全文获取类型
收费全文 | 10396篇 |
免费 | 472篇 |
国内免费 | 53篇 |
专业分类
化学 | 8261篇 |
晶体学 | 98篇 |
力学 | 168篇 |
数学 | 1101篇 |
物理学 | 1293篇 |
出版年
2024年 | 8篇 |
2023年 | 103篇 |
2022年 | 271篇 |
2021年 | 504篇 |
2020年 | 298篇 |
2019年 | 313篇 |
2018年 | 256篇 |
2017年 | 212篇 |
2016年 | 416篇 |
2015年 | 334篇 |
2014年 | 440篇 |
2013年 | 670篇 |
2012年 | 754篇 |
2011年 | 858篇 |
2010年 | 537篇 |
2009年 | 444篇 |
2008年 | 680篇 |
2007年 | 619篇 |
2006年 | 583篇 |
2005年 | 474篇 |
2004年 | 388篇 |
2003年 | 291篇 |
2002年 | 270篇 |
2001年 | 137篇 |
2000年 | 114篇 |
1999年 | 74篇 |
1998年 | 77篇 |
1997年 | 58篇 |
1996年 | 70篇 |
1995年 | 54篇 |
1994年 | 48篇 |
1993年 | 49篇 |
1992年 | 40篇 |
1991年 | 45篇 |
1990年 | 37篇 |
1989年 | 36篇 |
1988年 | 26篇 |
1987年 | 25篇 |
1986年 | 30篇 |
1985年 | 45篇 |
1984年 | 24篇 |
1983年 | 17篇 |
1982年 | 30篇 |
1981年 | 21篇 |
1980年 | 22篇 |
1979年 | 12篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1932年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
Background
General iron-sulfur cluster biosynthesis proceeds through assembly of a transient cluster on IscU followed by its transfer to a recipient apo-protein. The efficiency of the second step is increased by the presence of HscA and HscB, but the reason behind this is poorly understood. To shed light on the function of HscB, we began a study on the nature of its interaction with IscU. Our work suggested that the binding site of IscU is in the C-terminal domain of HscB, and two different triple alanine substitutions ([L92A, M93A, F153A] and [E97A, E100A, E104A]) involving predicted binding site residues had detrimental effects on this interaction. However, the individual contribution of each substitution to the observed effect remains to be determined as well as the possible involvement of other residues in the proposed binding site. 相似文献993.
Emil Byström Anna Nordborg Fredrik Limé Ngoc Phuoc Dinh Knut Irgum 《Journal of separation science》2010,33(11):1563-1570
A combined surface activation and “grafting to” strategy was developed to convert divinylbenzene particles into weak cation exchangers suitable for protein separation. The initial activation step was based on plasma modification with bromoform, which rendered the particles amenable to further reaction with nucleophiles by introducing Br to a surface content of 11.2 atom‐%, as determined by X‐ray photoelectron spectroscopy. Grafting of thiol‐terminated glydicyl methacrylate telomers to freshly plasma activated surfaces was accomplished without the use of added initiator, and the grafting was verified both by reduction in bromine content and the appearance of sulfur‐carbon linkages, showing that the surface grafts were covalently bonded. Following grafting the attached glydicyl methacrylate telomer tentacles were further modified by a two‐step procedure involving hydrolysis to 2,3‐hydroxypropyl groups and conversion of hydroxyl groups to carboxylate functionality by succinic anhydride. The final material was capable of baseline separating four model proteins in 3 min by gradient cation exchange chromatography in a fully aqueous eluent. 相似文献
994.
995.
Anna S. Gardberg Brian S. Potter Rex A. Palmer Garry J. McIntyre Dean A. A. Myles 《Journal of chemical crystallography》2011,41(4):470-480
Abstract
Single-crystal neutron diffraction data were collected at 20 K to a resolution of 1.05 ? on a crystal of the inverse formyl peptide receptor agonist cyclosporin H, CsH, (crystal form II, CsH-II) on the Laue diffractometer VIVALDI at the Institut Laue-Langevin (Grenoble). The solvent structure and hydrogen bonding network of CsH-II have been unambiguously determined by single-crystal neutron diffraction; the agreement factor R(F 2) is 13.5% for all 2726 reflections. All hydrogen atom positions, including methyl-group orientations, have been determined by crystallographic refinement. The neutron structure of cyclosporin provides unique and complementary insights into methyl orientation, hydrogen-bonding, and solvent interactions that are not available from X-ray analysis alone. 相似文献996.
It was proved in [1] that every planar graph with girth g ≥ 6 and maximum degree Δ ≥ 8821 is 2-distance (Δ + 2)-colorable. We prove that every planar graph with g ≥ 6 and Δ ≥ 24 is list 2-distance (Δ + 2)-colorable. 相似文献
997.
María P. Utrillas María J. Marín Anna R. Esteve Victor Estellés Fernando Tena Javier Cañada José A. Martínez-Lozano 《Photochemistry and photobiology》2009,85(5):1245-1253
Values of measured and modeled diffuse UV erythemal irradiance (UVER) for all sky conditions are compared on planes inclined at 40° and oriented north, south, east and west. The models used for simulating diffuse UVER are of the geometric-type, mainly the Isotropic, Klucher, Hay, Muneer, Reindl and Schauberger models. To analyze the precision of the models, some statistical estimators were used such as root mean square deviation, mean absolute deviation and mean bias deviation. It was seen that all the analyzed models reproduce adequately the diffuse UVER on the south-facing plane, with greater discrepancies for the other inclined planes. When the models are applied to cloud-free conditions, the errors obtained are higher because the anisotropy of the sky dome acquires more importance and the models do not provide the estimation of diffuse UVER accurately. 相似文献
998.
999.
We investigate quantum correlations in the ground state of the Moshinsky model formed by N harmonically interacting particles confined in a harmonic potential. The model is solvable which allows an exact determination of entanglement between the subset of p particles and the remaining N ? p particles. We study linear entropies and von Neumann entropies of the bipartitions and compare their behavior with that of the relative correlation energy and of the statistical Kutzelnigg coefficient. 相似文献
1000.