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81.
Sn5%Sb is one of the materials considered for replacing lead containing alloys for soldering in electronic packaging. We evaluated
the tensile properties of the bulk material at varied strain-rates and temperatures (to 473K) to determine the underlying
deformation mechanisms. Stress exponents of about three and seven were observed at low and high stresses, respectively, and
very low activation energies for creep (about 16.7 and 37.7 kJ/mole) were noted. A maximum ductility of about 350% was noted
at ambient temperature. Creep tests performed in the same temperature regime also showed two distinct regions, albeit with
slightly different exponents (three and five) and activation energy (about 54.4 kJ/mole). Ball indentation tests were performed
on the shoulder portions of the creep samples (prior to creep tests) using a Stress-Strain Microprobe@ (Advanced Technology Corporation) at varied indentation rates (strain-rates). The automated ball indentation (ABI) data were
at relatively high strain-rates; however, they were in excellent agreement with creep data, while both these results deviated
from the tensile test data. Work is planned to perform creep at high stresses at ambient and extend ABI tests to elevated
temperatures. 相似文献
82.
83.
本文通过分析在理想情况下不同偏振态的光经过法拉第旋转器前后Stokes矢量的变化,从理论上导出理想的光隔离器用法拉第旋转器的Mueller矩阵形式。 相似文献
84.
Beneficial effects of wettability altering surfactants in oil-wet fractured reservoirs 总被引:3,自引:0,他引:3
Subhash C. Ayirala Chandra S. Vijapurapu Dandina N. Rao 《Journal of Petroleum Science and Engineering》2006,52(1-4):261
In fractured reservoirs, an effective matrix-fracture mass transfer is required for oil recovery. Surfactants have long been considered for oil recovery enhancement, mainly in terms of their ability to reduce oil–water interfacial tension. These surfactants are effective when the fractured formations are water-wet, where capillary imbibition of surfactants from the fracture into the matrix contributes to oil recovery. However, another beneficial aspect of surfactants, namely their ability to alter wettability, remains to be explored and exploited. Surfactants capable of altering wettability can be especially beneficial in oil-wet fractured formations, where the surfactant in the fracture diffuses into the matrix and alters the wettability, enabling imbibition of even more surfactant into the matrix. This sequential process of initial diffusion followed by imbibition continues well into the matrix yielding significant enhancements in oil recovery.In order to test this hypothesis of sequential diffusion–imbibition phenomenon, Dual-Drop Dual-Crystal (DDDC) contact angle experiments have been conducted using fractured Yates dolomite reservoir fluids, two types of surfactants (nonionic and anionic) and dolomite rock substrates. A new experimental procedure was developed in which crude oil equilibrated with reservoir brine has been exposed to surfactant to simulate the matrix-fracture interactions in fractured reservoirs. This procedure enables the measurements of dynamic contact angles and oil–water interfacial tensions, in addition to providing the visual observations of the dynamic behavior of crude oil trapped in the rock matrix as it encounters the diffusing surfactant from the fractures. Both the measurements and visual observations indicate wettability alterations of the matrix surface from oil-wet to less oil-wet or intermediate wet by the surfactants. Thus this study is of practical importance to oil-wet fractured formations where surfactant-induced wettability alterations can result in significant oil recovery enhancements. In addition, this study has also identified the need to include contact angle term in the dimensionless Bond number formulations for better quantitative interpretation of rock–fluids interactions. 相似文献
85.
介绍了1套由AB公司的第5代PLC——RSLogix5000和工业PC组成的工业稳定剂间歇过程计算机控制系统。较详细地介绍系统硬件、软件的构成,ControlNet现场总线网络通信的特点,OPC数据传输的优点。同时阐述了在系统硬件设计上如何保证硬件的安全性和抗干扰问题。运行结果表明。该控制系统具有维护简单、运行可靠性高、抗干扰能力强、传输数据速度快的特点。 相似文献
86.
87.
固体酸催化合成2-乙酰噻吩 总被引:1,自引:0,他引:1
采用固体酸催化剂,以乙酸酐和精制焦化苯工艺过程中得到的浓缩噻吩为原料合成了2-乙酰噻吩。考察了固体酸催化剂用量、反应时间对噻吩转化率的影响,结果表明,含B酸和L酸中心的固体酸催化剂均能催化噻吩与乙酸酐合成2-乙酰噻吩的反应,其中CT-175树脂催化剂在常压、80℃、n(乙酸酐):n(噻吩)= 3:1的条件下,噻吩转化率达到100%。通过对固体酸催化剂HY、CT-175、MCM-41、HZSM-5、Hβ的BET、TPD表征,结果表明,酸性及孔径大小是影响噻吩乙酰化反应活性的主要因素。 相似文献
88.
89.
白豹地区延长组长6储层孔隙结构特征及影响因素分析 总被引:1,自引:0,他引:1
从储层的微观结构特征入手,应用偏光显微镜、阴极发光、扫描电镜等常规的分析研究手段,对白豹地区长6储层物性的影响因素进行了分析,认为岩石类型,云母等组分含量,粒径,硅质、碳酸盐矿物和成岩自生粘土矿物的胶结作用和溶蚀作用是影响本区长6储层发育的主要因素。 相似文献
90.
Peripheral Nerve‐Derived Matrix Hydrogel Promotes Remyelination and Inhibits Synapse Formation 下载免费PDF全文
Jian‐Long Zou Sheng Liu Jia‐Hui Sun Wei‐Hong Yang Yi‐Wei Xu Zi‐Long Rao Bin Jiang Qing‐Tang Zhu Xiao‐Lin Liu Jin‐Lang Wu Calvin Chang Hai‐Quan Mao Eng‐Ang Ling Da‐Ping Quan Yuan‐Shan Zeng 《Advanced functional materials》2018,28(13)
Regeneration of injured nerve tissues requires intricate interplay of complex processes like axon elongation, remyelination, and synaptic formation in a tissue‐specific manner. A decellularized nerve matrix‐gel (DNM‐G) and a decellularized spinal cord matrix‐gel (DSCM‐G) are prepared from porcine sciatic nerves and spinal cord tissue, respectively, to recapitulate the microenvironment cues unique to the native tissue functions. Using an in vitro dorsal root ganglion–Schwann cells coculture model and proteomics analysis, it is confirmed that DNM‐G promotes far stronger remyelination activity and reduces synapse formation of the regenerating axons in contrast to DSCM‐G, Matrigel, and collagen I, consistent with its tissue‐specific function. Bioinformatics analysis indicates that the lack of neurotrophic factors and presence of some axon inhibitory molecules may contribute to moderate axonal elongation activity, while laminin β2, Laminin γ1, collagens, and fibronectin in DNM‐G promote remyelination. These results confirm that DNM‐G is a promising matrix material for peripheral nerve repair. This study provides more insights into tissue‐specific extracellular matrix components correlating to biological functions supporting functional regeneration. 相似文献