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991.
Marcelo Siqueira Longin Jan Latecki Nicholas Tustison Jean Gallier James Gee 《Journal of Mathematical Imaging and Vision》2008,30(3):249-274
We present here a new randomized algorithm for repairing the topology of objects represented by 3D binary digital images.
By “repairing the topology”, we mean a systematic way of modifying a given binary image in order to produce a similar binary
image which is guaranteed to be well-composed. A 3D binary digital image is said to be well-composed if, and only if, the square faces shared by background and foreground
voxels form a 2D manifold. Well-composed images enjoy some special properties which can make such images very desirable in
practical applications. For instance, well-known algorithms for extracting surfaces from and thinning binary images can be
simplified and optimized for speed if the input image is assumed to be well-composed. Furthermore, some algorithms for computing
surface curvature and extracting adaptive triangulated surfaces, directly from the binary data, can only be applied to well-composed
images. Finally, we introduce an extension of the aforementioned algorithm to repairing 3D digital multivalued images. Such
an algorithm finds application in repairing segmented images resulting from multi-object segmentations of other 3D digital
multivalued images.
相似文献
James GeeEmail: |
992.
This paper is concerned with the derivation of infinite schedules for timed automata that are in some sense optimal. To cover
a wide class of optimality criteria we start out by introducing an extension of the (priced) timed automata model that includes
both costs and rewards as separate modelling features. A precise definition is then given of what constitutes optimal infinite
behaviours for this class of models. We subsequently show that the derivation of optimal non-terminating schedules for such
double-priced timed automata is computable. This is done by a reduction of the problem to the determination of optimal mean-cycles
in finite graphs with weighted edges. This reduction is obtained by introducing the so-called corner-point abstraction, a
powerful abstraction technique of which we show that it preserves optimal schedules.
This work has been mostly done while visiting CISS at Aalborg University in Denmark and has been supported by CISS and by
ACI Cortos, a program of the French Ministry of Research. 相似文献
993.
Sagar Chaki Edmund Clarke Natasha Sharygina Nishant Sinha 《Formal Methods in System Design》2008,32(3):235-266
This paper presents an automated and compositional procedure to solve the substitutability problem in the context of evolving software systems. Our solution contributes two
techniques for checking correctness of software upgrades: (1) a technique based on simultaneous use of over-and under-approximations
obtained via existential and universal abstractions; (2) a dynamic assume-guarantee reasoning algorithm—previously generated component assumptions are reused and altered on-the-fly to prove
or disprove the global safety properties on the updated system. When upgrades are found to be non-substitutable, our solution
generates constructive feedback to developers showing how to improve the components. The substitutability approach has been
implemented and validated in the ComFoRT reasoning framework, and we report encouraging results on an industrial benchmark.
This is an extended version of a paper, Dynamic Component Substitutability Analysis, published in the Proceedings of the Formal Methods 2005 Conference, Lecture Notes in Computer Science, vol. 3582, by the
same authors. This research was sponsored by the National Science Foundation under grant nos. CNS-0411152, CCF-0429120, CCR-0121547,
and CCR-0098072, the Semiconductor Research Corporation under grant no. TJ-1366, the US Army Research Office under grant no.
DAAD19-01-1-0485, the Office of Naval Research under grant no. N00014-01-1-0796, the ICAST project and the Predictable Assembly
from Certifiable Components (PACC) initiative at the Software Engineering Institute, Carnegie Mellon University. The views
and conclusions contained in this document are those of the authors and should not be interpreted as representing the official
policies, either expressed or implied, of any sponsoring institution, the US government or any other entity. 相似文献
994.
Elisa Bertino Giovanna Guerrini Marco Mesiti 《Journal of Intelligent Information Systems》2008,30(1):55-92
Measuring the structural similarity between an XML document and a DTD has many relevant applications that range from document
classification and approximate structural queries on XML documents to selective dissemination of XML documents and document
protection. The problem is harder than measuring structural similarity among documents, because a DTD can be considered as
a generator of documents. Thus, the problem is to evaluate the similarity between a document and a set of documents. An effective
structural similarity measure should face different requirements that range from considering the presence and absence of required
elements, as well as the structure and level of the missing and extra elements to vocabulary discrepancies due to the use
of synonymous or syntactically similar tags. In the paper, starting from these requirements, we provide a definition of the
measure and present an algorithm for matching a document against a DTD to obtain their structural similarity. Finally, experimental
results to assess the effectiveness of the approach are presented. 相似文献
995.
In our previous work, we introduced a computational architecture that effectively supports the tasks of continuous monitoring
and of aggregation querying of complex domain meaningful time-oriented concepts and patterns (temporal abstractions), in environments featuring large volumes of continuously arriving and accumulating time-oriented raw data. Examples include
provision of decision support in clinical medicine, making financial decisions, detecting anomalies and potential threats
in communication networks, integrating intelligence information from multiple sources, etc. In this paper, we describe the
general, domain-independent but task-specific problem-solving method underling our computational architecture, which we refer
to as incremental knowledge-based temporal abstraction (IKBTA). The IKBTA method incrementally computes temporal abstractions by maintaining persistence and validity of continuously computed
temporal abstractions from arriving time-stamped data. We focus on the computational framework underlying our reasoning method,
provide well-defined semantic and knowledge requirements for incremental inference, which utilizes a logical model of time,
data, and high-level abstract concepts, and provide a detailed analysis of the computational complexity of our approach. 相似文献
996.
Gemma Robles 《Journal of Logic, Language and Information》2008,17(2):161-181
In this paper, consistency is understood in the standard way, i.e. as the absence of a contradiction. The basic constructive
logic BKc4, which is adequate to this sense of consistency in the ternary relational semantics without a set of designated points, is
defined. Then, it is shown how to define a series of logics by extending BKc4 up to minimal intuitionistic logic. All logics defined in this paper are paraconsistent logics. 相似文献
997.
Marian Counihan 《Journal of Logic, Language and Information》2008,17(4):391-415
In this paper we explore differences in use of the so-called ‘logical’ elements of language such as quantifiers and conditionals,
and use this to explain differences in performance in reasoning tasks across subject groups with different educational backgrounds.
It is argued that quantified sentences are difficult natural bases for reasoning, and hence more prone to elicit variation
in reasoning behaviour, because they are chiefly used with a pre-determined domain in everyday speech. By contrast, it is
argued that conditional sentences form natural premises because of the function they serve in everyday speech. Implications
of this for the role of logic in modelling human reasoning behaviour are briefly considered. 相似文献
998.
Ting Wang Jochem Vonk Benedikt Kratz Paul Grefen 《Distributed and Parallel Databases》2008,23(3):235-270
Transactions have been around since the Seventies to provide reliable information processing in automated information systems.
Originally developed for simple ‘debit-credit’ style database operations in centralized systems, they have moved into much
more complex application domains including aspects like distribution, process-orientation and loose coupling. The amount of
published research work on transactions is huge and a number of overview papers and books already exist. A concise historic
analysis providing an overview of the various phases of development of transaction models and mechanisms in the context of
growing complexity of application domains is still missing, however. To fill this gap, this paper presents a historic overview
of transaction models organized in several ‘transaction management eras’, thereby investigating numerous transaction models
ranging from the classical flat transactions, via advanced and workflow transactions to the Web Services and Grid transaction
models. The key concepts and techniques with respect to transaction management are investigated. Placing well-known research
efforts in historical perspective reveals specific trends and developments in the area of transaction management. As such,
this paper provides a comprehensive, structured overview of developments in the area. 相似文献
999.
John Stachurski 《Computational Economics》2008,31(2):141-160
This paper studies fitted value iteration for continuous state numerical dynamic programming using nonexpansive function approximators.
A number of approximation schemes are discussed. The main contribution is to provide error bounds for approximate optimal
policies generated by the value iteration algorithm.
相似文献
1000.
Multi-core CPUs,Clusters, and Grid Computing: A Tutorial 总被引:1,自引:0,他引:1
The nature of computing is changing and it poses both challenges and opportunities for economists. Instead of increasing clock
speed, future microprocessors will have “multi-cores” with separate execution units. “Threads” or other multi-processing techniques
that are rarely used today are required to take full advantage of them. Beyond one machine, it has become easy to harness
multiple computers to work in clusters. Besides dedicated clusters, they can be made up of unused lab computers or even your
colleagues’ machines. Finally, grids of computers spanning the Internet are now becoming a reality. 相似文献