全文获取类型
收费全文 | 289篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
化学 | 160篇 |
晶体学 | 10篇 |
力学 | 16篇 |
数学 | 60篇 |
物理学 | 59篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 6篇 |
2014年 | 12篇 |
2013年 | 24篇 |
2012年 | 40篇 |
2011年 | 28篇 |
2010年 | 20篇 |
2009年 | 18篇 |
2008年 | 17篇 |
2007年 | 18篇 |
2006年 | 10篇 |
2005年 | 15篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
排序方式: 共有305条查询结果,搜索用时 15 毫秒
71.
72.
Behzat Altural Yunus Akcamur Emin Saripinar Ismail Yildirim Gert Kollenz 《Monatshefte für Chemie / Chemical Monthly》1989,120(11):1015-1020
Summary 4-Benzoyl-5-phenylfuran-2,3-dione (1) and the semicarbazones2, ureas and thioureas6, respectively, combine with loss of water and carbondioxide yielding the 1H-pyrimidine derivatives3 and7, respectively, in moderate yields (30–75%). Hydrolysis of3 b leads to the 1-amino-pyrimidine-2-one4.Cordially dedicated to o. Univ.-Prof. Dr. Hans Junek on the occasion of his 60th birthday 相似文献
73.
Ayhan
zmen Asli Karaka Ülfet Atav Yusuf Yakar 《International journal of quantum chemistry》2003,91(1):13-19
A general analytic formula is obtained for the two‐center Coulomb integrals over Slater‐type orbitals in elliptical coordinates. Finite series expansions are used in the evaluation of the radial part of the integrals. The analytic formula is expressed in terms of a product of the well‐known auxiliary functions Ak(p) and Bk(p) and incomplete gamma functions. Recursive relations for the computer evaluation of these functions are given as well. The recursive relations are stable and our computer results are in good agreement with the benchmark values given in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 相似文献
74.
Yildirim Aydogdu Ali Sadi Turabi Mediha Kok Ayse Aydogdu Hirobumi Tobe Haluk Ersin Karaca 《Applied Physics A: Materials Science & Processing》2014,117(4):2073-2078
The effects of the substitution of gallium with boron on the physical, mechanical and magnetic shape memory properties of Ni51Mn28.5Ga20.5?x B x (at.%) (x = 0, 1, 2, 3) polycrystalline alloys are investigated. It has been found that transformation temperatures are decreasing while hardness is increasing with boron addition. B-doping of NiMnGa alloys results in the formation of a second phase that increases its ductility and strength in compression. Moreover, saturation magnetization of austenite is decreasing, while Curie temperature of austenite is increasing with B-doping. 相似文献
75.
76.
Ilknur Yildirim Sarah Crotty Claas H. Loh Grit Festag Christine Weber Pier‐Francesco Caponi Michael Gottschaldt Matthias Westerhausen Ulrich S. Schubert 《Journal of polymer science. Part A, Polymer chemistry》2016,54(3):437-448
A simple and convenient method for the synthesis of end functionalized polylactides (PLAs) under mild conditions by ring opening polymerization (ROP) in the absence of potentially toxic catalysts is described. Various alcohols were used as initiators in combination with Ca[N(SiMe3)2]2(THF)2 as the precatalyst in THF at room temperature. Tailored end functionalities were obtained in a controlled fashion. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐ToF‐MS) and electrospray ionization quadrupole time of flight mass spectrometry (ESI‐Q‐ToF‐MS) analysis were performed to investigate the end groups. The results confirmed that the end group fidelity was maintained in the isolated PLAs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 437–448 相似文献
77.
F. Marinetti E. Coccia E. Bodo F. A. Gianturco E. Yurtsever M. Yurtsever E. Yildirim 《Theoretical chemistry accounts》2007,118(1):53-65
Ab initio potentials are computed for alkali metal cationic partners interacting with 4He and an overall many-body potential is constructed for each of the ionic dopants in helium clusters. The structures are
then obtained via a genetic algorithm approach and results compared with Basin-Hopping Monte Carlo simulations. The classical
arrangements are analyzed and quantum effects discussed in comparison with what has been found with Diffusion Monte Carlo
calculations. Further corrections to the classical picture by including three-body forces and radial delocalization of the
helium adatoms are also considered and their effects analyzed.
This work is dedicated to the late Nando Bernardi, an eclectic and gifted scientist and a dear friend whose early departure
has left a sad void in our community. 相似文献
78.
Thermally curable naphthoxazine-functionalized polymers were synthesized by the reaction of linear (diamines) and branched (triamines) poly(propyleneoxide)s (Jeffamine series) having various molecular weights, with p-formaldehyde, and 2-naphthol. The structures of the resulting polymers were characterized by using FT-IR and 1H-NMR. In addition, curing behavior of these polymers was studied using differential scanning calorimeter (DSC). Hydrophilicity of these polymers, both in cured and non-cured states, was investigated by water contact angle measurements. The surface topographies of the polymers were also examined by atomic force microscope (AFM). 相似文献
79.
Eda Cagli Erol Yildirim Shuo‐Wang Yang Irem Erel‐Goktepe 《Journal of Polymer Science.Polymer Physics》2019,57(4):210-221
Besides temperature, self‐aggregation of poly(2‐isopropyl‐2‐oxazoline) (PIPOX) can also be triggered via pH in aqueous solution (25 °C, pH > 5). Lowest energy structures and interaction energies of PIPOX with H3O+, OH?, and H2O were calculated by DFT methods showed that, in addition to their ability to protonate PIPOX, H3O+ ions had strong interaction with both water and PIPOX in acidic conditions. H3O+ ions acted as compatibilizer between PIPOX and water and increased the solubility of PIPOX. OH? ions were found to have stronger interaction with water compared to PIPOX resulting in desorption of water molecules from PIPOX phase and decreased solubility, leading to enhanced hydrophobic interactions among isopropyl groups of PIPOX and formation of aggregates at high pH. Results concerning the effect of end‐groups on aggregate size were in good agreement with statistical mechanics calculations. Moreover, the effect of polymer concentration on the aggregate size was examined. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 210–221 相似文献
80.
Handan Yildirim Abdelkader Kara Talat S. Rahman Rolf Heid Klaus-Peter Bohnen 《Surface science》2010,604(3-4):308-317
We present vibrational dynamics and thermodynamics for the (1 0 0) surfaces of Cu, Ag, Pd, Pt and Au using a real space approach. The force field for these systems is described by density functional theory. The changes in the vibrational dynamics and thermodynamics from those in bulk are confined mostly to the first-layer. A substantial enhancement of the low-frequency end of the acoustic branch was found and is related to a loosening of the bond at the surface. The thermodynamics of the first-layer also show significant differences (higher heat capacity, lower free energy and higher mean vibrational square amplitudes) from what obtains in bulk. Comparing these results with those calculated using embedded-atom method potentials, we discovered that for Ag(1 0 0) and Cu(1 0 0), the two methods yield very similar results while for Pd(1 0 0), Pt(1 0 0) and Au(1 0 0) there are substantial differences. 相似文献