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   3462篇
  免费   364篇
  国内免费   19篇
耳鼻咽喉   24篇
儿科学   161篇
妇产科学   71篇
基础医学   419篇
口腔科学   119篇
临床医学   335篇
内科学   637篇
皮肤病学   57篇
神经病学   364篇
特种医学   202篇
外科学   473篇
综合类   97篇
一般理论   3篇
预防医学   393篇
眼科学   97篇
药学   180篇
中国医学   3篇
肿瘤学   210篇
  2021年   46篇
  2020年   27篇
  2019年   59篇
  2018年   52篇
  2017年   69篇
  2016年   55篇
  2015年   70篇
  2014年   90篇
  2013年   120篇
  2012年   153篇
  2011年   153篇
  2010年   125篇
  2009年   135篇
  2008年   150篇
  2007年   195篇
  2006年   177篇
  2005年   173篇
  2004年   167篇
  2003年   147篇
  2002年   131篇
  2001年   79篇
  2000年   55篇
  1999年   71篇
  1998年   87篇
  1997年   76篇
  1996年   67篇
  1995年   53篇
  1994年   52篇
  1993年   45篇
  1992年   35篇
  1991年   41篇
  1990年   41篇
  1989年   56篇
  1988年   48篇
  1987年   57篇
  1986年   42篇
  1985年   38篇
  1984年   42篇
  1983年   37篇
  1982年   50篇
  1981年   40篇
  1980年   39篇
  1978年   24篇
  1977年   38篇
  1976年   30篇
  1975年   22篇
  1974年   34篇
  1973年   30篇
  1972年   27篇
  1970年   21篇
排序方式: 共有3845条查询结果,搜索用时 0 毫秒
91.
92.
Early Symptomatic Syndromes Eliciting Neurodevelopmental Examinations (ESSENCE) has been proposed as a guide to the neurodevelopmental needs of the under 5s. The problems are their multiplicity, the presence of partial features of specific conditions e.g. autism spectrum disorder and attention deficit/hyperactivity disorder and the young age of the children. For these reasons, child development teams often leave families to cope with very difficult situations. This paper includes epilepsy and the cerebral palsies to see if providing precise diagnostic categories and therapeutic targets can be achieved. It includes a discussion of causal sequences which have yet to be applied comprehensively to the neurodevelopment disorders.  相似文献   
93.
94.
95.

Introduction

Acute kidney injury (AKI) is a common but preventable cause of morbidity in elective arthroplasty patients. This study aimed to review the incidence and management of AKI in patients undergoing elective lower limb arthroplasty and compare results to those after the introduction of educational measures to improve prevention, recognition and management of AKI.

Methods

A retrospective case note review of all patients undergoing elective hip or knee arthroplasty between August and October 2013 was performed. Results were compared to patients treated from February to April 2014, after the introduction of a renal protection protocol, checklist poster and educational sessions. Results were statistically compared using Fisher’s exact test.

Results

Two hundred and eleven patients were included in the study: 104 in the initial cohort and 107 in the second cohort. Twenty patients (19.2 %) developed AKI in the initial cohort and 12 patients (11.2 %) in the second (p = 0.13). Recognition, documentation and management of AKI were significantly better following educational sessions and dissemination of posters throughout clinical areas, with 75 % of patients in the second cohort having their AKI documented and treated versus 30 % in the initial cohort.

Discussion/conclusions

This quality improvement project has demonstrated the significant impact that simple educational measures can have on improving AKI prevention, recognition and management in patients undergoing elective arthroplasty surgery. The introduction of a logical treatment checklist has been well received by both medical and nursing staff and ensures prompt and efficient management of AKI in a non-specialist area.
  相似文献   
96.
97.
Patients with premalignant oral lesions have varying levels of risk of developing oral squamous cell carcinoma (OSCC), whose aggressiveness requires increased motility. Not known is if and how premalignant oral lesion cells acquire the increased motility characteristic of OSCC. This was addressed by immunohistochemical analysis of banked premalignant lesion tissues and by functional analyses using cultures established from premalignant oral lesions and OSCC. These studies showed premalignant oral lesion cells and OSCC to be more motile than normal keratinocytes. Concomitantly, levels of ceramide were reduced. The activity of the protein phosphatase PP-2A, which restricts motility and which can be activated by ceramide, was also diminished. This was due to IL-10 released from premalignant lesion cells. Treatment with a membrane-permeable ceramide restored PP-2A activity and blocked migration. These studies show an autocrine motility-stimulatory pathway that is mediated in premalignant lesion cells by IL-10 through its reduction of ceramide levels and inhibition of PP-2A activity.  相似文献   
98.

Background

High volumes of sitting time are associated with an elevated risk of type 2 diabetes and cardiovascular disease, and with adverse cardiometabolic risk profiles. However, previous studies have predominately evaluated only total sitting or television (TV) viewing time, limiting inferences about the specific cardiometabolic health impacts of sitting accumulated in different contexts. We examined associations of sitting time in four contexts with cardiometabolic risk biomarkers in Australian adults.

Methods

Participants (n?=?3429; mean?±?SD age 58?±?10 years) were adults without clinically diagnosed diabetes or cardiovascular disease from the 2011–2012 Australian Diabetes, Obesity and Lifestyle (AusDiab) study. Multiple linear regressions examined associations of self-reported context-specific sitting time (occupational, transportation, TV-viewing and leisure-time computer use) with a clustered cardiometabolic risk score (CMR) and with individual cardiometabolic risk biomarkers (waist circumference, BMI, resting blood pressure, triglycerides, HDL- and LDL-cholesterol, and fasting and 2-h post-load plasma glucose).

Results

Higher CMR was significantly associated with greater TV-viewing and computer sitting time (b [95%CI]?=?0.07 [0.04, 0.09] and 0.06 [0.03, 0.09]), and tended to be associated with higher occupational and transport sitting time (0.01 [??0.01, 0.03] and 0.03 [??0.00, 0.06]), after adjustment for potential confounders. Furthermore, keeping total sitting time constant, accruing sitting via TV-viewing and computer use was associated with significantly higher CMR (0.05 [0.02, 0.08] and 0.04 [0.01, 0.06]), accruing sitting in an occupational context was associated with significantly lower CMR (??0.03 [??0.05, ??0.01]), while no significant association was seen for transport sitting (0.00 [??0.03, 0.04]). Results varied somewhat between the respective biomarkers; however, higher sitting time in each domain tended to be associated detrimentally with individual biomarkers except for fasting glucose (non-significant associations) and systolic blood pressure (a beneficial association was observed). Overall, associations were stronger for TV-viewing and computer use, and weaker for occupational sitting.

Conclusions

Higher context-specific sitting times tended to be detrimentally associated, albeit modestly, with CMR and several cardiometabolic risk biomarkers. There was some evidence suggesting that the context in which people sit is relevant above and beyond total sitting time. Methodological issues notwithstanding, these findings may assist in identifying priorities for sitting-reduction initiatives, in order to achieve optimal cardiometabolic health benefits.
  相似文献   
99.
100.

Background

Retinal vessel abnormalities are associated with cardiovascular disease risk. Widening of retinal venules is associated with increased risk of stroke while narrowing of retinal arterioles independently predicts incident hypertension, coronary heart disease and diabetes. Dietary factors are known to play an important role in cardiovascular health. However, few studies have examined the association between dietary patterns (DPs) and retinal microvascular health.

Objective

To examine the association between ‘a posteriori’- derived DPs and retinal vascular caliber (RVC) in older women with a restricted lifestyle.

Methods

This was a cross-sectional study of 1233 participants (mean age: 76.3 years) from the Irish Nun Eye Study (INES). Computer-assisted software was used to measure RVC from digital eye images using standardized protocols. Dietary intake was assessed using a food frequency questionnaire (FFQ). DP analysis was performed using principal component analysis from completed FFQs. Regression models were used to assess associations between DPs and retinal vessel diameters, adjusting for age, body mass index, refraction, hypertension, diabetes mellitus, ischemic heart disease, cerebrovascular accident and fellow eye RVC.

Results

Two DPs were identified: a ‘healthy’ pattern with high factor loadings for fruit, vegetables, wholegrains and oily fish and an ‘unhealthy’ pattern with high factor loadings for sugar and sweets, chips, high fat dairy products and French fries. Adjusted linear regression analysis revealed that those who adhered most closely to the unhealthy DP had wider central retinal venular equivalent (CRVE) (p=0.03) and narrower central retinal arteriolar equivalent (CRAE) (p=0.01) compared to the least unhealthy DP. No independent relationship was observed between the healthy DP and RVC.

Conclusion

In this cohort of older women with a restricted lifestyle, an unhealthy DP was independently associated with an unfavorable retinal profile, namely a widening of retinal venules and narrowing of retinal arterioles.
  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