全文获取类型
收费全文 | 742篇 |
免费 | 23篇 |
国内免费 | 1篇 |
专业分类
化学 | 544篇 |
晶体学 | 5篇 |
力学 | 9篇 |
数学 | 65篇 |
物理学 | 143篇 |
出版年
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 10篇 |
2013年 | 40篇 |
2012年 | 36篇 |
2011年 | 46篇 |
2010年 | 28篇 |
2009年 | 22篇 |
2008年 | 36篇 |
2007年 | 49篇 |
2006年 | 58篇 |
2005年 | 54篇 |
2004年 | 39篇 |
2003年 | 39篇 |
2002年 | 32篇 |
2001年 | 13篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 10篇 |
1984年 | 16篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1964年 | 3篇 |
排序方式: 共有766条查询结果,搜索用时 0 毫秒
141.
In an effort to improve and simplify refractive index sensors, we identified a basic operation mode at the critical angle. Sensitivity to the refractive index is higher than in standard surface plasmon resonance sensors, and we have been able to demonstrate analytically that it is virtually an unbounded value. We describe this approach and submit a complete analytical study demonstrating its unlimited sensing power. To test the approach, we constructed an economical and basic sensor. Despite its simplicity, we demonstrated the discrimination capability to be of the order of 10(-6), as far as we know close to the best sensitivity ever recorded. This detection method is generally applicable to any optical system and may pave the way for the next generation of optical sensing devices. 相似文献
142.
Zhou XJ Shi J Yoshida T Cuk T Yang WL Brouet V Nakamura J Mannella N Komiya S Ando Y Zhou F Ti WX Xiong JW Zhao ZX Sasagawa T Kakeshita T Eisaki H Uchida S Fujimori A Zhang Z Plummer EW Laughlin RB Hussain Z Shen ZX 《Physical review letters》2005,95(11):117001
High resolution angle-resolved photoemission spectroscopy data along the (0,0)-(pi,pi) nodal direction with significantly improved statistics reveal fine structure in the electron self-energy of the underdoped (La2-xSrx)CuO4 samples in the normal state. Fine structure at energies of (40-46) meV and (58-63) meV, and possible fine structure at energies of (23-29) meV and (75-85) meV, have been identified. These observations indicate that, in (La2-xSrx)CuO4, more than one bosonic modes are involved in the coupling with electrons. 相似文献
143.
Hirano A Yoshikawa H Matsushita S Yamada Y Shiraki K 《Langmuir : the ACS journal of surfaces and colloids》2012,28(8):3887-3895
Nanoparticles taken into biological systems can have biological impacts through their interactions with cell membranes, accompanied by protein adsorption onto the nanoparticle surfaces, forming a so-called protein corona. Our current research aims to demonstrate that nanoscale protein aggregates behave like such nanoparticles with regard to the interaction with lipid membranes. In this study, the adsorption and disruption of the lipid membranes by protein aggregates were investigated using amyloid fibrils and nanoscale thermal aggregates of lysozyme. Both types of protein aggregates had disruptive effects on the negatively charged liposomes, similar to polycationic nanoparticles. Interestingly, adsorption of liposomes on the amyloid fibrils preceding disruption occurred even if the net charge of the liposome was zero, suggesting the importance of hydrophobic interactions in addition to electrostatic interactions. The results of the present study provide new insights into the biological impacts of nanoparticles in vivo. 相似文献
144.
Shimizu Y Temma T Hara I Yamahara R Ozeki E Ono M Saji H 《Journal of fluorescence》2012,22(2):719-727
Optical imaging with near-infrared (NIR) fluorescent probes is a useful diagnostic technology for in vivo tumor detection. Our plan was to develop novel NIR fluorophore-micelle complex probes. IC7-1 and IC7-2 were synthesized as
novel lipophilic NIR fluorophores, which were encapsulated in an amphiphilic polydepsipeptide micelle “lactosome”. The fluorophore-micelle
complexes IC7-1 lactosome and IC7-2 lactosome were evaluated as NIR fluorescent probes for in vivo tumor imaging. IC7-1 and IC7-2 were synthesized and then encapsulated in lactosomes. The optical properties of IC7-1, IC7-2,
IC7-1 lactosome and IC7-2 lactosome were measured. IC7-1 lactosome and IC7-2 lactosome were administered to tumor-bearing
mice, and fluorescence images were acquired for 48 h. IC7-1 and IC7-2 were successfully synthesized in 12% and 6.3% overall
yield, and maximum emission wavelengths in chloroform were observed at 858 nm and 897 nm, respectively. Aqueous buffered solutions
of IC7-1 lactosome and IC7-2 lactosome showed similar fluorescence spectra in chloroform and higher or comparable quantum
yields and higher photostability compared with ICG. Both lactosome probes specifically visualized tumor tissue 6 h post-administration.
IC7-1 lactosome and IC7-2 lactosome could be promising NIR probes for in vivo tumor imaging. 相似文献
145.
Tin ion-exchanged montmorillonite (Sn-Mont) was found to be a powerful heterogeneous catalyst for the cyanosilylation of various ketones including congested ones with a bulky cyanide source, tert-butyldimethylsilyl cyanide (TBDMSCN), giving the corresponding cyanohydrin tert-butyldimethylsilyl ethers in good (85%) to excellent (>98%) yields at room temperature. Compared to the previously reported catalysts, Sn-Mont is easy to prepare, environmentally benign, nontoxic, noncorrosive, and recyclable. 相似文献
146.
147.
148.
Paul K. B. ALANIS Yusuke YAMAYA Akihiro TAKEUCHI Yoichi SASAI Yoshihiro OKADA Toshiyasu NAGAO 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2013,89(8):383-389
Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions. 相似文献
149.
Mikio Hori Tadashi Kataoka Hiroshi Shimizu Sachio Ohno Kenichi Narita Hiroaki Takayanagi Haruo Ogura Yoichi Iitaka 《Tetrahedron letters》1979,20(44):4315-4318
The first success of an X-ray analysis of a thiabenzene derivative, 1-benzoyl-2-methyl-2-thianaphthalene is described. 相似文献
150.
Katsuhiro Saito Yoichi Omura Etsuro Maekawa Paul G. Gassman 《Tetrahedron letters》1984,25(24):2573-2576
Addition reactions of cyclooctatetraene with 1,3-diphenylisobenzofuran resulted in the formation of three 1:1 cycloadducts, 1, 2, and 3, and a 1:2 cycloadduct, 4. Single crystal x-ray analysis established 3 to be a cage compound formed by an unprecedented [4+2] cycloaddition reaction of 1 in which the double bond of the benzene moiety acted as the dienophile. 相似文献