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51.
52.
Shaofeng Wang Jianwei Xu Yuejin Tong Lin Wang Chaobin He 《Polymer International》2005,54(9):1268-1274
A novel cholesterol‐imprinted polymer (CMIP‐H) was prepared by a hybrid method of covalent imprinting and non‐covalent imprinting. This approach involves the copolymerization of a template‐containing monomer, cholesteryl 2‐hydroxyethyl methacrylate carbonate, and a cross‐linker, followed by hydrolysis to afford a flexible guest‐binding site accompanied with the easy and efficient removal of a ‘sacrificial spacer’. The effect of solvent on the binding capacity of CMIP‐H towards cholesterol was studied, indicating that a good binding capacity towards cholesterol could be achieved in a less‐polar solvent. The binding experiments of CMIP‐H towards a series of structural analogues of cholesterol, including cholesterol acetate, progesterone and stigmasterol, were carried out in hexane. The results showed that CMIP‐H almost did not bind cholesterol acetate at all because the hydrogen‐bonding site is blocked. It exhibited a similar binding towards both cholesterol and stigmasterol, but much higher binding towards progesterone. Copyright © 2005 Society of Chemical Industry 相似文献
53.
彩色地震剖面显示是地震剖面显示技术中较为先进的一种显示方式.它具有常规黑白显示剖面所无法比拟的优点.尤其是在一些特殊处理显示的剖面(诸如三瞬剖面、虚速度测井剖面以及烃类显示剖面)中,这些剖面给人以清晰直观和一目了然的感觉.但是,目前彩色剖面在国内尚未得到普遍地应用,其原因之一是由于彩色显示处理要求计算机具有大的内存容量和高速运算等方面的性能,所以一般都是在大中型计算机上处理.而小型计算机由于内存容量和运算速度等面存在着不足,所以难以运行象现今国内所使用的UNIRAS这样庞大的系统.笔者在研究了UNIRAS系统的实现原理后,另辟蹊径,在只有32k内存容量又无虚拟存贮管理系统的TEMPUSⅡ小型计算机上,采用光栅处理技术,实现了地震剖面彩色显示,并取得了令人满意的结果. 相似文献
54.
在第一部分综合讨论的基础上对甘三酯立体专一分析方法作了初步探讨。以液体油(菜油)及固体脂(猪脂)为基质,系统地研究了这一分析方法,取得了经验并补充了一些具体验证方法。分析液体油的结果与文献数据相一致,分析猪脂的结果欠佳,还存在一些问题需待进一步研究。 相似文献
55.
Zirconium(IV) tungstoiodophosphate has been synthesized under a variety of conditions. The most chemically and thermally stable
sample is prepared by adding a mixture of aqueous solutions of 0·5 mol L−1 sodium tungstate, potassium iodate and 1 mol L−1 orthophosphoric acid to aqueous solution of 0·1 mol L−1 zirconium(IV) oxychloride. Its ion exchange capacity for Na+ and K+ was found to be 2·20 and 2·35 meq g−1 dry exchanger, respectively. The material has been characterized on the basis of chemical composition, pH titration, Fourier
transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the exchange capacity of drying the exchanger
at different temperatures has been studied. The analytical importance of the material has been established by quantitative
separation of Pb2+ from other metal ions. 相似文献
56.
Jonathan P. Belnoue Giang D. Nguyen Alexander M. Korsunsky 《International Journal of Fracture》2007,144(1):53-60
This paper presents a new 1-D non-local damage-plasticity deformation model for ductile materials. It uses the thermodynamic
framework described in Houlsby and Puzrin (2000) and holds, nevertheless, some similarities with Lemaitre’s (1971) approach.
A 1D finite element (FE) model of a bar fixed at one end and loaded in tension at the other end is introduced. This simple
model demonstrates how the approach can be implemented within the finite element framework, and that it is capable of capturing
both the pre-peak hardening and post-peak softening (generally responsible for models instability) due to damage-induced stiffness
and strength reduction characteristic of ductile materials. It is also shown that the approach has further advantages of achieving
some degree of mesh independence, and of being able to capture deformation size effects. Finally, it is illustrated how the
model permits the calculation of essential work of rupture (EWR), i.e. the specific energy per unit cross-sectional area that
is needed to cause tensile failure of a specimen. 相似文献
57.
Yewang Su Baohua Ji Yonggang Huang Kehchih Hwang 《Journal of Materials Science》2007,42(21):8885-8893
Wet adhesion is widely adopted in biological adhesion systems in nature. Wet adhesion is studied in this paper with the focus
on the effect of different contact shapes (flat, concave, convex, and ring-like) on the adhesion force. The evolution of the
liquid bridge between a fiber tip and substrate during the detaching process shows two transition points. The first transition
from the radius-controlled to the contact-angle controlled process is critical to influence the strength and robustness of
adhesion. We show that a concave shape is more effective than a flat one, while a convex shape has no advantage. A ring-like
contact shape has advantages in a hydrophobic environment and on a rough surface. 相似文献
58.
Irine Banu Lucy 《Journal of Materials Science》2007,42(14):5875-5879
Capacitance and dielectric loss measurements were carried out using an Al/Cu–GeO2/Al sandwich structure for 0 to 10 vol% Cu films, 120–400 nm thick, deposited at 0.4–1.5 nm/s in the frequency and temperature
range 1–106 Hz and 90–573 K, respectively. The variation of capacitance and dielectric loss with frequency and temperature follows the
Goswami and Goswami model. Capacitance decreases slowly with increasing thickness and also varies with the change in deposition
rate of the cermet film. 相似文献
59.
V. Thomas Paul S. Saroja P. Hariharan A. Rajadurai M. Vijayalakshmi 《Journal of Materials Science》2007,42(14):5700-5713
This paper presents the results of a study on the microstructural and microchemical variations in a multipass Gas Tungsten
Arc weld (GTAW) of modified 9Cr-1Mo steel. The changes brought about in the steel due to the heating and cooling cycles during
welding and the subsequent effects due to reheating effects during multipass welding are described. Detailed analytical transmission
electron microscopy has been carried to study the type and composition of the primary and secondary phases in this steel.
The systematic changes in microstructural parameters such as Prior Austenite Grain Size, martensite lath size, number density,
size and microchemistry of carbides, have been understood based on the different transformations that the steel undergoes
during the heating and cooling process. Based on the observed microstructure, an attempt has been made to identify distinct
microstructural zones and possible thermal cycles experienced by different regions of the weldment. 相似文献
60.
Nina Georgieva Kostova Elka Kraleva Alla A. Spojakina Erika Godocikova Peter Balaz 《Journal of Materials Science》2007,42(10):3321-3325
The Al-MCM-41 has been used as support to prepare Mo-containing catalysts. The 12- molybdophosphoric heteropoly acid (HPMo)
is used as initial compound. The catalysts are synthesized by two different methods: incipient impregnation with aqueous solution
of the acid and mechanochemical synthesis. The samples were tested in the reaction of the thiophene hydrodesulfurization after
activation with mixture H2 + H2S. The effect of the preparation method of the catalysts on their physicochemical and catalytic properties has been studied.
A partial destruction of the loaded compound is observed in mechanochemically treated sample whereas the aggregates are formed
from the particles of different size in the impregnated sample. The specific surface area of the sample prepared by mechanical–chemical
treatment decreases 2–3 times, while the total pore volume is about four times lower. The HDS activity is higher on the impregnated
sample than on the mechanochemically treated one. 相似文献