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   49346篇
  免费   2989篇
  国内免费   240篇
耳鼻咽喉   500篇
儿科学   926篇
妇产科学   637篇
基础医学   6424篇
口腔科学   1080篇
临床医学   5182篇
内科学   10845篇
皮肤病学   990篇
神经病学   5642篇
特种医学   2529篇
外科学   8265篇
综合类   300篇
一般理论   13篇
预防医学   2267篇
眼科学   647篇
药学   2942篇
中国医学   69篇
肿瘤学   3317篇
  2023年   431篇
  2022年   689篇
  2021年   1414篇
  2020年   838篇
  2019年   1269篇
  2018年   1432篇
  2017年   1125篇
  2016年   1350篇
  2015年   1552篇
  2014年   1966篇
  2013年   2433篇
  2012年   3904篇
  2011年   3938篇
  2010年   2336篇
  2009年   2107篇
  2008年   3361篇
  2007年   3442篇
  2006年   3184篇
  2005年   3132篇
  2004年   2779篇
  2003年   2656篇
  2002年   2390篇
  2001年   449篇
  2000年   350篇
  1999年   403篇
  1998年   479篇
  1997年   362篇
  1996年   290篇
  1995年   226篇
  1994年   221篇
  1993年   168篇
  1992年   142篇
  1991年   134篇
  1990年   100篇
  1989年   94篇
  1988年   97篇
  1987年   71篇
  1986年   78篇
  1985年   75篇
  1984年   104篇
  1983年   84篇
  1982年   77篇
  1981年   61篇
  1980年   55篇
  1979年   49篇
  1978年   48篇
  1977年   50篇
  1976年   47篇
  1975年   50篇
  1974年   48篇
排序方式: 共有10000条查询结果,搜索用时 5 毫秒
991.
992.
993.
994.
995.
996.
Maintaining and improving fitness are associated with a lower risk of premature death from cardiovascular disease. Patients with schizophrenia are known to exercise less and have poorer health behaviors than average. Physical fitness and physiological regulation during exercise tasks have not been investigated to date among patients with schizophrenia. We studied autonomic modulation in a stepwise exhaustion protocol in 23 patients with schizophrenia and in matched controls, using spirometry and lactate diagnostics. Parameters of physical capacity were determined at the aerobic, anaerobic, and vagal thresholds (VT), as well as for peak output. VT was correlated with psychopathology, as assessed by the Positive and Negative Syndrome Scale, with the inflammatory markers IL-1β, IL-6, and TNF-α and with peak output. The MANOVA for heart and breathing rates, as well as for vagal modulation and complexity behavior of heart rate, indicated a profound lack of vagal modulation at all intensity levels, even after the covariate carbon monoxide concentration was introduced as a measure of smoking behavior. Significantly decreased physical capacity was demonstrated at the aerobic, anaerobic, and VT in patients. After the exercise task, reduced vagal modulation in patients correlated negatively with positive symptoms and with levels of IL-6 and TNF-α. This study shows decreased physical capacity in patients with schizophrenia. Upcoming intervention studies need to take into account the autonomic imbalance, which might predispose patients to arrhythmias during exercise. Results of inflammatory parameters are suggestive of a reduced activity of the anti-inflammatory cholinergic pathway in patients, leading to a pro-inflammatory state.Key words: heart rate, physical exercise, respiration, schizophrenia, vagal threshold, cardiac death, inflammation, physical fitness  相似文献   
997.
The pulvinar nuclei of the thalamus are hypothesized to coordinate attentional selection in the visual cortex. Different models have, however, been proposed for the precise role of the pulvinar in attention. One proposal is that the pulvinar mediates shifts of spatial attention; a different proposal is that it serves the filtering of distractor information. At present, the relation between these possible operations and their relative importance in the pulvinar remains unresolved. We address this issue by contrasting these proposals in two fMRI experiments. We used a visual search paradigm that permitted us to dissociate neural activity reflecting shifts of attention from activity underlying distractor filtering. We find that distractor filtering, but not the operation of shifting attention, is associated with strong activity enhancements in dorsal and ventral regions of the pulvinar as well as in early visual cortex areas including the primary visual cortex. Our observations indicate that distractor filtering is the preponderant attentional operation subserved by the pulvinar, presumably mediated by a modulation of processing in visual areas where spatial resolution is sufficiently high to separate target from distractor input. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
998.
Abstract

The aim of the present study was to investigate the use and attitudes toward standardized assessment tools among clinicians in a public mental health service in Norway. A total of 606 clinicians provided feedback on their use and attitudes regarding psychometric qualities of such tools, their practicality, and their benefit over clinical judgment alone using the Attitudes toward Standardized Assessment (ASA) Scales. Clinicians working in the adult mental health field scored significantly higher on use of diagnostic interviews, pre–post evaluations, and ongoing evaluations, whereas clinicians working in the child/adolescent mental health field scored significantly higher on use of screening instruments and held more positive attitudes towards using standardized assessment tools. Attitudes toward standardized assessment tools predicted use of such tools, and results were found to be similar to a study on US clinicians. Whereas the US study only found attitudes regarding the practicality of using such instrument as an independent predictor of assessment use, the current study found that attitudes regarding psychometric qualities of such tools, their practicality, and their benefit over clinical judgment alone were independent predictors of use.  相似文献   
999.
Acetylcholinesterase inhibitors (AChEIs) are drugs that increase synaptic acetylcholine (ACh) concentrations and are under investigation as treatments for symptoms accompanying Alzheimer's disease. The goal of this work was to use PET imaging to evaluate alterations of in vivo α4β2 nicotinic acetylcholine receptor (nAChR) binding induced by the AChEIs physostigmine (PHY) and galanthamine (GAL). The α4β2 nAChR‐specific radioligand [18F]nifene was used to examine the effects of 0.1–0.2 mg/kg PHY, 5 mg/kg GAL, and saline in three separate experiments all performed on each of two rat subjects. A 60‐min bolus‐infusion protocol was used with drug administered after 30 min. Data from the thalamus and cortex were analyzed with a graphical model accounting for neurotransmitter activation using the cerebellum as a reference region to test for transient competition with bound [18F]nifene. Significant [18F]nifene displacement was detected in both regions during one PHY and both GAL studies, while no significant competition was observed in both saline studies. This preliminary work indicates the viability of [18F]nifene in detecting increases in synaptic ACh induced by AChEIs. Synapse 67:882–886, 2013. © 2013 Wiley Periodicals, Inc.  相似文献   
1000.
Metabolic syndrome (MetS) is an important risk factor for the development of type-2 diabetes and coronary artery disease. We aimed to compare the MetS prevalence in patients with borderline personality disorder (BPD) with comparison subjects followed in primary care from a similar region. One hundred and thirty-five BPD patients according to DSM-IV diagnostic criteria were compared to 1009 subjects from primary care. We used the American Heart Association/National Heart, Lung and Blood Institute criteria to determine the rate of MetS. The age-standardized prevalence of MetS was more than double in patients with BPD compared to comparison subjects (23.3 vs. 10.6 %, p < 0.05). Regarding individual MetS criteria, hyperglycemia was significantly more prevalent in both genders (p < 0.05). Abdominal obesity (p < 0.05) and hypertriglyceridemia (p < 0.05) were significantly higher only in women with BPD. Within BPD patients, an increased rate of MetS was associated with higher BMI (p = 0.004), age (p = 0.03), treatment with second-generation antipsychotics (quetiapine, olanzapine and clozapine; p = 0.032), dysthymia (p = 0.031), panic disorder (p = 0.032), benzodiazepine dependency (p = 0.015) and binge eating disorder p = 0.02). Our results demonstrate an increased MetS rate, dysregulated glucose and lipid metabolism in patients with BPD. Cardiometabolic monitoring and careful screening for physical health conditions among people with BPD is warranted.  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