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   4272篇
  免费   355篇
  国内免费   19篇
耳鼻咽喉   22篇
儿科学   227篇
妇产科学   72篇
基础医学   477篇
口腔科学   134篇
临床医学   517篇
内科学   858篇
皮肤病学   71篇
神经病学   248篇
特种医学   367篇
外科学   646篇
综合类   90篇
预防医学   380篇
眼科学   49篇
药学   260篇
  1篇
中国医学   2篇
肿瘤学   225篇
  2022年   21篇
  2021年   60篇
  2020年   35篇
  2019年   52篇
  2018年   67篇
  2017年   46篇
  2016年   37篇
  2015年   72篇
  2014年   73篇
  2013年   129篇
  2012年   154篇
  2011年   157篇
  2010年   153篇
  2009年   114篇
  2008年   183篇
  2007年   193篇
  2006年   184篇
  2005年   170篇
  2004年   187篇
  2003年   184篇
  2002年   159篇
  2001年   162篇
  2000年   139篇
  1999年   110篇
  1998年   117篇
  1997年   110篇
  1996年   90篇
  1995年   78篇
  1994年   64篇
  1993年   65篇
  1992年   79篇
  1991年   84篇
  1990年   78篇
  1989年   108篇
  1988年   89篇
  1987年   86篇
  1986年   74篇
  1985年   72篇
  1984年   56篇
  1983年   51篇
  1982年   46篇
  1981年   37篇
  1980年   31篇
  1979年   51篇
  1978年   50篇
  1977年   31篇
  1976年   27篇
  1975年   31篇
  1974年   36篇
  1973年   28篇
排序方式: 共有4646条查询结果,搜索用时 0 毫秒
91.

Background

Broad autism phenotype (BAP) is a milder expression of the social and communication impairments seen in autism spectrum disorders (ASD). While prior studies characterized the BAP in unaffected family members of probands with ASD, the relationship between parental BAP traits and proband symptomatology remains poorly understood. This study utilizes the Broad Autism Phenotype Questionnaire (BAPQ) in parents and the Social Responsiveness Scale (SRS) in children to examine this connection. We hypothesized that in families affected by ASD, elevated maternal and paternal BAPQ scores would correlate with greater autism symptomatology in diagnosed children. In an extension of prior research, we also explored this relationship in families with typically developing children (TDC).

Methods

Two hundred and forty-five children with ASD, 129 TDC and all parents were recruited as part of a larger study investigating relationships between genes, brain and behavior. The Autism Diagnostic Interview-Revised (ADI-R), Autism Diagnostic Observation Schedule (ADOS) and expert clinical judgment confirmed ASD diagnoses in children. SRS was collected for all children. Parents completed a self-report BAPQ and an informant report BAPQ for their spouse; an average of self-report and informant report for each parent was used in all analyses.

Results

Mothers and fathers of children with ASD had significantly higher rates of BAP traits as compared to parents of TDC. Maternal and paternal BAPQ total scores were not correlated with child IQ in either group. In the ASD group, 10% of mothers and 21% of fathers scored above the established BAP threshold compared to 4% of TDC parents. Crude regression analyses showed that maternal and paternal BAPQ total scores accounted for significant variance in child SRS scores in both ASD (17.1%) and TDC (19.8%) families.

Conclusions

Our results suggest that broad autism symptomatology in parents is moderately associated with their child’s autism symptomatology. This result extended to TDC families, suggesting that the BAPQ and SRS capture subtle, subclinical social variation in both children and adults. These findings could help define multi-generational social impairments in future phenotypic and genetic studies.  相似文献   
92.

Introduction

Single incision laparoscopic surgery (SILS) is established in many procedures but not in bariatric surgery. One explanation may be that SILS is technically demanding in morbidly obese patients. This report describes our technique and experience with single incision laparoscopic adjustable gastric banding (SILAGB).

Methods

Prospective data collection was performed on consecutive obese patients who underwent SILAGB between November 2009 and February 2011. A single 3cm transverse incision in the right upper quadrant was used for a Covidien SILS multichannel access port. The technique is described with a standard pars flaccida approach and the ‘tips and tricks’ needed for a wide range of candidates using standard laparoscopic equipment.

Results

A total of 29 patients (27 female) with a median body mass index of 41kg/m2 (range: 35–52kg/m2) and median age of 44 years (range: 22–57 years) underwent SILAGB. There were no ‘conversions’ to a standard laparoscopic technique. Two cases required the addition of one single 5mm port. The only complications were two postoperative wound infections (one with a port site infection requiring replacement of the port) and one faulty band requiring replacement. There were therefore two returns to theatre and no 30-day deaths. All patients were discharged on the first postoperative day. In this series, operative times reduced significantly to be comparable with the conventional laparoscopic approach.

Conclusions

SILAGB is safe and feasible in the morbidly obese. Proficiency in this technique using conventional laparoscopic equipment can be achieved with a short learning curve.  相似文献   
93.

Introduction

Distant metastases to liver and lung are not uncommon in colorectal cancer. Resection of metastases is accepted widely as the standard of care. However, there is no firm evidence base for this. This questionnaire survey was carried out to assess the current practice preferences of cardiothoracic surgeons in Great Britain and Ireland.

Methods

An online questionnaire survey was emailed to cardiothoracic surgeons in Great Britain and Ireland. The survey was live for 12 weeks. Responses were collated with SurveyMonkey®.

Results

Overall, there were 75 respondents. The majority (83%) indicated thoracic surgery as a specialist interest. Almost all (99%) used thoracic computed tomography (CT) for staging; 70% added liver CT and 51% added pelvic CT. Fluorodeoxyglucose positron emission tomography was used by 86%. The most frequent indication for pulmonary resection (97%) was solitary lung metastasis without extrathoracic disease. Video assisted thoracoscopic surgery (VATS) was used by 85%. In addition, thoracotomy was used by 96%. A third (33%) used radiofrequency ablation. Synchronous liver and lung resection was contraindicated for 83% of respondents. Over three-quarters (77%) thought that scientific equipoise exists presently for lung resection for colorectal lung metastases but only 21% supported a moratorium on this type of surgery until further evidence becomes available.

Conclusions

The results confirm that the majority of respondents use conventional cross-sectional imaging and either VATS or formal thoracotomy for resection. The results emphasise the continuing need for formal randomised trials to provide evidence of any survival benefit from pulmonary metastasectomy for colorectal lung metastases.  相似文献   
94.
95.

Background

Recreational mountain biking continues to increase in popularity and is a significant source of traumatic injury, including injuries to the hand and wrist.

Methods

A prospective survey of all hand and wrist injuries sustained while participating in recreational mountain biking presenting to the emergency department at the Municipality of Whistler and the District of Squamish was conducted over a 12-month consecutive period.

Results

An analysis of 765 unique emergency department visits with 1,079 distinct injuries was performed. Of these injuries, 511 were sustained to the upper limb. Injury to the metacarpal and metacarpal phalangeal joints was the most common hand injury (52) followed by proximal phalanx and proximal interphalangeal joint (20).

Conclusions

Mountain biking is a frequent source of a variety of upper limb trauma, and preventative efforts are necessary to minimize the burden of these injuries.  相似文献   
96.
STUDY OBJECTIVES: Determine the comorbidity of insomnia with medical problems. DESIGN: Cross-sectional and retrospective. PARTICIPANTS: Community-based population of 772 men and women, aged 20 to 98 years old. MEASUREMENTS: Self-report measures of sleep, health, depression, and anxiety. RESULTS: People with chronic insomnia reported more of the following than did people without insomnia: heart disease (21.9% vs 9.5%), high blood pressure (43.1% vs 18.7%), neurologic disease (7.3% vs 1.2%), breathing problems (24.8% vs 5.7%), urinary problems (19.7% vs 9.5%), chronic pain (50.4% vs 18.2%), and gastrointestinal problems (33.6% vs 9.2%). Conversely, people with the following medical problems reported more chronic insomnia than did those without those medical problems: heart disease (44.1% vs 22.8%), cancer (41.4% vs 24.6%), high blood pressure (44.0% vs 19.3%), neurologic disease (66.7% vs 24.3%), breathing problems (59.6% vs 21.4%), urinary problems (41.5% vs 23.3%), chronic pain (48.6% vs 17.2%), and gastrointestinal problems (55.4% vs 20.0%). When all medical problems were considered together, only patients with high blood pressure, breathing problems, urinary problems, chronic pain, and gastrointestinal problems continued to have statistically higher levels of insomnia than those without these medical disorders. CONCLUSION: This study demonstrates significant overlap between insomnia and multiple medical problems. Some research has shown it is possible to treat insomnia that is comorbid with select psychiatric (depression) and medical (eg, pain and cancer) disorders, which in turn increases the quality of life and functioning of these patients. The efficacy of treating insomnia in many of the above comorbid disorders has not been tested, indicating a need for future treatment research.  相似文献   
97.
AIMS: Establishing and maintaining human tumours in primary culture can be challenging. In this application, a short-term primary culture process is desired to ensure cells maintained in culture are representative of the in vivo tumour for the purpose of chemoresponse testing. To ensure the appropriate cells are being grown, the cultures must be evaluated for malignancy. The clinical gold standard determination of malignancy is cytological evaluation by a cytopathologist. METHODS: Fifty human tumour specimens (breast, colon, lung, ovary) were established and maintained in primary culture. Cytospins were prepared upon initiation of culture and again at completion of the culture process. Cytospins were stained (Diff-Quik, Papanicolaou) and evaluated by a cytopathologist for the percentage of malignant cells at both times. RESULTS: An increase in the percentage of malignant cells was noted in 86% (43/50) of the cultures evaluated; 8% (4/50) of the cultures maintained the same percentage of malignant cells throughout the culture period, and 6% (3/50) displayed a decrease in malignant cells. On average, the percentage of malignant cells increased by 37% and was not associated with the length of culture (range 5-28 days). CONCLUSIONS: The described primary culture process enriches for malignant cells, which is desirable for further evaluation such as chemoresponse testing.  相似文献   
98.
99.

Purpose

Biometals such as zinc and copper have been shown to affect tight junction expression and subsequently blood-brain barrier (BBB) integrity. Whether these biometals also influence the expression and function of BBB transporters such as P-glycoprotein (P-gp) however is currently unknown.

Methods

Using the immortalised human cerebral microvascular endothelial (hCMEC/D3) cell line, an in-cell western assay (alongside western blotting) assessed relative P-gp expression after treatment with the metal ionophore clioquinol and biometals zinc and copper. The fluorescent P-gp substrate rhodamine-123 was employed to observe functional modulation, and inductively coupled plasma mass spectrometry (ICP-MS) provided information on biometal trafficking.

Results

A 24-h treatment with clioquinol, zinc and copper (0.5, 0.5 and 0.1 μM) induced a significant upregulation of P-gp (1.7-fold) assessed by in-cell western and this was confirmed with western blotting (1.8-fold increase). This same treatment resulted in a 23% decrease in rhodamine-123 accumulation over a 1 h incubation. ICP-MS demonstrated that while t8his combination treatment had no effect on intracellular zinc concentrations, the treatment significantly enhanced bioavailable copper (4.6-fold).

Conclusions

Enhanced delivery of copper to human brain microvascular endothelial cells is associated with enhanced expression and function of the important efflux pump P-gp, which may provide therapeutic opportunities for P-gp modulation.
  相似文献   
100.
Purpose

The purpose was to determine whether Appalachian residence alone or in combination with violence was linked to poorer quality of life (QOL).

Methods

Women recently diagnosed and included in either the Kentucky or North Carolina Cancer Registries were interviewed by phone between 2009 and 2015 (n?=?3320; mean age?=?56.74). Response rates were similar by state (40.1 in Kentucky and 40.9% in North Carolina). Appalachian (N?=?990) versus non-Appalachian residents (N?=?2330) were hypothesized to have poorer QOL defined as (a) lower Functional Assessment of Cancer Therapy—General (FACT-G) scores and (b) more symptoms of depression, stress, or comorbid physical conditions. Lifetime intimate partner or sexual violence was first investigated as a moderator then mediator of regional differences. Multiple analyses of covariance (MANCOVA) models were used.

Results

Violence modified the effect of Appalachian residence on poorer QOL outcomes; FACT-G total scores (p?=?.02) were lowest for women living in Appalachia who had additionally experienced violence. Socioeconomic indicators appeared to mediate or explain differences in QOL outcomes by Appalachian residence such that when adjusting for income, education and insurance, Appalachian residence remained associated only with poorer physical QOL outcomes (p?<?.05).

Conclusions

While violence rates did not differ by residence, the combined effect of living in Appalachia and experiencing violence resulted in significantly greater impact on poorer QOL among women recently diagnosed with cancer. Clinical consideration of patients’ residence, socioeconomic status and violence experienced may help identify and mitigate the longer-term impact of these identifiable factors associated with poorer QOL.

  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