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51.
Web service is characterized by its isomerism and loose coupling;thus greatly fa- cilitate the application of operation in distributed situation, but its disadvantages cause seri- ous safety problems. The principium and characteristic of Web service classical attack tech- nology are expatiated, classical attack techniques are classified, and attack technology is sim- ulated, and then, the directions and the future of Web security are discussed. 相似文献
52.
3.渗碳层的均匀性等离子渗碳获得的渗碳层,甚至在非平面和几何形状不规则的表面上,也是特别均匀的。在给定的条件下,可以观察到等离子体严密地包围着整个工件的表面。例如:园盘试样平面的渗碳层,虽然试样只有一个平面向着阳极,但上下两个平面的渗碳层却大致相同。在带旋转曲面的或有凹槽的表面上,渗碳层也是十分均匀的。图8表明,无 相似文献
53.
用拉伸性能相似的三种不同Al-Zn-Mg-Cu合金,研究了显微组织对裂纹扩展的影响。发现在疲劳状态和提高负荷状态,显微组织对裂纹扩展有明显的影响。通过观察断口组织,研究了裂纹扩展的微观机理。用透射电镜(TEM)研究了裂纹尖端前面的塑性区。在所有情况下,透射电镜研究揭示的裂纹扩展机理与断口观察发现的相同。与变形的拉伸试样进行比较,可以评定塑性区内的应力分布情况。该分析表明,在一个很窄的高塑性变形区后面有一个大范围的低变形区。 相似文献
54.
55.
序言铝工业趋向采用低电流密度的大型多爪头阳极,所以考虑对使用中阳极有影响的起作用的机械应力和热应力的设计因素变得更加重要。设计时应该使合成应力不超过碳块的机械强度极限,同时要使钢爪和碳块间的接触电压降为最小。 相似文献
56.
Nicoud F Castellazzi G Lesniewski PJ Thomas JC 《The Review of scientific instruments》2011,82(10):105110
Tracking of poorly defined, rotating and/or distorted objects in a video sequence poses significant problems especially in medical diagnostics including ultrasound (sonographic) video used for examination and diagnosis of internal movement of tissue or muscle and nerve action. Cross-correlation techniques have been successful in retrieving dynamic information directly from ultrasound video data. We outline a fast implementation of tracking based on normalized cross-correlation using an adaptive template and present results from our application, developed in MATLAB?, which successfully tracks arbitrarily selected objects in deformed or severely compromised images. Common ultrasound image evaluation is qualitative but there is need to retrieve quantitative dynamic information such as the trajectory or velocity of selected areas. Our approach uses normalized two-dimensional cross-correlation to find the position of an initially selected template enclosing the feature of interest and map its trajectory frame-by-frame to produce displacement and velocity plots. We illustrate operation of the application using routine ultrasound data and demonstrate its performance using test video of objects rotating full circle and rolling down a ramp. We analyse errors associated with sampling to compare performance of our implementation with a more rigorous but tedious and computationally expensive correlation of a resampled, rotated, and shifted template. 相似文献
57.
De Angeli M Castaldo C Ratynskaia S Grosso G Almaviva S Caneve L Colao F Maddaluno G 《The Review of scientific instruments》2011,82(10):106101
The scheme and construction of an electro-optical probe able to collect charge and detect optical emission from expanding dense partially ionized vapour clouds are reported. The instrument can be applied to phenomena such as dust impact ionization and solid target laser ablation. First, results of measurements of expanding plasma cloud formed upon ablating W target are presented. Use of the instrument in different experimental facilities, including tokamak, is discussed. 相似文献
58.
Influence of the land use pattern on the concentrations and fluxes of priority pollutants in urban stormwater 总被引:1,自引:0,他引:1
This paper presents the results of the concentrations (μg/L) and fluxes (g/ha) of priority substances in stormwater from three watersheds with different land use patterns (namely, residential, urban dense, high urban density). Samples were collected at the outlet of these watersheds. Thirteen chemical groups were investigated corresponding to 88 individual substances before treatment. Results showed that stormwater discharges contained 55 substances, among them some metals, organotins, PAHs, PCBs, alkylphenols, pesticides, phthalates, cholorophenols and volatile organic compounds. Therefore, stormwater was highly contaminated. However, this contamination was often comparable from site to site, since no significant difference of the pollutant load was observed between the land use patterns. 相似文献
59.
This study aimed at enhancing knowledge on the fate of diclofenac (DF), together with its main human metabolite 4'-hydroxydiclofenac (4'OHDF), during wastewater treatment by using a laboratory-scale membrane bioreactor (MBR). The reactor was fed continuously with non-radiolabelled diclofenac for a one month period prior to a single pulse of a 14C-radiolabelled solution of DF and 4'OHDF. The solution spike contained approximately 25% 4'OHDF and 65% DF, which corresponds to the ratio observed in municipal sewage, as well as traces of two other metabolites. The radioactivity was monitored for a total of twelve days in the various output streams. The calculation of the complete mass balance in the system demonstrated that the major part of the radioactivity left the reactor with the permeate (88.7%), while 2.1% was recovered in the excess sludge. Negligible amounts were recovered in the off-gas traps and on the membranes. Chromatographic analyses of effluent samples, by means of HPLC-MS coupled in parallel to a radiodetector, displayed a different pattern than the one of the spiked solution. It showed the occurrence of three additional metabolites. 相似文献
60.