=0.37) and a larger decrease in high-energy snack intake (T1: ES=–0.38; T2: ES=–0.32) than the control intervention. For high-energy snack intake, educational differences were found. Stratified analyses showed that the plus version was most effective for high-educated participants.

Conclusions

Both intervention versions were more effective in improving some of the self-reported dietary behaviors than generic nutrition information, especially in the risk groups, among both higher- and lower-educated participants. For fruit intake, only the plus version was more effective than providing generic nutrition information. Although feasible, incorporating environmental-level information is time-consuming. Therefore, the basic version may be more feasible for further implementation, although inclusion of feedback on the arrangement of the home food environment and on availability and prices may be considered for fruit and, for high-educated people, for high-energy snack intake.

Trial Registration

Netherlands Trial Registry NTR3396; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3396 (Archived by WebCite at http://www.webcitation.org/6VNZbdL6w).  相似文献   
92.
93.
Providing formative assessment opportunities has been recognised as a significant benefit to student learning. The outcome of any formative assessment should be one that ultimately helps improve student learning through familiarising students with the levels of learning required, informing them about gaps in their learning and providing feedback to guide the direction of learning. This article provides an example of how formative assessments can be developed into a formative assessment journey where a number of different assessments can be offered to students during the course of a module of teaching, thus utilising a spaced-education approach. As well as incorporating the specific drivers of formative assessment, we demonstrate how approaches deemed to be stimulating, interactive and entertaining with the aim of maximising enthusiasm and engagement can be incorporated. We provide an example of a mixed approach to evaluating elements of the assessment journey that focuses student reaction, appraisal of qualitative and quantitative feedback from student questionnaires, focus group analysis and teacher observations. Whilst it is not possible to determine a quantifiable effect of the assessment journey on student learning, usage data and student feedback shows that formative assessment can achieve high engagement and positive response to different assessments. Those assessments incorporating an active learning element and a quiz-based approach appear to be particularly popular. A spaced-education format encourages a building block approach to learning that is continuous in nature rather than focussed on an intense period of study prior to summative examinations.  相似文献   
94.
目的:探讨益髓醒神针刺联合镜像视觉反馈(MVF)治疗脑卒中后单侧空间忽略(USN)的康复情况。方法:以2016年6月-2018年12月杭州市中医院康复科脑卒中后左脑偏瘫的患者为研究对象,采用随机数字表法分为两组。对照组(38例)进行镜像视觉反馈(MVF)训练联合常规治疗与康复训练,干预组(39例)在对照组基础上加用益髓醒神针刺治疗,均治疗4周。通过对比两组治疗前及4周后SUN程度、肢体运动功能、日常生活能力、认知功能,焦虑、抑郁情绪,以及生活质量评估患者康复效果。结果:两组一般资料差异均无统计学意义(均P>0.05)。经过4周治疗后,与治疗前相比,两组患者USN程度均出现明显下降(P<0.01);肢体运动功能、日常生活能力和精神认知功能均明显提高(P<0.01);焦虑、抑郁情绪得到缓解(P<0.01);生活质量得到提高(P<0.05)。并且两组比较,研究组在SUN程度、肢体运动功能、日常生活能力、认知功能,负性情绪各方面均进一步得到改善(P<0.05);生活质量方面在生理机能、生理职能、精力、社会功能及一般健康维度评分上提高更加明显(P<0.05)。结论:益髓醒神针联合MVF对卒中后USN患者具有协同康复作用,可提高患者USN、肢体运动功能、日常生活能力、精神认知,改善患者负性情绪,提高生活质量,值得临床进一步推广。  相似文献   
95.
Photosynthetic organisms avoid photodamage to photosystem II (PSII) in variable light conditions via a suite of photoprotective mechanisms called nonphotochemical quenching (NPQ), in which excess absorbed light is dissipated harmlessly. To quantify the contributions of different quenching mechanisms to NPQ, we have devised a technique to measure the changes in chlorophyll fluorescence lifetime as photosynthetic organisms adapt to varying light conditions. We applied this technique to measure the fluorescence lifetimes responsible for the predominant, rapidly reversible component of NPQ, qE, in living cells of Chlamydomonas reinhardtii. Application of high light to dark-adapted cells of C. reinhardtii led to an increase in the amplitudes of 65 ps and 305 ps chlorophyll fluorescence lifetime components that was reversed after the high light was turned off. Removal of the pH gradient across the thylakoid membrane linked the changes in the amplitudes of the two components to qE quenching. The rise times of the amplitudes of the two components were significantly different, suggesting that the changes are due to two different qE mechanisms. We tentatively suggest that the changes in the 65 ps component are due to charge-transfer quenching in the minor light-harvesting complexes and that the changes in the 305 ps component are due to aggregated light-harvesting complex II trimers that have detached from PSII. We anticipate that this technique will be useful for resolving the various mechanisms of NPQ and for quantifying the timescales associated with these mechanisms.  相似文献   
96.
The boreal forests, identified as a critical "tipping element" of the Earth's climate system, play a critical role in the global carbon budget. Recent findings have suggested that terrestrial carbon sinks in northern high-latitude regions are weakening, but there has been little observational evidence to support the idea of a reduction of carbon sinks in northern terrestrial ecosystems. Here, we estimated changes in the biomass carbon sink of natural stands throughout Canada's boreal forests using data from long-term forest permanent sampling plots. We found that in recent decades, the rate of biomass change decreased significantly in western Canada (Alberta, Saskatchewan, and Manitoba), but there was no significant trend for eastern Canada (Ontario and Quebec). Our results revealed that recent climate change, and especially drought-induced water stress, is the dominant cause of the observed reduction in the biomass carbon sink, suggesting that western Canada's boreal forests may become net carbon sources if the climate change-induced droughts continue to intensify.  相似文献   
97.
Objective: Rehabilitation of upper-limb sensorimotor function in children with motor dysfunctions is primarily based on movement training. This study developed a virtual-reality based, paediatric interactive therapy system (PITS) that allows children to practice specific movements of the upper limbs with immediate feedback about their motor performance.

Methods: The system was tested on five children with motor dysfunctions over 3 weeks of training. Pre- and post-assessment was conducted before and after the training period.

Results: Results of the pilot study show improvements of hand function in the test scores (except one patient). Patient motivation was high and maintained over the course of the therapy sessions.

Conclusion: PITS is an applicable VR-system which can be feasibly applied during the rehabilitation of children with upper limb motor dysfunctions. Further investigation is necessary to determine if the system provides significantly improved results compared to conventional therapies, both in terms of motor function outcomes and patient motivation.  相似文献   
98.
Treatment with a mirror gives an illusion of function in a missing or non-functioning hand. The method is based on the concept that the central representation of phantoms and body image can change rapidly, and has been described in the treatment of phantom pain and stroke. We show in three pilot cases new applications for the use of the mirror in rehabilitation after hand surgery.  相似文献   
99.
Ultrasound has shown promise as a visual feedback tool in speech therapy. Rural clients, however, often have minimal access to new technologies. The purpose of the current study was to evaluate consultative treatment using ultrasound in rural communities. Two speech‐language pathologists (SLPs) trained in ultrasound use provided consultation with ultrasound in rural British Columbia to 13 school‐aged children with residual speech impairments. Local SLPs provided treatment without ultrasound before and after the consultation. Speech samples were transcribed phonetically by independent trained listeners. Eleven children showed greater gains in production of the principal target // after the ultrasound consultation. Four of the seven participants who received more consultation time with ultrasound showed greatest improvement. Individual client factors also affected outcomes. The current study was a quasi‐experimental clinic‐based study. Larger, controlled experimental studies are needed to provide ultimate evaluation of the consultative use of ultrasound in speech therapy.  相似文献   
100.
We have developed a feedback-controlled bolus plus infusion (FC-B/I) method for monitoring the interaction between positron emission tomography (PET) ligands and their specific target molecules with PET. The usefulness of the FC-B/I method was evaluated by the direct interaction between [11C]raclopride, a dopamine D2 receptor (D2R) ligand, and cold raclopride (10 and 100 μg/kg) in the brains of conscious monkeys. The present results demonstrated that the FC-B/I method could achieve the equilibrium state of [11C]raclopride in the striatum of monkey brain, and also that the cold raclopride-induced reduction of [11C]raclopride binding to D2R was observed in a dose-dependent manner. Good correlations of distribution volume ratio of the striatum to cerebellum between the conventional bolus plus infusion (B/I) method and the FC-B/I method as well as between the conventional bolus injection method and the FC-B/I method were observed. These results indicated that the system could be a useful tool for the evaluation of interaction between drug candidates and their target molecules like enzymes, receptors, and transporters by using of their specific PET ligands.  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