全文获取类型
收费全文 | 1092篇 |
免费 | 21篇 |
国内免费 | 7篇 |
专业分类
化学 | 829篇 |
晶体学 | 11篇 |
力学 | 40篇 |
数学 | 48篇 |
物理学 | 192篇 |
出版年
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 18篇 |
2018年 | 11篇 |
2016年 | 11篇 |
2015年 | 13篇 |
2014年 | 16篇 |
2013年 | 69篇 |
2012年 | 52篇 |
2011年 | 51篇 |
2010年 | 43篇 |
2009年 | 41篇 |
2008年 | 68篇 |
2007年 | 62篇 |
2006年 | 53篇 |
2005年 | 60篇 |
2004年 | 48篇 |
2003年 | 47篇 |
2002年 | 57篇 |
2001年 | 18篇 |
2000年 | 14篇 |
1999年 | 11篇 |
1998年 | 15篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 18篇 |
1986年 | 9篇 |
1985年 | 15篇 |
1984年 | 20篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1972年 | 11篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1966年 | 7篇 |
排序方式: 共有1120条查询结果,搜索用时 15 毫秒
111.
Y. Ota M. Machida T. Koyama 《Physica C: Superconductivity and its Applications》2011,471(21-22):760-762
We construct a theory of dynamical behavior in intrinsic Josephson junction stacks with multigap superconducting layers. The theory predicts the existence of two kinds of phase modes, one of which is the Josephson-plasma mode and other of which is the Leggett’s mode. We discuss a cooperative phenomena induced by inter-band Josephson coupling in addition to capacitive and inductive couplings between the superconducting layers. 相似文献
112.
Tsunewaki K 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2011,87(8):529-549
A homology search of wheat chloroplast (ct) and mitochondrial (mt) genomes identified 54 ctDNA segments that have homology with 66 mtDNA segments. The mtDNA segments were classified according to their origin: orthologs (prokaryotic origin), xenologs (interorganellar DNA transfer origin) and paralogs (intraorganellar DNA amplification origin). The 66 mtDNA sequences with homology to ctDNA segments included 14 paralogs, 18 orthologs and 34 xenologs. Analysis of the xenologs indicated that the DNA transfer occurred unidirectionally from the ct genome to the mt genome. The evolutionary timing of each interorganellar DNA transfer that generated a xenolog was estimated. This analysis showed that 2 xenologs originated early in green plant evolution, 4 in angiosperm evolution, 3 in monocotyledon evolution, 9 during cereal diversification and 8 in the evolution of wheat. Six other xenologs showed recurrent transfer from the ct to mt genomes in more than one taxon. The two remaining xenologs were uninformative on the evolutionary timing of their transfer. The wheat mt nad9 gene was found to be chimeric, consisting of the cereal nad9 gene and its 291 bp 5'-flanking region that included a 58 bp xenolog of the ct-ndhC origin. 相似文献
113.
G. Rajesh M. Arivanandhan H. Morii T. Aoki T. Koyama Y. Momose A. Tanaka T. Ozawa Y. Inatomi Y. Hayakawa 《Journal of Crystal Growth》2010,312(19):2677-2682
Dissolution process of GaSb into InSb melt was observed by an X-ray penetration method. The intensity of X-rays penetrated through the rectangular shaped GaSb (seed)/InSb/GaSb (feed) sandwich sample was recorded by the CdTe line sensor detector. The penetrated X-ray intensities and images of the sample were obtained as a function of time and temperature. The gallium (Ga) composition profile of the sample was calculated as a function of time by making the calibration line with the penetrated X-ray intensities of GaSb and InSb standard samples. The calculated Ga composition profile of the grown sample agreed well with the data measured by energy dispersive X-ray spectroscopy analysis. The result suggested that lower GaSb seed dissolved faster than upper GaSb feed despite of the low temperature at the lower GaSb seed. It clearly indicates that the solutal transport induced by gravity strongly affects the dissolution process. 相似文献
114.
115.
Radical additions of S-thiophosphinyl dithiocarbonate to terminal aromatic alkynes afford (E)-1-aryl-1-thio-2-thiophosphinylethene derivatives regio- and stereoselectively in high yields. The transformations of the products are also described. 相似文献
116.
Koichiro Ohtake 《代数通讯》2013,41(15):1533-1540
117.
118.
Masahiro Ishino Kaoru Kinoshita Kunio Takahashi Takashi Sugita Motoo Shiro Kimiko Hasegawa Kiyotaka Koyama 《Tetrahedron》2012,68(41):8572-8576
Three novel diterpenes, phomactins K–M (1–3), were isolated from the cultures of an unidentified marine-derived fungus. The structures of 1–3 were elucidated from spectroscopic data (NMR, MS, IR), and the absolute configurations of 1, 2, and the relative configuration of 3 were determined by X-ray diffraction analysis. 相似文献
119.
Ryota Seto Takashi Sato Takahiro Kojima Katsumoto Hosokawa Yasuhito Koyama Gen‐Ichi Konishi Toshikazu Takata 《Journal of polymer science. Part A, Polymer chemistry》2010,48(16):3658-3667
Syntheses of 2,2′‐bisalcoholic group‐substituted 9,9′‐spirobifluorene monomers 2 were performed by the reaction of 2,2′‐dihydroxy‐9,9′‐spirobifluorene 2a with haloalcohols. Polycarbonates consisting of 9,9′‐spirobifluorene skeleton in the main chain (PC 4 ) were synthesized by the polycondensation of 2,2′‐bisalcoholic monomers 2 and triphosgene or diphenyl carbonate. PC 4 showed good thermal stability: the 5% weight loss temperature was over 330 °C under both nitrogen and air atmospheres. The glass transition temperature was in a range of 16–269 °C estimated by differential scanning calorimetry, depending on the flexibility of the alkylene or oxyethylene chains of 2 . PC 4 showed high solubility toward ordinary organic solvents such as CHCl3, benzene, and THF, making possible the preparation of the flexible thin films. Very high refractive index in a range of 1.62–1.66 at 589 nm was observed although PC 4 consists only of C, H, and O atoms, whereas very low degree of birefringence was confirmed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3658–3667, 2010 相似文献