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951.
952.
一种基于C#的企业管理系统的实现 总被引:5,自引:0,他引:5
以某企业的管理系统为背景,概述了在.NET平台上采用C# 语言快速构建企业应用系统的过程,并简要介绍了Microsoft.NET平台和C#语言的特点。 相似文献
953.
954.
Starting from the idea of determinism in membrane systems, we introduce a language generating device consisting of morphisms
placed in the nodes of a tree. Initial strings are given in the leaves; by iteratively applying the morphisms to them, we
produce new strings, which are collected in the root of the tree. Such a device is called a tree-system of morphisms (in short, a T system). We investigate here the power of T systems, both in the extended (a terminal alphabet is considered
and only strings over it are accepted) and non-extended case, mainly in comparison with classes of languages in Lindenmayer
hierarchy.
Received: 8 February 2001 / 18 September 2001 相似文献
955.
A distributed system is said to be fault‐tolerant if it is able to provide important services despite partial failures of the computers or software objects in the system. These systems are needed to support applications such as remote access and control, virtual mobile offices and wide area collaborative systems where there are chances of failures in the network and software objects. Fault‐tolerance is usually achieved by replicating the objects in the system. Traditional distributed applications constructed using Java RMI (remote method invocation) are not fault‐tolerant because of the lack of support of object replication. The objective of the present work is to design a remote method invocation that supports server object replication. To provide a fault‐tolerant service to the remote client objects, server objects are actively replicated. The problems associated with the method invocation in the context of active server object replication are presented and solutions are discussed and implemented. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
956.
We present a shared memory algorithm that allows a set of f+1 processes to wait-free “simulate” a larger system of n processes, that may also exhibit up to f stopping failures.
Applying this simulation algorithm to the k-set-agreement problem enables conversion of an arbitrary k-fault-tolerant{\it n}-process solution for the k-set-agreement problem into a wait-free k+1-process solution for the same problem. Since the k+1-processk-set-agreement problem has been shown to have no wait-free solution [5,18,26], this transformation implies that there is no
k-fault-tolerant solution to the n-process k-set-agreement problem, for any n.
More generally, the algorithm satisfies the requirements of a fault-tolerant distributed simulation.\/ The distributed simulation implements a notion of fault-tolerant reducibility\/ between decision problems. This paper defines these notions and gives examples of their application to fundamental distributed
computing problems.
The algorithm is presented and verified in terms of I/O automata. The presentation has a great deal of interesting modularity,
expressed by I/O automaton composition and both forward and backward simulation relations. Composition is used to include
a safe agreement\/ module as a subroutine. Forward and backward simulation relations are used to view the algorithm as implementing a multi-try snapshot\/ strategy.
The main algorithm works in snapshot shared memory systems; a simple modification of the algorithm that works in read/write
shared memory systems is also presented.
Received: February 2001 / Accepted: February 2001 相似文献
957.
Recently, High Performance Computing (HPC) platforms have been employed to realize many computationally demanding applications
in signal and image processing. These applications require real-time performance constraints to be met. These constraints
include latency as well as throughput. In order to meet these performance requirements, efficient parallel algorithms are
needed. These algorithms must be engineered to exploit the computational characteristics of such applications.
In this paper we present a methodology for mapping a class of adaptive signal processing applications onto HPC platforms
such that the throughput performance is optimized. We first define a new task model using the salient computational characteristics
of a class of adaptive signal processing applications. Based on this task model, we propose a new execution model. In the
earlier linear pipelined execution model, the task mapping choices were restricted. The new model permits flexible task mapping
choices, leading to improved throughput performance compared with the previous model. Using the new model, a three-step task
mapping methodology is developed. It consists of (1) a data remapping step, (2) a coarse resource allocation step, and (3)
a fine performance tuning step. The methodology is demonstrated by designing parallel algorithms for modern radar and sonar
signal processing applications. These are implemented on IBM SP2 and Cray T3E, state-of-the-art HPC platforms, to show the
effectiveness of our approach. Experimental results show significant performance improvement over those obtained by previous
approaches. Our code is written using C and the Message Passing Interface (MPI). Thus, it is portable across various HPC platforms.
Received April 8, 1998; revised February 2, 1999. 相似文献
958.
By transforming the personal computer into a communication appliance, the Internet has initiated the true home computing revolution. As a result, Computer Mediated Communication (CMC) technologies are increasingly used in domestic settings, and are changing the way people keep in touch with their relatives and friends. This article first looks at how CMC tools are currently used in the home, and points at some of their benefits and limitations. Most of these tools supportexplicit interpersonal communication, by providing a new medium for sustaining conversations. The need for tools supportingimplicit interaction between users, in more natural and effottless ways, is then argued for. The idea of affective awareness is introduced as a general sense of being in touch with one's family and friends. Finally, the KAN-G framework, which enables affective awareness through the exchange of digital photographs, is described. Various components, which make the capture, distribution, observation and annotation of snapshots easy and effortless, are discussed. 相似文献
959.
李晓飞 《长春工业大学学报(自然科学版)》2013,(6):736-740
借助分割数据技术优化了经典的Apriori算法,实现了对候选项集的分组统计。给出了优化Apriori算法的MapReduce编程实现模型,达到了Apriori算法并行化的目的。实验结果表明,该算法能够大量减少键/值对的产生,提高了算法的效率,并且随着挖掘频繁项目集节点数的增加,算法的加速比成线性提高。 相似文献
960.
针对当前运行于不可预测开放环境下的嵌入式多使命复杂关键型系统,需要减少运行成本和处理不可预测工作负载情况的问题,文章提出一种混合关键度驱动的非对称式过载保护最小空闲调度策略。系统过载时,为共享同一处理器的不同关键度任务提供非对称式保护,禁止低关键度任务干扰高关键度任务,完全避免了传统的"关键度反转"问题。在恢复暂时阻塞的不同关键度任务时,在速率单调调度的基础上,引入关键度主导的截止期驱动动态调度策略,可使潜在处理器利用率达到100%。实验结果表明,这种新算法的综合性能优于当前已有的混合关键度任务调度算法。 相似文献