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31.
Only a few studies that have examined the effects of participation on an individual's goal acceptance and performance have been conducted within a cross-cultural context. In the present study, we tested for the contingency between the effectiveness of goal-setting strategies and cultural values. We examined three goal-setting strategies within three different cultural groups—assigned goals, goals participatively set by a group representative and the experimenter, and goals participatively set by a group. The three cultural groups studied were U.S. students (n?=?60), individualistic and having a high power distance; Israeli students from urban areas (n?=?60), collectivistic and having a low power distance; and Israeli students from kibbutzim (n?=?60), highly collectivistic and having a low power distance. Results indicated that participative strategies led to higher levels of goal acceptance and performance than the assigned strategy. Culture did not moderate the effect of goal-setting strategies on goal acceptance, but it appeared to moderate the strategy on performance for extremely difficult goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
32.
Schizophrenic and control participants received 2 blocks of trials in each experiment. In 1 block they were exposed to regular priming trials (doctor–nurse), and in another block a nonlexical probe was presented at prime onset for 40 ms. Regardless of stimulus onset asynchrony (SOA), the schizophrenic patients showed hyperpriming when no distractor was present. Paying attention to the distracting stimulus reduced priming in the patient group irrespective of SOA. Under certain situations, the reduction in priming appeared even when participants were asked to ignore the distracting stimulus. Thus, even a nonsemantic distractor may be detrimental to schizophrenic patients' language processing. That SOA did not modulate the reduction in priming effect is consistent with the suggestion that attentional resources are required even with short prime–target intervals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
33.
The paper studies broadcasting in radio networks whose stations are represented by points in the Euclidean plane (each station knows its own coordinates). In any given time step, a station can either receive or transmit. A message transmitted from station v is delivered to every station u at distance at most 1 from v, but u successfully hears the message if and only if v is the only station at distance at most 1 from u that transmitted in this time step. A designated source station has a message that should be disseminated throughout the network. All stations other than the source are initially idle and wake up upon the first time they hear the source message. It is shown in [17] that the time complexity of deterministic broadcasting algorithms depends on two parameters of the network, namely, its diameter (in hops) D and a lower bound d on the Euclidean distance between any two stations. The inverse of d is called the granularity of the network, denoted by g. Specifically, the authors of [17] present a deterministic broadcasting algorithm that works in time O (Dg) and prove that every broadcasting algorithm requires \(\varOmega \left( D \sqrt{g} \right) \) time. In this paper, we distinguish between the arbitrary deployment setting, originally studied in [17], in which stations can be placed everywhere in the plane, and the new grid deployment setting, in which stations are only allowed to be placed on a d-spaced grid. Does the latter (more restricted) setting provide any speedup in broadcasting time complexity? Although the O (Dg) broadcasting algorithm of [17] works under the (original) arbitrary deployment setting, it turns out that the \(\varOmega \left( D \sqrt{g} \right) \) lower bound remains valid under the grid deployment setting. Still, the above question is left unanswered. The current paper answers this question affirmatively by presenting a provable separation between the two deployment settings. We establish a tight lower bound on the time complexity of deterministic broadcasting algorithms under the arbitrary deployment setting proving that broadcasting cannot be completed in less than \(\varOmega (D g)\) time. For the grid deployment setting, we develop a deterministic broadcasting algorithm that runs in time \(O \left( D g^{5 / 6} \log g \right) \), thus breaking the linear dependency on g.  相似文献   
34.
Forest parameters, such as mean diameter at breast height (DBH), mean stand height (H) or volume per hectare (V), are imperative for forest resources assessment. Traditional forest inventory that is usually based on fieldwork is often difficult, time-consuming, and expensive to conduct over large areas. Therefore, estimating forest parameters in large areas using a traditional inventory approach combined with satellite data analysis can improve the spatial estimates of forest inventory data, and hence be useful for sustainable forest management and natural resources assessment. However, extracting practical information from satellite imagery for such purpose is a challenging task mainly because of insufficient knowledge linking forest inventory data to satellite spectral response. Here, we present the use of a cost-free Landsat-7 Enhanced Thematic Mapper Plus (ETM+) in order to explore whether it is possible to combine all available optical bands from a specific sensor for improving forest parameter spatial estimates, based on fieldwork at Lahav and Kramim Forests, in the Israeli Northern Negev. A generic strategy, based on morphological structuring element, convex hall and spectral band linear combination algorithms, was developed in order to extract the mathematical dependencies between the forest inventory measurements and linear combination sets of Landsat-7 ETM+ spectral bands, which yields the highest possible correlation with the forest inventory measured data. Using the mathematical dependency functions, we then convert the entire Landsat-7 ETM+ scenes into forest inventory parameter values with sufficient accuracy and tolerance errors needed for sustainable forest management. The root mean square error obtained between the measured and the estimated values for Lahav Forest are 0.70 cm, 0.29 m, and 1.48 m3 ha?1 for the mean DBH, H, and V, respectively, and for Kramim forest are 0.61 cm, 0.70 m, and 6.31 m3 ha?1, respectively. Furthermore, the suggested strategy could also be applied with other satellites data sources.  相似文献   
35.
This paper describes a thermal multi-scale formulation for composite materials based on a mechanical homogenization approach. The presented formulation evaluates the effective macroscopic thermal conductivity of the composite materials and also the microscopic heat flux field by scaling down to the micro-scale level. The effective thermal conductivity of the composite materials was calculated by applying the homogenization theory over the unit cell. The uniqueness of the presented multi-scale analysis related to the elastic problems solved at the microscopic scale (unit cell). This method has the advantage of applying periodic boundary conditions and uniform macroscopic temperature gradient over the unit cell. The proposed thermal multi-scale analysis was verified and its efficiency was demonstrated on large scale problem.  相似文献   
36.
A literature review is presented that identifies a number of areas where procedures for the engineering design of bored installations in soil using horizontal directional drilling (HDD) can be improved through a more realistic consideration of drilling fluid drag effects and skin friction coefficients. The current HDD practice of calculating annular frictional pressure loss caused by drilling fluid drag based on the assumption of concentric annular flow of a Bingham plastic fluid is demonstrated to be overly conservative. Consequently, critical design parameters, such as depth of cover, which affects crossing length, and drilling equipment size, which is selected based on anticipated pulling load, cannot be optimized. This can result in overly conservative design and unnecessary construction costs. Parameter values currently employed in HDD pulling load prediction are challenged suggesting that the viscous shear of drilling fluid is significantly less than typically quoted and that the friction coefficients often employed are not representative of all skin friction effects in HDD. A new real-time monitoring cell for large-scale HDD is described that can be used to optimize installations and to assess and update current prediction models.  相似文献   
37.
Consider the optimum strategy for using channel state (“side”) information in transmission over a modulo-additive noise channel, with state-dependent noise, where the receiver does not have access to the side information (SI). Previous work showed that capacity-wise, the optimum transmitter shifts each code letter by a “prediction” of the noise sample based on the SI. We show that this structure achieves also the random-coding error exponent, and, therefore, is optimum at some range of rates below capacity. Specifically, the optimum transmitter predictor minimizes the Renyi entropy of the prediction error; the Renyi order depends on the rate, and goes to one (corresponding to Shannon entropy) for rates close to capacity. In contrast, it is shown that this “prediction strategy” may not be optimal at low transmission rates  相似文献   
38.
In this paper, we present an empirical study of iterative least squares minimization of the Hamilton-Jacobi-Bellman (HJB) residual with a neural network (NN) approximation of the value function. Although the nonlinearities in the optimal control problem and NN approximator preclude theoretical guarantees and raise concerns of numerical instabilities, we present two simple methods for promoting convergence, the effectiveness of which is presented in a series of experiments. The first method involves the gradual increase of the horizon time scale, with a corresponding gradual increase in value function complexity. The second method involves the assumption of stochastic dynamics which introduces a regularizing second derivative term to the HJB equation. A gradual reduction of this term provides further stabilization of the convergence. We demonstrate the solution of several problems, including the 4-D inverted-pendulum system with bounded control. Our approach requires no initial stabilizing policy or any restrictive assumptions on the plant or cost function, only knowledge of the plant dynamics. In the Appendix, we provide the equations for first- and second-order differential backpropagation.  相似文献   
39.
Communities that surround an operating construction site often find themselves subjected to negative impacts such as annoyances and economic losses. The latter often called “social costs”, refer to the monetary equivalent of consumed resources, loss of income and loss of enjoyment experienced by parties not engaged in the contractual agreement, solely due to a construction process. Social costs take many forms including loss of revenue, productivity and time, consumption of non-renewable resources and accelerated deterioration of secondary roads.Social costs, while widely acknowledged, are rarely considered in the design, planning or bid evaluation phases of construction projects in North America. This is attributed to the difficulty associated with quantifying social costs using standard estimating methods and the fact that these costs are borne by the community rather than the contractual parties. This paper outlines 22 sources of social costs associated with construction projects in urban environments. The concept of ‘social indicators' is introduced as a mean to link adverse impacts generated by construction activities and valuation methods. Thereafter, seven methodologies developed in the fields of economics and actuary are presented and their suitability for quantifying specific classes of social costs associated with construction projects are investigated. The capacity of current bid evaluation methods to account for social costs is also examined. It is concluded that a methodical approach for the incorporation of social costs in the bid evaluation process will be a key step towards a more sustainable-oriented construction industry. A generic framework for the development of such an approach is presented. Finally, the concept of developing a standard reference document to estimate social costs is examined and a sample format proposed.  相似文献   
40.
We describe here a bacterial sensor for electrochemical detection of toxic chemicals. The sensor constitutes recombinant bacteria harboring plasmids encoding the fabA and fabR genes and has high-resolution amperometric response to membrane-damaging chemicals. For example, it can detect phenol at concentrations ranging between 1.6 and 16 ppm within 20 min. The high sensitivity is achieved by using the fabA promoter fused to a reporter gene-encoded beta-galactosidase on a low copy number plasmid, under the control of the FabR repressor. The use of electrochemical whole cell sensors enables sensitive, fast, easy to operate, and cost-effective detection of water toxicity threats.  相似文献   
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