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   1323篇
  免费   84篇
  国内免费   7篇
耳鼻咽喉   6篇
儿科学   38篇
妇产科学   44篇
基础医学   202篇
口腔科学   25篇
临床医学   105篇
内科学   307篇
皮肤病学   59篇
神经病学   100篇
特种医学   16篇
外科学   133篇
综合类   5篇
一般理论   7篇
预防医学   135篇
眼科学   20篇
药学   100篇
肿瘤学   112篇
  2024年   2篇
  2023年   6篇
  2022年   23篇
  2021年   47篇
  2020年   36篇
  2019年   35篇
  2018年   42篇
  2017年   28篇
  2016年   41篇
  2015年   36篇
  2014年   61篇
  2013年   83篇
  2012年   109篇
  2011年   97篇
  2010年   58篇
  2009年   53篇
  2008年   94篇
  2007年   80篇
  2006年   69篇
  2005年   82篇
  2004年   70篇
  2003年   73篇
  2002年   72篇
  2001年   8篇
  2000年   4篇
  1999年   5篇
  1998年   8篇
  1997年   14篇
  1996年   7篇
  1995年   14篇
  1994年   3篇
  1993年   10篇
  1992年   4篇
  1991年   3篇
  1989年   3篇
  1987年   5篇
  1986年   2篇
  1981年   2篇
  1980年   2篇
  1979年   3篇
  1978年   2篇
  1975年   2篇
  1973年   2篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1954年   1篇
  1928年   1篇
  1927年   3篇
  1920年   1篇
排序方式: 共有1414条查询结果,搜索用时 15 毫秒
11.
The effect of high-dose uridine on body temperatures of rabbits and man has been studied in relation to plasma concentrations of uridine and its catabolite uracil. Uridine induced fever in both rabbits and man. High-dose cytidine had no influence on body temperature in rabbits. Plasma concentrations of uridine were between 1 and 1.5 mM at 30 min after an iv bolus injection of 400 mg uridine/kg in rabbits and reached peak levels of 2 mM after a 1-hr infusion of 12 g uridine/m2 in man. The plasma concentration of cytidine in rabbits was about 0.5 mM and that of uridine was 0.30 mM at 30 min after an iv bolus injection of 400 mg cytidine/kg. The mean residence time for uridine in patients and rabbits varied between 80 and 195 min. The area under the plasma concentration–time curve (AUC) for uridine in rabbits was 2.0 mmol · hr/liter, and that for cytidine was 0.6 mmol · hr/liter. A large AUC for uridine indicates a prolonged exposure of tissues to uridine, which might lead to extensive formation of degradation products. The administration of some of these catabolites, dihydrouracil (at 20–40 mg/kg), carbamyl--alanine (at 60 mg/kg), and -alanine (at 300–400 mg/kg), resulted in a significant increase in body temperature. It is concluded that the change in body temperature associated with uridine administration was not due to bacterial pyrogens but that one of the degradation products might be involved in thermoregulation.  相似文献   
12.
Background: The prompt identification of patients with poor prognosis is essential in order to improve the treatment outcomes in prostate cancer (CaP); as a novel approach, several molecular markers, including integrins, have been discussed as prognostic biomarkers. Our aim was to comprehensively examine aberrant expression of integrins in correlation with clinicopathological features and prognosis in CaP by synthesizing all available evidence, in a systematic review and meta-analysis. Methods: A systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Scientific literature databases (Pubmed, Embase, and Scopus) were systematically searched until May 10, 2020. Random-effects (DerSimonian-Laird) models were used to estimate pooled odds ratios (ORs) for cross-sectional correlations with clinicopathological characteristics and relative risks for longitudinal associations with prognosis. Results: Fourteen studies were included with a total number of 3,194 CaP cases examined (13 cross-sectional and four longitudinal cohort study arms). Correlation of low expression of α6 (pooled OR = 0.10, 95% confidence interval [CI]: 0.04–0.28, P < 0.001) and β1 (pooled OR = 0.45; 95% CI: 0.21–1.00, P = 0.049) integrin with high Gleason score was noted. A borderline trend between reduced expression of α6 integrin and an advanced clinical stage of CaP (pooled OR = 0.48; 95% CI: 0.22-1.03, P = 0.06) was observed. No associations with biochemical recurrence and survival were documented. Conclusions: Evidence on the association of low expression of integrins α6 and β1 and more advanced CaP exist, whereas significant results on survival were not documented; further studies are warranted.  相似文献   
13.
14.
Ex situ normothermic machine perfusion (NMP) is being used increasingly in the assessment of higher risk deceased donor organs and to facilitate prolonged organ storage. Third-party packed red blood cells (pRBCs) are often used as an oxygen carrier in the perfusate of ex situ NMP. Despite the increasing interest in NMP, comparatively little attention has been paid to the appropriate selection of pRBCs. This includes the choice of ABO blood group and Rhesus D status, the need for special requirements for selected recipients, and the necessity for traceability of blood components. Flushing organs with cold preservation solution after NMP removes the overwhelming majority of third-party allogeneic pRBCs, but residual pRBCs within the organ may have biologically relevant effects following implantation as they enter the recipient's circulation. This review considers these issues, and suggests that national transplant and blood transfusion agencies work together to develop a co-ordinated approach within each country. This is especially important given the possibility of organ re-allocation between centers after ex situ NMP, and the ongoing development of organ perfusion hubs.  相似文献   
15.
16.
Objective: Whole grain consumption has long been associated with human health. However, its relationship with breast cancer remains not well understood and appreciated. The aim of this work was to evaluate the association between whole grain consumption and breast cancer in women. Methods: A case-control study was designed. Two hundred and fifty consecutive, newly diagnosed breast cancer female patients (56 ± 12 years) and 250 one-to-one age-matched controls were enrolled. A standardized, validated questionnaire assessing various sociodemographic, clinical, lifestyle, and dietary characteristics was applied through face-to-face interviews. Moreover, data on regular consumption of whole grains (i.e., never/rarely, 1–6 times/week, >7 times/week) were recorded. Overall dietary habits were assessed through the level of adherence to the Mediterranean diet using the MedDietScore (theoretical range 0–55). Results: Whole grain consumption of more than 7 times/week was associated with a 0.49-fold (odds ratio = 0.49; 95% confidence interval, 0.29, 0.82) lower likelihood of having breast cancer, after adjustments were made. Conclusions: This study suggested that whole grain consumption more than 7 times/week was consistently associated with reduced risk of breast cancer.  相似文献   
17.
18.
19.
20.
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