全文获取类型
收费全文 | 13705篇 |
免费 | 142篇 |
国内免费 | 50篇 |
专业分类
管理学 | 1656篇 |
劳动科学 | 26篇 |
民族学 | 171篇 |
人才学 | 1篇 |
人口学 | 2454篇 |
丛书文集 | 868篇 |
理论方法论 | 633篇 |
综合类 | 2121篇 |
社会学 | 4565篇 |
统计学 | 1402篇 |
出版年
2024年 | 6篇 |
2023年 | 17篇 |
2022年 | 54篇 |
2021年 | 47篇 |
2020年 | 31篇 |
2019年 | 47篇 |
2018年 | 1697篇 |
2017年 | 1707篇 |
2016年 | 1131篇 |
2015年 | 152篇 |
2014年 | 137篇 |
2013年 | 193篇 |
2012年 | 511篇 |
2011年 | 1362篇 |
2010年 | 1265篇 |
2009年 | 1066篇 |
2008年 | 1070篇 |
2007年 | 1251篇 |
2006年 | 295篇 |
2005年 | 435篇 |
2004年 | 400篇 |
2003年 | 339篇 |
2002年 | 212篇 |
2001年 | 111篇 |
2000年 | 79篇 |
1999年 | 51篇 |
1998年 | 21篇 |
1997年 | 32篇 |
1996年 | 64篇 |
1995年 | 21篇 |
1994年 | 20篇 |
1993年 | 11篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
This paper studies optimum designs for linear models when the errors are heteroscedastic. Sufficient conditions are given
in order to obtainD-, A- andE-optimum designs for a complete regression model from partial optimum designs for some sub-parameters. A result about optimality
for a complete model from the optimality for the submodels is included.
Supported by Junta de Andalucía, research group FQM244. 相似文献
82.
83.
Dwight R. Lee 《Journal of Labor Research》2003,24(3):437-446
Reverse mandated benefits is a government-mandated policy that requires employees to provide their employers with benefits
that workers would not provide otherwise. Of course, only those benefits would be mandated that are worth more to employers
than they cost, as determined by political authorities. My case for such a policy argues that it is at least as sensible as
policies mandating that employers provide benefits to their employees that would not be provided otherwise. 相似文献
84.
电力系统正常运行时,无功/电压控制目的是安全经济供电.而在紧急情况下,首要目标是运行的安全性,其次才是经济性.本文提出的局部网概念及其灵敏度矩阵,以及对电压违限严重性的分级和控制战略,使控制更为快速有效.此法更适用于当事故引起全系统运行数据不全时对局部网的电压控制. 相似文献
85.
In this paper, the task of determining expected values of sample moments, where the sample members have been selected based on noisy information, is considered. This task is a recurring problem in the theory of evolution strategies. Exact expressions for expected values of sums of products of concomitants of selected order statistics are derived. Then, using Edgeworth and Cornish-Fisher approximations, explicit results that depend on coefficients that can be determined numerically are obtained. While the results are exact only for normal populations, it is shown experimentally that including skewness and kurtosis in the calculations can yield greatly improved results for other distributions. 相似文献
86.
87.
将投资者信心指数引入MIDAS混频模型之中,可以考察新冠疫情背景下投资者信心对于中国宏观经济波动的影响。基于投资者信心指数和“三驾马车”对我国季度GDP增长率进行预测,通过实证发现:引入投资者信心指数的MIDAS混频模型在预测精准度方面和基准模型进行比较,预测精准度高于未加入投资者信心的模型,均方根残差比值更小;在多元MIDAS混频模型之中,加入投资者信心指数的回归模型对我国GDP的实时预报和短期预测结果更加稳定,可为决策者提供更加精确的参考区间;宏观经济的波动对投资者信心指数变化反应,和投资、消费和进出口相比是最灵敏的。这为定量追踪宏观经济波动提供了一个新的视角。 相似文献
88.
研究了平角涡虫(Planocerareticulata)脑神经节胆碱酯酶的组织化学定位.结果表明,胆碱酯酶阳性细胞分别分布于脑神经节的吻端腹侧面、前腹侧面、中央腹侧面和后背侧面的细胞层中,各阳性细胞在脑神经节中均为左右对称分布.前腹侧面阳性细胞的突起向背内侧延伸,经交叉后进入对侧纤维网中;中央腹侧面阳性细胞的突起向中线延伸形成联系;后背侧阳性细胞的突起向腹外侧延伸进入同侧纤维网中.神经节中央的神经纤维网中具有丰富的阳性纤维,前部反应较强,后端反应较弱.由脑神经节发出的各神经干均呈胆碱酯酶阳性反应. 相似文献
89.
Author of the highly acclaimed Borrowed Time: An AIDS Memoir (1988) and winner of the 1992 National Book Award for his autobiography Becoming a Man: Half a Life Story, Paul Monette died of complications from AIDS in Los Angeles on February 12, 1995. His most recent work, Last Watch of the Night: Essays Too Personal and Otherwise (1994), is his third volume in a trilogy of autobiographical writing on growing up gay, coming-out, and living with AIDS. A graduate of Phillips Academy and Yale University, Monette received a number of awards for his writing and his work as an outspoken voice in the battle against AIDS, including the National Book Award, three Lambda Literary awards, the PEN Center West Freedom to Write Award, and three honorary doctorate degrees, from Wesleyan University, the City University of New York, and the State University of New York at Oswego. A memorial service was held for Monette on Sunday, February 19, 1995, at the Directors Guild of America on Sunset Boulevard in Los Angeles. Paul Monette was 49. 相似文献
90.