全文获取类型
收费全文 | 208篇 |
免费 | 5篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 3篇 |
综合类 | 3篇 |
化学工业 | 62篇 |
金属工艺 | 9篇 |
机械仪表 | 1篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 34篇 |
轻工业 | 14篇 |
水利工程 | 1篇 |
石油天然气 | 10篇 |
无线电 | 10篇 |
一般工业技术 | 18篇 |
原子能技术 | 1篇 |
自动化技术 | 41篇 |
出版年
2023年 | 11篇 |
2022年 | 5篇 |
2021年 | 24篇 |
2020年 | 30篇 |
2019年 | 24篇 |
2018年 | 3篇 |
2017年 | 14篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 10篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 4篇 |
排序方式: 共有218条查询结果,搜索用时 31 毫秒
1.
Everything you need to know about e-commerce. The term "e-commerce" refers to any commercial transaction type that requires the transmission of information over the Internet. By definition, it uses the Internet as a platform for communication and financial transactions or, at the same time, covering various business activities. In the previous method based on Deep learning and .net for Collaborative Innovation of E-Commerce platform. In the existing method, perception of security and reliability and data integrity and protection are drawbacks of the previous method. The proposed FPGA (Field-programmable gate array) and Convolutional Neural Network (CNN) are used to develop the Collaborative Innovation of E-Commerce platform and easily interface with the network without any complexity. E-commerce is an Internet-based tool, usually the exchange of Internet-based products and services. E-commerce refers to commercial transactions and commercial transactions involving exchange (e.g., money) within organizational or personal boundaries. The Web exchanges cross-organizational or personal boundary value (such as gold) for products and services for commercial transactions and commercial transactions. Here focus effectively on trade between digital companies and individuals. 相似文献
2.
Built-in applications built on a stand-alone device, TCP / IP network and interconnected are a need for high integration with other systems. The system provided through Web services interconnects service-oriented distributed architecture. The TCP / IP network is widely employed to integrate business applications. This integration is still not provided through the embedded application. The applications connected to the Internet are an especially difficult problem in embedded systems to interpret the sensor data. Real-time sensor function generates a training/classification result for IoT application selected, customized, or data structure design. It has an integrated hardware/software system to achieve the continuous training and real-time data analysis and re-training of Machine Learning (ML) algorithm. World of English native speakers on top of all, this is the database of words that have been separated from the local and non-collection English. It also reported a variety of methods that are used in the English vocabulary recognition system. Please check the study of learners of mediation based on the part of the corpus. Students, in writing, too much-advanced technology and general vocabulary. These students, publicly their discourse in and contributed to the professional corpus of "existence" I mentioned that there is a professional writer, is better. To stimulate the different means of integration, it evaluated several network technology today, discussing the balance between the use of shared with this integration in the adaptability and built-in the field of Web network technology of today. 相似文献
3.
Tungsten heavy alloys (WHA) have been widely adopted in many engineering applications due to their excellent physicochemical properties. Microstructure characterization is a very powerful method ranging from testing materials properties to detecting material failures and defects. However, the microstructure of WHA was not well characterized with the sample prepared by conventional method of etching with strong acids, bases or oxidant after polishing for the coarse surface. To solve the problem, the exact characterization of W-Ni-Fe heavy alloys microstructure was conducted using the sample prepared by optimized polishing method. A series of experiments were conducted to find the suitable polishing conditions including polishing pad, abrasive slurry and slurry pH. The results show that a smooth and clear microstructure sample was obtained by polishing with alkaline colloidal silica and IC polishing pad, which contained few defects compared with that obtained by conventional method of etching after polishing. The microstructure of W-Ni-Fe heavy alloys was analyzed by XRD, EDS tests and EPMA detection. The slipping phenomenon was observed in nanoindentation test using the prepared sample for the first time and the mechanism of satisfactory microstructure sample preparation was illustrated. 相似文献
4.
5.
《International Journal of Hydrogen Energy》2019,44(7):3824-3833
The displacement chromatography technique with a tri-column system was used to reduce the protium (H) in the deuterium-tritium (D-T) mixture, and the separation performance was studied numerically by ANSYS FLUENT. The experimental results showed that the isotopic abundance of H in the D-T mixture dropped from 2.7% to an acceptable level of 0.88%. The simulation results showed that a lower porosity (θ) of the filling material made a higher separation factor, but a lower separation efficiency. The velocity of the product gas at the outlet of the separation column approximately had a linear relationship with θ5/3/(1-θ)2, which partly indicated the pore diffusion resistance. The mixed gas could contact the filling materials more sufficiently under a lower flow rate resulting in a lower protium concentration in the product gas. The separation column with a thin and long shape had a better separation performance and a lower product gas loss. 相似文献
6.
7.
Ke Zhang S. A. Kurumov Xiaofang Su Yu. M. Snatenkova Z. M. Bukina N. V. Kolesnichenko Wei Wu S. N. Khadzhiev 《Petroleum Chemistry》2017,57(12):1036-1042
The effect of the method of introduction of zinc cations and the zinc content in a nanocrystalline zeolite of the ZSM-5 type on the physicochemical and catalytic properties of the material in DME conversion to a mixture of liquid synthetic hydrocarbons has been studied. Zinc is introduced into the catalysts both during the zeolite synthesis and the ion exchange (Zn n Al m NZ5 and ZnNZ5, respectively). The use of nanocrystalline Zn n Al m NZ5 zeolites provides the formation of a mixture of liquid hydrocarbons with a high selectivity of no less than 90%; the liquid hydrocarbons contain more than 70% of isoparaffins and a small amount of aromatic compounds. An increase in the zinc loading of the Zn n Al m NZ5 zeolite from 0.9 to ~3% leads to an increase in the methanol content in the aqueous phase of the liquid product, an increase in the selectivity for liquid hydrocarbons, and a slight increase in the concentration of aromatic and unsaturated hydrocarbons in the mixture. In the presence of the ZnNZ5/Al2O3 catalyst with Zn introduced by ion exchange, the methanol content in the aqueous phase and the aromatics content in the liquid hydrocarbon mixture are significantly higher. The Zn n Al m NZ5 nanozeolites are characterized by a more developed external surface, a higher concentration of mesopores, and higher acidity. 相似文献
8.
《Journal of the European Ceramic Society》2022,42(13):5691-5697
Herein, the improvement of the microwave dielectric properties and sintering characteristics of Zn1?xBixVxW1?xO4(x = 0–0.15)-based ceramics is reported. The results showed that an appropriate amount of doping could not only reduce the optimum sintering temperature from 1100° to 900°C, but also enhance the densification of the microstructures and increase the Q×f value from 5351 to 42525 GHz. Additionally, various structural parameters including the phase composition, crystal structure, vibrational and chemical bond characteristics that are correlated with the dielectric properties were systematically investigated. By considering the chemical bond characteristics, the first-principles calculations and the acquired Raman spectra, the interaction between W-O is stronger than Zn-O in the ZnWO4 structure, while the interaction between V-O is stronger than Bi-O in BiVO4. Interestingly, when the Zn0.97Bi0.03V0.03W0.97O4-based ceramics were sintered at 900 °C, improved microwave dielectric properties were acquired (εr =18.32, Q×f=42525 GHz, τf=?67.51 ppm/°C), which provides a promising candidate in low-temperature co-fired ceramics technology. 相似文献
9.
A thermally activated delayed fluorescent (TADF) emitter, 2,7-bis(9,9-dimethylacridin-10(9H)-yl)-9,9-dimethyl-9H-thioxanthene 10,10-dioxide (DMTDAc), was developed as a deep blue TADF emitter using a rigid 9,9-dimethyl-9H-thioxanthene 10,10-dioxide (DMTD) acceptor and an acridine donor. The rigid DMTD acceptor narrowed emission spectrum of DMTDAc by interlocking two phenyl units of diphenylsulfone. A deep blue TADF device with an external quantum efficiency close to 20% with a deep blue color coordinate of (0.15,0.13) was provided using the DMTDAc TADF emitter. 相似文献
10.
Basalt fiber (BF) filled high density polyethylene (HDPE) and co-extruded wood plastic composites (WPCs) with BF/HDPE composite shell were successfully prepared and their mechanical, morphological and thermal properties characterized. The BFs had an average diameter of 7 μm with an organic surfactant surface coating, which was thermally decomposed at about 210 °C. Incorporating BFs into HDPE matrix substantially enhanced flexural, tensile and dynamic modulus without causing a noticeable decrease in the tensile and impact strength of the composites. Micromechanical modeling of tensile properties for the BF/HDPE composites showed a good fit of the selected models to the experimental data. Compared to neat HDPE, BF/HDPE composites had reduced linear coefficient of thermal expansion (LCTE) values. The use of the pure HDPE and BF/HDPE layers over a WPC core greatly improved impact strength of core–shell structured composites. However, the relatively less-stiff HDPE shell with large LCTE values decreased the overall composite modulus and thermal stability. Both flexural and thermal expansion properties were enhanced with BF reinforced HDPE shells, leading to well-balanced properties of core–shell structured material. Cone calorimetry analysis indicated that flammability performance of core–shell structured composites was improved as the BF content increased in the shell layer. 相似文献