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   803篇
  免费   69篇
  国内免费   27篇
耳鼻咽喉   5篇
儿科学   15篇
妇产科学   3篇
基础医学   24篇
口腔科学   8篇
临床医学   127篇
内科学   108篇
皮肤病学   5篇
神经病学   8篇
特种医学   1篇
外国民族医学   1篇
外科学   70篇
综合类   49篇
预防医学   17篇
药学   397篇
中国医学   46篇
肿瘤学   15篇
  2024年   1篇
  2023年   12篇
  2022年   15篇
  2021年   26篇
  2020年   31篇
  2019年   33篇
  2018年   22篇
  2017年   26篇
  2016年   22篇
  2015年   31篇
  2014年   46篇
  2013年   76篇
  2012年   43篇
  2011年   33篇
  2010年   32篇
  2009年   29篇
  2008年   32篇
  2007年   25篇
  2006年   38篇
  2005年   35篇
  2004年   28篇
  2003年   20篇
  2002年   25篇
  2001年   23篇
  2000年   22篇
  1999年   20篇
  1998年   31篇
  1997年   15篇
  1996年   12篇
  1995年   15篇
  1994年   12篇
  1993年   6篇
  1992年   7篇
  1991年   4篇
  1990年   9篇
  1989年   8篇
  1988年   7篇
  1987年   3篇
  1986年   6篇
  1985年   4篇
  1984年   4篇
  1983年   2篇
  1981年   2篇
  1980年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
排序方式: 共有899条查询结果,搜索用时 15 毫秒
1.
Inappropriate use of acetaminophen (APAP) can lead to morbidity and mortality secondary to hepatic necrosis. Ginsenoside Rg1 is a major active ingredient in processed Panax ginseng, which is proved to elicit biological effects. We hypothesized the beneficial effect of Rg1 on APAP-mediated hepatotoxicity was through Nrf2/ARE pathway. The study was conducted in cells and mice, comparing the actions of Rg1. Rg1 significantly improved cell survival rates and promoted the expression of antioxidant proteins. Meanwhile, Rg1 reduced the excessive ROS and the occurrence of cell apoptosis, which were related to Nrf2/ARE pathway. Expression of Nrf2 has a certain cell specificity.

  相似文献   

2.
3.
新Vierordt法测定鲁南贝特片中两组分的含量   总被引:1,自引:0,他引:1  
目的测定鲁南贝特片中氯唑沙宗和对乙酰氨基酚的含量。方法采用新Vierordt法不经提取分离直接测定两组分的含量 ,测定波长λ1=2 4 3.9nm ,λ2 =2 5 7.6nm。结果氯唑沙宗线性范围为 (8.4 7~ 4 2 .36 ) μg/ml,r=0 .9990 ,对乙酰氨基酚线性范围为 (8.83~ 4 4 .16 ) μg/ml,r =0 .9994 ,氯唑沙宗和对乙酰氨基酚的平均回收率和相对标准偏差分别为 10 0 .1%、0 .89%和 10 0 .6 %、0 .4 4 %。结论该方法简便、快速、重现性好 ,可消除两组分的相互干扰 ,结果满意。  相似文献   
4.
Nodular hyperplasia surrounding fibrolamellar carcinoma   总被引:2,自引:0,他引:2  
We report a case of acetaminophen-induced liver necrosis in a 14-year-old girl. At autopsy, a 9 cm subcapsular nodule was present in the right lobe of the liver which showed distinct zonation: a central greyish white area of fibrolamellar carcinoma with a peripheral fleshy, tan-coloured rim ranging from 1 to 2 cm in thickness. This peripheral zone consisted of nodular, hyperplastic parenchyma resembling the changes seen in focal nodular hyperplasia, and stood out from the adjacent necrotic parenchyma. The sparing of this zone from the deleterious effects of acetaminophen provides indirect evidence of a predominantly arterial rather than portal blood supply to this region. The arterial supply was most probably derived from the tumour vasculature and may explain the parenchymal hyperplasia sometimes reported adjacent to a fibrolamellar carcinoma. Awareness of this phenomenon is essential when evaluating a needle biopsy, as sampling of this region may lead to a false negative diagnosis.  相似文献   
5.
This work deals with the UV spectrophotometric quantitation of a mixture of compounds with overlapped spectra. The mixture spectrum is resolved by use of three computational programs based on different algorithms, namely Multicomponent Analysis (commercial software available from Hewlett-Packard), MULTIC (relying on multiple regression analysis) and SIMPLEX. The results obtained for mixtures of acetylsalicylic acid, acetaminophen and caffeine in commercial analgesic formulations, are compared.  相似文献   
6.
Kaneo  Yoshiharu  Fujihara  Yumie  Tanaka  Tetsuro  Kozawa  Yoko  Mori  Hideki  Iguchi  Sadao 《Pharmaceutical research》1989,6(12):1025-1031
Glutathione was covalently attached to dextran (T-40) by the CNBr activation method. The compound obtained was a water-soluble powder containing 10 (w/w%) glutathione, which was gradually released from the conjugate in aqueous media. Mice depleted of glutathione by treatment with buthionine sulfoximine, a potent inhibitor of -glutamylcysteine synthetase, exhibited a significant increase in hepatic glutathione level after intravenous injection of the conjugate. In mice given a lethal dose of acetaminophen, the survival rate increased progressively with coadministration of the conjugate, whereas little improvement was found when free glutathione was given. The conjugate maintained the serum transaminase activities at lower level after acetaminophen administration. These findings suggest that the dextran conjugate of glutathione is transported into hepatic cells and is intracellulary hydrolyzed to free form, which protects mice from hepatotoxicity due to acetaminophen.  相似文献   
7.
The unit impulse response theory has been adapted to characterize the transport profile of drugs into the central nervous system (CNS). From the obtained input function, the cumulative plasma volume (V) cleared by transport into the CNS in time can be calculated. Simulation studies demonstrated that transport governed by passive diffusion resulted in a linear relationship between V and time, while the slope of the line, the blood- brain barrier (BBB) clearance, proved to be an adequate and model independent parameter to characterize drug transport into the CNS. The error in the result of the numerical procedure could be limited to less than 10% of the theoretically predicted value. Superposition of 5 or 10% random noise on simulated data did not result in significant differences between the calculated and theoretically predicted clearance values. Simulations of carrier-mediated transport resulted in nonlinear transport curves; the degree of nonlinearity, and thus the detectability, was dependent on the initial degree of saturation of the system, the rate of desaturation, as caused by drug elimination processes and the noise level on the data. In vivoexperiments in the rat were performed, using atenolol, acetaminophen, and antipyrine as model drugs. Linear transport relationships were obtained for all drugs, indicating that transport was dependent on passive diffusion or a low affinity carrier system. BBB- clearance values were 7±1 l/min for atenolol, 63±7 ul/min for acetaminiphen and 316±25 l/min for antipyrine. These experiments validate the applicability of the presented technique in in vivostudies.  相似文献   
8.
9.
BACKGROUND: We recently found that paracetamol (acetaminophen) use in late pregnancy was associated with an increased risk of early wheezing in the offspring. OBJECTIVE: To see whether use of paracetamol in late pregnancy is associated with an increased risk of asthma, wheezing and other atopic outcomes in the child at school age. METHODS: In the population-based Avon Longitudinal Study of Parents and Children, we measured associations of paracetamol and aspirin use in late pregnancy (20-32 weeks) with asthma, hayfever, eczema (n = 8511) and wheezing (8381) in the offspring at 69-81 months, and with atopy (positive skin prick test to Dermatophagoides pteronyssinus, cat or grass, n = 6527) and blood total IgE (n = 5148) at 7 years. We used logistic and linear regression to analyse binary outcomes and log-transformed IgE, respectively, controlling for potential confounders. RESULTS: Use of paracetamol, but not aspirin, in late pregnancy was positively associated with asthma (odds ratios (ORs), comparing children whose mothers took paracetamol 'sometimes' and 'most days/daily' with those whose mothers never took it, 1.22 (95% confidence interval (CI): 1.06-1.41) and 1.62 (95% CI: 0.86-3.04), respectively; P trend = 0.0037), wheezing (ORs 1.20 (95% CI: 1.02-1.40) and 1.86 (95% CI: 0.98-3.55), respectively; P trend = 0.011), and total IgE (geometric mean ratios 1.14 (95% CI: 1.03-1.26) and 1.52 (95% CI: 0.98-2.38), respectively; P trend = 0.0034), but not hayfever, eczema or skin test positivity. The proportion of asthma attributable to paracetamol use in late pregnancy, assuming a causal relation, was 7%. CONCLUSION: Paracetamol exposure in late gestation may cause asthma, wheezing and elevated IgE in children of school age.  相似文献   
10.
利用系数倍率双波长标准加入法,同时测定了复方阿司匹林中阿司匹林、扑热息痛和咖啡因的含量。其方法简单、快速,组分可不经分离同时测定。3组分中阿司匹林、扑热息痛和咖啡因的测定线性范围分别为0~40mg/L、0~20mg/L、0~6mg/L。相对标准差是:3.8%、3.8%、7.5%。  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