全文获取类型
收费全文 | 1281篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 214篇 |
金属工艺 | 44篇 |
机械仪表 | 49篇 |
建筑科学 | 9篇 |
矿业工程 | 24篇 |
能源动力 | 10篇 |
轻工业 | 12篇 |
水利工程 | 17篇 |
石油天然气 | 78篇 |
无线电 | 111篇 |
一般工业技术 | 374篇 |
冶金工业 | 205篇 |
原子能技术 | 78篇 |
自动化技术 | 49篇 |
出版年
2022年 | 16篇 |
2020年 | 17篇 |
2019年 | 23篇 |
2018年 | 48篇 |
2017年 | 51篇 |
2016年 | 52篇 |
2015年 | 18篇 |
2014年 | 28篇 |
2013年 | 57篇 |
2012年 | 29篇 |
2011年 | 39篇 |
2010年 | 27篇 |
2009年 | 35篇 |
2008年 | 31篇 |
2007年 | 34篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 23篇 |
1997年 | 27篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 16篇 |
1991年 | 18篇 |
1990年 | 23篇 |
1989年 | 13篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 18篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 32篇 |
1980年 | 19篇 |
1979年 | 13篇 |
1978年 | 30篇 |
1977年 | 30篇 |
1976年 | 38篇 |
1975年 | 25篇 |
1974年 | 20篇 |
1973年 | 21篇 |
1972年 | 17篇 |
1971年 | 22篇 |
1970年 | 23篇 |
1968年 | 16篇 |
排序方式: 共有1283条查询结果,搜索用时 0 毫秒
1.
Alexander Pavlov Gonzalo D Garcia De Fernando Juan A Ordoez Lorenzo Hoz 《Journal of the science of food and agriculture》1994,64(2):141-143
The β-hydroxyacyl-CoA-dehydrogenase (HADH) activity of unfrozen and thawed frog legs was investigated. The enzyme was extracted by either immersing frog legs in phosphate buffer 0.1 M, pH 6.0 at 25°C for 15 min or pressing them between trichinoscopy glasses. The enzyme activity was assayed using acetoacetyl-CoA as substrate and measured spectrophotometrically at 340 nm. It was possible by both extraction methods to distinguish between thawed and unfrozen samples although when the juice was obtained by pressing the HADH activity of the dilution was ~ 1.5 times higher than that obtained by immersion. The HADH activity was significantly higher (P≤0·001) in frozen-thawed frogs than in unfrozen legs because during freezing there is a release of HADH. No significative differences were found in the HADH activity in samples frozen in the temperature range -10 to -196°C. HADH activity was not affected by the storage time in crushed ice up to 6 days. 相似文献
2.
3.
4.
Kseniia A. Sergeeva Dmitrii V. Pavlov Albert A. Seredin Eugeny V. Mitsai Aleksandr A. Sergeev Evgeny B. Modin Anastasiia V. Sokolova Tsz Chun Lau Kseniia V. Baryshnikova Mihail I. Petrov Stephen V. Kershaw Aleksandr A. Kuchmizhak Kam Sing Wong Andrey L. Rogach 《Advanced functional materials》2023,33(44):2307660
In order to advance the development of quantum emitter-based devices, it is essential to enhance light-matter interactions through coupling between semiconductor quantum dots with high quality factor resonators. Here, efficient tuning of the emission properties of HgTe quantum dots in the infrared spectral region is demonstrated by coupling them to a plasmonic metasurface that supports bound states in the continuum. The plasmonic metasurface, composed of an array of gold nanobumps, is fabricated using single-step direct laser printing, opening up new opportunities for creating exclusive 3D plasmonic nanostructures and advanced photonic devices in the infrared region. A 12-fold enhancement of the photoluminescence in the 900–1700 nm range is observed under optimal coupling conditions. By tuning the geometry of the plasmonic arrays, controllable shaping of the emission spectra is achieved, selectively enhancing specific wavelength ranges across the emission spectrum. The observed enhancement and shaping of the emission are attributed to the Purcell effect, as corroborated by systematic measurements of radiative lifetimes and optical simulations based on the numerical solution of Maxwell's equations. Moreover, coupling of the HgTe photoluminescence to high quality factor modes of the metasurface improves emission directivity, concentrating output within an ≈20° angle. 相似文献
5.
Matveenko O. S. Gnatyuk D. L. Bugaev A. S. Pavlov A. Yu. Gamkrelidze S. A. Galiev R. R. Zuev A. V. Fedorov Yu. V. Lavrukhin D. V. Mikhalev A. O. Zenchenko N. K. 《Russian Microelectronics》2022,51(3):149-154
Russian Microelectronics - A set of monolithic integrated circuits (MICs) in the 22–25 GHz range based on gallium nitride nanoheterostructures on sapphire substrates is designed, produced,... 相似文献
6.
A. V. Ikonnikov K. V. Marem’yanin S. V. Morozov V. I. Gavrilenko A. Yu. Pavlov N. V. Shchavruk R. A. Khabibullin R. R. Reznik G. E. Cirlin A. E. Zhukov Zh. I. Alferov 《Technical Physics Letters》2017,43(4):362-365
I–V and radiative characteristics of multilayer quantum-cascade GaAs/AlGaAs heterostructures with a double metal waveguide are investigated. The I–V characteristics typical of the quantum-cascade lasers are seen. The observed threshold-intensity growth and narrow radiation spectrum are characteristic of laser generation. The measured radiation frequency was found to be about 3 THz, which coincides with the calculated value. Thus, fully domestic terahertz quantum-cascade lasers are demonstrated for the first time. 相似文献
7.
Desorption of cesium atoms from a rhenium point emitter in an electric field has been studied by method of field-desorption microscopy (FDM). Dependence of the desorbing field on degree of emitter surface coverage with Cs atoms is established. The heat of Cs-atom adsorption, which is dependent on the surface concentration of adsorbate and work function of the surface, is estimated in the framework of the model of mirror-image forces for field-induced desorption. Saturation of the rhenium emitter with carbon leads to changes in the character of desorption and in the distribution of desorption zones on the emitter surface.
相似文献8.
The goal of this work is to analyze various classes of finite and total monomial orderings. The concept of monomial ordering plays the key role in the theory of Gröbner bases: every basis is determined by a certain ordering. At the same time, in order to define a Gröbner basis, it is not necessary to know ordering of all monomials. Instead, it is sufficient to know only a finite interval of the given ordering. We consider combinatorics of finite monomial orderings and its relationship with cells of a universal Gröbner basis. For every considered class of orderings (weakly admissible, convex, and admissible), an algorithm for enumerating finite orderings is discussed and combinatorial integer sequences are obtained. An algorithm for computing all minimal finite orderings for an arbitrary Gröbner basis that completely determine this basis is presented. The paper presents also an algorithm for computing an extended universal Gröbner basis for an arbitrary zero-dimensional ideal. 相似文献
9.
10.
Aleksandra Ochneva Yana Zorkina Olga Abramova Olga Pavlova Valeriya Ushakova Anna Morozova Eugene Zubkov Konstantin Pavlov Olga Gurina Vladimir Chekhonin 《International journal of molecular sciences》2022,23(22)
Mental disorders represent common brain diseases characterized by substantial impairments of social and cognitive functions. The neurobiological causes and mechanisms of psychopathologies still have not been definitively determined. Various forms of brain proteinopathies, which include a disruption of protein conformations and the formation of protein aggregates in brain tissues, may be a possible cause behind the development of psychiatric disorders. Proteinopathies are known to be the main cause of neurodegeneration, but much less attention is given to the role of protein impairments in psychiatric disorders’ pathogenesis, such as depression and schizophrenia. For this reason, the aim of this review was to discuss the potential contribution of protein illnesses in the development of psychopathologies. The first part of the review describes the possible mechanisms of disruption to protein folding and aggregation in the cell: endoplasmic reticulum stress, dysfunction of chaperone proteins, altered mitochondrial function, and impaired autophagy processes. The second part of the review addresses the known proteins whose aggregation in brain tissue has been observed in psychiatric disorders (amyloid, tau protein, α-synuclein, DISC-1, disbindin-1, CRMP1, SNAP25, TRIOBP, NPAS3, GluA1, FABP, and ankyrin-G). 相似文献