全文获取类型
收费全文 | 6298篇 |
免费 | 515篇 |
国内免费 | 6篇 |
学科分类
工业技术 | 6819篇 |
出版年
2024年 | 32篇 |
2023年 | 72篇 |
2022年 | 92篇 |
2021年 | 206篇 |
2020年 | 207篇 |
2019年 | 167篇 |
2018年 | 324篇 |
2017年 | 350篇 |
2016年 | 404篇 |
2015年 | 235篇 |
2014年 | 321篇 |
2013年 | 662篇 |
2012年 | 404篇 |
2011年 | 461篇 |
2010年 | 346篇 |
2009年 | 338篇 |
2008年 | 305篇 |
2007年 | 294篇 |
2006年 | 195篇 |
2005年 | 171篇 |
2004年 | 145篇 |
2003年 | 133篇 |
2002年 | 158篇 |
2001年 | 85篇 |
2000年 | 64篇 |
1999年 | 45篇 |
1998年 | 57篇 |
1997年 | 58篇 |
1996年 | 52篇 |
1995年 | 41篇 |
1994年 | 27篇 |
1993年 | 28篇 |
1992年 | 21篇 |
1991年 | 23篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1986年 | 11篇 |
1985年 | 35篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1972年 | 12篇 |
排序方式: 共有6819条查询结果,搜索用时 15 毫秒
61.
Béatrice Creusillet François Irigoin 《International journal of parallel programming》1996,24(6):513-546
Many program optimizations require exact knowledge of the sets of array elements that are referenced in or that flow between statements or procedures. Some examples are array privatization, generation of communications in distributed memory machines, or compile-time optimization of cache behavior in hierarchical memory machines. Exact array region analysis is introduced in this article. These regions exactly represent the effects of statements and procedures upon array variables. To represent the flow of these data, we also introduce two new types of array region analyses: in and out regions. The intraprocedural propagation is presented, as well as a general linear framework for interprocedural analyses, which handles array reshapes. The intra- and inter-procedural propagation of array regions is implemented in pips, the interprocedural parallelizer of fortran programs developed at École des mines de Paris. 相似文献
62.
This paper addresses the problem of automated code generation for a High Level Architecture compliant federate application given its behavior model. The behavior model is a part of the architectural model of a federation that the federate can participate in. The federate behavior model is based on Live Sequence Charts, adopted as the behavioral specification formalism in the Federation Architecture Metamodel (FAMM). FAMM serves as a formal language for describing federation architectures. An objective is to help the testing of federation architecture by means of its prototype implementation early in the development lifecycle. A further objective is to help developers construct complete federate applications that are well modularized. The approach to achieve these objectives is aspect‐oriented in that the generated code, which handles the federate's interactions with a federation execution, serves as the base code, where the computation logic is to be weaved as an aspect. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
63.
A multi‐input–multi‐output extension of the well‐known two control degrees‐of‐freedom disturbance observer architecture that decouples the problem into single‐input–single‐output disturbance observer loops is presented in this paper. Robust design based on mapping D‐stability and the frequency domain specifications of weighted sensitivity minimization and phase margin bound to a chosen controller parameter space is presented as a part of the proposed design approach. The effect of the choice of disturbance observer Q filter on performance is explained with a numerical example. This is followed by the use of structured singular values in the robustness analysis of disturbance observer controlled systems subject to structured, real parametric and mixed uncertainty in the plant. A design and simulation study based on a four wheel active car steering control example is used to illustrate the methods presented in the paper. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
64.
Véronique Souchère Laurent Millair Javier Echeverria François Bousquet Christophe Le Page Michel Etienne 《Environmental Modelling & Software》2010,25(11):1359-1370
Erosive runoff is a recurring problem and is a source of sometimes deadly muddy floods in the Pays de Caux (France). The risk results from a conjunction of natural factors and human activity. Efficient actions against runoff in agricultural watersheds are well known. However they are still difficult to implement as they require co-operation between stakeholders. Local actors thus need tools to help them understand the collective consequences of their individual decisions and help to initiate a process of negotiation between them. We decided to use a participatory approach called companion modelling (ComMod), and, in close collaboration with one of the first group of local stakeholders, to create a role-playing game (RPG) to facilitate negotiations on the future management of erosive runoff. This paper describes and discusses the development of the RPG and its use with other groups of local stakeholders within the framework of two game sessions organized by two different watershed management committees. During the joint construction step, stakeholders shared their viewpoints about the environment, agents, rules, and how to model runoff in preparation for the creation of the RPG. During the RPG sessions, two groups of eight players, including farmers, mayors and watershed advisors, were confronted with disastrous runoff in a fictive agricultural watershed. Results showed that they managed to reduce runoff by 20–50% by engaging a dialogue about grass strips, storage ponds and management of the intercrop period. However, further progress is still needed to better control runoff through the implementation of better agricultural practices because, during the RPG sessions, the watershed advisors did not encourage farmers to do so. Because of the complexity of management problems, results of jointly constructing the game and the RPG sessions showed that modelling and simulation can be a very useful way of accompanying the collective learning process. This new way of working was welcomed by the participants who expressed their interest in organizing further RPG sessions. 相似文献
65.
Jean-François Collard Pierre Duysinx Paul Fisette 《Structural and Multidisciplinary Optimization》2010,42(3):403-415
This paper presents a novel approach to optimize the design of planar mechanisms with revolute joints for function generation
or path synthesis. The proposed method is based on the use of an extensible-link mechanism model whose strain energy is minimized
to find the optimal rigid design. This enables us to get rid of assembly constraints and the use of natural coordinates makes
the objective function simpler. Two optimization strategies are developed and then discussed. The first one relies on alternate
optimizations of design parameters and point coordinates. The second one uses multiple partial syntheses as starting point
for a full synthesis process. The question of finding the global optimum is also addressed and developed. A simple algorithm
is proposed to find several local optima among which the designer may choose the best one taking other criteria into account
(e.g. stiffness, collision, size,...). Three applications are presented to illustrate the strategies while mentioning their
limits. 相似文献
66.
The accelerating interaction between technology and tourism has changed radically the efficiency and effectiveness of tourism organizations, as well as how consumers interact with organizations. In this study, a Web based intelligent framework for travel agencies is proposed that offers customers a fast and reliable response service in a less costly manner. The proposed framework integrates case-based reasoning (CBR) system with a well-known multi criteria decision making (MCDM) technique, namely Analytic Hierarchy Process, to enhance the accuracy and speed in case matching in tourism destination planning. The integration of two techniques enables taking advantages of their strengths and complements each other’s weaknesses. A case study is performed to demonstrate how this framework can facilitate intelligent decision support by retrieving best-fitted responses for customers. 相似文献
67.
In this paper, regression analyses (RA) are presented for the neutronic calculation of ThO2 mixed 244CmO2 fuel with different neutronic parameters for various coolants, natural lithium, Li20Sn80 and Flinabe, respectively. The tritium breeding ratio (TBR), energy multiplication factor (M), total fission rate (Σf) and 232Th(n, γ) reaction is computed by XSDRNPM. In addition, this numerical results are estimated by RA depends on neutronic parameters and the empirical equations for neutronic performance are acquired. The results obtained by using XSDRNPM and the results of the RA, obtained empirical equations, are compared. The empirical equations indicate that RA can successfully be used for the prediction of the neutronic performance parameters in the hybrid reactor with a high degree of accuracy. In addition, correlation matrix is calculated to determined statistical relationships between variables TBR, M, Σf, and 232Th(n, γ). 相似文献
68.
Sustainable supply chain management (SSCM) provides economic, social end environmental requirements in material and service flows occurring between suppliers, manufacturers and customers. SSCM structure is considered as a prerequisite for a sustainable success. Thus designing an effective SCM structure provides competitive advantages for the companies. In order to achieve an effective design of this structure, it is possible to apply quality function deployment (QFD) approach which is successfully applied as an effective product and system development tool. This study presents a decision framework where analytic network process (ANP) integrated QFD and zero-one goal programming (ZOGP) models are used in order to determine the design requirements which are more effective in achieving a sustainable supply chain (SSC). The first phase of the QFD is the house of quality (HOQ) which transforms customer requirements into product design requirements. In this study, after determining the sustainability requirements named customer requirements (CRs) and design requirements (DRs) of a SSC, ANP is employed to determine the importance levels in the HOQ considering the interrelationships among the DRs and CRs. Furthermore ZOGP approach is used to take into account different objectives of the problem. The proposed method is applied through a case study and obtained results are discussed. 相似文献
69.
Florent Peres Bernard Berthomieu François Vernadat 《Discrete Event Dynamic Systems》2011,21(3):395-424
Complex systems are often designed and built from smaller pieces, called components. Components are open sub-systems meant
to be combined (or composed) to form other components or closed systems. It is well known that Petri nets allow such a component
based modeling, relying on parallel composition and transition synchronization. However, synchronizing transitions that carry
temporal constraints does not yield a compositional method for assembling components, a highly desirable property. The paper
addresses this particular problem: how to build complex systems in a compositional manner from components specified by Time
Petri nets (TPN). A first solution is proposed, adequate for a particular subclass of Time Petri nets but significantly increasing the complexity
of components. Then an improved solution is developed, relying on an extension of Time Petri nets with two relations added
on transitions. This latter solution requires a much simpler transformation of nets, does not significantly increase their
complexity, and is applicable to a larger class of TPN. 相似文献
70.
Julien Fleureau Karim Bensalah Denis Rolland Olivier Lavastre Nathalie Rioux-Leclercq François Guillé Jean-Jacques Patard Renaud de Crevoisier Lotfi Senhadji 《Expert systems with applications》2011,38(11):14301-14306
In this study, we propose to evaluate the potential of Raman spectroscopy (RS) to assess renal tumours at surgery. Different classes of Raman renal spectra acquired during a clinical protocol are discriminated using support vector machines classifiers. The influence on the classification scores of various preprocessing steps generally involved in RS are also investigated and evaluated in the particular context of renal tumour characterization. Encouraging results show the interest of RS to evaluate kidney cancer and suggest the potential of this technique as a surgical assistance during partial nephrectomy. 相似文献