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   1513篇
  免费   116篇
  国内免费   4篇
耳鼻咽喉   6篇
儿科学   98篇
妇产科学   59篇
基础医学   213篇
口腔科学   10篇
临床医学   91篇
内科学   312篇
皮肤病学   46篇
神经病学   209篇
特种医学   28篇
外科学   208篇
综合类   26篇
预防医学   107篇
眼科学   103篇
药学   67篇
中国医学   2篇
肿瘤学   48篇
  2021年   20篇
  2020年   13篇
  2019年   26篇
  2018年   29篇
  2017年   15篇
  2016年   21篇
  2015年   23篇
  2014年   19篇
  2013年   35篇
  2012年   72篇
  2011年   63篇
  2010年   29篇
  2009年   31篇
  2008年   65篇
  2007年   66篇
  2006年   71篇
  2005年   63篇
  2004年   65篇
  2003年   51篇
  2002年   43篇
  2001年   52篇
  2000年   45篇
  1999年   42篇
  1998年   17篇
  1996年   13篇
  1995年   18篇
  1993年   11篇
  1992年   33篇
  1991年   22篇
  1990年   42篇
  1989年   32篇
  1988年   30篇
  1987年   26篇
  1986年   15篇
  1985年   24篇
  1984年   21篇
  1983年   16篇
  1982年   19篇
  1980年   11篇
  1979年   27篇
  1978年   13篇
  1977年   17篇
  1976年   20篇
  1975年   18篇
  1974年   16篇
  1973年   21篇
  1971年   11篇
  1969年   15篇
  1968年   13篇
  1967年   12篇
排序方式: 共有1633条查询结果,搜索用时 0 毫秒
11.
12.
We found that an abnormal hemoglobin with a very low oxygen affinity was responsible for overt cyanosis in an otherwise healthy adolescent. Hemoglobin Beth Israel, in which serine replaces the asparagine residue normally present at position 102 (G4) of the beta-polypeptide chain, was associated with normal blood counts and no apparent exercise intolerance in the heterozygous carrier. Cyanosis resulted from a drastically right-shifted oxygen dissociation curve, whose position and shape could account for the absence of "physiologic" anemia. The whole-blood oxygen tension at 50 per cent oxygen saturation was 88 mm Hg (normally 26 +/- 1 mm Hg), and the arterial blood was only 63 per cent saturated with oxygen despite a normal oxygen tension of 97 mm Hg. The hemolysate showed a low oxygen affinity but normal Bohr effect. Unexplained cyanosis, particularly in association with normal arterial oxygen tension should prompt a search for an abnormal hemoglobin, which may obviate the need for invasive diagnostic procedures.  相似文献   
13.
Postprandial hyperglycemia (PPHG) is strongly linked with the future development of cardiovascular complications in type 2 diabetes (T2D). Hence, reducing postprandial glycemic excursions is essential in T2D treatment to slow progressive deficiency of β-cell function and prevent cardiovascular complications. Most of the metabolic processes involved in PPHG, i.e., β-cell secretory function, GLP-1 secretion, insulin sensitivity, muscular glucose uptake, and hepatic glucose production, are controlled by the circadian clock and display daily oscillation. Consequently, postprandial glycemia displays diurnal variation with a higher glycemic response after meals with the same carbohydrate content, consumed at dusk compared to the morning. T2D and meal timing schedule not synchronized with the circadian clock (i.e., skipping breakfast) are associated with disrupted clock gene expression and is linked to PPHG. In contrast, greater intake in the morning (i.e., high energy breakfast) than in the evening has a resetting effect on clock gene oscillations and beneficial effects on weight loss, appetite, and reduction of PPHG, independently of total energy intake. Therefore, resetting clock gene expression through a diet intervention consisting of meal timing aligned to the circadian clock, i.e., shifting most calories and carbohydrates to the early hours of the day, is a promising therapeutic approach to improve PPHG in T2D. This review will focus on recent studies, showing how a high-energy breakfast diet (Bdiet) has resetting and synchronizing actions on circadian clock genes expression, improving glucose metabolism, postprandial glycemic excursions along with weight loss in T2D.  相似文献   
14.
15.
BACKGROUND: AbobotulinumtoxinA (AboBoNT-A; Dysport®; Ipsen, Boulogne-Billancourt, France/Azzalure®; Galderma, Lausanne, Switzerland) is a botulinum neurotoxin type A approved for aesthetic use in the treatment of glabellar lines in adult patients under 65 years in Europe, the United States, and other countries. OBJECTIVE: We sought to analyze current literature on patient satisfaction with aboBoNT-A for upper facial aesthetic indications. METHODS: A systematic review of literature databases (PubMed/MEDLINE, Embase, the Cochrane Library, and Google Scholar) was performed to identify English-language publications reporting on patients with aesthetic indications (including glabellar lines and wrinkles) receiving aboBoNT-A, that assessed patient and/or physician satisfaction with treatment, with no restrictions on comparator studies. Structured data extraction was used to enable inter-study analysis. A post-hoc analysis was also performed to assess patient satisfaction by sex and age, using results from the noninterventional APPEAL study of patients’ satisfaction with aboBoNT-A for treating glabellar lines. RESULTS: Overall, 22 original research papers were identified. Patient satisfaction rates for aboBoNT-A treatment were significantly higher versus placebo from two weeks to between three and five months postinjection. At two to three weeks postinjection, patient satisfaction rates were 52% and 99% across studies. In studies with later time points, patient satisfaction rates were 85 to 87 percent at 5 months and between 25 and 100 percent at 6 months post-injection. Physician satisfaction was also high (97%–100%, across three treatments). No notable differences in patient satisfaction by sex or age were observed in the APPEAL study. CONCLUSION: High rates of patient satisfaction have been achieved with aboBoNT-A treatment for upper facial aesthetic indications. Despite the current recommended interval of ≥12 weeks, satisfaction with the aesthetic results of aboBoNT-A therapy is still evident up to 6 months post-injection in some patients.  相似文献   
16.
A harm reduction approach to alcohol and substance abuse is becoming increasingly popular as an alternative to prohibitionist and abstentionist policies. It is seen as particularly valuable for some high-risk populations, such as injection drug users and street youth. A strong argument can be made that Aboriginal communities in Ontario, Canada, and probably across the country, are appropriate environments for a harm reduction approach. Aboriginal people are at extremely elevated risk for accident, illness and death. At the same time, alcohol use is a predominant factor in many of these outcomes, and elevates many of the risks associated with Aboriginal life. Isolated, remote reserve communities in northern Ontario present additional risks of extremely poor living conditions and extreme weather conditions. Prohibition and abstinence are currently the main approaches to alcohol and substance abuse in many of these communities, while the role of alcohol in morbidity, mortality and other social problems remains high. There are positive indications that the feasibility of harm reduction strategies could be broached in some communities. It is concluded that the obstacles are significant but a community-by-community approach is a strong feature of harm reduction, and may increase its prospects for piloting strategies in individual communities.  相似文献   
17.
Three visual manifestations of Gilles de la Tourette syndrome (TS), a neuropsychiatric disorder, have been previously reported. In this paper we report anomalies in the measured kinetic paracentral visual field of TS patients and their family members. We found that 96% of TS patients exhibited paracentral kinetic visual field defects (nasal and temporal steps, enlargement, "ringing," and/or baring of the blind spot). Ninety-three percent of fathers of TS children and, surprisingly, about 80% of mothers exhibit these characteristic visual field anomalies. Sample data and examples of family studies are reported.  相似文献   
18.
19.
20.
AIM: To examine the relation between the duration of breast feeding and morbidity as a result of respiratory illness and infection in the first year of life. METHODS: Prospective birth cohort study of 2602 live born children ascertained through antenatal clinics at the major tertiary obstetric hospital in Perth, Western Australia. Main outcome measures were hospital, doctor, or clinic visits, and hospital admissions for respiratory illness and infection in the first year of life. Main exposure measures were the duration of predominant breast feeding (defined as the age other milk was introduced) and partial (any) breast feeding (defined as the age breast feeding was stopped). Main confounders were gender, gestational age less than 37 weeks, smoking in pregnancy, older siblings, maternal education, and maternal age. RESULTS: Hospital, doctor, or clinic visits for four or more upper respiratory tract infections were significantly greater if predominant breast feeding was stopped before 2 months or partial breast feeding was stopped before 6 months. Predominant breast feeding for less than six months was associated with an increased risk for two or more hospital, doctor, or clinic visits and hospital admission for wheezing lower respiratory illness. Breast feeding for less than eight months was associated with a significantly increased risk for two or more hospital, doctor, or clinic visits or hospital admissions because of wheezing lower respiratory illnesses. CONCLUSIONS: Predominant breast feeding for at least six months and partial breast feeding for up to one year may reduce the prevalence and subsequent morbidity of respiratory illness and infection in infancy.  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