全文获取类型
收费全文 | 10838篇 |
免费 | 318篇 |
国内免费 | 2篇 |
专业分类
11158篇 |
出版年
2020年 | 102篇 |
2019年 | 134篇 |
2018年 | 150篇 |
2017年 | 176篇 |
2016年 | 220篇 |
2015年 | 162篇 |
2014年 | 197篇 |
2013年 | 1128篇 |
2012年 | 346篇 |
2011年 | 388篇 |
2010年 | 274篇 |
2009年 | 263篇 |
2008年 | 366篇 |
2007年 | 405篇 |
2006年 | 401篇 |
2005年 | 351篇 |
2004年 | 323篇 |
2003年 | 348篇 |
2002年 | 343篇 |
2001年 | 153篇 |
2000年 | 177篇 |
1999年 | 156篇 |
1998年 | 177篇 |
1997年 | 158篇 |
1996年 | 164篇 |
1995年 | 154篇 |
1994年 | 156篇 |
1993年 | 129篇 |
1992年 | 141篇 |
1991年 | 134篇 |
1990年 | 116篇 |
1989年 | 119篇 |
1988年 | 117篇 |
1987年 | 125篇 |
1986年 | 127篇 |
1985年 | 139篇 |
1984年 | 144篇 |
1983年 | 154篇 |
1982年 | 173篇 |
1981年 | 161篇 |
1980年 | 150篇 |
1979年 | 124篇 |
1978年 | 164篇 |
1977年 | 153篇 |
1976年 | 144篇 |
1975年 | 141篇 |
1974年 | 143篇 |
1973年 | 135篇 |
1972年 | 105篇 |
1968年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
891.
892.
The present study is the first long-term longitudinal examination of the etiology of individual differences in language from early childhood through to adolescence. We applied a multivariate latent factor genetic model to longitudinal data from the Twins Early Development Study in order to (a) compare the magnitude of genetic and environmental influences on language skills in early childhood (2, 3 and 4 years), middle childhood (7, 9 and 10 years), and early adolescence (12 years); and (b) determine to what extent the same genetic and environmental factors underlie variation in language skills at these three stages of language development. We found that while shared environmental influences appear to be dominant (latent factor c2 = .74) in early language, with a smaller though significant role for genetic factors (latent factor a2 = .24), the pattern is reversed by middle childhood such that genetic influences are substantially more important (latent factor a2 = .57-.63 at 7, 9 and 10 years and .47-.57 at 12 years) and shared environmental influences less so (latent factor c2 = .31-.37 at 7, 9 and 10 years and .31-.32 at 12 years). The increase in the heritability of language skills between early and middle childhood appears to be due to new genetic factors that come into play at that transition. In contrast, genetic factors remain stable from middle childhood through to early adolescence, and account for the phenotypic continuity in language skills across these two stages. 相似文献
893.
Robert G. Sposato Kathrin Röderer Renate Cervinka 《Transportation Research Part F: Traffic Psychology and Behaviour》2012,15(5):581-587
Existing research on commuting stress has shown that it is affected by variables such as control, predictability, the duration of the commute and impedance. The present study investigates the impact of several factors on the stress that commuters experience and clarifies possible relations between variables. For the purpose of this study, an online questionnaire was completed by 363 commuters of the Vienna region. The relative strength of the relationship between predictors and commuting stress was determined by multiple regression analysis. Results suggest that control is the most powerful predictor of commuting stress, followed by the duration of the commute, predictability and impedance. Control significantly interacts with the duration of the commute and predictability. Based on these findings a research model is proposed, clearly depicting the moderating impact of the duration of the commute and incorporating a clear distinction between predictability and control. 相似文献
894.
Jo?lle Carpentier Geneviève A. Mageau Robert J. Vallerand 《Journal of Happiness Studies》2012,13(3):501-518
Research shows that harmonious and obsessive passion are positively and negatively linked to well-being respectively (e.g., Vallerand et al. in J Personal 75:505?C534, 2007; Psychol Sport Exerc 9:373?C392, 2008). The present study investigated the psychological mechanisms underlying the different impact of the two types of passion on well-being. A theoretical model involving passion, ruminations, flow experiences, and well-being was tested. Results showed that the more people have a harmonious passion, the more they tend to experience flow in their favorite activity, which in turn predicts higher well-being. Obsessive passion did not seem to be systematically linked to flow in the favorite activity. In contrast, the more people have an obsessive passion, the more they tend to ruminate about their passionate activity while engaging in another activity, which did not seem to be systematically the case for people with a harmonious passion. These ruminations are negatively related to flow experiences in the other activity, which are positively associated with well-being. Flow and ruminations thus seem to contribute to the understanding of the link between passion and well-being. 相似文献
895.
Communal predators may often need to make especially intricate foraging decisions, as a predator's success may depend on the actions of its neighbours. Here,we consider the decisions made by Portia africana, a jumping spider (Salticidae) that preys on other spiders, including Oecobius amboseli (Oecobiidae), a small prey spider that lives under small sheets of silk (nests) on the walls of buildings. P. africana juveniles settle near oecobiid nests and then ambush oecobiids as they leave or enter the nest. Two or more P. africana juveniles sometimes settle at the same nest and, when an oecobiid is captured, the P. africana juveniles may share the meal. We investigated the joining decisions made by na?ve P. africana juveniles. Experiments were based on using lures (dead spiders positioned in lifelike posture) arranged in a series of 17 different scenes defined by the presence/absence of a nest, the lure types present and the configuration of the lures and the nest. Our findings imply that P. africana juveniles make remarkably precise predatory decisions, with the variables that matter including whether a nest is present, the identity of spiders inside and outside a nest and how spiders are positioned relative to each other and the nest. 相似文献
896.
Robert J. Schinke Justin Bonhomme Kerry R. McGannon Jessica Cummings 《Psychology of sport and exercise》2012,13(6):830-839
ObjectivesThe Super Six World Boxing Classic was conceived by Showtime Sports to feature the best six professional boxers in the super middleweight division (168 pounds) throughout a modified round robin tournament. The objective was to explore the adaptation and mal-adaptation processes of the tournament's original six tournament participants over time.DesignMedia data in the form of documentary episodes (n = 12 episodes, ~30 min each from the foregoing source were transcribed verbatim. Data included athletes' responses prior to their first bout and as each progressed or was eliminated. Boxers' post-bout explanations were also included.MethodThe original six contestants (mean age = 28.8 years at tournament start) from the tournament, with a record of 157 wins and 4 losses, were included within the project. Data were analyzed via thematic analysis (see Braun & Clarke, 2006).ResultsThe following themes were identified: (a) pre-conditions: moving into the tournament (subthemes: positive anticipation, uncertainty), (b) outcomes: moving through the tournament (subthemes: tournament progression, tournament regressions), and (c) consequences: moving out of the tournament (sub-themes: responses of the defeated, the king's adaptation).ConclusionsThis study highlights the adaptation processes of the six tournament contestants, demonstrating how one athlete adapted successfully and became champion through personal focus. The remaining athletes lost at least once, with pre-bout adaptation processes suggesting performance regression. These findings add to the adaptation literature, further contextualizing how adaptation meanings change and unfold over time. 相似文献
897.
898.
A new method is proposed for controlling mosquito-borne diseases. In particular, instead of trying to kill mosquitoes, we suggest provisioning them with food from artificial feeders. Because mosquito populations are frequently limited by ecological factors other than blood meals, such as the availability of egg-laying sites, feeding mosquitoes would not necessarily increase the total number of mosquitoes, but could reduce the number of human-drawn mosquito meals. Like mosquito traps, feeders could divert biting mosquitoes away from people by means of lures, but, after diversion, prevent subsequent human bites by satiating the mosquitoes instead of killing them. Mosquito feeders might reduce the problem of the evolution of resistance to control: in an ecology with mosquito feeders, which provide safe and abundant calories for adult female mosquitoes, there could be selection for preferring (rather than avoiding) feeders, which could eventually lead to a population of feeder-preferring mosquitoes. Artificial feeders also offer the chance to introduce novel elements into the mosquito diet, such as anti- malarial or other anti-parasitic agents. Feeders might directly reduce human bites and harnesses the power of natural selection by selectively favoring feeder-preferring (rather than trap-resistant) mosquitoes. 相似文献
899.
Humans (Homo sapiens) and chimpanzees (Pan troglodytes) can extract socially-relevant information from the static, non-expressive faces of conspecifics. In humans, the face is a valid signal of both personality and health. Recent evidence shows that, like humans, chimpanzee faces also contain personality information, and that humans can accurately judge aspects of chimpanzee personality relating to extraversion from the face alone (Kramer, King, and Ward, 2011). These findings suggest the hypothesis that humans and chimpanzees share a system of personality and facial morphology for signaling socially-relevant traits from the face. We sought to test this hypothesis using a new group of chimpanzees. In two studies, we found that chimpanzee faces contained health information, as well as information of characteristics relating to extraversion, emotional stability, and agreeableness, using average judgments from pairs of individual photographs. In a third study, information relating to extraversion and health was also present in composite images of individual chimpanzees. We therefore replicate and extend previous findings using a new group of chimpanzees and demonstrate two methods for minimizing the variability associated with individual photographs. Our findings support the hypothesis that chimpanzees and humans share a personality signaling system. 相似文献
900.
The effects of two kinds of meditation (open presence and focused) on the facial and physiological aspects of the defensive response to an aversive startle stimulus were studied in a Buddhist monk with approximately 40 years of meditation experience. The participant was exposed to a 115-db, 100-ms acoustic startle stimulus under the 2 meditation conditions, a distraction condition (to control for cognitive and attentional load) and an unanticipated condition (startle presented without warning or instruction). A completely counterbalanced 24-trial, single-subject design was used, with each condition repeated 6 times. Most aspects of the participant's responses in the unanticipated condition did not differ from those of a comparison group of 12 age-matched male controls. Both kinds of meditation produced physiological and facial responses to the startle that were smaller than in the distraction condition. Within meditation conditions, open presence meditation produced smaller physiological and facial responses than focused meditation. These results from a single highly expert meditator indicate that these 2 kinds of meditation can differentially alter the magnitude of a primitive defensive response. 相似文献