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   1868篇
  免费   155篇
  国内免费   6篇
耳鼻咽喉   17篇
儿科学   111篇
妇产科学   148篇
基础医学   233篇
口腔科学   66篇
临床医学   227篇
内科学   277篇
皮肤病学   15篇
神经病学   157篇
特种医学   56篇
外科学   297篇
综合类   60篇
一般理论   2篇
预防医学   173篇
眼科学   14篇
药学   96篇
中国医学   4篇
肿瘤学   76篇
  2023年   11篇
  2022年   14篇
  2021年   47篇
  2020年   22篇
  2019年   48篇
  2018年   59篇
  2017年   40篇
  2016年   56篇
  2015年   49篇
  2014年   76篇
  2013年   79篇
  2012年   124篇
  2011年   116篇
  2010年   57篇
  2009年   66篇
  2008年   96篇
  2007年   72篇
  2006年   74篇
  2005年   62篇
  2004年   76篇
  2003年   69篇
  2002年   55篇
  2001年   48篇
  2000年   42篇
  1999年   36篇
  1998年   21篇
  1997年   30篇
  1996年   17篇
  1995年   16篇
  1994年   13篇
  1993年   15篇
  1992年   29篇
  1991年   26篇
  1990年   26篇
  1989年   39篇
  1988年   28篇
  1987年   30篇
  1986年   22篇
  1985年   39篇
  1984年   26篇
  1983年   9篇
  1981年   10篇
  1980年   8篇
  1979年   13篇
  1978年   11篇
  1974年   9篇
  1973年   11篇
  1972年   10篇
  1969年   9篇
  1966年   8篇
排序方式: 共有2029条查询结果,搜索用时 15 毫秒
1.

Objective

To examine the experience of interracial anxiety among health professionals and how it may affect the quality of their interactions with patients from racially marginalized populations. We explored the influence of prior interracial exposure—specifically through childhood neighborhoods, college student bodies, and friend groups—on interracial anxiety among medical students and residents. We also examined whether levels of interracial anxiety change from medical school through residency.

Data Source

Web-based longitudinal survey data from the Medical Student Cognitive Habits and Growth Evaluation Study.

Study Design

We used a retrospective longitudinal design with four observations for each trainee. The study population consisted of non-Black US medical trainees surveyed in their 1st and 4th years of medical school and 2nd and 3rd years of residency. Mixed effects longitudinal models were used to assess predictors of interracial anxiety and assess changes in interracial anxiety scores over time.

Principal Findings

In total, 3155 non-Black medical trainees were followed for 7 years. Seventy-eight percent grew up in predominantly White neighborhoods. Living in predominantly White neighborhoods and having less racially diverse friends were associated with higher levels of interracial anxiety among medical trainees. Trainees' interracial anxiety scores did not substantially change over time; interracial anxiety was highest in the 1st year of medical school, lowest in the 4th year, and increased slightly during residency.

Conclusions

Neighborhood and friend group composition had independent effects on interracial anxiety, indicating that premedical racial socialization may affect medical trainees' preparedness to interact effectively with diverse patient populations. Additionally, the lack of substantial change in interracial anxiety throughout medical training suggests the importance of providing curricular tools and structure (e.g., instituting interracial cooperative learning activities) to foster the development of healthy interracial relationships.  相似文献   
2.

Background

Most elderly trauma patients suffer blunt head injury and many utilize antithrombotic (AT) medications. The utility of delayed CT-head (D-CTH) in neurologically intact elderly patients using AT who have an intracranial hemorrhage (ICH) on presentation is unknown. We hypothesized that D-CTH would not alter clinical management and aimed to evaluate the role of D-CTH in this population.

Methods

A retrospective cohort study was performed. Patients ≥65 years sustaining blunt head injuries from January 2010 to July 2017 were identified using our level 1 trauma center database. AT-patients presenting with ICH who underwent D-CTH were included. Patients with worsened ICH were compared to those with stable to improved ICH on D-CTH. AT-patients were compared to a cohort of non-AT patients. Fisher’s Exact and Mann-Whitney U tests were utilized and a power analysis conducted.

Results

137?A?T and 34 non-AT patients were identified. There was no difference in hemorrhage progression or appearance of new ICH. No patient had a change in management from D-CTH in either cohort. AT-patients were slightly older (p?<?0.001), but cohorts were otherwise similar.50 AT-patients with worsened ICH were compared to 87 with stable ICH. There was no difference in cohort demographics. Hemorrhage progression did not vary with type of AT used but did increase if multiple types of synchronous ICH were present (p?<?0.001).

Conclusions

Our data supports abstaining from routine D-CTH of elderly ICH patients with an intact neurologic examination who are utilizing aspirin, clopidogrel or warfarin. Conclusions cannot be drawn regarding new oral anticoagulants (NOACs) given low enrollment. Further multicenter study is required to provide adequate power and detect small levels of management change.  相似文献   
3.
4.
5.
A case of sclerosing epithelioid fibrosarcoma and its appearance on MRI is presented. The tumor showed a zonal architecture on MRI with a large central core of very low signal intensity and a peripheral rim of intermediate to high signal intensity on T1- and T2-weighted spin echo pulse sequences. The core showed decreased cellularity with dense collagen deposition on histologic examination, and the peripheral zone increased cellularity with increased nuclear atypia. The presence of a prominent region of very low signal intensity on T1- and T2-weighted images can be seen with neural tumors, giant cell tumor of the tendon sheath, aggressive fibromatosis, and, in rare instances, with soft tissue sarcomas rich in collagen.  相似文献   
6.
J. Hull  P. Vervaart  K. Grimwood    P. Phelan 《Thorax》1997,52(6):557-560
BACKGROUND: It has been suggested that oxidative stress contributes to lung injury in cystic fibrosis. There is, however, no direct evidence of increased pulmonary oxidative stress in cystic fibrosis nor of the effects of inflammation on the major pulmonary antioxidant, glutathione. A study was undertaken to measure these parameters in infants and young children in the presence or absence of pulmonary inflammation. METHODS: Thirty two infants and young children with cystic fibrosis of mean (SD) age 21.4 (15.3) months (range 2-54) and seven non-cystic fibrosis control subjects of mean (SD) age 21.0 (21.2) months (range 2-54) were studied using bronchoalveolar lavage (BAL). On the basis of the BAL findings the cystic fibrosis group was divided into those with (CF-I) and those without pulmonary inflammation (CF- NI). Levels of lipid hydroperoxide, total glutathione, and gamma- glutamyl transpeptidase (gamma-GT) were then measured in the BAL fluid. RESULTS: The concentrations of lipid hydroperoxide and gamma-GT in the epithelial lining fluid were significantly increased in the CF-I group compared with the control and CF-NI groups, each of which had similar values for these parameters (ratio of geometric means for CF-I group versus control for lipid hydroperoxide 5.4 (95% confidence interval (CI) 1.8 to 15.8) and for gamma-GT 5.2 (95% CI 1.4 to 19.4)). The glutathione concentration tended to be lower in the CF-I subjects but the difference did not reach statistical significance. CONCLUSIONS: These results demonstrate that the airways in patients with cystic fibrosis are exposed to increased oxidative stress which appears to be a consequence of pulmonary inflammation rather than part of the primary cystic fibrosis defect. The increase in gamma-GT in the CF-I group suggests a mechanism by which extracellular glutathione could be utilised by airway epithelial cells.


  相似文献   
7.
8.
Autosomal dominant periodic fevers constitute a range of syndromes characterised by recurrent attacks of fever and abdominal pain. Familial Hibernian fever (FHF) has been described in only one United Kingdom based family, but two other Irish families have been found with similar clinical features. FHF resembles familial Mediterranean fever (FMF) in several clinical features, but the mode of inheritance of FHF is dominant whereas FMF is recessive. We have investigated whether autosomal dominant periodic fevers, in particular FHF, map to the FMF susceptibility locus (MEFV) on chromosome 16p13.3. We have used informative microsatellite markers flanking this locus to genotype members of the three families mentioned above. Two point and multipoint lod scores definitively excluded linkage to MEFV in the two larger families. A haplotype study confirmed these findings, indicating that FHF is genotypically as well as phenotypically distinct from FMF.  相似文献   
9.
OBJECTIVES: To assess the influence of education on the association between apolipoprotein E and cognitive change. DESIGN: Prospective cohort. PARTICIPANTS: HMO-based sample of 2168 non-demented community-dwelling elderly followed over 6 years. MEASUREMENTS: Generalized estimating equations were used with the difference between baseline and follow-up cognitive abilities screening instrument (CASI) as the outcome variable. RESULTS: At follow-up, 6% of the sample had a decline of 1.5 S.D. or greater on the CASI. Compared to individuals without an APOE4 allele, individuals with a single APOE4 allele did not have greater CASI decline. By contrast, individuals with two APOE4 alleles experienced greater decline in cognitive performance and the magnitude of that decline decreased as years of educational attainment increased. These relationships held after adjusting for age, gender, ethnicity, depression, diabetes, and history of vascular disease. CONCLUSION: Lower education was associated with steep 4-year cognitive decline for APOE4 homozygotes but not for APOE4 heterozygotes. Potentially modifiable host factors such as education could influence the association of high-risk genotypes and cognitive decline.  相似文献   
10.
PURPOSE: Studies have shown that medical students become more cynical and less altruistic as they advance in training. However, these studies were conducted in traditional medical schools, and many used unvalidated tools. This study examined students' attitudes in a problem-based learning (PBL) curriculum using reliable and valid measures. METHOD: Medical students and PGY-1 residents at Mercer University School of Medicine in Macon, Georgia, completed Wrightsman's Philosophies of Human Natures Scale (PHNS) in 1999 and 2000. Chronbach's alpha assessed internal reliability among subscales, and test-retest reliability coefficients confirmed acceptable reliability. For 114 students who completed both surveys, changes in PHNS scores were analyzed, with particular attention to the subscales of trustworthiness, altruism, and cynicism. RESULTS: Students assessed at the beginning of their second year increased the extent to which they believed people are trustworthy and increased their beliefs in how altruistic people are. They also showed a significant decrease in cynicism. There was not a significant change in trustworthiness, altruism, or cynicism among the participants beyond first year. In general, female students held less cynical views about others and believed people to be more trustworthy. CONCLUSIONS: Contrary to prior reports, this study found that more advanced trainees were not more cynical or less altruistic than their more junior counterparts. Indeed, a significant and positive change of attitudes among the participants during their first year of medical school refuted earlier reports. Thus, results of earlier studies and the effect of a PBL curriculum on attitudes of medical students need to be re-examined.  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