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   1938篇
  免费   135篇
  国内免费   6篇
耳鼻咽喉   6篇
儿科学   49篇
妇产科学   31篇
基础医学   232篇
口腔科学   27篇
临床医学   276篇
内科学   365篇
皮肤病学   43篇
神经病学   219篇
特种医学   119篇
外科学   178篇
综合类   47篇
一般理论   3篇
预防医学   192篇
眼科学   19篇
药学   131篇
中国医学   5篇
肿瘤学   137篇
  2023年   14篇
  2022年   44篇
  2021年   79篇
  2020年   44篇
  2019年   69篇
  2018年   64篇
  2017年   43篇
  2016年   43篇
  2015年   56篇
  2014年   57篇
  2013年   100篇
  2012年   84篇
  2011年   106篇
  2010年   37篇
  2009年   57篇
  2008年   84篇
  2007年   62篇
  2006年   71篇
  2005年   53篇
  2004年   68篇
  2003年   65篇
  2002年   56篇
  2001年   42篇
  2000年   49篇
  1999年   32篇
  1998年   24篇
  1997年   30篇
  1996年   24篇
  1995年   24篇
  1994年   15篇
  1993年   14篇
  1992年   39篇
  1991年   23篇
  1990年   38篇
  1989年   46篇
  1988年   29篇
  1987年   26篇
  1986年   27篇
  1985年   36篇
  1984年   23篇
  1983年   14篇
  1982年   13篇
  1981年   16篇
  1979年   10篇
  1978年   11篇
  1977年   18篇
  1975年   11篇
  1971年   9篇
  1969年   8篇
  1967年   9篇
排序方式: 共有2079条查询结果,搜索用时 15 毫秒
51.
PURPOSE: We investigated the role of race in predicting the likelihood of using hospice and dying in a hosptial among dual-eligible (Medicare and Medicaid) nursing home residents. DESIGN AND METHODS: This follow-back cohort study examined factors associated with hospice use and in-hospital death among non-Hispanic Black and non-Hispanic White dual-eligible nursing home residents (N = 30,765) who died in Florida during one of three years: 2000, 2001, or 2002. We used logistic regression models to identify independent predictors of hospice use and in-hospital death. RESULTS: After we controlled for other factors, Black residents were significantly less likely to use hospice and more likely to die in a hospital. Principal cause of death moderated the relationship between race and hospice use: Black residents were significantly less likely to use hospice than White residents among residents without cancer as principal cause of death, but there was no difference among residents with cancer as cause of death. Further analyses for each racial group revealed that the impact of cause of death in predicting hospice use was greater among Black residents than White residents. IMPLICATIONS: Hospice care offers many benefits, including reduced risk of in-hospital death, but Black nursing home residents are less likely to use hospice and may have different perceptions of need for hospice care compared with White residents. Future research and outreach efforts should focus on developing culturally sensitive, disease-focused end-of-life education and communication interventions that target residents, families, nursing home providers, and physicians.  相似文献   
52.
53.
54.
55.
OBJECTIVE: To examine whether promoter polymorphisms associated with variation in interleukin-10 (IL-10) production are relevant to the development of rheumatoid arthritis (RA) or Felty's syndrome (FS). METHODS: DNA was obtained from 44 FS patients, 117 RA patients and 295 controls. The promoter region between -533 and - 1120 was amplified by polymerase chain reaction, and polymorphisms detected by restriction enzyme digest or sequence-specific oligonucleotide probing. RESULTS: We found no significant difference in allele or haplotype frequencies between the groups. CONCLUSION: There is no association between FS or RA and these recently identified IL-10 promoter polymorphisms. Other genetic or environmental factors could explain the alterations in IL-10 levels seen in these conditions.   相似文献   
56.
ABSTRACT

Introduction: Treatment options for COPD have evolved rapidly in the last decade and inhaled bronchodilators have largely supplanted the use of oral bronchodilators because of their increased efficacy and excellent safety with topical delivery to the lung. Recently added to the therapeutic armamentarium are fixed-dose combinations (FDC) of two long acting bronchodilators. LAMAs (long acting muscarinic antagonists) and LABAs (long acting beta agonists) are the main classes available and use different pathways to effectively produce bronchial smooth muscle relaxation.

Areas covered: The most recent inhaled FDC LAMA/LABA to come to market is Aclidinium Bromide and Formoterol Fumarate. We searched databases of PubMed, Cochrane Library, and manufacturers’ websites and retrieved all the randomized-controlled trials (RCTs) conducted with these drugs up to September 2019.

Expert opinion: It is likely that FDCs will become the core of our COPD pharmacotherapy for all but the mildest COPD patients. These individual drugs have excellent efficacy and safety records for the maintenance treatment of COPD. Studies have demonstrated that twice daily treatment with aclidinium/formoterol resulted in significant improvement in lung function and an improved exercise tolerance when compared to placebo. Adverse effects are within the range of what is seen with other LAMA/LABA combinations.  相似文献   
57.
Engagement in regular aerobic exercise is associated with cognitive benefits, but information on the mechanisms governing these changes in humans is limited. The goal of the current study was to compare neurometabolite concentrations relating to cellular metabolism, structure, and viability in endurance-trained and sedentary middle-aged adults. Twenty-eight endurance-trained and 27 sedentary adults, aged 40–65 years, underwent general health assessment, cardiorespiratory fitness measurement, neuropsychological testing, and proton magnetic resonance spectroscopy (1H MRS). 1H MRS was used to examine N-acetyl-aspartate (NAA), creatine (Cr), myo-inositol (mI), choline (Cho), and glutamate (Glu) concentrations in frontal and occipitoparietal grey matter. Group differences in concentrations of NAA, Cho, mI, and Glu, calculated as ratios over Cr, were explored using ANOVA. There were no significant differences in global cognitive function, memory, and executive function performance between the groups. In comparison to sedentary adults, the endurance-trained group displayed significantly higher NAA/Cr in the frontal grey matter (F(1, 53) = 5.367, p = 0.024) and higher Cho/Cr in the occipitoparietal grey matter (F(1, 53) = 5.138, p = 0.028). Within our middle-aged sample, endurance-trained adults demonstrated higher levels of NAA/Cr in the frontal grey matter and higher Cho/Cr in the occipitoparietal grey matter. Higher levels of NAA may indicate greater neuronal integrity and higher cerebral metabolic efficiency in association with cardiorespiratory fitness, whereas increased Cho may represent increased phospholipid levels secondary to neural plasticity.  相似文献   
58.
59.
The purpose of this study is to investigate the applicability of the current surgical guideline stating that the main facial foramina that transmit cutaneous nerves to the face (supraorbital notch/foramen, infraorbital foramen, and mental foramen) are equidistant from the midline in European and Hispanic populations. Previous studies suggest this surgical guideline is not applicable for all ethnicities; however, to our knowledge, no data have been published regarding the accuracy of this guideline pertaining to the Hispanic population. An experimental study was performed on 67 cadavers donated to the Human Anatomy Program at UT Health San Antonio. The supraorbital, infraorbital, and mental foramina were dissected and midline structures including the crista galli, internasal suture, anterior nasal spine, and mandibular symphysis were identified. The distance from each foramen to midline was recorded using a digital caliper. For all cadavers/ethnicities studied, the supraorbital, infraorbital, and mental foramina were 25.32 mm, 29.57 mm, and 25.55 mm to the midline, respectively. Thus, the infraorbital foramen is located significantly more lateral compared to the supraorbital (p < 0.0001) and mental foramina (p < 0.0001). After dividing the sample based on ethnicity, this relationship was also true for the European sample and tended to be true for the Hispanic sample. Significant anatomical variations exist in the current surgical guideline stating that the supraorbital foramen, infraorbital foramen, and mental foramen are equidistant from the midline. Clinicians may need to adjust their methodology during surgical procedures of the face in order to optimize patient care.  相似文献   
60.
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