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   1414篇
  免费   86篇
  国内免费   17篇
耳鼻咽喉   29篇
儿科学   38篇
妇产科学   19篇
基础医学   127篇
口腔科学   211篇
临床医学   128篇
内科学   297篇
皮肤病学   30篇
神经病学   71篇
特种医学   69篇
外科学   116篇
综合类   6篇
预防医学   160篇
眼科学   28篇
药学   121篇
中国医学   25篇
肿瘤学   42篇
  2023年   11篇
  2022年   43篇
  2021年   59篇
  2020年   46篇
  2019年   58篇
  2018年   60篇
  2017年   39篇
  2016年   49篇
  2015年   51篇
  2014年   71篇
  2013年   81篇
  2012年   121篇
  2011年   130篇
  2010年   53篇
  2009年   58篇
  2008年   81篇
  2007年   67篇
  2006年   56篇
  2005年   68篇
  2004年   51篇
  2003年   27篇
  2002年   36篇
  2001年   20篇
  2000年   25篇
  1999年   15篇
  1998年   16篇
  1997年   15篇
  1996年   6篇
  1995年   8篇
  1994年   4篇
  1993年   8篇
  1992年   7篇
  1991年   2篇
  1990年   5篇
  1989年   7篇
  1988年   6篇
  1987年   8篇
  1986年   8篇
  1985年   2篇
  1984年   7篇
  1983年   3篇
  1982年   7篇
  1981年   2篇
  1980年   5篇
  1977年   4篇
  1975年   2篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1961年   1篇
排序方式: 共有1517条查询结果,搜索用时 15 毫秒
51.
Several different plant extracts have been evaluated with respect to their antimicrobial effects against oral pathogens and for reduction of gingivitis. Given that a large number of these substances have been associated with significant side effects that contraindicate their long-term use, new compounds need to be tested. The aim of this study was to assess the short-term safety and efficacy of a Lippia sidoides ("alecrim pimenta")-based essential oil mouthrinse on gingival inflammation and bacterial plaque. Fifty-five patients were enrolled into a pilot, double-blinded, randomized, parallel-armed study. Patients were randomly assigned to undergo a 7-day treatment regimen with either the L. sidoides-based mouthrinse or 0.12% chlorhexidine mouthrinse. The results demonstrated decreased plaque index, gingival index and gingival bleeding index scores at 7 days, as compared to baseline. There was no statistically significance difference (p>0.05) between test and control groups for any of the clinical parameters assessed throughout the study. Adverse events were mild and transient. The findings of this study demonstrated that the L. sidoides-based mouthrinse was safe and efficacious in reducing bacterial plaque and gingival inflammation.  相似文献   
52.
Obesity Surgery - Evaluate the differences between surgical techniques in the modifications of body composition and the interference in skeletal muscle health, risk of sarcopenia, and reduced...  相似文献   
53.
The identification of idiopathic infertility cases, actually, is impossible. Among new functional tests, developed to improve the male fertility diagnosis, the evaluation of spermatic myo-inositol (MI) level, known as Andrositol® test (AT), is one of the most interesting, considering its weak economic burden and ease of use. The aim of this study was to evaluate the predictive power of AT and its potential use for a preliminary evaluation of semen samples. To evaluate the predictive power of AT, 87 sperm samples were analysed in comparison with spermiogram and sperm chromatin dispersion (SCD) Test, the gold standard analyses for male fertility evaluation. The application of AT resulted very useful for a preliminary sample evaluation, predicting the absence of DNA fragmentation in case of Low Responder samples precisely, and the presence of DNA fragmentation in case of medium or High Responder samples with abnormal morphology, predicting SCD results with a probability of 80% for Medium Responder sample and of 96.7% for High Responder sample. Considering the predictive power of this method, we could imagine, as preliminary qualitative analysis, its application before SCD test, deepening sperm analysis, improving the daily activities of laboratory operators and maintaining a good reliability of sperm evaluation.  相似文献   
54.

Objectives

The aim of the study was to compare total and regional body composition and their relationship with glucose homeostasis in physically active and non-active individuals with cervical spinal cord injury (c-SCI).

Methods

Individuals with lesion level between C5–C7 were divided into two groups: physically active (PA; n = 14; who practiced physical exercise for at least 3 months, three times per week or more, minimum of 150 minutes/week): and non-physically active (N-PA n = 8). Total fat mass (t-FM) and regional fat mass (r-FM) were assessed by dual energy X-ray absorptiometry. Fasting plasma insulin (FPI) was determined by enzyme-linked immunosorbent assay.

Results

PA group present lower (P < 0.01) total fat mass (t-FM), % and kg, regional fat mass (r-FM), % and kg, FPI levels and HOMA index, while they had higher (P < 0.001) total free fat mass (t-FFM), %, and regional free fat mass (r-FFM), %, compared to the N-PA group. In the N-PA group, FPI and HOMA index were negatively (P < 0.05) correlated with FFM% (r = −0.71, −0.69, respectively) and positively correlated to trunk-FM (r = 0.71, 0.69, respectively) and trunk-FM:t-FM (kg) ratio (r = 0.83, 0.79, respectively).

Conclusion

Physical exercise is associated with lower t-FM, r-FM, and insulin resistance, which could contribute to the decrease of the risk of cardiovascular and metabolic conditions in individuals with c-SCI.  相似文献   
55.
N-methyl-D-aspartate (NMDA) receptors are known to fulfill crucial functions in many forms of learning and plasticity. More recently, biophysical models, however, have suggested an additional role of NMDA receptors in evidence integration for decision-making, going beyond their role in learning. We designed a task to study the role of NMDA receptors in human reward-guided learning and decision-making. Human participants were assigned to receive either 250 mg of the partial NMDA agonist d-cycloserine (n=20) or matching placebo capsules (n=27). Reward-guided learning and decision-making were assessed using a task in which participants had to integrate learnt and explicitly shown value information to maximize their monetary wins and minimize their losses. To tease apart the effects of NMDA on learning and decision-making we used simple learning models. D-cycloserine shifted decision-making towards a more optimal integration of the learnt and the explicitly shown information, in the absence of a direct learning effect. In conclusion, our results reveal a distinct role for NMDA receptors in reward-guided decision-making. We discuss these findings in the context of NMDA''s roles in neuronal super-additivity and as crucial for evidence integration for decisions.  相似文献   
56.
57.
58.
BACKGROUND: There are widespread concerns regarding the quality of nursing home care and whether care is improving. We evaluated a large provider of nursing home care to determine whether risk-adjusted rates of pressure ulcer development have changed. METHODS: We used the Minimum Data Set to study National HealthCare Corporation nursing homes from 1991 through 1995. Rates of pressure ulcer development were calculated for successive 6-month periods by determining the proportion of residents initially ulcer-free having a stage 2 or larger pressure ulcer on subsequent assessments. Rates were risk-adjusted for patient characteristics. The proportion of new ulcers that were deep (stages 3 or 4) were also calculated. RESULTS: We examined risk-adjusted rates of pressure ulcer development based on 144,379 observations of 30,510 residents at 107 nursing homes. The number of observations per 6-month period ranged from 11,041 to 15,805. Between 1991 and 1995, there was a significant (P<.05) rate decline of more than 25%. Additionally, the proportion of new ulcers that were stages 3 or 4 declined from 30 to 22% (P<.01). CONCLUSIONS: Nursing homes showed significant improvement in the quality of pressure ulcer preventive care from 1991 to 1995.  相似文献   
59.
60.
Background:Good communication strategies are essential in times of crisis, such as the coronavirus pandemic. The dissemination of inaccurate information and the need for social isolation to control coronavirus disease 2019 (COVID-19) have shown a negative impact on the population, causing damage to mental health, with the appearance or worsening of symptoms of stress, fear, anxiety, and depression. Thus, the systematic review study is intended to gather evidence on the impact of information about COVID-19 on the mental health of the population.Methods:This systematic review protocol is conducted using the guidelines of the preferred reporting items for systematic reviews and meta-analyses protocols and the Cochrane Handbook for Systematic Reviews of Interventions. The review aims to include published studies that address the exposure of the general population to information about COVID-19, through observational and experimental studies, which consider the following outcomes: fear, stress, anxiety, and depression. Thus, a comprehensive research strategy will be conducted in the following databases: PubMed / Medline, Scopus, Web of Science, EMBASE, Science Direct, CINAHL, PsycINFO and Cochrane Central Register of Controlled Trials (CENTRAL). Two independent reviewers will perform all procedures, such as study selection, data collection, and methodological evaluation. Disagreements will be forwarded to a third reviewer. RevMan 5.3 software will be used for data analysis.Results:This systematic review will provide evidence of the influence of access to and consumption of media and scientific information about COVID-19 on the mental health of the population. It will consider information about the characterization of the study and the population studied, clinical and epidemiological information on mental health, and data on access to and consumption of media and scientific information.Discussion:The results should inform about the consequences of communication about the new coronavirus on the emergence or worsening of psychological and psychiatric symptoms, allowing to develop strategies to achieve effective communication of information to promote the mental health of the population.Systematic review registration number:PROSPERO CRD42020182918  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