全文获取类型
收费全文 | 925篇 |
免费 | 47篇 |
国内免费 | 27篇 |
专业分类
化学 | 67篇 |
力学 | 122篇 |
综合类 | 14篇 |
数学 | 661篇 |
物理学 | 135篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 19篇 |
2017年 | 20篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 53篇 |
2013年 | 53篇 |
2012年 | 55篇 |
2011年 | 54篇 |
2010年 | 52篇 |
2009年 | 68篇 |
2008年 | 63篇 |
2007年 | 70篇 |
2006年 | 54篇 |
2005年 | 48篇 |
2004年 | 33篇 |
2003年 | 32篇 |
2002年 | 29篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 23篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有999条查询结果,搜索用时 15 毫秒
61.
Hideaki Matsunaga 《Proceedings of the American Mathematical Society》2008,136(12):4305-4312
For a linear delay differential system with two coefficients and one delay, we establish some necessary and sufficient conditions on the asymptotic stability of the zero solution, which are composed of delay-dependent and delay-independent stability criteria. On the former criterion, the range of the delay is explicitly given.
62.
Raymond Bisdorff Patrick Meyer Marc Roubens 《4OR: A Quarterly Journal of Operations Research》2008,6(2):143-165
The main concern of this article is to present the R
UBIS method for tackling the choice problem in the context of multiple criteria decision aiding. Its genuine purpose is to help
a decision maker to determine a single best decision alternative. Methodologically we focus on pairwise comparisons of these
alternatives which lead to the concept of bipolar-valued outranking digraph. The work is centred around a set of five pragmatic
principles which are required in the context of a progressive decision aiding methodology. Their thorough study and implementation
in the outranking digraph lead us to define a choice recommendation as an extension of the classical digraph kernel concept.
相似文献
63.
It is well known that classic theorems of Markov and Lukach for real polynomials which have a constant sign on a segment are ineffective. In this paper we obtain criteria for the constant sign property on a segment for real polynomials of the fourth degree and formulate certain their generalizations. The mentioned criteria are stated in terms of the coefficients of the polynomials under consideration. 相似文献
64.
Georgios D. Samaras Nikolaos F. Matsatsinis Constantin Zopounidis 《European Journal of Operational Research》2008
The paper describes a multicriteria decision support system which aims at presenting an evaluation of the Athens Stock Exchange (ASE) stocks, on the basis of fundamental analysis. The system evaluates the stocks based on the method of fundamental analysis ratios, which is the most appropriate evaluation approach regarding investment decisions within a long term horizon. In addition to quantitative data deriving from fundamental analysis, the system uses qualitative data as well, in order to improve the reliability of the evaluation. The system introduced in this paper, utilises multicriteria analysis methodologies in order to rank the stocks by placing the best stock first and the worst last. Stock evaluation considers the specific characteristics of the potential investor, as well as his attitude towards undertaken risk. The final output of the system is four stock rankings which respond to four different criteria groups, depending on the type of accounting plan each listed company belongs to. The system incorporates a large volume of relevant information and operates in ‘real world conditions’ since its data are constantly updated. Finally, the system is intended for both institutional and private investors. 相似文献
65.
V. V. Podinovski 《Computational Mathematics and Mathematical Physics》2008,48(11):1981-1998
Multicriteria decision-making problems under bounded (above, below, or from both sides) continuous or discrete criteria are considered. Methods for comparing variants of solutions using the information accumulated in the form of interval estimates of replacing the values of some criteria by the values of others (such replacements are called tradeoffs; in other words, this can be considered as a compensation of the deterioration of some criteria by improving the values of others) are proposed along with simple consistency conditions of such information. The issue of constructing the set of nondominated variants is discussed. 相似文献
66.
The aim of this paper is to generalize the way of computing the credibility of outranking in a multiple criteria aggregation procedure, in view of taking into account two new effects called reinforced preference and counter-veto. These effects concern only those criteria for which, as soon as action a is “judged very strongly preferred” to action b, one wishes that the credibility of outranking of a over b is greater than that for the case where (all things equal elsewhere) the preference is not “judged very strong”. To achieve this goal, we propose two complementary ways. The first one involves a reinforced preference threshold which affects the concordance degree, and the second one involves a counter-veto threshold which affects the insertion of discordance degree in the calculation of the credibility of outranking. The introduction of these two new effects remains compatible with the handling of ordinal preference scales. The resulting new index of the credibility of outranking can be used, in particular, in ELECTRE methods. 相似文献
67.
Erhan Erkut Avraam Karagiannidis George Perkoulidis Stevanus A. Tjandra 《European Journal of Operational Research》2008
Up to 2002, Hellenic Solid Waste Management (SWM) policy specified that each of the country’s 54 prefectural governments plan its own SWM system. After 2002, this authority was shifted to the country’s 13 regions entirely. In this paper, we compare and contrast regional and prefectural SWM planning in Central Macedonia. To design the prefectural plan, we assume that each prefecture must be self-sufficient, and we locate waste facilities in each prefecture. In contrast, in the regional plan, we assume cooperation between prefectures and locate waste facilities to serve the entire region. We present a new multicriteria mixed-integer linear programming model to solve the location–allocation problem for municipal SWM at the regional level. We apply the lexicographic minimax approach to obtain a “fair” nondominated solution, a solution with all normalized objectives as equal to one another as possible. A solution to the model consists of locations and technologies for transfer stations, material recovery facilities, incinerators and sanitary landfills, as well as the waste flow between these locations. 相似文献
68.
Multiple criteria analysis (MCA) is a framework for evaluating decision options against multiple criteria. Numerous techniques for solving an MCA problem are available. This paper applies MCA to six water management decision problems. The MCA methods tested include weighted summation, range of value, PROMTHEE II, Evamix and compromise programming. We show that different MCA methods were in strong agreement with high correlations amongst rankings. In the few cases where strong disagreement between MCA methods did occur it was due to presence of mixed ordinal-cardinal data in the evaluation matrix. The results suggest that whilst selection of the MCA technique is important more emphasis is needed on the initial structuring of the decision problem, which involves choosing criteria and decision options. 相似文献
69.
70.
Fazal M. Mahomed I. Naeem Asghar Qadir 《Nonlinear Analysis: Real World Applications》2009,10(6):3404-DECMA
We provide linearizability criteria for a class of systems of two third-order ordinary differential equations that is cubically nonlinear in the first derivative, by differentiating a system of second-order quadratically nonlinear ordinary differential equations and using the original system to replace the second derivatives. The procedure developed splits into two cases: those for which the coefficients are constant and those for which they are variables. Both cases are discussed and examples given. 相似文献