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   6940篇
  免费   430篇
  国内免费   32篇
耳鼻咽喉   45篇
儿科学   160篇
妇产科学   140篇
基础医学   1235篇
口腔科学   198篇
临床医学   592篇
内科学   1274篇
皮肤病学   232篇
神经病学   905篇
特种医学   302篇
外科学   834篇
综合类   40篇
一般理论   4篇
预防医学   338篇
眼科学   106篇
药学   528篇
中国医学   20篇
肿瘤学   449篇
  2023年   63篇
  2022年   76篇
  2021年   160篇
  2020年   126篇
  2019年   167篇
  2018年   163篇
  2017年   121篇
  2016年   164篇
  2015年   206篇
  2014年   277篇
  2013年   300篇
  2012年   519篇
  2011年   587篇
  2010年   340篇
  2009年   341篇
  2008年   545篇
  2007年   486篇
  2006年   457篇
  2005年   429篇
  2004年   433篇
  2003年   404篇
  2002年   358篇
  2001年   58篇
  2000年   53篇
  1999年   65篇
  1998年   68篇
  1997年   58篇
  1996年   45篇
  1995年   36篇
  1994年   45篇
  1993年   31篇
  1992年   25篇
  1991年   24篇
  1990年   17篇
  1989年   11篇
  1988年   16篇
  1987年   13篇
  1986年   18篇
  1985年   10篇
  1984年   6篇
  1983年   17篇
  1982年   4篇
  1981年   6篇
  1979年   5篇
  1978年   5篇
  1977年   4篇
  1976年   4篇
  1971年   4篇
  1969年   3篇
  1968年   3篇
排序方式: 共有7402条查询结果,搜索用时 15 毫秒
1.
2.
3.
We have shown previously that the plant cannabinoid cannabidiol (CBD) elevates intracellular calcium levels in both cultured hippocampal neurones and glia. Here, we investigated whether the main psychotropic constituent of cannabis, Δ9-tetrahydrocannabinol (THC) alone or in combination with other cannabis constituents can cause similar responses, and whether THC affects the responses induced by CBD. Our experiments were performed with 1 μM pure THC (pTHC), with 1 μM pure CBD (pCBD), with a high-THC, low CBD cannabis extract (eTHC), with a high-CBD, low THC cannabis extract (eCBD), with a mixture of eTHC and eCBD (THC:CBD = 1:1) or with corresponding ‘mock extracts’ that contained only pTHC and pCBD mixed in the same proportion as in eTHC, eCBD or the 1:1 mixture of eTHC and eCBD.  相似文献   
4.
5.
6.
It has been demonstrated that total parenteral nutrition (TPN) modulates the function of the hepatic reticuloendothelial system (RES). The objective of this study was to evaluate the impact of two different TPN lipid emulsions on the recovery of allograft RES function after orthotopic liver transplantation (OLTx). In a prospective, double-blind study, OLTx patients were randomly assigned to two treatment groups. Group I ( n=13) received a TPN regimen that included long-chain triglycerides (LCT). Group II ( n=9) received a TPN regimen that included a fat emulsion consisting of both medium-chain triglycerides (MCT) and LCT. At baseline, i.e., on days 2 or 3 after OLTx ( t1), before lipids for TPN were started, hepatic RES function was determined using the human serum albumin millimicrosphere technique (K-value, 1/min). A second measurement ( t2) was obtained after 7 days of TPN, including one of the study's two fat emulsions. The mean (+/- SD) K-value (1/min) was 0.48+/-0.16 in the LCT group and 0.55+/-0.28 in the MCT/LCT group at t1, and it improved to 0.62+/-0.21 in the LCT group and to 0.86+/-0.32 in the MCT/LCT group at t2. RES function recovery was significantly better in the MCT/LCT group ( P< or = 0.05). MCT/LCT emulsion appears to be the TPN fat emulsion of choice after OLTx as it seems to have less impact on hepatic RES recovery.  相似文献   
7.
8.
9.
BACKGROUND: Normal endothelial function depends on nitric oxide (NO) release by endothelial cells. Asymmetric dimethylarginine (ADMA), by competing with L-arginine, inhibits NO production and may lead to endothelial dysfunction and atherosclerotic development. Our aim was to ascertain the association between ADMA and coronary artery calcification (CAC), a marker of atherosclerotic coronary disease burden. DESIGN: A nested case-control study within the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, an observational study among young adults residing in four US cities. METHODS: Participants were 263 white and black male and female cases with the presence of CAC and 263 sex and race-matched controls without evidence of CAC by computed tomography, 33-47 years old in 2000-2001. RESULTS: The median level (range) of ADMA was significantly higher in cases (0.55; 0.20-2.22 micromol/l) than in controls (0.53; 0.32-1.30 micromol/l; P=0.03). In conditional logistic regression adjusting for age, field center, educational attainment, smoking status, alcohol consumption, body mass index, waist circumference, hypertension, diabetes, low-density lipoprotein and high-density lipoprotein-cholesterol, triglycerides, renal function and C-reactive protein, the highest tertile of ADMA, compared with the lowest tertile, was associated with 1.80 (95% confidence interval 1.03-3.15) increased odds of the presence of any CAC. By linear regression, a significant independent relationship was also found between ADMA and the degree of CAC. CONCLUSION: These results support a role for ADMA as a biochemical marker of CAC.  相似文献   
10.
Rufinamide, a triazole derivative that is structurally distinct from currently marketed antiepileptic drugs (AEDs), is in development for the adjunctive treatment of Lennox-Gastaut syndrome (LGS) in children and adults. Rufinamide is well absorbed after oral administration, demonstrates low protein binding, and is metabolized by enzymatic hydrolysis without involvement of cytochrome P450 enzymes, conferring a low drug interaction potential. In a randomized, double-blind trial involving 138 adult and pediatric patients with LGS, compared with placebo, rufinamide 45 mg/kg/day resulted in significantly superior reductions in drop attacks (median change −42.5% vs +1.4% with placebo) and total seizures (−32.1% vs −11.7% with placebo), accompanied by significantly higher responder rates. These results are comparable with findings reported for other AEDs in randomized, controlled clinical trials in patients with LGS. Rufinamide produced statistically significant seizure reduction which was maintained during long-term therapy and accompanied by good tolerability. The most frequently reported adverse events from a pooled safety database evaluating short- and long-term therapy were headache (22.9% and 29.5%), dizziness (15.5% and 22.5%) and fatigue (13.6% and 17.7%). Rufinamide therefore presents a favorable efficacy and tolerability profile and is a promising candidate for the adjunctive therapy of LGS.  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