全文获取类型
收费全文 | 341篇 |
免费 | 13篇 |
国内免费 | 4篇 |
专业分类
化学 | 221篇 |
晶体学 | 2篇 |
力学 | 11篇 |
综合类 | 3篇 |
数学 | 61篇 |
物理学 | 60篇 |
出版年
2023年 | 6篇 |
2022年 | 17篇 |
2021年 | 19篇 |
2020年 | 17篇 |
2019年 | 22篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 10篇 |
2015年 | 15篇 |
2014年 | 14篇 |
2013年 | 34篇 |
2012年 | 18篇 |
2011年 | 20篇 |
2010年 | 16篇 |
2009年 | 14篇 |
2008年 | 17篇 |
2007年 | 11篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有358条查询结果,搜索用时 218 毫秒
31.
32.
33.
Hopf Bifurcation and Stability of Periodic Solutions of Differential-difference and Integro-differential Equations 总被引:6,自引:0,他引:6
KAZARINOFF N. D.; WAN Y.-H; VAN DEN DRIESSCHE P. 《IMA Journal of Applied Mathematics》1978,21(4):461-477
Periodic solutions bifurcating from a steady state of differential-differenceand integrodifferential equations are studied. An algorithmfor determining the asymptotic orbital stability, directionof bifurcation, period, and asymptotic form of these solutionsis presented. This algorithm is applied to the Hutchinson-Wrightequation and to an equation with two delays. Finally some integro-differentialequations, modelling two and three trophic level competition,introduced by May, are discussed. Some numerical work supportingthe theory is described. 相似文献
34.
Avcı Davut Altürk Sümeyye Sönmez Fatih Tamer Ömer Başoğlu Adil Atalay Yusuf Zengin Kurt Belma Dege Necmi 《Molecular diversity》2021,25(1):171-189
Molecular Diversity - The World Health Organization (WHO) report shows that diabetes mellitus (DM) will be one of the ten deadly diseases in the near future. The best way to prevent DM is to... 相似文献
35.
Phytochemical investigation of the ethyl acetate extract of the leaves of Juniperus procera growing in south Saudi Arabia Enemas region led to the isolation of a new flavonoid using different chromatographic methods (i.e. paper, thin layer and column chromatography). The isolated flavonoid was identified and established by m.p., 1H-NMR, 13C-NMR, UV and MS spectral analysis. The isolated compound was identified as 3′,4′,3,7-tetrahydroxyflavone. 相似文献
36.
Adil Belhaj 《Physics letters. [Part B]》2011,705(5):539-542
Using D-brane physics, we study fractional quantum Hall solitons (FQHS) in ABJM-like theory in terms of type IIA dual geometries. In particular, we discuss a class of Chern-Simons (CS) quivers describing FQHS systems at low energy. These CS quivers come from R-R gauge fields interacting with D6-branes wrapped on 4-cycles, which reside within a blown up CP3 projective space. Based on the CS quiver method and mimicking the construction of del Pezzo surfaces in terms of CP2, we first give a model which corresponds to a single layer model of FQHS system, then we propose a multi-layer system generalizing the doubled CS field theory, which is used in the study of topological defect in graphene. 相似文献
37.
Ndubuisi B. Ukah Satyaprasad P. Senanayak Danish Adil Grant Knotts Jimmy Granstrom K. S. Narayan Suchi Guha 《Journal of Polymer Science.Polymer Physics》2013,51(21):1533-1542
Low‐operating voltage, high mobility, and stable organic field‐effect transistors (OFETs) using polymeric dielectrics such as pristine poly(4‐vinyl phenol) (PVP) and poly(methyl methacrylate) (PMMA), dissolved in solvents of high dipole moment, have been achieved. High dipole moment solvents such as propylene carbonate and dimethyl sulfoxide used for dissolving the polymer dielectric enhance the charge carrier mobilities by three orders of magnitude in pentacene OFETs compared with low dipole moment solvents. Fast switching circuits with patterned gate PVP‐based pentacene OFETs demonstrated a switching frequency of 75 kHz at input voltages of |5 V|. The frequency response of the OFETs is attributed to a high degree of dipolar‐order in dielectric films obtained from high‐polarity solvents and the resulting energetically ordered landscape for transport. Remarkably, these pentacene‐based OFETs exhibited high stability under bias stress and in air with negligible shifts in the threshold voltage. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1533–1542 相似文献
38.
Adil Yaqub 《Results in Mathematics》2006,49(3-4):377-386
A well-known theorm of Jacobson asserts that a ring R with the property that for every x in R there exists an integer n(x) > 1 such that xn(x) = x is necessarily commutative. With this as motivation, we define an N0-ring to be a ring which satisfies a weaker hypothesis than the “xn(x) = x” condition in Jacobson’s Theorem. We consider commutativity of N0-rings, usually with the additional hypothesis that the ground ring is also weakly periodic-like. 相似文献
39.
40.
Dilara Saçlıgil Serap Şenel Handan Yavuz Adil Denizli 《Journal of separation science》2015,38(15):2729-2736
Immunoaffinity adsorbent for transferrin (Tf) purification was prepared by immobilizing anti‐transferrin (Anti‐Tf) antibody on magnetic monosizepoly(glycidyl methacrylate) beads, which were synthesized by dispersion polymerization technique in the presence of Fe3O4nanopowder and obtained with an average size of 2.0 μm. The magnetic poly(glycidyl methacrylate) (mPGMA) beads were characterized by Fourier transform infrared spectroscopy, swelling tests, scanning electron microscopy, electron spin resonance spectroscopy, thermogravimetric analysis and zeta sizing analysis. The density and swelling ratio of the beads were 1.08 g/cm3 and 52%, respectively. Anti‐Tf molecules were covalently coupled through epoxy groups of mPGMA. Optimum binding of anti‐Tf was 2.0 mg/g. Optimum Tf binding from aqueous Tf solutions was determined as 1.65 mg/g at pH 6.0 and initial Tf concentration of 1.0 mg/mL. There was no remarkable loss in the Tf adsorption capacity of immunoaffinity beads after five adsorption–desorption cycles. Tf adsorption from artificial plasma was also investigated and the purity of the Tf molecules was shown with gel electrophoresis studies. 相似文献