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   613篇
  免费   66篇
耳鼻咽喉   8篇
儿科学   17篇
妇产科学   55篇
基础医学   79篇
口腔科学   1篇
临床医学   93篇
内科学   84篇
皮肤病学   9篇
神经病学   36篇
特种医学   8篇
外科学   70篇
综合类   2篇
预防医学   117篇
眼科学   8篇
药学   41篇
中国医学   2篇
肿瘤学   49篇
  2023年   1篇
  2022年   10篇
  2021年   11篇
  2020年   7篇
  2019年   16篇
  2018年   18篇
  2017年   8篇
  2016年   13篇
  2015年   9篇
  2014年   26篇
  2013年   47篇
  2012年   78篇
  2011年   61篇
  2010年   24篇
  2009年   41篇
  2008年   49篇
  2007年   47篇
  2006年   40篇
  2005年   40篇
  2004年   27篇
  2003年   37篇
  2002年   26篇
  2001年   1篇
  2000年   3篇
  1999年   2篇
  1998年   6篇
  1997年   4篇
  1996年   2篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1973年   2篇
  1972年   1篇
  1970年   1篇
  1887年   1篇
排序方式: 共有679条查询结果,搜索用时 10 毫秒
21.

Background

Health risk assessments are becoming more popular as a tool to conveniently and effectively reach community-dwelling adults who may be at risk for serious chronic conditions such as coronary heart disease (CHD). The use of such instruments to improve adults’ risk factor awareness and concordance with clinically measured risk factor values could be an opportunity to advance public health knowledge and build effective interventions.

Objective

The objective of this study was to determine if an Internet-based health risk assessment can highlight important aspects of agreement between respondents’ self-reported and clinically measured CHD risk factors for community-dwelling adults who may be at risk for CHD.

Methods

Data from an Internet-based cardiovascular health risk assessment (Heart Aware) administered to community-dwelling adults at 127 clinical sites were analyzed. Respondents were recruited through individual hospital marketing campaigns, such as media advertising and print media, found throughout inpatient and outpatient facilities. CHD risk factors from the Framingham Heart Study were examined. Weighted kappa statistics were calculated to measure interrater agreement between respondents’ self-reported and clinically measured CHD risk factors. Weighted kappa statistics were then calculated for each sample by strata of overall 10-year CHD risk. Three samples were drawn based on strategies for treating missing data: a listwise deleted sample, a pairwise deleted sample, and a multiple imputation (MI) sample.

Results

The MI sample (n=16,879) was most appropriate for addressing missing data. No CHD risk factor had better than marginal interrater agreement (κ>.60). High-density lipoprotein cholesterol (HDL-C) exhibited suboptimal interrater agreement that deteriorated (eg, κ<.30) as overall CHD risk increased. Conversely, low-density lipoprotein cholesterol (LDL-C) interrater agreement improved (eg, up to κ=.25) as overall CHD risk increased. Overall CHD risk of the sample was lower than comparative population-based CHD risk (ie, no more than 15% risk of CHD for the sample vs up to a 30% chance of CHD for the population).

Conclusions

Interventions are needed to improve knowledge of CHD risk factors. Specific interventions should address perceptions of HDL-C and LCL-C. Internet-based health risk assessments such as Heart Aware may contribute to public health surveillance, but they must address selection bias of Internet-based recruitment methods.  相似文献   
22.
ObjectivesTo determine the prevalence of burnout among the midwifery workforce and the association between fixed personal and practice characteristics and modifiable organizational factors, specifically practice environment, to burnout among midwives in the United States.Data SourcePrimary data collection was conducted via an online survey of the complete national roster of certified nurse‐midwives and certified midwives over 3 weeks in April 2017.Study DesignThe study was a cross‐sectional observational survey consisting of 95 items about personal and practice characteristics, respondents'' practice environments, and professional burnout.Data Collection MethodsThe inclusion criterion was actively practicing midwifery in the United States. Data were analyzed with bivariate analyses to determine the association between personal and practice characteristics and burnout. A hierarchal multilinear regression evaluated the interrelationship between personal and practice characteristics, practice environment, and burnout.Principal FindingsOf the almost one third (30.9%) of certified nurse‐midwives and certified midwives who responded to the survey, 40.6% met criteria for burnout. Weak negative correlations existed between burnout and indicators of career longevity: age (r(2256) = −0.09, p < 0.01), years as a midwife (r(2267) = −0.07, p = 0.01), and years with employer (r(2271) = −0.05, p = 0.02). There were significant relationships between burnout score and patient workload indicators: patients per day in outpatient setting (F(5,2292) = 13.995, p < 0.01), birth volume (F(3,1864) = 8.35, p < 0.01), and patient acuity (F(2,2295) = 20.21, p < 0.01). When the practice environment was entered into the model with personal and practice characteristics, the explained variance increased from 6.4% to 26.5% (F(20,1478) = 27.98, p < 0.01).ConclusionsOur findings suggested that a key driver of burnout among US midwives was the practice environment, specifically practice leadership and participation and support for the midwifery model of care. Structural and personal characteristics contributed less to burnout score than the practice environment, implying that prevention of burnout may be achieved through organizational support and does not require structural changes to the provision of perinatal health.  相似文献   
23.
Background and PurposeAnterior cruciate ligament injuries are prevalent among the athletic population, imposing a heavy economic burden, and the risk of re-injury. Most current biomechanical screening tasks are performed in the sagittal plane, and there is a need for more screening tools that assess sports specific movements in the frontal plane. The purpose of this study was to determine the reliability of and examine differences between sexes in the performance of the Lateral Bound Test (LBT).Materials/MethodsEach subject performed three trials of a LBT which included jumping laterally from one leg over a hurdle and landing on the opposite leg. Two cameras were placed six feet from the landing marker. Maximum dynamic knee valgus using the frontal plane projection angle and knee flexion angle at initial contact and maximal knee flexion were measured upon landing leg using 2D video analysis software. Additionally, video of 10 individuals’ trials were analyzed twice with one week between the analyses to obtain intra-rater reliability while 12 participants were retested one week later to determine test-retest reliability.ResultsThirty healthy subjects, 16 males, 14 females participated. Intra-rater reliability was determined to be excellent for all variables (ICC>0.96). In contrast, the test-retest reliability had greater disparity. Test-retest reliability ranged from poor (ICC = 0.47) to excellent (ICC > 0.90). Significant differences existed between the sexes, including males being significantly taller, weighing more, and demonstrating greater bilateral dynamic knee valgus (p < 0.05). No significant differences existed between sexes for knee flexion angles.ConclusionThe new LBT had excellent intra-rater reliability for assessing dynamic knee valgus and initial and maximum knee flexion angle when performing a functional movement in the frontal plane. Furthermore, males landed with more dynamic knee valgus than females which is contradictory to what has been observed with functional screening tools performed in the sagittal plane.Level of Evidence3b (reliability study)  相似文献   
24.
OBJECTIVES: Studies of tertiary cytoreductive surgery (TCS) in recurrent epithelial ovarian cancer are limited, and appropriate patient selection remains a clinical challenge. We sought to evaluate the impact of TCS on survival and to determine predictors of optimal tertiary resection. METHODS: Between January 1997 and July 2004, 47 women with recurrent epithelial ovarian cancer underwent TCS at two institutions. All patients received initial platinum and taxane-based chemotherapy following primary cytoreductive surgery. Clinico-pathologic factors and survival were retrospectively abstracted from medical records. Optimal TCS was defined as microscopic residual disease. RESULTS: Thirty of 47 (64%) patients underwent optimal TCS. Size of tumor implants<5 cm on preoperative imaging was the only significant predictor of achieving optimal TCS. Overall survival after TCS was statistically longer in patients with microscopic versus macroscopic residual disease (24 versus 16 months, p=0.03). After controlling for age, time to progression and optimal TCS, only the presence of diffuse disease at tertiary exploration remained a significant poor predictor of survival. However, in a cohort of patients with limited disease implants, multivariate analysis indicated that optimal TCS retained prognostic significance as a positive predictor of survival. Twelve patients (26%) experienced severe postoperative complications, including six with pulmonary embolism, four with fistulae and two with postoperative myocardial infarctions. CONCLUSIONS: Size of disease implants on preoperative imaging may guide the selection of candidates for TCS. In those patients with limited disease implants at laparotomy, optimal TCS is associated with improved survival.  相似文献   
25.
26.
27.

Background

Delayed-release dimethyl fumarate (DR-DMF) has cytoprotective and antiinflammatory properties and has recently been approved in the United States as an oral treatment for relapsing forms of multiple sclerosis. The most common adverse events associated with DR-DMF are flushing and gastrointestinal (GI) events, the incidences of which diminish over time.

Objective

The purpose of this study was to evaluate the tolerability and pharmacokinetic (PK) profile of DR-DMF with or without concomitant acetylsalicylic acid (aspirin), a cyclooxygenase inhibitor.

Methods

Healthy volunteers (N = 56) were randomized to receive different dosing regimens of DR-DMF or matching placebo with or without pretreatment with 325 mg aspirin for 4 days. Plasma levels of the active metabolite monomethyl fumarate were assessed on days 1 and 4. Flushing and GI events were assessed using patient-reported scales. Potential flushing mediators were explored.

Results

DR-DMF showed a safety, tolerability, and PK profile consistent with previous clinical experience, with no evidence of accumulation. Pretreatment with aspirin had no effect on the primary PK parameters, AUC0–10h, or Cmax. Flushing severity, assessed by 2 subject-reported rating scales, was generally mild and was rated highest at the start of treatment. Pretreatment with aspirin reduced flushing incidence and intensity without affecting GI events or the PK profile of DR-DMF. In some DR-DMF–treated individuals, plasma concentrations of a prostaglandin D2 (PGD2) metabolite were increased.

Conclusions

In healthy volunteers, DR-DMF was well tolerated over 4 days of dosing, with a PK profile consistent with that previously reported and no evidence of accumulation. Aspirin pretreatment reduced the incidence and intensity of flushing without affecting GI events or the DR-DMF PK profile. Elevated levels of PGD2 in some DR-DMF–treated individuals suggest that flushing may be, at least in part, prostaglandin mediated. ClinicalTrials.gov identifier: ID: NCT01281111.  相似文献   
28.
29.
30.
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