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   936篇
  免费   52篇
  国内免费   20篇
耳鼻咽喉   3篇
儿科学   31篇
妇产科学   10篇
基础医学   67篇
口腔科学   26篇
临床医学   166篇
内科学   170篇
皮肤病学   2篇
神经病学   130篇
特种医学   174篇
外科学   52篇
综合类   28篇
预防医学   38篇
眼科学   29篇
药学   49篇
肿瘤学   33篇
  2023年   6篇
  2022年   5篇
  2021年   12篇
  2019年   3篇
  2018年   8篇
  2017年   6篇
  2016年   11篇
  2015年   5篇
  2014年   16篇
  2013年   32篇
  2012年   33篇
  2011年   30篇
  2010年   29篇
  2009年   52篇
  2008年   26篇
  2007年   36篇
  2006年   30篇
  2005年   30篇
  2004年   18篇
  2003年   24篇
  2002年   22篇
  2001年   27篇
  2000年   30篇
  1999年   19篇
  1998年   41篇
  1997年   41篇
  1996年   40篇
  1995年   39篇
  1994年   23篇
  1993年   25篇
  1992年   14篇
  1991年   17篇
  1990年   15篇
  1989年   31篇
  1988年   27篇
  1987年   17篇
  1986年   9篇
  1985年   17篇
  1984年   12篇
  1983年   11篇
  1982年   19篇
  1981年   12篇
  1980年   17篇
  1978年   11篇
  1977年   14篇
  1976年   9篇
  1975年   3篇
  1974年   5篇
  1973年   7篇
  1971年   7篇
排序方式: 共有1008条查询结果,搜索用时 15 毫秒
991.
ABSTRACT: BACKGROUND: There is an urgent need to develop and evaluate weight management interventions to address childhood obesity. Recent research suggests that interventions designed for parents exclusively, which have been named parents as agents of change (PAC) approaches, have yielded positive outcomes for managing pediatric obesity. To date, no research has combined a PAC intervention approach with cognitive behavioural therapy (CBT) to examine whether these combined elements enhance intervention effectiveness. This paper describes the protocol our team is using to examine two PAC-based interventions for pediatric weight management. We hypothesize that children with obesity whose parents complete a CBT-based PAC intervention will achieve greater reductions in adiposity and improvements in cardiometabolic risk factors, lifestyle behaviours, and psychosocial outcomes than children whose parents complete a psycho-education-based PAC intervention (PEP). METHODS: This study is a pragmatic, two-armed, parallel, single-blinded, superiority, randomized clinical trial. The primary objective is to examine the differential effects of a CBT-based PAC vs PEP-based PAC intervention on children's BMI z-score (primary outcome). Secondary objectives are to assess intervention-mediated changes in cardiometabolic, lifestyle, and psychosocial variables in children and parents. Both interventions are similar in frequency of contact, session duration, group facilitation, lifestyle behaviour goals, and educational content. However, the interventions differ insofar as the CBT-based intervention incorporates theory-based concepts to help parents link their thoughts, feelings, and behaviours; these cognitive activities are enabled by group leaders who possess formal training in CBT. Mothers and fathers of children (8-12 years of age; BMI greater than or equal to the 85th percentile) are eligible to participate if they are proficient in English (written and spoken) and agree for at least one parent to attend group-based sessions on a weekly basis. Anthropometry, cardiometabolic risk factors, lifestyle behaviours, and psychosocial health of children and parents are assessed at pre-intervention, post-intervention, 6-, and 12-months follow-up. DISCUSSION: This study is designed to extend findings from earlier efficacy studies and provide data on the effect of a CBT-based PAC intervention for managing pediatric obesity in a real-world, outpatient clinical setting.  相似文献   
992.

Objective

The purpose of this case study is to describe the clinical presentation of a patient with a chief complaint of low back and leg pain with no prior diagnosis of lung cancer.

Clinical Features

A 48-year-old man with a history of back pain presented to a chiropractic office with a complaint of low back and left leg pain.

Intervention and Outcome

Abnormal examination and radiographic findings were discovered. The patient was immediately referred to the pulmonologist for co-management. Through the use of advanced imaging and biopsy, stage 4 lung cancer was diagnosed.

Conclusion

Low back pain recurrence in an established patient should constitute a reevaluation of the problem. The cause cannot be assumed to be musculoskeletal in origin even though this may have been the case with the initial complaint. Metastatic disease should be considered with any type of recurrent low back pain.  相似文献   
993.

Objective

The purpose of this study was to determine whether healthy adult volunteers report symptoms following exposure to low-speed frontal crashes at low velocities.

Methods

Nineteen medically screened, healthy, informed, and willing volunteers (17 men, 2 women; mean age, 37 years) were exposed to low-speed frontal crashes. All volunteers were seated in the rear seat position of the bullet vehicle. Closing velocities ranged from 4.1 to 8.3 mph (mean, 6.7 mph). For the bullet vehicle, the delta V ranged from 1.4 to 3.9 mph with a mean of 2.8 mph.

Results

Eighty-eight percent of volunteers attributed symptoms of discomfort to their crash exposure. All reported symptoms were transient, and none required medical treatment. The mean duration was 1 day.

Conclusions

Even at relatively low speeds, there is no lower threshold below which it can be reasonably assumed that healthy and prepared volunteer rear seat passengers will not sustain some level of minor injury in a frontal collision. Although the reported mean delta V for injured persons in real-world frontal crashes has been reported to be as high as 8.1 mph, this does not offer any insight into the minimum threshold for such injuries among all at-risk vehicle occupants.  相似文献   
994.
It is well recognized that preterm birth is the leading cause of perinatal mortality and morbidity. There is a significant association between cervix length and preterm birth risk. Most authorities consider a cervical length <3 cm as the lower limit of normal. A cervical length >3 cm has a high negative predictive value for delivery less than 34 weeks. A cervical length of <15 mm is moderately predictive (~ 70%) of preterm birth within 48 hours. Cervical length is normally distributed and should remain relatively constant until the third trimester. Transabdominal US is the least reliable method of cervical length assessment. The most reliable method of documenting cervical length is transvaginal ultrasound (TVUS). Transperineal US is an alternative for imaging if TVUS is contraindicated, such as with premature rupture of membranes. However, the resolution is decreased compared to TVUS. Short cervix length is the single most important predictive finding for premature delivery. This observation should prompt consultation for high risk obstetrical care and consideration of other management options such as cerclage or activity restriction.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed biennially by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging.  相似文献   
995.

Background:

Lateral closed wedge (LCW) osteotomy is a commonly accepted method for the correction of the cubitus varus deformity. The fixation of osteotomy is required to prevent loss of correction achieved. The fixation of the osteotomy by the two screw and figure of eight wire is not stable enough to maintain the correction achieved during surgery. In this prospective study we supplemented the fixation by Kirschner''s (K-) wires for stable fixation and evaluated the results.

Materials and Methods:

Twenty-one cases of the cubitus varus deformity following supracondylar fractures of the humerus were operated by LCW osteotomy during February 2001 to June 2006. The mean age of the patients at the time of corrective surgery was 8.5 years (range 6.6-14 years). The osteotomy was fixed by two screws with figure of eight tension band wire between them and the fixation was supplemented by passing two to three K-wires from the lateral condyle engaging the proximal medial cortex through the osteotomy site.

Result:

The mean follow-up period was 2.5 years (range seven months to 3.4 years). The results were assessed as per Morrey criteria. Eighteen cases showed excellent results and three cases showed good results. Two cases had superficial pin tract infection.

Conclusion:

The additional fixation by K wires controls rotational forces effectively besides angulation and translation forces and maintains the correction achieved peroperatively.  相似文献   
996.
BACKGROUND: Compounds that reduce N-methyl-d-aspartate receptor (NMDAR) function, including NMDAR antagonists and partial agonists at the NMDAR-associated glycine (GLY) site, may act as antidepressants. The antibiotic drug d-cycloserine (DCS) acts as a partial agonist at the NMDAR-GLY site. Preclinical and clinical data suggest that at dosages >or=100 mg/day DCS acts as a functional NMDAR antagonist and may have antidepressant effects. METHODS: Twenty-two treatment resistant major depression patients participated in a double-blind, placebo-controlled 6-week crossover trial with 250 mg/day DCS added to their ongoing antidepressant medications. RESULTS: DCS treatment was well tolerated and resulted in symptom reductions. However, biweekly-performed clinical assessments, including the Hamilton Depression Rating Scale, Hamilton Rating Scale for Anxiety and Zung Self-Rating Depression Scale did not reveal statistically significant therapeutic advantages of DCS vs. placebo adjuvant treatment. LIMITATIONS: Small sample, uneven treatment resistance criteria across subjects. The exposure to DCS (dose/length of treatment) may not have been sufficient. CONCLUSIONS: This exploratory study represents the first attempt to assess the effects of a NMDAR-GLY site partial agonist in depression treatment. The findings and limitations of this study should be taken into account in the planning of future clinical trials with NMDAR modulators in depression.  相似文献   
997.
998.
This special issue focuses on the theme of sensory processing dysfunction in schizophrenia. For more than 50 years, from approximately the time of Bleuler until the early 1960s, sensory function was considered one of the few preserved functions in schizophrenia (Javitt1). Fortunately, the last several decades have brought a renewed and accelerating interest in this topic. The articles included in the issue range from those addressing fundamental bases of sensory dysfunction (Brenner, Yoon, and Turetsky) to those that examine how elementary deficits in sensory processing affect the sensory experience of individuals with schizophrenia (Butler, Kantrowitz, and Coleman) to the question of how sensory-based treatments may lead to improvement in remediation strategies (Adcock). Although addressing only a small portion of the current complex and burgeoning literature on sensory impairments across modalities, the present articles provide a cross-section of the issues currently under investigation. These studies also underscore the severe challenges that individuals with schizophrenia face when trying to decode the complex world around them.  相似文献   
999.
Parkinson's disease (PD) manifestations include motor symptoms and behavioural deficits that resemble schizophrenia negative symptoms. The N-methyl-D-aspartate subtype of glutamate receptor (NMDAR) represents a novel pharmacological target in PD. D-serine (DSR) allosterically modulates in-vivo NMDAR-mediated neurotransmission and has been shown to improve negative and antipsychotic drug-induced parkinsonian symptoms in schizophrenia patients. This pilot study assessed DSR effects in ten PD patients who completed a 6-wk double-blind, placebo-controlled, crossover adjuvant treatment trial with 30 mg/kg.d DSR. Primary outcome analyses consisted of separate repeated-measures multivariate analyses of variance for Unified Parkinson's Disease Rating Scale (UPDRS), Simpson-Angus Scale for Extrapyramidal Symptoms (SAS), Abnormal Involuntary Movement Scale (AIMS), and Positive and Negative Syndrome Scale (PANSS) scores. DSR treatment was well tolerated and resulted in increased DSR serum levels (p=0.001) and significantly reduced UPDRS (p=0.02), SAS (p=0.009) and PANSS (0.05) total scores. These preliminary findings suggest that DSR treatment may be beneficial in PD. Larger-sized studies with optimized DSR dosages are warranted.  相似文献   
1000.
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