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   36755篇
  免费   2790篇
  国内免费   58篇
耳鼻咽喉   335篇
儿科学   1279篇
妇产科学   1045篇
基础医学   4922篇
口腔科学   499篇
临床医学   4732篇
内科学   6545篇
皮肤病学   559篇
神经病学   3808篇
特种医学   813篇
外国民族医学   4篇
外科学   3498篇
综合类   435篇
一般理论   48篇
预防医学   4902篇
眼科学   633篇
药学   2570篇
中国医学   26篇
肿瘤学   2950篇
  2023年   278篇
  2022年   449篇
  2021年   1172篇
  2020年   708篇
  2019年   1092篇
  2018年   1229篇
  2017年   883篇
  2016年   1023篇
  2015年   1080篇
  2014年   1416篇
  2013年   1990篇
  2012年   2926篇
  2011年   3145篇
  2010年   1661篇
  2009年   1398篇
  2008年   2538篇
  2007年   2552篇
  2006年   2321篇
  2005年   2182篇
  2004年   1985篇
  2003年   1710篇
  2002年   1719篇
  2001年   335篇
  2000年   286篇
  1999年   311篇
  1998年   378篇
  1997年   278篇
  1996年   199篇
  1995年   220篇
  1994年   169篇
  1993年   149篇
  1992年   164篇
  1991年   135篇
  1990年   134篇
  1989年   112篇
  1988年   124篇
  1987年   123篇
  1986年   109篇
  1985年   68篇
  1984年   74篇
  1983年   79篇
  1982年   53篇
  1981年   48篇
  1979年   57篇
  1978年   42篇
  1977年   32篇
  1975年   33篇
  1973年   34篇
  1972年   54篇
  1971年   41篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
11.
12.

Objectives

To investigate whether functional overreaching affects locomotor system behaviour when running at fixed relative intensities and if any effects were associated with changes in running performance.

Design

Prospective intervention study.

Methods

Ten trained male runners completed three training blocks in a fixed order. Training consisted of one week of light training (baseline), two weeks of heavy training designed to induce functional overreaching, and ten days of light taper training designed to allow athletes to recover from, and adapt to, the heavy training. Locomotor behaviour, 5-km time trial performance, and subjective reports of training status (Daily Analysis of Life Demands for Athletes (DALDA) questionnaire) were assessed at the completion of each training block. Locomotor behaviour was assessed using detrended fluctuation analysis of stride intervals during running at speeds corresponding to 65% and 85% of maximum heart rate (HRmax) at baseline.

Results

Time trial performance (effect size ±95% confidence interval (ES): 0.16 ± 0.06; p < 0.001), locomotor behaviour at 65% HRmax (ES: ?1.12 ± 0.95; p = 0.026), and DALDA (ES: 2.55 ± 0.80; p < 0.001) were all detrimentally affected by the heavy training. Time trial performance improved relative to baseline after the taper (ES: ?0.16 ± 0.10; p = 0.003) but locomotor behaviour at 65% HRmax (ES: ?1.18 ± 1.17; p = 0.048) and DALDA (ES: 0.92 ± 0.90; p = 0.045) remained impaired.

Conclusions

Locomotor behaviour during running at 65% HRmax was impaired by functional overreaching and remained impaired after a 10-day taper, despite improved running performance. Locomotor changes may increase injury risk and should be considered within athlete monitoring programs independently of performance changes.  相似文献   
13.
14.
Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619).  相似文献   
15.
16.
ABSTRACT

Abortion is legal in South Africa, but negative abortion attitudes remain common and are poorly understood. We used nationally representative South African Social Attitudes Survey data to analyze abortion attitudes in the case of fetal anomaly and in the case of poverty from 2007 to 2016 (n = 20,711; ages = 16+). We measured correlations between abortion attitudes and these important predictors: religiosity, attitudes about premarital sex, attitudes about preferential hiring and promotion of women, and attitudes toward family gender roles. Abortion acceptability for poverty increased over time (b = 0.05, p < .001), but not for fetal anomaly (b = ?0.008, p = .284). Highly religious South Africans reported lower abortion acceptability in both cases (Odds Ratio (OR)anomaly = 0.85, p = .015; ORpoverty = 0.84, p = .02). Premarital sex acceptability strongly and positively predicted abortion acceptability (ORanomaly = 2.63, p < .001; ORpoverty = 2.46, p < .001). Attitudes about preferential hiring and promotion of women were not associated with abortion attitudes, but favorable attitudes about working mothers were positively associated with abortion acceptability for fetal anomaly ((ORanomaly = 1.09, p = .01; ORpoverty = 1.02, p = .641)). Results suggest negative abortion attitudes remain common in South Africa and are closely tied to religiosity, traditional ideologies about sexuality, and gender role expectations about motherhood.  相似文献   
17.
The normal function of the hypothalamic-pituitary-adrenal (HPA) axis, and resultant glucocorticoid (GC) secretion, is essential for human health. Disruption of GC regulation is associated with pathologic, psychological, and physiological disease states such as depression, post-traumatic stress disorder, hypertension, diabetes, and osteopenia, among others. As such, understanding the mechanisms by which HPA output is tightly regulated in its responses to environmental stressors and circadian cues has been an active area of investigation for decades. Over the last 20 years, however, advances in gene targeting and genome modification in rodent models have allowed the detailed dissection of roles for key molecular mediators and brain regions responsible for this control in vivo to emerge. Here, we summarize work done to elucidate the function of critical neuropeptide systems, GC-signaling targets, and inflammation-associated pathways in HPA axis regulation and behavior, and highlight areas for future investigation.  相似文献   
18.
19.
20.

Background

One approach to boost influenza vaccination coverage has been to expand immunization authority. In 2012, the province of Ontario gave community pharmacists the authority to administer the influenza vaccine.

Objective

This study investigates the perspectives of Ontario pharmacy patrons, who had not recently received this vaccine from a pharmacist, regarding this pharmacist service.

Methods

A survey was administered in six Ontario community pharmacies to pharmacy patrons who had not received an influenza vaccination from a pharmacist during the previous year. The instrument included questions about influenza vaccination, and knowledge of and attitudes toward vaccines and pharmacist-administered immunization.

Results

A total of 541 pharmacy patrons completed the survey (53.9% response rate). About one-third (30.5%) of respondents were not aware that pharmacists could give the influenza vaccine, with younger individuals being less likely to be aware (OR 0.48, 95% CI 0.29–0.77, p?<?0.05) and less likely to receive the vaccine annually (OR 0.28, 95% CI 0.19–0.42, p?<?0.05). Leading reasons respondents gave as to why they did not receive their influenza vaccine from a pharmacist included not wanting or feeling they needed to be immunized (41.6%) and being used to receiving the vaccine from a physician (16.5%). Concerns about the experience and training of pharmacists and lack of privacy in a community pharmacy were uncommon.

Conclusion

Reduced awareness of the availability of pharmacist-provided influenza vaccine is still common. Pharmacists have a significant opportunity to address lack of awareness and vaccine hesitancy issues. They can promote this service to increase influenza vaccination rates among pharmacy patrons who do not utilize this professional service.  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