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排序方式: 共有2707条查询结果,搜索用时 31 毫秒
1.
Hubby Izzuddin Shigenari Hayashi Suzue Yoneda Takashi Kogin Eiji Ishikawa Manabu Noguchi 《工业材料与腐蚀》2020,71(9):1488-1499
The effect of Mo on the corrosion behavior of Ni20Cr–xMo alloys in an oxidizing chlorine-containing atmosphere using air mixed with the salt-vapor mixture of NaCl–KCl–CaCl2 at 570°C was investigated. The results revealed that the corrosion performance of the Ni20Cr alloys in the oxidizing chlorine atmosphere was improved by Mo addition of up to 3 wt%. The Mo-free alloy formed a potassium chromate during corrosion as a result of the reaction between the Cr2O3 scale and KCl vapor. The chromate formation increased the chlorine potential at the scale surface and induced the breakdown of the protective Cr2O3 scale, resulting in internal chromium chloride precipitates and a Cr-depleted zone. In contrast, the presence of Mo resulted in the formation of a NiO scale, which did not react with the salt vapors and, therefore, prevented the formation of chromates. The beneficial effect of Mo on the high-temperature chlorination of Ni–Cr alloys in salt-vapor-containing atmospheres was ascribed to the suppression of chlorine generation due to NiO scale formation. 相似文献
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《International Journal of Hydrogen Energy》2020,45(49):26080-26089
In this paper, an atmospheric-pressure distillation system is designed and constructed for partial to separation of hydrochloric acid and water. The system concentrates HCl(aq) between the electrolyzer and hydrolysis processes of the Copper–Chlorine (Cu–Cl) cycle for hydrogen production. The motivation behind this study is to investigate azeotropic separation of HCl(aq), as needed for integration of unit operations in the Cu–Cl cycle. The separation is only partial, as the mixture is unable to cross the azeotrope with only a single pressure. The distillation system consists primarily of one packed distillation column, which employs heating tapes and thermocouples to achieve a desired axial temperature profile. The column can be operated in batch or continuous mode. The distillate is H 2O(l) and the bottoms is HCl(aq) near the azeotropic concentration; feed concentrations are less than azeotrope. Thus, the degree of separation is determined to be independent of the feed concentration. The bottoms concentration varies from experiment to experiment, but does so independently of feed concentration, likely the result of corrosion impurities affecting the calculation of its concentration. It is found that HCl(aq) can be concentrated up to approximately 0.1068 mol/mol from an initial concentration of 0.0191 mol/mol. A simulation of pressure-swing distillation (PSD) is also performed, but due to safety constraints (a column operating at 10 atm must be certified to CSA B51), a single-pressure (single-column) distillation is physically performed. A single-pressure column is beneficial to the Cu–Cl cycle because it partially recycles HCl, which reduces the cost of the cycle, and still provides valuable results for analysis. The maximum HCl concentration achieved experimentally is 0.1068 mol/mol and the maximum HCl concentration determined from simulation is 0.11 mol/mol (the azeotropic concentration). The novelty of this research is that the experimental column built to study HCl partial separation is designed to be simple yet safe to integrate within the Cu–Cl cycle for hydrogen production. 相似文献
4.
针对旁路烟道旋转喷雾干燥技术和主烟道蒸发技术,开展了脱硫废水蒸发干燥过程及其产物特性的分析对比研究,比较了两种工艺过程中脱硫废水蒸发特性,并对脱硫废水蒸发产物的表面结构特性进行了研究,考察了Cl元素的迁移分布特性及其对后续除尘系统和粉煤灰资源化利用的影响。结果表明:氯离子浓度增大,蒸发效果会随之降低,pH值则对其影响不大,旋转雾化条件较之于主烟道蒸发效果好;两种工艺下蒸发干燥产物表面粗糙,烟道出口S元素含量增加明显,Ca、Mg、K等元素略有增加,蒸发后产物大致相同,由于温度的不同,旋转雾化条件主要是以莫来石、SiO_2、Al_2O_3、 KCl、MgSO_4、CaSO_4·0.5H_2O为主,主烟道蒸发则是以莫来石、SiO_2、Al_2O_3、KCl、MgSO_4·H_2O、CaSO_4·0.5H_2O和CaSO_4·2H_2O等为主;废水中氯离子浓度对氯元素以HCl形式进入烟气影响不大,而碱性脱硫废水则可以有效抑制其以HCl形式析出。 相似文献
5.
Zachary Finewax Demetrios Pagonis Megan S. Claflin Anne V. Handschy Wyatt L. Brown Olivia Jenks Benjamin A. Nault Douglas A. Day Brian M. Lerner Jose L. Jimenez Paul J. Ziemann Joost A. de Gouw 《Indoor air》2021,31(5):1323-1339
Humans spend approximately 90% of their time indoors, impacting their own air quality through occupancy and activities. Human VOC emissions indoors from exercise are still relatively uncertain, and questions remain about emissions from chlorine-based cleaners. To investigate these and other issues, the ATHLETic center study of Indoor Chemistry (ATHLETIC) campaign was conducted in the weight room of the Dal Ward Athletic Center at the University of Colorado Boulder. Using a Vocus Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOF), an Aerodyne Gas Chromatograph (GC), an Iodide-Chemical Ionization Time-of-Flight Mass Spectrometer (I-CIMS), and Picarro cavity ringdown spectrometers, we alternated measurements between the weight room and supply air, allowing for determination of VOC, NH3, H2O, and CO2 emission rates per person (emission factors). Human-derived emission factors were higher than previous studies of measuring indoor air quality in rooms with individuals at rest and correlated with increased CO2 emission factors. Emission factors from personal care products (PCPs) were consistent with previous studies and typically decreased throughout the day. In addition, N-chloraldimines were observed in the gas phase after the exercise equipment was cleaned with a dichlor solution. The chloraldimines likely originated from reactions of free amino acids with HOCl on gym surfaces. 相似文献
6.
Linhui Lu Qingli Shu Guiru Zhang Qi Zhang Ping Du Xuedong Zhu 《American Institute of Chemical Engineers》2022,68(10):e17787
Palladium-based catalysts have been widely employed in the electro-Fenton process for in situ generation of H2O2. However, the process is still far from being practical on a large scale. In this work, a series of ClxFePd/γ-Al2O3/Al catalysts were prepared by a three-step-impregnation method. They exhibited excellent activity in H2O2 in situ synthesis and high efficiency in phenol degradation. The characterization results showed that Cl could assist in increasing the content of Pd0 and reducing the isoelectric point of catalysts, which led to the drastic promotion in the synthesis of H2O2. Theoretical calculations further demonstrated that Cl doping could facilitate the main reaction in H2O2 synthesis, as well as inhibit side reactions such as dissociation of the O O bond. Furthermore, kinetic models were proposed and fitted. A plausible reaction mechanism as well as degradation pathways were elaborated based on electron spin resonance and gas chromatography–mass spectrometry results. These findings illustrate the value of palladium-based ClxFePd/γ-Al2O3/Al catalysts for their application in the electro-Fenton process. 相似文献
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9.
Effect of oxidants on microalgal flocculation 总被引:5,自引:0,他引:5
The effects of chlorine, ozone and chlorine dioxide on Scenedesmus sp. cultures were studied. Algal cell viability and chlorophyll concentration decreased, and the concentration of dissolved organic substances increased with increasing applied oxidant concentration. Pretreatment with chlorine dioxide (1, 3 or 5 mg l−1) or ozone (2.6, 4.6 or 8.1 mg l−1) on algal cultures enhanced algal flocculation with alum, while prechlorination with 10 or 20 mg l−1 increased the required dosage of alum by 15%. Scanning electron micrographs of oxidized cells revealed drastically adverse effects upon the cell surface architecture: in addition to the oxidation of noncellular organic materials, the oxidants damaged both cell surface structures and intracellular components. A model explaining the effects of the different oxidants on microalgal flocculation is suggested. 相似文献
10.
多年冻土和人工冻土的爆破试验与方法研究 总被引:1,自引:0,他引:1
阐述了冻土爆破方法研究的必要性 ,介绍了冻土爆破漏斗、掏槽爆破及光面爆破试验的研究成果 ,根据近几年的理论研究和现场实验研究 ,总结了我国多年冻土和季节冻土的爆破方法及矿山冻结法施工的冻土爆破方法。 相似文献