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   12206篇
  免费   756篇
  国内免费   46篇
耳鼻咽喉   190篇
儿科学   232篇
妇产科学   279篇
基础医学   1735篇
口腔科学   1456篇
临床医学   917篇
内科学   2527篇
皮肤病学   221篇
神经病学   1102篇
特种医学   281篇
外科学   1279篇
综合类   49篇
一般理论   4篇
预防医学   1146篇
眼科学   177篇
药学   775篇
中国医学   100篇
肿瘤学   538篇
  2023年   96篇
  2022年   222篇
  2021年   444篇
  2020年   311篇
  2019年   424篇
  2018年   484篇
  2017年   350篇
  2016年   382篇
  2015年   467篇
  2014年   547篇
  2013年   675篇
  2012年   1012篇
  2011年   1037篇
  2010年   550篇
  2009年   439篇
  2008年   675篇
  2007年   771篇
  2006年   628篇
  2005年   541篇
  2004年   465篇
  2003年   433篇
  2002年   343篇
  2001年   243篇
  2000年   209篇
  1999年   187篇
  1998年   69篇
  1997年   47篇
  1996年   35篇
  1995年   50篇
  1994年   36篇
  1993年   26篇
  1992年   76篇
  1991年   95篇
  1990年   78篇
  1989年   62篇
  1988年   45篇
  1987年   33篇
  1986年   35篇
  1985年   40篇
  1984年   26篇
  1983年   18篇
  1980年   19篇
  1979年   36篇
  1978年   19篇
  1976年   17篇
  1974年   16篇
  1973年   16篇
  1971年   18篇
  1970年   17篇
  1966年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Purpose of the study: the aim of this study was to synthesize PFC fNIRS outcomes on the effects of cognitive tasks compared to resting/baseline tasks in healthy adults from studies utilizing a pre/post design.

Material and methods: original research studies were searched from seven databases (MEDLINE, EMBASE, CENTRAL, CINAHL, SCOPUS, PEDro and PubMed). Subsequently, two independent reviewers screened the titles and abstracts followed by full-text reviews to assess the studies' eligibility.

Results: eleven studies met the inclusion criteria and had data abstracted and quality assessed. Methodology varied considerably and yet cognitive tasks resulted in the ΔO2Hb increasing in 8 of the 11 and ΔHHb decreasing in 8 of 8 studies that reported this outcome. The cognitive tasks from 10 of the 11 studies were classified as “Working Memory” and “Verbal Fluency Tasks”.

Conclusions: although, the data comparison was challenging provided the heterogeneity in methodology, the results across studies were similar.  相似文献   

5.
Background and aimsThe long-term relations between excessive adiposity in early childhood and unfavourable cardiometabolic profiles in later ages are not yet completely understood. We aimed to assess the associations between birth weight (BW) and BMI from 6 months to 6 years of age, with biomarkers indicative of low-grade inflammation, insulin resistance and lipid profiles in adolescence.Methods and resultsRetrospective school-based study with 415 Portuguese adolescents (220 girls), mean age of 14.08 ± 1.6 years old. Anthropometric data from birth to 6 years old was extracted from individual child health book records. Actual weight and height were measured and BMI calculated. Participants were classified at each time point as normal weight or overweight according to WHO reference values. Biomarkers were obtained from venous blood samples. Linear regressions were used to explore the associations between the biomarkers and early life anthropometric indicators. From 2 years onwards, BMI associated positively with the inflammatory score and HOMA-IR in adolescence. Children who were overweight/obese from 2 to 6 years of age presented significantly higher inflammatory score and HOMA-IR later in adolescence. TC/HDL ratio was also positively associated with BMI from the age of 5 years onwards. The associations between BMI and cardiometabolic outcomes remained positive in adolescence, with overweight adolescents presenting a higher inflammatory score, HOMA-IR and TC/HDL than normal weight adolescents.ConclusionA high BMI from an early age was consistently associated with worse inflammatory and lipid profiles and insulin resistance in adolescence. No associations were found between BW and the same studied outcomes.  相似文献   
6.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  相似文献   
7.

Background Drug-related problems are mostly preventable or predictable circumstances that may impact on health outcomes. Clinical pharmacy activities such as medication therapy management can identify and solve these problems, with potential to improve medication safety and effectiveness. Objective To evaluate ability of medication therapy management service to detect drug-related problems and prevent adverse drug events. This study also aimed to assess the risk factors for drugrelated problem occurrence. Setting Medical intensive care unit of a public tertiary hospital in Brazil. Methods Patients were evaluated by a clinical pharmacist, who provided medication therapy management service. Detected drug-related problems were categorized according to the Pharmaceutical Care Network Europe methodology and analyzed in multinomial regression to identify risk factors. Main outcome measure Potential risk factors for drug-related problem occurrence. Results The proposed medication therapy management service allowed detection of 170 drug-related problems that had potential to reach patients causing harm and other 50 unavoidable adverse events. Drug-related problems identified were more often associated with antibacterial use, caused by improper combinations or inadequate drug dosage. These problems required interventions that were accepted by the multidisciplinary team, resulting in more than 85% adherence and total problem solving. Main risk factors identified were previous diagnosis of kidney injury (OR?=?8.38), use of midazolam (OR?=?7.96), furosemide (OR?=?5.87) and vancomycin (OR?=?4.82). Conclusion Medication therapy management proved to be an effective method not only for drug-related problem detection, but also for adverse drug event prevention, contributing to improve patient safety.

  相似文献   
8.
Studies on the exposure of children to sugar-sweetened beverages (SSBs) at an early age may contribute to better understand the common causes and the temporal order of the relationships between obesity and asthma in early childhood. The objective of this study was to estimate the association between SSB and child asthma traits in the 2nd year of life, modeling direct and indirect pathways mediated by the highest BMI-z of the child and allergic inflammation. Data from the BRISA cohort, São Luís-MA, Brazil (n = 1140), were obtained from the baseline and from the follow-up performed at the 2nd year of life. The main explanatory variable was the calories from added sugars in SSBs as a percentage of the total daily energy intake. The outcome child asthma traits was a latent variable deduced from four indicators: medical diagnosis of asthma, wheezing, emergency visit due to intense wheezing, and medical diagnosis of rhinitis. A high percentage of daily calories from sugars added to SSBs was directly associated with higher values of child asthma traits (standardized coefficient (SC = 0.073; P = .030)). High levels of eosinophils were also directly associated with child asthma traits (SC = 0.118; P = .049). No mediation pathways were observed via greater BMI-z or eosinophil counts. Therefore, early exposure of children to SSB may contribute to increased risk of childhood asthma, preceding the link between sugar consumption and overweight/obesity, not yet evident in children in the first 2 years of life.  相似文献   
9.
10.
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