全文获取类型
收费全文 | 93篇 |
免费 | 2篇 |
专业分类
化学 | 58篇 |
晶体学 | 7篇 |
力学 | 1篇 |
综合类 | 2篇 |
物理学 | 27篇 |
出版年
2017年 | 1篇 |
2016年 | 1篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有95条查询结果,搜索用时 343 毫秒
71.
Nina G. Furmanova Natalya I. Sorokina Valery I. Andrianov Ursula Bologa Alexandru T. Balaban 《Structural chemistry》1991,2(7):651-654
The structure of 1-(3,5-dimethyl-2-furyl)-3-(p-tolyl)-prop-2-en-1-one, C16H16O2 is determined by single-crystal x-ray diffractometry. Crystals are triclinic,
, a=7.381(7), b=8.871(5), c=10.745(13) Å, =93.53(7), =102.25(8),=95.43(7)°, V=682(1) Å3, Z=2, dcalc=1.170 g cm–3, (Cu K)=1.54178 Å,=5.697 cm–1, M=270.30, F(000)=256, R=0.077 for 1601 unique observed reflections. The trans-geometry of the C=C double bond, thes-cis-geometry of the C=C-C=O moiety, and thes-trans arrangement of the carbonyl and furane oxygen atoms are proved. 相似文献
72.
P. N. Bourosh O. A. Bologa Yu. A. Simonov G. Bocelli N. V. Gerbeleu 《Russian Journal of Coordination Chemistry》2005,31(9):641-644
The [Co(DH)2(Py)2][H2F3] complex (DH? is the dimethylglyoxime residue) is synthesized and studied by X-ray diffraction analysis. Structural units of the crystal are complex cations [Co(DH)2(Py)2]+ and anions [H2F3]?. Two residues of α-dimethylglyoxime linked by intramolecular hydrogen bonds O-H?O lie in the equatorial plane of the octahedral Co(III) complex, and two pyridine molecules occupy the apical positions. The H2F 3 ? anion is formed due to the association of the F? ion with two HF molecules through hydrogen bonds F-H?F. Weak intermolecular interactions C-H?F and C-H?O are observed in the crystal. The problem of the influence of these interactions on the packing of the complexes in crystal is discussed. 相似文献
73.
74.
75.
S. T. Malinovskii O. A. Bologa É. B. Coropceanu N. V. Gerbeleu 《Crystallography Reports》2004,49(5):807-810
The crystal structure of a new mixed-ligand complex [Co(DH)(o-phen)2][BF4]2 · 2H2O is determined by X-ray diffraction. The crystal is monoclinic, a = 12.2081(11) Å, b = 14.3474(9) Å, c = 17.7393(16) Å, β = 104.95(1)°, and space group P21/c. The coordination octahedron of Co3+ is formed by two nitrogen atoms of the dimethylglyoxime molecule and four nitrogen atoms of o-phenanthroline molecules. The dimethylglyoxime molecule is singly deprotonated and acts as DH?. The mean Co-N distances for dioxime and o-phenanthroline are 1.911 and 1.964 Å, respectively. The key role in the formation of the crystal structure is played by [BF4]? outer-sphere anions and crystallization water molecules, which form an extended hydrogen-bond system. 相似文献
76.
采用逐步蔓延采样点和三角形的方法,给出了3个算法用于隐函数曲面的采样和三角化,这些算法使得隐函数曲面的重复绘制和控制都能实时进行,其采样方法具有局部适应性,能随着曲率的变化自动控制采样点的疏密程度,从而使得采样点尽量少,但又不至于遗漏表面细节,提出的三角化方法能用于其它散乱数据点的表面重构,它的算法复杂度仅为O(n)。 相似文献
77.
78.
79.
80.
Koster S Duursma MC Boon JJ Nielen MW de Koster CG Heeren RM 《Journal of mass spectrometry : JMS》2000,35(6):739-748
The molecular structure of a series of homo- and copolyesters was studied using sustained off-resonance irradiation collisionally activation dissociation on a Fourier transform ion cyclotron resonance mass spectrometer. Electrospray ionization was used as an ionization technique. The most important fragmentation pathways of the homopolyesters poly(dipropoxylated bisphenol-A/adipic acid) and poly(dipropoxylated bisphenol-A/isophthalic acid) were studied. Six different dissociation mechanisms were observed which are very similar to the mechanisms found to occur during pyrolysis of these compounds. Four of these mechanisms are a result of cleavages of the ester bond and the others are due to cleavages of the ether bond or bisphenol-A unit. Some of the fragments expected are not present in the spectrum, indicating that each fragment has a specific sodium affinity. Sequence-specific fragments of two of the three copolyester sequences that theoretically can exist were experimentally observed. Fragments that originate from the third sequence are not unique and can also be formed from other sequences. Therefore, it was not possible to determine the presence of the third sequence. Copyright 2000 John Wiley & Sons, Ltd. 相似文献