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721.
Stefan Bouckaert Eli De Poorter Benôit Latré Jeroen Hoebeke Ingrid Moerman Piet Demeester 《Wireless Personal Communications》2010,53(3):443-463
Wireless sensor networks and wireless mesh networks are popular research subjects. The interconnection of both network types
enables next-generation applications and creates new optimization opportunities. However, current single-gateway solutions
are suboptimal, as they do not allow advanced interactions between sensor networks (WSNs) and mesh networks (WMNs). Therefore,
in this article, challenges and opportunities for optimizing the WSN-WMN interconnection are determined. In addition, several
alternative existing and new interconnection approaches are presented and compared. Furthermore, the interconnection of WSNs
and WMNs is used to study challenges and solutions for future heterogeneous network environments. Finally, it is argued that
the use of convergence layers and the development of adaptive network protocols is a promising approach to enable low end
devices to participate in heterogeneous network architectures. 相似文献
722.
723.
724.
Reinert ZE Musselman ED Elcock AH Horne WS 《Chembiochem : a European journal of chemical biology》2012,13(8):1107-1111
PEGged out: Poly(ethylene glycol), a simple biocompatible polymer, can replace natural loop segments in a 56-residue protein domain with a well-defined tertiary structure. Biophysical characterization of chimeras of the protein GB1 coupled with molecular dynamics simulations show that PEG enhances local backbone torsional freedom without compromising the overall protein fold or function. 相似文献
725.
Mercatelli L Sani E Giannini A Di Ninni P Martelli F Zaccanti G 《Nanoscale research letters》2012,7(1):96
The full characterization of the optical properties of nanofluids consisting of single-wall carbon nanohorns of different
morphologies in aqueous suspensions is carried out using a novel spectrophotometric technique. Information on the nanofluid
scattering and absorption spectral characteristics is obtained by analyzing the data within the single scattering theory and
validating the method by comparison with previous monochromatic measurements performed with a different technique. The high
absorption coefficient measured joint to the very low scattering albedo opens promising application perspectives for single-wall
carbon nanohorn-based fluid or solid suspensions. The proposed approximate approach can be extended also to other low-scattering
turbid media. 相似文献
726.
727.
In this paper, we study a mixed-mode fracture process using a conventional two dimensional lattice model with incorporated
meso-level internal material structure. Simple elasto-brittle elements of the network are divided into three phases according
to a projected grain layout. The stiffness of any element that fulfils a failure criterion is removed. As a new feature of
the otherwise standard lattice approach, we added the recovery of normal stiffness when a severed element enters the compressive
regime. This enhancement enables capture of the shear resistance of an existing crack caused by crack roughness, i.e. what
is termed aggregate interlocking. We demonstrate this enhancement via the simulation of mixed-mode experiments on concrete
performed at a laboratory at the Technical University of Denmark. Double notched concrete specimens were initially pre-cracked
in tension. Then, various combinations of tensile and shear load (normal and tangential to the crack plane) were applied.
Simulated crack patterns and load–displacement curves are compared to the experimental observations. 相似文献
728.
Mlawer EJ Payne VH Moncet JL Delamere JS Alvarado MJ Tobin DC 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2012,370(1968):2520-2556
Water vapour continuum absorption is an important contributor to the Earth's radiative cooling and energy balance. Here, we describe the development and status of the MT_CKD (MlawerTobinCloughKneizysDavies) water vapour continuum absorption model. The perspective adopted in developing the MT_CKD model has been to constrain the model so that it is consistent with quality analyses of spectral atmospheric and laboratory measurements of the foreign and self continuum. For field measurements, only cases for which the characterization of the atmospheric state has been highly scrutinized have been used. Continuum coefficients in spectral regions that have not been subject to compelling analyses are determined by a mathematical formulation of the spectral shape associated with each water vapour monomer line. This formulation, which is based on continuum values in spectral regions in which the coefficients are well constrained by measurements, is applied consistently to all water vapour monomer lines from the microwave to the visible. The results are summed-up (separately for the foreign and self) to obtain continuum coefficients from 0?to 20?000?cm(-1). For each water vapour line, the MT_CKD line shape formulation consists of two components: exponentially decaying far wings of the line plus a contribution from a water vapour molecule undergoing a weak interaction with a second molecule. In the MT_CKD model, the first component is the primary agent for the continuum between water vapour bands, while the second component is responsible for the majority of the continuum within water vapour bands. The MT_CKD model should be regarded as a semi-empirical model with strong constraints provided by the known physics. Keeping the MT_CKD continuum consistent with current observational studies necessitates periodic updates to the water vapour continuum coefficients. In addition to providing details on the MT_CKD line shape formulation, we describe the most recent update to the model, MT_CKD_2.5, which is based on an analysis of satellite- and ground-based observations from 2385 to 2600?cm(-1) (approx. 4?μm). 相似文献
729.
C_(22)-三元酸三酯的合成 总被引:1,自引:0,他引:1
C22-三元酸三酯的合成以棉籽油甲酯为原料,将非共轭的亚油酸甲酯在催化剂作用下转化成共轭亚油酸甲酯,同时与富马酸二酯发生D iels-A lder反应,生成C22-三元酸三酯。采用正交实验设计探讨了C22-三元酸的甲基二异戊酯的投料比、温度、催化剂用量、反应时间对合成反应的影响。富马酸二酯加入量按照富马酸二酯∶亚油酸甲酯(摩尔比)=1.1∶1投料,反应温度选择在200~210℃,催化剂碘的用量在0.6%,反应控制在2 h,最佳转化率相对于亚油酸甲酯可达96%。 相似文献
730.
聚乙二醇单甲醚丙烯酸酯是合成梳形分散剂的重要单体。以聚乙二醇单甲醚和丙烯酸为原料,对甲苯磺酸为催化剂,减压条件下直接酯化合成聚乙二醇单甲醚丙烯酸酯,采用傅立叶红外光谱表征产物结构。对反应条件进行了优化,结果表明,在温度90 ℃、压力0.06 MPa、催化剂用量为反应物总质量的2.0%、阻聚剂用量为丙烯酸质量的1.5%、丙烯酸与聚乙二醇单甲醚物质的量比3∶1和反应时间5 h条件下,酯化率可达92.6%。高效液相色谱分析证明,用饱和食盐水和乙酸乙酯萃取后的产物纯度为99.2%。 相似文献