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   21599篇
  免费   118篇
  2023年   11篇
  2022年   19篇
  2021年   24篇
  2020年   54篇
  2019年   53篇
  2018年   3532篇
  2017年   2859篇
  2016年   2315篇
  2015年   253篇
  2014年   142篇
  2013年   242篇
  2012年   668篇
  2011年   2452篇
  2010年   2566篇
  2009年   1529篇
  2008年   1770篇
  2007年   2212篇
  2006年   56篇
  2005年   241篇
  2004年   217篇
  2003年   140篇
  2002年   85篇
  2001年   43篇
  2000年   62篇
  1999年   21篇
  1998年   28篇
  1997年   21篇
  1996年   10篇
  1995年   2篇
  1994年   5篇
  1993年   5篇
  1992年   3篇
  1991年   4篇
  1990年   11篇
  1989年   2篇
  1988年   4篇
  1987年   2篇
  1986年   2篇
  1984年   2篇
  1983年   2篇
  1982年   4篇
  1981年   4篇
  1980年   5篇
  1979年   3篇
  1978年   3篇
  1976年   10篇
  1975年   2篇
  1974年   4篇
  1973年   3篇
  1966年   2篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
The first section of the paper establishes the minimal properties of so-called consequential implication and shows that they are satisfied by at least two different operators of decreasing strength (symbolized by \(\rightarrow \) and \(\Rightarrow \)). Only the former has been analyzed in recent literature, so the paper focuses essentially on the latter. Both operators may be axiomatized in systems which are shown to be translatable into standard systems of normal modal logic. The central result of the paper is that the minimal consequential system for \(\Rightarrow \), CI\(\Rightarrow \), is definitionally equivalent to the deontic system KD and is intertranslatable with the minimal consequential system for \(\rightarrow \), CI. The main drawback ot the weaker operator \(\Rightarrow \) is that it lacks unrestricted contraposition, but the final section of the paper argues that \(\Rightarrow \) has some properties which make it a valuable alternative to \(\rightarrow \), turning out especially plausible as a basis for the definition of operators representing synthetic (i.e. context-dependent) conditionals.  相似文献   
992.
We present some proof-theoretic results for the normal modal logic whose characteristic axiom is \(\mathord {\sim }\mathord {\Box }A\equiv \mathord {\Box }\mathord {\sim }A\). We present a sequent system for this logic and a hypersequent system for its first-order form and show that these are equivalent to Hilbert-style axiomatizations. We show that the question of validity for these logics reduces to that of classical tautologyhood and first-order logical truth, respectively. We close by proving equivalences with a Fitch-style proof system for revision theory.  相似文献   
993.
This paper studies the relationship between Argumentation Logic (AL), a recently defined logic based on the study of argumentation in AI, and classical Propositional Logic (PL). In particular, it shows that AL and PL are logically equivalent in that they have the same entailment relation from any given classically consistent theory. This equivalence follows from a correspondence between the non-acceptability of (arguments for) sentences in AL and Natural Deduction (ND) proofs of the complement of these sentences. The proof of this equivalence uses a restricted form of ND proofs, where hypotheses in the application of the Reductio of Absurdum inference rule are required to be “relevant” to the absurdity derived in the rule. The paper also discusses how the argumentative re-interpretation of PL could help control the application of ex-falso quodlibet in the presence of inconsistencies.  相似文献   
994.
Cerreia-Vioglio et al. (Econ Theory 48(2–3):341–375, 2011) have proposed a very general axiomatisation of preferences in the presence of ambiguity, viz. Monotonic Bernoullian Archimedean preference orderings. This paper investigates the problem of Arrovian aggregation of such preferences—and proves dictatorial impossibility results for both finite and infinite populations. Applications for the special case of aggregating expected-utility preferences are given. A novel proof methodology for special aggregation problems, based on model theory (in the sense of mathematical logic), is employed.  相似文献   
995.
A contraction-free and cut-free sequent calculus \(\mathsf {G3SDM}\) for semi-De Morgan algebras, and a structural-rule-free and single-succedent sequent calculus \(\mathsf {G3DM}\) for De Morgan algebras are developed. The cut rule is admissible in both sequent calculi. Both calculi enjoy the decidability and Craig interpolation. The sequent calculi are applied to prove some embedding theorems: \(\mathsf {G3DM}\) is embedded into \(\mathsf {G3SDM}\) via Gödel–Gentzen translation. \(\mathsf {G3DM}\) is embedded into a sequent calculus for classical propositional logic. \(\mathsf {G3SDM}\) is embedded into the sequent calculus \(\mathsf {G3ip}\) for intuitionistic propositional logic.  相似文献   
996.
997.
Mechanisms underlying significant associations between different types of prayer and depression are unknown. Based on the conceptualization of prayer as stress buffering coping style and the Response Style Theory, we proposed that rumination mediates the association of prayer types and stress with depression. This cross-sectional study (N?=?227 Christians, Mage 41.74, SD 14.82, age range 18–82 years, 76% female) used path modeling to test whether rumination mediated the associations between prayer types and prayer types by stress interactions with depression. Rumination fully mediated the associations of the colloquial and ritual prayer by stress interactions with depressive symptoms, while meditative and petitionary prayer was directly associated with depressive symptoms. Further, petitionary prayer and the ritual prayer by stress interaction were associated with more and not with less rumination and depressive symptoms, respectively. Summarized, first empirical evidence supports an integration of prayer, stress, and rumination into one model of depression. However, the exact nature of their interplay depends on the prayer type. If replicated, our findings allow the integration of prayer into cognitive-behavioral treatment of depression in religious and spiritual clients.  相似文献   
998.
The study aimed to assess the prevalence of cannabis and amphetamine use and socio-ecological proximal and distal factors among adolescents in six Pacific Island countries. We analyzed cross-sectional survey data from 9,849 adolescents (mean age 14.2 years, SD?=?1.2) from Cook Islands, Kiribati, Samoa, Solomon Islands, Tonga and Tuvalu that participated in the “Global School-Based Student Health Survey (GSHS)” in 2011–2013. The prevalence of past-month cannabis use was 15.5%, and lifetime amphetamine use was 14.5%, with the highest prevalence in Samoa, 37.1% and 34.6%, respectively. In adjusted mixed-effects logistic regression analysis male gender, personal attributes (anxiety, loneliness, current tobacco use, current alcohol use and school truancy) and environmental stressors (having been in a physical fight, been physically attacked, sustained an injury, hunger and being bullied) were associated with past-month cannabis and/or lifetime amphetamine use. Parental substance use was positively and parental involvement negatively associated with past-month cannabis and/or lifetime amphetamine use. Measures to prevent and control cannabis and amphetamine use in this adolescent population should include personal attributes, environmental stressors and parental support.  相似文献   
999.
This study investigated two primary research aims surrounding health anxiety: (a) to examine what differences exist in emotion regulation strategies of health anxious and non-health anxious populations and (b) to investigate what emotion regulation strategies predict health anxiety, before and after controlling for trait cognitive and somatic anxiety. A total of 95 participants of the general population completed a series of online questionnaires. A single factor between groups MANOVA revealed that a health anxious group scored significantly higher in several emotion regulation strategies: distraction, external attribution, emotion expression and acting out; anxiety-related variables: trait cognitive and somatic anxiety; and beliefs about the negative consequences of becoming ill. Hierarchical regressions showed that several emotion regulation strategies were significantly associated with higher levels of health anxiety, before: distraction, external attribution, capitalising, positive reappraisal and emotional expression; and after: external attribution and capitalising, the control of trait anxiety. Overall, the results demonstrated that (a) emotional intelligence and behavioural attempts to understand emotional experiences may be associated with specific health anxiety symptomology, while a lack of effective cognitive strategies and worry may be responsible for the associated trait anxiety dimensions.  相似文献   
1000.
In contrast to a growing body of literature examining the experiences and trends of those who leave their faith tradition—particularly among Christian denominations—relatively little is known about those who specifically disaffiliate from Mormonism, although some evidence suggests that former Mormons may be especially likely to embrace secularity or irreligion rather than other religious beliefs and practices. Pursuant to empirically investigating this reactionary dynamic, the current study compared the relative religiosity and secularity of an online sample of active Mormons (n?=?194) and former Mormons (n?=?109) using the Abbreviated Religiousness Measure (ARM), an updated questionnaire of multidimensional religiosity. Results supported the ARM’s improved psychometrics and its hypothesized three-factor structure with both subsamples. Additionally, multivariate and univariate results indicated that active and former Mormon participants from our sample, significantly polarized in their self-reported level of religious beliefs, rituals, and influence on daily behaviors, with active Mormon reporting high religiosity and former Mormons reporting low religiosity or high secularity. Although these results comport with reactionary deconversion dynamics found in other high cost religions, limits to generalizability are discussed. Reasons for and implications of this reactionary phenomenon are also posited.  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