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   8459篇
  免费   424篇
  国内免费   13篇
耳鼻咽喉   158篇
儿科学   498篇
妇产科学   175篇
基础医学   748篇
口腔科学   120篇
临床医学   471篇
内科学   1652篇
皮肤病学   238篇
神经病学   706篇
特种医学   277篇
外科学   1483篇
综合类   321篇
一般理论   1篇
预防医学   405篇
眼科学   336篇
药学   568篇
中国医学   25篇
肿瘤学   714篇
  2023年   39篇
  2022年   86篇
  2021年   218篇
  2020年   146篇
  2019年   178篇
  2018年   221篇
  2017年   138篇
  2016年   190篇
  2015年   173篇
  2014年   317篇
  2013年   401篇
  2012年   584篇
  2011年   626篇
  2010年   356篇
  2009年   318篇
  2008年   505篇
  2007年   534篇
  2006年   510篇
  2005年   438篇
  2004年   395篇
  2003年   363篇
  2002年   285篇
  2001年   153篇
  2000年   171篇
  1999年   158篇
  1998年   73篇
  1997年   75篇
  1996年   67篇
  1995年   43篇
  1994年   33篇
  1993年   33篇
  1992年   61篇
  1991年   58篇
  1990年   51篇
  1989年   57篇
  1988年   45篇
  1987年   63篇
  1986年   53篇
  1985年   58篇
  1984年   58篇
  1983年   36篇
  1978年   29篇
  1977年   30篇
  1974年   34篇
  1973年   49篇
  1972年   42篇
  1971年   37篇
  1970年   30篇
  1969年   35篇
  1968年   36篇
排序方式: 共有8896条查询结果,搜索用时 234 毫秒
91.
Although the effects of alcohol on brain-derived neurotrophic factor (BDNF) have been extensively studied in rodents, BDNF levels have rarely been measured in abstinent, alcohol-dependent (AD) individuals. Interpretation of reported group comparisons of serum BDNF levels is difficult due to limited information regarding analytical variance, biological variability, and the relative contribution of platelet and plasma pools to serum BDNF. Analytical variance (intra- and inter-assay coefficients of variation) of the enzyme-linked immunosorbent assay (ELISA) was characterized. Within- and between-subject variability, and group differences in serum and plasma BDNF, was assessed on three separate days in 16, 4-week abstinent AD individuals (7M/9F) and 16 social drinkers (SDs; 8M/8F). Significantly higher mean (±sd) serum BDNF levels were observed for the AD group compared to the SD (p = 0.003). No significant difference in mean baseline plasma BDNF levels was observed between AD and SD groups. The low analytical variance, high day-to-day within-individual stability and the high degree of individuality demonstrates the potential clinical utility of measuring serum BDNF levels. The low correlations that we observed between plasma and serum levels are congruent with their representing separate pools of BDNF. The observation of higher basal serum BDNF in the AD group without a concomitant elevation in plasma BDNF levels indicates that the elevated serum BDNF in AD patients is not due to greater BDNF exposure. Further research is warranted to fully elucidate mechanisms underlying this alteration and determine the utility of serum BDNF as a predictor or surrogate marker of chronic alcohol abuse.  相似文献   
92.
93.
94.
Worldwide increases in diabetes prevalence in the face of limited medical resources have prompted international interest in innovative healthcare delivery models. Project ECHO (Extension for Community Healthcare Outcomes) is a “telementoring” program which has been shown to increase capacity for complex disease management in medically underserved regions. In contrast to a traditional telemedicine model which might connect a specialist with one patient, the ECHO model allows for multiple patients to benefit simultaneously by building new expertise. We recently applied the ECHO model to improve health outcomes of patients with complex diabetes (Endo ECHO) living in rural New Mexico. We describe the design of the Endo ECHO intervention and a 4-year, prospective program evaluation assessing health outcomes, utilization patterns, and cost-effectiveness. The Endo ECHO evaluation will demonstrate whether and to what extent this intervention improves outcomes for patients with complex diabetes living in rural New Mexico, and will serve as proof-of-concept for academic medical centers wishing to replicate the model in underserved regions around the world.  相似文献   
95.
Systemic administration of folic acid (FA) in mice was used for studying the pathogenesis associated with acute renal failure (ARF). However, the mechanism by which FA induces ARF remains poorly understood. The present study therefore, was planned to investigate the effect of folic acid administration on prooxidant state and associated ultrastructural changes in renal tissue. Balb/c male mice of 4–6 weeks old were divided into control and two folic acid treatment groups (Groups A and B). The animals in group A were administered intraperitoneal injection of folic acid (100 mg kg?1 body weight) for a period of 7 consecutive days while the animal in group B were administered a single intraperitoneal dose of folic acid (250 mg kg?1 body weight). The renal tissues were collected and used for the analyses of lipid peroxidative indices and activities of antioxidant enzymes in renal tissues. To corroborate biochemical findings scanning electron microscopy (SEM) in renal tissue was studied. Folic acid treated animals demonstrated marked renal hypertrophy accompanied by severe impairment of renal function. Glutathione levels (GSH) and antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) levels were significantly decreased and LPO levels increased following FA treatment. SEM results further substantiated the observed biochemical changes as evident by severe inflammation in glomeruli, swelling in primary and secondary pedicels, blebbing in villi, and tremendous deprivation of erythrocytes (RBCs) in FA treated kidneys. The present study therefore suggests that acute administration of folic acid leads to the generation of oxidative stress and altered membrane architecture responsible for folic acid induced ARF.  相似文献   
96.
97.
98.
People identified as Very Important Persons (VIPs) often present or are referred to the Emergency Department (ED). Celebrities are a small subset of this group, but many others are included. Triage of these patients, including occasional prioritization, creates practical and ethical challenges. Treatment also provides challenges with the risks of over testing, overtreatment, over consultation, and over or under admission to the hospital. This article presents a practical and ethical framework for addressing the care of VIPs in the ED.  相似文献   
99.
Gallstone disease is common and complications frequently encountered include acute cholecystitis, acute pancreatitis, and cholangitis, but gallbladder perforation (GBP) is rare. A definitive diagnosis is uncommon before surgery and morbidity and mortality associated with this condition are high. Reported incidence ranges between 2 and 10.6 % in patients with acute cholecystitis but is higher in patients managed conservatively. We report here five patients with GBP to show the difficulty in making an early diagnosis.  相似文献   
100.
Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We attempt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO) and American Academy of Ophthalmology (AAO) meetings. In total, 261 relevant publications and 389 conference abstracts were identified.  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