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991.
992.
Katalin Friedl Gábor Ivanyos Miklos Santha Yves F. Verhoeven 《Theory of Computing Systems》2009,45(3):629-646
We present several results on the complexity of various forms of Sperner’s Lemma in the black-box model of computing. We give
a deterministic algorithm for Sperner problems over pseudo-manifolds of arbitrary dimension. The query complexity of our algorithm
is linear in the separation number of the skeleton graph of the manifold and the size of its boundary. As a corollary we get
an
deterministic query algorithm for the black-box version of the problem 2D-SPERNER, a well studied member of Papadimitriou’s complexity class PPAD. This upper bound matches the
deterministic lower bound of Crescenzi and Silvestri. The tightness of this bound was not known before. In another result
we prove for the same problem an
lower bound for its probabilistic, and an
lower bound for its quantum query complexity, showing that all these measures are polynomially related.
Research supported by the European Commission IST Integrated Project Qubit Application (QAP) 015848, the OTKA grants T42559
and T46234, and by the ANR Blanc AlgoQP grant of the French Research Ministry. 相似文献
993.
Ronen Gradwohl Moni Naor Benny Pinkas Guy N. Rothblum 《Theory of Computing Systems》2009,44(2):245-268
We consider cryptographic and physical zero-knowledge proof schemes for Sudoku, a popular combinatorial puzzle. We discuss
methods that allow one party, the prover, to convince another party, the verifier, that the prover has solved a Sudoku puzzle,
without revealing the solution to the verifier. The question of interest is how a prover can show: (i) that there is a solution
to the given puzzle, and (ii) that he knows the solution, while not giving away any information about the solution to the
verifier.
In this paper we consider several protocols that achieve these goals. Broadly speaking, the protocols are either cryptographic
or physical. By a cryptographic protocol we mean one in the usual model found in the foundations of cryptography literature.
In this model, two machines exchange messages, and the security of the protocol relies on computational hardness. By a physical
protocol we mean one that is implementable by humans using common objects, and preferably without the aid of computers. In
particular, our physical protocols utilize items such as scratch-off cards, similar to those used in lotteries, or even just
simple playing cards.
The cryptographic protocols are direct and efficient, and do not involve a reduction to other problems. The physical protocols
are meant to be understood by “lay-people” and implementable without the use of computers.
Research of R. Gradwohl was supported by US-Israel Binational Science Foundation Grant 2002246.
Research of M. Naor was supported in part by a grant from the Israel Science Foundation.
Research of B. Pinkas was supported in part by the Israel Science Foundation (grant number 860/06).
Research of G.N. Rothblum was supported by NSF grant CNS-0430450 and NSF grant CFF-0635297. 相似文献
994.
Classification of semantic relations between nominals 总被引:1,自引:0,他引:1
Roxana Girju Preslav Nakov Vivi Nastase Stan Szpakowicz Peter Turney Deniz Yuret 《Language Resources and Evaluation》2009,43(2):105-121
The NLP community has shown a renewed interest in deeper semantic analyses, among them automatic recognition of semantic relations
in text. We present the development and evaluation of a semantic analysis task: automatic recognition of relations between
pairs of nominals in a sentence. The task was part of SemEval-2007, the fourth edition of the semantic evaluation event previously
known as SensEval. Apart from the observations we have made, the long-lasting effect of this task may be a framework for comparing
approaches to the task. We introduce the problem of recognizing relations between nominals, and in particular the process
of drafting and refining the definitions of the semantic relations. We show how we created the training and test data, list
and briefly describe the 15 participating systems, discuss the results, and conclude with the lessons learned in the course
of this exercise. 相似文献
995.
Jimmy Lin G. Craig Murray Bonnie J. Dorr Jan Hajič Pavel Pecina 《Language Resources and Evaluation》2009,43(1):27-40
Thesauri and controlled vocabularies facilitate access to digital collections by explicitly representing the underlying principles
of organization. Translation of such resources into multiple languages is an important component for providing multilingual
access. However, the specificity of vocabulary terms in most thesauri precludes fully-automatic translation using general-domain
lexical resources. In this paper, we present an efficient process for leveraging human translations to construct domain-specific
lexical resources. This process is illustrated on a thesaurus of 56,000 concepts used to catalog a large archive of oral histories.
We elicited human translations on a small subset of concepts, induced a probabilistic phrase dictionary from these translations,
and used the resulting resource to automatically translate the rest of the thesaurus. Two separate evaluations demonstrate
the acceptability of the automatic translations and the cost-effectiveness of our approach.
相似文献
Jimmy LinEmail: |
996.
Bolette Sandford Pedersen Sanni Nimb Jørg Asmussen Nicolai Hartvig Sørensen Lars Trap-Jensen Henrik Lorentzen 《Language Resources and Evaluation》2009,43(3):269-299
This paper is a contribution to the discussion on compiling computational lexical resources from conventional dictionaries.
It describes the theoretical as well as practical problems that are encountered when reusing a conventional dictionary for
compiling a lexical-semantic resource in terms of a wordnet. More specifically, it describes the methodological issues of
compiling a wordnet for Danish, DanNet, from a monolingual basis, and not—as is often seen—by applying the translational expansion method with Princeton WordNet as the English source.
Thus, we apply as our basis a large, corpus-based printed dictionary of modern Danish. Using this approach, we discuss the
issues of readjusting inconsistent and/or underspecified hyponymy hierarchies taken from the conventional dictionary, sense
distinctions as opposed to the synonym sets of wordnets, generating semantic wordnet relations on the basis of sense definitions,
and finally, supplementing missing or implicit information. 相似文献
997.
Wilhelm Dolle 《Datenschutz und Datensicherheit - DuD》2009,33(3):183-188
Zusammenfassung Im Zeitalter der Informationstechnologie und der umfassenden Vernetzung vieler Systeme ben?tigt ein Dieb weder eine Brechstange
noch muss er im Schutze der Dunkelheit vorgehen. Vielmehr kann er über das Internet, oder lokale Netzwerke, kommen und gehen
wann er will, ohne sich der Gefahr einer Entdeckung und Verhaftung auszusetzen. In vielen F?llen ist ein solcher Einbrecher
l?ngst über alle Berge, bevor seine Tat überhaupt bemerkt wird. Trotzdem hinterl?sst er Spuren — deren Aufspürung und Analyse
die Aufgabe des Computer-Forensikers ist. Zur Unterstützung dieser Arbeit existiert eine Vielzahl an Open-Source-Werkzeugen,
die es durchaus mit ihrer kommerziellen Konkurrenz aufnehmen k?nnen. 相似文献
998.
The maximum entropy principle (MEP) is used to generate a natural probability distribution among the many possible that have
the same moment conditions. The MEP can accommodate higher order moment information and therefore facilitate a higher quality
PDF model. The performance of the MEP for PDF estimation is studied by using more than four moments. For the case with four
moments, the results are compared with those by the Pearson system. It is observed that as accommodating higher order moment,
the estimated PDF converges to the original one. A sensitivity analysis formulation of the failure probability based on the
MEP is derived for reliability-based design optimization (RBDO) and the accuracy is compared with that by finite difference
method (FDM). Two RBDO examples including a realistic three-dimensional wing design are solved by using the derived sensitivity
formula and the MEP-based moment method. The results are compared with other methods such as TR-SQP, FAMM + Pearson system,
FFMM + Pearson system in terms of accuracy and efficiency. It is also shown that an improvement in the accuracy by including
more moment terms can increase numerical efficiency of optimization for the three-dimensional wing design. The moment method
equipped with the MEP is found flexible and well adoptable for reliability analysis and design. 相似文献
999.
Solving engineering design and resources optimization via multiobjective evolutionary algorithms (MOEAs) has attracted much
attention in the last few years. In this paper, an efficient multiobjective differential evolution algorithm is presented
for engineering design. Our proposed approach adopts the orthogonal design method with quantization technique to generate
the initial archive and evolutionary population. An archive (or secondary population) is employed to keep the nondominated
solutions found and it is updated by a new relaxed form of Pareto dominance, called Pareto-adaptive ϵ-dominance (paϵ-dominance), at each generation. In addition, in order to guarantee to be the best performance produced, we propose a new
hybrid selection mechanism to allow the archive solutions to take part in the generating process. To handle the constraints,
a new constraint-handling method is employed, which does not need any parameters to be tuned for constraint handling. The
proposed approach is tested on seven benchmark constrained problems to illustrate the capabilities of the algorithm in handling
mathematically complex problems. Furthermore, four well-studied engineering design optimization problems are solved to illustrate
the efficiency and applicability of the algorithm for multiobjective design optimization. Compared with Nondominated Sorting
Genetic Algorithm II, one of the best MOEAs available at present, the results demonstrate that our approach is found to be
statistically competitive. Moreover, the proposed approach is very efficient and is capable of yielding a wide spread of solutions
with good coverage and convergence to true Pareto-optimal fronts. 相似文献
1000.
Reliability-based design optimization of problems with correlated input variables using a Gaussian Copula 总被引:4,自引:2,他引:2
The reliability-based design optimization (RBDO) using performance measure approach for problems with correlated input variables
requires a transformation from the correlated input random variables into independent standard normal variables. For the transformation
with correlated input variables, the two most representative transformations, the Rosenblatt and Nataf transformations, are
investigated. The Rosenblatt transformation requires a joint cumulative distribution function (CDF). Thus, the Rosenblatt
transformation can be used only if the joint CDF is given or input variables are independent. In the Nataf transformation,
the joint CDF is approximated using the Gaussian copula, marginal CDFs, and covariance of the input correlated variables.
Using the generated CDF, the correlated input variables are transformed into correlated normal variables and then the correlated
normal variables are transformed into independent standard normal variables through a linear transformation. Thus, the Nataf
transformation can accurately estimates joint normal and some lognormal CDFs of the input variable that cover broad engineering
applications. This paper develops a PMA-based RBDO method for problems with correlated random input variables using the Gaussian
copula. Several numerical examples show that the correlated random input variables significantly affect RBDO results. 相似文献