全文获取类型
收费全文 | 5065篇 |
免费 | 136篇 |
国内免费 | 7篇 |
专业分类
化学 | 3707篇 |
晶体学 | 69篇 |
力学 | 60篇 |
综合类 | 2篇 |
数学 | 188篇 |
物理学 | 1182篇 |
出版年
2023年 | 27篇 |
2022年 | 41篇 |
2021年 | 41篇 |
2020年 | 74篇 |
2019年 | 79篇 |
2018年 | 55篇 |
2017年 | 29篇 |
2016年 | 92篇 |
2015年 | 111篇 |
2014年 | 100篇 |
2013年 | 238篇 |
2012年 | 244篇 |
2011年 | 252篇 |
2010年 | 154篇 |
2009年 | 167篇 |
2008年 | 240篇 |
2007年 | 285篇 |
2006年 | 262篇 |
2005年 | 289篇 |
2004年 | 217篇 |
2003年 | 202篇 |
2002年 | 204篇 |
2001年 | 116篇 |
2000年 | 118篇 |
1999年 | 74篇 |
1998年 | 55篇 |
1997年 | 51篇 |
1996年 | 89篇 |
1995年 | 56篇 |
1994年 | 54篇 |
1993年 | 67篇 |
1992年 | 72篇 |
1991年 | 65篇 |
1990年 | 54篇 |
1989年 | 57篇 |
1988年 | 54篇 |
1987年 | 58篇 |
1986年 | 51篇 |
1985年 | 92篇 |
1984年 | 76篇 |
1983年 | 43篇 |
1982年 | 52篇 |
1981年 | 49篇 |
1980年 | 58篇 |
1979年 | 56篇 |
1978年 | 47篇 |
1977年 | 33篇 |
1976年 | 39篇 |
1974年 | 27篇 |
1973年 | 28篇 |
排序方式: 共有5208条查询结果,搜索用时 7 毫秒
21.
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
22.
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
23.
24.
25.
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
26.
27.
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
28.
29.
30.
Jin Y Yamanaka J Sato S Miyata I Yomota C Yonese M 《Chemical & pharmaceutical bulletin》2002,50(10):1341-1348
Hyaluronate-hydroxyethyl acrylate blend gel (HA-PHEA) were prepared to modify the brittleness of hyaluronate gel (HA) and the characteristics of HA-PHEA gel were compared with those of HA and polyhydroxyethyl acrylate (PHEA) gels. These gels were high in water content and transparent. HA-PHEA gel was improved in viscoelastic properties due to the elasticity and the high affinity with water of PHEA, and the drying-swelling cycles became reversible. The effective charge densities theta of the gels estimated from membrane potentials were -0.002, -0.008 and 0 mol dm(-3) for HA-PHEA, HA and PHEA gels. Effects of electro- static and nonelectrostatic interactions on absorptions and releases were studied using sodium benzoate (NaBA) as an anionic solute, and methylene blue (MB), chlorpromazine (CPHCl) and benzethonium chloride (BZTCl) as cationic solutes, in which CPHCl and BZTCl are cationic amphiphilic solutes. The releases of MB, CPHCl and BZTCl from HA-PHEA and HA gels were suppressed comparing with those of NaBA. By adding salts, the releases of MB and CPHCl were enhanced but those of BZTCl were suppressed due to enhancement of the intra- and intermicelle formation. In the releases of the cationic solutes from HA-PHEA gel, electrostatic and nonelectrostatic interactions with HA were found to play important roles. Behaviors of the releases from HA-PHEA gel were found to possess the features of HA gel. 相似文献