全文获取类型
收费全文 | 3960篇 |
免费 | 164篇 |
国内免费 | 173篇 |
专业分类
化学 | 1463篇 |
晶体学 | 29篇 |
力学 | 294篇 |
综合类 | 12篇 |
数学 | 666篇 |
物理学 | 1833篇 |
出版年
2024年 | 3篇 |
2023年 | 27篇 |
2022年 | 39篇 |
2021年 | 39篇 |
2020年 | 62篇 |
2019年 | 69篇 |
2018年 | 64篇 |
2017年 | 83篇 |
2016年 | 124篇 |
2015年 | 109篇 |
2014年 | 172篇 |
2013年 | 227篇 |
2012年 | 181篇 |
2011年 | 346篇 |
2010年 | 266篇 |
2009年 | 337篇 |
2008年 | 318篇 |
2007年 | 309篇 |
2006年 | 267篇 |
2005年 | 189篇 |
2004年 | 150篇 |
2003年 | 145篇 |
2002年 | 151篇 |
2001年 | 78篇 |
2000年 | 63篇 |
1999年 | 72篇 |
1998年 | 53篇 |
1997年 | 35篇 |
1996年 | 24篇 |
1995年 | 36篇 |
1994年 | 23篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 23篇 |
1990年 | 13篇 |
1989年 | 25篇 |
1988年 | 8篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 18篇 |
1975年 | 5篇 |
1973年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有4297条查询结果,搜索用时 375 毫秒
31.
We explore the magnetic heat capacity in exchange-biased ferromagnet/antiferromagnet bilayers theoretically. We show that changes in the antiferromagnetic structure due to the reversal of the ferromagnet layer can be detected by distinct features in the heat capacity. This offers a method for probing antiferromagnetic domains in exchange-biased systems. 相似文献
32.
Takuya Hashimoto Koichi Kitazawa Masaaki Nakabayashi Tadashi Shiraishi Youichi Suemune Takakazu Yamamoto Hideomi Koinuma 《应用有机金属化学》1991,5(4):325-330
For low-temperature deposition of oxide films relating to Bi-Sr-Ca-Cu-O superconductors, photo-absorption and -decomposition properties were examined with respect to copper and alkaline-earth ß-diketonates. It was confirmed that all ß-diketonates examined were promising as source materials for photochemical vapour deposition (photo-CVD) using a low-pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600 °C. By combining two sources, Ca2CuO3 and SrCuO2 films were prepared. Photo-CVD of c-axis oriented Bi2Sr2CuOx film was achieved by the irradiation of ternary sources of Bi(C6H5)3 and strontium and copper ß-diketonates at 500 °C. 相似文献
33.
F.T. Yuan S.K. Chen W.M. Liao C.W. Hsu S.N. Hsiao W.C. Chang 《Journal of magnetism and magnetic materials》2006
The Au/FePt samples were prepared by depositing a gold cap layer at room temperature onto a fully ordered FePt layer, followed by an annealing at 800 °C for the purpose of interlayer diffusion. After the deposition of the gold layer and the high-temperature annealing, the gold atoms do not dissolve into the FePt Ll0 lattice. Compared with the continuous FePt film, the TEM photos of the bilayer Au(60 nm)/FePt(60 nm) show a granular structure with FePt particles embedded in Au matrix. The coercivity of Au(60 nm)/FePt(60 nm) sample is 23.5 kOe, which is 85% larger than that of the FePt film without Au top layer. The enhancement in coercivity can be attributed to the formation of isolated structure of FePt ordered phase. 相似文献
34.
Wenran Feng Chizi Liu Guangliang Chen Guling Zhang Weichao Gu Erwu Niu Si-Ze Yang 《Applied Surface Science》2007,253(11):4923-4927
Hard films prepared by pulsed high energy density plasma (PHEDP) are characterized by high film/substrate adhesive strength, and high wear resistance. Titanium carbonitride (TiCN) films were deposited onto YG11C (ISO G20) cemented carbide cutting tool substrates by PHEDP at room temperature. XRD, XPS, SEM, AES, etc. were adopted to analyze the phases (elements) composition, microstructure and the interface of the films, respectively. The results show that, the uniform dense films are composed of grains ranging from 70 to 90 nm. According to the AES result, there is a broad transition layer between the film and the substrate, due to the ion implantation effect of the PHEDP. The transition layer is favorable for the film/substrate adhesion. 相似文献
35.
36.
37.
We shall prove here that any binary relation on a base E with cardinality n > 6 is reconstructible from its restrictions of cardinality 2, 3, 4 and (n - 1). This proof needs results of part I of this paper where we characterize any pair of relations R, R' which are 2-, 3- and 4-hypomorphic. As a corollary we obtain that any binary relation is (n - 4)-reconstructible (when n > 9). 相似文献
38.
K.R. Murali 《Journal of Physics and Chemistry of Solids》2007,68(12):2293-2296
Zinc oxide (ZnO) films were deposited on glass substrates by the sol-gel dip coating method using acrylamide route. The films were characterized by X-ray diffraction studies which indicated wurtzite structure. Optical absorption measurements indicated band gap in the range 3.17-3.32 eV. XPS studies indicated the formation of ZnO. The resistivity of the films were in the range 1000-10,000 ohm cm. 相似文献
39.
FexNi100−x nanometric films were deposited on SiO2/Si substrates at room temperature using the pulsed laser deposition technique. The targets were Fe-Ni amorphous magnetic foils with composition Fe50Ni50, Fe35Ni65 and Fe22Ni78. Morphological and structural properties of the deposited films were investigated using scanning electron microscopy, Rutherford backscattering spectrometry, grazing incidence X-ray diffraction, and X-ray reflectivity. Electrical and magnetic characteristics of the films were investigated by using the four-point probe and the magneto-optic Kerr effect techniques, respectively. The film properties are strictly dependent on the Fe-Ni compositional ratio. 相似文献
40.