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   234篇
  免费   7篇
  国内免费   2篇
儿科学   13篇
妇产科学   4篇
基础医学   14篇
口腔科学   6篇
临床医学   13篇
内科学   80篇
皮肤病学   29篇
神经病学   15篇
特种医学   3篇
外科学   12篇
综合类   2篇
预防医学   10篇
药学   18篇
肿瘤学   24篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2019年   2篇
  2018年   4篇
  2017年   3篇
  2016年   1篇
  2015年   6篇
  2014年   7篇
  2013年   5篇
  2012年   13篇
  2011年   15篇
  2010年   10篇
  2009年   7篇
  2008年   11篇
  2007年   10篇
  2006年   14篇
  2005年   9篇
  2004年   13篇
  2003年   10篇
  2002年   7篇
  2001年   6篇
  2000年   6篇
  1999年   8篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   5篇
  1994年   7篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   3篇
  1989年   4篇
  1988年   9篇
  1987年   9篇
  1986年   7篇
  1985年   6篇
  1984年   4篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
排序方式: 共有243条查询结果,搜索用时 15 毫秒
61.
Two cases of fixed drug eruption, occurring in a mother and son, are presented. The eruption in the mother occurred after she ingested dimenhydrinate or acetylsalicylic acid and in the son after ingestion of either of the above drugs or with "junk" food (cheese crisps). Apart from the drugs, anxiety was found to be an essential factor in the manifestation of the mother's disease. A genetic predisposition would seem to link these cases.  相似文献   
62.
The 60 MHz (1)H NMR spectra of the potent hallucinogen 2,5-dimethoxy-4-ethylamphetamine ("DOEt"), 1, have been studied in CDCl(3) at 28 degrees with the achiral shift reagent, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III), 2, and the chiral reagents tris[3-(trifluoromethylhydroxymethylene)-d-camphorato] europium(III), 3, and tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato] europium(III), 4. Distinct enantiomeric shift differences, DeltaDeltadelta, were observed for the amphetamine CH(3) and the adjacent CH resonances using either 3 or 4 that permit direct optical purity determinations. A novel use of an external computing integrator as an accessory to a basic NMR is described; interfacing these instruments permits improved analytical precision for the reported optical purity determinations using nonracemic mixtures of known compositions. Relative abundances of the different conformers with respect to C(alpha)C(beta) bond rotation in the arylethylamine moiety is discussed based on coupling constants. Results are compared with the related hallucinogen, 3,4-methylenedioxyamphetamine.  相似文献   
63.
64.
In this study, a comprehensive methodology for modelling the hepatitis C virus (HCV) epidemic is proposed to predict the future disease burden and assess whether the recent decline in the incidence of HCV may affect the future occurrence of cirrhosis and hepatocellular carcinoma (HCC) cases. Using the prevalence of HCV, the distribution of chronic hepatitis C (CHC) patients within the various transmission groups and their infection-onset times, it was possible to reconstruct the incident infections per year in the past that progressed to CHC in Greece. The natural history of the disease was simulated in subcohorts of newly infected subjects using transition probabilities derived either empirically between fibrosis stages 0-4 or from literature review. Annual estimates of the incidence and prevalence of CHC by fibrosis stage, HCC and mortality in Greece were obtained up to 2030. HCV incidence peaked in the late 1980s at five new infections/10,000 person-years. Under the assumption of 20-100% decline in HCV incidence after 1990, the cumulative number of incident cirrhosis and HCC cases from 2002-2030 was projected to be lower by 9.6-48.2% and 5.9-29.5%, respectively, than that estimated under the assumption of no decline. However, the prevalent cirrhotic/HCC cases and HCV-related deaths are predicted to decline in the next 30 years only under the assumption of complete elimination of new HCV infections after 1990. Despite the progress in the reduction of HCV transmission, primary prevention does not seem adequate to reverse the rise in the incidence of cirrhosis and HCC.  相似文献   
65.
Digestive Diseases and Sciences - Prolonged biliary stenting may be considered in high-risk patients with irretrievable bile duct stones (IBDS). Distal stent migration (DSM) is a known...  相似文献   
66.
OBJECTIVES: Our study compared the efficacy of bipolar electrocoagulation (gold probe) with 10-Fr (group A) versus 7-Fr (group B) catheter after adrenaline injection in the treatment of bleeding peptic ulcers. METHODS: A total of 77 consecutive patients with endoscopic evidence of peptic ulcer with active bleeding or a nonbleeding visible vessel were randomly assigned to one of the above protocols. Thirty-nine patients (31 male, eight female, mean age 62 yr) were included in group A and 38 (28 male, 10 female, mean age 61 yr) in group B. RESULTS: The initial hemostasis rate, rebleeding rate, duration of hospital stay, volume of blood transfused, number of operations needed, and number of deaths were not significantly different between the two groups. The mean number of electrocoagulations and the subsequent mean duration of electrocoagulations were significantly higher in group B patients (7.0 +/- 3.8 and 14.1 +/- 7.6 s, respectively) compared with those of group A (4.6 +/- 2.6 and 9.3 +/- 5.3 s, respectively) (p < 0.01). Multivariate stepwise logistic regression analysis revealed that among sex, age, location of bleeding, ulcer size, endoscopic severity of bleeding, and the size of the gold probes, lesser endoscopic severity of bleeding (chi(2) = 31.1, p < 0.01), large size of the gold probe (chi(2) = 23.9, p < 0.01), and small ulcer size (chi(2) = 13.4, p < 0.01) were the only factors significantly associated with a smaller number of electrocoagulations. CONCLUSIONS: In this study, the use of large-size gold probes was significantly associated with a lower number of electrocoagulations, resulting in the reduction of electrocoagulation duration. However, the clinical relevance of these findings is questionable because the efficacy of both sizes of gold probe after adrenaline injection in the treatment of bleeding peptic ulcers was similar.  相似文献   
67.
AimsTo evaluate the association of 174G > C polymorphism on interleukin-6 (IL-6) gene with diabetic nephropathy in patients with type 2 diabetes.MethodsA total of 393 Greek subjects with type 2 diabetes (mean age 66.5 ± 10.0 years, men n = 203, women n = 190) were examined. Diabetic nephropathy was defined as presence of microalbuminuria and/or proteinuria. The IL-6 174G > C polymorphism was detected by polymerase chain reaction and appropriate restriction enzyme digestion. High sensitivity C-reactive protein was assayed by particle-enhanced immunonephelometry.ResultsThe genotype distribution (%) was GG: 49.1, GC: 26.8 and CC: 24.1, with no gender difference. The CC homozygotes had lower albumin excretion (mg/24 h) in comparison with the GC genotype [CC: 8.9 (4.0–20.9) vs GC: 21.95 (9.1–53.35), P = 0.004]. Participants with the GC genotype tended to have more frequently nephropathy than those with the GG or the CC genotype [GC: 44.55% vs GG: 35.1% and CC: 28.3%, P = 0.07)]. The CC homozygotes in comparison with GC heterozygotes had lower odds to have nephropathy (odds ratio: 0.51, 95% confidence intervals = 0.28–0.91, P = 0.02), even after adjustment for sex, age, duration of diabetes, body mass index, smoking, hypertension, lipids and glycated hemoglobin, (P = 0.01).ConclusionIn type 2 diabetes states, CC homozygotes have lower albumin excretion and are protected from nephropathy in comparison with GC genotypes.  相似文献   
68.

Background

Fibrinogen is a coagulation/inflammatory biomarker strongly associated with atherogenesis. Data have reported that the genetic variability on fibrinogen chains may affect the atherosclerotic process and the risk of coronary artery disease (CAD). We examined the combined effects of the G455A and the G58A fibrinogen genetic polymorphisms on prothrombotic profile, endothelial function and the risk of CAD in a Caucasian population.

Methods

We recruited 422 patients with angiographically documented CAD and 277 controls matched for age and gender. The two polymorphisms were genotyped by polymerase chain reaction and restriction endonuclease digestion. Fibrinogen and D-Dimers levels, as well as factors' (f) V, X activity were measured by standard coagulometry techniques. Endothelial function was assessed by the flow mediated dilatation (FMD) of the brachial artery.

Results

The two polymorphisms had no significant effect on the risk for CAD. Although the 58AA subjects had not significantly different levels of fibrinogen compared with the 58GG + GA in both groups (p = NS), we importantly found that the 455AA homozygosity was associated with increased fibrinogen levels not only in the control group (p = 0.035), but also in the CAD group (p < 0.001) compared to the G allele carriers. Moreover, both the 58AA (p = 0.016) and 455AA homozygotes (p = 0.022) presented with higher levels of D-Dimers in the CAD group. Interestingly, the 455AA homozygotes had increased fV activity in the CAD group (p = 0.048). However, no significant effects were observed on fX activity and FMD.

Conclusions

Both fibrinogen polymorphisms are capable to modify the atherosclerotic process via their effects on the coagulation cascade.  相似文献   
69.
70.
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