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ContextIn software, there are the error cases that are anticipated at specification and design time, those encountered at development and testing time, and those that were never anticipated before happening in production. Is it possible to learn from the anticipated errors during design to analyze and improve the resilience against the unanticipated ones in production?ObjectiveIn this paper, we aim at analyzing and improving how software handles unanticipated exceptions. The first objective is to set up contracts about exception handling and a way to assess them automatically. The second one is to improve the resilience capabilities of software by transforming the source code.MethodWe devise an algorithm, called short-circuit testing, which injects exceptions during test suite execution so as to simulate unanticipated errors. It is a kind of fault-injection techniques dedicated to exception-handling. This algorithm collects data that is used for verifying two formal contracts that capture two resilience properties w.r.t. exceptions: the source-independence and pure-resilience contracts. Then we propose a code modification technique, called “catch-stretching” which allows error-recovery code (of the form of catch blocks) to be more resilient.ResultsOur evaluation is performed on 9 open-source software applications and consists in analyzing 241 catch blocks executed during test suite execution. Our results show that 101/214 of them (47%) expose resilience properties as defined by our exception contracts and that 84/214 of them (39%) can be transformed to be more resilient.ConclusionOur work shows that it is possible to reason on software resilience by injecting exceptions during test suite execution. The collected information allows us to apply one source code transformation that improves the resilience against unanticipated exceptions. This works best if the test suite exercises the exceptional programming language constructs in many different scenarios. 相似文献
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异常会造成程序错误,实现完全没有异常的浮点计算软件也很艰难,因此,实现有效的异常处理方法很重要.但现有的异常处理并不针对浮点运算,并且研究重点都集中在整数溢出错误上,而浮点类型运算降低了整数溢出存在的可能.针对上述现象,面向基于汇编实现的数学函数,提出了一种针对浮点运算的分段式异常处理方法.通过将异常类型映射为64位浮点数,以核心运算为中心,将异常处理过程分为3个阶段:输入参数检测(处理INV异常)、特定代码检测(处理DZE异常和INF异常)以及输出结果检测(处理FPF异常和DNO异常),并从数学运算的角度对该方法采用分段式处理的原因进行了证明.实验将该方法应用于Mlib浮点函数库,对库中600多个面向不同平台的浮点函数进行了测试.测试结果表明:该方法能够将出现浮点异常即中断的函数个数从90%降到0%.同时,实验结果验证了该方法的高效性. 相似文献
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研究基于关键资源优先的单元化“装卸、搬运、装卸” 三级作业链的调度问题. 在已知关键资源调度方案的条件下, 将两个非关键各作业级的调度问题分别转化为最小单位流问题, 并建立相应的0/1 整数规划模型求解. 为求解大规模问题, 提出三级装卸搬运的分时协调策略. 参照宁波港码头数据, 设计面向集装箱码头的仿真算例, 实验结果验证了所提出模型和策略的有效性.
相似文献25.
This paper deals with the development of effective techniques to automatically obtain the optimum management of petroleum fields aiming to increase the oil production during a given concession period of exploration. The optimization formulations of such a problem turn out to be highly multimodal, and may involve constraints. In this paper, we develop a robust particle swarm algorithm coupled with a novel adaptive constraint-handling technique to search for the global optimum of these formulations. However, this is a population-based method, which therefore requires a high number of evaluations of an objective function. Since the performance evaluation of a given management scheme requires a computationally expensive high-fidelity simulation, it is not practicable to use it directly to guide the search. In order to overcome this drawback, a Kriging surrogate model is used, which is trained offline via evaluations of a High-Fidelity simulator on a number of sample points. The optimizer then seeks the optimum of the surrogate model. 相似文献
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Jehoon Lee Romeil Sandhu Allen Tannenbaum 《Computer Vision and Image Understanding》2013,117(8):922-933
In this paper, we address the problem of 2D–3D pose estimation. Specifically, we propose an approach to jointly track a rigid object in a 2D image sequence and to estimate its pose (position and orientation) in 3D space. We revisit a joint 2D segmentation/3D pose estimation technique, and then extend the framework by incorporating a particle filter to robustly track the object in a challenging environment, and by developing an occlusion detection and handling scheme to continuously track the object in the presence of occlusions. In particular, we focus on partial occlusions that prevent the tracker from extracting an exact region properties of the object, which plays a pivotal role for region-based tracking methods in maintaining the track. To this end, a dynamical choice of how to invoke the objective functional is performed online based on the degree of dependencies between predictions and measurements of the system in accordance with the degree of occlusion and the variation of the object’s pose. This scheme provides the robustness to deal with occlusions of an obstacle with different statistical properties from that of the object of interest. Experimental results demonstrate the practical applicability and robustness of the proposed method in several challenging scenarios. 相似文献
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林桂亮 《数字社区&智能家居》2009,(9)
本文结合我院‘教育技术中心’非线性编辑系统的开发使用,比较分析了非线性编辑系统的优点,论述非线性编辑在视频制作、以及实践教学等方面的综合应用以及在应用非线性编辑系统制作中的一些问题。 相似文献
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针对随机时间序列的强不确定性和非线性特征,结合粗糙集理论和成组数据处理的神经网络技术建立了基于粗集的GMDH神经网络预测模型.同时就自然界大多数的随机时间序列数据维数较大的问题,为提高约简效率,提出了基于快速求核和集合近似质量的约简算法,并进行了仿真验证.结果表明,基于粗集的GMDH神经网络预测模型合理可行,约简算法快速有效. 相似文献