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991.
Müller A Weiss SC Beisswenger J Leukhardt HG Schulz W Seitz W Ruck WK Weber WH 《Water research》2012,46(3):679-690
During the treatment of surface water to drinking water, ozonation is often used for disinfection and to remove organic trace substances, whereby oxidation by-products can be formed. Here we use the example of tolyltriazole to describe an approach for identifying relevant oxidation by-products in the laboratory and subsequently detecting them in an industrial-scale process. The identification process involves ozonation experiments with pure substances at laboratory level (concentration range mg L−1). The reaction solutions from different ozone contact times were analyzed by high performance liquid chromatography - quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) in full scan mode. Various approaches were used to detect the oxidation by-products: (i) target searches of postulated oxidation by-products, (ii) comparisons of chromatograms (e.g., UV/VIS) of the different samples, and (iii) color-coded abundance time courses (kinetic) of all detected compounds were illustrated in a kind of a heat map. MS/MS, H/D exchange, and derivatization experiments were used for structure elucidation for the detected by-product. Due to the low contaminant concentrations (ng L−1-range) of contaminants in the untreated water, the conversion of results from laboratory experiments to an industrial-scale required the use of HPLC-MS/MS with sample enrichment (e.g., solid phase extraction.) In cases where reference substances were not available or oxidation by-products without clear structures were detected, reaction solutions from laboratory experiments were used to optimize the analytical method to detect ng L−1 in the samples of the industrial processes. We exemplarily demonstrated the effectiveness of the methodology with the industrial chemicals 4- and 5-methyl-1H-benzotriazole (4- and 5-MBT) as an example. Moreover, not only did we identify several oxidation by-products in the laboratory experiments tentatively, but also detected three of the eleven reaction products in the outlet of the full-scale ozonation unit. 相似文献
992.
993.
994.
Improved absorption characteristics of thermally modified beech veneer produced by plasma treatment 总被引:1,自引:1,他引:0
Georg Avramidis Holger Militz István Avar Wolfgang Vi?l Arndt Wolkenhauer 《Holz als Roh- und Werkstoff》2012,70(5):545-549
In this study the effect of an atmospheric pressure plasma treatment by a dielectric barrier discharge (DBD) on the wettability and absorption characteristics of thermally modified beech veneer is investigated. A common immersion test using water and melamine solution has been conducted and showed improved wettability and liquid uptake after plasma treatment. Determination of the weight percent gain (WPG) confirmed increased melamine content after plasma treatment. 相似文献
995.
Cho J Tauer LW Schukken YH Gómez MI Smith RL Lu Z Grohn YT 《Journal of dairy science》2012,95(4):1855-1872
Johne's disease, or paratuberculosis, is a chronic infectious enteric disease of ruminants, caused by infection with Mycobacterium avium ssp. paratuberculosis (MAP). Given the absence of a fail-safe method of prevention or a cure, Johne's disease can inflict significant economic loss on the US dairy industry, with an estimated annual cost of over $200 million. Currently available MAP control strategies include management measures to improve hygiene, culling MAP serologic- or fecal-positive adult cows, and vaccination. Although the 2 first control strategies have been reported to be effective in reducing the incidence of MAP infection, the changes in herd management needed to conduct these control strategies require significant effort on the part of the dairy producer. On the other hand, vaccination is relatively simple to apply and requires minor changes in herd management. Despite these advantages, only 5% of US dairy operations use vaccination to control MAP. This low level of adoption of this technology is due to limited information on its cost-effectiveness and efficacy and some important inherent drawbacks associated with current MAP vaccines. This study investigates the epidemiological effect and economic values of MAP vaccines in various stages of development. We create scenarios for the potential epidemiological effects of MAP vaccines, and then estimate economically justifiable monetary values at which vaccines become economically beneficial to dairy producers such that a net present value (NPV) of a farm's net cash flow can be higher than the NPV of a farm using no control or alternative nonvaccine controls. Any vaccination with either low or high efficacy considered in this study yielded a higher NPV compared with a no MAP control. Moreover, high-efficacy vaccines generated an even higher NPV compared with alternative controls, making vaccination economically attractive. Two high-efficacy vaccines were particularly effective in MAP control and NPV maximization. One was a high-efficacy vaccine that reduced susceptibility to MAP infection. The other was a high-efficacy vaccine that had multiple efficacies on the dynamics of MAP infection and disease progress. Only one high-efficacy vaccine, in which the vaccine is targeted at reducing MAP shedding and the number of clinical cases, was not economically beneficial to dairy producers compared with an alternative nonvaccine control, when herds were highly infected with MAP. 相似文献
996.
摘译立体匹配是一种从两幅或多幅2D图像中计算捕获对象或场景等深度信息的技术。其可广泛应用于多种领域,如遥感、机器人学、考古学、文化遗产、逆向工程和三维人脸识别等。它是唯一可产生深度信息的被动方法,意味着不会与目标物之间产生相互作用,只使用自然光进行数据采集。 相似文献
997.
Georg R. Meseck Roman Kontic Greta R. Patzke Stefan Seeger 《Advanced functional materials》2012,22(21):4433-4438
Nanoscale TiO2 photocatalysts are key materials for convenient wastewater treatment and other essential cleaning processes. Immobilization of TiO2 nanoparticles (NPs) is thus indispensable for the facile handling and separation of nanocatalysts as well as for minimizing their potential health and environmental hazards. Silicone nanofilaments are introduced as a new flexible carrier type for titania NPs because they are compatible with a wide range of substrates and they display high chemical stability. TiO2‐NPs are deposited on glass slides covered with thin carpets of silicone nanofilaments in a single reaction step starting from TiF4 and optimized ethanol/water ratios. The resulting composites are characterized using a wide range of electron microscopy and other analytical techniques, and their photocatalytic activity in the decomposition of methylene blue (MB) is superior to immobilized TiO2 references on plain substrates. 相似文献
998.
Nikolaos Peltekis Shishir Kumar Niall McEvoy Kangho Lee Anne Weidlich Georg S. Duesberg 《Carbon》2012,50(2):395-403
This paper reports on the effects of growth, transfer and annealing procedures on graphene grown by chemical vapour deposition. A combination of Raman spectroscopy, electrical measurements, atomic force microscopy, and X-ray photoemission spectroscopy allowed for the study of inherent characteristics and electronic structure of graphene films. Contributions from contaminants and surface inhomogeneities such as ripples were also examined. A new cleaning and reconstruction process for graphene, based on plasma treatments and annealing is presented, opening a new pathway for control over the surface chemistry of graphene films. The method has been successfully used on contacted graphene samples, demonstrating its potential for in situ cleaning, passivation and interface engineering of graphene devices. 相似文献
999.
Arsenic‐containing hydrocarbons and arsenic‐containing fatty acids: Transfer across and presystemic metabolism in the Caco‐2 intestinal barrier model 下载免费PDF全文
1000.
High‐throughput continuous flow femtosecond laser‐assisted cell optoporation and transfection 下载免费PDF全文
Hans Georg Breunig Aisada Uchugonova Ana Batista Karsten König 《Microscopy research and technique》2014,77(12):974-979
We present a femtosecond‐laser based nanoprocessing system for transient optical cell membrane poration to allow the introduction of foreign molecules into the interior of a cell with very high throughput. In the setup, cells flow through a micro‐flow tube for spatial confinement and are simultaneously targeted by fs laser radiation. Beam‐shaping generates a focal geometry along a line which is scanned across the micro‐flow cell to increase the number of reachable cells. Successful cell membrane poration was observed indirectly by cell transfection even with cell‐light interaction times in the millisecond range. The system was characterized by experiments with Chinese hamster ovary cells regarding cell viability, the uptake of extrinsic molecules and cell transfection efficiency. The continuous flow of cells enables a tremendous increase of cell throughput compared to previous nonflow approaches by treating millions of cells, although with only limited efficiency. The setup opens the possibility to realize a completely automated high‐throughput laser‐assisted cell‐poration system which could be integrated in lab‐on‐a‐chip devices. Microsc. Res. Tech. 77:974–979, 2014. © 2014 Wiley Periodicals, Inc. 相似文献