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   30920篇
  免费   2560篇
  国内免费   668篇
耳鼻咽喉   238篇
儿科学   1278篇
妇产科学   779篇
基础医学   1745篇
口腔科学   907篇
临床医学   3630篇
内科学   6366篇
皮肤病学   405篇
神经病学   1337篇
特种医学   776篇
外国民族医学   1篇
外科学   2910篇
综合类   4198篇
现状与发展   1篇
预防医学   4568篇
眼科学   325篇
药学   2252篇
  36篇
中国医学   1154篇
肿瘤学   1242篇
  2024年   94篇
  2023年   840篇
  2022年   1359篇
  2021年   2173篇
  2020年   1858篇
  2019年   1726篇
  2018年   1690篇
  2017年   1249篇
  2016年   1155篇
  2015年   1097篇
  2014年   2324篇
  2013年   2187篇
  2012年   1833篇
  2011年   1977篇
  2010年   1590篇
  2009年   1513篇
  2008年   1400篇
  2007年   1435篇
  2006年   1032篇
  2005年   938篇
  2004年   727篇
  2003年   609篇
  2002年   417篇
  2001年   400篇
  2000年   279篇
  1999年   269篇
  1998年   214篇
  1997年   204篇
  1996年   173篇
  1995年   172篇
  1994年   158篇
  1993年   124篇
  1992年   134篇
  1991年   116篇
  1990年   89篇
  1989年   80篇
  1988年   55篇
  1987年   63篇
  1986年   47篇
  1985年   58篇
  1984年   57篇
  1983年   42篇
  1982年   40篇
  1981年   33篇
  1980年   29篇
  1979年   17篇
  1978年   22篇
  1977年   14篇
  1976年   15篇
  1975年   6篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
31.
AimsTo explore the association between WWI and the incidence of HTN in the Rural Chinese Cohort Study.Methods and ResultsWe examined data for 10,338 non-hypertensive participants (39.49% men) aged ≥ 18 years from the Rural Chinese Cohort Study who completed a baseline examination during 2007–2008 and follow-up during 2013–2014. WWI was calculated as waist circumference (cm) divided by the square root of weight (kg). Multiple logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the probability of HTN across four WWI categories. Restricted cubic splines analysis was used to model the dose–response association of WWI and HTN. A total of 2078 participants had HTN during a median follow-up of 6 years. After adjusting for potential confounders, as compared with the lowest WWI category (<9.94 cm/√kg), with WWI 9.94 to 10.42, 10.42 to 10.91 and ≥ 10.91 cm/√kg, the ORs (95% CIs) for HTN were 1.12 (0.93–1.35), 1.40 (1.17–1.69) and 1.50 (1.24–1.82), respectively. Results of the sensitivity analyses were robust. The ORs were generally consistent on subgroup analysis by sex, smoking status, systolic blood pressure and diastolic blood pressure. Multiple logistic regression models with restricted cubic splines showed a non-linear positive association between WWI and HTN (Pnonlinearity < 0.001).ConclusionThe highest WWI category was significantly associated with increased risk of HTN. Our findings may facilitate the development and promotion of obesity prevention strategies aimed at reducing the risk of HTN and provide evidence for healthcare policy in rural China.  相似文献   
32.
33.
34.
Women with pre-eclampsia have an increased risk of cardiovascular disease later in life. The aim of the study was to establish the presence and pattern of arterial stiffness in women previously with pre-eclampsia from a semi-rural region of South Africa. This was a prospective longitudinal study which involved 36 previously pre-eclamptic women and 86 non-pregnant controls (NPC) who had a past history of non-complicated pregnancy. Maternal wave reflection (augmentation index) and carotid-femoral pulse wave velocity were assessed noninvasively, using applanation tonometry with the SphygmoCor device. Endothelial function was assessed by EndoPAT 2000 device; pneumatic probes were fitted to the index fingers; induced flow-mediated reactive hyperemia; the ratio of the readings before and after occlusion was then used to calculate the score, the reactive hyperemia index (RHI) as a measure of endothelial function.

Pulse wave velocity remained significantly higher in previously pre-eclamptic women than non-pregnant controls up to three months after delivery (p < 0.05), then it reduced to nonsignificant values. All blood pressure indices (central and brachial pressures), were higher in previously pre-eclamptic women as compared to nonpregnant controls up to one year postpartum.

Regional (aortic) arterial stiffness, though it persists for some time after delivery, is transitory in previously pre-eclamptic women from the rural Africa setting. However, their increase blood pressure is an indication of compromised arterial compliance in women previously with pre-eclampsia.  相似文献   

35.
36.
ObjectivesVitamin D deficiency is prevalent among older adults. We aimed to study whether residential greenness could alter serum 25(OH)D concentrations as a possible mechanism of residential greenness's positive health effects.DesignA longitudinal cohort study.Setting and ParticipantsWe included older adults aged ≥65 years from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) with follow-up between 2012 and 2014.MethodsWe measured residential greenness by calculating annual average Normalized Difference Vegetation Index (NDVI) in a 500 m radius by using satellite images around each participant's residential address. Serum 25-hydroxyvitamin D (25(OH)D) concentration was dichotomized into 2 categories: nondeficiency (≥50 nmol/L) and deficiency (<50 nmol/L). We used the generalized estimating equation to examine the relationship between annual average NDVI and serum 25(OH)D.ResultsWe included 1336 participants in our analysis. The annual average NDVI was 0.49, and mean serum 25(OH)D was 43 nmol/L at baseline. Each 0.1-unit increase in annual average NDVI was associated with a 13% higher odds of vitamin D nondeficiency [95% confidence interval (CI): 1.01, 1.26]. The association was stronger among men [odds ratio (OR): 1.17, 95% CI: 1.02, 1.35] than women (OR: 1.08, 95% CI: 0.91, 1.29) and also stronger among those who were free of activities of daily living (ADL) disability at baseline (OR: 1.12, 95% CI: 1.00, 1.25). During the follow-up period, the participants who lived in greener areas were more likely to have an improved, rather than stable or deteriorated, vitamin D status (OR: 1.94, 95% CI: 1.51, 2.51).Conclusions and ImplicationsOur study suggests that higher levels of residential greenness are associated with higher serum 25(OH)D concentrations, which has implications for prevention of vitamin D deficiency among older adults.  相似文献   
37.
医学生的责任心体现在其一定行为表现上,是医学生职业精神培养的重要内涵,因此对影响医学生责任心的负向行为进行一定的干预具有重要意义。分析国内外医学院校应用责任指数考核在医学生行为督导养成的评价研究,遵循我国口腔医学专业人才培养的规律,结合口腔医学生成长的特点,借鉴职业精神考核的相关指标——责任指数考核法,试设计口腔医学生行为责任指数测评方案,并预设可行性,为拓宽口腔医学生职业精神的培养提供思路。  相似文献   
38.

Background

Acute myocardial infarction (AMI) causes irreversible myocardial damage and release of inflammatory mediators, including cytokines, chemokines and miRNAs. We aimed to investigate changes in the levels of cytokines (IL-6, TNF-α and IL-10), miRNAs profiles (miR-146 and miR-155) and distribution of different monocyte subsets (CD14++CD16-, CD14++CD16+, CD14+CD16++) in the acute and post-healing phases of AMI.

Methods

In eighteen consecutive AMI patients (mean age 56.78?±?12.4 years, mean left ventricle ejection fraction – LVEF: 41.9?±?9.8%), treated invasively, monocyte subsets frequencies were evaluated (flow cytometry), cytokine concentrations were analyzed (ELISA) as well as plasma miRNAs were isolated twice – on admission and after 19.2?±?5.9 weeks of follow-up. Measurements were also performed among healthy volunteers.

Results

AMI patients presented significantly decreased frequencies of classical cells in comparison to healthy controls (median 71.22% [IQR: 64.4–79.04] vs. 84.35% [IQR: 81.2–86.7], p?=?0.001) and higher percent of both intermediate and non-classical cells, yet without statistical significance (median 6.54% [IQR: 5.14–16.64] vs. 5.87% [IQR: 4.48–8.6], p?=?0.37 and median 5.99% [IQR: 3.39–11.5] vs. 5.26% [IQR: 3.62–6.2], p?=?0.42, respectively). In AMI patients both, analyzed plasma miRNA concentrations were higher than in healthy subjects (miR-146: median 5.48 [IQR: 2.4–11.27] vs. 1.84 [IQR: 0.87–2.53], p?=?0.003; miR-155: median 25.35 [IQR: 8.17–43.15] vs. 8.4 [IQR: 0.08–16.9], p?=?0.027, respectively), and returned back to the values found in the control group in follow-up. miR-155/miR-146 ratio correlated with the frequencies of classical monocytes (r=0.6, p?=?0.01) and miR-155 correlated positively with the concentration of inflammatory cytokines ? IL-6 and TNF-α.

Conclusions

These results may suggest cooperation of both pro-inflammatory and anti-inflammatory signals in AMI in order to promote appropriate healing of the infarcted myocardium.  相似文献   
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