全文获取类型
收费全文 | 6245篇 |
免费 | 149篇 |
专业分类
各国政治 | 272篇 |
工人农民 | 300篇 |
世界政治 | 491篇 |
外交国际关系 | 232篇 |
法律 | 3837篇 |
中国政治 | 55篇 |
政治理论 | 1186篇 |
综合类 | 21篇 |
出版年
2022年 | 32篇 |
2021年 | 40篇 |
2020年 | 78篇 |
2019年 | 110篇 |
2018年 | 144篇 |
2017年 | 133篇 |
2016年 | 141篇 |
2015年 | 80篇 |
2014年 | 129篇 |
2013年 | 663篇 |
2012年 | 154篇 |
2011年 | 167篇 |
2010年 | 135篇 |
2009年 | 152篇 |
2008年 | 184篇 |
2007年 | 178篇 |
2006年 | 158篇 |
2005年 | 143篇 |
2004年 | 176篇 |
2003年 | 139篇 |
2002年 | 110篇 |
2001年 | 319篇 |
2000年 | 287篇 |
1999年 | 205篇 |
1998年 | 89篇 |
1997年 | 89篇 |
1996年 | 60篇 |
1995年 | 61篇 |
1994年 | 59篇 |
1993年 | 49篇 |
1992年 | 132篇 |
1991年 | 151篇 |
1990年 | 144篇 |
1989年 | 131篇 |
1988年 | 121篇 |
1987年 | 126篇 |
1986年 | 102篇 |
1985年 | 103篇 |
1984年 | 101篇 |
1983年 | 88篇 |
1982年 | 62篇 |
1981年 | 74篇 |
1980年 | 38篇 |
1979年 | 77篇 |
1978年 | 44篇 |
1975年 | 42篇 |
1974年 | 50篇 |
1973年 | 54篇 |
1972年 | 40篇 |
1971年 | 34篇 |
排序方式: 共有6394条查询结果,搜索用时 15 毫秒
991.
Kristopher D. Wisniewski Ph.D. Nicholas Cooper M.Sc. Vivienne Heaton Ph.D. Colin Hope B.Sc.; M.Sc. Duncan Pirrie Ph.D. Andrew J. Mitten M.Geo. Jamie K. Pringle Ph.D. 《Journal of forensic sciences》2019,64(5):1530-1539
Police witness intelligence stated a murdered adult male “Fred” had been vertically buried in wooded hilly terrain 30 years ago in the Midlands, U.K. Conventional search methods were unsuccessful; therefore, the police requested a geophysical investigation to be undertaken to determine whether “Fred” could be detected. A multiphased geophysical approach was conducted, using bulk ground conductivity and metal detectors, then follow‐up magnetics and ground penetrating radar (GPR) survey profiles on electromagnetic (EM) anomalous areas. A tight grid pattern was used to account for the reduced target size. Relatively high‐resolution EM and GPR techniques were determined optimal for this terrain and sandy soil. Geophysical anomalies were identified and the most promising intrusively investigated, and this was found to be a large boulder and tree roots. Study implications suggest careful multiphase geophysical surveys are best practice and give confidence in cold case searches. This study yielded a no‐body result, effectively saving police time and costs from further investigations. 相似文献
992.
993.
Christina Mancini Amy K. Cook Jessica C. Smith Robyn McDougle 《Journal of school violence》2020,19(4):610-622
ABSTRACT Recently, states have enacted teacher-carry laws. While controversial, little scholarship has tapped public attitudes toward such reforms. Because public opinion shapes policy, the public is an important stakeholder in this debate. Thus, we investigated three questions. First, how supportive is the public of arming teachers? Second, what demographic and social divides exist, if any, for reform approval? Finally, do crime-related perceptions, concerning views about public safety, and criminogenic influences shape policy preferences? We test these questions using a 2018 poll of Virginia residents (N = 521). Overall, approval for teacher-carry is split. Crime-related perceptions mediate some of the initial social and demographic divides in opinion but other correlates, such as parental status, remain salient predictors of views. Implications are discussed. 相似文献
994.
995.
996.
997.
998.
Conventional models of bargaining and reassurance under incomplete information assume that actors' behavioral signals are objectively cooperative or noncooperative. Even if actors are uncertain of each other's preferences, they know what types of actions the other will view as cooperative. Yet on many real-world issues, cooperation is subjective, and what constitutes a cooperative action is conditional on the receiver's preferences. We present a formal model showing that in these cases, two-sided incomplete information actually incentivizes honest behavior and facilitates credible signaling. Because uncertain senders do not know whether a particular action will be interpreted as cooperative, they have little incentive to misrepresent, and instead honestly pursue their true goals. Thus, where cooperation is subjective, mutual uncertainty is “offsetting,” such that credible signals allow actors to quickly and accurately update their beliefs. We illustrate this logic through a case study of the Sino–Soviet split, and highlight the model's implications for contemporary U.S.–China relations. 相似文献
999.
Natur und Recht - Nachdem in NuR (2022, Heft 2, S. 77ff.) die Reichweite des wasserhaushaltsrechtlichen Planfeststellungsvorbehalts sowie Fragen der Verfahrenswahl erörtert wurden, behandeln... 相似文献
1000.