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   3337篇
  免费   175篇
  国内免费   10篇
耳鼻咽喉   40篇
儿科学   148篇
妇产科学   52篇
基础医学   443篇
口腔科学   38篇
临床医学   200篇
内科学   500篇
皮肤病学   46篇
神经病学   237篇
特种医学   94篇
外科学   420篇
综合类   88篇
预防医学   202篇
眼科学   146篇
药学   455篇
中国医学   44篇
肿瘤学   369篇
  2023年   21篇
  2022年   38篇
  2021年   95篇
  2020年   54篇
  2019年   65篇
  2018年   87篇
  2017年   58篇
  2016年   94篇
  2015年   85篇
  2014年   100篇
  2013年   146篇
  2012年   235篇
  2011年   250篇
  2010年   148篇
  2009年   127篇
  2008年   180篇
  2007年   177篇
  2006年   160篇
  2005年   158篇
  2004年   142篇
  2003年   111篇
  2002年   89篇
  2001年   51篇
  2000年   67篇
  1999年   54篇
  1998年   32篇
  1997年   21篇
  1996年   24篇
  1995年   21篇
  1994年   20篇
  1993年   19篇
  1992年   46篇
  1991年   41篇
  1990年   33篇
  1989年   55篇
  1988年   44篇
  1987年   40篇
  1986年   34篇
  1985年   32篇
  1984年   28篇
  1983年   27篇
  1982年   15篇
  1981年   16篇
  1979年   34篇
  1978年   15篇
  1976年   14篇
  1974年   10篇
  1973年   16篇
  1972年   15篇
  1970年   10篇
排序方式: 共有3522条查询结果,搜索用时 328 毫秒
81.
Objective:To evaluate the antidiabetic and antioxidant potential of Emblica officinalis(E.officinalis)fruit on normal and type 2 diabetic rats.Methods:Type 2 diabetes was induced into the male Long-Evans rats.The rats were divided into nine groups including control groups receiving water,type 2 diabetic controls,type 2 diabetic rats treated with glibenclamide(T2GT)and type 2diabetic rats treated with aqueous extract of fruit pulp of E.officinalis.They were fed orally for8 weeks with a single feeding.Blood was collected by cutting the tail tip on 0 and 28 days and by decapitation on 56 day.Packed red blood cells and serum were used for evaluating different biochemical parameters.Results:Four weeks administration of aqueous extract of E.officinalis improved oral glucose tolerance in type 2 rats and after 8 weeks it caused significant(P0.007)reduction in fasting serum glucose level compared to 0 day.Triglycerides decreased by 14%but there was no significant change in serum ALT,creatinine,cholesterol and insulin level in any group.Furthermore,reduced erythrocyte malondialdehyde level showed no significant change(P0.07)but reduced glutathione content was found to be increased significantly(P0.05).Conclusions:The aqueous extract of E.officinalis has a promising antidiabetic and antioxidant properties and may be considered for further clinical studies in drug development.  相似文献   
82.
83.
84.

Purpose

Ethanol binge augments liver injury after chronic ethanol consumption in humans, but the mechanism behind the enhanced liver injury by ethanol binge is not known. In this study we used a clinically relevant rat model in which liver injury is amplified by binge after chronic ethanol treatment and investigated the importance of histone modifications.

Methods

Eight-week-old Sprague-Dawley rats were fed ethanol in a liquid diet for 4 weeks. Control rats were fed an isocaloric liquid diet. This was followed by three binge administrations of ethanol (intragastric 5 g/kg body weight, 12 h apart). In the control, ethanol was replaced by water. Four hours after the last binge administration, liver samples were analyzed for histone modifications and parameters of liver injury.

Results

Chronic ethanol administration alone caused an increase in histone H3 ser10 and ser28 (H3S10 or S28) phosphorylation, and binge ethanol reduced their levels. Levels of dually modified phosphoacetylated histone H3 (H3AcK9/PS10) increased after acute binge ethanol and remained same after chronic ethanol binge. In contrast, histone H3 lysine-9 acetylation (H3AcK9) was not increased after chronic ethanol but increased significantly after acute binge and chronic ethanol binge. Increase in histone acetylation was accompanied by increased phospho-ERK1/2 in the nuclear extracts. Increased acetylation after chronic ethanol binge was also accompanied by increased protein levels of GCN5 histone acetyl transferase and a modest increase in HDAC3 in the nucleus. Histone lysine-9 dimethylation was significantly increased after chronic ethanol binge. Chronic ethanol binge also resulted in a decrease in the SAM:SAH ratio with a relative decrease of SAM levels and a corresponding increase in SAH levels.

Conclusions

Ethanol binge after chronic ethanol altered the profile of site-specific histone modifications and may underlie the mechanism of augmented liver injury by chronic-ethanol-binge-treated rats.
  相似文献   
85.
86.
87.
Barrett??s esophagus (BE) is a well-known premalignant condition that can be associated with the development of dysplasia and adenocarcinoma. In the past, esophagectomy was the standard treatment for patients with BE with high grade dysplasia (HGD) and early cancer (EC). However, esophagectomy is not necessarily the only treatment response to HGD and EC anymore. Over the past decade, a number of endoscopic therapies have been developed for management of BE. These include endoscopic mucosal resection, thermal ablation techniques that use laser irradiation, multipolar electrocoagulation, argon plasma coagulation, photodynamic therapy, and the recently developed cryotherapy and radiofrequency ablation.  相似文献   
88.

Background and Aims

Longer life expectancy in patients with prior breast cancer may increase their risk of developing other primary cancers, including colorectal cancer (CRC). Whether the risk of developing CRC in this patient population is higher in comparison to those with no prior cancer remains unclear. The purpose of this study was to compare the prevalence of colorectal adenomas and any CRC in breast cancer survivors with those who have no history of prior cancer and assess any difference with use of antiestrogen therapy.

Methods

We compared the prevalence of colorectal cancer and adenomas in breast cancer survivors with that of a group of matched controls. Eligible survivors were ??85?years of age; had initially been diagnosed with stage 0, I, II, or III breast cancer; had completed all cancer treatments with the exception of adjuvant antiestrogen therapy; and had no evidence of recurrence on follow-up. We used the screening colonoscopy database at our institution to identify age-, sex-, and race-matched controls with no history of cancer.

Results

We identified 302 study-eligible breast cancer survivors and 302 matched controls. No colorectal cancers were found in either group. Forty-one breast cancer survivors and 30 controls had tubular adenomas; four survivors and three controls had villous adenoma; and eight survivors and ten controls had advanced adenoma. Multivariate regression analysis revealed that adjuvant antiestrogen therapy was not significantly associated with an increased risk of advanced adenoma.

Conclusions

The prevalence of colorectal adenomas in breast cancer survivors and controls was similar. Breast cancer survivors, including those receiving adjuvant antiestrogen therapies may follow the colorectal screening guidelines used for average-risk population.  相似文献   
89.
90.
The British Committee for Standards in Haematology first produced guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant in 2000. This revision updates those guidelines and covers the areas of diagnosis, treatment and assessment of response to therapy.  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