首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5934篇
  免费   611篇
  国内免费   32篇
系统科学   1095篇
丛书文集   9篇
教育与普及   37篇
理论与方法论   275篇
现状及发展   868篇
研究方法   2篇
综合类   4291篇
  2024年   8篇
  2023年   4篇
  2022年   17篇
  2021年   12篇
  2020年   10篇
  2019年   4篇
  2018年   730篇
  2017年   734篇
  2016年   433篇
  2015年   42篇
  2014年   9篇
  2013年   9篇
  2012年   276篇
  2011年   959篇
  2010年   831篇
  2009年   468篇
  2008年   531篇
  2007年   784篇
  2006年   16篇
  2005年   49篇
  2004年   134篇
  2003年   159篇
  2002年   65篇
  2001年   14篇
  2000年   17篇
  1999年   31篇
  1998年   39篇
  1997年   37篇
  1996年   18篇
  1995年   27篇
  1994年   26篇
  1993年   13篇
  1992年   15篇
  1991年   18篇
  1990年   12篇
  1989年   5篇
  1988年   14篇
  1987年   2篇
  1986年   3篇
  1985年   1篇
  1967年   1篇
排序方式: 共有6577条查询结果,搜索用时 15 毫秒
921.
《红楼梦》有三个模糊不清:故事的年代模糊不清,人物的年龄模糊不清,故事的地点模糊不清。本报告是对《红楼梦》故事的年代进行的专项审计,文章的独特之处是:揭开这些模糊不清的秘密,不是依靠复杂繁琐的史实考证和史料考证,而主要从《红楼梦》的文字叙述来寻找依据,进行逻辑推理和演绎推算;文章的基本内容是:红楼纪年的命名和时间,各个红楼年代的文章结构、审定证据和重要事件。  相似文献   
922.
AN EXTENSION OF TOPSIS FOR FUZZY MCDM BASED ON VAGUE SET THEORY   总被引:4,自引:1,他引:4  
1.Introduction The multicriteria decision-making problem(Kickert1978)is a kind of problem that all the alternatives in the choice set can be evaluated according to a number of criteria.A MCDM problem can be concisely expressed in matrix format as C1C2C n11112122122212nnm m m mnA x x xMA x x xA x x x=W={w1,w2,,wn}where A1,A2,,Am are possible alternatives among which decision-makers have to choose,C1,C2,,C n are the criteria with which alternative performance are measured,xi j is the rati…  相似文献   
923.
VIEWING URBAN DISRUPTIONS FROM A DECISION INFORMATICS PERSPECTIVE   总被引:2,自引:2,他引:2  
1. Introduction Urban infrastructures are the focus of terrorist acts because, quite simply, they produce the most visible impact, if not casualties. From the September 11, 2001 (i.e., “9/11”) attack on New York City’s World Trade Center to the more recent March 11, 2004, attack on Madrid’s commuter trains, it is obvious that urban centers are indeed vulnerable to such hideous acts. A systemic or holistic approach to securing the infrastructure systems that underpin an urban center isr…  相似文献   
924.
1. Introduction In his famous seminal book (Rogers 1962), Rogers introduced and popularized a generic framework for analyzing and describing how the mechanism of diffusion of innovations works inside a given population. In this general approach, “innovation” can of course be understood in a large way: it may indeed referto various contexts such as the learning of a new practice, the use of a new tool, the launch of a new product, etc. The strength of Rogers' point of view comes from the fac…  相似文献   
925.
This paper argues that agent-based simulation can be used as a way for testing Kansei Engineering methods which deal with the human reaction from sensory to mental state, that is, sensitivity, sense, sensibility, feeling, esthetics, emotion affection and intuition. A new fuzzy linear quantification method is tested in an artificial world by agent-based modeling and simulations, and the performance of the fuzzy linear method is compared with that of a genetic algorithm. The simulations can expand people's imagination and enhance people's intuition that the new fuzzy linear quantification method is effective.  相似文献   
926.
基于模糊预测的建设工程单方造价快速算法研究   总被引:4,自引:0,他引:4  
基于模糊理论和指数平滑预测相结合的方法,给出了以预测单方造价为基础的投标工程单方造价快报算法。其算法具有普遍的应用价值。  相似文献   
927.
设E是一致凸Banach空间,T:D(T)E→E非自映射m—增生算子,f∈E,作者获得了关于算子方程x+Tx=f解的迭代逼近,去掉了最近由Chidume建立的相关结果中关于E是q—一致光滑或一致光滑条件。  相似文献   
928.
在高等代数教科书中,一般讨论两个多项式的最大公因式求法,本文给出求几个多项式的最大公因式的一种方法。  相似文献   
929.
E-commerce has grown extraordinarily since the emergence of the internet, and many types of services are employed to accelerate this process. Service quality and productivity are two critical indicators to evaluate the competitiveness of e-commerce companies. Deciding which provision mode of e-commerce services (buy, sell, or self-provide) to adopt is a key operational strategy issue. This paper investigates the conditions and limitations of e-commerce services' optimal supply modes, and proposes a cost oriented infra-marginal model where service demand is considered an exogenous variable due to its non-elastic and unprofitable characteristics. By analyzing the main impact factors of this model, this paper infers provision mode selection strategies, which are determined by four factors: transaction cost, service price, service demand, and competitive advantages. Decision trees are derived from these strategies to help e-commerce companies make appropriate decisions. Finally, the proposed model's feasibility is verified by two case studies.  相似文献   
930.
In this paper, the generalized inverse eigenvalue problem for the (P,Q)-conjugate matrices and the associated approximation problem are discussed by using generalized singular value decomposition (GSVD). Moreover, the least residual problem of the above generalized inverse eigenvalue problem is studied by using the canonical correlation decomposition (CCD). The solutions to these problems are derived. Some numerical examples are given to illustrate the main results.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号