全文获取类型
收费全文 | 1024篇 |
免费 | 31篇 |
国内免费 | 6篇 |
专业分类
化学 | 780篇 |
晶体学 | 17篇 |
力学 | 18篇 |
数学 | 32篇 |
物理学 | 214篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 23篇 |
2021年 | 29篇 |
2020年 | 21篇 |
2019年 | 22篇 |
2018年 | 9篇 |
2017年 | 23篇 |
2016年 | 17篇 |
2015年 | 26篇 |
2014年 | 28篇 |
2013年 | 55篇 |
2012年 | 82篇 |
2011年 | 77篇 |
2010年 | 39篇 |
2009年 | 41篇 |
2008年 | 64篇 |
2007年 | 66篇 |
2006年 | 80篇 |
2005年 | 72篇 |
2004年 | 53篇 |
2003年 | 61篇 |
2002年 | 42篇 |
2001年 | 26篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有1061条查询结果,搜索用时 0 毫秒
101.
Jung Bin In Bin Xiang David J. Hwang Sang-Gil Ryu Eunpa Kim Jae-Hyuck Yoo Oscar Dubon Andrew M. Minor Costas P. Grigoropoulos 《Applied Physics A: Materials Science & Processing》2014,114(1):277-285
We observe laser-induced grain morphology change in silicon nanopillars under a transmission electron microscopy (TEM) environment. We couple the TEM with a near-field scanning optical microscopy pulsed laser processing system. This novel combination enables immediate scrutiny on the grain morphologies that the pulsed laser irradiation produces. We find unusual transformation of the tip of the amorphous or polycrystalline silicon pillar into a single crystalline domain via melt-mediated crystallization. On the basis of the three-dimensional finite difference simulation result and the dark field TEM data, we propose that the creation of the distinct single crystalline tip originates from the dominant grain growth initiated at the apex of the non-planar liquid–solid interface. Our microscopic observation provides a fundamental basis for laser-induced conversion of amorphous nanostructures into coarse-grained crystals. 相似文献
102.
Ryu Sasaki 《Czechoslovak Journal of Physics》2003,53(11):1111-1117
The relationship (resemblance and/or contrast) between quantum and classical integrability in Ruijsenaars-Schneider (R-S) and Calogero-Moser systems is addressed. The classical Calogero and Sutherland systems (based on any root system) at equilibrium have many remarkable properties; for example, the minimum energies, frequencies of small oscillations and the eigenvalues of Lax pair matrices at equilibrium are all integer valued. These are related to the energy eigenvalues of the quantum Calogero and Sutherland systems. Similar features and results hold for the R-S type of integrable systems based on the classical root systems. 相似文献
103.
Koike R Motoyoshiya J Takaguchi Y Aoyama H 《Chemical communications (Cambridge, England)》2003,(6):794-795
A kinetic study of peroxyoxalate chemiluminescence reactions employing 2,4,6-trichlorophenyl N-aryl-N-tosyloxamates supports the 1,2-dioxetanones still bearing the eliminating group as the key intermediates that interact with the fluorophores rather than 1,2-dioxetanedione. 相似文献
104.
Kyukwan Zong Seung Il Shin Dong Ju Jeon Jung No Lee Eung K. Ryu 《Journal of heterocyclic chemistry》2000,37(1):75-78
3‐Aryl‐4‐methoxycarbonylisoxazoles were prepared from the reaction of a variety of substituted benzonitrile oxides with methyl 3‐(p‐nitrobenzoyloxy)acrylate in moderate to good yields. 相似文献
105.
Jang HS Ryu KE Ahn WS Chun HJ Dal Park H Park KD Kim YH 《Colloids and surfaces. B, Biointerfaces》2006,50(2):141-146
Previously, novel poly(ethylene glycol) (PEG) and sulfonated PEG acrylate (PEG-SO3A/OA) copolymers were prepared as coating and/or blending materials for biomedical applications. Surfaces modified with copolymers exhibited increased anti-coagulation properties and decreased plasma adsorption level due to increased hydrophilic properties and reorientation characteristics of PEG/PEG-SO3A chains in water phase. As continuation study, anti-complement effects of PEG-SO3/OA copolymers were investigated in vitro, and compared with those of low-density polyethylene (LDPE) and PEG/OA. C3 activation by PEG-SO3/OA samples was lower than that by PEG/OA samples, which was attributed to decreased surface nucleophile level of samples. PEG-SO3/OA samples increased inhibition of Bb production, resulting in decreased C5 activation. Owing to reduced activations of C3 and C5, PEG-SO3/OA samples markedly decreased SC5b-9 levels in plasma. 相似文献
106.
Dr. Todor Baramov Bianca Schmid Ho Ryu Jinhoon Jeong Dr. Karlijn Keijzer Dr. Leonard von Eckardstein Prof. Dr. Mu-Hyun Baik Prof. Dr. Roderich D. Süssmuth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(28):6955-6962
The E. coli siderophore enterobactin, the strongest FeIII chelator known to date, forms hexacoordinate complexes with SiIV, GeIV, and TiIV. Synthetic protocols have been developed to prepare non-symmetric enterobactin analogues with varying denticities. Various benzoic acid residues were coupled to the macrocyclic lactone to afford a diverse library of ligands. These enterobactin analogues were bound to SiIV, GeIV, and TiIV, and the complexes were investigated through experimental and computational techniques. The binding behavior of the synthesized chelators enabled assessment of the contribution of each of the phenolic hydroxy groups in enterobactin to metal-ion complexation. It was found that at least four O-donors are needed for enterobactin derivatives to act as metal binders. Density functional theory calculations indicate that the strong binding behavior of enterobactin can be ascribed to a diminished translational entropy penalty, a common feature of the chelate effect, coupled with the structural arrangement of the three catechol moieties, which allows the triseryl base to be installed without distorting the preferred local metal-binding geometry of the catecholate ligands. 相似文献
107.
Kim MG Shin BS Choi Y Ryu JK Shin SW Choo HW Yoo SD 《Biomedical chromatography : BMC》2012,26(5):660-665
This study describes the development of a rapid and sensitive high‐performance liquid chromatography–electrospray ionization tandem mass spectrometry (LC‐MS/MS) assay for the quantification of [6]‐gingerol in mouse plasma and application to a pharmacokinetic study after dose ranging in mice. The assay involved a protein precipitation step with acetonitrile and an isocratic elution using a mobile phase consisting of acetonitrile and water containing 0.1% formic acid (80:20 v/v). The multiple reaction monitoring was based on the transition of m/z = 277.2 → 177.1 for [6]‐gingerol and 294.2 → 137.1 for nonivamide (internal standard). The assay was validated to demonstrate the specificity, linearity, recovery, accuracy, precision and stability. The calibration curves were linear over the wide concentration range of 10–10,000 ng/mL (r ≥ 0.9988). The lower limit of quantification was 10 ng/mL using a small volume of mouse plasma (20 μL). The method was successfully applied to a pharmacokinetic study in mice after intravenous injection of [6]‐gingerol at 1.5, 3 and 6 mg/kg doses. The pharmacokinetics of [6]‐gingerol were linear over the dose range studied as demonstrated by the linear increase in area under the concentration‐time curve (AUCinf) with no significant change in the systemic clearance (Cls), volume of distribution (Vss) and elimination half‐life (t1/2) as a function of dose. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
108.
Masayuki Kirihara Takuya Noguchi Nobuhiro Okajima Sayuri Naito Yuki Ishizuka Aiko Harano Hiroyuki Tsukiji Ryu Takizawa 《Tetrahedron》2012,68(5):1515-1520
The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of tantalum(V) and iodide ion effectively produced carbonyl compounds in high yields. Dithioacetals also can be deprotected using the niobium(V) catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions. 相似文献
109.
Metal ion affinity purification of proteins by genetically incorporating metal-chelating amino acids
Affinity tags are efficient tools for protein purification. They allow simple one-step purification of proteins to high purity. However, in some cases the tags cause structural and functional changes in a protein, and need to be removed. Therefore, affinity tags that are readily introduced into proteins with minimal perturbation and have specific affinity for purification are desired. Herein, two metal-chelating amino acids derived from 2,2′-bipyridine and 8-hydroxyquinoline were genetically incorporated into glutathione S-transferase (GST) and the mutant proteins were purified by using the metal ion affinity of the unnatural amino acids. The purification of the GST mutants containing 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA) showed that the proteins could be efficiently enriched in Ni–NTA by the metal ion affinity of the unnatural amino acid and purified to excellent purity. This method should be very useful for general protein affinity purification, especially for proteins whose structure or function is affected by affinity tags fused to N- or C-terminals. 相似文献
110.
Won Jung Yoon Jae Hoon Ryu Cheolhoon Cheong Kyu Yong Choi 《Macromolecular theory and simulations》1998,7(3):327-332
Molecular weight averages have long been used as a measure of polymer molecular weight properties in industrial polymer manufacturing processes. With a kinetic model, it is possible to directly calculate the polymer chain length distribution by integrating an infinite number of the polymer population balance equations. However, when the polymer chain length is very large, such a direct integration of polymer population balance equations can be computationally demanding. In this paper, the method of finite molecular weight moments is applied to the calculation of polymer chain length distribution in a batch free radical thermal polymerization of styrene. The weight fraction of a finite chain length interval is directly calculated in conjunction with a kinetic model. The method of calculation is illustrated through model simulations. 相似文献