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   286篇
  免费   10篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   21篇
妇产科学   3篇
基础医学   48篇
口腔科学   2篇
临床医学   31篇
内科学   35篇
神经病学   72篇
特种医学   3篇
外科学   17篇
综合类   2篇
一般理论   1篇
预防医学   14篇
眼科学   5篇
药学   27篇
肿瘤学   15篇
  2023年   4篇
  2022年   3篇
  2021年   9篇
  2020年   14篇
  2019年   7篇
  2018年   8篇
  2017年   8篇
  2016年   8篇
  2015年   10篇
  2014年   11篇
  2013年   10篇
  2012年   26篇
  2011年   24篇
  2010年   15篇
  2009年   18篇
  2008年   28篇
  2007年   22篇
  2006年   18篇
  2005年   15篇
  2004年   11篇
  2003年   10篇
  2002年   8篇
  2001年   1篇
  1998年   1篇
  1996年   3篇
  1995年   3篇
  1993年   1篇
  1978年   1篇
排序方式: 共有297条查询结果,搜索用时 156 毫秒
1.
The genetic and environmental mediation of continuity and change in parent-reported ADHD symptoms were investigated in a cohort of over 6000 twin pairs at 2, 3 and 4 years of age. Genetic analyses of the cross-sectional data yielded heritability estimates of 0.78–0.81 at each age, with contrast effects. A common pathway model provided the best fit to the longitudinal data, indicating that genetic influences underlie 91% of the stable variance in ADHD symptomatology. In other words, what is stable for ADHD symptoms is largely genetic. Contrast effects acting in the same direction at different ages contributed to the observed continuity:longitudinal correlations were greater for dizygotic than monozygotic twins.The Twins Early Development Study is funded by the Medical Research Council.  相似文献   
2.
3.
Aims   To investigate whether substance use disorders (SUDs) are associated with verbal intellectual ability, psychomotor processing speed, verbal and visual working memory, executive function and verbal learning in young adults, and to study the associations of SUD characteristics with cognitive performance.
Participants   A population-based sample ( n  = 466) of young Finnish adults aged 21–35 years.
Measurements   Diagnostic assessment was based on all available information from a structured psychiatric interview (SCID-I) and in- and out-patient medical records. Established neuropsychological tests were used in the cognitive assessment. Confounding factors included in the analyses were comorbid psychiatric disorders and risk factors for SUDs, representing behavioural and affective factors, parental factors, early initiation of substance use and education-related factors.
Findings   Adjusted for age and gender, life-time DSM-IV SUD was associated with poorer verbal intellectual ability, as measured with the Wechsler Adult Intelligence Scale–Revised (WAIS-R) vocabulary subtest, and slower psychomotor processing, as measured with the WAIS-R digit symbol subtest. Poorer verbal intellectual ability was accounted for by parental and own low basic education, whereas the association with slower psychomotor processing remained after adjustment for SUD risk factors. Poorer verbal intellectual ability was related to substance abuse rather than dependence. Other SUD characteristics were not associated with cognition.
Conclusions   Poorer verbal intellectual ability and less efficient psychomotor processing are associated with life-time alcohol and other substance use disorders in young adulthood. Poorer verbal intellectual ability seems to be related to parental and own low basic education, whereas slower psychomotor processing is associated with SUD independently of risk factors.  相似文献   
4.
Doping of the conjugated polymer poly(3-hexylthiophene) (P3HT) with the p-dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) is a widely used model system for organic thermoelectrics. We here study how the crystalline order influences the Seebeck coefficient of P3HT films doped with F4TCNQ from the vapour phase, which leads to a similar number of F4TCNQ anions and hence (bound + mobile) charge carriers of about 2 × 10−4 mol cm−3. We find that the Seebeck coefficient first slightly increases with the degree of order, but then again decreases for the most crystalline P3HT films. We assign this behaviour to the introduction of new states in the bandgap due to planarisation of polymer chains, and an increase in the number of mobile charge carriers, respectively. Overall, the Seebeck coefficient varies between about 40 to 60 μV K−1. In contrast, the electrical conductivity steadily increases with the degree of order, reaching a value of more than 10 S cm−1, which we explain with the pronounced influence of the semi-crystalline nanostructure on the charge-carrier mobility. Overall, the thermoelectric power factor of F4TCNQ vapour-doped P3HT increases by one order of magnitude, and adopts a value of about 3 μW m−1 K−2 in the case of the highest degree of crystalline order.

The crystallinity of P3HT strongly benefits the electrical conductivity but not Seebeck coefficient, leading to an increase in power factor by one order of magnitude.  相似文献   
5.
6.
The US Food and Drug Administration issued a black box warning in 2012 regarding the association of statin use with cognitive impairment. This may deter patients and practitioners from using statins for guideline-directed indications. Large studies have not shown an increase in cognitive impairment with statin use. MEDLINE, EMBASE, and Cochrane databases were searched up to October 2019. We present an up-to-date systematic review of randomized controlled trials (RCTs) and prospective observational studies examining the association between statin use and cognitive status in a population aged ≥60 years. Twenty-four studies with 1,404,459 participants were included in the review. Twenty-one were prospective observational studies, and 3 were RCTs. All 3 RCTs, which ranged from 3.2 to 5.6 years of follow-up, showed no significant association between statin use and adverse cognitive effects (odds ratio [OR] 1.03 [0.82–1.30]) and (OR 1.0 [0.61–1.65]). The mean difference in the Mini-Mental State Examination was insignificant (0.06 [?0.04 to 0.16]) in the third RCT. The follow-up for observational studies ranged from 3 to 15 years. Ten observational studies showed reduced incidence of dementia. Seven showed no association with incident dementia. Three studies showed decline in cognition was similar, whereas one showed slower decline with statin use. There was no evidence of adverse cognitive effects, including incidence of dementia, deterioration in global cognition, or specific cognitive domains associated with statin use in individuals aged ≥60 years. Future studies should examine this association in studies with longer follow-up periods.  相似文献   
7.
8.
Critical appraisal and application of the evidence to practice cannot proceed without first finding the evidence. To teach evidence-based practice database searching skills to students, a nurse educator partnered with a librarian to design, conduct, and assess instruction. The authors describe the creation, administration, and findings from the assessments and the implications for instruction.  相似文献   
9.
10.

Introduction and hypothesis

The aim of the study was to evaluate a new follow-up practice after anterior colporrhaphy for central cystocele involving nurse telephone follow-up.

Methods

A retrospective follow-up of all 84 patients with an anterior colporrhaphy operation during 2011 was performed. Standard postoperative procedure in uncomplicated cases of cystocele operation (first-time cystocele operation, no preoperative incontinence or voiding difficulties, and no immediate postoperative complications) was a telephone interview performed by a continence nurse 3 months after patient surgery. A local checklist comprising questions concerning complications, voiding dysfunction, and sexual life, as well as questions from the International Consultation on Incontinence Vaginal Symptoms (ICIQ-VS) and the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) were used. Complex cases were followed by the surgeon with a consultation including gynecological examination after 3 months.

Results

Out of 84 patients with a cystocele operation, 59 were uncomplicated and had a telephone follow-up. Forty-four (75 %) were satisfied and needed no further consultation in the hospital. One patient could not be contacted. Fourteen patients had a consultation, three before the telephone consultation because of bleeding, five because of anxiety, and one each because of voiding dysfunction and prolapse symptoms. Four patients had persisting urinary incontinence and were incorrectly scheduled for a telephone interview.

Conclusions

Selecting uncomplicated cases for a nurse telephone follow-up after cystocele operation is feasible in a majority of cases. This allows doctors to see more new patients and focus on difficult cases, as well as saving time and money.  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