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   10146篇
  免费   977篇
  国内免费   162篇
耳鼻咽喉   44篇
儿科学   201篇
妇产科学   208篇
基础医学   1198篇
口腔科学   260篇
临床医学   1169篇
内科学   1385篇
皮肤病学   36篇
神经病学   760篇
特种医学   843篇
外国民族医学   1篇
外科学   1127篇
综合类   1170篇
现状与发展   1篇
预防医学   1015篇
眼科学   129篇
药学   919篇
  4篇
中国医学   210篇
肿瘤学   605篇
  2024年   54篇
  2023年   368篇
  2022年   448篇
  2021年   768篇
  2020年   503篇
  2019年   466篇
  2018年   383篇
  2017年   430篇
  2016年   398篇
  2015年   405篇
  2014年   724篇
  2013年   809篇
  2012年   550篇
  2011年   565篇
  2010年   449篇
  2009年   453篇
  2008年   386篇
  2007年   387篇
  2006年   358篇
  2005年   302篇
  2004年   270篇
  2003年   195篇
  2002年   174篇
  2001年   150篇
  2000年   129篇
  1999年   118篇
  1998年   117篇
  1997年   105篇
  1996年   86篇
  1995年   86篇
  1994年   74篇
  1993年   76篇
  1992年   64篇
  1991年   57篇
  1990年   48篇
  1989年   37篇
  1988年   52篇
  1987年   28篇
  1986年   32篇
  1985年   31篇
  1984年   39篇
  1983年   14篇
  1982年   29篇
  1981年   9篇
  1980年   18篇
  1979年   13篇
  1978年   8篇
  1977年   6篇
  1973年   5篇
  1972年   3篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Background There is a high rate of physical violence in populations with intellectual disabilities, and this has been linked to problems for the victim, the assailant, members of staff and services. Despite the clinical significance of this behaviour, few studies have assessed methods of predicting its occurrence. The present study examined clinical and actuarial methods of predicting violence in a forensic intellectual disability hospital. Methods The sample for the study consisted of people resident in the hospital during a 1‐year period (n = 124). Clinical prediction used a risk rating made by members of the person's clinical team, whereas actuarial prediction used the number of violent incidents in the 6‐months before the date of the clinical risk assessment. Computerized hospital records of violence in the 6 months after the assessment were used to examine the predictive accuracy of the two methods. Results The clinical method produced an area under the curve of 0.74 (95% CI: 0.65–0.83) in a receiver–operating characteristic curve analysis. The value for the actuarial method was 0.77 (95% CI: 0.69–0.86). Both methods performed at levels significantly above chance, but no one method was found to be superior to the other. Conclusions These findings suggest that it is possible to predict who is at risk of violence in forensic populations with intellectual disabilities. Here, the authors discuss the clinical implications of these findings and the clinical application of risk prediction within clinical services.  相似文献   
32.
A recently introduced setup to measure the dynamic interfacial tension of expanding drops was used to compare the adsorption behaviour of a series of lipids at the electrified water∣dichloroethane interface. Phospholipids with saturated carbon chains of different length (DMPC, DPPC, DSPC, DAPC, DBPC), an unsaturated phospholipid (DOPC) and an ethanolamine (DSPE) were compared. It was found that the adsorption decreases with increasing chain length. Also, the increase of the flow rate reduces the degree of adsorption effectively. On the timescale of the experiments, the DSPE, DAPC and DBPC adsorption showed no potential dependence, whereas the adsorption of DOPC was stronger than that of the saturated lipids. Adsorption was modelled using the Langmuir adsorption isotherm; the potential dependence of adsorption is discussed.  相似文献   
33.
A suboptimal controller for a class of discrete-time systems is presented. The controller is derived by first solving ‘off-line’ a simplified optimal control problem obtained by neglecting part of the system state and by considering a larger time step, then by solving ‘on-line’ at each time step an optimization problem based on the results of the previously solved ‘off-line’ problem. A simple numerical example is presented to illustrate the control scheme.  相似文献   
34.
AIM: The aim of this study was to explore a birthweight prediction model using ultrasound determined tissue thickness (SCTT) parameters. METHODS: We measured routine ultrasonographic biometric parameters and in addition, fetal SCTT in 201 healthy singleton pregnancies. Mid-arm fat and lean mass, mid-thigh fat and lean mass, subscapular fat mass and abdominal fat mass (AFM) were measured in order to calculate a birthweight prediction model. Ultrasound measurements were analyzed using an 'anovarepeated measures model'. The growth rate (beta-slope) of the selected parameters was computed and the correlation coefficient with the birthweight and the Kendall rank correlation tau, were calculated. RESULTS: From the ultrasound determined SCTT parameters, only abdominal circumference (AC), AFM, and MTLM showed a statistically significant trend. The beta-slope of mid-thigh lean mass was excluded since it exhibited significant correlation with the beta-slope of AFM. The final regression model could be calculated as: birthweight (gr.) = intercept +alpha(1)(AFM beta-slope) + alpha(2)(AC beta-slope), where alpha(1), alpha(2) represent regression coefficients. CONCLUSIONS: We provide a graphical birthweight prediction model for clinical practice using conventional and specific ultrasound measurements of fetal subcutaneous tissue thickness. This model is based upon an overall analysis of the ultrasound estimated body components.  相似文献   
35.
目的:动态监测急性有机磷中毒动物在急性有机磷中毒及解救过程中血浆的乙酰胆碱酯酶活性和血糖值变化,依据此两项指标与中毒程度的相关性,为临床救治提供新的方法以及实验依据。方法:通过耳缘静脉注射5%敌百虫溶液(2mL/kg)先后对12只家兔建立急性有机磷中毒模型,分别在模型动物处于正常、轻、中、重度中毒和救治的时段采血,动态监测血浆乙酰胆碱酯酶活力和血糖两项指标变化。结果:在急性有机磷中毒过程中,血糖值升高与乙酰胆碱酯酶活力降低相比较,血糖浓度动态变化与中毒轻重程度相关性较好,并能体现机体对中毒的应激程度。结论:血糖浓度能较好地反映有机磷中毒深度以及机体应激程度,可作为临床评估危重程度的动态性快速诊断指标。  相似文献   
36.
动力髋螺钉治疗股骨转子间骨折   总被引:6,自引:0,他引:6  
目的 评价动力髋螺钉(DHS)治疗股骨转子间骨折的临床效果。方法 1996年3月~2002年3月用DHS共治疗患者29例.骨折按Evans分型,本组Evans ⅠA2例,Evans ⅠB 10例,Evans ⅡA 3例,Evanslib12例,Evans Ⅲ2例.结果 29例患者均获随访,随访12~48个月,平均26个月,根据Harris髋关节评分:优16例,良9例,中3例,差1例。结论 如能及时手术良好复位,DHS是治疗股骨转子间骨折的较好选择。  相似文献   
37.
BACKGROUND: Clinical trials indicate that electroconvulsive therapy (ECT) is the most effective treatment for major depression, but its effectiveness in community settings has not been examined. METHODS: In a prospective, naturalistic study involving 347 patients at seven hospitals, clinical outcomes immediately after ECT and over a 24-week follow-up period were examined in relation to patient characteristics and treatment variables. RESULTS: The sites differed markedly in patient features and ECT administration but did not differ in clinical outcomes. In contrast to the 70%-90% remission rates expected with ECT, remission rates, depending on criteria, were 30.3%-46.7%. Longer episode duration, comorbid personality disorder, and schizoaffective disorder were associated with poorer outcome. Among remitters, the relapse rate during follow-up was 64.3%. Relapse was more frequent in patients with psychotic depression or comorbid Axis I or Axis II disorders. Only 23.4% of ECT nonremitters had sustained remission during follow-up. CONCLUSIONS: The remission rate with ECT in community settings is substantially less than that in clinical trials. Providers frequently end the ECT course with the view that patients have benefited fully, yet formal assessment shows significant residual symptoms. Patients who do not remit with ECT have a poor prognosis; this underscores the need to achieve maximal improvement with this modality.  相似文献   
38.
One hundred forty five individuals who sought medical attention as a result of a motor vehicle accident (MVA), and who were initially assessed 1 to 4 months post-MVA, were followed up prospectively for 6 months to determine how many of the 55 with posttraumatic stress disorder (PTSD) and the 43 with sub-syndromal PTSD would remit and what variables would predict remission. Thirty (55%) of those with initial PTSD had remitted at least in part by 6 months while 67% of those with sub-syndromal PTSD had remitted (and 5% had worsened). Four variables, including severity of initial symptoms, degree of initial physical injury, relative degree of physical recovery by 4 months and whether a close family member suffered a trauma during the follow-up interval, combined to classify 6-month clinical status of 84% of those with initial PTSD secondary to MVAs.  相似文献   
39.
A population kinetic analysis was carried out on sparse plasma gentamicin (GE) concentration data from 469 neonates obtained as part of a routine therapeutic drug monitoring (TDM) programme in the hospital neonatology unit.The best predictors of the kinetic parameters of the monoexponential model, volume of distribution (Vd) and clearance (CL), were the weight (WT) and gestational age (GA). Vd of the neonates was only related to WT, whereas the half-life was only related to the GA.  相似文献   
40.
视电生理检查在白内障患者视觉功能预测中的意义   总被引:1,自引:0,他引:1  
  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