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41.
介绍了CENTUM CS3000集散控制系统在PVC聚合中途注低温水工艺中的应用情况,分析了聚合过程控制方案,给出了详细的聚合釜温度及冷凝器控制组态。该控制系统可使聚合釜温度偏差控制在±0.1℃以内,保证了聚合生产的稳定进行。 相似文献
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《Carbon》2014
Titanium dioxide nanoparticles prepared in situ by sol–gel method were supported on a spherical activated carbon to prepare TiO2/AC hybrid photocatalysts for the oxidation of gaseous organic compounds. Additionally, a granular activated carbon was studied for comparison purposes. In both types of TiO2/AC composites the effect of different variables (i.e., the thermal treatment conditions used during the preparation of these materials) and the UV-light wavelength used during photocatalytic oxidation were analyzed. The prepared materials were deeply characterized (by gas adsorption, TGA, XRD, SEM and photocatalytic propene oxidation). The obtained results show that the carbon support has an important effect on the properties of the deposited TiO2 and, therefore, on the photocatalytic activity of the resulting TiO2/AC composites. Thus, the hybrid materials prepared over the spherical activated carbon show better results than those prepared over the granular one; a good TiO2 coverage with a high crystallinity of the deposited titanium dioxide, which just needs an air oxidation treatment at low-moderate temperature (350–375 °C) to present high photoactivity, without the need of additional inert atmosphere treatments. Additionally, these materials are more active at 365 nm than at 257.7 nm UV radiation, opening the possibility of using solar light for this application. 相似文献
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《International Journal of Hydrogen Energy》2020,45(7):5055-5066
In this paper, a novel Ag NPs-PANI/MnO2 tag was synthesized for the first time, and the electrochemical immunoassay for carcinoembryonic antigen (CEA) was achieved. In this experiment, gold nanoparticles (Au NPs) were used as an electrochemical sensing platform to increase conductivity and improve electrode surface capture antibody (Ab1). We use PANI as a green sacrificial agent reduces Ag NPs and MnO2, while improving the conductivity and electrochemical stability of the immunosensor. MnO2 and Ag NPs effectively raise the sensitivity of the sensor by catalytically reducing hydrogen peroxide (H2O2) into water and oxygen to achieve a double amplified sensing signal. It is found that the surface plasmon resonance of Ag NPs has an interesting SERS characteristic structure, and the equivalent circuit simulation of the electrode assembly process results in an error of less than 10%, indicating that the electrochemical immunosensor is successfully prepared. Under optimal conditions, the electrochemical immunosensor has a linear range of 0.0005–80 ng/mL and a detection limit of 0.17 pg/mL (S/N = 3). The immunosensor is expected to be used in clinical laboratories to detect CEA and other tumor markers in human plasma for precancerous screening or surveillance. 相似文献
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Bing Chen Keru Wang Guoqing Zhou Junhua Bai 《International journal of remote sensing》2013,34(9):2706-2724
High spatial or spectral resolution remote sensing might be an efficient method for estimating Verticillium wilt incidence in cotton. The objectives of this study were to characterize leaf spectra and the physiological and biochemical parameters of cotton (Gossypium hirsutum) damaged by Verticillium dahliae Kleb. (simply, Verticillium) to determine the wavelengths of those leaves that were most responsive to cotton with Verticillium and to develop a spectral model to predict the severity levels (SLs) of Verticillium through evaluation of the SLs of cotton leaves with Verticillium at different growth stages using reflectance and the first derivative (FD) spectrum. The study revealed that the values of the physiological and biochemical parameters all gradually decreased with increasing SLs in cotton leaves infected with Verticillium. The spectral characteristics of cotton leaves infected with Verticillium were significant compared to healthy ones. The reflectance of cotton leaves increased with increasing SLs of SLs disease in the range of 400–2500 nm (excluding 700–900 nm). The values of FD spectrum changed significantly at the red edge of the chlorophyll absorption feature (680–740 nm). The wavelength position of the red edge shifted towards shorter wavelengths and the red-edge swing decreased with respect to increasing SLs. From this study, the raw spectral bands of 437–724 and 909–2500 nm and the FD spectra bands of 535–603 and 699–750 nm can be selected as sensitive bands for estimating the SLs of disease in cotton leaves. Inversion models have been established to estimate the SLs of cotton leaves infected with Verticillium. Of all models, the model of R 700nm/R 825nm was superior for quantitatively estimating the disease SLs of cotton leaves infected with Verticillium in practice: its root mean square error (RMSE) was 0.866 and relative error (RE) was only 0.012. Thus, both the selected wavelength ranges and the chosen reflectance models were good indicators of damage caused by Verticillium to cotton leaves. The results provide theoretical support for large-scale monitoring of cotton infected with Verticillium by air- and spaceborne remote sensing. 相似文献
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Red sweet peppers (Capsicum annuum) are an excellent source of essential nutrients and bioactive compounds. High hydrostatic pressures (HHP) not only increase shelf-life but also maintain nutritional and organoleptic properties better in a number of food products. The aim of this work was to measure the effect of HHP and a thermal treatment, pasteurization (PA) in a water bath at 70 °C for 10 min, on some bioactive compounds (fibre, carotenoids and antioxidant activity) and on the texture (TPA; firmness and shear force) of red Lamuyo-type sweet peppers, in order to discover the relationship between treatment (HHP and PA), tissue microstructure and bioactive compound extractability. The results show that HHP at 500 MPa and PA treatments had less impact on the microstructure, bioactive compound content (fibre and antioxidant activity) and texture of red sweet peppers, than when low pressures were used. Consequently, new functional foods could be developed using red sweet pepper tissues treated with high pressures (500 MPa) and/or PA.Industrial relevanceToday’s consumers demand foods that are rich in bioactive compounds with beneficial health effects and safer, more natural, minimally-processed food products. Red sweet peppers (Capsicum annuum) are an excellent source of essential nutrients and bioactive compounds such as carotenoids and fibre. High hydrostatic pressure (HHP) processing is considered one of the most economically viable of the non-thermal technologies that helps to preserve red sweet peppers with high nutritional and quality parameters. Therefore, it would be interesting to study the microstructure of HHP-treated red sweet pepper tissues in order to discover whether this treatment promotes the extractability of bioactive compounds, and to compare the results with those obtained by pasteurizing the red sweet pepper. Thus, these enhanced red sweet peppers could be used as ingredients in the formulation of new functional foods. 相似文献
49.
Catalytic hydrothermal liquefaction of D. tertiolecta for the production of bio‐oil over different acid/base catalysts 下载免费PDF全文
Yu Chen Yulong Wu Ranran Ding Pan Zhang Ji Liu Mingde Yang Pan Zhang 《American Institute of Chemical Engineers》2015,61(4):1118-1128
In this article, two acid catalysts (ZrO2/SO42? and HZSM‐5) and two base catalysts (MgO/MCM‐41 and KtB) were used in catalytic hydrothermal liquefaction (HTL) of Dunaliella tertiolecta (D. tertiolecta) for the production of bio‐oil. The results indicated that the acid/base property of the catalyst plays a crucial role in the catalytic HTL process, and the base catalyst is conducive to the improvement of conversion and bio‐oil yield. When KtB was used as the catalyst, the maximum conversion and bio‐oil yield was 94.84 and 49.09 wt %, respectively. The detailed compositional analysis of the bio‐oil was performed using thermogravimetric analysis, elemental analysis, FT‐IR, and GC‐MS. The compositional analysis results showed that the introduction of catalyst is beneficial for reducing the fixed carbon content in the bio‐oil, and the structure of catalyst influences on the bio‐oil composition and boiling point distribution. Based on our results and previous studies, the probable catalytic HTL microalgae model over various catalysts can be described that the main chemical reactions include ketonization, decarboxylic, dehydration, ammonolysis, and so forth. with HZSM‐5 and MgO/MCM‐41 as the catalyst; the cyclodimerization, decomposition, Maillard reaction, and ketonization are the main reactions with ZrO2/SO42? as the catalyst; the dehydration, ammonolysis, Maillard reaction, and ketonization can occur with KtB as the catalyst. Therefore, a plausible reaction mechanism of the main chemical component in D. tertiolecta is proposed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1118–1128, 2015 相似文献
50.
For the multi-item and small lot size production mode and single machine job shop scheduling sequence independent setup time, many setup times are difficult to estimate accurately, which influences the ability to achieve accurate production cycles and costs of products. The survey shows that the length of the setup time depends on the level of employee’s knowledge. Therefore, a method for determining the standard setup time quota based on the level of employees’ knowledge is proposed. First, an evaluation index system for the level of employee’s knowledge is built; the level of employee’s knowledge is estimated by the masses and experts fuzzy comprehension evaluation and entropy method. Second, the range and definition of the level of employees’ knowledge index are developed. Third, the relational model of the employee’s knowledge level and the level of employees’ knowledge index is constructed through the least squares method. Finally, an example application is presented to verify the feasibility and effectiveness of the proposed model. 相似文献