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   3281篇
  免费   26篇
  国内免费   7篇
耳鼻咽喉   14篇
儿科学   43篇
妇产科学   80篇
基础医学   280篇
口腔科学   78篇
临床医学   728篇
内科学   217篇
皮肤病学   16篇
神经病学   413篇
特种医学   579篇
外科学   425篇
综合类   23篇
预防医学   268篇
眼科学   17篇
药学   66篇
中国医学   26篇
肿瘤学   41篇
  2024年   2篇
  2023年   231篇
  2022年   468篇
  2021年   352篇
  2020年   400篇
  2019年   203篇
  2018年   89篇
  2017年   121篇
  2016年   144篇
  2015年   98篇
  2014年   292篇
  2013年   141篇
  2012年   68篇
  2011年   36篇
  2010年   126篇
  2009年   124篇
  2008年   33篇
  2007年   39篇
  2006年   38篇
  2005年   16篇
  2004年   17篇
  2003年   20篇
  2002年   24篇
  2001年   21篇
  2000年   18篇
  1999年   26篇
  1998年   25篇
  1997年   29篇
  1996年   27篇
  1995年   26篇
  1994年   14篇
  1993年   15篇
  1992年   4篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   13篇
排序方式: 共有3314条查询结果,搜索用时 215 毫秒
1.
We present an automated approach to detect and longitudinally track skin lesions on 3D total-body skin surface scans. The acquired 3D mesh of the subject is unwrapped to a 2D texture image, where a trained objected detection model, Faster R-CNN, localizes the lesions within the 2D domain. These detected skin lesions are mapped back to the 3D surface of the subject and, for subjects imaged multiple times, we construct a graph-based matching procedure to longitudinally track lesions that considers the anatomical correspondences among pairs of meshes and the geodesic proximity of corresponding lesions and the inter-lesion geodesic distances.We evaluated the proposed approach using 3DBodyTex, a publicly available dataset composed of 3D scans imaging the coloured skin (textured meshes) of 200 human subjects. We manually annotated locations that appeared to the human eye to contain a pigmented skin lesion as well as tracked a subset of lesions occurring on the same subject imaged in different poses. Our results, when compared to three human annotators, suggest that the trained Faster R-CNN detects lesions at a similar performance level as the human annotators. Our lesion tracking algorithm achieves an average matching accuracy of 88% on a set of detected corresponding pairs of prominent lesions of subjects imaged in different poses, and an average longitudinal accuracy of 71% when encompassing additional errors due to lesion detection. As there currently is no other large-scale publicly available dataset of 3D total-body skin lesions, we publicly release over 25,000 3DBodyTex manual annotations, which we hope will further research on total-body skin lesion analysis.  相似文献   
2.
3.
4.
BackgroundRocker sole (RS) shoes have been linked to impaired postural control. However, which features of RS design affect balance is unclear.Research questionWhich RS design features affect standing balance and gait stability?MethodsThis study utilized an intervention and cross-over design. Twenty healthy young adults (10 males and 10 females) participated in this study. Standing balance and gait stability were measured using a single force platform and three-dimensional motion analysis system, respectively. The experimental conditions included the control shoe and five RS shoes in the combination of apex position (%) and apex angle (degree) for RS50-95, RS60-95, RS70-95, RS60-70, and RS60-110. The main outcome measures were the area surrounding the maximal rectangular amplitude, mean path length, average displacement of the center of pressure along the lateral and anterior/posterior directions, and maximal center of pressure excursion as the standing balance and lateral margin of stability as the gait stability. Statistical analyses were conducted using a two-way split-plot analysis of variance with repeated measures (with RS design as the within-subject factor and sex as the between-subject factor) and the Bonferroni post hoc test (α = .05).ResultsRegarding the mean path length, RS60-70 was significantly longer than the control shoe, and it showed a significantly increased lateral margin of stability. Thus, RS60-70 was shown to affect standing balance, limit of stability, and gait stability of the frontal plane during gait.SignificanceThese results suggest that the apex angle of the RS design feature affects standing balance and gait stability, and RS60-70 is detrimental to stability. Therefore, when RS with a small apex angle is prescribed, it is necessary to consider the patient’s balance ability.  相似文献   
5.
《The spine journal》2022,22(4):660-676
BACKGROUND CONTEXTPrevious studies have proposed that there is a relationship between low back pain (LBP) and morphology and composition of paraspinal muscles. However, results have been conflicting, especially regarding fatty infiltration of muscles.PURPOSEThe primary goal of this study was to review and analyze results from imaging studies which investigated morphological and composition changes in the multifidus, erector spinae and psoas major muscles in people with LBP.STUDY DESIGN/SETTINGSystematic review with meta-analysis.PATIENT SAMPLEA patient sample was not requiredOUTCOME MEASURESThis review did not have outcome measures.METHODSPubMed, Scopus, Web of Sciences, EMBASE and ProQuest were searched for eligible studies up to 31st July 2020 (all languages). A systematic search of electronic databases was conducted to identify studies investigating the association between the morphology and fat content of lumbar muscles in people with LBP compared with a (no LBP) control group. 13,795 articles were identified. Based on the screening for inclusion/ exclusion, 25 were included. The quality of the studies was evaluated using the Newcastle-Ottawa Scale. From the 25 articles, 20 were included in the meta-analysis.RESULTSResults showed that the total cross-sectional area of the multifidus was smaller in people with LBP (Standardized mean difference, SMD = -0.24, 95% CI = -0.5 to 0.03). Combined SMDs showed a medium effect of LBP on increasing multifidus muscle fat infiltration (SMD = 0.61, 95% CI = 0.30 to 0.91). There were no LBP related differences identified in the morphology or composition of the lumbar erector spine and psoas major muscles.CONCLUSIONSPeople with LBP were found to have somewhat smaller multifidus muscles with a significant amount of intramuscular fat infiltration. Varying sample size, age and BMI of participants, quality of studies and the procedures used to measure fat infiltration are possible reasons for inconsistencies in results of previous studies.  相似文献   
6.
ObjectivesNeurological deterioration (ND) during hospitalization is an independent predictor of poor prognosis after stroke. Risk factors affecting early ND within 48 h post stroke have been intensively investigated, while few data are available on those for late ND after transfer to a wheelchair. Therefore, it was investigated whether hemodynamic factors may affect the late ND during hospitalization.Materials and methodsA retrospective study was conducted on 135 patients with atherothrombotic or cardiogenic cerebral infarction who were admitted to our hospital between April 1st, 2014 and July 31st, 2017. During hospitalization, average, maximum, and minimum values were determined for systolic blood pressure (sBP), diastolic BP (dBP), and heart rate (HR), respectively.135 patients were classified into two groups; ND (+) group, in which modified Barthel index score at the time of transfer to a wheelchair showed five points or more decrease between wheelchair transfer and discharge, and ND (?) group, which did not. Vital indices were compared between the two groups and subjected to ROC-curve analysis.ResultsThe ND (+) group included 32 patients, and the ND (?) 103. Significant differences were found between the groups in four items; sBPmin (p = 0.029), dBPmin (p = 0.019), HRave (p = 0.028), and HRmax (p < 0.01). The ND (+) group showed lower sBPmin and dBPmin, and higher HRave and HRmax than the ND (?) group.ConclusionsLate ND after transfer to a wheelchair is related to the vital indices during hospitalization and should be cautiously managed to prevent late ND  相似文献   
7.
8.
《Journal of endodontics》2020,46(10):1455-1464
IntroductionThe aim of this study was to investigate whether mineral trioxide aggregate (MTA) can be modified with caffeic acid (CA) to form caffeic acid/mineral trioxide aggregate (CAMTA) cement and to evaluate its physicochemical and biological properties as well as its capability in immune suppression and angiogenesis.MethodsMTA was immersed in trishydroxymethyl aminomethane buffer with CA to allow coating onto MTA powders. X-ray diffractometry and tensile stress-strain tests were conducted to assess for physical characteristics of CAMTA and to evaluate for successful modification of MTA. Then, the CAMTA cement was immersed in simulated body fluid to evaluate its hydroxyapatite formation capabilities and Si release profiles. In addition, RAW 264.7 cells and human dental pulp stem cells were used to evaluate CAMTA’s immunosuppressive capabilities and cell responses, respectively. hDPSCs were also used to assess CAMTA’s angiogenic capabilities.ResultsThe X-ray diffractometry results showed that CA can be successfully coated onto MTA without disrupting or losing MTA’s original structural properties, thus allowing us to retain the initial advantages of MTA. CAMTA was shown to have higher mechanical properties compared with MTA and had rougher pitted surfaces, which were hypothesized to lead to enhanced adhesion, proliferation, and secretion of angiogenic- and odontogenic-related proteins. In addition, it was found that CAMTA was able to enhance hydroxyapatite formation and immunosuppressive capabilities compared with MTA.ConclusionsCAMTA cements were found to have improved physicochemical and biological characteristics compared with their counterpart. In addition, CAMTA cements had enhanced odontogenic, angiogenic, and immunosuppressive properties compared with MTA. All of the results of this study proved that CAMTA cements could be a biomaterial for future clinical applications and tissue engineering use.  相似文献   
9.
《Injury》2022,53(12):3962-3969
IntroductionEducators are exposed to several work-related hazards. Evidence suggests musculoskeletal pain, psychological distress, and student-inflicted violence-related injuries are common. However, there is little evidence on the burden of workplace injury among Australian educators.AimTo compare incidence of injury claims and duration of compensated time off work between educators and non-educators, and associated factors.MethodsRetrospective cohort study of 1,559,676 Australian workers’ compensation claims, including 84,915 educator claims, lodged between July 2009 to June 2015, from the National Dataset for Compensation-based Statistics. Cases were included if aged 18+ years and working in the education sector less than 100 h per week. Negative binomial regression models estimated the relative risk of making a compensation claim and survival analyses calculated disability duration within educators by sex, age, injury type and mechanism, socioeconomic area, remoteness, and jurisdiction.ResultsCompared to non-educators, educators had lower rates of injury claims and shorter disability durations. However, educators had a higher rate of claims for mental health conditions and assault, with the highest risk being among those in special education and education aides. Among educators, injury claim rates were highest among special educators, education aides, and secondary educators.Discussion and ConclusionThough surveys indicate Australians in the education sector have higher incidences of work-related injuries, this study found lower incidence of injury claims and shorter disability durations than others. Educators’ injury-reporting and absenteeism behaviors may be constrained by ethical, social, and administrative attitudes. Educators had higher rates of claims for mental health and assault-related injury, particularly special educators, and education aides, which suggests a need for targeted prevention efforts.  相似文献   
10.
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