全文获取类型
收费全文 | 4866篇 |
免费 | 172篇 |
国内免费 | 8篇 |
专业分类
化学 | 3594篇 |
晶体学 | 58篇 |
力学 | 57篇 |
综合类 | 2篇 |
数学 | 181篇 |
物理学 | 1154篇 |
出版年
2023年 | 27篇 |
2021年 | 40篇 |
2020年 | 72篇 |
2019年 | 78篇 |
2018年 | 56篇 |
2017年 | 26篇 |
2016年 | 94篇 |
2015年 | 113篇 |
2014年 | 92篇 |
2013年 | 246篇 |
2012年 | 244篇 |
2011年 | 264篇 |
2010年 | 150篇 |
2009年 | 163篇 |
2008年 | 233篇 |
2007年 | 274篇 |
2006年 | 250篇 |
2005年 | 263篇 |
2004年 | 207篇 |
2003年 | 185篇 |
2002年 | 184篇 |
2001年 | 115篇 |
2000年 | 120篇 |
1999年 | 79篇 |
1998年 | 56篇 |
1997年 | 44篇 |
1996年 | 82篇 |
1995年 | 56篇 |
1994年 | 54篇 |
1993年 | 68篇 |
1992年 | 66篇 |
1991年 | 63篇 |
1990年 | 51篇 |
1989年 | 54篇 |
1988年 | 51篇 |
1987年 | 54篇 |
1986年 | 46篇 |
1985年 | 88篇 |
1984年 | 68篇 |
1983年 | 39篇 |
1982年 | 53篇 |
1981年 | 43篇 |
1980年 | 56篇 |
1979年 | 55篇 |
1978年 | 46篇 |
1977年 | 34篇 |
1976年 | 40篇 |
1975年 | 27篇 |
1974年 | 33篇 |
1973年 | 28篇 |
排序方式: 共有5046条查询结果,搜索用时 15 毫秒
41.
The analytical method using transfer function or impulse response is very effective for analyzing non-linear systems with localized non-linearities. This is because the number of non-linear equations can be reduced to that of the equations with respect to points connected with the non-linear element. In the present paper, analytical method for the steady state vibration of non-linear system including subharmonic vibration is proposed by utilizing convolution integral and the impulse response. The Galerkin method is introduced to solve the non-linear equations formulated by the convolution integral, and then the steady state vibration is obtained. An advantage of the present method is that stability or instability of the steady state vibration can be discriminated by the transient analysis from convolution integral. The three-degree-of-freedom mass-spring system is shown as a numerical example and the proposed method is verified by comparing with the result by Runge-Kutta-Gill method. 相似文献
42.
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
43.
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
44.
45.
Haruo Sato 《Hyperfine Interactions》1990,57(1-4):2089-2094
Mössbauer spectra of ferrocene adsorbed on silica gel were measured in order to study the state of adsorption. Ferrocene adsorbed on silica gel tended to oxidize in air and form ferricenium ion. It is assumed that the oxidation of adsorbed ferrocene was caused by surface hydroxyls on the silica gel and O2 in air. It was observed that ferrocene adsorbed weakly at 293 K, although the ferricenium ion adsorbed strongly at 293 K. Thus the adsorption states of ferrocene depend on the experimental condition. 相似文献
46.
47.
48.
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
49.
50.
Adachi I Aihara H Dijkstra HB Enomoto R Fujii H Fujii K Fujii T Fujimoto J Fujiwara N Hayashii H Higashi S Iida N Imanishi A Ikeda H Ishii T Itoh R Iwasaki H Iwata S Kajikawa R Kamae T Kato S Kawabata S Kichimi H Kishida T Kobayashi M Kuroda S Kusuki N Maruyama A Maruyama K Masuda H Matsuda T Miyamoto A Morimoto T Nakamura K Nitoh O Noguchi S Ochiai F Okuno H Okusawa T Ohshima T Ozaki H Sato T Sai F Shimonaka J Shimozawa K Shirahashi A Sugahara R Sugiyama A Suzuki S Suwada T Takahashi K 《Physical review letters》1988,60(2):97-100