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排序方式: 共有3371条查询结果,搜索用时 15 毫秒
1.
G. Murali Dhar B. N. Srinivas M. S. Rana Manoj Kumar S. K. Maity 《Catalysis Today》2003,86(1-4):45-60
Support effects form important aspect of hydrodesulfurization (HDS) studies and mixed oxide supports received maximum attention in the last two decades. This review will focus attention on studies on mixed oxide supported Mo and W catalysts. For convenience of discussion, these are divided into Al2O3 containing mixed oxide supports, TiO2 containing mixed oxide supports, ZrO2 containing mixed oxide supports and other mixed oxide supports containing all the rest. TiO2 containing mixed oxides received maximum attention, especially TiO2–Al2O3 supported catalysts. A brief discussion about their prospects for application to ultradeep desulfurization is also included. An overview of the available literature with emphasis on research carried out in our laboratory form the contents of this publication. 相似文献
2.
Kwang-Hee Lim 《Korean Journal of Chemical Engineering》2005,22(2):228-233
An experiment for five stages of a biofilter-run was performed to investigate the effect of hydrophilic ethanol and hydrophobic
toluene on the biodegradation of hydrophobic toluene and hydrophilic ethanol, respectively, when waste-air containing toluene
and ethanol was treated by a biofilter. Removal efficiencies of toluene and ethanol began to decrease when inlet load surpassed
90 g/m3/h and 100 g/m3/h consistent with maximum elimination capacities of toluene and ethanol, respectively. At the end of the biofilter-run, removal
efficiencies for toluene and ethanol were decreased and maintained at 65% and 40%, respectively. The concentration of toluene
at 1st sampling port was raised by factor of two in the 3rd stage of the biofilter run when the inlet load of ethanol co-feed
was increased by 1.5 times, while the process conditions of toluene were maintained the same as those of the 2nd stage of
biofilter-run. According to the result of Mohseni and Allen, it may be interpreted that removal efficiency of hydrophobic
toluene was affected by the presence of hydrophilic ethanol when high load of hydrophobic toluene was applied like that of
the 1st sampling port of the biofilter. However it was not the case when a low load of hydrophobic toluene was applied like
those of the 2nd, 3rd and 4th sampling ports since hydrophobicity of toluene is much less that of α-pinene. Thus, it may be
suggested that biodegradation of hydrophobic VOC was interfered by hydrophilic VOC dissolved in the biolayer and the degree
of interference was proportional to the inlet load of hydrophobic VOC as well as that of hydrophilic VOC and was inversely
proportional to the solubility of hydrophobic VOC. However, it was inferred that the existence of hydrophobic toluene from
waste-air can hardly inversely hinder the removal of hydrophilic ethanol in the biofilter when timeevolutions of hydrophilic
ethanol concentrations of this experiment were compared with those of the previous experiment of biofilter to treat waste-air
containing ethanol only. 相似文献
3.
4.
Ashraf Ayoub 《Computers & Structures》2003,81(7):411-421
This paper presents an inelastic element for the analysis of beams on foundations. The element is derived from a two-field mixed formulation with independent approximation of forces and displacements. The state determination algorithm for the implementation of the element in a general purpose nonlinear finite element analysis program is presented and its stability characteristics are discussed. Numerical studies are performed to compare the model with the classical displacement formulation. The studies confirm the superiority of the proposed model in describing the inelastic behavior of beams on foundations. 相似文献
5.
多功能滚齿机的数字控制系统 总被引:1,自引:1,他引:0
本文叙述了以STDPC/XT(或PC/AT)机为主要核心构成的滚齿机数字控制系统的结构,软件设计和特点,系统采用混合语言编程,极大地提高了软件设计的灵活性与快速性,也分析了CNC系统的加工过程,提出了加工中的软件预处理控制方法,并给出了轴伺服控制的并行算法分析与实现。 相似文献
6.
We have studied the CO2/CH4 mixed gas permeation through hollow fiber membranes in a permeator. An approach to characterize the true separation performance of hollow fiber membranes for binary gas mixtures was provided based on experiments and simulations. Experiments were carried out to measure the retentate and permeate flow rates and compositions at each outlet. The influences of pressure drop within the hollow fibers, non-ideal gas behavior in the mixture and concentration polarization were taken into consideration in the mathematics model. The calculation results indicate that the net influence of the non-ideal gas behavior, competitive sorption and plasticization yields the calculated CO2 permeance in a mixed gas permeator close to that obtained in pure gas tests. Whereas the CH4 permeance is higher in the mixed gas tests than that in the pure gas tests, as the plasticization caused by CO2 dominates the permeation process. As a result, the CO2/CH4 mixed gas selectivity is smaller than those obtained in pure gas tests at equivalent pressures.The calculated membrane performance shows little changes with stage cut if the effect of concentration polarization is accounted for in the calculation. The integration method developed in this study could provide more accurate characterizations of mixed gas permeance of hollow membranes than other estimation methods, as our model considers the roles of non-ideal gas behavior and concentration polarization properly. 相似文献
7.
胜利油田东营深层盐膏地层发育,盐膏段厚度大,分布范围广,地层岩性十分复杂,钻井中经常发生喷、漏、塌、卡,遇阻、划眼、电测遇阻等井下复杂事故。郝科1井是在该区设计的一口重点深探井,宅钻井深5807.81m,井底最高温度230℃。介绍了深层盐膏层钻井液体系的转化工艺、性能控制、维护处理、防漏、堵漏、固相控制、抗污染和钻具缓蚀等技术,以及MMH聚合物饱和盐水钻井液在郝科1井的成功应用。结果表明,该钻井液在高密度下对盐膏层具有较强的抑制性、悬浮携砂性和抗污染性,抗温220—230℃。MMH聚合物饱和盐水钻井液体系及其配套技术满足了深层盐膏层钻井施工需要。 相似文献
8.
M WünschB.A Wolf 《Polymer》2002,43(18):5027-5034
Vapor pressures, phase equilibria and interfacial tensions σ were measured for solutions of poly(dimethylsiloxane) (PDMS, Mw[equals]75 kg/mol and Mn[equals]50 kg/mol) in mixed solvents of toluene (TL) and ethanol (EtOH) at 30, 40, 50 and 60 °C. The experimental ternary phase diagrams can be modeled quantitatively from the determined concentration and temperature dependent binary interaction parameters χij if the experimentally inaccessible composition dependence of χEtOH/PDMS is adjusted. The relations between σ and the equation of state of the system differ from that applying to single solvents. The exponents as well as the amplitude prefactors of the corresponding scaling laws (e.g. the dependencies of σ on the length of the tie lines or on the hump energy, i.e. on the intrusion into the two phase regime quantified in terms of Gibbs energies) change considerably with temperature. However, this variation can be reduced significantly by normalizing the independent variables. Dividing the length of the tie lines by the length for the corresponding binary subsystem proves more efficient than the distance of these tie lines from the critical point of the ternary system relative to the maximum distance of the binary subsystem. A combined normalization does not improve the situation. 相似文献
9.
R. Dula R. Janik T. Machej J. Stoch R. Grabowski E.M. Serwicka 《Catalysis Today》2007,119(1-4):327-331
Mg/Mn/Al mixed oxide systems of similar atomic ratios close to 2/0.5/1 were obtained by calcination of Mg,Al layered double hydroxide (LDH) type precursors containing Mn either in the cationic form within the brucite layer or as permanganate anions in the interlayer. The materials were characterised with PXRD, thermal analysis, XPS, ESR, TPR and BET. In mixed oxides derived from interlayer-doped precursor PXRD identified MgO–MnO solid solution and poorly crystalline Al-rich spinel phase, while those obtained from layer-doped LDH contained a better crystalline Mn-rich spinel. Surface of both materials was covered with poorly crystalline and/or amorphous Mn4+-containing phases. Higher reducibility of this surface coat in calcined layer-doped catalyst, as compared to interlayer-doped one, was attributed to the differences in the nature of underlying crystalline phases, and was considered the chief reason for the higher catalytic activity of this catalyst in the total oxidation of toluene. 相似文献
10.
该文分析了应用袋装炸药装填水孔爆破产生拒爆、"冲天炮"、根底偏高和爆破效果差等问题,然而应用乳化炸药混装车装填水孔可以解决这些问题,并且爆破后具有根底平整、大块率低、毒气少和综合效益高等优点.以三峡永久船闸旁侧泄水箱涵工程和江苏田湾核电站工程为例进行了分析. 相似文献