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   2604篇
  免费   160篇
  国内免费   50篇
耳鼻咽喉   28篇
儿科学   87篇
妇产科学   47篇
基础医学   198篇
口腔科学   40篇
临床医学   254篇
内科学   647篇
皮肤病学   30篇
神经病学   91篇
特种医学   35篇
外科学   403篇
综合类   211篇
预防医学   298篇
眼科学   49篇
药学   184篇
  3篇
中国医学   123篇
肿瘤学   86篇
  2023年   81篇
  2022年   280篇
  2021年   196篇
  2020年   194篇
  2019年   162篇
  2018年   173篇
  2017年   88篇
  2016年   93篇
  2015年   87篇
  2014年   178篇
  2013年   214篇
  2012年   94篇
  2011年   139篇
  2010年   96篇
  2009年   104篇
  2008年   93篇
  2007年   66篇
  2006年   58篇
  2005年   46篇
  2004年   29篇
  2003年   61篇
  2002年   24篇
  2001年   15篇
  2000年   15篇
  1999年   31篇
  1998年   16篇
  1997年   11篇
  1996年   3篇
  1995年   11篇
  1994年   3篇
  1992年   6篇
  1991年   4篇
  1990年   3篇
  1989年   4篇
  1988年   3篇
  1987年   4篇
  1986年   4篇
  1985年   15篇
  1984年   9篇
  1983年   13篇
  1982年   17篇
  1981年   14篇
  1980年   13篇
  1979年   10篇
  1978年   3篇
  1977年   5篇
  1976年   6篇
  1975年   3篇
  1974年   4篇
  1973年   3篇
排序方式: 共有2814条查询结果,搜索用时 12 毫秒
31.
The purpose of this paper is to evaluate the concept reflection as a process using a principle‐based method of analysis that acknowledges the philosophical premises of formal cognitive operations (experiencing, understanding, judging, and deciding) espoused by Bernard Lonergan. The aim is to understand how we think and process cognitively in reflection while developing consciousness in knowing. Using Lonergan's formal cognitive operations adds a philosophical perspective and structure to the concept. Fostering the enactment of reflection is a complex process, but it is vital for nursing science and disciplinary advancement.  相似文献   
32.

Objective

To evaluate the current evidence of the effectiveness of dry needling of myofascial trigger points (MTrPs) associated with low back pain (LBP).

Data Sources

PubMed, Ovid, EBSCO, ScienceDirect, Web of Science, Cochrane Library, CINAHL, and China National Knowledge Infrastructure databases were searched until January 2017.

Study Selection

Randomized controlled trials (RCTs) that used dry needling as the main treatment and included participants diagnosed with LBP with the presence of MTrPs were included.

Data Extraction

Two reviewers independently screened articles, scored methodologic quality, and extracted data. The primary outcomes were pain intensity and functional disability at postintervention and follow-up.

Data Synthesis

A total of 11 RCTs involving 802 patients were included in the meta-analysis. Results suggested that compared with other treatments, dry needling of MTrPs was more effective in alleviating the intensity of LBP (standardized mean difference [SMD], ?1.06; 95% confidence interval [CI], ?1.77 to ?0.36; P=.003) and functional disability (SMD, ?0.76; 95% CI, ?1.46 to ?0.06; P=.03); however, the significant effects of dry needling plus other treatments on pain intensity could be superior to dry needling alone for LBP at postintervention (SMD, 0.83; 95% CI, 0.55–1.11; P<.00001).

Conclusions

Moderate evidence showed that dry needling of MTrPs, especially if associated with other therapies, could be recommended to relieve the intensity of LBP at postintervention; however, the clinical superiority of dry needling in improving functional disability and its follow-up effects still remains unclear.  相似文献   
33.
National and institutional quality initiatives provide benchmarks for evaluating the effectiveness of medical care. However, the dramatic growth in the number and type of medical and organizational quality-improvement standards creates a challenge to identify and understand those that most accurately determine quality in cardiac surgery. It is important that surgeons have knowledge and insight into valid, useful indicators for comparison and improvement. We therefore reviewed the medical literature and have identified improvement initiatives focused on cardiac surgery. We discuss the benefits and drawbacks of existing methodologies, such as comprehensive regional and national databases that aid self-evaluation and feedback, volume-based standards as structural indicators, process measurements arising from evidence-based research, and risk-adjusted outcomes. In addition, we discuss the potential of newer methods, such as patient-reported outcomes and composite measurements that combine data from multiple sources.  相似文献   
34.
This study extends the use of two lathyrogens, β-aminopropionitrile (BAPN) and D-penicillamine (DPA) from daily systemic or local-topical administration to long-time acting agents. This was achieved by converting the hydrophilic drugs into lipophilic derivatives. The synthesis of functional derivatives of DPA consisted in esterification with methyl-, hexyl-, or benzyl alcohols in the presence of thionylchloride. The esters formed were hydrochlorides, acidic and soluble in water. During neutralization in vitro or in vivo by tissue fluid, an oily substance is formed that elutes from a hydrogel polymer at a much slower rate than hydroplilic DPA itself. The degree of lipophilicity, measured as a partition coefficient between octanol/water, was highest for hexyl ester and lowest for methyl ester DPA. A single injection of either DPA hexyl ester HCl or 3-hexyl(amino) propionitrile into the full thickness skin incision wound in rats significantly lowered the breaking strength of the wound 12 days after injection, indicating the interference with collagen cross-linking. Both agents injected into the breast adenocarcinoma in Fisher rats significantly inhibited tumor growth without any signs of local or systemic toxicity. We conclude that these lipophilic lathyrogens with prolonged effectiveness are suitable in the treatment of pathologies, consisting of excessively cross-linked or deposited collagen (fibrotic adhesions, strictures, stenosis, and scar contractures) and in the treatment of single, solitary tumors, malignant and benign.  相似文献   
35.
Bibliometry is a quantitative statistical technique to measure levels of production and dissemination of knowledge, as well as a useful tool to track the development of an scientific area. The valuation of production required for recognition of researchers and magazines is accomplished through tools called bibliometricindexes, divided into quality indicators and scientific impact. Initially developed for monographs of statistical measures especially in libraries, today bibliometrics is mainly used to evaluate productivity of authors and citation repercussion. However, these tools have limitations and sometimes provoke controversies about indiscriminate application, leading to the development of newer indexes. It is important to know the most common search indexes and use it properly even acknowledging its limitations as it has a direct impact in their daily practice, reputation and funds achievement.  相似文献   
36.
37.

Background

Internet-based data collection relies on well-designed and validated questionnaires. The theory behind designing and validating questionnaires is well described, but few practical examples of how to approach validation are available in the literature.

Objective

We aimed to validate data collected in an ongoing Internet-based longitudinal health study through direct visits to participants and recall of their health records. We demonstrate that despite extensive pre-planning, social desirability can still affect data in unexpected ways and that anticipation of poor quality data may be confounded by positive validation.

Methods

Dogslife is a large-scale, Web-based longitudinal study of canine health, in which owners of Labrador Retrievers were recruited and questioned at regular intervals about the lifestyle and health of their dogs using an Internet-based questionnaire. The Dogslife questionnaire predominantly consists of closed-answer questions. In our work, two separate validation methodologies were used: (1) direct interviews with 43 participants during visits to their households and (2) comparison of owner-entered health reports with 139 historical health records.

Results

Our results indicate that user-derived measures should not be regarded as a single category; instead, each measurement should be considered separately as each presents its own challenge to participants. We recommend trying to ascertain the extent of recall decay within a study and, if necessary, using this to guide data collection timepoints and analyses. Finally, we recommend that multiple methods of communication facilitate validation studies and aid cohort engagement.

Conclusions

Our study highlighted how the theory underpinning online questionnaire design and validation translates into practical data issues when applied to Internet-based studies. Validation should be regarded as an extension of questionnaire design, and that validation work should commence as soon as sufficient data are available. We believe that validation is a crucial step and hope our suggested guidelines will help facilitate validation of other Internet-based cohort studies.  相似文献   
38.
39.
40.
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