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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
861.
862.
Preparation of carbon
nanotubes/hydrogenated nitrile rubber composite by ultrasonic technique 总被引:1,自引:0,他引:1
将低相对分子质量的液体氢化丁腈橡胶(HNBR)溶于丙酮溶剂中,加入碳纳米管,用超声波技术制备了液体HNBR与碳纳米管的复合母料,然后再与HNBR混炼、硫化,获得碳纳米管/HNBR复合材料.结果表明,碳纳米管在HNBR中分散性好,对HNBR有较好的增强性,但在后期机械加工中产生了断裂. 相似文献
863.
864.
Boon-Seang Chu Sosaku Ichikawa Sumiyo Kanafusa Mitsutoshi Nakajima 《Journal of the American Oil Chemists' Society》2007,84(11):1053-1062
This work was initiated to prepare protein-stabilized β-carotene nanodispersions using emulsification–evaporation. A pre-mix
of the aqueous phase composed of a protein and hexane containing β-carotene was subjected to high-pressure homogenization
using a microfluidizer. Hexane in the resulting emulsion was evaporated under reduced pressures, causing crystallization and
precipitation of β-carotene inside the droplets and formation of β-carotene nanoparticles. Sodium caseinate (SC) was the most
effective emulsifier among selected proteins in preparing the nanodispersion, with a monomodal β-carotene particle-size distribution
and a 17-nm mean particle size. The results were confirmed by transmission-electron microscopy analysis. SC-stabilized nanodispersion
also had considerably high ζ-potential (−27 mV at pH 7), suggesting that the nanodispersion was stable against particle aggregation.
Increasing the SC concentration decreased the mean particle size and improved the polydispersity of the nanodispersions. Nanodispersions
prepared with higher β-carotene concentrations and higher organic-phase ratios resulted in larger β-carotene particles. Although
increased microfluidization pressure did not decrease particle size, it did improve the polydispersity of the nanodispersions.
Repeating the microfluidization process at 140 MPa caused the nanodispersions to become polydisperse, indicating the loss
of emulsifying capacity of SC due to protein denaturation. 相似文献
865.
The objective of this work is to study the transfer of oxygen from gas to liquid phase in an electroflotation cell. The measurements
were performed in a laboratory scale cell using insoluble electrodes, titanium coated with ruthenium oxide as anode and stainless
steel as cathode. The volumetric mass transfer coefficient K
L
a, was characterized for clean tap water as liquid phase for different values of current density (J). The global coefficient
of mass transfer based on the liquid film, K
L
, and the specific interfacial area, a, were characterized. A model which relates K
L
a to current density was established. Different evaluation criteria of oxygen transfer in electroflotation process were determined
and compared with other aeration process. 相似文献
866.
尿素装置液相浓度在线自动检测软件的研究 总被引:1,自引:1,他引:1
为了改善尿素装置先进的控制和落后的人工检测物料浓度之间的矛盾,运用化工热力学原理,以及热力学模型组合求解法,研制了液相浓度实时检测软件。并开发了多种软件以适应各类尿素流程(水溶液全循环法、CO2汽提法、氨汽提法)的需要 相似文献
867.
Xingsen Gao Junmin Xue John Wang Ting Yu Ze Xiang Shen 《Journal of the American Ceramic Society》2003,86(5):791-794
0.6Pb(Ni1/2 W1/2 )O3 ·0.4PbTiO3 (0.6PNW·0.4PT) of complex perovskite structure is successfully synthesized by mechanical activation of mixed oxide composition, followed by sintering at 950°C. It exhibits a considerably stable temperature dependence of dielectric constant over the wide temperature range of −120° to 20°C, although there occurs a dielectric peak at around 74°C. Raman spectroscopic studies show the coexistence of tetragonal and pseudocubic perovskite phases on sintering at 950°C, which are attributed to the inhomogeneous distribution of PbTiO3 arising from mechanical activation. The dielectric behavior can be fine tuned by thermal annealing at 750°C, leading to phase redistribution in PNW-PT. 相似文献
868.
Jose Gerde Connie Hardy Walter Fehr Pamela J. White 《Journal of the American Oil Chemists' Society》2007,84(6):557-563
Two extruded-expelled physically refined soybean oils with reduced contents of linolenic acid, ultra-low- linolenic acid (ULL,
1.5%) and low-linolenic acid (LL, 2.6%), and a extruded-expelled physically refined control oil (control, 5.3% linolenic acid)
were evaluated by frying French fries in a commercial-like setting for 6 h day−1 during 23 days. The oils became darker, increased in yellow color at the beginning, and became redder and less green throughout
the process. Free fatty acids levels were not different among the oils until day 14, after which, ULL was different from the
control for the remainder of frying. The conjugated dienoic acid values were greatest in the control. Generally, ULL and LL
oils had lower percentages of polar compounds than did the control, providing a frying life 2 days longer than the control
and ~30% increase in frying time. A trained sensory panel evaluated the French fries on days 2, 5, and 6. Buttery and potato
flavors decreased, and rancid and painty flavors increased over frying time for all products. Rancid flavor was highest in
the fries from the control oil. Overall, the ULL and LL oils performed better than did the control oil and ULL tended to perform
better than the LL. 相似文献
869.
Raúl Quijada Juan Luis Guevara Mehrdad Yazdani-Pedram Griselda B. Galland Daniel Ribeiro 《Polymer Bulletin》2002,49(4):273-280
Summary
1-Octadecene (C18) was polymerized by using different metallocene catalysts. The rac-Et(Ind)2ZrC12/MAO (I) and rac-Me2Si(Ind)2ZrC12/MAO (III) presented the highest activity as compared with ra-Et(2-Me-Ind)2ZrCl2/MAO (II) and Ph2C(Flu)(Cp)ZrC12/MAO (IV) catalysts. Catalyst IV produced polymers with highest molecular weights. The microstructure of the polymers was
determined by 13C-NMR spectroscopy. Catalyst systems I, II and III produced isotactic polymers while catalyst IV produced polymers with mainly
syndiotactic structures but with large amount of stereoregular error.
Received: 21 June 2002/Revised version: 4 November 2002/ Accepted: 4 November 2002 相似文献
870.
水泥基复合材料纳米化改性的研究 总被引:5,自引:0,他引:5
水泥基材料中70%为纳米尺度的C—S—H凝胶,因此对水泥基材料进行纳米改性具有很好的基础,我国有一些关于纳米基材料在混凝土中应用的研究,但目前还不可能在实体工程中采用这种混凝土。纳米在水泥科技中的应用应首先是纳米技术与一些技术含量高的水泥基复合材料的结合。研制具有超高性能(力学)以及特定功能的纳米水泥基复合材料是目前水泥基材料纳米化改性的研究方向。 相似文献