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   2786篇
  免费   151篇
  国内免费   14篇
耳鼻咽喉   105篇
儿科学   46篇
妇产科学   39篇
基础医学   390篇
口腔科学   52篇
临床医学   257篇
内科学   590篇
皮肤病学   40篇
神经病学   235篇
特种医学   117篇
外科学   431篇
综合类   11篇
预防医学   263篇
眼科学   56篇
药学   180篇
肿瘤学   139篇
  2023年   23篇
  2022年   50篇
  2021年   83篇
  2020年   59篇
  2019年   69篇
  2018年   72篇
  2017年   58篇
  2016年   67篇
  2015年   61篇
  2014年   67篇
  2013年   145篇
  2012年   205篇
  2011年   161篇
  2010年   80篇
  2009年   118篇
  2008年   180篇
  2007年   170篇
  2006年   166篇
  2005年   155篇
  2004年   149篇
  2003年   144篇
  2002年   111篇
  2001年   40篇
  2000年   33篇
  1999年   38篇
  1998年   26篇
  1997年   34篇
  1996年   16篇
  1995年   18篇
  1994年   21篇
  1993年   22篇
  1992年   16篇
  1991年   21篇
  1990年   21篇
  1989年   21篇
  1988年   16篇
  1987年   13篇
  1986年   21篇
  1985年   20篇
  1984年   14篇
  1983年   16篇
  1982年   20篇
  1981年   16篇
  1980年   9篇
  1979年   13篇
  1978年   9篇
  1977年   8篇
  1973年   7篇
  1972年   7篇
  1971年   8篇
排序方式: 共有2951条查询结果,搜索用时 250 毫秒
91.
Sixteen distally-based peroneus brevis muscle flaps were used to cover soft tissue defects in the lateral side of the ankle. The defect in 13 cases was on the lateral malleolus, in two on the lateral side of the calcaneus, and in one case in the Achilles tendon. The patients were all followed up until full recovery (mean 7.6 months, range 1.5–22 months). One flap failed to cover the defect and was replaced with a microvascular latissimus dorsi flap. In three cases minor revision and new skin grafting of the distal end of the flap was necessary. In 15 of the 16 patients the distally-based peroneus brevis muscle was successful in covering the lateral defect in the ankle. The technique of harvesting a flap is reliable, fast, and the overall success of the flap is good. The flap is particularly suitable for covering small or moderate sized defects on the lateral malleolus.  相似文献   
92.
The aim of this study was to investigate the prevalence of mental disorder and associated factors during an economic recession. Random samples of Finnish general population were collected in 3 consecutive years, 1993-95. The prevalence of mental disorders was assessed by means of the 12-item General Health Questionnaire (GHQ). The prevalence of mental disorders varied among Finnish men from 15.6% to 19.2% and among women from 21 to 24.5%. Mental disorder was more common among women than among men in every study year. Mental disorder was more common among the unemployed than among other respondents both in women and men in every year. Subjective poor health, suicidal thoughts and poor economic situation were constantly associated with mental disorder in both sexes every year. Using logistic regression analyses, problems with a partner, uncertain future orientation and use of psychoactive drugs, in particular, were found to be fairly permanent independent risk factors in relation to mental disorder. As studied by gender no major changes occurred in the mental health status of Finns during economic recession, although in many specific groups mental disorder was markedly more common than in the general population.  相似文献   
93.
The objective of this population-based study was to determine whether traumatic experiences in general, and multiple traumatic experiences in particular, are associated with persistent self-rated depressive symptoms in adult Finnish subjects over 2?years of follow-up. The study sample included 1405 subjects aged 25–64?years. Subjects (n=217) who were depressed both at baseline in 1999 and on follow-up 2?years later in 2001 (having persistent depressive symptoms) were compared with subjects (n=987) having no depressive symptoms either at baseline or on follow-up. All six categories of traumatic experiences (wartime experience, natural disaster, life-threatening accident, victim of violent crime, domestic violence and childhood sexual abuse) pertained to the respondents’ whole life span. Odds ratios, adjusted for significant covariates, were obtained from multiple logistic regression models that estimated the likelihood of persistent depressive symptoms in different trauma categories. Persistent depressive symptoms had a significant positive graded relationship with the number of traumatic experiences. The adjusted odds of persistent depression was 6.05 (95% CI 1.76–20.7) for men and 6.99 (95% CI 2.69–18.2) for women in those with three or more traumatic experiences compared with those with no such experiences at all. Multiple traumatic experiences substantially increase the likelihood of persistent depressive symptoms. Mental health intervention, as early as possible, may serve to prevent the chronicity of depressive reactions among victims of multiple traumas.  相似文献   
94.
Background

There is evidence that prenatal stress and smoking during pregnancy both independently increase the risk of offspring psychopathology. Here we examine whether increased levels of self-reported stress is associated with increased smoking in a population of pregnant women, and whether prenatal smoking is associated with offspring psychiatric diagnoses independent of prenatal stress exposure.

Method

Using a longitudinal birth cohort, we used ordered logistic regressions to examine associations between maternal stress and smoking during pregnancy. We then used logistic regression analyses to examine associations between prenatal smoking and later offspring psychiatric disorders.

Results

A dose–response relationship was found between maternally reported stress and smoking during pregnancy. Pregnant women reporting severe stress were more likely to smoke compared to both the moderate stress and no stress groups, and those reporting moderate stress were significantly more likely to smoke compared to the no stress group. Smoking more than 5 cigarettes daily during pregnancy increased the risk of offspring personality disorder (OR 3.08, 95% CI 1.60–5.94) as well as developing any Axis 1 psychiatric disorder, inclusive of mood, anxiety and psychotic disorders (OR 1.45, 95% CI 1.04–2.04). After adjusting for parental psychiatric history and maternal self-reported stress during pregnancy, associations between smoking more than 5 cigarettes daily when pregnancy and offspring personality (OR 2.58 95% CI 1.32–5.06) disorder remained.

Conclusion

Exposure to cigarette smoking during gestation could impact a child’s mental health. Smoking during pregnancy is a prime target for preventative interventions as unlike most other environmental risk factors, it is very amenable to change.

  相似文献   
95.
96.
97.
98.
BACKGROUND: Whole-grain rye and wheat cereals contain high amounts of alkylresorcinols (ARs), phenolic lipids. ARs can be quantified in plasma. Two recently identified urinary AR metabolites, 3,5-dihydroxyphenylbenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), may be useful as biomarkers of intake of whole-grain rye and wheat. METHODS: We evaluated 4 pretreatment protocols for quantifying urinary DHBA and DHPPA using HPLC coupled with a coulometric electrode array detector. Syringic acid was used as the internal calibrator. RESULTS: Measured urinary concentrations of DHBA and DHPPA were 0.8-115 micromol/L. The mean recoveries of all added concentrations were 85%-104% for DHBA and 86%-99% for DHPPA, depending on the degree of the purification. The protocol versions with less purification correlated well with the protocol including highest purification. The correlation coefficients (r(2)) were 0.9699-0.8153 for DHBA and 0.9854-0.8371 for DHPPA. CONCLUSION: Although the protocol with the most purification steps was most specific, all protocols were suitable for measuring DHBA and DHPPA in urine. The rapid protocol with simple hydrolysis could be used in large-scale clinical studies. Additional investigation is needed to clarify whether these metabolites are useful biomarkers of whole-grain intake and helpful in the exploration of its association with human diseases.  相似文献   
99.
100.
The change in augmentation index following salbutamol inhalation has been applied to evaluate endothelial function. We examined the contribution of salbutamol‐induced increase in heart rate to the observed decrease in augmentation index. Haemodynamics were recorded using whole‐body impedance cardiography and continuous pulse wave analysis from tonometric radial blood pressure. All subjects (n = 335, mean age 46, body mass index 26, 48% men) were without medications with cardiovascular influences. The effects of salbutamol inhalation (0.4 mg) versus the endothelium‐independent agent nitroglycerin resoriblet (0.25 mg) were examined during passive head‐up tilt, as the haemodynamic influences of these compounds depend on body position. Salbutamol decreased augmentation index by ~3‐4% units in supine and upright positions. Although salbutamol moderately increased cardiac index (+4.5%) and decreased systemic vascular resistance (?8.5%), the significant haemodynamic explanatory factors for decreased augmentation index in multivariate analysis were increased supine heart rate, and increased upright heart rate and decreased ejection duration (< 0.001 for all, r= 0.36–0.37). Sublingual nitroglycerin decreased supine and upright augmentation index by ~15% units and ~23% units, respectively. The haemodynamic explanatory factors for these changes in multivariate analysis were increased heart rate, reduced ejection duration and reduced systemic vascular resistance ( 0.021 for all, r2 = 0.22–0.34). In conclusion, the lowering influence of salbutamol on augmentation index may be largely explained by increased heart rate, suggesting that this effect may not predominantly reflect endothelial function.  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