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   4319篇
  免费   234篇
  国内免费   1篇
  2024年   12篇
  2023年   68篇
  2022年   73篇
  2021年   108篇
  2020年   143篇
  2019年   118篇
  2018年   250篇
  2017年   230篇
  2016年   217篇
  2015年   132篇
  2014年   152篇
  2013年   567篇
  2012年   323篇
  2011年   338篇
  2010年   218篇
  2009年   95篇
  2008年   294篇
  2007年   213篇
  2006年   213篇
  2005年   114篇
  2004年   105篇
  2003年   81篇
  2002年   66篇
  2001年   27篇
  2000年   59篇
  1999年   29篇
  1998年   19篇
  1997年   15篇
  1996年   15篇
  1995年   12篇
  1994年   17篇
  1993年   13篇
  1992年   15篇
  1991年   8篇
  1990年   15篇
  1989年   11篇
  1988年   7篇
  1987年   15篇
  1985年   7篇
  1981年   6篇
  1979年   8篇
  1978年   6篇
  1976年   7篇
  1975年   5篇
  1974年   6篇
  1973年   11篇
  1971年   12篇
  1968年   14篇
  1966年   7篇
  1965年   6篇
排序方式: 共有4554条查询结果,搜索用时 31 毫秒
951.
Frailty is a dynamic clinical syndrome considered as part of an age-associated continuum of severity, including pre-frailty as an intermediate frailty status with potential reversibility to robustness. The main purpose of this study was to analyse the relationship between the different domains of quality of life, functional dependence and depressive symptomatology in older adults diagnosed as pre-frail, before progression to frailty occurs. Logistic regression analyses were conducted to examine whether sex, age, level of education and scores in the Geriatric Depression Scale 15-item Short Form (GDS-SF) and the Instrumental Activities of Daily Living Lawton scale determine the worst score in the WHOQOL-BREF (World Health Organization Quality of Life) in older adults meeting one or two frailty phenotypic criteria. Depressive symptomatology (GDS-SF score) was the main determinant of poor quality of life in both groups, and in all areas of WHOQOL-BREF. Age was only associated with poor satisfaction with own health. Female sex and low educational level were linked to low physical QOL and poor self-rated health, respectively, but only in older adults meeting one frailty criterion. Association between functional status and WHOQOL-BREF scores was only found in the univariate analysis. These results underline the importance of identifying multiple aspects, but mainly the presence of depressive symptomatology, as risk factors for all dimensions of quality of life in the pre-frailty process, where interventions might be targeted to reduce the progression of pre-frailty and frailty in older adults.  相似文献   
952.
Humans have developed a specific capacity to rapidly perceive and anticipate other people’s facial expressions so as to get an immediate impression of their emotional state of mind. We carried out two experiments to examine the perceptual and memory dynamics of facial expressions of pain. In the first experiment, we investigated how people estimate other people’s levels of pain based on the perception of various dynamic facial expressions; these differ both in terms of the amount and intensity of activated action units. A second experiment used a representational momentum (RM) paradigm to study the emotional anticipation (memory bias) elicited by the same facial expressions of pain studied in Experiment 1. Our results highlighted the relationship between the level of perceived pain (in Experiment 1) and the direction and magnitude of memory bias (in Experiment 2): When perceived pain increases, the memory bias tends to be reduced (if positive) and ultimately becomes negative. Dynamic facial expressions of pain may reenact an “immediate perceptual history” in the perceiver before leading to an emotional anticipation of the agent’s upcoming state. Thus, a subtle facial expression of pain (i.e., a low contraction around the eyes) that leads to a significant positive anticipation can be considered an adaptive process—one through which we can swiftly and involuntarily detect other people’s pain.  相似文献   
953.
The study explores whether people are more inclined to accept a conclusion that confirms their prior beliefs and reject one they personally object to even when both follow the same logic. Most of the prior research in this area has relied on the informal reasoning paradigm; in this study, however, we applied a formal reasoning paradigm to distinguish between cognitive and motivational mechanisms leading to myside bias in reasoning on value-laden topics (in this case abortions). Slovak and Polish (N?=?387) participants indicated their attitudes toward abortion and then evaluated logical syllogisms with neutral, pro-choice, or pro-life content. We analysed whether participants’ prior attitudes influenced their ability to solve these logically identical reasoning tasks and found that prior attitudes were the strongest predictor of myside bias in evaluating both valid and invalid syllogisms, even after controlling for logical validity (the ability to solve neutral syllogisms) and previous experience of logic.  相似文献   
954.
Stress regulation during pregnancy is considered to be connected to the timing of labour initiation. Although increasing knowledge is emerging on the regulation of parturition, there is currently no way to predict the start of spontaneous labour in women. The main aim of this study was to assess pain threshold and the sympathetic nervous system response to cold pain in relation to the onset of labour in healthy pregnant women. Ninety-three pregnant women were recruited and assessed for skin conductance (SC) activity during a cold pressor test in gestational week 38. Pain threshold and cold endurance were also measured and the results were compared with data obtained from hospital records. Seventy-four women had a spontaneous labour onset and a valid SC measurement. SC activity during the cold pressor test decreased significantly with the number of days left to spontaneous parturition. This may indicate a gradual decrease in sympathetic autonomic nervous system reactivity even during the last weeks of pregnancy. Measuring SC activity during mild stress provocation is a rapid and non-invasive means to study variation in sympathetic reactivity during pregnancy, and may be useful in research on stress regulation in pregnancy and its relation to labour initiation.  相似文献   
955.
This study examined the relationship between several cognitive-affective factors of the fear-avoidance model of pain, the big five model of personality, and functional impairment in fibromyalgia (FM). Seventy-four FM patients completed the NEO Five-Factor Inventory, the Pain Catastrophizing Scale, the Pain Anxiety Symptoms Scale-20, the Pain Vigilance and Awareness Questionnaire, and the Impairment and Functioning Inventory. Results indicated that the cognitive-affective factors of pain are differentially associated with personality traits. Neuroticism and conscientiousness were significant predictors of pain catastrophizing, and neuroticism, openness, and agreeableness were significant predictors of pain anxiety. Personality traits did not contribute significantly to vigilance to pain. The effect of neuroticism upon pain anxiety was mediated by pain catastrophizing, and neuroticism showed a trend to moderate the relationship between impairment and pain anxiety. Results support the fear-avoidance model of pain. Implications of the findings for the understanding and management of FM are discussed.  相似文献   
956.
The main objective of this study is to settle a rigorous field of decision analysis for rubber tree clones selection. Nowadays, there does not exist any process based upon a rigorous method to select the best clone to be plant in order to get the highest return on investment. The only known selection method is to use the experience of different protagonists acting in the plantation. So, we need a tool that takes into account very important criteria in order to achieve the main objective. This goal is achieved by using multicriterion analysis methods to the clone selection. The ranking procedure uses Elimination and Choice Expressing the Reality (ELECTRE III). For each criterion, indifference and preference thresholds are determined after establishing the relative importance of each criterion including rubber tapping, cumulative production during 15 years, cumulative production between 15 and 25 years, wind resistance, disease resistance, physiological resistance, grafting and quality of the rubber. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
957.
We used several cue–target SOAs (100, 500, 1000 ms) and three different degrees of cue predictability (Non-predictive-50%, Predictive-75%, Counter-predictive-25%), to investigate the role of awareness of cue–target predictability on cueing effects. A group of participants received instructions about the informative value of the cue, while another group did not receive such instructions. Participants were able to extract the predictive value of a spatially peripheral cue and use it to orient attention, whether or not specific instructions about the predictive value of the cue were given, and no matter their ability to correctly report it in a post-test questionnaire. In the non-predictive block, bad estimators who received no instructions showed regular cueing effects, while good estimators exhibited smaller and non-significant facilitatory effects at the short SOA and an absence of significant IOR at longer SOAs. However, for the instructions group, the pattern of results reversed.  相似文献   
958.
The present study examined the relationship between feelings provoked by child sexual abuse (CSA) and posttraumatic stress disorder (PTSD) symptom scores in a sample of 163 female survivors of CSA. Finkelhor and Browne's traumagenic dynamics model was applied. The interactive effects of provoked feelings with perpetrator age and the existence of abuse disclosure were also studied. Results showed an overall relationship between feelings provoked by CSA and PTSD symptom scores. Feelings of stigma, betrayal, and powerlessness as a result of CSA were associated with PTSD symptom score when the entire group of CSA victims was analyzed. The role of traumatic sexualization was relevant only when analyzed in interaction with the age of the perpetrator and disclosure. The relationship between traumatic sexualization and PTSD symptom scores was only significant when the abuse was committed by an adult perpetrator and when a disclosure was made during the time of abuse, or a short time after the abuse had occurred.  相似文献   
959.
The ability of neurons to modify their synaptic strength in an activity-dependent manner has a crucial role in learning and memory processes. It has been proposed that homeostatic forms of plasticity might provide the global regulation necessary to maintain synaptic strength and plasticity within a functional dynamic range. Similarly, it is considered that the capacity of synapses to express plastic changes is itself subject to variation dependent on previous experience. In particular, training in several behavioral tasks modifies the possibility to induce long-term potentiation (LTP). Our previous studies in the insular cortex (IC) have shown that induction of LTP in the basolateral amygdaloid nucleus (Bla)-IC projection previous to conditioned taste aversion (CTA) training enhances the retention of this task. The aim of the present study was to analyze whether CTA training modifies the ability to induce subsequent LTP in the Bla-IC projection in vivo. Thus, CTA trained rats received high frequency stimulation in the Bla-IC projection in order to induce LTP 48, 72, 96 and 120 h after the aversion test. Our results show that CTA training prevents the subsequent induction of LTP in the Bla-IC projection, for at least 120 h after CTA training. We also showed that pharmacological inhibition of CTA consolidation with anisomycin (1 μl/side; 100 μg/μl) prevents the CTA effect on IC-LTP. These findings reveal that CTA training produces a persistent change in the ability to induce subsequent LTP in the Bla-IC projection in a protein-synthesis dependent manner, suggesting that changes in the ability to induce subsequent synaptic plasticity contribute to the formation and persistence of aversive memories.  相似文献   
960.
Variation in intracellular calcium concentration regulates the induction of long-term synaptic plasticity and is associated with a variety of memory/retrieval and learning paradigms. Accordingly, impaired calcium mobilization from internal deposits affects synaptic plasticity and cognition in the aged brain. During taste memory formation several proteins are modulated directly or indirectly by calcium, and recent evidence suggests the importance of calcium buffering and the role of intracellular calcium deposits during cognitive processes. Thus, the main goal of this research was to study the consequence of hampering changes in cytoplasmic calcium and inhibiting SERCA activity by BAPTA-AM and thapsigargin treatments, respectively, in the insular cortex during different stages of taste memory formation. Using conditioned taste aversion (CTA), we found differential effects of BAPTA-AM and thapsigargin infusions before and after gustatory stimulation, as well as during taste aversive memory consolidation; BAPTA-AM, but not thapsigargin, attenuates acquisition and/or consolidation of CTA, but neither compound affects taste aversive memory retrieval. These results point to the importance of intracellular calcium dynamics in the insular cortex during different stages of taste aversive memory formation.  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