全文获取类型
收费全文 | 10448篇 |
免费 | 824篇 |
国内免费 | 222篇 |
专业分类
系统科学 | 1299篇 |
丛书文集 | 121篇 |
教育与普及 | 80篇 |
理论与方法论 | 293篇 |
现状及发展 | 892篇 |
研究方法 | 12篇 |
综合类 | 8796篇 |
自然研究 | 1篇 |
出版年
2024年 | 28篇 |
2023年 | 42篇 |
2022年 | 104篇 |
2021年 | 108篇 |
2020年 | 91篇 |
2019年 | 37篇 |
2018年 | 781篇 |
2017年 | 791篇 |
2016年 | 504篇 |
2015年 | 172篇 |
2014年 | 213篇 |
2013年 | 190篇 |
2012年 | 497篇 |
2011年 | 1189篇 |
2010年 | 1048篇 |
2009年 | 696篇 |
2008年 | 799篇 |
2007年 | 1016篇 |
2006年 | 257篇 |
2005年 | 259篇 |
2004年 | 284篇 |
2003年 | 281篇 |
2002年 | 208篇 |
2001年 | 163篇 |
2000年 | 123篇 |
1999年 | 231篇 |
1998年 | 165篇 |
1997年 | 179篇 |
1996年 | 140篇 |
1995年 | 154篇 |
1994年 | 141篇 |
1993年 | 98篇 |
1992年 | 104篇 |
1991年 | 75篇 |
1990年 | 71篇 |
1989年 | 76篇 |
1988年 | 78篇 |
1987年 | 42篇 |
1986年 | 41篇 |
1985年 | 15篇 |
1983年 | 1篇 |
1967年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Different from traditional tax audit, supervision with self-audit is a combination of audit by the taxpayer himself and audit by the tax authority. This paper mainly studies a taxpayer's optimal policy of tax evasion under supervision with self-audit and its related properties, in order to deduce some effective suggestions and theoretical bases to restrain tax evasion. Assuming that only a certain proportion of evaded tax can be discovered when the audit is executed, the authors first formulate a static model with self-audit. This model is divided into two stages. At the first stage, taxpayers declare their taxes, then the tax authority chooses audit objects, based on a known probability, and announces the result; if the taxpayer is chosen, he will enter the second stage, during which he has a chance to pay the evaded tax and the corresponding late fees and then is audited by the tax authority. The authors show the existence and uniqueness of the optimal amount of tax evasion at the first stage and the optimal proportion to self-expose at the second stage. The authors also discuss the related properties of the interior solution, and do elasticity analyses on some parameters. Besides, the authors extend the static model into the corresponding two-period model, and study the existence and uniqueness of the solution of the extended model. Finally, under the assumption that tax evasion can only be discovered with a certain probability when the audit is executed, the authors formulate another static model with self-audit and investigate its properties. 相似文献
72.
<正>Autocorrelation is prevalent in continuous production processes,such as the processes in the chemical and pharmaceutical industries.With the development of measurement technology and data acquisition technology,sampling frequency is getting higher and the existence of autocorrelation cannot be ignored.This paper analyzes five estimation schemes of process capability for autocorrelated data.Comparisons among these schemes are discussed for small sample and large sample.In conclusion,this paper gives a procedure of process capability analysis for autocorrelated data. 相似文献
73.
Patent documents are unique external sources of information that reveal the core technology underlying new inventions.Patents also serve as a strategic data source that can be mined to discover state-of-the-art technical development and subsequently help guide R&D investments.This research incorporates an ontology schema to extract and represent patent concepts.A clustering algorithm with non-exhaustive overlaps is proposed to overcome deficiencies with exhaustive clustering methods used in patent mining and technology discovery.The non-exhaustive clustering approach allows for the clustering of patent documents with overlapping technical findings and claims,a feature that enables the grouping of patents that define related key innovations.Legal advisors can use this approach to study potential cases of patent infringement or devise strategies to avoid litigation.The case study demonstrates the use of non-exhaustive overlaps algorithm by clustering US and Japan radio frequency identification (RFID) patents and by analyzing the legal implications of automated discovery of patent infringement. 相似文献
74.
The relationship between tacit knowledge and informal networks has not been fully explored.Tacit knowledge cannot be well managed directly,because it is deeply embedded in individual actions and experiences.This study proposes an approach to managing informal networks as a new middle way to facilitate the sharing and transferring of tacit knowledge,owing to the fact that tacit knowledge is mostly shared and transferred through informal networks.To support the idea of the approach,an empirical case study of applying the approach to management of a large scientific project is also included.Our findings suggest that informal networks play essential roles for management of tacit knowledge,and thus good management of informal networks can lead to efficient sharing and transferring of tacit knowledge. 相似文献
75.
76.
77.
基于活动轮廓模型的人脸特征提取方法的研究 总被引:3,自引:0,他引:3
根据活动轮廓模型理论 ,提出了提取人脸面部特征的系列算法 ,特征是精确的轮廓描述而非简单的数字表达. 相似文献
78.
79.
A hybrid approach of DEA (data envelopment analysis) and TOPSIS (technique for order performance (preference) by similarity
to ideal solution) is proposed for multiple criteria decision analysis in emergency management. Two DEA-based optimization
models are constructed to facilitate identifying parameter information regarding criterion weights and quantifying qualitative
criteria in TOPSIS. An emergency management case study utilizing data from the Emergency Management Australia (EMA) Disasters
Database is provided to demonstrate the feasibility of the proposed analysis procedure. 相似文献
80.
基于图切割的图像分割是近几年发展的一项新技术,但随着图像大小及空间维数的增加,图切割的运算量成为负担。针对运动分割提出了一种快速图切割方法,利用运动分割的特点将差分图像中不变的背景映射为一点或几点,然后参与网络图的构造和图切割的求解,以减少图切割运算量。通过实验将这种快速方法应用于2D图切割和3D图切割,对图像序列的运动目标分别进行了自动分割。实验结果表明,这种快速图切割方法不仅大大地降低了存储消耗,提高了运算速度,而且也获得了良好的分割结果。结果证明这种方法在运动目标的分割中是行之有效的。 相似文献