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   933篇
  免费   54篇
  国内免费   55篇
  2024年   3篇
  2023年   35篇
  2022年   41篇
  2021年   66篇
  2020年   32篇
  2019年   48篇
  2018年   46篇
  2017年   21篇
  2016年   34篇
  2015年   54篇
  2014年   57篇
  2013年   58篇
  2012年   51篇
  2011年   49篇
  2010年   32篇
  2009年   50篇
  2008年   54篇
  2007年   48篇
  2006年   19篇
  2005年   20篇
  2004年   19篇
  2003年   19篇
  2002年   14篇
  2001年   9篇
  2000年   13篇
  1999年   15篇
  1998年   10篇
  1997年   13篇
  1996年   7篇
  1995年   7篇
  1994年   9篇
  1993年   17篇
  1992年   5篇
  1991年   7篇
  1990年   10篇
  1989年   3篇
  1988年   5篇
  1987年   6篇
  1986年   4篇
  1985年   6篇
  1984年   6篇
  1983年   2篇
  1982年   6篇
  1981年   5篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1970年   1篇
排序方式: 共有1042条查询结果,搜索用时 31 毫秒
31.
This study was designed to identify psychophysical channels responsible for the detection of hand-transmitted vibration. Perception thresholds for vibration (16, 31.5, 63 and 125?Hz sinusoidal for 600?ms) at the distal phalanx of the middle finger and the whole hand were determined with and without simultaneous masking stimuli (1/3 octave bandwidth Gaussian random vibration centered on either 16?Hz or 125?Hz for 3000?ms, varying in magnitude 0 to 30?dB above threshold). At all frequencies from 16 to 125?Hz, absolute thresholds for the hand were significantly lower than those for the finger. Changes in threshold as a function of masker level were used to estimate the thresholds of three psychophysical channels (i.e. P, NP I, and NP II channels). Increased vibrotactile sensitivity of the hand compared to the finger seems to be not entirely due to increased spatial summation via the Pacinian system (P channel); non-Pacinian system (NP I and NP II channels) also contributed to perception. Differing transmission of vibration between the hand and the finger may have also influenced the thresholds.  相似文献   
32.
CHF5074, a new microglial modulator, attenuates memory deficit in Alzheimer's disease transgenic mice. In this study, the effect of an acute or subacute CHF5074 treatment on in vivo novel object recognition test and on [3H]Acetylcholine (ACh) and GABA release in pre‐plaque (7‐month‐old) Tg2576 mice have been compared with those induced by the γ‐secretase inhibitor LY450139 (semagacestat). Vehicle‐treated Tg2576 mice displayed an impairment of recognition memory compared with wild‐type animals. This impairment was recovered in transgenic animals acutely treated with CHF5074 (30 mg/kg), while LY450139 (1, 3, 10 mg/kg) was ineffective. In frontal cortex synaptosomes from vehicle‐treated Tg2576 mice, K+‐evoked [3H]ACh release was lower than that measured in wild‐type mice. This reduction was absent in transgenic animals subacutely treated with CHF5074 (30 mg/kg daily for 8 days), while it was slightly, not significantly, amplified by LY450139 (3 mg/kg daily for 8 days). There were no differences between the groups on spontaneous [3H]ACh release as well as spontaneous and K+‐evoked GABA release. These results suggest that CHF5074 has beneficial effects on visual memory and cortical cholinergic dysfunctions in pre‐plaque Tg2576 mice. Together with previous findings, these data suggest that CHF5074 could be a possible candidate for early Alzheimer's disease therapeutic regimens.  相似文献   
33.
When watching an actor manipulate objects, observers, like the actor, naturally direct their gaze to each object as the hand approaches and typically maintain gaze on the object until the hand departs. Here, we probed the function of observers'' eye movements, focusing on two possibilities: (i) that observers'' gaze behaviour arises from processes involved in the prediction of the target object of the actor''s reaching movement and (ii) that this gaze behaviour supports the evaluation of mechanical events that arise from interactions between the actor''s hand and objects. Observers watched an actor reach for and lift one of two presented objects. The observers'' task was either to predict the target object or judge its weight. Proactive gaze behaviour, similar to that seen in self-guided action–observation, was seen in the weight judgement task, which requires evaluating mechanical events associated with lifting, but not in the target prediction task. We submit that an important function of gaze behaviour in self-guided action observation is the evaluation of mechanical events associated with interactions between the hand and object. By comparing predicted and actual mechanical events, observers, like actors, can gain knowledge about the world, including information about objects they may subsequently act upon.  相似文献   
34.
??????? 目的 了解门诊患者对就医服务感受度影响因素,以期提高患者满意度。 方法 现场问卷调查法、专家访谈法。 结果 患者在门诊过程中最为关注的就诊流程、等候时间、就医环境、医德医风四个因素,非常看重医护人员服务规范,服务流程便捷流畅。病情不同患者对等候时间要求不同,对医院熟悉程度与就诊环境感受度不同。结论 在门诊服务中为患者提供便捷流畅、规范化的服务,同时应注重患者的不同服务需求。  相似文献   
35.
The oxidization of fatty acids generates many volatile compounds forming an aroma, but little is known whether mammals use gustatory sense to detect the oxidized products as a taste or only use olfactory sense to detect as an aroma. We examined in this study the effect of aqueous extracts of the compounds from autoxidized arachidonic acid (AA) ethyl ester or hexanal which is the predominant component generated from oxidized AA by the anosmic mouse licking performance to a tastant. The addition of the water extract from oxidized AA or hexanal to a quinine hydrochloride (QHCl) solution decreased the anosmic mice licking frequency at several concentrations of QHCl. Hexanal also reduced the licking frequency of anosmic mice conditioned to avoid MSG at several concentrations of monosodium glutamate (MSG). These results suggest that hexanal would affect mouse taste perception to QHCl and MSG via the gustatory sensation.  相似文献   
36.
37.
景观感知作为自然教育非常重要的组成部分,其研究内容受到广泛关注,但现有研究仍处于初步阶段,未对自然教育环境设计起到应有的支撑作用。从景观感知角度,综合环境教育学、环境心理学及行为心理学等相关理论,对基于景观感知的自然教育环境的营建提出了针对性原则及策略,并着重探讨影响景观感知的设计要素。首次从景观感知角度对自然教育环境设计进行探讨,对自然教育环境的营建具有指导意义。 关键词:风景园林;自然教育;景观感知  相似文献   
38.
Guanylyl cyclase C (GC‐C) is found in brain regions where dopamine is expressed. We characterized a mouse in which GC‐C was knocked out (KO) that was reported to be a model of attention deficit hyperactivity disorder (ADHD). We re‐examined this model and controlled for litter effects, used 16 to 23 mice per genotype per sex and assessed an array of behavioral and neurochemical outcomes. GC‐C KO mice showed no phenotypic differences from wild‐type mice on most behavioral tests, or on striatal or hippocampal monoamines, and notably no evidence of an ADHD‐like phenotype. KO mice were impaired on novel object recognition, had decreased tactile startle but not acoustic startle, and females had increased latency on cued training trials in the Morris water maze, but not hidden platform spatial learning trials. Open‐field activity showed small differences in females but not males. The data indicate that the GC‐C KO mouse with proper controls and sample sizes has a moderate cognitive and startle phenotype but has no ADHD‐like phenotype.  相似文献   
39.
40.
ABSTRACT

Smog pollution has received widely attention in recent years due to its negative effects. There is consensus that the motor vehicle exhaust emission is one of the sources of smog pollution and reduced private car use would significantly improve the air quality and alleviate the smog pollution problem. In this research, we aim to investigate how public smog knowledge and risk perception (physical health risk perception and mental health risk perception) affect public attitude and intention to reduce car use. A questionnaire survey of 334 randomly sampled respondents was designed to test these relationships. The results show that public smog knowledge is positively and significantly related to physical health risk perception, mental health risk perception, attitude and intention to reduce car use. Public smog knowledge has the largest impact on intention to reduce car use. Furthermore, physical health risk perception and mental health risk perception are positively and significantly associated with attitude and intention to reduce car use. In addition, the results also indicated that public smog knowledge is at a low level. Based on the results, implications and suggestions for future research were discussed.  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