全文获取类型
收费全文 | 22313篇 |
免费 | 85篇 |
国内免费 | 8篇 |
出版年
2023年 | 21篇 |
2022年 | 13篇 |
2021年 | 29篇 |
2020年 | 38篇 |
2019年 | 45篇 |
2018年 | 3579篇 |
2017年 | 2887篇 |
2016年 | 2322篇 |
2015年 | 227篇 |
2014年 | 118篇 |
2013年 | 204篇 |
2012年 | 646篇 |
2011年 | 2485篇 |
2010年 | 2584篇 |
2009年 | 1521篇 |
2008年 | 1781篇 |
2007年 | 2260篇 |
2006年 | 65篇 |
2005年 | 259篇 |
2004年 | 210篇 |
2003年 | 147篇 |
2002年 | 111篇 |
2001年 | 79篇 |
2000年 | 101篇 |
1999年 | 45篇 |
1998年 | 38篇 |
1997年 | 36篇 |
1996年 | 20篇 |
1994年 | 14篇 |
1992年 | 20篇 |
1991年 | 23篇 |
1990年 | 42篇 |
1989年 | 31篇 |
1988年 | 14篇 |
1987年 | 24篇 |
1986年 | 31篇 |
1985年 | 25篇 |
1984年 | 25篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1979年 | 14篇 |
1978年 | 13篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 20篇 |
1972年 | 14篇 |
1971年 | 20篇 |
1970年 | 15篇 |
1967年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
Christina Grape Maria Sandgren Lars-Olof Hansson Mats Ericson T?res Theorell 《Integrative Physiological and Behavioral Science》2003,38(1):65-74
This study explored the possible beneficial effects of singing on well-being during a singing lesson. Eight amateur (2m, 6f, age 28-53 yrs) and eight professional (4m, 4f, age 26-49 yrs) singers who had been attending singing lessons for at least six months were included. Continuous ECG was recorded and computerized spectral analysis was performed. Serum concentrations of TNF-alpha, prolactin, cortisol, and oxytocin were measured before and 30 min after the lesson. Five visual analogue scales (VAS, sad-joyful, anxious-calm, worried-elated, listless-energetic, and tense-relaxed) were scored before and after the lesson. In addition, a semi-structured interview was performed. Heart rate variability analyses showed significant changes over time in the two groups for total power, and low and high frequency power. Power increased during singing in professionals, whereas there were no changes in amateurs. This indicates an ability to retain more "heart-brain connection." i.e., more cardio-physiological fitness for singing in professional singers, compared to amateur singers. Serum concentration of TNF-alpha increased in professionals after the singing lesson, whereas the concentration in amateurs decreased. Serum concentrations of prolactin and cortisol increased after the lesson in the group of men and vice versa for women. Oxytocin concentrations increased significantly in both groups after the singing lesson. Amateurs reported increasing joy and elatedness (VAS), whereas professionals did not. However, both groups felt more energetic and relaxed after the singing lesson. The interviews showed that the professionals were clearly achievement-oriented, with focus on singing technique, vocal apparatus and body during the lesson. The amateurs used the singing lessons as a means of self-actualization and self-expression as a way to release emotional tensions. In summary, in this study, singing during a singing lesson seemed to promote more well-being and less arousal for amateurs compared to professional singers, who seemed to experience less well-being and more arousal. 相似文献
182.
In three experiments, we investigated the influence of the overt performance of signs on memory. Deaf and hearing participants
studied lists of action phrases (Experiment 1) or nouns (Experiment 2) under standard verbal instruction, under the instructions
to sign the verbal phrase, to symbolically perform the denoted action, or to carry out a prototypical action corresponding
to each noun. Higher recall and recognition performances were observed when actions were performed than in the verbal encoding
condition, and signing was as effective for memory as was enactment. Thus, overt signing can induce an enactment effect. In
contrast, Experiment 3 demonstrated that performing an unrelated action did not. A unique but unrelated action was not memory
efficient. 相似文献
183.
In modern digital applications, users often interact with virtual representations of themselves or others, called avatars. We examined how these avatars and their perspectives influence stimulus–response compatibility in a Simon task. Participants responded to light/dark blue stimuli with left/right key presses in the presence of a task-irrelevant avatar. Changes in stimulus–response compatibility were used to quantify changes in the mental representation of the task and perspective taking toward this avatar. Experiments 1 and 2 showed that perspective taking for an avatar occurred in orthogonal stimulus–response mappings, causing a compatibility effect from the avatar’s point of view. In the following two experiments we introduced a larger variety of angular disparities between the participant and avatar. In Experiment 3, the Simon effect with lateralized stimulus positions remained largely unaffected by the avatar, pointing toward an absence of perspective taking. In Experiment 4, after avatar hand movements were added in order to strengthen the participants’ sense of agency over the avatar, a spatial compatibility effect from the avatar’s perspective was observed again, and hints of the selective use of perspective taking on a trial-by-trial basis were found. Overall, the results indicate that users can incorporate the perspective of an avatar into their mental representation of a situation, even when this perspective is unnecessary to complete a task, but that certain contextual requirements have to be met. 相似文献
184.
Body-image disturbances and low self-esteem have been implicated in the pathogenesis of eating disorders. This study investigated self-perception of body and personality among adolescent ballet dancers in a cross-sectional survey. Two questionnaires assessing "my body right now" and "my personality right now," using semantic differentials were completed by 90 ballet school students and 156 controls. Adolescent female dancers (ages 13 to 17 years) scored higher than age-matched controls and 11- to 12-yr. old peers on Undesirability and Sensitivity for personality and Unattractiveness for body. For both subscales of personality, differences were also found between male and female dancers; female ballet students scored higher. Within the control group a difference could be found only for Sensitivity on which girls scored higher than boys. Male dancers did not differ from controls except for a lower score on the Body mass measure. Adolescent female dancers showed a distinct answering profile for 7 of 16 semantic differentials in each questionnaire implicating less favorable body image and self-esteem. Interventions focused particularly on enhancing self-esteem may be useful in the prevention of psychopathology in adolescent ballet dancers. 相似文献
185.
Castiello U 《Perception & psychophysics》2001,63(6):1014-1025
This article includes two experiments aimed at investigating how two-dimensional (2-D) and three-dimensional (3-D) distractors affect the kinematics of prehension and aiming movements in order to understand the attentional processes involved in visuomotor control. In Experiment 1, subjects grasped large targets in the presence of both large and small 3-D distractors and their corresponding 2-D photographs. The distractors appeared for either 10 sec or appeared simultaneously with the target presentation. It was found that reach and grasp kinematics were influenced primarily by the small, suddenly appearing 3-D distractors. In Experiment 2, the purpose was to examine the conclusion that competition between objects (target and distractor) is related to the behavioral goal of the task. Experiment 2 is a replication of Experiment 1, with the exception that pointing movements were made instead of grasping movements. Results show that both 3-D and 2-D distractors interfered with pointing kinematics, supporting the hypothesis that attentional mechanisms are related to the goal of the task. 相似文献
186.
Smith CU 《Brain and cognition》2001,46(3):364-372
J. C. Eccles (1903-1997) had a highly distinguished career in neurophysiology, being awarded the Nobel Prize for Medicine or Physiology in 1963. This paper sets him within the Cartesian tradition of British neurophysiology initiated by Thomas Henry Huxley in the mid-19th century. It shows how the mind-brain problematique of the Cartesian tradition troubled him throughout his career, leading him finally to a solution in terms of quantum microphysics and microphysiology. This position, which has subsequently become fashionable, is discussed and shown (at least in the form Eccles espoused) to provide no solution to the problem posed by Descartes in the early 17th century. 相似文献
187.
L. R. James, R. G. Demaree, and G. Wolf (1984) introduced rWG(J) to estimate interrater agreement for a group. This index is calculated by comparing an observed group variance with an expected random variance. As researchers have gained experience using this index, several questions have arisen. What are the consequences of replacing values beyond the unit interval by 0? What is the dependence of rWG(J) on the group size? The authors' simulations show that a positive bias is caused by the truncation, but for large population values of rWG(J) it is negligible. Also, in this case, the group size has no effect on the expected value of rWG(J). For inference on rWG(J), researchers can exploit the availability of computers to simulate data from the hypothesized distribution and then compare the simulation results for rWG(J) with the actual values. In addition, it is shown how the bootstrap method can be used for comparing the indices of 2 groups. 相似文献
188.
Treasure JL Katzman M Schmidt U Troop N Todd G de Silva P 《Behaviour research and therapy》1999,37(5):405-418
Despite the major advances in the development of treatments for bulimia nervosa, drop-outs and a lack of engagement in treatment, continue to be problems. Recent studies suggest that the transtheoretical model of change may be applicable to bulimia nervosa. The aim of this study was to examine the roles of readiness to change and therapeutic alliance in determining engagement and outcome in the first phase of treatment. One hundred and twenty five consecutive female patients meeting DSM-IV criteria for bulimia nervosa took part in a randomised controlled treatment trial. The first phase of the sequential treatment compared four sessions of either cognitive behavioural therapy (CBT) or motivational enhancement therapy (MET) in engaging patients in treatment and reducing symptoms. Patients in the action stage showed greater improvement in symptoms of binge eating than did patients in the contemplation stage. Higher pretreatment scores on action were also related to the development of a better therapeutic alliance (as perceived by patients) after four weeks. However, pretreatment stage of change did not predict who dropped out of treatment. There were no differences between MET and CBT in terms of reducing bulimic symptoms or in terms of developing a therapeutic alliance or increasing readiness to change. The results suggest that the transtheoretical model of change may have some validity in the treatment of bulimia nervosa although current measures of readiness to change may require modification. Overall, readiness to change is more strongly related to improvement and the development of a therapeutic alliance than the specific type of treatment. 相似文献
189.
Zusammenfassung. Das hier vorgestellte Modell lernt graduell, Planungsaufgaben aus der Klasse der Maschinenbelegungsprobleme (job-shop-scheduling problems) zu lösen. Mit Hilfe des Chunking-Mechanismus von Soar wird episodisches Wissen über die Belegungsreihenfolge von Aufträgen auf Maschinen memoriert. Bei der Entwicklung des Modells wurden zahlreiche qualitative (z. B. Transfereffekte) und quantitative Befunde (z. B. Bearbeitungszeiten) aus einer früheren empirischen Untersuchung berücksichtigt. In einer Validierungsstudie wurden dieselben Aufgaben von 14 Probanden und dem Modell bearbeitet. Die Passung von Simulationsdaten und empirischen Ergebnissen fiel insgesamt gut aus. Allerdings löst das Modell die Aufgaben schneller und zeigt auch einen etwas besseren Lernverlauf als die Probanden. Das Modell liefert eine Erklärung für das Rauschen, das typischerweise bei Bearbeitungszeiten zu beobachten ist: es handelt sich um erworbenes Wissen, das mehr oder weniger gut und auch unterschiedlich häufig auf neue Situationen übertragen wird. Der Lernverlauf der Probanden entspricht nur für aggregierte Daten einer Potenzfunktion (power law). Der vorgestellte Mechanismus zeigt, wie ein symbolisches Modell der Informationsverarbeitung graduelle Verhaltensänderungen generiert und wie der offensichtliche Erwerb allgemeiner Prozeduren ohne explizites Lernen von deklarativen Regeln erfolgen kann. Es wird nahegelegt, daß es sich hier um die Modellierung einer Form impliziten Lernens handelt. Summary. The model presented here gradually learns how to perform a job-shop scheduling task. It uses Soar's chunking mechanism to acquire episodic memories about the order to schedule jobs. The model was based on many qualitative (e.g., transfer effects) and quantitative (e.g., solution time) regularities found in previously collected data. The model was tested with new data where scheduling tasks were given to the model and to 14 subjects. The model generally fit these data with the restrictions that the model performs the task (in simulated time) faster than the subjects, and its performance improves somewhat more quickly than the subjects' performance. The model provides an explanation of the noise typically found in problem solving times - it is the result of learning actual pieces of knowledge that transfer more or less to new situations but rarely by an average amount. Only when the data are averaged (i.e., over subjects) does the smooth power law appear. This mechanism demonstrates how symbolic models can exhibit a gradual change in behavior and how the apparent acquisition of general procedures can be performed without resorting to explicit declarative rule generation. We suggest that this may represent a type of implicit learning. 相似文献
190.