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   3127574篇
  免费   278547篇
  国内免费   39994篇
耳鼻咽喉   41012篇
儿科学   88655篇
妇产科学   74038篇
基础医学   498472篇
口腔科学   80210篇
临床医学   295521篇
内科学   525668篇
皮肤病学   83217篇
神经病学   258658篇
特种医学   121124篇
外国民族医学   331篇
外科学   471603篇
综合类   156128篇
现状与发展   108篇
一般理论   2079篇
预防医学   252560篇
眼科学   73591篇
药学   230359篇
  453篇
中国医学   33402篇
肿瘤学   158926篇
  2022年   36282篇
  2021年   71131篇
  2020年   48201篇
  2019年   67969篇
  2018年   79899篇
  2017年   63295篇
  2016年   67582篇
  2015年   88032篇
  2014年   125811篇
  2013年   188659篇
  2012年   100056篇
  2011年   99496篇
  2010年   130270篇
  2009年   132644篇
  2008年   76854篇
  2007年   76410篇
  2006年   87238篇
  2005年   81920篇
  2004年   77443篇
  2003年   68271篇
  2002年   56572篇
  2001年   85003篇
  2000年   76768篇
  1999年   81860篇
  1998年   66351篇
  1997年   64598篇
  1996年   61093篇
  1995年   56448篇
  1994年   50103篇
  1993年   46337篇
  1992年   51100篇
  1991年   47471篇
  1990年   44049篇
  1989年   44281篇
  1988年   40805篇
  1987年   39565篇
  1986年   37198篇
  1985年   37730篇
  1984年   37164篇
  1983年   34847篇
  1982年   37635篇
  1981年   35774篇
  1980年   33735篇
  1979年   28120篇
  1978年   27422篇
  1977年   26176篇
  1976年   23258篇
  1975年   21249篇
  1974年   20192篇
  1973年   19227篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
To determine the protective effect of aloe-emodin (AE) from high glucose induced toxicity in RIN-5F (pancreatic β-cell) cell and restoration of its function was analyzed. RIN-5F cells have been cultured in high glucose (25 mM glucose) condition, with and without AE treatment. RIN-5F cells cultured in high glucose decreased cell viability and increased ROS levels after 48 hr compared with standard medium (5.5 mM glucose). Glucotoxicity was confirmed by significantly increased ROS production, increased pro-inflammatory (IFN-γ, IL-1β,) & decreased anti-inflammatory (IL-6&IL-10) cytokine levels, increased DNA fragmentation. In addition, we found increased Bax, caspase 3, Fadd, and Fas and significantly reduced Bcl-2 expression after 48 hr. RIN-5F treated with both high glucose and AE (20 μM) decreased ROS generation and prevent RIN-5F cell from glucotoxicity. In addition, AE treated cells cultured in high glucose were transferred to standard medium, normal responsiveness to glucose was restored within 8hr and normal basal insulin release within 24 hr was achieved when compared to high glucose.  相似文献   
995.
Treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted by drug delivery to the back of the eye. In recent years, concerted efforts in drug delivery have been made to prolong the residence time of drugs injected in the vitreous humor of the eye. Our previous studies demonstrated that poly(ortho ester) (POE) nanoparticles were biodegradable/biocompatible and were capable of long-term sustained release. The objective of the present study was to investigate the safety and localization of POE nanoparticles in New Zealand white rabbits and C57BL/6 mice after intravitreal administration for the treatment of chronic posterior ocular diseases. Two concentration levels of POE nanoparticles solution were chosen for intravitreal injection: 1.5?mg/ml and 10?mg/ml. Our results demonstrate that POE nanoparticles were distributed throughout the vitreous cavity by optical coherence tomography (OCT) examination 14 days post-intravitreal injection. Intraocular pressure was not changed from baseline. Inflammatory or adverse effects were undetectable by slit lamp biomicroscopy. Furthermore, we demonstrate that POE nanoparticles have negligible toxicity assessed at the cellular level evidenced by a lack of glia activation or apoptosis estimation after intravitreal injection. Collectively, POE nanoparticles are a novel and nontoxic as an ocular drug delivery system for the treatment of posterior ocular diseases.  相似文献   
996.
Multidisciplinary predialysis education and team care (MDC) may slow the decline in renal function in patients with chronic kidney disease (CKD). However, associations between unexpected return during MDC and progression of renal dysfunction have not been characterized in patients with CKD. Our study aimed to determine the association between exacerbation of renal dysfunction and the frequency of unexpected return during follow-up.A total of 437 patients with CKD receiving multidisciplinary care between January 2009 and June 2013 at the Shin-Kong Wu Ho-Su Memorial Hospital were included in this retrospective observational cohort study, and multiple imputations were performed for missing data. The predictor was the frequency of unexpected return for follow-up during the first year after entering MDC. Main outcome was monthly declines in estimated glomerular filtration rates (eGFR). Moreover, the demographic data, comorbidities, history of medication, and routine laboratory data for patients with CKD were collected.Among all patients, 59.7% were male, the mean age at initiation of MDC was 69.4 ± 13.2 years, and the duration of follow-up was 21.4 ± 3.3 months. The subjects were divided into 2 groups according to frequencies of follow-up (≤4 and > 4 visits) during the 1st year of MDC. The patients with CKD were regularly followed up every 3 months as a part of MDC in our hospital, and patients who returned for more than 4 follow-up visits were included in the unexpected return group. In crude regression analyses, unexpected return was significantly associated with higher monthly declines of eGFR (β = 0.092, 95% confidence interval, 0.014–0.170). This association remained after adjustments for multiple variables, and subgroup analyses of unexpected return showed that male gender, older age, CKD stage 1 to 3, hypertension, history of coronary artery disease, and use of renin–angiotensin system blockade were significantly associated with declines in renal function.In conclusion, unexpected return for follow-up during the 1st year of MDC was significantly associated with the deterioration of renal function.  相似文献   
997.
998.
999.
1000.
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