全文获取类型
收费全文 | 4209篇 |
免费 | 272篇 |
国内免费 | 2篇 |
出版年
2024年 | 10篇 |
2023年 | 69篇 |
2022年 | 63篇 |
2021年 | 95篇 |
2020年 | 159篇 |
2019年 | 139篇 |
2018年 | 201篇 |
2017年 | 229篇 |
2016年 | 194篇 |
2015年 | 126篇 |
2014年 | 157篇 |
2013年 | 546篇 |
2012年 | 315篇 |
2011年 | 311篇 |
2010年 | 208篇 |
2009年 | 126篇 |
2008年 | 278篇 |
2007年 | 199篇 |
2006年 | 212篇 |
2005年 | 120篇 |
2004年 | 101篇 |
2003年 | 76篇 |
2002年 | 67篇 |
2001年 | 33篇 |
2000年 | 58篇 |
1999年 | 33篇 |
1998年 | 16篇 |
1997年 | 21篇 |
1996年 | 20篇 |
1995年 | 17篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 19篇 |
1991年 | 21篇 |
1990年 | 31篇 |
1989年 | 21篇 |
1988年 | 17篇 |
1987年 | 20篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1972年 | 5篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有4483条查询结果,搜索用时 15 毫秒
221.
Male aggressiveness is a complex behavior influenced by a number of genetic and non-genetic factors. Traditionally, the contribution of each of these factors has been established from experiments using artificially selected strains for high/low aggressive phenotypes. However, little is known about the factors underlying aggressive behavior in natural populations. In this study, we assess the influence of genetic background vs. postnatal maternal environment using a set of cross-fostering experiments between two wild-derived inbred strains, displaying high (STRA, derived from Mus musculus domesticus) and low (BUSNA, derived from Mus musculus musculus) levels of aggressiveness. The role of maternal environment was tested in males with the same genetic background (i.e. strain origin) reared under three different conditions: unfostered (weaned by mother), infostered (weaned by an unfamiliar dam from the same strain), and cross-fostered (weaned by a dam from a different strain). All males were tested against non-aggressive opponents from the A/J inbred strain. Resource-holding potential was assessed through body weight gains and territory ownership. The STRA males were shown to be aggressive in both neutral cage and resident-intruder tests. On the contrary, the BUSNA males were less aggressive in all tests. We did not find a significant effect of postnatal maternal environment; however, we detected significant maternal effect on body weight with differences between the strains, fostering type and interactions between these factors. We conclude that the aggressiveness preserved in the two strains has significant genetic component whose genetic basis can be dissected by quantitative trait loci analysis. 相似文献
222.
223.
Canals J Hernández-Martínez C Fernández-Ballart JD 《Infant behavior & development》2011,34(1):152-160
The aim of this study was to analyze the extent to which the relations and the stability of the neonatal behaviour and the infant behaviour at both 4 and 12 months could be used to predict the infant temperament at 6 years. Seventy-two full-term, normal-weight, healthy children were followed from 3 days postpartum to 6 years. Neonatal behaviour at 3 and 30 days was assessed using the Neonatal Behaviour Assessment Scale (NBAS), behaviour at 4 and 12 months was assessed using the Infant Behaviour Record (IBR) from the Bayley Scales for Infant Development (BSID) and temperament at 6 years was assessed using the Dimensions of Temperament Survey-Revised (DOTS-R). Negative and positive affectivity and attention were the factors extracted from the behaviours of the IBR. Our results showed a low/moderate correlation between neonatal behaviour on the one hand and behaviour at 4 and 12 months and temperament at 6 years on the other hand. The motor performance, orientation and ANS stability of the neonate at 3 and 30 days were predictors of positive and negative affectivity at 4 months. State regulation and ANS stability at 3 days were predictors of negative affectivity and attention respectively at 12 months. Negative affectivity at 12 months and endurance at 30 days were predictors of general activity and persistence/attention at 6 years. Also, an inverse relation was found between state regulation at 30 days and general activity at 6 years, and a positive relation was found between attention at 4 months and persistence/attention at 6 years. We conclude that neonatal behaviour and behaviour in the first year of life are good predictors of temperament at 6 years and that early negative affectivity has an important role on infant temperament development. 相似文献
224.
Bigongiari A de Andrade e Souza F Franciulli PM Neto Sel R Araujo RC Mochizuki L 《Human movement science》2011,30(3):648-657
The aim of this study was to examine postural control in children with cerebral palsy performing a bilateral shoulder flexion to grasp a ball from a sitting posture. The participants were 12 typically developing children (control) without cerebral palsy and 12 children with cerebral palsy (CP). We analyzed the effect of ball mass (1 kg and 0.18 kg), postural adjustment (anticipatory, APA, and compensatory, CPA), and groups (control and CP) on the electrical activity of shoulder and trunk muscles with surface electromyography (EMG). Greater mean iEMG was seen in CPA, with heavy ball, and for posterior trunk muscles (p < .05). The children with CP presented the highest EMG and level of co-activation (p < .05). Linear regression indicated a positive relationship between EMG and aging for the control group, whereas that relationship was negative for participants with CP. We suggest that the main postural control strategy in children is based on corrections after the beginning of the movement. The linear relationship between EMG and aging suggests that postural control development is affected by central nervous disease which may lead to an increase in muscle co-activation. 相似文献
225.
The results of this study are part of an investigation to determine whether the cognitive-emotional process of emotional recognition is deficient as a function of the clinical condition and alexithymia in subjects with somatization. This investigation applied the self-assessment of emotion and used a procedure that minimizes the use of verbal skills and verbal comprehension. The specific goal of this study was to verify whether there were differences in the covariation between alexithymia and self-evaluation of the emotional reaction in clinical and nonclinical subjects. The results of this study highlight the significant differences between clinical and control subjects. There were inverse significant correlations with the affective valence in clinical subjects, whereas in the ratings of the TAS-20 in control subjects, there were direct correlations with activation. In the conclusions, we discuss whether the variability of the results of previous research of the relationship between alexithymia and emotional recognition is a characteristic feature of this relationship or an effect of the different sampling and procedures utilized. 相似文献
226.
The aim of this study was to evaluate a procedure to reveal the emergence of full naming in typically developing children. In Experiment 1, five 6-year-old children (a) learned tacts of pictures and the emergence of the selection of these pictures upon hearing their names was tested; and (b) the selection of other pictures was taught and the emergence of the tacts was tested. All children showed the emergence of picture selection and 3 children showed the emergence of the tacts. In Experiment 2a, the children's correct repetition of the names of 3 pictures was verified first, then the experimenter presented the pictures with their names without requiring any behavior other than attending. Finally, the emergence of picture selection and the tacts was tested. Experiment 2b replicated Experiment 2a with words that were easier to pronounce. Picture selection and the tacts emerged; this performance documented full naming for the first time with typically developing children. These procedures can be used to induce naming capacity in children who lack it; hence, they can be applied to teach children with learning delays. 相似文献
227.
This paper presents two experiments on nutrient-based flavor conditioning with rats as subjects and sucrose as the unconditioned stimulus (US). Experiment 1 was aimed at establishing an optimal control for conditioning, comparing simultaneous and serial presentations of a flavor and the US. The results showed that simultaneous, but not serial training, produced conditioning. Experiment 2 was designed to obtain evidence of summation as an index of both conditioned inhibition and predictive learning. Group Simultaneous received Pavlovian conditioned inhibition training during which flavor A was simultaneously paired with sucrose on excitatory trials (A+), and forming an unreinforced compound with flavor B on inhibitory trials (AB-). An independent excitor for the summation test was also trained by simultaneous pairings with sucrose (C+). In the control group (Blocked), the AB- trials were presented forming a block at the beginning of training to avoid a negative contingency-relationship with sucrose, and flavor A received serial rather than simultaneous pairing with sucrose (A --> +). On the summation test, only in group Simultaneous was consumption of the CB compound lower than that of flavor C alone, suggesting that, during training, flavor A activated an expectancy of the US occurrence. 相似文献
228.
Optimism has been classically considered a key trait in entrepreneurs' personality but it has been studied from a psychological point of view only in recent years. The main aim of this research is to study the relationship between dispositional optimism, pessimism and realism as a function of the tendency to create technology-based businesses. A sample of undergraduate students (n= 205) filled in an electronic questionnaire containing the Life Orientation Test-Revised after they were classified as potential technological entrepreneurs, potential general entrepreneurs and non-potential entrepreneurs. Our results show that technology-based entrepreneurs are more optimistic than non-potential entrepreneurs, whereas there were no statistical differences in pessimism and realism. The results are interpreted theoretically to define the potential entrepreneur and, from an applied perspective, to design training programmes to support future technological entrepreneurs. 相似文献
229.
This article reports on the diagnostic validity of the Dominic Interactive Assessment (DIA) in a sample of Spanish children exposed to intimate partner violence (IPV). The study participants included 55 children aged between 6 and 11 years whose mothers visited an IPV counselling centre. Psychopathology and functional impairment were used as the main criteria for assessing predictive and discriminative accuracy, as well as incremental validity, of DIA. The results indicate that DIA permits obtaining useful information from children. This information improves the prediction and validity of the process of clinical assessment of children exposed to IPV. Children's self-reports could prove effective in identifying cases in this high-risk population when developmentally adequate instruments and functional criteria are used. 相似文献
230.
Although homework completion is said to be rather important to achievement, nowadays there is a growing concern of educators about the increasing number of students who do not engage properly on doing the homework tasks and the subsequent impact on school failure rates. Focusing on English as a Foreign Language (EFL) and using a sample of 591 Portuguese fifth and sixth graders, the present study analyses the role played by a number of homework variables on students' achievement (proximal and distal), and their mediating role on the use of self-regulated learning strategies and perceived self-efficacy in the domain. Data confirm the indirect effect of homework on school achievement, by means of the referred cognitive and motivational variables (use of self-regulated learning strategies and self-efficacy). These findings are further discussed in order to highlight the significant role homework completion can play on fighting school failure. 相似文献