全文获取类型
收费全文 | 5015篇 |
免费 | 111篇 |
专业分类
各国政治 | 236篇 |
工人农民 | 151篇 |
世界政治 | 236篇 |
外交国际关系 | 157篇 |
法律 | 3681篇 |
中国政治 | 26篇 |
政治理论 | 592篇 |
综合类 | 47篇 |
出版年
2020年 | 68篇 |
2019年 | 71篇 |
2018年 | 101篇 |
2017年 | 109篇 |
2016年 | 123篇 |
2015年 | 56篇 |
2014年 | 88篇 |
2013年 | 444篇 |
2012年 | 120篇 |
2011年 | 179篇 |
2010年 | 112篇 |
2009年 | 100篇 |
2008年 | 152篇 |
2007年 | 159篇 |
2006年 | 142篇 |
2005年 | 125篇 |
2004年 | 160篇 |
2003年 | 152篇 |
2002年 | 137篇 |
2001年 | 203篇 |
2000年 | 171篇 |
1999年 | 140篇 |
1998年 | 36篇 |
1996年 | 33篇 |
1993年 | 39篇 |
1992年 | 87篇 |
1991年 | 112篇 |
1990年 | 118篇 |
1989年 | 119篇 |
1988年 | 128篇 |
1987年 | 110篇 |
1986年 | 104篇 |
1985年 | 99篇 |
1984年 | 85篇 |
1983年 | 72篇 |
1982年 | 36篇 |
1981年 | 37篇 |
1979年 | 49篇 |
1978年 | 52篇 |
1977年 | 37篇 |
1976年 | 32篇 |
1975年 | 35篇 |
1974年 | 44篇 |
1973年 | 46篇 |
1972年 | 43篇 |
1971年 | 52篇 |
1970年 | 54篇 |
1969年 | 40篇 |
1968年 | 42篇 |
1967年 | 30篇 |
排序方式: 共有5126条查询结果,搜索用时 15 毫秒
141.
142.
143.
This study seeks to explain why U.S. local governments utilize environmental sustainability to promote economic development. Economic development and environmental protection need not be competing objectives, but rather, environmental protection can enhance local economic competitiveness. Using data from the ICMA Economic Development Survey, this study tests an empirical model that includes state sustainability initiatives, participation in climate protection networks, and political attitudes toward economic development as predictors of local policy decisions. The findings reinforce a multi-level governance perspective on explaining the balance cities seek to achieve between environmental protection and economic growth. 相似文献
144.
145.
146.
Terezie Cernosek B.S. Kevin E. Eckert M.Sc. David O. Carter Ph.D. Katelynn A. Perrault Ph.D. 《Journal of forensic sciences》2020,65(1):134-143
Volatile organic compounds (VOCs) are by-products of cadaveric decomposition and are responsible for the odor associated with decomposing remains. The direct link between VOC production and individual postmortem microbes has not been well characterized experimentally. The purpose of this study was to profile VOCs released from three postmortem bacterial isolates (Bacillus subtilis, Ignatzschineria indica, I. ureiclastica) using solid-phase microextraction arrow (SPME Arrow) and gas chromatography–mass spectrometry (GC-MS). Species were inoculated in headspace vials on Standard Nutrient Agar and monitored over 5 days at 24°C. Each species exhibited a different VOC profile that included common decomposition VOCs. VOCs exhibited upward or downward temporal trends over time. Ignatzschineria indica produced a large amount of dimethyldisulfide. Other compounds of interest included alcohols, aldehydes, aromatics, and ketones. This provides foundational data to link decomposition odor with specific postmortem microbes to improve understanding of underlying mechanisms for decomposition VOC production. 相似文献
147.
Levey Emma K. V. Garandeau Claire F. Meeus Wim Branje Susan 《Journal of youth and adolescence》2019,48(6):1068-1081
Journal of Youth and Adolescence - Adolescence tends to be characterized by a temporary peak in delinquent behavior, and friends in particular play a key role in the initiation and the development... 相似文献
148.
149.
Anthony L. Burrow Amanda C. O’Dell Patrick L. Hill 《Journal of youth and adolescence》2010,39(11):1265-1273
While having a purpose in life has been theorized as a developmental asset, the extent to which adolescents cultivate a meaningful
sense of direction is not well understood. In the present study, cluster analysis was used to classify adolescents by levels
of purpose exploration and commitment. The sample (N = 318; 55% female) consisted of youth aged 14–18 and was predominantly White/non-Hispanic (76.3%). Results supported four
meaningful yet distinguishable profiles of youth purpose that are largely consistent with theories on identity formation:
Achieved, Foreclosed, Uncommitted, and Diffused. Hypothesized linkages with affect and hope were established across the profiles
such that positive emotions and goal-directed thinking were most apparent among Achieved and Foreclosed youth and least apparent
among Diffused and Uncommitted youth. Overall, findings demonstrate the inherent complexity in adolescents’ engagement with
purpose and suggest a correspondence between stronger commitments to purpose and youths’ sense of personal agency and well-being. 相似文献
150.
Christopher C. Weiss Brian V. Carolan E. Christine Baker-Smith 《Journal of youth and adolescence》2010,39(2):163-176
In an effort to increase both adolescents’ engagement with school and academic achievement, school districts across the United
States have created small high schools. However, despite the widespread adoption of size reduction reforms, relatively little
is known about the relationship between size, engagement and outcomes in high school. In response, this article employs a
composite measure of engagement that combines organizational, sociological, and psychological theories. We use this composite
measure with the most recent nationally-representative dataset of tenth graders, Educational Longitudinal Study: 2002, (N = 10,946, 46% female) to better assess a generalizable relationship among school engagement, mathematics achievement and
school size with specific focus on cohort size. Findings confirm these measures to be highly related to student engagement.
Furthermore, results derived from multilevel regression analysis indicate that, as with school size, moderately sized cohorts
or grade-level groups provide the greatest engagement advantage for all students and that there are potentially harmful changes
when cohorts grow beyond 400 students. However, it is important to note that each group size affects different students differently,
eliminating the ability to prescribe an ideal cohort or school size. 相似文献