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排序方式: 共有264条查询结果,搜索用时 15 毫秒
1.
Loschky Lester C.; Sethi Amit; Simons Daniel J.; Pydimarri Tejaswi N.; Ochs Daniel; Corbeille Jeremy L. 《Canadian Metallurgical Quarterly》2007,33(6):1431
People can recognize the meaning or gist of a scene from a single glance, and a few recent studies have begun to examine the sorts of information that contribute to scene gist recognition. The authors of the present study used visual masking coupled with image manipulations (randomizing phase while maintaining the Fourier amplitude spectrum; random image structure evolution [RISE]; J. Sadr & P. Sinha, 2004) to explore whether and when unlocalized Fourier amplitude information contributes to gist perception. In 4 experiments, the authors found that differences between scene categories in the Fourier amplitude spectrum are insufficient for gist recognition or gist masking. Whereas the global 1/f spatial frequency amplitude spectra of scenes plays a role in gist masking, local phase information is necessary for gist recognition and for the strongest gist masking. Moreover, the ability to recognize the gist of a target image was influenced by mask recognizability, suggesting that conceptual masking occurs even at the earliest stages of scene processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Finding trajectories of feature points in a monocular image sequence 总被引:16,自引:0,他引:16
Identifying the same physical point in more than one image, the correspondence problem, is vital in motion analysis. Most research for establishing correspondence uses only two frames of a sequence to solve this problem. By using a sequence of frames, it is possible to exploit the fact that due to inertia the motion of an object cannot change instantaneously. By using smoothness of motion, it is possible to solve the correspondence problem for arbitrary motion of several nonrigid objects in a scene. We formulate the correspondence problem as an optimization problem and propose an iterative algorithm to find trajectories of points in a monocular image sequence. A modified form of this algorithm is useful in case of occlusion also. We demonstrate the efficacy of this approach considering synthetic, laboratory, and real scenes. 相似文献
3.
In this paper, we consider a dynamic supply chain where a manufacturer produces and distributes a featured product through an exclusive retailer to end consumers. The manufacturer decides the product quality and wholesale price, while the retailer sets the retail price in the presence of a revenue-sharing contract and consumers’ reference quality effects. The objective of this study is to investigate the impacts of myopic behaviour regarding the reference quality on the product quality and pricing strategies and profits of both members. Our results suggest that the manufacturer’s myopia leads to a higher quality, higher price strategy and a higher quality–price ratio which benefits consumers. Meanwhile, relative to the far-sighted behaviour, myopia results in a more quality-sensitive but less price-sensitive market demand. What’s more, we find that the manufacturer is apt to act in a far-sighted way, but the retailer isn’t always willing to cooperate with a far-sighted manufacturer. Taking myopic strategies for both members is likely to gain a high profit of the whole supply chain for a relatively high marginal contribution of product quality on demand and a relatively low revenue-sharing proportion. 相似文献
4.
H. Neil Geismar Suresh P. Sethi Jeffrey B. Sidney Chelliah Sriskandarajah 《International Journal of Flexible Manufacturing Systems》2005,17(1):5-21
Flexible robotic cells combine the capabilities of robotic flow shops with those of flexible manufacturing systems. In an
m-machine flexible cell, each part visits each machine in the same order. However, the m operations can be performed in any order, and each machine can be configured to perform any operation. We derive the maximum
percentage increase in throughput that can be achieved by changing the assignment of operations to machines and then keeping
that assignment constant throughout a lot's processing. We find that no increase can be gained in two-machine cells, and that
the gain in three- and four-machine cells each is at most 14
%. 相似文献
5.
In this paper, a new classifier design methodology, confidence-based classifier design, is proposed to design classifiers with controlled confidence. This methodology is under the guidance of two optimal classification theories, a new classification theory for designing optimal classifiers with controlled error rates and the C.K. Chow's optimal classification theory for designing optimal classifiers with controlled conditional error. The new methodology also takes advantage of the current well-developed classifier's probability preserving and ordering properties. It calibrates the output scores of current classifiers to the conditional error or error rates. Thus, it can either classify input samples or reject them according to the output scores of classifiers. It can achieve some reasonable performance even though it is not an optimal solution. An example is presented to implement the new methodology using support vector machines (SVMs). The empirical cumulative density function method is used to estimate error rates from the output scores of a trained SVM. Furthermore, a new dynamic bin width allocation method is proposed to estimate sample conditional error and this method adapts to the underlying probabilities. The experimental results clearly demonstrate the efficacy of the suggested classifier design methodology. 相似文献
6.
Ravi Sethi 《Software》1984,14(3):291-297
Some parser generators allow the user to attach actions, consisting of executable code, to syntax rules. Actions are usually in the local programming language, so they are simply copied into the generated parser. However, we show two situations in which it is convenient to allow actions to be in a different notation. A preprocessor is used to translate such notations into the local programming language. A preprocessor must know where to find actions and how to translate them. We show how these two activities can be programmed separately. Often, the user only has to worry about the second part: once the parser generator is known, the placement of the actions is known as well, so routines for finding actions can be separately compiled and linked in. Examples in the paper are based on the parser generator Yacc, but the approach is not limited to Yacc, or even to parser generators. Certain compositions of syntax-directed translations can be implemented by preprocessing actions. 相似文献
7.
The effect of anodic oxide films on the mechanical behavior of single crystals of niobium and tantalum was investigated. Near room temperature, oxide films cause an increase in strength, in the manner generally observed for face-centered cubic crystals. At lower temperatures, oxide films reduce the yield stress and its temperature dependence and cause serrated flow over an appreciable range of strains. When the oxide films are removed from specimens deformed at lower temperatures, the serrations disappear during subsequent deformation, and the yield stress increases rapidly to that of the uncoated material. A model involving generation and motion of edge dislocations from the oxide-metal interface is used to explain the results. 相似文献
8.
Further investigation of the humoral immune responses of patients with sarcoma to their tumors revealed a sarcoma-associated antigen that was readily detected by complement fixation. Circulating levels of antibody to this antigen, tentatively labeled S3, rose markedly after surgical removal of the tumor. Antibody to S3, as to S1 and S2, was highly prevalent in patients with various malignant tumors other than sarcoma. 相似文献
9.
Chen Y. Sethi S.P. Zhang H. 《Automation Science and Engineering, IEEE Transactions on》2007,4(3):395-406
This paper considers a production-inventory problem in which the manufacturer participates in an energy buy-back program, which offers probabilistic opportunities with rewards for not using electricity. That is, the manufacturer will get paid for stopping production to save on electricity. The amount rewarded in a period will depend on the electricity market condition at that time. The market condition in any given period is represented by states: normal (i.e., nonpeak), peak type , peak type , and the reward amount in the period will be, and, respectively. The occurrence of each state in a period is dictated by a known probability distribution. The objective is to determine from the manufacturer's perspective, whether to take such an offer when it arises. Under a mild assumption, we show that in the normal market condition, the production decision is partly a base-stock policy, whereas under peak type condition, the manufacturer, upon accepting the offer, produces according to an policy, where. The numerical experiment demonstrates that the cost savings due to buy-backs can be substantial. It also shows that the always-participating strategy (i.e., the firm shuts down production whenever the buy-back program is activated) can perform much worse than the never-participating strategy. 相似文献
10.
Computation of approximate optimal policies in a partially observed inventory model with rain checks
Alain Bensoussan Metin Cakanyildirim Suresh P. Sethi Ruixia ShiAuthor vitae 《Automatica》2011,(8):1589-1604
This paper proposes a new methodology to solve partially observed inventory problems. Generally, these problems have infinite-dimensional states that are conditional distributions of the inventory level. Our methodology involves linearizing the state transitions via unnormalized probabilities. It then uses an appropriate functional basis to represent the state. Considering the speed and stability of computations, we choose truncated Chebyshev polynomials as the basis. We use Fast Fourier Transforms along with an appropriate discretization of inventory levels to speed up the computations. These main ideas are blended to obtain an iterative algorithm to solve a partially observed inventory model with rain checks. In this model, the inventory manager (IM) does not know the inventory level when it is positive. Otherwise, the IM fully observes it. This model provides a context to illustrate our methodology, which applies to other such models. Although this model has been studied mathematically in the literature, the use of our algorithm provides a numerical approximation of the optimal order quantities. These are compared to the orders released under a base mean-stock policy, where the IM replaces the unobserved inventory level with its mean and applies the well-known base stock policy. We show numerically that the optimal order quantity is very close to the base mean-stock order quantity, when the variance of the inventory distribution is small. When the mean of the inventory distribution is large, the optimal order quantity is more than the base mean-stock quantity, and it is the other way around when the mean is small or negative. These insights are explained via uncertainty and information effects and their interplay. We expect this interplay to show up in other partially observed inventory models. 相似文献