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71.
State-of-the-art theory solvers generally rely on an instantiation of the axioms of the theory, and depending on the solvers,
this instantiation is more or less explicit. This paper introduces a generic instantiation scheme for solving SMT problems,
along with syntactic criteria to identify the classes of clauses for which it is complete. The instantiation scheme itself
is simple to implement, and we have produced an implementation of the syntactic criteria that guarantee a given set of clauses
can be safely instantiated. We used our implementation to test the completeness of our scheme for several theories of interest
in the SMT community, some of which are listed in the last section of this paper. 相似文献
72.
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75.
Nicolas Prat Jacky Akoka Isabelle Comyn-Wattiau 《Expert systems with applications》2012,39(12):10420-10437
This paper proposes an MDA approach to knowledge engineering, centered on the CommonKADS knowledge model. The latter corresponds to the CIM level of MDA whereas PRR, which represents production rules and rulesets, corresponds to the PIM level. The paper explores the mapping between CommonKADS knowledge models and production rules and rulesets based on PRR. Mapping CommonKADS knowledge models into PRR is very useful, due to the fact that the CIM level remains relatively unexplored, despite its key role in MDA. This motivates our choice to focus on the CIM and PIM levels. Furthermore, the mapping between PIM and PSM (i.e. the implementation of production rules in specific rule-based systems) constitutes less of an issue. To map CommonKADS knowledge models into PRR production rules and rulesets, we propose and illustrate a set of transformations. To ease these transformations, we start by grouping elements of the CommonKADS knowledge models into so-called “inference groups”. We propose and illustrate an algorithm that defines these inference groups automatically. The definition of transformations between models (CIM to PIM levels) requires a specific metamodel for CommonKADS as well as a dedicated metamodel for PRR. Unlike PRR, there is no published CommonKADS metamodel. This paper proposes a comprehensive CommonKADS knowledge metamodel. We describe and discuss an example, applying the whole approach. 相似文献
76.
Logic for improving integrity checking in relational data bases⋆ 总被引:4,自引:0,他引:4
Jean-Marie Nicolas 《Acta Informatica》1982,18(3):227-253
Summary When an updating operation occurs on the current state of a data base, one has to ensure the new state obeys the integrity constraints. So, some of them have to be evaluated on this new state. The evaluation of an integrity constraint can be time consuming, but one can improve such an evaluation by taking advantage from the fact that the integrity constraint is satisfied in the current state. Indeed, it is then possible to derive a simplified form of this integrity constraint which is sufficient to evaluate in the new state in order to determine whether the initial constraint is still satisfied in this new state. The purpose of this paper is to present a simplification method yielding such simplified forms for integrity constraints. These simplified forms depend on the nature of the updating operation which is the cause of the state change. The operations of inserting, deleting, updating a tuple in a relation as well as transactions of such operations are considered. The proposed method is based on syntactical criteria and is validated through first order logic. Examples are treated and some aspects of the method application are discussed.The work reported in this paper was supported by the D.R.E.T. 相似文献
77.
Racemic β-butyrolactone was polymerized using chiral initiators obtained from the reaction of organometallic derivatives (ZnEt2, CdMe2, AlEt3) with R(−) 3,3 dimethyl-1,2 butanediol. With the zinc initiator, R(+) enantiomer is preferentially incorporated in the polymer chain with a stereoelectivity ratio rR equal to 1.6. Crude polymer was fractionated into a crystalline, predominantly isotactic, part and an amorphous heterotactic part, both optically active. Sites of different stereospecificities, present in the initiator, are all active for the stereoelective polymerization. With the cadmium initiator, S(−) enantiomer is preferentially polymerized (rs = 1.01), extending homosteric-antisteric rules previously established for thiiranes. Aluminium initiator leads to an homosteric process (rR = 1.1). Chiroptical properties (o.r.d. and c.d.) of polymers prepared with zinc initiator show a predominance of R-configurational units, indicating that ring-opening occurs by O-acyl cleavage with retention of configuration. 相似文献
78.
Characterization of Fractionated Soy Proteins Produced by a New Simplified Procedure 总被引:2,自引:0,他引:2
Nicolas A. Deak Patricia A. Murphy Lawrence A. Johnson 《Journal of the American Oil Chemists' Society》2007,84(2):137-149
It was possible to fractionate soy protein into two soy protein isolate fractions (>90% protein) enriched in either glycinin
or β-conglycinin by using a new simplified procedure (referred to as the Deak procedure) employing CaCl2 and NaHSO3. The Deak procedure produced fractions with higher yields of solids, protein, and isoflavones, and similar protein purities
as well as improved functional properties compared to fractions recovered by established, more complex soy protein fractionation
procedures. The Deak glycinin-rich fraction comprised 15.5% of the solids, 24.4% of the protein, and 20.5% of the isoflavones
in the starting soy flour, whereas the glycinin-rich fraction of the established procedure (Wu procedure) comprised only 11.6%
of the solids, 22.3% of the protein, and 9.6% of the isoflavones. The Deak β-conglycinin-rich fraction comprised 23.1% of
the solids, 37.1% of the protein, and 37.5% of the isoflavones in the starting soy flour, whereas the Wu β-conglycinin-rich
fraction comprised only 11.5% of the solids, 18.5% of the protein, and 3.3% of the isoflavones. Protein purities were >80%
for both fractions when using both procedures. The Wu procedure produced protein fractions with slightly higher solubilities
and similar surface hydrophobicities; whereas, the fractions produced by the Deak procedure had superior emulsification and
foaming properties and similar dynamic viscosity behaviors. 相似文献
79.
Victor D. Fachinotti Steven Le Corre Nicolas Triolet Manuel Bobadilla Michel Bellet 《International journal for numerical methods in engineering》2006,67(10):1341-1384
As an approach towards a better modelling of solidification problems, we introduce a thermo‐mechanical and macrosegregation model that considers a solidifying alloy as a binary mixture made of a liquid and a solid phase. Macroscopic conservation laws for mass, momentum and solute are obtained by spatial averaging of the respective microscopic conservation equations. Assuming local thermal equilibrium, a single equation for the conservation of the mixture energy is then written. A single equation can be obtained for the solute as well by invoking a proper microsegregation rule. The numerical implementation in a two‐dimensional finite element code is then detailed. Lastly, some examples of simulations of academic tests as well as industrial applications for continuous casting of steel slabs are discussed. They particularly enlighten the ability of the formulation to describe the formation of central macrosegregation during the secondary cooling of slab continuous casting processes. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
80.
Nicolas Maudet 《Autonomous Agents and Multi-Agent Systems》2003,7(3):229-233
Recently in the field of agent communication, many authors have adopted the view of interaction as a joint activity regulated by means of dialogue games. It is argued in particular that this approach should increase the flexibility of dialogues by allowing a variety of game compositions. In this research note, we present a framework suited to this feature. A preliminary attempt to capture the negotiation phase (which allows agents to agree upon the dialogue game currently regulating their conversation) is discussed. 相似文献