全文获取类型
收费全文 | 8290篇 |
免费 | 174篇 |
国内免费 | 39篇 |
专业分类
管理学 | 416篇 |
民族学 | 27篇 |
人口学 | 145篇 |
丛书文集 | 244篇 |
理论方法论 | 141篇 |
综合类 | 2027篇 |
社会学 | 85篇 |
统计学 | 5418篇 |
出版年
2024年 | 6篇 |
2023年 | 33篇 |
2022年 | 61篇 |
2021年 | 68篇 |
2020年 | 130篇 |
2019年 | 242篇 |
2018年 | 269篇 |
2017年 | 508篇 |
2016年 | 181篇 |
2015年 | 198篇 |
2014年 | 279篇 |
2013年 | 2283篇 |
2012年 | 648篇 |
2011年 | 322篇 |
2010年 | 251篇 |
2009年 | 286篇 |
2008年 | 293篇 |
2007年 | 288篇 |
2006年 | 258篇 |
2005年 | 270篇 |
2004年 | 217篇 |
2003年 | 205篇 |
2002年 | 190篇 |
2001年 | 173篇 |
2000年 | 154篇 |
1999年 | 101篇 |
1998年 | 88篇 |
1997年 | 64篇 |
1996年 | 56篇 |
1995年 | 50篇 |
1994年 | 37篇 |
1993年 | 38篇 |
1992年 | 36篇 |
1991年 | 30篇 |
1990年 | 33篇 |
1989年 | 27篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 14篇 |
1983年 | 18篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 4篇 |
排序方式: 共有8503条查询结果,搜索用时 31 毫秒
921.
对微小钻头的寿命分布规律进行了研究,提出在本文的试验条件范围内,微小钻头寿命呈威布尔分布特点,并利用柯尔莫哥洛夫检验法进行了验证。 相似文献
922.
建立维拉帕米的反相高效液相色谱分析方法,并对其大鼠体内过程特性进行分析研完。方法:生物样品在碱性条件下经过正已烷一乙醚(30:70)提取,用Kromasil C_(18)反相柱(150mm×4.6mm,5μm),甲醇-水-三乙胺(70:30:0.1)为流动相,流速1.0mL.min~(-1),荧光检测波长为λ_(ex)275nm和λ_(ex)315nm。结果:方法回收率为92.3%~104.8%,测定血药浓度线性范围为8.5~85ng.mL~(-1)(r=0.9992),最低检测限0.6ng.ml~-。SD大鼠一次性灌胃盐酸维拉帕米片后血浆C-t曲线呈二室开放模型,达峰时间为(0.28±0.1)h。给药1.25h时,在主要的效应器官的浓度分布特点是:C_心>C_(大脑)>C_(小脑),在主要消除器官的浓度分布特点是:C_肝>C_肾>C_脾。结论:本法准确,灵敏度较高,可用于维拉帕米的体内过程研究。维拉帕米的肝首过效应应引起重视,主要由肾脏排泄。 相似文献
923.
Behavior analysts have offered accounts of the behavior involved in matching to sample and delayed matching to sample. But until recently have not offered a behavioral analysis of generalized matching-to-sample. The concept of joint control, however, seems especially suited to such an analysis The present study used a joint-control procedure to train five adult women to acquire a generalized sequencing behavior using an unfamiliar language. After joint-control training the participants were able to produce untrained picture sequences, and blocking the mediating response during the sequencing task resulted in a reduction in the number of accurate sequences. These results clearly support response mediation as a precurrent to various kinds of complex human behavior. 相似文献
924.
HANS‐GEORG MÜLLER 《Scandinavian Journal of Statistics》2005,32(2):223-240
Abstract. We review and extend some statistical tools that have proved useful for analysing functional data. Functional data analysis primarily is designed for the analysis of random trajectories and infinite‐dimensional data, and there exists a need for the development of adequate statistical estimation and inference techniques. While this field is in flux, some methods have proven useful. These include warping methods, functional principal component analysis, and conditioning under Gaussian assumptions for the case of sparse data. The latter is a recent development that may provide a bridge between functional and more classical longitudinal data analysis. Besides presenting a brief review of functional principal components and functional regression, we develop some concepts for estimating functional principal component scores in the sparse situation. An extension of the so‐called generalized functional linear model to the case of sparse longitudinal predictors is proposed. This extension includes functional binary regression models for longitudinal data and is illustrated with data on primary biliary cirrhosis. 相似文献
925.
刘顺 《山东师范大学学报(人文社会科学版)》2004,49(1):26-30
通指不是跟单指相对的概念,而是跟特指相对的概念,通指和特指构成定指范畴。通指主要分布在抽象事件句、判断句、"有"字句、抽象的形容词谓语句的主语位置上。通指主要的表现形式是单个名词,在抽象评议句中,可以是数量名短语,冠词性的"这"也常常表示通指。 相似文献
926.
Let Sp × p have a Wishart distribution with parameter matrix Σ and n degrees of freedom. We consider here the problem of estimating the precision matrix Σ?1 under the loss functions L1(σ) tr (σ) - log |σ| and L2(σ) = tr (σ). James-Stein-type estimators have been derived for an arbitrary p. We also obtain an orthogonal invariant and a diagonal invariant minimax estimator under both loss functions. A Monte-Carlo simulation study indicates that the risk improvement of the orthogonal invariant estimators over the James-Stein type estimators, the Haff (1979) estimator, and the “testimator” given by Sinha and Ghosh (1987) is substantial. 相似文献
927.
The autoregressive conditional intensity model proposed by Russell (1998) is a promising option for fitting multivariate high frequency irregularly spaced data. The authors acknowledge the validity of this model by showing the independence of its generalized residuals, a crucial assumption of the model formulation not readily recognized by researchers. The authors derive the large‐sample distribution of the autocorrelations of the generalized residual series and use it to construct a goodness‐of‐fit test for the model. Empirical results compare the performance of their test with other off‐the‐shelf tests such as the Ljung–Box test. They illustrate the use of their test with transaction records of the HSBC stock. 相似文献
928.
王世杰 《贵州工业大学学报(社会科学版)》2006,8(5):11-14
关于收入分配与经济增长的关系,学术界并没有定论。有些学者认为,现存收入分配政策是经济增长的必然结果;有些学者认为,确定的收入分配政策决定了经济增长的高度和深度。而所有的收入分配政策研究几乎都围绕着收入分配平等与否来展开。换句话说,主要是收入分配不平等有利于经济增长还是不利于经济增长。本文将从收入分配与个人努力程度的相关性的角度来阐述收入分配与经济增长之间的关系,从而为政府制定合理的收入分配政策提供理论依据。 相似文献
929.
ADELCHI AZZALINI 《Scandinavian Journal of Statistics》2005,32(2):159-188
Abstract. This paper provides an introductory overview of a portion of distribution theory which is currently under intense development. The starting point of this topic has been the so‐called skew‐normal distribution, but the connected area is becoming increasingly broad, and its branches include now many extensions, such as the skew‐elliptical families, and some forms of semi‐parametric formulations, extending the relevance of the field much beyond the original theme of ‘skewness’. The final part of the paper illustrates connections with various areas of application, including selective sampling, models for compositional data, robust methods, some problems in econometrics, non‐linear time series, especially in connection with financial data, and more. 相似文献
930.
本文对建国以来中国电信资费的规制制度进行四个阶段的划分,总结了每个阶段的资费政策和资费内容以及用户规模的发展。从实证数据上分析了每个阶段中国电信企业的经济效益,计算了电信用户每个阶段末期的固定通信和移动通信资费的市场平均价格,并对规制机构进行了管制成本趋势分析。得出了中国电信企业、电信用户和规制机构的利益在规制制度变迁中是保持增长的结论,中国电信资费的规制制度变迁是属于帕累托改进的,它不仅激励了电信企业的竞争与发展,提高了电信用户的利益,而且降低了政府实行管制的成本,有利于实现全社会福利最大化。 相似文献