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61.
We present our machine learning system, that uses inductive logic programming techniques to learn how to identify transmembrane
domains from amino acid sequences. Our system facilitates the use of operators such as ‘contains’, that act on entire sequences,
rather than on individual elements of a sequence. The prediction accuracy of our new system is around 93%, and this compares
favourably with earlier results.
This work was carried out with the support of a research grant from ISIS, Fujitsu Laboratories. 相似文献
62.
This paper demonstrates how the problem of tracking targets, which appear as either straight or curved lines in two-dimensional display images (or data images) can be formulated in terms of a directed weighted graph model and how dynamic programming techniques can be efficiently applied to reach an optimal or sub-optimal solution. In general, track detection algorithms providing optimal solutions have good detective ability, but most of them suffer from the inability to detect discontinuous lines or to resolve efficiently pairs of crossing lines. A sub-optimal solution is provided that efficiently overcomes these weaknesses. We focus on modeling the track detection problem in terms of a graph, formulating fast sequential/parallel sub-optimal track detection algorithms and testing them on simulated data in order to show their detective ability. Moreover, we specify the conditions under which sub-optimal algorithms can perform at least as well as their corresponding optimal algorithms. This is significant for the track detection problem where fast, accurate and real-time detection is considered a necessity. 相似文献
63.
This paper formulates the pickup and delivery problem, also known as the dial-a-ride problem, as an integer program. Its polyhedral structure is explored and four classes of valid inequalities developed. The results of a branch-and-cut algorithm based on these constraints are presented. 相似文献
64.
在基于单片机的智能化重力加速度测试仪中采用C语言编程简化了程序设计任务,对于汇编语言难于处理的浮点数运算及汉字打印输出可通过C语言编译器的内部库函数调用实现,介绍了一种专为8051系列单片机设计的C语言编译器Frankilin C51,它具有代码优化功能,能产生极高效率的机器码,并且提供了丰富的内部函数库。描述了C51函数库所支持的IEEE标准浮点数的内存格式以及采用sprintf()函数处理包括 相似文献
65.
J. Dingel 《Formal Aspects of Computing》2002,14(2):123-197
Parallel computers have not yet had the expected impact on mainstream computing. Parallelism adds a level of complexity to
the programming task that makes it very error-prone. Moreover, a large variety of very different parallel architectures exists.
Porting an implementation from one machine to another may require substantial changes. This paper addresses some of these
problems by developing a formal basis for the design of parallel programs in the form of a refinement calculus. The calculus
allows the stepwise formal derivation of an abstract, low-level implementation from a trusted, high-level specification. The
calculus thus helps structuring and documenting the development process. Portability is increased, because the introduction
of a machine-dependent feature can be located in the refinement tree. Development efforts above this point in the tree are
independent of that feature and are thus reusable. Moreover, the discovery of new, possibly more efficient solutions is facilitated.
Last but not least, programs are correct by construction, which obviates the need for difficult debugging. Our programming/specification
notation supports fair parallelism, shared-variable and message-passing concurrency, local variables and channels. The calculus
rests on a compositional trace semantics that treats shared-variable and message-passing concurrency uniformly. The refinement
relation combines a context-sensitive notion of trace inclusion and assumption-commitment reasoning to achieve compositionality.
The calculus straddles both concurrency paradigms, that is, a shared-variable program can be refined into a distributed, message-passing
program and vice versa.
Received July 2001 / Accepted in revised form May 2002 相似文献
66.
最小生成树的高效异步并行算法 总被引:1,自引:0,他引:1
在MIMD-SM并行计算模型上,本文给出了时间复杂性为O(n(n/p+logp))的最小生成树的异步并行算法,其中n,p(1≤p≤n)分别表示图的顶点数和处理机的个数。 相似文献
67.
朱江红 《导弹与航天运载技术》1995,(4):28-40
球轴承作为重要的支承部件,广泛用于惯性仪表之中。通过对球轴承的变形理论进行分析,建立了轴承的总体平衡方程,并将轴承的变形问题转化为数学上求解目标函数的极小值问题,用POWELL优化方法编制了能不同排列形向心推力球轴承在不同预载下及在径向、轴向联合工作负荷作用下的变形、接触应力进行计算的FORTRAN程序,解决了手工计算解决了不的问题,从而为分析不同结构参数和载荷对球轴承刚度的影响提供了重要手段,为 相似文献
68.
王厚峰 《计算机研究与发展》1994,31(6):14-18
在对英文排版时,我们既应考虑单词之间的间隔,以便清晰可读,又应考虑节省版面,以便降低费用,本文通过详细地讨论两种算法可以解决这一矛盾。 相似文献
69.
Let us consider n data measurements of a univariate process that have been altered by random errors. We assume that an underlying model function has a substantially smaller number of turning points than the observed ones. We propose algorithms that make least the sum of the moduli of the errors by requiring k monotonic sections, alternately increasing and decreasing, in the sequence of the smoothed values. The main difficulty in this calculation is that the optimal positions of the joins of the monotonic sections have to be found automatically among so many combinations that it is impossible to test each one separately. Moreover, the calculation seems to be very intractable to general optimization techniques because O(nk ) local minima can occur. It is shown that dynamic programming can be used for separating the data into optimal disjoint sections of adjacent data, where each section requires a single L1 monotonic calculation. This procedure is highly efficient, requiring at most O(kn2 ) computer operations and O(n) best L1 monotonic calculations to subranges of data for a global minimum. 相似文献
70.
Brian J. Ross 《Formal Aspects of Computing》1997,9(3):331-348
Imperative programs can be inverted directly from their forward-directed program code with the use of logical inference. The relational semantics of imperative computations treats programs as logical relations over the observable state of the environment, which is taken to be the state of the variables in memory. Program relations denote both forward and backward computations, and the direction of the computation depends upon the instantiation pattern of arguments in the relation. This view of inversion has practical applications when the relational semantics is treated as a logic program. Depending on the logic programming inference scheme used, execution of this relational program can compute the inverse of the imperative program. A number of nontrivial imperative computations can be inverted with minimal logic programming tools. 相似文献