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91.
The renewed commitment of African states to modernising agriculture has reignited longstanding debates about different models of agricultural commercialisation. Which forms of commercialisation models will reduce land dispossession and the impoverishment of smallholders, and transform smallholder agriculture and the wider economy? Of the three broad models of agriculture commercialisation in this debate – plantation, contract farming and medium-scale commercial farming – contract farming has been identified as central to the future of Africa’s commercial agriculture. This paper provides empirical evidence from Ghana on the impacts of these three models on land, labour/employment, livelihoods and local economic linkages. Our findings show that the plantation and the commercial farming areas have highly commercialised land relations, land scarcity and high land prices, compared to the outgrower area where traditional systems of accessing land still dominate, enabling families to produce their own food crops while also diversifying into wage labour and other activities. Food insecurity was highest in the plantation area followed by the commercial area, but lowest in the outgrower area. Here, semi-proletarianised seasonal workers combine self-provisioning from their own farms with wages, and this results in better livelihood outcomes than for permanent workers in plantations and commercial farms. Due to the processing units in the plantation and the outgrower models, they provided more employment. However, the casualisation of labour and gender discrimination in employment and access to land occur in all three cases. All three models generated strong economic linkages mainly because they combined attributes such as processing, provided markets for nearby farmers, induced state infrastructural development and diffused technology in competitive ways. The effects of the models on household and local development are coproduced by their interaction with pre-existing conditions and wider national economic structures.  相似文献   
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Abstract

We contribute to the debate on the spatial allocation of infrastructure investments by examining where these investments generate the highest economic return (‘spatial efficiency’), and identifying trade-offs when infrastructure coverage is made more equitable across regions (‘spatial equity’). We estimate models of firm location choice in Uganda, drawing on insights from the new economic geography literature. The main findings show that manufacturing firms gain from being in areas that offer a diverse mix of economic activities. Public infrastructure investments in other locations are likely to attract fewer private investors, and will pose a spatial efficiency–equity trade-off.  相似文献   
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Student engagement is an important contributor to school success, yet high school students routinely describe themselves as disengaged. Identifying factors that alter (increase) engagement is a key aspect of improving support for student achievement. This study investigated students’ perceptions of autonomy, teacher connection, and academic competence as predictors of changes in student engagement within the classroom from the start to the end of a course. Participants were 578 (58% female) diverse (67.8% White, 25.2% African American, 5.1% Hispanic, 1.2% Asian American) high school students from 34 classrooms who provided questionnaire data both at the start and the end of a single course. Novel results from a cross-lagged model demonstrated that students who perceived their classrooms as allowing and encouraging their own autonomy in the first few weeks increased their engagement throughout the course, rather than the typical decline in engagement that was demonstrated by students in other classrooms. This finding is unique in that it extended to both students’ perceptions of engagement and observations of student engagement, suggesting a fairly robust pattern. The pertinence of this finding to adolescent developmental needs and its relationship to educational practice is discussed.  相似文献   
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The causal factors associated with increases in depressive symptoms among adolescent girls remain an area of theoretical debate, and the limited research considering a hormonal influence has provided mixed results. The goal of the present study was to test a set of longitudinal associations, that, if found, would provide support for a hormonal contribution to these changes. Specifically, this study tested the hypotheses that changes in depressive symptoms among adolescent girls would be associated with phase-specific symptoms of the menstrual cycle during early adulthood; that these associations would differ across three phases of the menstrual cycle; and that the pattern of associations would differ for changes in depressive symptoms during early- and late-adolescence. The sample consisted of 47 women with longitudinal data from 12 to 21 years old (approximately 91% European Canadian, 4% Middle Eastern Canadian, 2% Haitian Canadian, and 2% Asian Canadian). Consistent with expectations, results showed that early-adolescent increases in depressive symptoms were negatively associated with menstrual-phase negative affect, and positively associated with mid-cycle negative affect, but not associated with premenstrual negative affect; whereas late-adolescent change in depressive symptoms was only associated with depressive symptoms at 20-21 years. Thus, early-adolescent changes in depressive symptoms are longitudinally associated with later mood change across the menstrual cycle, suggesting a common underlying cause, which is hypothesized to be hormonal. Moreover, results suggest that, with respect to variables that are involved in affective development, important differences exist between early- and late-adolescence. The discussion considers menstrual-cycle-related symptoms (e.g., dysmenorrhea) during adolescence, and the need to study their effects on development. It is suggested that focused intervention and prevention efforts may be indicated to interrupt negative developmental outcomes.  相似文献   
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Victims of child abuse and neglect are at an increased risk of involvement with the juvenile justice and adult correctional systems. Yet, little is known about the continuation and trajectories of offending beyond initial contact with law enforcement. Neglect likely plays a critical role in continued offending as parental monitoring, parental rejection and family relationships are instrumental in explaining juvenile conduct problems. This study sought to determine whether neglect is associated with recidivism for moderate and high risk juvenile offenders in Washington State. Statewide risk assessments and administrative records for child welfare, juvenile justice, and adult corrections were analyzed. The sample was diverse (24 % female, 13 % African American, 8 % Hispanic, 5 % Native American) and included all moderate and high risk juvenile offenders screened by juvenile probation between 2004 and 2007 (n = 19,833). Official records from child protection were used to identify juvenile offenders with a history of child neglect and to identify juvenile offenders with an ongoing case of neglect. Event history models were developed to estimate the risk of subsequent offending. Adolescents with an ongoing case neglect were significantly more likely to continue offending as compared with youth with no official history of neglect. These findings remain even after controlling for a wide range of family, peer, academic, mental health, and substance abuse covariates. Interrupting trajectories of offending is a primary focus of juvenile justice. The findings of the current study indicate that ongoing dependency issues play a critical role in explaining the outcomes achieved for adolescents in juvenile justice settings. The implications for improved collaboration between child welfare and juvenile justice are discussed.  相似文献   
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In this introduction, we review the literature on intellectual property rights and access to medicines, identifying two distinct generations of research. The first generation analyzes the origins of new intellectual property rules, in particular the World Trade Organization’s Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS), and the significance of TRIPS to developing countries. The second generation examines national-level experiences, as countries adjust their laws and practices to conform to TRIPS. Based on the insights provided by the articles in the special issue, we contribute to the second generation by considering a pair of overarching sets of issues. First, we highlight the domestic political challenges that affect how countries go about implementing their new obligations under TRIPS. We argue that alliances and coalitions are necessary to underpin the use of policy instruments designed to conform to TRIPS while taking into account local conditions and needs, and we present insights that allow us to understand why alliances and coalitions are difficult to construct and sustain in this area. Second, we explain why policies that many countries adopt in response to TRIPS often do not generate their desired or intended outcomes. In the last section of the introduction, we review the articles that appear in this special issue.  相似文献   
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