全文获取类型
收费全文 | 5796篇 |
免费 | 147篇 |
国内免费 | 22篇 |
专业分类
化学 | 4186篇 |
晶体学 | 67篇 |
力学 | 56篇 |
综合类 | 2篇 |
数学 | 374篇 |
物理学 | 1280篇 |
出版年
2023年 | 36篇 |
2022年 | 42篇 |
2021年 | 47篇 |
2020年 | 78篇 |
2019年 | 78篇 |
2018年 | 63篇 |
2017年 | 31篇 |
2016年 | 93篇 |
2015年 | 123篇 |
2014年 | 113篇 |
2013年 | 300篇 |
2012年 | 265篇 |
2011年 | 291篇 |
2010年 | 176篇 |
2009年 | 193篇 |
2008年 | 274篇 |
2007年 | 319篇 |
2006年 | 289篇 |
2005年 | 317篇 |
2004年 | 271篇 |
2003年 | 244篇 |
2002年 | 239篇 |
2001年 | 131篇 |
2000年 | 130篇 |
1999年 | 95篇 |
1998年 | 68篇 |
1997年 | 57篇 |
1996年 | 92篇 |
1995年 | 60篇 |
1994年 | 58篇 |
1993年 | 74篇 |
1992年 | 76篇 |
1991年 | 74篇 |
1990年 | 62篇 |
1989年 | 58篇 |
1988年 | 60篇 |
1987年 | 64篇 |
1986年 | 54篇 |
1985年 | 101篇 |
1984年 | 89篇 |
1983年 | 50篇 |
1982年 | 64篇 |
1981年 | 57篇 |
1980年 | 73篇 |
1979年 | 76篇 |
1978年 | 52篇 |
1977年 | 36篇 |
1976年 | 43篇 |
1974年 | 50篇 |
1973年 | 35篇 |
排序方式: 共有5965条查询结果,搜索用时 15 毫秒
21.
Hiroshi Sato 《Journal of Theoretical Probability》1992,5(2):349-353
The aim of this paper is to characterize the nuclearity of an integral operator, defined by a continuous non-negative definite square integrable kernel on a separable metric space, in terms of the integrability of the trace of the kernel function. Nuclearity here plays a role forU-statistics. 相似文献
22.
In Homma M and Kim SJ [2], the authors considered two-point codes on a Hermitian curve defined over fields of odd characteristic.
In this paper, we study the geometry of a Hermitian curve over fields of even characteristic and classify the two-point codes
whose minimum distances agree with the designed ones. 相似文献
23.
Toshiyuki Oyama Akira Kitamura Eiichi Sato Masao Tomoi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2694-2706
The factors affecting pattern‐forming properties in reaction development patterning were examined with polyarylates with various bisphenol moieties. The developability of the photosensitive polyarylates was dependent on the properties of the subtituent (R) in the bisphenol moieties. The development time decreased in the following order: R?C(CH3)2 > fluorenyl unit ? phenolphthalein unit > C(CF3)2 > SO2. This order agreed with that of the reactivity between the polyarylates and ethanolamine, and these orders can be explained by pKa of the bisphenol used to prepare the polyarylates. The development with NH2? R′? OH resulted in successful positive‐tone pattern formation. However, pattern formation with the developers containing NH2? R′? OCH3 was unsuccessful. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2694–2706, 2006 相似文献
24.
Yasutada Suzuki Masatoshi Endo Jiye Jin Kenji Iwase Masaaki Iwatsuki 《Analytical sciences》2006,22(3):411-414
Tristimulus colorimetry using a digital still camera (DSC) as a colorimeter has been developed. A photograph of a sample and standard solutions was taken simultaneously with the DSC, and it was transferred to a PC. On the PC, the colors of the sample and of the standard solutions were analyzed and L* (brightness), a* (red-green component), and b* (yellow-blue component) values were determined with laboratory-made software. A dedicated light-box containing white-color LEDs as light source was made of white acrylic to make constant exposure at each photograph. Various settings of the DSC, such as exposure mode, white balance, and so on, that affect analytical figures, were studied with determination of iron with 1,10-phenanthroline. This method was successfully applied to the determinations of iron in a river water sample and of residual chlorine in tap water samples with N,N-diethylphenylenediamine (DPD). 相似文献
25.
In this study, we attempted to control the timing of light-emission from bioluminescent bacteria, by changed cell numbers inoculated into medium. Luminous bacteria express bioluminescence when the number of cells reached a threshold. Inoculated cell density had an effect on the time of bioluminescence starting. Samples were prepared by varying cell density of inoculation. In the results, all the vials showed different luminescence profiles in the order of inoculated cell population. 相似文献
26.
27.
28.
Bond IA Budding E Conway MJ Fenton KB Fujii H Fujii Z Fujimoto M Hasegawa H Hayashida N Honda M Hotta N Humble JE Kabe S Kasahara K Kifune T Masaike A Matsubara Y Mitsui K Miura Y Mori M Murakami K Muraki Y Nagano M Nakamura K Nakamura T Norris PM Ohashi Y Okada A Saito T Sakata M Sato H Shibata S Shima M Storey JR Tanimori T Teshima M Torii S Uchino K Watase Y Woodhams MD Yamamoto Y Yock PC Yuda T 《Physical review letters》1988,61(20):2292-2295
29.
30.
Diamond-like carbon films prepared by pulsed-laser evaporation 总被引:1,自引:0,他引:1
T. Sato S. Furuno S. Iguchi M. Hanabusa 《Applied Physics A: Materials Science & Processing》1988,45(4):355-360
Diamond-like carbon thin films were prepared by pulsed-laser evaporation. In this method a carbon target was irradiated by a XeCl laser with a power density of 3×108 W/cm2 and carbon atoms, together with a small number of ions, were produced. Deposition rates and film properties changed sensitively with substrate temperature. The films deposited at 50°C were diamond-like, having reasonable hardness, high refractive index (2.1–2.2 at 633 nm), optical transparency in the infrared, electrical resistivity of 108 cm and chemical inertness (no dissolution in a HFHNO3 solution). The band gap measured from optical absorption was 1.4 eV. Raman spectrum and infrared absorption, whose features varied with the substrate temperature, were also measured. The films were amorphous and no crystallinity was observed, as confirmed by x-ray diffraction, transmission electron diffraction and Raman spectroscopy. Hydrogen atoms were incorporated in the films with a typical H/C ratio of 0.3. The application of a negative bias to the substrate modified the deposition due to the presence of ions. 相似文献