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101.
邻氟苯甲腈的合成研究   总被引:6,自引:0,他引:6  
以邻甲苯胺为原料 ,采用四步反应法合成邻氟苯甲腈。 (1)邻甲苯胺经西曼反应合成邻氟甲苯 ,收率 6 5 % ;(2 )邻氟甲苯经氯化、水解得到邻氟苯甲醛 ,以过氧化苯甲酰为氯化引发剂 ,氧化锌为水解催化剂 ,收率 80 % ;(3)邻氟苯甲醛经肟化反应得到邻氟苯甲醛肟 ,收率 87% ;(4)肟用乙酸酐脱水合成出邻氟苯甲腈 ,收率 76 % ,产品质量分数大于 99%。  相似文献   
102.
焙烧硫酸铁铵催化合成季戊四醇双缩苯甲醛   总被引:1,自引:0,他引:1  
以硫酸铁铵经600℃高温焙烧制得一类新型固体酸催化剂,该催化剂在合成季戊四醇双缩苯甲醛中具有较高的催化活性,其优化条件是:苯甲醛与季戊四醇物质的量比为2.0:1,催化剂用量为5%(以醇的质量为准),回流温度83℃,反应时间2.5h,在此优化条件下,反应产率为87%。且催化剂容易制备,可连续使用。  相似文献   
103.
国外ABS生产技术进展   总被引:4,自引:0,他引:4  
综述了世界ABS树脂的生产及供求,介绍了各种生产工艺的进展,对其技术特点及产品性能进行了比较。  相似文献   
104.
A novel and effective protocol for the preparation of superparamagnetic immunomicrospheres has been developed. First, micro‐size magnetic poly (methacrylate‐divinylbenzene) (PMA‐DVB) spheres were prepared by a modified suspension polymerization method. The oleic acid coated magnetite (Fe3O4) nanoparticles made by coprecipitation were mixed with monomers of MA, DVB, and initiator benzoyl peroxide (BPO) to form oil in water emulsion droplets with the presence of poly (vinyl alcohol) (PVA‐1788) as a stabilizer. The polymerization reaction was carried out in a 2‐L beaker equipped with four vertical stainless steel baffleplates by increasing the temperature of the mixture at a controlled rate. The resulting magnetic microspheres are micro‐sized (less than 8μm in diameter) and 80 percent of them are in the size ranging from 1 to 5 μm. Then, they were highly functionalized via ammonolysis reaction with ethylenediamine, and the surface amino‐modified magnetic microspheres were obtained. The morphology and properties of these magnetic microspheres were examined by SEM, TEM, VSM, and FT‐IR. Affinity ligand protein A (ProtA) was covalently immobilized to the amino‐modified magnetic microspheres by the glutaraldehyde method. These ProtA‐immobilized magnetic immunomicrospheres were effective for affinity bioseparation processes, as was demonstrated by the efficient immunoaffinity purification of antibodies IgG2a (22mg per gram of microspheres) from mouse ascites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2205–2211, 2004  相似文献   
105.
介绍了无汞锌粉中的杂质、析气量、锌粉形貌以及电池密封圈对无汞碱性电池高温贮存性能的影响,探讨了电池漏液的原因,提出了防止漏液的措施。  相似文献   
106.
Completely biodegradable foams of poly(propylene carbonate) (PPC) derived from carbon dioxide and propylene oxide were fabricated using N, N′-dinitroso pentamethylene tetramine (DPT) as chemical blowing agent, and urea as the activator to lower the decomposition temperature of DPT. Thermal decomposition behavior and gas evolution behavior of the DPT composite with various urea to DPT ratios were investigated to optimize the composition of the blowing agent. The formulation of blowing agent mixture and foaming condition, the foam morphologies, the molecular weight change, as well as the mechanical properties of produced PPC foams were studied extensively. The experimental results demonstrated that the greatest blowing ratio of 14.8 can be afforded in case 12 phr blowing agent was used at 170 °C for 30 min. Gel permeation chromatography (GPC) and thermal analysis revealed that DPT acted as both chain-extension agent and blowing agent for PPC matrix. The molecular weight of PPC subjected to foaming increased by 76%. The foamed PPC exhibited superior mechanical properties and can be used as packaging material for many practical applications.  相似文献   
107.
An O?carboxymethylated chitosan (O? CMCh) water solution (I) and N,N‐dimethylacetamide (DMAc) emulsion (II) were blended with a cellulose LiCl/DMAc solution, and corresponding polyblends (Polyblends I and II) were obtained. The rheology of the three fluids, that is, the cellulose solution and Polyblends I and II, was investigated. The cellulose solution was characterized by a power‐law fluid. When an O‐CMCh water solution or DMAc emulsion was added to the cellulose solution, the power‐law curve was preserved. The power‐law indexes (n) of all three fluids increased along with the temperature. Polyblend I displays an n close to but a little higher than that of the cellulose solution, while Polyblend II shows a much higher power index than those of the other two fluids. The values of the apparent viscosity (ηa) for all the three fluids are close and decrease along with an increase in the temperature. Adding O‐CMCh microparticles into Polyblends I and II results in a decrease in the structural viscosity index (Δη) in comparison to that of the cellulose solution, and this effect is very obvious for Polyblend I. A cellulose solution's Δη declines with the augmentation of temperature, while the Δη's of both Polyblends I and II show minimum values at about 323 K. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1719–1725, 2003  相似文献   
108.
Dynamic images that possess beauty and are user-friendly can increase the use of digital technology. In addition to information conveyance, dynamic images also act as a communication bridge in the human–machine interface. Dynamic images are widely used in the application of digital media. Therefore, understanding the visual effects of dynamic images on viewers is a very important issue. From a visual communication design perspective, dynamic images influence not only image quality, but also the viewers’ perception and impression of the displayed image. In the contemporary age characterized by universal usage of dynamic images, designers should attain synchronized knowledge and understanding of relevant media technology so as to present preferred design quality in the management of digital design such as animation design, Web page design, multimedia design, and so on. The current study noted that psychological effects such as viewers’ visual attention, preferences, and understanding were more important than image quality. Therefore, this study adopted the viewpoint of “visual design” and conducted a perceptual evaluation of grating frequency and grating velocity. The pair-comparison method and scale method were adopted in the research methodology to simplify perceptual evaluations and enhance their validity. The purpose of this study was: (1) To propose recommendations for displaying dynamic images and improving image performance using perceptual evaluation methods. (2) To examine the influence of psychological factors on viewer’s comfort when they experience dynamic images. (3) To identify the best grating feature combinations that meet viewer’s psychological characteristics and propose recommendations for dynamic images design. The study concludes that it is useful to establish criteria for evaluating users’ perception and to, develop perceptual evaluations of dynamic images. It is recommended that designers find a balance between watching a moving imaging display “clearly” and watching it “comfortably” for successful reception by the viewer.  相似文献   
109.
In this article, the polarization ratio (PR) of TerraSAR-X (TS-X) vertical–vertical (VV) and horizontal–horizontal (HH) polarization data acquired over the ocean is investigated. Similar to the PR of C-band synthetic aperture radar (SAR), the PR of X-band SAR data also shows significant dependence on incidence angle. The normalized radar cross-section (NRCS) in VV polarization data is generally larger than that in HH polarization for incidence angles above 23°. Based on the analysis, two PR models proposed for C-band SAR were retuned using TS-X dual-polarization data. A new PR model, called X-PR hereafter, is proposed as well to convert the NRCS of TS-X in HH polarization to that in VV polarization. By using the developed geophysical model functions of XMOD1 and XMOD2 and the tuned PR models, the sea surface field is retrieved from the TS-X data in HH polarization. The comparisons with in situ buoy measurements show that the combination of XMOD2 and X-PR models yields a good retrieval with a root mean square error (RMSE) of 2.03 m s–1 and scatter index (SI) of 22.4%. A further comparison with a high-resolution analysis wind model in the North Sea is also presented, which shows better agreement with RMSE of 1.76 m s–1 and SI of 20.3%. We also find that the difference between the fitting of the X-PR model and the PR derived from TS-X dual-polarization data is close to a constant. By adding the constant to the X-PR model, the accuracy of HH polarization sea surface wind speed is further improved with the bias reduced by 0.3 m s–1. A case acquired at the offshore wind farm in the East China Sea further demonstrates that the improvement tends to be more effective for incidence angles above 40°.  相似文献   
110.
对胺烷基化聚羟基酸酰胺的合成方法进行研究,确立了反应条件与制得的聚羟基酸酯特征之间的一些相互关系。并为获得适当长度的聚酯链选择了最佳合成条件。同时扼要论述了这类超分散剂的结构特性,以及对于颜料粒子表面吸附作用、分散体系的稳定作用以及对涂料、油墨生产的重要意义。  相似文献   
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