全文获取类型
| 收费全文 | 198篇 |
| 免费 | 8篇 |
| 国内免费 | 3篇 |
专业分类
| 化学 | 108篇 |
| 晶体学 | 1篇 |
| 力学 | 17篇 |
| 数学 | 37篇 |
| 物理学 | 46篇 |
出版年
| 2024年 | 2篇 |
| 2023年 | 3篇 |
| 2022年 | 7篇 |
| 2021年 | 13篇 |
| 2020年 | 5篇 |
| 2019年 | 12篇 |
| 2018年 | 5篇 |
| 2017年 | 1篇 |
| 2016年 | 6篇 |
| 2015年 | 3篇 |
| 2014年 | 13篇 |
| 2013年 | 21篇 |
| 2012年 | 10篇 |
| 2011年 | 17篇 |
| 2010年 | 9篇 |
| 2009年 | 8篇 |
| 2008年 | 14篇 |
| 2007年 | 12篇 |
| 2006年 | 11篇 |
| 2005年 | 7篇 |
| 2004年 | 8篇 |
| 2003年 | 4篇 |
| 2002年 | 1篇 |
| 2000年 | 1篇 |
| 1998年 | 1篇 |
| 1997年 | 1篇 |
| 1996年 | 1篇 |
| 1995年 | 2篇 |
| 1994年 | 2篇 |
| 1993年 | 2篇 |
| 1990年 | 2篇 |
| 1984年 | 2篇 |
| 1983年 | 2篇 |
| 1981年 | 1篇 |
排序方式： 共有209条查询结果，搜索用时 15 毫秒
31.
32.
Santiago F. Yunes Jos C. Gesser Hernan Chaimovich Faruk Nome 《Journal of Physical Organic Chemistry》1997,10(6):461-465
The hydrolysis of the 2′,2′,2′-trifluoroethyl monoester of 1,8-naphthalic acid ( 1 ) proceeds via the monoanion with the intermediate formation of the corresponding anhydride. The rate constant for the formation of 1,8-naphthalic anhydride ( 2 ) is ca 2500 times faster than its rate of hydrolysis. The isotope effect in the plateau region and theoretical calculations at the PM3 level suggest that elimination of the alkoxide is the rate-limiting step for the reaction. Accordingly, decomposition of the isopropyl monoester of naphthalic acid proceeds 104 times slower than the spontaneous decomposition of 1 . The remarkably high rate of monoester decomposition derives from the special configuration of the substrates and important contributions that arise from relief of torsional strain, which clearly includes electron redistribution due to the decrease in steric hindrance to resonance and the fact that proximity obviates solvation. © 1997 John Wiley & Sons, Ltd. 相似文献
33.
In this paper we study the critical behaviors of the half‐integer mixed spin‐3/2 and spin‐5/2 Blume–Capel Ising ferrimagnetic system by using the exact recursion relations on the Bethe lattice for q = 4 and 6, whose real lattice correspondences are square and simple cubic lattices, respectively. We have obtained the phase diagrams in the (kTc/|J |, DA /|J |) planes for constant values of DB /|J |, the reduced crystal field of the sublattice with spin‐5/2, and in the (kTc/|J |, DB /|J |) planes for constant values of DA /|J |, the reduced crystal field of the sublattice with spin‐3/2. Even if the system presents both second‐ and first‐order phase transitions, their lines never connect to each other and end at critical points; thus, no tricritical points are observed. We have also found the existence of one or two compensation temperatures for appropriate values of the crystal fields, therefore observing reentrant behavior for some of the compensation lines. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
34.
Canan Çelik;Faruk Develi; 《Mathematical Methods in the Applied Sciences》2024,47(6):5090-5097
This paper focuses on revisiting and improving the results regarding the existence of a solution to the implicit fractional differential equations (FDEs) given in the following form: 相似文献
35.
Doaa H. M. Alsaadi Aedla Raju Ken Kusakari Faruk Karahan Nazim Sekeroglu Takashi Watanabe 《Molecules (Basel, Switzerland)》2020,25(23)
The growth and quality of licorice depend on various environmental factors, including the local climate and soil properties; therefore, its cultivation is often unsuccessful. The current study investigated the key factors that affect the contents of bioactive compounds of Glycyrrhiza glabra L. root and estimated suitable growth zones from collection sites in the Hatay region of Turkey. The contents of three bioactive compounds (glycyrrhizic acid, glabridin, and liquiritin), soil factors (pH, soil bearing capacity, and moisture content), and geographical information (slope, aspect, curvature, elevation, and hillshade) were measured. Meteorological data (temperature and precipitation) were also obtained. An analysis of variance (ANOVA) and multivariate analysis of variance (MANOVA) were performed on the data. The soil bearing capacity, moisture content, slope, aspect, curvature, and elevation of the study area showed statistically significant effects on the glycyrrhizic acid and liquiritin contents. A habitat suitability zone map was generated using a GIS-based frequency ratio (FR) model with spatial correlations to the soil, topographical, and meteorological data. The final map categorized the study area into four zones: very high (15.14%), high (31.50%), moderate (40.25%), and low suitability (13.11%). High suitability zones are recommended for further investigation and future cultivation of G. glabra. 相似文献
36.
Transport in Porous Media - Stress dependency of permeability of porous rocks is described by means of a theoretical elastic cylindrical pore-shell model. This model is developed based on a bundle... 相似文献
37.
Faruk Civan 《Numerical Methods for Partial Differential Equations》2009,25(2):347-379
Methodology for development of compact numerical schemes by the practical finite‐analytic method (PFAM) is presented for spatial and/or temporal solution of differential equations. The advantage and accuracy of this approach over the conventional numerical methods are demonstrated. In contrast to the tedious discretization schemes resulting from the original finite‐analytic solution methods, such as based on the separation of variables and Laplace transformation, the practical finite‐analytical method is proven to yield simple and convenient discretization schemes. This is accomplished by a special universal determinant construction procedure using the general multi‐variate power series solutions obtained directly from differential equations. This method allows for direct incorporation of the boundary conditions into the numerical discretization scheme in a consistent manner without requiring the use of artificial fixing methods and fictitious points, and yields effective numerical schemes which are operationally similar to the finite‐difference schemes. Consequently, the methods developed for numerical solution of the algebraic equations resulting from the finite‐difference schemes can be readily facilitated. Several applications are presented demonstrating the effect of the computational molecule, grid spacing, and boundary condition treatment on the numerical accuracy. The quality of the numerical solutions generated by the PFAM is shown to approach to the exact analytical solution at optimum grid spacing. It is concluded that the PFAM offers great potential for development of robust numerical schemes. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009 相似文献
38.
Avdic Senada Demirovic Damir Hadzimustafic Edin Cickusic Zerina Sehic Faruk 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(6):2645-2654
Journal of Radioanalytical and Nuclear Chemistry - Responses of the hand-held gamma monitors available for the ambient dose equivalent rate measurements in the Federation of Bosnia and Herzegovina... 相似文献
39.
Fevzihan Basarir Farid Sayar Irani Arif Kosemen B. Tugba Camic Faruk Oytun Bahadir Tunaboylu Hee Jeong Shin Ki Young Nam Hyosung Choi 《Materials Today Chemistry》2017
Organic photovoltaics (OPVs) are considered as a future alternative for conventional silicon based solar cells, owing to their low cost, ease of production and high-throughput. The transparent conducting electrode (TCE) is a fundamental component of OPVs. Traditionally, indium tin oxide (ITO) has been mainly utilized as a TCE in OPV applications due to its relatively high transparency and low sheet resistance. However, increasing demand for the optoelectronic devices has led to large fluctuations in ITO prices in the past decade and ITO is known to account more than 50% of the total cost of OPV devices. Thus, it is believed that development of solution-processable alternative materials is of great importance in reducing the cost of OPVs. Numerous materials, including silver nanowires, carbon nanotubes, graphene and conducting polymers, have been offered as replacements for ITO. This article reviews recent progress on fabrication of TCE via solution based coating techniques of silver nanowires (Ag NWs). In addition, performance of the Ag NWs based TCE in OPVs is summarized. Finally, we explore the future outlook for Ag NWs based TCE at the end of the review. 相似文献
40.
The effects of assuming equal or unequal crystal fields (CF) on the phase diagrams of a mixed spin-1 and spin-5/2 system are investigated in terms of the recursion relations on the Bethe lattice (BL). The equal CF case was considered for the coordination numbers q=3, 4, and 6, while for q=3 the unequal CF case was also studied. It was found that for the equal CF case, the model exhibits second-order phase transitions and two compensation temperatures for all q, the reentrant behavior for q=4 and first-order phase transitions and tricritical point (TCP) for q=6. In the unequal CF case for q=3, the system yields first- and second-order phase transitions, TCP's, and three compensation temperatures. In addition, the TCP's in a very short range are classified as the stable and unstable ones depending on their free energies. 相似文献