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   9870篇
  免费   709篇
  国内免费   20篇
耳鼻咽喉   71篇
儿科学   356篇
妇产科学   182篇
基础医学   1428篇
口腔科学   187篇
临床医学   1568篇
内科学   1821篇
皮肤病学   139篇
神经病学   994篇
特种医学   151篇
外科学   832篇
综合类   97篇
一般理论   19篇
预防医学   1342篇
眼科学   105篇
药学   683篇
中国医学   35篇
肿瘤学   589篇
  2023年   71篇
  2022年   102篇
  2021年   208篇
  2020年   148篇
  2019年   205篇
  2018年   263篇
  2017年   197篇
  2016年   198篇
  2015年   229篇
  2014年   337篇
  2013年   509篇
  2012年   653篇
  2011年   801篇
  2010年   460篇
  2009年   365篇
  2008年   720篇
  2007年   704篇
  2006年   704篇
  2005年   669篇
  2004年   621篇
  2003年   524篇
  2002年   530篇
  2001年   84篇
  2000年   58篇
  1999年   97篇
  1998年   131篇
  1997年   82篇
  1996年   81篇
  1995年   66篇
  1994年   67篇
  1993年   64篇
  1992年   59篇
  1991年   45篇
  1990年   41篇
  1989年   45篇
  1988年   28篇
  1987年   29篇
  1986年   19篇
  1985年   25篇
  1984年   23篇
  1983年   29篇
  1982年   40篇
  1981年   44篇
  1980年   34篇
  1979年   27篇
  1978年   36篇
  1977年   18篇
  1975年   16篇
  1973年   12篇
  1972年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
953.
954.
Other people’s eye-gaze is a powerful social stimulus that captures and directs visual attention. There is evidence that this is not the case for children with autism spectrum disorder (ASD), although less is known about attention to eye-gaze in adults. We investigated whether young adults would detect a change to the direction of eye-gaze in another’s face more efficiently than a control change (presence/absence of spectacles). A change blindness method was used in which images showed faces as part of a complex, naturalistic scene. Results showed that adults with ASD, like typically developing controls, were faster and more accurate at detecting eye-gaze than control changes. Results are considered in terms of a developmental account of the relationship between social attention and other skills.
Sue Fletcher-WatsonEmail:
  相似文献   
955.
The Pre-Elementary Education Longitudinal Study (PEELS) examines the preschool and early elementary school experiences of a nationally representative sample of 3,104 children ages 3-5 with disabilities from 2004 through 2009. This paper describes the special education and related services received by a subsample of 186 preschoolers with autism spectrum disorders (ASD) in 2003-2004 and parental satisfaction with those services. Past research and patterns of litigation suggest that parents of children with ASD are not wholly satisfied with the special education and related services their children receive. In the current study, the authors found many similarities between children with ASD and children with other disabilities in the type of services received under IDEA and in parent satisfaction with these services. Still, some significant differences emerged in the number of services received, the amount of time children with ASD spent in special education settings, and parent satisfaction with the amount of time children spent with typically developing peers. Implications about the importance of parent satisfaction and social validity measures are discussed.  相似文献   
956.
We describe an in utero model in which it is possible to investigate the involvement of supraspinal and spinal neurons in the genesis of spontaneous motor activity, a feature of early fetal life. To date almost all studies of the circuits that give rise to spontaneous motor activity during early ontogeny, and the neurotransmitters involved, have been carried out with in vitro models. Limitations of in vitro models include the relatively short viability of the preparation and the need to stimulate the nervous system either pharmacologically or electrically to produce the activity to be studied, in contrast to the activity that spontaneously occurs normally in utero. Our model uses fetal sheep, chronically instrumented with electromyogram electrodes and a catheter placed either intrathecally at the spinal level or in the peritoneal cavity. Motor activity can be studied over lengthy periods of fetal life and it is possible to examine the effects of infusing agonists and antagonists of central neurotransmitters on spontaneous motor activity. The use of our new model in parallel with the pre-existing in vitro models has the potential to add substantially to our understanding of the mechanisms behind changes in spontaneous activity that occur throughout fetal life.  相似文献   
957.
Background The objective of the present study was to investigate vitamin A nutritional status in individuals with class III obesity through a biochemical indicator (retinol and β-carotene serum levels), correlating these findings with non-alcoholic fatty liver disease (NAFLD) presence and its risk factors. Methods The studied population was composed of 145 patients with morbid obesity [body mass index, BMI ≥ 40 kg/m2) of both sexes. Retinol and β-carotene serum levels were assessed by high performance liquid chromatography. The cutoff values used for serum retinol and β-carotene inadequacy were <1.05 μmol/l and ≤40 μg/dl, respectively. Insulin resistance (IR) was assessed through homeostasis model assessment index (HOMA) method. Biochemical parameters of liver enzymes, lipid profile, and glycemia were analyzed. Anthropometric measurements were conducted. NAFLD diagnosis was performed through magnetic resonance. Results NAFLD prevalence in the group was 71%. An inadequacy of 11.3 and 41.7% of retinol and β-carotene serum levels, respectively, was found when NAFLD was present. A significant correlation of serum retinol with albumin liver and total bilirubin was found. As regards β-carotene, a positive correlation for HDL-c variable and a negative correlation for the HOMA-IR, weight, and BMI variables were observed. There was a significant association between IR presence and retinol and β-carotene inadequacy. Conclusion The high inadequacy of retinol and β-carotene nutritional status in the sample, with a higher inadequacy in those with NAFLD, suggests an increase in the utilization of vitamin A in this group related to the fight against the oxidative stress to what they are exposed to. The significant association between retinol and β-carotene with IR supports the hypothesis that vitamin A may have a protector effect on IR pathogenesis. Financial support: FAPERJ and CNPq.  相似文献   
958.
This study was undertaken to examine the impact of chronic leg ulceration on patients' health-related quality of life in an audit of practice in Lisbon, Portugal, and to observe the changes following 12 weeks of treatment. A questionnaire was administered at entry into an observational study and following 12 weeks of treatment. Patients entering the study were asked to complete the Nottingham Health Profile (NHP), Euroqol and visual analogue (VA) pain questionnaires at entry and after 12 weeks. Principal analysis compared final scores with those found at baseline and compared results with Portuguese normative data. In total, 98 patients entered the study and completed the initial questionnaire, with 68 (69.3%) patients completing the follow-up questionnaire. There were significantly (P < 0.001) higher scores for the patients compared with normative data for all domains of the NHP (all P < 0.001). Improvements were noted for all NHP scores after 12 weeks, although only bodily pain showed a significant improvement [mean difference (d) = 10.5, P = 0.003], with significant improvement also in Euroqol (d = 0.10, P = 0.027). Energy and social isolation improved substantially in the eight (11.8%) patients whose ulcers healed, but did not achieve statistical significance, although VA pain score did (d = 4.85, P < 0.001). Patients suffering from leg ulceration show modest improvements in perceived health following 12 weeks of usual care in Portugal. Improvements in practice may enhance the magnitude of these improvements.  相似文献   
959.
The purpose of this study was to determine if reduction in spike frequency in children with benign epilepsy of childhood with centrotemporal spikes treated with sulthiame correlates with improved neuropsychologic function. Six untreated children (5 boys, 1 girl) with a mean (standard deviation) age of 9.1 years (1.5 years) underwent overnight ambulatory electroencephalograph recording and neuropsychologic evaluation at baseline and after 6 months of sulthiame monotherapy. The Reliable Change Index was used to determine whether a statistically reliable change in neuropsychologic function occurred. All children continued receiving sulthiame monotherapy (dose range, 8.0-9.3 mg/kg per day) for the study period without further seizures. Although spike frequency was reduced in all 6 children (3 showing a decrease to less than 10% of baseline), they all demonstrated significant deterioration in their reading ability, 5 had significant declines in general memory, and more than half had reduction in attention skills and mathematics ability. Although sulthiame was effective at seizure control and significantly reduced spike frequency in children, it was also associated with deterioration in cognitive function.  相似文献   
960.
Unexplained mental retardation is noted in up to 3% of the general population, and upwards of 30% of these patients manifest epilepsy. There is no standardized approach to metabolic testing in these patients. In a first step toward a standardized approach for our center, we performed a retrospective evaluation of testing of our patients in the past. Records of 429 children admitted to our pediatric epilepsy-monitoring center in 2005 were reviewed. We noted whether they had developmental delay, their type of epilepsy, and the extent of metabolic testing. Ninety percent of our patients had developmental delay, and 20% received some form of metabolic testing. Abnormal results suggesting mitochondrial dysfunction were found in 28% of our patients without a previous underlying diagnosis. Metabolic abnormalities were found in 75% of those with multifocal interictal discharges. Secondary carnitine deficiency was identified in 22%; these patients were taking valproic acid. Primary or secondary metabolic abnormalities likely represent a prominent finding in these patients. Differential diagnoses involving mitochondrial dysfunction should receive serious consideration. Findings such as carnitine deficiency can be identified and treated. A systematic approach for such testing is needed. A prospective evaluation at our institution is planned.  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