全文获取类型
收费全文 | 4945篇 |
免费 | 243篇 |
国内免费 | 457篇 |
专业分类
电工技术 | 226篇 |
综合类 | 303篇 |
化学工业 | 691篇 |
金属工艺 | 332篇 |
机械仪表 | 267篇 |
建筑科学 | 292篇 |
矿业工程 | 159篇 |
能源动力 | 71篇 |
轻工业 | 330篇 |
水利工程 | 131篇 |
石油天然气 | 236篇 |
武器工业 | 28篇 |
无线电 | 534篇 |
一般工业技术 | 1362篇 |
冶金工业 | 145篇 |
原子能技术 | 97篇 |
自动化技术 | 441篇 |
出版年
2024年 | 68篇 |
2023年 | 195篇 |
2022年 | 264篇 |
2021年 | 313篇 |
2020年 | 165篇 |
2019年 | 196篇 |
2018年 | 168篇 |
2017年 | 93篇 |
2016年 | 109篇 |
2015年 | 146篇 |
2014年 | 183篇 |
2013年 | 184篇 |
2012年 | 481篇 |
2011年 | 598篇 |
2010年 | 216篇 |
2009年 | 194篇 |
2008年 | 407篇 |
2007年 | 304篇 |
2006年 | 295篇 |
2005年 | 215篇 |
2004年 | 137篇 |
2003年 | 77篇 |
2002年 | 99篇 |
2001年 | 91篇 |
2000年 | 66篇 |
1999年 | 72篇 |
1998年 | 56篇 |
1997年 | 60篇 |
1996年 | 54篇 |
1995年 | 38篇 |
1994年 | 26篇 |
1993年 | 9篇 |
1992年 | 18篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 13篇 |
1981年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有5645条查询结果,搜索用时 31 毫秒
71.
Adsorption process is considered to be the most promising alternative for the CO2 capture to the traditional energy-intensive amine absorption process, and the development of feasible and efficient CO2 adsorbents is still a challenge. In this work, the NiO@USY (ultrastable Y) composites with different NiO loadings were prepared for the CO2 adsorption using Ni(NO3)2 as the precursor. The composites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen adsorption–desorption test, scanning electron microscopy analysis, and thermogravimetric analysis, and were evaluated for the CO2 adsorption capacity, CO2/N2 adsorption selectivity and CO2 cycle adsorption capacity. The characterization results show that after the activation at 423 K, the Ni(NO3)2 species were well dispersed into the surface of zeolite USY, and after the further activation at 823 K, Ni(NO3)2 could be converted into highly dispersed NiO. The adsorption results show that the presence of the active component NiO plays an important role in improving the CO2 adsorption performance, and the NiO@USY composite with a NiO loading of 1.5 mmol·g-1 USY support displays a high adsorption capacity and adsorption selectivity for CO2, and shows a good cycle stability. In addition, the Clausius–Clapeyron equation was used to evaluate the isosteric heat of adsorption of CO2 on the NiO(1.5)@USY composite, and the heat of adsorption was 17.39–38.34 kJ·mol-1. 相似文献
72.
Pascal Habimana Yanjun Jiang Jing Gao Jean Bernard Ndayambaje Osama M. Darwesh Jean Pierre Mwizerwa Xiaobing Zheng Li Ma 《中国化学工程学报》2022,48(8):66-75
The continuous use of chemical dyes in various industries, and their discharge into industrial effluents, results in severe problems to human life and water pollution. Laccases have the ability to decolorize dyes and toxic chemicals in industrial effluents as green biocatalysts. Their possible industrial applications have been limited by poor reusability, low stability, and loss of free laccase action. In this research, laccase was immobilized on zeolitic imidazolate framework coated multi-walled carbon nanotubes (Laccase@ZIF-8@MWCNTs) via metal affinity adsorption to develop an easy separable and stable enzyme. The optimum reaction conditions for immobilized laccase are at a pH of 3.0 and a temperature of 60?℃. The immobilized laccase was enhanced in storage and thermal stability. The results indicated that Laccase@ZIF-8@MWCNTs still maintained 68% of its original activity after 10 times of repeated use. Most importantly, the biocatalytic system was applied for decolorization of different dyes (20?mg·L?1) without a mediator, and up to 97.4% for Eriochrome black T and 95.6% Acid red 88 was achieved in 25 min. Biocatalysts with these properties may be used in a variety of environmental and industrial applications. 相似文献
73.
Fengfeng Gao Jinhua Luo Xuefeng Zhang Xiaogang Hao Guoqing Guan Zhong Liu Jun Li Qinglong Luo 《中国化学工程学报》2022,49(9):161-169
Effective extraction and regeneration of radioactive iodide is one of urgent concerns for the safe utilization of nuclear energy. As a novel environmentally benign ion separation technique, electrochemically switched ion extraction (ESIE) process can be applied for effective capture and recovery of iodide ions (I-). Herein, a novel kelp seaweed-like core/shell I- imprinted polypyrrole@bismuth oxyiodide (PPy/I-@BiOI) composite film is successfully prepared for the selective I- capture in the ESIE system. It is found that the I- can be easily trapped in the PPy/I-@BiOI film after I- is in situ desorbed from the film by an electrochemical reduction process since it offers particular electroactive binding sites for I- extraction. The I- imprinted PPy/I-@BiOI film displays an extraction capacity as high as 325.2 mg·g-1 for I- with favorable stability. In particular, the extraction and desorption of I- is achieved by adjusting the redox potential and the pristine PPy/I-@BiOI film can be regenerated and reused for multiple times without decrease in extraction capacity. It is expected that such a PPy/I-@BiOI film would be useful as an electrochemically switched renewable extractor that could capture and regenerate I- from radioactive water. 相似文献
74.
In the face of human society's great requirements for health industry, and the much stricter safety and quality standards in the biomedical industry, the demand for advanced membrane separation technologies continues to rapidly grow in the world. Nanofiltration (NF) and reverse osmosis (RO) as the high-efficient, low energy consumption, and environmental friendly membrane separation techniques, show great promise in the application of biomedical separation field. The chemical compositions, microstructures and surface properties of NF/RO membranes determine the separation accuracy, efficiency and operation cost in their applications. Accordingly, recent studies have focused on tuning the structures and tailoring the performance of NF/RO membranes via the design and synthesis of various advanced membrane materials, and exploring universal and convenient membrane preparation strategies, with the objective of promoting the better and faster development of NF/RO membrane separation technology in the biomedical separation field. This paper reviews the recent studies on the NF/RO membranes constructed with various materials, including the polymeric materials, different dimensional inorganic/organic nanomaterials, porous polymeric materials and metal coordination polymers, etc. Moreover, the influence of membrane chemical compositions, interior microstructures, and surface characteristics on the separation performance of NF/RO membranes, are comprehensively discussed. Subsequently, the applications of NF/RO membranes in biomedical separation field are systematically reported. Finally, the perspective for future challenges of NF/RO membrane separation techniques in this field is discussed. 相似文献
75.
76.
To increase antibody secretion and dose sparing, squalene-in-water aluminium hydrogel (alum)-stabilised emulsions (ASEs) have been developed, which offer increased surface areas and cellular interactions for higher antigen loading and enhanced immune responses. Nevertheless, the squalene (oil) in previous attempts suffered from limited oxidation resistance, thus, safety and stability were compromised. From a clinical translational perspective, it is imperative to screen the optimal oils for enhanced emulsion adjuvants. Here, because of the varying oleic to linoleic acid ratio, soybean oil, peanut oil, and olive oil were utilised as oil phases in the preparation of aluminium hydrogel-stabilised squalene-in-water emulsions, which were then screened for their stability and immunogenicity. Additionally, the underlying mechanisms of oil phases and emulsion stability were unravelled, which showed that a higher oleic to linoleic acid ratio increased anti-oxidative capabilities but reduced the long-term storage stability owing to the relatively low zeta potential of the prepared droplets. As a result, compared with squalene-in-water ASEs, soybean-in-water ASEs exhibited comparable immune responses and enhanced stability. By optimising the oil phase of the emulsion adjuvants, this work may offer an alternative strategy for safe, stable, and effective emulsion adjuvants. 相似文献
77.
Siliu Lyu Muhammad Adnan Younis Zhibin Liu Libin Zeng Xianyun Peng Bin Yang Zhongjian Li Lecheng Lei Yang Hou 《Frontiers of Chemical Science and Engineering》2022,16(6):777
As an eco-friendly, efficient, and low-cost technique, photoelectrochemical water splitting has attracted growing interest in the production of clean and sustainable hydrogen by the conversion of abundant solar energy. In the photoelectrochemical system, the photoelectrode plays a vital role in absorbing the energy of sunlight to trigger the water splitting process and the overall efficiency depends largely on the integration and design of photoelectrochemical devices. In recent years, the optimization of photoelectrodes and photoelectrochemical devices to achieve highly efficient hydrogen production has been extensively investigated. In this paper, a concise review of recent advances in the modification of nanostructured photoelectrodes and the design of photoelectrochemical devices is presented. Meanwhile, the general principles of structural and morphological factors in altering the photoelectrochemical performance of photoelectrodes are discussed. Furthermore, the performance indicators and first principles to describe the behaviors of charge carriers are analyzed, which will be of profound guiding significance to increasing the overall efficiency of the photoelectrochemical water splitting system. Finally, current challenges and prospects for an in-depth understanding of reaction mechanisms using advanced characterization technologies and potential strategies for developing novel photoelectrodes and advanced photoelectrochemical water splitting devices are demonstrated. 相似文献
78.
Dongyang Liu Yibo Zhi Yuen Bai Liang Zhao Jinsen Gao Chunming Xu 《Frontiers of Chemical Science and Engineering》2022,16(12):1700
The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha. Herein, for a better catalyst design and operation parameters optimization, the reaction pathways and equilibrium yields for the catalytic pyrolysis of C5–8 n/iso/cyclo-paraffins were analyzed thermodynamically. The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways, respectively. However, the formation of light paraffin severely limits the maximum selectivity toward light olefins. The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins. The results are thus useful as a direction for future catalyst improvements, facilitating superior reaction pathways to enhance light olefins. In addition, the equilibrium yield of light olefins increased with increasing the chain length, and the introduction of cyclo-paraffin inhibits the formation of light olefins. High temperatures and low pressures favor the formation of ethylene, and moderate temperatures and low pressures favor the formation of propylene. n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90% and 55.77%, respectively. This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C5–8 n/iso/cyclo-paraffins from a thermodynamic point of view. 相似文献
79.
Sonolytic degradation of dimethoate: kinetics, mechanisms and toxic intermediates controlling 总被引:1,自引:0,他引:1
The sonolytic degradation of aqueous solutions of dimethoate, O,O-dimethyl S-[2-(methylamino)-2-oxoethyl]dithiophosphate, was examined. Optimal degradation rates were obtained at 619 kHz for continuous sonolysis and 406 kHz for pulse sonolysis. The primary pathways for degradation include hydroxyl radical oxidation, hydrolysis and pyrolysis on collapsing cavitation bubble interfaces. Reaction mechanisms coupled with the corresponding kinetic models are proposed to reproduce the observed concentration versus time profiles for dimethoate, omethoate and N-(methyl) mercaptoacetamide during sonolysis. The oxidation and hydrolysis of dimethoate and omethoate occurred at the water-bubble interface was the rate-determining step for sonolytic overall degradation of dimethoate. More than 90% toxicity of dimethoate was reduced within 45 min ultrasonic irradiation. Ferrous ion at micro molar level can significantly enhance the sonolytic degradation of dimethoate and effectively reduce the yields of toxic intermediate omethoate. 相似文献
80.
Distributions of polycyclic aromatic hydrocarbons in surface waters, sediments and soils of Hangzhou City, China 总被引:35,自引:0,他引:35
Ten polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in 17 surface water samples and 11 sediments of four water bodies, and 3 soils near the water-body bank in Hangzhou, China in December 2002. It was observed that the sum of PAHs concentrations ranged from 0.989 to 9.663 microg/L in surface waters, from 132.7 to 7343 ng/g dry weight in sediments, and from 59.71 to 615.8 ng/g dry weight in soils. The composition pattern of PAHs by ring size in water, sediment and soil were surveyed. Three-ring PAHs were dominated in surface waters and soils, meanwhile sediments were mostly dominated by four-ring PAHs. Furthermore, PAHs apparent distribution coefficients (K(d)) and solid f(oc)-normalized K(d) (e.g. K(oc)= K(d) / f(oc)) were calculated. The relationship between logK(oc) and logK(ow) of PAHs for field data on sediments and predicted values were compared. The sources of PAHs in different water bodies were evaluated by comparison of K (oc) values in sediments of the river downstream with that in soils. Hangzhou section of the Great Canal was heavily polluted by PAHs released from industrial wastewater in the past and now PAHs in sediment may serve as sources of PAHs in surface water. PAHs in Qiantang River were contributed from soil runoff. Municipal road runoff was mostly contributed to West Lake PAHs. 相似文献