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排序方式: 共有360条查询结果,搜索用时 15 毫秒
91.
This paper presents the results of a case study on generating test cases for a fragment of the smart card GSM 11‐11 standard. The generation method is based on an original approach using the B notation and techniques of constraint logic programming with sets. The GSM 11‐11 technical specifications were formalized with the B notation. From this B specification, a system of constraints was derived, equivalent to this formal model. Using a set constraint solver, boundary states were computed and test cases were obtained by traversing the constrained reachability graph of the specifications. The purpose of this project was to evaluate the contribution of this testing environment, called B ‐TESTING ‐TOOLS , in an industrial process on a real life‐size application, by comparing the generated test sequences with the already used and high‐quality manually‐designed tests. This comparison enabled us to validate our approach and showed its effectiveness in the validation process of critical applications: the case study gives a wide coverage (about 85%) of the generated tests compared to the pre‐existing tests and a saving of 30% in test design time. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
92.
93.
Is biological treatment a viable alternative for micropollutant removal in drinking water treatment processes? 总被引:1,自引:0,他引:1
Jessica Benner Damian E. Helbling Hans-Peter E. Kohler Janneke Wittebol Elena Kaiser Carsten Prasse Thomas A. Ternes Christian N. Albers Jens Aamand Benjamin Horemans Dirk Springael Eddy Walravens Nico Boon 《Water research》2013
In western societies, clean and safe drinking water is often taken for granted, but there are threats to drinking water resources that should not be underestimated. Contamination of drinking water sources by anthropogenic chemicals is one threat that is particularly widespread in industrialized nations. Recently, a significant amount of attention has been given to the occurrence of micropollutants in the urban water cycle. Micropollutants are bioactive and/or persistent chemicals originating from diverse sources that are frequently detected in water resources in the pg/L to μg/L range. The aim of this review is to critically evaluate the viability of biological treatment processes as a means to remove micropollutants from drinking water resources. We first place the micropollutant problem in context by providing a comprehensive summary of the reported occurrence of micropollutants in raw water used directly for drinking water production and in finished drinking water. We then present a critical discussion on conventional and advanced drinking water treatment processes and their contribution to micropollutant removal. Finally, we propose biological treatment and bioaugmentation as a potential targeted, cost-effective, and sustainable alternative to existing processes while critically examining the technical limitations and scientific challenges that need to be addressed prior to implementation. This review will serve as a valuable source of data and literature for water utilities, water researchers, policy makers, and environmental consultants. Meanwhile this review will open the door to meaningful discussion on the feasibility and application of biological treatment and bioaugmentation in drinking water treatment processes to protect the public from exposure to micropollutants. 相似文献
94.
Rob J. Aerts Andries Stoker Maarten Beishuizen Ineke Jaarsma Mieke Van De Heuvel Eddy Van Der Meijden Rob Verpoorte 《Journal of chemical ecology》1992,18(11):1955-1964
YoungCinchona ledgeriana plants contain two types of alkaloid: indole alkaloids in the leaves and quinoline alkaloids in the root. FromCinchona leaves, a crude alkaloid extract was made, containing the cinchophylline type of indole alkaloids and a small amount of 5-methoxytryptamine. The leaf alkaloid extract exerted a strong detrimental effect on the growth of larvae of the polyphagous beet armyworm,Spodoptera exigua (Lepidoptera). Feeding of larvae on an artificial diet containing the leaf alkaloids at the same concentrations as those found in the plant resulted in significant growth reduction, retardation in development, and mortality of the larvae. Cinchophyllines are composed of 5-methoxytryptamine coupled to a corynantheal unit. When incorporated into the artificial diet, 5-methoxytryptamine alone had no effect on the 5.exigua larvae. Corynantheal, however, had a strong detrimental effect on growth of the larvae, its effect being comparable to that of the leaf alkaloid extract. In contrast to the indole-type leaf alkaloids, the quinolinetypeCinchona root alkaloids did not affect growth and development of the larvae. These results suggest that the indole-type alkaloids, which inCinchona plants are present at the highest concentrations in the young, vulnerable leaflets, are involved in the chemical defense of the plant against herbivorous insects. 相似文献
95.
Although workaholism has been hypothesized to have an effect on interpersonal relationships, few studies have obtained data from other individuals in a focal person's network. The present exploratory study examined level of agreement in both workaholism components proposed by Spence and Robbins (see record 1992-18384-001; work involvement, feeling driven to work, work enjoyment) and hours worked per week between 62 women and men in professional and managerial jobs and a self-nominated coworker. Data were collected using anonymously completed questionnaires. There was considerable agreement between the two individuals on levels of the three workaholism components and hours worked per week. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
96.
97.
Karel Verscheure Mieke Campforts Frederik Verhaeghe Eddy Boydens Bart Blanpain Patrick Wollants Maurits Van Camp 《Metallurgical and Materials Transactions B》2006,37(6):929-940
Furnace protection by water-cooled freeze linings becomes increasingly important as the metal producing industry attempts
to achieve higher process intensities. Systematic investigations of the growth and the resulting microstructure and compositional
profile of freeze linings are necessary to understand the behavior of freeze linings, their relation with the industrial process,
and their interaction with the wall cooling system. We have developed a technique based on the submergence of a water-cooled
probe into a liquid slag bath. Freeze linings of two industrial nonferrous slags have been produced using this technique and
their growth, microstructural, and compositional profiles as a function of submergence time were determined. Thermodynamic
equilibrium for the investigated slag systems was calculated and compared with the observed microstructures. The freeze linings
form in approximately 15 minutes. Close to the water cooling, the freeze linings are predominantly amorphous in structure.
With increasing distance from the water cooling, the proportion of crystalline phases increases and bath material is entrapped
in the microstructure. Cellular crystals are observed close to the bath. The freeze linings exhibit an approximate homogeneous
composition. The results demonstrate that the technique is a successful tool in obtaining information on the growth, microstructure,
and composition of freeze linings in industrial water-cooled furnaces. 相似文献
98.
In this paper, we study and compare grid and global computing systems and outline the benefits of having a hybrid system called DIRAC. To evaluate the DIRAC scheduling for high throughput computing, a new model is presented and a simulator was developed for many clusters of heterogeneous nodes belonging to a local network. These clusters are assumed to be connected to each other through a global network and each cluster is managed via a local scheduler which is shared by many users. We validate our simulator by comparing the experimental and analytical results of a M/M/4 queuing system. Next, we do the comparison with a real batch system and we obtain an average error of 10.5% for the response time and 12% for the makespan. We conclude that the simulator is realistic and well describes the behaviour of a large-scale system. Thus we can study the scheduling of our system called DIRAC in a high throughput context. We justify our decentralized, adaptive and opportunistic approach in comparison to a centralized approach in such a context. 相似文献
99.
Van der Borght Karin; Havekes Robbert; Bos Thomas; Eggen Bart J. L.; Van der Zee Eddy A. 《Canadian Metallurgical Quarterly》2007,121(2):324
Enhanced physical activity is associated with improvements in cognitive function in rodents as well as in humans. The authors examined in detail which aspects of learning and memory are influenced by exercise, using a spatial Y-maze test combined with a 14-day exercise paradigm at different stages of learning. The authors show that 14 days of wheel running promotes memory acquisition, memory retention, and reversal learning. The exercise paradigm that was employed also significantly increased the number of maturing neurons, suggesting that an increase in neurogenesis underlies the positive effects of exercise on Y-maze performance. Finally, the authors show that memory acquisition in itself does not have a major impact on the number of immature neurons. However, memory retention testing and reversal learning both cause a significant reduction in the number of doublecortin and Ser133- phosphorylated pCREB-positive cells, indicating that a decrease in neurogenesis might be a prerequisite for optimal memory retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Zeng EY Tsukada D Diehl DW Peng J Schiff K Noblet JA Maruya KA 《Environmental science & technology》2005,39(21):8170-8176
A large-scale survey on the area and depth stratified distribution of dichlorodiphenyltrichloroethane (DDT; mainly p,p'- and o,p'-dichlorodiphenyldichloroethylene (DDE)) contamination in the water column of the Southern California Bight (SCB) was conducted in 2003-2004 using a solid-phase microextraction-based sampling technique. Dissolved-phase DDEs were clearly widespread, with the central SCB containing the highest levels, and the Palos Verdes Shelf sediments have remained the dominant source of DDT compounds to the SCB. The p,p'- and o,p'-DDE concentrations ranged from < 0.073 to 2.6 ng/L and from < 0.043 to 0.26 ng/L, respectively, clearly elevated with respect to measured values from across the globe. DDEs were hypothesized to have been transported from the historically contaminated zone on the Palos Verdes Shelf to other areas via a repeated process of sediment resuspension/deposition and short-range advection. Total mass inventories were estimated at 14 and 0.86 kg for p,p'- and o,p'-DDE, respectively, for the sampled area, resulting in p,p'- and o,p'-DDE mass inventories for the entire SCB of 230 and 14 kg, respectively. Furthermore, total fluxes of p,p'-DDE were estimated to be in the range of 0.8 to 2.3 metric tons per year. These results suggest that the SCB has been and continues to be a significant source of DDT contamination to the global oceans. 相似文献