全文获取类型
收费全文 | 2532篇 |
免费 | 204篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 52篇 |
妇产科学 | 38篇 |
基础医学 | 502篇 |
口腔科学 | 132篇 |
临床医学 | 274篇 |
内科学 | 385篇 |
皮肤病学 | 27篇 |
神经病学 | 281篇 |
特种医学 | 89篇 |
外科学 | 363篇 |
综合类 | 51篇 |
预防医学 | 193篇 |
眼科学 | 112篇 |
药学 | 115篇 |
中国医学 | 2篇 |
肿瘤学 | 87篇 |
出版年
2022年 | 26篇 |
2021年 | 48篇 |
2020年 | 23篇 |
2019年 | 36篇 |
2018年 | 38篇 |
2017年 | 32篇 |
2016年 | 38篇 |
2015年 | 29篇 |
2014年 | 52篇 |
2013年 | 70篇 |
2012年 | 86篇 |
2011年 | 88篇 |
2010年 | 53篇 |
2009年 | 44篇 |
2008年 | 88篇 |
2007年 | 83篇 |
2006年 | 82篇 |
2005年 | 90篇 |
2004年 | 66篇 |
2003年 | 96篇 |
2002年 | 94篇 |
2001年 | 62篇 |
2000年 | 73篇 |
1999年 | 70篇 |
1998年 | 32篇 |
1997年 | 22篇 |
1994年 | 24篇 |
1992年 | 63篇 |
1991年 | 59篇 |
1990年 | 65篇 |
1989年 | 56篇 |
1988年 | 64篇 |
1987年 | 56篇 |
1986年 | 64篇 |
1985年 | 75篇 |
1984年 | 46篇 |
1983年 | 48篇 |
1982年 | 22篇 |
1981年 | 28篇 |
1979年 | 42篇 |
1978年 | 32篇 |
1977年 | 28篇 |
1976年 | 26篇 |
1975年 | 33篇 |
1974年 | 36篇 |
1973年 | 30篇 |
1972年 | 28篇 |
1971年 | 19篇 |
1969年 | 19篇 |
1968年 | 19篇 |
排序方式: 共有2740条查询结果,搜索用时 15 毫秒
61.
62.
James J. Annesi Alice E. Smith Gisèle A. Tennant 《International journal of behavioral medicine》2013,20(4):562-566
Background
Inadequate volumes of physical activity may be associated with the increases in inappropriately high weight in children of 5 years of age and younger. Preschools have typically lacked sufficient time in daily physical activity.Purpose
A preschool-administered physical activity treatment based on social cognitive and self-efficacy theory (Start For Life) was tested for its association with increased physical activity and reduced body mass index (BMI).Methods
Data from accelerometer and BMI assessments over a 9-month preschool year (18 treatment and 8 control classes of 17 to 20 children each; mean age?=?4.4 years) were used to contrast the behaviorally based treatment of 30 min per day with a usual care condition of the same duration. The sample was primarily African-American. Preschool teachers administered all processes.Results
The Start For Life treatment was associated with a significantly greater percentage of the preschool day in moderate-to-vigorous and vigorous physical activity (approximately 30 min per week more), with sedentary time unaffected. The treatment was also associated with a significant reduction in BMI, with effect sizes greatest in overweight and obese children.Conclusions
Although results were positive in contrast to usual care and other related interventions, the specific sample requires that the Start For Life treatment undergo sufficient replication to increase confidence in generalizability of the findings to others. Although reduction in sedentary time may require a different strategy, the practical application of the present treatment suggests possibilities for addressing overweight through increasing moderate-to-vigorous physical activity in preschool settings. 相似文献63.
Rebecca E. Chandler 《Pharmacoepidemiology and drug safety》2020,29(8):951-957
64.
65.
66.
Berthiaume JM Young ME Chen X McElfresh TA Yu X Chandler MP 《Journal of molecular and cellular cardiology》2012,53(1):125-133
The normal heart relies primarily on the oxidation of fatty acids (FA) for ATP production, whereas during heart failure (HF) glucose utilization increases, implying pathological changes to cardiac energy metabolism. Despite the noted lipotoxic effects of elevating FA, our work has demonstrated a cardioprotective effect of a high fat diet (SAT) when fed after myocardial infarction (MI), as compared to normal chow (NC) fed cohorts. This data has suggested a mechanistic link to energy metabolism. The goal of this study was to determine the impact of SAT on the metabolic phenotype of the heart after MI. Male Wistar rats underwent coronary ligation surgery (MI) and were evaluated after 8 weeks of SAT. Induction of MI was verified by echocardiography. LV function assessed by in vivo hemodynamic measurements revealed improvements in the MI-SAT group as compared to MI-NC. Perfused working hearts revealed a decrease in cardiac work in MI-NC that was improved in MI-SAT. Glucose oxidation was increased and FA oxidation decreased in MI-NC compared to shams suggesting an alteration in the metabolic profile that was ameliorated by SAT. (31)P NMR analysis of Langendorff perfused hearts revealed no differences in PCr:ATP indicating no overt energy deficit in MI groups. Phospho-PDH and PDK(4) were increased in MI-SAT, consistent with a shift towards fatty acid oxidation (FAO). Overall, these results support the hypothesis that SAT post-infarction promotes a normal metabolic phenotype that may serve a cardioprotective role in the injured heart. 相似文献
67.
Chandler EM Seo BR Califano JP Andresen Eguiluz RC Lee JS Yoon CJ Tims DT Wang JX Cheng L Mohanan S Buckley MR Cohen I Nikitin AY Williams RM Gourdon D Reinhart-King CA Fischbach C 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(25):9786-9791
Multipotent adipose-derived stem cells (ASCs) are increasingly used for regenerative purposes such as soft tissue reconstruction following mastectomy; however, the ability of tumors to commandeer ASC functions to advance tumor progression is not well understood. Through the integration of physical sciences and oncology approaches we investigated the capability of tumor-derived chemical and mechanical cues to enhance ASC-mediated contributions to tumor stroma formation. Our results indicate that soluble factors from breast cancer cells inhibit adipogenic differentiation while increasing proliferation, proangiogenic factor secretion, and myofibroblastic differentiation of ASCs. This altered ASC phenotype led to varied extracellular matrix (ECM) deposition and contraction thereby enhancing tissue stiffness, a characteristic feature of breast tumors. Increased stiffness, in turn, facilitated changes in ASC behavior similar to those observed with tumor-derived chemical cues. Orthotopic mouse studies further confirmed the pathological relevance of ASCs in tumor progression and stiffness in vivo. In summary, altered ASC behavior can promote tumorigenesis and, thus, their implementation for regenerative therapy should be carefully considered in patients previously treated for cancer. 相似文献
68.
69.
Abstract A time series study of the Japanese suicide rate from 1970 to 1989 indicated that the establishment of suicide prevention centers may have been associated with a reduced suicide rate above and beyond the impact of social and economic factors. The effect was small and significant at only the 0.07 level, but sufficiently stable as to encourage further research to evaluate the effectiveness of suicide prevention centers. 相似文献
70.
Abstract Consumers who have a mental illness of a long term nature experience a range of difficulties which can impede their ability to lead satisfying and meaningful lives in the community. Treatment approaches need to emphasize personal recovery, integration, and rehabilitation to improve long term consumer outcomes. In Australia, there has been the opportunity to examine existing models of mental health care and develop new models, including rehabilitation. The focus in one mental health service has been on developing the skills and abilities of consumers, promoting their talents and achievements, and raising the profile of mental health. This paper describes the development of a psychiatric rehabilitation service where the emphasis has been on consumer and carer participation, collaboration in developing the service, and promoting community acceptance. 相似文献