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   3517篇
  免费   306篇
  国内免费   61篇
耳鼻咽喉   120篇
儿科学   65篇
妇产科学   70篇
基础医学   455篇
口腔科学   89篇
临床医学   304篇
内科学   584篇
皮肤病学   76篇
神经病学   242篇
特种医学   271篇
外科学   637篇
综合类   146篇
一般理论   2篇
预防医学   161篇
眼科学   94篇
药学   257篇
中国医学   29篇
肿瘤学   282篇
  2023年   20篇
  2022年   47篇
  2021年   118篇
  2020年   66篇
  2019年   72篇
  2018年   96篇
  2017年   77篇
  2016年   121篇
  2015年   123篇
  2014年   120篇
  2013年   184篇
  2012年   242篇
  2011年   233篇
  2010年   155篇
  2009年   144篇
  2008年   171篇
  2007年   207篇
  2006年   172篇
  2005年   178篇
  2004年   168篇
  2003年   127篇
  2002年   111篇
  2001年   96篇
  2000年   105篇
  1999年   89篇
  1998年   61篇
  1997年   56篇
  1996年   38篇
  1995年   35篇
  1994年   25篇
  1993年   25篇
  1992年   30篇
  1991年   25篇
  1990年   36篇
  1989年   49篇
  1988年   40篇
  1987年   31篇
  1986年   25篇
  1985年   22篇
  1984年   20篇
  1983年   13篇
  1982年   8篇
  1981年   13篇
  1980年   12篇
  1979年   8篇
  1978年   8篇
  1977年   10篇
  1976年   7篇
  1975年   7篇
  1968年   6篇
排序方式: 共有3884条查询结果,搜索用时 15 毫秒
71.
The control of plasma glucose needs to be tightly monitored because hyperglycaemia and hypoglycaemia can lead to severe clinical problems, including death. In this article the major mechanism for the transport of glucose into and out of the blood and how that mechanism is used to monitor the circulating concentrations of glucose are discussed. A number of hormones regulate glucose in response to changes in plasma concentrations. Insulin promotes the removal of glucose and its conversion to glycogen. Glucagon, in response to falling glucose concentrations, increases the breakdown of glycogen and the release of glucose from the liver. There are many other hormones that play a part in assisting the functions of insulin and glucagon. Failures in the appropriate production of such hormones may lead to the unregulated changes in plasma glucose and subsequent health problems.  相似文献   
72.
正The ascending reticular activating system(ARAS)plays a key role in the control of arousal and awareness for consciousness(Paus,2000;Zeman,2001;Van der Werf et al.,2002;Weiss et al.,2007;Siposan and Aliu,2014).It is well known that the ARAS originates from the reticular formation(RF)of the brainstem,and connects to the cerebral cortex via intralaminar  相似文献   
73.

Background  

An aqueous extract of multi-hypoglycemic herbs of Panax ginseng C.A.Meyer, Pueraria lobata, Dioscorea batatas Decaisne, Rehmannia glutinosa, Amomum cadamomum Linné, Poncirus fructus and Evodia officinalis was investigated for its anti-diabetic effects in cell and animal models.  相似文献   
74.
Even with the increasing importance being placed on research into immigrant elders’ healthcare use as countries change their policies to reflect their increasing immigrant and aging populations, little research has examined changes in healthcare use disparities between immigrant and native elders in relation to these policy changes. To fill this gap in the literature, this study examined healthcare disparities in relation to the welfare reform that the US implemented in 1996 and then compared significant indicators of immigrants’ healthcare use during the pre- and post-reform periods. The difference-in-difference (DD) analyses and post hoc probing of the DD analyses were used in multivariate logistic regression of the National Health Information Survey data that were pooled for the pre- and post-reform periods. The results revealed that while inequalities in healthcare existed before the reform, they significantly increased after the reform. A further test showed that the changes in the inequalities were significant among relatively long-stay immigrants, but not significant among immigrants who entered the US before the reform and thus were exempted from the reform restrictions. During the pre-reform period, insurance, employment, sex, and race/ethnicity were related to healthcare use; however, the enabling factors (i.e., insurance, income, and education) and social structural factors (i.e., marital status, family structure, length of US residency, race/ethnicity, and geographical region) explained the post-reform immigrants’ healthcare use, while controlling for healthcare needs factors. These findings suggest that welfare reform may be the driving force of inequalities in healthcare.  相似文献   
75.
Chronic kidney disease (CKD) is caused by dysfunctional kidneys, which result in complications like cardiovascular diseases. Chronic kidney disease-induced pathophysiological conditions decrease efficacy of autologous mesenchymal stem/stromal cell (MSC)-based therapy by reducing MSC functionality. To enhance therapeutic potential in patients with CKD, we isolated exosomes derived from melatonin-treated healthy MSCs (MT exosomes) and assessed the biological functions of MT exosome–treated MSCs isolated from patients with CKD (CKD-MSCs). Treatment with melatonin increased the expression of cellular prion protein (PrPC) in exosomes isolated from MSCs through the upregulation of miR-4516. Treatment with MT exosomes protected mitochondrial function, cellular senescence, and proliferative potential of CKD-MSCs. MT exosomes significantly increased the level of angiogenesis-associated proteins in CKD-MSCs. In a murine hindlimb ischemia model with CKD, MT exosome–treated CKD-MSCs improved functional recovery and vessel repair. These findings elucidate the regenerative potential of MT exosome–treated CKD-MSCs via the miR-4516-PrPC signaling axis. This study suggests that the treatment of CKD-MSCs with MT exosomes might be a powerful strategy for developing autologous MSC-based therapeutics for patients with CKD. Furthermore, miR-4516 and PrPC could be key molecules for enhancing the regenerative potential of MSCs in ischemic diseases.  相似文献   
76.
77.
78.
79.
Aim: In spite of several reports of an increased risk of sudden infant death syndrome (SIDS) in connection with bed‐sharing, it is not an uncommon practice. The aim of this study was to examine bed‐sharing at 6 months of age and the factors that are associated with bed‐sharing. Methods: Our cohort comprised 8176 randomly chosen families. At 6 month of age, the families received an invitation to the study, with a questionnaire, which was completed by 5605 families (response rate 68.5%). Results: Of the families, 19.8% bed‐shared. In the multivariate analysis, we found a correlation between breast‐feeding and bed‐sharing (breast‐feeding at 6 months: OR 1.94; 95% CI 1.56, 2.41). Moreover, we found an association with 3+ nightly awakenings at 6 months (2.70; 2.20, 3.32). It was more common to share a bed if the parent was single (2.04; 1.19, 3.51) and less common if the infant was bottle‐fed in the first week (0.70; 0.54, 0.90). Never using a pacifier was associated with a higher frequency of bed‐sharing. Conclusion: We found a correlation between breast‐feeding and bed‐sharing as well as between sleeping problems and a single parent. A lower percentage of infants sleeping in the parental bed were seen in association with formula feeding in the first week after birth.  相似文献   
80.
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