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81.
Zhen-Yu Chen Ya-Lun Su Yu-Rong Bi Suk Ying Tsang Yu Huang 《Journal of the American Oil Chemists' Society》2000,77(1):73-78
There is an increasing interest in natural antioxidants present in traditional Chinese herbal medicines. The present study
examined the antioxidant activity of heane, acetone, and methanol extracts, as well as baicalein purified from the dry roots
of Scutellaria baicalensis Georgi (common name: Huangqin), in heated canola oil. Oxygen consumption and decreases in linoleic acid linolenic acid content
were monitored in canola oil held at 90–93°C. Among the three extracts, the acetone extract was most effective against oxidation
of canola oil, followed by the methanol extract of the dry roots. The antioxidant activity of these three extracts correlated
well with their content of baicalein, which provided strong protection to canola oil from oxidation. The antioxidant activity
of Huangqin acetone extract was dose-dependent. The acetone extract at 100 ppm or above was even more effective than butylated
hydroxytoluene at 200 ppm in protecting canola oil from oxidation. The present results suggest that the acetone extract of
these roots should be further explored as a potential source of natural antioxidants for use in the processed foods. 相似文献
82.
中国沉积盆地可分为单层结构箕状断陷型,双层结构断拗型,多层结构,台,断,拗,型实践证明,不论单层,双层,多层结构含油气盆地,一般说来,箕状断陷发育的中期为主要的成油期,多层结构的含油气盆地,台型构造层发育期为最佳成气期。 相似文献
83.
Jiang-Shan Li Yifan Zhou Xin Chen Qiming Wang Qiang Xue Daniel C.W. Tsang Chi Sun Poon 《岩石力学与岩土工程学报(英文版)》2021,13(3):643-652
Management of incinerated sewage sludge ash(ISSA) and dredged contaminated marine sediments(CMSs) is a great challenge for Hong Kong and other coastal cities due to limited landfilling capacity.The present study investigates the use of high content(20% of sediment by mass) of ISSA in combination with cement/lime for solidification/stabilization(S/S) treatment of CMSs to provide a way to reuse the wastes as construction materials.The results showed that ISSA being a porous material was able to absorb a large amount of water rendering a more efficient solidification process of the marine sediment which normally had a very high water content(~80%).The S/S treatment improved the engineering properties of the sediment,but reduced the workability,especially for the lime-treated samples.Lime can be used to replace ordinary Portland cement(OPC) for better heavy metal immobilization and carbon emission reduction.The hardened sediment samples prepared with 10% of lime and 20% of ISSA could attain a strength of 1.6 MPa after 28 d of curing.In addition,leaching tests confirmed that there was no environmental risk induced by these stabilized materials.The formation of hydrated cementitious compounds including calcium silicate hydrate(C-S-H)/calcium aluminate silicate hydrate(C-A-S-H)/hydrocalumite/calcite was mainly responsible for the strength development in the ISSA/lime-treated sediments. 相似文献
84.
Nga Yi Tsang Wan-Fei Li Elizabeth Varhegyi Lijun Rong Hong-Jie Zhang 《International journal of molecular sciences》2022,23(5)
Ebola virus disease (EVD), a disease caused by infection with Ebola virus (EBOV), is characterized by hemorrhagic fever and a high case fatality rate. With limited options for the treatment of EVD, anti-Ebola viral therapeutics need to be urgently developed. In this study, over 500 extracts of medicinal plants collected in the Lingnan region were tested against infection with Ebola-virus-pseudotyped particles (EBOVpp), leading to the discovery of Maesa perlarius as an anti-EBOV plant lead. The methanol extract (MPBE) of the stems of this plant showed an inhibitory effect against EBOVpp, with an IC50 value of 0.52 µg/mL, which was confirmed by testing the extract against infectious EBOV in a biosafety level 4 laboratory. The bioassay-guided fractionation of MPBE resulted in three proanthocyanidins (procyanidin B2 (1), procyanidin C1 (2), and epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin (3)), along with two flavan-3-ols ((+)-catechin (4) and (−)-epicatechin (5)). The IC50 values of the compounds against pseudovirion-bearing EBOV-GP ranged from 0.83 to 36.0 µM, with 1 as the most potent inhibitor. The anti-EBOV activities of five synthetic derivatives together with six commercially available analogues, including EGCG ((−)-epigallocatechin-3-O-gallate (8)), were further investigated. Molecular docking analysis and binding affinity measurement suggested the EBOV glycoprotein could be a potential molecular target for 1 and its related compounds. 相似文献
85.
The past few years has seen a change in the size of newspapers, with publishers moving to a smaller size format. Five ‘standard’ newspaper sizes are used in different countries: Broadsheet, Rhensch, Tabloid, Tall Tabloid and Berliner. These papers vary in both width and height of pages and hence there are implications for human reading comfort, which may be dependent on reading location such as on a lounge chair or on a train. Experiments were carried out to determine preferences for the different sizes and to relate these preferences to the geometric characteristics of the newspapers. For both comfortable and cramped/uncomfortable reading conditions, the rank order of preference for paper types was, from least to most-preferred, Broadsheet, Rhensch, Berliner, Tall Tabloid and Tabloid. Preferences were much stronger when determined in cramped/uncomfortable reading conditions, where most comparisons were significantly different. There was good correlation between participant ratings on several scales and preference, where most factors were related to comfort of holding and controlling the paper. 相似文献
86.
W.L. Lai S.C. Kou C.S. Poon W.F. Tsang C.C. Lai 《Construction and Building Materials》2009,23(10):3152-3160
This paper reports the results of a durability study of the effects of exposing externally-bonded CFRP-concrete beams to three elevated water temperatures (25 °C, 40 °C and 60 °C). The effects of the heated water environments on the adhesive bonding layer between the CFRP and concrete beams were evaluated by quantifying: (1) the changes of delaminations within the adhesive bonding layer, (2) the changes in resistance to direct shear force and (3) the changes of failure mode distribution. Before the exposure, the condition of the adhesive bonding layer was inspected by infrared thermography (IRT). After exposure, the deterioration of the same bonding layer and failure mode distributions were measured by analyzing the visual photos on the failed CFRP strips. The failure modes were found to be affected largely by the combined effect of elevated temperature and moisture ingress, in which three types were identified: failure at concrete beams, at adhesive bonding layer and interface between CFRP strip and concrete. With these methods, results of 54 specimens show that the adhesive bonding layers of all the specimens had gradually deteriorated in the 40 °C and 60 °C water baths. This deterioration was due to the weakening of the adhesive bonding layers when the glass transition temperature (Tg) or the heat distortion temperature (HDT) was approached or even exceeded, and gradual development of delaminations at adhesive bonding layer. 相似文献
87.
Development of a re-configurable ambisonic decoder for irregular loudspeaker configuration 总被引:1,自引:0,他引:1
This study reports a heuristic genetic algorithm to determine the decoding parameters in a first-order ambisonic system for reconstructing a three-dimensional sound field with an arbitrary quad speaker configuration. On this basis, a hardware prototype has been developed using a field programmable gate array (FPGA) to decode ambisonic signals that are encoded in the standard B-format. To allow direct coupling with digital audio sources, the input and output channels of the decoder are implemented with the I2S interface. Evaluations reveal that the decoding parameters derived by this method are superior to existing approaches in terms of flexibility in loudspeaker configuration and optimisation of some of the essential factors in surround sound reconstruction. 相似文献
88.
Sitao Wu Tommy W. S. Chow Kai Tat Ng Kim Fung Tsang 《Neural computing & applications》2006,15(3-4):298-309
This paper describes an improvement of borrowing channel assignment (BCA) for patterned traffic load by using the short-term traffic prediction ability of cellular probabilistic self-organizing map (CPSOM). The fast growing cellular mobile systems demand more efficient and faster channel allocation techniques today. In case of patterned traffic load, the traditional BCA methods are not efficient to further enhance the performance because heavy-traffic cells cannot borrow channels from their neighboring cells with light or medium traffic that may have unused nominal channels. The performance can be increased if the short-term traffic load can be predicted. The predicted results can then be used for channel re-assignment. Therefore, the unused nominal channels of the light-or-medium-traffic cells can be transferred to the heavy-traffic cells that need more nominal channels. In this paper, CPSOM is used online for traffic prediction. In this sense, the proposed CPSOM-based BCA method is able to enhance the performance for patterned traffic load compared with the traditional BCA methods. Simulation results corroborate that the proposed method enables the system to work with better performance for patterned traffic load than the traditional BCA methods. 相似文献
89.
Lixin Wang Hamdi M. Manivasakan R. Tsang D.H.K. 《Communications, IEEE Transactions on》2006,54(3):518-531
The design of the medium-access control (MAC) protocol is the most crucial aspect for high-speed and high-performance local and metropolitan area networks, since the decisions made at this level determine the major functional characteristics of these networks. Most of the MAC protocols proposed in the literature are not suitable for multimedia applications, since they have been designed with one generic traffic type in mind. As a result, they perform quite well for the traffic types they have been designed for, but poorly for other traffic streams with different characteristics. In this paper, we propose an integrated MAC protocol called the Multimedia-MAC (M-MAC), which integrates different MAC protocols into a hybrid protocol in a shared-medium network to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality-of-service demands, namely, a constant-bit-rate traffic, bursty traffic (say, variable-bit-rate traffic), and emergency messages (say, control messages). We have developed a mathematical framework for the analysis and performance evaluation of our M-MAC protocol, which involves a queueing system with vacation. We have applied our M-MAC design approach to a wavelength-division multiplexing network, and evaluated its performance under various traffic conditions. 相似文献
90.