全文获取类型
收费全文 | 1048篇 |
免费 | 30篇 |
国内免费 | 10篇 |
专业分类
化学 | 883篇 |
晶体学 | 14篇 |
力学 | 8篇 |
数学 | 69篇 |
物理学 | 114篇 |
出版年
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 20篇 |
2014年 | 30篇 |
2013年 | 41篇 |
2012年 | 47篇 |
2011年 | 53篇 |
2010年 | 33篇 |
2009年 | 41篇 |
2008年 | 57篇 |
2007年 | 50篇 |
2006年 | 67篇 |
2005年 | 63篇 |
2004年 | 64篇 |
2003年 | 44篇 |
2002年 | 45篇 |
2001年 | 9篇 |
2000年 | 17篇 |
1999年 | 23篇 |
1998年 | 14篇 |
1997年 | 27篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 14篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1980年 | 14篇 |
1979年 | 24篇 |
1978年 | 9篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1975年 | 11篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 5篇 |
排序方式: 共有1088条查询结果,搜索用时 0 毫秒
1.
Application of the 19F NMR technique to observe binding of the general anesthetic halothane to human serum albumin. 总被引:1,自引:0,他引:1
Kazuaki Shikii Satoshi Sakurai Hiroaki Utsumi Hiroko Seki Mitsuru Tashiro 《Analytical sciences》2004,20(10):1475-1477
19F NMR techniques were employed to characterize the binding property of the widely used general anesthetic halothane with human serum albumin (HSA). It was found that 19F(1H) NOE and 2D 1H-19F HOESY experiments detected intermolecular NOEs between halothane 19F and HSA protons. Measurements of the diffusion coefficients for halothane were also carried out by 1H and 19F NMR, indicating the interaction of halothane with HSA. The present results indicate that these techniques are very suitable to identify a fluorine-containing ligand binding with a protein receptor in the drug-discovery process. 相似文献
2.
In order to change the ion-exchange selectivity of anion-exchange resin, the surface of a gel-type anion exchange resin was modified with anionic polyelectrolyte, polystyrenesulfonic acid. Using this modified resin, the ion-exchange rate of nitrate was little decreased, but that of sulfate was evidently decreased. It is considered that the ion-exchange reaction of the multivalent anion is suppressed by the greater electrostatic repulsive force against the modification layer than that against the monovalent anion. Thus, this modified resin may be suitable for the selective separation of monovalent anions. The influence of the modified condition on the ion-exchange rate was examined. Furthermore, this modified resin was used to separate nitrate ions from sulfate ions in the aqueous solution. 相似文献
3.
4.
Mitsuru Sugimoto 《Journal of Functional Analysis》1998,160(2):1
We discuss the problem of boundedness fromLp(Rn) toLp′(Rn) (1/p+1/p′=1, 1?p?2) of operators of the typeM=F−1ei?(ξ)a(ξ) F, which is related to the study of hyperbolic equations with constant coefficients. The boundedness is dependent on a geometrical property ofΣ=?−1(1), and its dependence has been exactly determined in the casesn=2, 1?p?2 andn?3,p=1, 2 (M. Sugimoto,Math. Z.215(1994), 519–531;222(1996), 521–531). This paper is devoted to the unsolved case 1<p<2, and a strange phenomenon is exhibited in the simplest casen=3. 相似文献
5.
Takanari Yasui Takeshi Ohtsuka Tetsu Suzuki Shigeki Okajima Kazuya Nakayama Mitsuru Tomioka Katsuhiro Kamimura Takeo Namekata Hiroaki Minamide Hiromasa Ito 《International Journal of Infrared and Millimeter Waves》2006,27(2):199-210
A new, wide-band, high-speed and high-sensitivity THz detector has been developed. The prototype detector consists of a parabolic
cylindrical mirror, a long wire antenna and a Schottky barrier diode. Direct detection measurements have shown a stable sensitivity
of 150 ± 50 V/W for 1–2 THz without any adjustments. The long wire antenna was fixed at the focus of parabolic cylindrical
mirror then it has been realized less operation steps, easy coupling to the external THz signals and a dramatic enhancement
in the practicality of this system. The optically polished mirror and frosted surface one showed comparable sensitivities,
thus easy polishing and less cost mirror fabrication can be applied for this system. The radiation pattern showed a maximum
radiation angle of approximately 23° with its dominant main lobe, which was attributed to the wire antenna character and confirmed
good agreements with classical antenna theory. 相似文献
6.
Mitsuru Ueda Tetsuya Abe Mitsuo Oda 《Journal of polymer science. Part A, Polymer chemistry》1992,30(9):1993-1998
Aromatic poly(thioether ketone)s were prepared by the direct polycondensation of aromatic dicarboxylic acids with aryl compounds containing ether or sulfide structures using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensation proceeded smoothly and produced aromatic poly(thioether ketone)s with inherent viscosities up to 0.73 dL/g. The synthesis of substituted aryl ketones by the reaction of substituted benzoic acids with aryl compounds in PMMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(thioether ketone)s showed a 10% weight loss in air and nitrogen at around 450 and 460°C, respectively. © 1992 John Wiley & Sons, Inc. 相似文献
7.
Katsuya Sakayori Yuji Shibasaki Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》2006,44(21):6385-6393
Poly(amic acid)s (PAAs) having the high solution stability and transmittance at 365 nm for photosensitive polyimides have been developed. PAAs with a twisted conformation in the main chains were prepared from 2,2′,6,6′‐biphenyltetracarboxylic dianhydride (2,2′,6,6′‐BPDA) and aromatic diamines. Imidization of PAAs was achieved by chemical treatment using trifluoroacetic anhydride. Among them, the PAA derived from 2,2′,6,6′‐BPDA and 4,4′‐(1,3‐phenylenedioxy)dianiline was converted to the polyimide by thermal treatment. The heating at 300 °C under nitrogen did not complete thermal imidization of PAAs having glass‐transition temperatures (Tg)s higher than 300 °C to the corresponding PIs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6385–6393, 2006 相似文献
8.
Shizuko Eguchi Mitsuru Nakayama Shûichi Hayashi 《Journal of mass spectrometry : JMS》1976,11(6):574-581
The doubly charged ion mass spectra of anhydropisatin, 4-methoxyanhydropisatin, 3, 8, 9-trimethoxypterocarpen and 3, 4, 8, 9-tetramethoxypterocarpen were determined, and the fragmentation was explained by assuming that the paired electrons were partially localized in the fragmentations and by comparing the spectra with that of 3-(CD3)-anhydropisatin. Conventional mass spectra of these compounds were very simple, but the doubly charged ion spectra were sufficiently characteristic for the reliable identification. 相似文献
9.
10.