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   3656篇
  免费   47篇
  3703篇
  2024年   39篇
  2023年   55篇
  2022年   46篇
  2021年   66篇
  2020年   100篇
  2019年   87篇
  2018年   161篇
  2017年   154篇
  2016年   145篇
  2015年   85篇
  2014年   109篇
  2013年   392篇
  2012年   236篇
  2011年   258篇
  2010年   156篇
  2009年   62篇
  2008年   214篇
  2007年   165篇
  2006年   165篇
  2005年   79篇
  2004年   85篇
  2003年   57篇
  2002年   59篇
  2001年   50篇
  2000年   74篇
  1999年   39篇
  1998年   20篇
  1997年   19篇
  1992年   23篇
  1991年   20篇
  1990年   46篇
  1989年   29篇
  1988年   16篇
  1987年   28篇
  1986年   32篇
  1985年   24篇
  1984年   22篇
  1983年   16篇
  1981年   11篇
  1979年   13篇
  1978年   12篇
  1975年   15篇
  1974年   17篇
  1973年   21篇
  1972年   14篇
  1971年   19篇
  1970年   15篇
  1968年   11篇
  1967年   11篇
  1966年   9篇
排序方式: 共有3703条查询结果,搜索用时 15 毫秒
951.
Psychoanalysis recruits the power of the spoken word to modify the subject's relationship with his or her own unconscious psychic processes. It helps the analysand to reclaim for his or her words the psychic integrity that was lost or never achieved due to the power of defensive dissociation and repression. The psychoanalytic dialogue and the working through mediated by it lead to the elaboration of self-narratives and interpretive understandings, which contribute to the transformation of the subject's self-experience. Such transformation is conditioned by earlier integration of experiences of satisfaction in the context of bodily dialogues and speech with primary objects.  相似文献   
952.
It is very common to find meta-analyses in which some of the studies compare 2 groups on continuous dependent variables and others compare groups on dichotomized variables. Integrating all of them in a meta-analysis requires an effect-size index in the same metric that can be applied to both types of outcomes. In this article, the performance in terms of bias and sampling variance of 7 different effect-size indices for estimating the population standardized mean difference from a 2 x 2 table is examined by Monte Carlo simulation, assuming normal and nonnormal distributions. The results show good performance for 2 indices, one based on the probit transformation and the other based on the logistic distribution.  相似文献   
953.
954.
Neonatal handling is known to induce long-lasting changes in behavioral and neuroendocrine responses to stress. Since the central noradrenergic system participates in the adaptive responses to stressful conditions we have analyzed the effects of postnatal handling on beta-adrenoceptor binding sites and isoprenaline- and forskolin-stimulated cyclic AMP accumulation in cerebral cortex, hippocampus and cerebellum of rats at 1 and 3 months of age. Handled animals showed reduced emotional reactivity and lower ACTH and corticosterone secretion after stress. Binding studies using [(3) H]CGP12-177 revealed increased beta-adrenoceptor binding sites in handled rats in cerebellum and cerebral cortex with no changes in hippocampus, and decreased affinity in all cerebral regions. Handling reduced basal levels of cyclic AMP in hippocampus and cerebellum but not in cerebral cortex. The concentration-response curves of cyclic AMP to isoprenaline were displaced to the right in cerebellum of handled rats without differences in Emax; however, Emax was significantly reduced in cerebral cortex and hippocampus. Direct stimulation of the catalytic subunit of adenylyl cyclase by forskolin reduced the efficiency in hippocampus and cerebellum, but not in cerebral cortex of handled animals. It is concluded that neonatal handling reduces the binding properties of beta-adrenoceptor and its primary biochemical responses in the young rat brain, which may account for the reduced responsiveness to stress attained in the handled rats, and may explain the persistence of the effect. The present study emphasizes the role of the central noradrenergic system in modulating the behavioral and neurendocrine responses to neonatal handling.  相似文献   
955.
We have reported that exposure of preweaning male and female rats to a model of unpredictable mild physical stressors (Neo-A) can decrease the behavioral and hormonal responses to acute and chronic stress as adults. In this paper we have analyzed the effect of Neo-A on development of social behaviors, including aggressiveness, social dominance, and sexual behavior in adulthood. The subjects were divided into two groups: Neo-A (daily exposed to unpredictable mild stresses- from day 2 up to day 15 of suckling; n = 30 litters) and controls (C) (undisturbed rats, except for testing, during the same period of life; n = 26 litters). When day 6 pups were submitted to a social clustering test the Neo-A group showed a higher rate of litter-mate clustering than C. The 35 days Neo-A males and Neo-A females submitted to a social behavior test after 24 h of social isolation also showed higher scores of time spent in active social interaction than controls, as well as a higher ratio of animals showing aggressive playing. A second social behavior test performed after 48 h of social isolation at days 75-80 of age revealed that only Neo-A females displayed increased social behavior and aggressive behaviors, whereas controls did not. A water competition test performed at 24 and 48 h after water deprivation showed that Neo-A adult males spent more time in possession of the drinking device and drank more frequently than C. When adult proestrous females were exposed to a sexual behavior test, the Neo-A group showed shorter latency and higher scores of lordosis quotient. These results support the view that exposure to this model of repeated mild stress early in life stimulates the development of social behavior, dominance and sexual behavior.  相似文献   
956.
Three studies examined mental model generation after preexposure to uncontrollability and in a depressive state. The purpose of the experiments was to test the implications of the cognitive exhaustion model, applying an explicit conceptualization of social mental models and a process-tracing method developed by U. von Hecker (1997). An experimental situation was created for observation of consecutive, rule-based construction steps as a function of input diagnosticity, and for the quality assessment of constructed mental models. The findings show that participants preexposed to uncontrollability, as well as depressed students, were able, as were controls, to identify rule-relevant information needed for model construction. However, they were less able than control participants to engage in a more cognitively demanding and generative step of processing (i.e., in integrating the pieces of input information into a coherent mental model of sentiment relations).  相似文献   
957.
Brain histamine is exclusively contained within and released from neurons whose cell bodies are clustered in the tuberomammillary nucleus (TM) of the posterior hypothalamus. This experiment examined the effects of a transient inactivation of the TM on inhibitory avoidance learning. Rats with chronically implanted cannulae were tested on a 1-trial step-through avoidance task. Immediately following training, the rats received unilateral intra-TM infusions (0.5 microl) of lidocaine (5 or 20 microg). Control groups included vehicle-injected rats and a group given an injection of 20 microg lidocaine 5 h after training. When tested 24 h later, rats treated with 20 microg lidocaine exhibited longer step-through latencies than vehicle-treated controls, indicative of superior learning of the task. The failure of the delayed post-trial injection of lidocaine to significantly influence step-through latencies indicates that the compound influenced learning by modulating memory storage processes rather than by acting on performance variables during retrieval of the task. Thus, inactivation of the TM by lidocaine can exert facilitatory effects on mnemonic processing, which might be related to a temporary reduction of histaminergic activity during the early phase of memory consolidation.  相似文献   
958.
In stimulus blocking the previous conditioning to one stimulus, A, followed by conditioning to the compound stimulus, AB, results in less conditioning to the other stimulus, B. Three experiments were performed to study the effect of the prior pairing of a stimulus A (noisy bottle) with lithium chloride followed by stimulus AB (saccharin plus noisy bottle) and lithium chloride pairings upon the strength of the aversion to the target stimuls B (saccharin) in NA-depleted and control rats. The results obtained were not in keeping with a "blocking" explanation since enhancement, rather than blocking, of the saccharin aversion was obtained, and confirm several recent demonstrations of the "anti-blocking" effect from investigations using the conditioned suppression procedure. DSP4 treatment attenuated the aversion-enhancement ("anti-blocking") effects in all three experiments. The possibility that DSP4-induced noradrenaline depletions may cause some disruption of between-CS associations leading to a lesser higher order conditioning or stimulus generalisation is discussed and the present findings do add further evidence to the conclusion that noradrenaline is intimately involved in attentional processes.  相似文献   
959.
The experiment is a partial replication of a study conducted by Trope. It investigates the effects of two person characteristics (achievement motive and perceived own ability) and two task characteristics (difficulty and diagnostic value about own ability) on choice among achievement tasks. In accordance with the results of Trope, it was found that high-diagnostic tasks were preferred to low-diagnostic tasks, independent of their difficulty. Trope's finding that high resultant achievers choose high-diagnostic tasks over low-diagnostic tasks to a greater extent than low resultant achievers was not replicated. However, the perceived degree of own ability affected choice behavior: When easy and difficult tasks were both high in diagnosticity, subjects high in perceived ability preferred difficult over easy tasks, whereas subjects low in perceived ability preferred easy over difficult tasks. From this latter finding it is concluded that a self-informational conception of choice behavior has to include the subjective probability of success at tasks as a determinant of choice, in addition to objective difficulty and diagnostic value.  相似文献   
960.
In a total of fifty cerebrospinal fluids, such immunoglobulins as IgG, IgA, and IgM were quantitatively determined in a parallel manner on LC partigen plates and on slides (SEVAC set of means of testing). The comparability of the two methods of test proved excellent with good precision. The sensitivity of IgA determination on slides was made higher, the measurability of all precipitates was improved, and the economic advantage increased by cutting the cost of one determination fifteen times.  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