全文获取类型
收费全文 | 9656篇 |
免费 | 271篇 |
国内免费 | 5篇 |
出版年
2023年 | 62篇 |
2022年 | 86篇 |
2021年 | 103篇 |
2020年 | 141篇 |
2019年 | 137篇 |
2018年 | 371篇 |
2017年 | 339篇 |
2016年 | 403篇 |
2015年 | 238篇 |
2014年 | 194篇 |
2013年 | 746篇 |
2012年 | 651篇 |
2011年 | 647篇 |
2010年 | 264篇 |
2009年 | 187篇 |
2008年 | 344篇 |
2007年 | 284篇 |
2006年 | 268篇 |
2005年 | 1504篇 |
2004年 | 767篇 |
2003年 | 562篇 |
2002年 | 257篇 |
2001年 | 83篇 |
2000年 | 85篇 |
1999年 | 67篇 |
1998年 | 30篇 |
1996年 | 24篇 |
1994年 | 23篇 |
1992年 | 54篇 |
1991年 | 58篇 |
1990年 | 78篇 |
1989年 | 65篇 |
1988年 | 51篇 |
1987年 | 57篇 |
1986年 | 44篇 |
1985年 | 40篇 |
1984年 | 41篇 |
1983年 | 31篇 |
1979年 | 44篇 |
1976年 | 23篇 |
1975年 | 35篇 |
1974年 | 42篇 |
1973年 | 38篇 |
1972年 | 34篇 |
1971年 | 35篇 |
1970年 | 27篇 |
1969年 | 28篇 |
1968年 | 27篇 |
1967年 | 25篇 |
1966年 | 24篇 |
排序方式: 共有9932条查询结果,搜索用时 15 毫秒
921.
The literature on quantum logic emphasizes that the algebraic structures involved with orthodox quantum mechanics are non
distributive. In this paper we develop a particular algebraic structure, the quasi-lattice (
\mathfrakI{\mathfrak{I}}-lattice), which can be modeled by an algebraic structure built in quasi-set theory
\mathfrakQ{\mathfrak{Q}} . This structure is non distributive and involve indiscernible elements. Thus we show that in taking into account indiscernibility
as a primitive concept, the quasi-lattice that ‘naturally’ arises is non distributive. 相似文献
922.
André Elias Mazawi 《Studies in Philosophy and Education》2011,30(2):169-183
The present paper offers a reflection on school textbooks produced and introduced by the Palestinian Authority in the West
Bank and Gaza Strip from the year 2000 onward. The aim is to examine the debates over these textbooks, by situating them over
the backdrop of larger geopolitical dynamics and intra-Palestinian social and political struggles. 相似文献
923.
In this paper we study some questions concerning ?ukasiewicz implication algebras. In particular, we show that every subquasivariety of ?ukasiewicz implication algebras is, in fact, a variety. We also derive some characterizations of congruence permutable algebras. The starting point for these results is a representation of finite ?ukasiewicz implication algebras as upwardly-closed subsets in direct products of MV-chains. 相似文献
924.
Slioussar N 《Journal of psycholinguistic research》2011,40(4):291-306
In languages with flexible constituent order (so-called free word order languages), available orders are used to encode given/new distinctions; they therefore differ not only syntactically, but also in their
context requirements. In Experiment 1, using a self-paced reading task, we compared Russian S V IO DO (canonical), DO S V
IO and DO IO V S constructions in appropriate vs. inappropriate contexts (those that violated their context requirements).
The context factor was significant, while the syntax factor was not. The less pronounced context effect evidenced in previous
studies (e.g., Kaiser and Trueswell in Cognitioin 94:113–147, 2004) might be due to the use of shorter target sentences and less extensive contexts. We also demonstrated that the slow-down
starts at the first contextually inappropriate constituent, which shows that the information about context requirements is
taken into account immediately, but that it develops faster on preverbal subjects and postverbal indirect objects (occupying
their canonical positions) than on preverbal indirect objects (occupying a noncanonical position, or scrambled). In Experiment 2, these findings were replicated for IO S V DO and IO DO V S orders. S V IO DO orders with a continuation
were used to show that there is no additional effect of inappropriate context at the end of the sentence. 相似文献
925.
McDonald R Dodson MC Rosenfield D Jouriles EN 《Journal of abnormal child psychology》2011,39(7):1013-1023
This study examined whether Project Support, a parenting intervention shown to reduce child conduct problems, also exerts
positive effects on features of psychopathy in children. Participants were 66 families (mothers and children) recruited from
domestic violence shelters who participated in a randomized controlled trial evaluating Project Support. Each family included
at least one child between the ages of 4 and 9 who was exhibiting clinical levels of conduct problems. Families were randomly
assigned to the Project Support intervention condition or to an existing services comparison condition, and they were assessed
on 6 occasions over 20 months, following their departure from the shelter. Children in families in the Project Support condition,
compared with those in the comparison condition, exhibited greater reductions in features of psychopathy. Moreover, the changes
in features of psychopathy remained after accounting for changes in conduct problems. Project Support’s effects on features
of psychopathy were mediated by improvements in mothers’ harsh and inconsistent parenting. These findings on the effects of
an intervention on features of psychopathy are the first from a randomized controlled trial. They inform the debate about
whether features of psychopathy in children are responsive to intervention, and hold important implications for clinical practice. 相似文献
926.
The dramatic increase in diagnostic rates of bipolar disorder in children and adolescents in the USA has led to an intense
interest in the phenomenology of the disorder. Here we present data from a newly-developed instrument to assess episodic mania-like
symptoms in youth in a large population-based sample (N = 5326) using parent- and self-report. We found that a substantial proportion of children screened positive for having episodes
of “going high” and were at an increased risk for morbidity and impairment. Using factor analysis, we identified that episodic
mania-like symptoms comprised two dimensions: An under-controlled dimension that was associated with significant impairment, and a low-risk exuberant dimension. Using latent class analysis, we identified a small group of children scoring high on a range of manic symptoms
and suffering from severe psychosocial impairment and morbidity. Our results carry implications for the nosology and psychosocial
impairment associated with episodic mood changes in young people. 相似文献
927.
Karin?S.?NijhofEmail author Ad?Vermulst Ron?H.?J.?Scholte Coleta?van?Dam Jan?Willem?Veerman Rutger?C.?M.?E.?Engels 《Journal of abnormal child psychology》2011,39(1):59-70
The present study examined whether a sample of 214 (52.8% male, M age = 15.76, SD = 1.29) institutionalized adolescents could be classified into subgroups based on psychopathic traits. Confirmatory Factor
Analyses revealed a relationship between the subscales of the Youth Psychopathic traits Inventory (YPI) and the three latent
constructs of the original model on which it is based. Latent Class Analyses showed that adolescents showing psychopathic
traits could be classified into three subgroups. The first group showed low scores on the grandiose/manipulative dimension,
the callous/unemotional dimension, and the impulsive/irresponsible dimension (normal group). The second group scored moderate
on the grandiose/manipulative dimension and the callous/unemotional dimension and high on the impulsive/irresponsible dimension
(impulsive, non-psychopathic-like group). The third group scored high on all three dimensions (psychopathy-like group). The
findings revealed that the impulsive, non-psychopathic like group scored significantly higher on internalizing problem behavior
compared to the normal group, while the psychopathy-like and the impulsive, non-psychopathic-like group both scored higher
on externalizing problem behavior compared to the normal group. Based on a self-report delinquency measure, it appeared that
the psychopathy-like group had the highest delinquency rates, except for vandalism. Both the impulsive and psychopathy-like
group had the highest scores on the use of soft drugs. 相似文献
928.
This study examined the extent to which sixth grade peer status could predict anxiety and/or depression in 5,242 women and
5,004 men who were born in 1953 and whose hospital records were followed up from 1973–2003. The data used was the Stockholm
Birth Cohort Study. While no association could be established for men, results indicated that women who held low peer status
positions in childhood were at a considerably higher risk of anxiety and/or depression later in life compared to women in
average status positions. Women who held popular positions during childhood did not differ significantly from their average
counterparts. These findings persisted after adjusting for family- and child-related problem-load, perceived security at school,
family constellation, socioeconomic status as well as the child’s cognitive ability, ninth grade school marks and continuance
to upper secondary school. 相似文献
929.
Conflicting findings exist regarding (1) whether anxiety sensitivity (AS) is a construct distinct from anxiety in children
and (2) the specific nature of the role of AS in child anxiety. This study uses meta-analytic techniques to (1) determine
whether youth (ages 6–18 years) have been reported to experience AS, (2) examine whether AS differentiates anxiety disordered
youth from youth without diagnoses, and (3) ascertain whether AS distinguishes youth with panic disorder from those with other
anxiety disorders. The weighted mean effect size analyses included 15 studies and 6,579 participants. Results suggested positive
correlational relationships between AS and anxiety for children (r = 0.26) and adolescents (r = 0.36) and higher levels of AS for anxiety disordered youth than non-clinical youth (d = 0.64). Findings tentatively suggested higher levels of AS for youth with panic disorder than youth diagnosed with other
anxiety disorders. Implications and future directions in the research of child AS are discussed. 相似文献
930.