全文获取类型
收费全文 | 191篇 |
免费 | 2篇 |
专业分类
化学 | 102篇 |
晶体学 | 3篇 |
力学 | 6篇 |
数学 | 21篇 |
物理学 | 61篇 |
出版年
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1966年 | 1篇 |
1896年 | 1篇 |
排序方式: 共有193条查询结果,搜索用时 31 毫秒
31.
Alexey P. Ilyin Julia N. Peregudova Elena B. Poutsykina Dmitri V. Kravchenko 《Tetrahedron letters》2006,47(15):2649-2653
We present a convenient synthesis of heterocyclic scaffolds using a novel modification of four-component Ugi condensation. Two complementary variants of this useful synthetic strategy provide an efficient one-step assembly of four novel pharmaceutically relevant (hetero)aryl-fused 1,4-oxazepines with different substituents’ profile. 相似文献
32.
S. O. Ilyin V. V. Makarova T. S. Anokhina A. V. Volkov S. V. Antonov 《Polymer Science Series A》2017,59(5):676-684
Low-viscous coagulating agents are tradionally used to precipitate polymers from their solutions and obtain films and fibers from them; they represent, as a rule, the combinations of solvent and nonsolvent of the polymer used. At the same time, since the structure of the precipitated polymer is formed under non-equilibrium conditions, the influence of the coagulant viscosity can be quite substantial. The influence of the viscosity of the medium on the formation of structure, morphology, and transport characteristics of the precipitated polymer is studied by example of forming of the cellulose membranes from solution in N-methyl-morpholine N-oxide using some proton-donor coagulants. In this regard, the interdiffusion processes proceeding at the contact of cellulose solutions and coagulating agents (water, propylene glycol, glycerin) are explored using the laser interferometry method. Varying the precipitator viscosity allows one to change the rate of formation and correspondingly the morphology of the cellulose films. In turn, the membrane structure determines its transport characteristics, which were assessed by the filtration of aprotic media with anionic dyes—Orange II and Remazol Brilliant Blue R. The application of the low-viscous precipitator provides the formation of a uniform film structure in the bulk, but leads to development of defects close to the surface, while a viscous medium promotes the formation of a relatively thin dense shell on the films. 相似文献
33.
S. O. Ilyin V. V. Makarova M. P. Arinina E. G. Litvinova V. S. Khotimskii V. G. Kulichikhin 《Polymer Science Series A》2017,59(1):1-11
The phase equilibrium and rheological properties of poly(1-trimethylsilyl-1-propyne) solutions obtained with tantalum catalysts are studied. For three polymers with different molecular masses, phase diagrams are determined in a number of solvents. From these diagrams, the Hansen solubility parameters of poly(1-trimethylsilyl-1-propyne) are calculated by the method proposed in this work. Dilute solutions of poly(1-trimethylsilyl-1-propyne) behave as Newtonian liquids, whereas the viscosity of viscoelastic concentrated systems decreases as the shear rate grows. The molecular and rheological characteristics of studied poly(1-trimethylsilyl-1-propyne) samples are compared with the samples prepared with NbCl5 catalysts. Poly(1-trimethylsilyl-1-propyne) obtained with a catalytic system involving tantalum pentachloride is characterized by high intrinsic viscosity and solution viscosity compared to poly(1-trimethylsilyl-1-propyne) prepared with niobium catalyst. The difference in properties is due to the dissimilar ratios of cis and trans units in the samples. 相似文献
34.
S. O. Ilyin V. M. Spiridonova V. S. Savelyeva M. M. Ovchinnikov S. D. Khizhnyak E. I. Frenkin P. M. Pakhomov A. Ya. Malkin 《Colloid Journal》2011,73(5):646-650
Gelation in dilute aqueous L-cysteine solutions containing various electrolytes is studied by rotational viscometry in different
dynamic regimes. It is revealed that gels are formed at rather low concentrations of cysteine of no higher than 0.1 vol %.
In the linear range of mechanical actions, gels of all examined compositions behave as elastic solid-like media; their elastic
moduli, which lie in a range of 10–100 Pa, are independent of frequency and their mechanical losses are low. However, these
gels exhibit dualistic properties and can flow at low shear stresses with a Newtonian viscosity on the order of 103–105 Pa s. On reaching a critical stress (yield point), gels are destroyed, their viscosity decreases by six to seven decimal
orders of magnitude, and they are transformed into low-viscosity liquids. At rest, the initial structure and properties are
recovered. Mechanisms of percolation network formation are proposed. 相似文献
35.
In this paper we develop and use successive averaging methods for explaining the regularization mechanism in the the periodic Korteweg–de Vries (KdV) equation in the homogeneous Sobolev spaces Ḣs for s ≥ 0. Specifically, we prove the global existence, uniqueness, and Lipschitz‐continuous dependence on the initial data of the solutions of the periodic KdV. For the case where the initial data is in L2 we also show the Lipschitz‐continuous dependence of these solutions with respect to the initial data as maps from Ḣs to Ḣs for s ∈(−1,0]. © 2010 Wiley Periodicals, Inc. 相似文献
36.
Victor A. Soltamov Ivan V. Ilyin Alexandra A. Soltamova Daniel O. Tolmachev Nikolai G. Romanov Alexandr S. Gurin Vladimir A. Khramtsov Eugene N. Mokhov Yurii N. Makarov Georgy V. Mamin Sergei B. Orlinskii Pavel G. Baranov 《Applied magnetic resonance》2013,44(10):1139-1165
The results of studies of shallow donors and deep-level color centers in bulk AlN crystals are presented. Two shallow donors (presumably oxygen located on the nitrogen site and carbon located on the aluminum site) are suggested to exhibit the DX-relaxation. Third shallow donor (presumably silicon on the Al site) shows the shallow donor behavior up to the room temperature and can be observed without light excitation at temperatures above 200 K. The values of the Bohr radius of the shallow donors are estimated. The structure of deep-level color centers (neutral nitrogen vacancy V N) in bulk AlN crystals is determined and analyzed by electron paramagnetic resonance, electron-nuclear double resonance, optical absorption and thermoluminescence induced by X-ray irradiation. Spin-dependent recombination processes in AlN crystals are studied by means of optically detected magnetic resonance. 相似文献
37.
Abdullin S. Banerjee S. Bellucci L. Charlot C. Denegri D. Dittmar M. Drollinger V. Dubinin M.N. Dzelalija M. Green D. Iasvili I. Ilyin V.A. Kinnunen R. Kunori S. Lassila-Perini K. Lehti S. Mazumdar K. Moortgat F. Muller Th. Nikitenko A. Puljak I. Salmi P. Seez C. Slabospitsky S. Stepanov N. Vidal R. Wu W. Yildiz H.D. Zeyrek M. 《The European Physical Journal C - Particles and Fields》2005,39(2):41-61
The European Physical Journal C - This work summarizes the studies for the Higgs boson searches in CMS at the LHC collider. The main discovery channels are presented and the potential is given for... 相似文献
38.
E. N. Yurchenko V. Yu. Prokofev A. P. Ilyin Yu. G. Shyrokov 《Reaction Kinetics and Catalysis Letters》1997,60(2):269-277
Structure-mechanical and rheological characteristics of pastes on the basis of TiO2 and Al2O3 are discussed. Optinum values to prepare honeycomb supports are determined. 相似文献
39.
MM. P. Duballet A. Godard G. Queguiner P. Pastour 《Journal of heterocyclic chemistry》1973,10(6):1079-1080
This article describes the synthesis of a new heterocycle, pyrido[2,3,f]phtalazine and three new diformylquinolincs. 相似文献
40.
A hexafluorophosphate-selective electrode based on the tetradecylphosphonium hexafluorophosphate(V) ion-pair complex in a PVC membrane is described. The active material is a white powder; its solution in dibutyl phthalate was used for the electrode membranes. The composition of the tetradecylphosphonium hexafluorophosphate was identified as its infrared and 31P-n.m.r. spectra. The calibration curves for the elelctrode were investigated and interpreted with respect to the hydrogen fluoride concentration of the sample solution. It is shown that the hydrolysis of hexafluorophosphate depends on the hydrofluoric acid content of the solution. The lifetime of the electrodes is about one month and the limits of detection vary from aobut 10?7 mol 1?1 to 10?6 mol 1?1 with 0–1 mol 1?1 hydrofluoric acid present. 相似文献