全文获取类型
收费全文 | 745篇 |
免费 | 25篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 12篇 |
综合类 | 2篇 |
化学工业 | 122篇 |
金属工艺 | 15篇 |
机械仪表 | 24篇 |
建筑科学 | 15篇 |
矿业工程 | 1篇 |
能源动力 | 71篇 |
轻工业 | 47篇 |
水利工程 | 6篇 |
石油天然气 | 8篇 |
无线电 | 104篇 |
一般工业技术 | 126篇 |
冶金工业 | 63篇 |
原子能技术 | 6篇 |
自动化技术 | 152篇 |
出版年
2023年 | 7篇 |
2022年 | 16篇 |
2021年 | 39篇 |
2020年 | 27篇 |
2019年 | 39篇 |
2018年 | 32篇 |
2017年 | 42篇 |
2016年 | 34篇 |
2015年 | 20篇 |
2014年 | 43篇 |
2013年 | 64篇 |
2012年 | 36篇 |
2011年 | 45篇 |
2010年 | 39篇 |
2009年 | 25篇 |
2008年 | 17篇 |
2007年 | 20篇 |
2006年 | 20篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 21篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 18篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有774条查询结果,搜索用时 15 毫秒
31.
O. M. O. Habib H. M. Hassan E. B. Moawad A. El-Mekabaty 《Petroleum Science and Technology》2013,31(23):2435-2449
Abstract The starting oxazolone 1 was reacted with p-aminophenol in glacial acetic acid to afford imidazolone 2, which afforded Mannich base 3 via the reaction with piperidine and paraformaldehyde. Moreover, the reaction of 2 with ethylchloroacetate or chloroacetic acid in dry acetone gave the corresponding imidazolones 4 and 5, respectively. Compound 4 reacted with benzylamine or 4-chlorobenzaldehyde to furnish 6 and 7, respectively. On the other hand, oxazolone 1 reacted with hydrazines in glacial acetic acid to afford the 1,2,4-triazines 11–15. Representative compounds of the synthesized products were established and evaluated as antioxidant and corrosion inhibitors for gasoline lube oils. 相似文献
32.
Depiction of precipitation change by elevation in an areaindicates the possibilities of orographic rainfall occurrencesin the mountainous regions. In general, precipitation increaseswith elevation but sometimes inverse cases occur locally due toorographic and meteorological features of the area. Inpractice, prior to any quantitative modeling, qualitativeassessments and interpretations help to have sound foundationsin search for a suitable model. In this article, standardizedpoint cumulative semivariogram (SPCSV) methodology is employedfor identification of the precipitation-elevationrelationship. According to relative positions of theprecipitation and elevation SPCSVs four different precipitationcategories are suggested. The application of the methodologyproposed is presented for the precipitation records from YuccaMountain, Nevada, U.S.A. 相似文献
33.
34.
Sitai Liang Bijaya K. Nayak Kristine S. Vogel Samy L. Habib 《International journal of molecular sciences》2021,22(8)
The role of tumor protein 63 (TP63) in regulating insulin receptor substrate 1 (IRS-1) and other downstream signal proteins in diabetes has not been characterized. RNAs extracted from kidneys of diabetic mice (db/db) were sequenced to identify genes that are involved in kidney complications. RNA sequence analysis showed more than 4- to 6-fold increases in TP63 expression in the diabetic mice’s kidneys, compared to wild-type mice at age 10 and 12 months old. In addition, the kidneys from diabetic mice showed significant increases in TP63 mRNA and protein expression compared to WT mice. Mouse proximal tubular cells exposed to high glucose (HG) for 48 h showed significant decreases in IRS-1 expression and increases in TP63, compared to cells grown in normal glucose (NG). When TP63 was downregulated by siRNA, significant increases in IRS-1 and activation of AMP-activated protein kinase (AMPK (p-AMPK-Th172)) occurred under NG and HG conditions. Moreover, activation of AMPK by pretreating the cells with AICAR resulted in significant downregulation of TP63 and increased IRS-1 expression. Ad-cDNA-mediated over-expression of tuberin resulted in significantly decreased TP63 levels and upregulation of IRS-1 expression. Furthermore, TP63 knockdown resulted in increased glucose uptake, whereas IRS-1 knockdown resulted in a decrease in the glucose uptake. Altogether, animal and cell culture data showed a potential role of TP63 as a new candidate gene involved in regulating IRS-1 that may be used as a new therapeutic target to prevent kidney complications in diabetes. 相似文献
35.
K. Habib 《Journal of Failure Analysis and Prevention》2010,10(5):427-433
The temperature versus thermal deformation (strain) with respect to time, of different coating films was studied by a non-destructive technique (NDT) known as shearography. The behavior of organic coatings, i.e., epoxy, a white enamel, or a yellow acrylic lacquer on carbon steels, was investigated at a temperature range simulating the severe weather temperatures in Kuwait especially 20–60 °C differences between the daylight and the night time temperatures. The investigation focused on determining the in-plane displacement of the coatings, which amounts to the thermal deformation that results from the applied temperature range. Furthermore, the investigation also focused on determining the thermal expansion coefficients of coatings and the slope of the plot of the thermal deformation versus the applied temperature range. A critical (steady state) value of the thermal expansion coefficients of coatings was used to determine the integrity of the coatings with respect to time. This value was determined from the decreasing, time-dependent value of the thermal expansion coefficients of coatings. In fact, determination of critical (steady state) value of the thermal expansion coefficients of coatings could be accomplished independent of parameters such as UV exposure, humidity, presence of chemical species, and other parameters normally considered in conventional methods of the assessing of the integrity of coatings. By using the technique of shearography, one needs only to determine the critical (steady state) value of the thermal expansion coefficients of coatings, regardless of the history of the coating, in order to assess the integrity of coatings. These results indicate that the technique is a very useful NDT method for determining the critical value of the thermal expansion coefficients of different coatings and can be used as a 2D-microscope for monitoring the deformation of the coatings in real-time at a submicroscopic scale. 相似文献
36.
Dipl.-Inf. Habib Lejmi Dipl.-Wirtsch.-Inf. Gerald Butterwegge 《WIRTSCHAFTSINFORMATIK》2002,44(6):535-544
The integration of logistic services into electronic marketplaces for goods leads to significant advantages for all parties concerned. This paper illustrates a supplementary component for B2B marketplaces that intends to optimise the delivery processes. This component bundles the orders of neighboured purchasers and achieves considerable savings. Moreover, its use on a marketplace in the furniture industry demonstrates how small and medium sized enterprises (SMEs) can benefit from intensifying their cooperation via an electronic marketplace. 相似文献
37.
The paper derives a spiral condition, for a single Pythagorean hodograph quintic transition curve of G2 contact, between two circles with one circle inside the other. A spiral is free of local curvature extrema, making spiral designs an interesting mathematical problem with importance for both physical and aesthetic applications. In the construction of highways or railway routes in particular, it is often desirable to have a transition curve from circle to circle. Here, we treat an open problem on planar quintic spiral segments, called transition curve elements, examine techniques for curve design using the new results, and derive lower and upper bounds for the distance between the two circles. The proposed method is applicable for non-tangent and non-concentric circles. 相似文献
38.
Zolfaghar Salmanian Habib Izadkhah Ayaz Isazadeh 《The Journal of supercomputing》2017,73(12):5221-5238
Planning a powerful server imposes an enormous cost for providing ideal performance. Given that a server responding for web requests is more likely to consume RAM memory than other resources, it is desirable to provide an appropriate RAM capacity for optimal performance of server in congested situations. This can be done through RAM usage modeling and its performance evaluation. In the literature, modeling of RAM usage is not provided with mathematical modeling. We propose an approach to model RAM usage of such a server, based on birth–death process in this article. The model can be used to figure out an operation research problem of finding minimum RAM capacity covering intended constraints elicited from birth–death queuing system. We show how optimal RAM capacity can be obtained using our approach with an illustrative example. 相似文献
39.
Rachid El-Azouzi Francesco De Pellegrini Habib B.A. Sidi Vijay Kamble 《Computer Networks》2013,57(4):1003-1018
In this paper, we apply evolutionary games to non-cooperative forwarding control in Delay Tolerant Networks (DTNs). The main focus is on mechanisms to rule the participation of the relays to the delivery of messages in DTNs. Thus, we express the success probability as a function of the competition that takes place within a large population of mobiles, and we characterize the effect of reward-based mechanisms on the performance of such systems. Devices acting as active relays, in fact, sacrifice part of their batteries in order to support message replication and thus increase the probability to reach the destination. In our scheme, a relay can choose the strategy by which they participate to the message relaying. A mobile that participates receives a unit of reward based on the reward mechanism selected by the network. A utility function is introduced as the difference between the expected reward and the energy cost, i.e., the cost spent by the relay to sustain forwarding operations. We show how the evolution dynamics and the equilibrium behavior (called Evolutionary Stable Strategy – ESS) are influenced by the characteristics of inter contact time, energy expenditure and pricing characteristics.We extend our analysis to mechanisms that the system can introduce in order to have the message delivered to the destination with high probability within a given deadline and under energy constraints which bound the number of released copies per message. Finally, we apply our findings in order to devise decentralized forwarding algorithms that are rooted in the theory of stochastic approximations. Thus, we demonstrate that the ESS can be attained without complete knowledge of the system state and letting the source monitor number of released copies per message only. We provide extensive numerical results to validate the proposed scheme. 相似文献
40.
A videogrammetric as-built data collection method for digital fabrication of sheet metal roof panels
A roofing contractor typically needs to acquire as-built dimensions of a roof structure several times over the course of its build because a structure is never built to the exact drawing dimensions. In the construction phase and in order to digitally fabricate sheet metal roof panels, the contractor has to measure end-to-end dimensions of boundaries of every roof plane with a certain level of accuracy (i.e., errors less than ±2 cm). This is necessary to be able to cut sheet metal coil such that different pieces perfectly fit together. Obtaining these measurements using the exiting roof surveying methods could be costly in terms of equipment, labor, and/or worker exposure to safety hazards. This paper presents a video-based surveying framework as an alternative method which is simple to use, automated, less expensive, and safe. When using this framework, the contractor collects video streams with a calibrated stereo camera set. The captured data is processed to automatically generate a 3D wire-diagram of the target roof. Measurements from the wire-diagram are saved in a digital file (XML format) which could be loaded into an on-site sheet metal folding and cutting machine. Experimental analyses demonstrate applicability of the proposed framework. 相似文献