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   224篇
  免费   15篇
  国内免费   10篇
耳鼻咽喉   1篇
儿科学   9篇
妇产科学   20篇
基础医学   30篇
临床医学   28篇
内科学   51篇
皮肤病学   2篇
神经病学   16篇
特种医学   3篇
外科学   22篇
综合类   9篇
预防医学   16篇
眼科学   12篇
药学   26篇
肿瘤学   4篇
  2021年   4篇
  2020年   2篇
  2019年   1篇
  2017年   3篇
  2016年   1篇
  2015年   4篇
  2014年   6篇
  2013年   14篇
  2012年   9篇
  2011年   5篇
  2010年   7篇
  2009年   5篇
  2008年   10篇
  2007年   10篇
  2006年   12篇
  2005年   10篇
  2004年   8篇
  2003年   9篇
  2002年   15篇
  2001年   12篇
  2000年   6篇
  1999年   4篇
  1998年   2篇
  1997年   4篇
  1996年   7篇
  1995年   5篇
  1994年   4篇
  1993年   2篇
  1992年   5篇
  1991年   3篇
  1990年   3篇
  1989年   7篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   6篇
  1984年   7篇
  1983年   2篇
  1982年   2篇
  1979年   1篇
  1978年   2篇
  1975年   1篇
  1974年   4篇
  1972年   4篇
  1969年   2篇
  1967年   2篇
  1966年   1篇
  1965年   1篇
  1954年   1篇
  1936年   1篇
排序方式: 共有249条查询结果,搜索用时 15 毫秒
241.
目的探讨抗Sm抗体、抗双链DNA抗体、抗核抗体联合检测对SLE的诊断意义。方法用免疫印迹法(IBT)、胶体金斑点免疫渗滤法(DIGFA)、间接免疫荧光技术(IIF)检测抗Sm抗体、抗双链DNA抗体、抗核抗体。结果67例SLE患者中,抗Sm抗体、抗双链DNA抗体、抗核抗体阳性率分别为29.9%、65.7%、82.1%,三者综合阳性率97.0%,明显高于单项检测阳性率,经统计学处理,有显著性意义(P<0.01)。其中9例抗Sm抗体、抗双链DNA抗体均为阴性,而抗核抗体为阳性;1例抗双链DNA抗体为阳性,而抗Sm抗体、抗核抗体均为阴性。结论联合检测可避免因单项检测出现的漏诊情况,起到相互补充、相互印证,从而提高SLE确诊率的作用。  相似文献   
242.
Deletions of chromosome 22q11 are common in patients with tetralogy of Fallot, and in those with absent pulmonary valve syndrome. In this report, we describe a pair of siblings with absent pulmonary valve syndrome, neither of whom had deletions of chromosome 22q11. The finding of familial absent pulmonary valve syndrome without deletion of 22q11 in our patients suggests an alternative genetic basis for this rare condition.  相似文献   
243.
The clinical features, diagnostic studies and surgical treatment of a subvalvular mitral aneurysm of the left ventricle are described. The infant presented at 9 weeks of age with large apical ventricular septal defects and pulmonary hypertension. The subvalvular aneurysm was an incidental finding. Both lesions were treated surgically.  相似文献   
244.
BACKGROUND AND AIM OF THE STUDY: Genetic variants of the angiotensin-converting enzyme (ACE) cascade may influence left ventricular myocardial mass (LVMM) regression after aortic valve surgery. Postoperative long-term changes in LV indices were investigated in patients with asymptomatic aortic regurgitation (AR) and symptomatic aortic stenosis (AS) and related to alleles of ACE polymorphisms. METHODS: A total of 96 patients was included in the study, 21 with class IIa AR (22%) and 75 with class I AS (78%) recommendations for surgery. Patients were evaluated for demographic risk factors and underwent a thorough clinical examination including 3-D cardiac imaging by ultrafast-computed tomography. Genomic DNA was isolated for genotyping. RESULTS: AR patients were younger (55.8 +/- 8.9 versus 64 +/- 9.1 years, p = 0.0014), had a larger body surface area (1.92 +/- 0.21 versus 1.82 +/- 0.19 m2, p = 0.039), and were more likely to be asymptomatic (myocardial infarction, p = 0.04; syncope, p = 0.0099; thromboembolism, p = 0.03; NYHA class IV, p = 0.04). Postoperatively, the reduction in absolute LVMM (from 297.1 +/- 52.6 to 190.1 +/- 57.1 g versus 214.4 +/- 55.7 to 143.8 +/- 40.0 g; pT = 0.0000001) and indexed LVMM (from 156.0 +/- 31.7 to 99.3 +/- 28.4 g/m2 versus 118.7 +/- 28.3 to 79.3 +/- 20.6 g/m; pT = 0.0000001) over time was more significant in AR patients, but never reached normal values. Enforced ACE inhibitor medication resulted in significantly higher postoperative indexed LVMM differences in homozygote DD patients compared to AR patients with II/ID alleles of ACE 16 ins/del polymorphism. CONCLUSION: AR patients showed a statistically significant decrease in absolute/indexed LVMM during follow up, but never achieved LV mass recovery compared to standard values or to values in patients undergoing aortic valve replacement for AS. The benefits of ACE inhibitors were observed among AR patients with homozygote DD alleles of ACE 16 ins/del polymorphism.  相似文献   
245.
About half of all deaths are due to cardiovascular disease and its complications. The economic burden on society and the healthcare system from cardiovascular disability, complications, and treatments is huge and getting larger in the rapidly aging populations of developed countries. As conventional risk factors fail to account for part of the cases, homocysteine, a "new" risk factor, is being viewed with mounting interest. Homocysteine is a sulfur-containing intermediate product in the normal metabolism of methionine, an essential amino acid. Folic acid, vitamin B12, and vitamin B6 deficiencies and reduced enzyme activities inhibit the breakdown of homocysteine, thus increasing the intracellular homocysteine concentration. Numerous retrospective and prospective studies have consistently found an independent relationship between mild hyperhomocysteinemia and cardiovascular disease or all-cause mortality. Starting at a plasma homocysteine concentration of approximately 10 micromol/l, the risk increase follows a linear dose-response relationship with no specific threshold level. Hyperhomocysteinemia as an independent risk factor for cardiovascular disease is thought to be responsible for about 10% of total risk. Elevated plasma homocysteine levels (>12 micromol/l; moderate hyperhomocysteinemia) are considered cytotoxic and are found in 5 to 10% of the general population and in up to 40% of patients with vascular disease. Additional risk factors (smoking, arterial hypertension, diabetes, and hyperlipidemia) may additively or, by interacting with homocysteine, synergistically (and hence over-proportionally) increase overall risk. Hyperhomocysteinemia is associated with alterations in vascular morphology, loss of endothelial anti-thrombotic function, and induction of a procoagulant environment. Most known forms of damage or injury are due to homocysteine-mediated oxidative stress. Especially when acting as direct or indirect antagonists of cofactors and enzyme activities, numerous agents, drugs, diseases, and lifestyle factors have an impact on homocysteine metabolism. Folic acid deficiency is considered the most common cause of hyperhomocysteinemia. An adequate intake of at least 400 microg of folate per day is difficult to maintain even with a balanced diet, and high-risk groups often find it impossible to meet these folate requirements. Based on the available evidence, there is an increasing call for the diagnosis and treatment of elevated homocysteine levels in high-risk individuals in general and patients with manifest vascular disease in particular. Subjects of both populations should first have a baseline homocysteine assay. Except where manifestations are already present, intervention, if any, should be guided by the severity of hyperhomocysteinemia. Consistent with other working parties and consensus groups, we recommend a target plasma homocysteine level of <10 micromol/l. Based on various calculation models, reduction of elevated plasma homocysteine concentrations may theoretically prevent up to 25% of cardiovascular events. Supplementation is inexpensive, potentially effective, and devoid of adverse effects and, therefore, has an exceptionally favorable benefit/risk ratio. The results of ongoing randomized controlled intervention trials must be available before screening for, and treatment of, hyperhomocysteinemia can be recommended for the apparently healthy general population.  相似文献   
246.
247.

Background

Refugee and asylum-seeking women in Canada may have significant harmful childbearing health outcomes and unmet health and social care needs. The most vulnerable of these women are: those who have left their countries by force (e.g., war, rape or abuse histories), are separated from their families, have limited knowledge of the host country languages, and are visible minorities. Asylum-seekers face additional stresses related to their unknown future status and are marginalized with regards to access to provincial health care systems. The prevalence and severity of health issues in this population is not known nor is the extent of response from social service and health care systems (including variation in provincial service delivery). Understanding the magnitude of health and social concerns of newcomers requires data from a representative sample of childbearing refugee and asylum-seeking women resettling in Canada to permit comparisons to be made with non-refugee immigrant and Canadian-born women. Our research questions are: (1) Do refugee or asylum-seeking women and their infants, experience a greater number or a different distribution of harmful health events during pregnancy, at birth, and during the postpartum period than non-refugee immigrant or Canadian-born women? (2) Are the harmful health events experienced postpartum by asylum-seeking women and their infants, addressed less often (compared to refugees, non-refugee immigrants, and Canadian-born women) by the Canadian health care system as delivered in each of the three major receiving cities for newcomers?

Methods/design

This is a four-year multi-site prospective cohort study (pregnancy to 4 months postpartum). We will seek to recruit 2400 women [200 in each of 4 groups (refugees, asylum-seekers, non-refugee immigrants, and Canadian-born) from 1 of 12 postpartum hospital units across the 3 largest receiving cities for newcomers to Canada – Montreal, Toronto, and Vancouver].

Discussion

Knowledge of the extent of harmful health events occurring to asylum-seeking, refugee, immigrant, and Canadian-born women, and the response of the health care system to those events and group differences, if they exist, will inform immigration and health policy makers as well as providers of services.  相似文献   
248.
Cross-sectional studies in younger adults have demonstrated a positive association between energy intake (EI) and fat-free mass (FFM), with this relationship seemingly mediated by resting metabolic rate (RMR). Establishing a causal effect longitudinally would be prudent in older adults suffering from loss of appetite. We investigated the effects of FFM on RMR, appetite and EI in 39 healthy older adults (age: 66 ± 4 years, BMI: 25.1 ± 3.5 kg∙m2) assigned to either 12-week resistance training + protein supplementation group (RT + PRO) or control group (CON). Body composition, subjective appetite, leptin, insulin, RMR and laboratory-measured ad libitum EI were measured at baseline, weeks 6 and 12 of the intervention, while daily EI at baseline and week 12. FFM (+1.2 kg; p = 0.002), postprandial subjective appetite (+8 mm; p = 0.027), ad libitum EI (+119 kcal; p = 0.012) and daily EI (+133 kcal; p = 0.010) increased from baseline to week 12 in the RT + PRO. RMR, fasted subjective appetite, leptin and insulin concentrations remained unchanged (all p > 0.05). The increases ad libitum EI correlated with increases in FFM (r = 0.527, p = 0.001), with 54% of the change in EI attributed to FFM changes. In conclusion, FFM increases were associated with an increased ad libitum EI and postprandial appetite in older adults.  相似文献   
249.
The purpose of the current study was to identify predictors of delay discounting among adolescents receiving treatment for marijuana abuse or dependence, and to test delay discounting as a predictor of treatment outcome. Participants for this study were 165 adolescents (88% male) between the ages of 12 and 18 (mean age = 15.8 years; standard deviation = 1.3 years) who enrolled in a clinical trial comparing three behavioral treatments for adolescent marijuana abuse or dependence. Participants completed a delay discounting task at treatment onset for $100 and $1,000 of hypothetical money and marijuana. Overall, smaller magnitude rewards were discounted more than larger magnitude rewards. Delay discounting rates were concurrently related to demographic variables (socioeconomic status, race). Delay discounting of $1,000 of money predicted during treatment abstinence outcomes among adolescent marijuana abusers, over and above the effects of type of treatment received. Teens who show higher levels of discounting of the future may be an important subgroup to identify at treatment onset. Youth with a greater tendency to discount the future may require different intervention strategies that address their impulsivity (e.g., targeting executive function or inhibitory control) and/or different schedules of reinforcement to address their degree of preference for immediate rewards.  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