全文获取类型
收费全文 | 811篇 |
免费 | 140篇 |
国内免费 | 106篇 |
专业分类
化学 | 582篇 |
晶体学 | 8篇 |
力学 | 53篇 |
综合类 | 2篇 |
数学 | 77篇 |
物理学 | 335篇 |
出版年
2023年 | 26篇 |
2022年 | 23篇 |
2021年 | 38篇 |
2020年 | 47篇 |
2019年 | 31篇 |
2018年 | 23篇 |
2017年 | 17篇 |
2016年 | 47篇 |
2015年 | 46篇 |
2014年 | 31篇 |
2013年 | 58篇 |
2012年 | 69篇 |
2011年 | 89篇 |
2010年 | 57篇 |
2009年 | 63篇 |
2008年 | 56篇 |
2007年 | 42篇 |
2006年 | 49篇 |
2005年 | 33篇 |
2004年 | 17篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 14篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 15篇 |
1994年 | 6篇 |
1993年 | 17篇 |
1992年 | 13篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有1057条查询结果,搜索用时 15 毫秒
111.
112.
Laser-induced Fluorescence Spectroscopy of NiS: Identification of a Low-lying Electronic State 下载免费PDF全文
Laser-induced fluorescence excitation spectra of jet-cooled NiS molecules were recorded in the energy range of 12200-13550 cm-1. Four vibronic bands with rotational structure have been observed and assigned to the [12.4]3∑0- -X3∑0- transition progression. The relevant rotational constants, significant isotopic shifts, and (equilibrium) molecular parameters have been determined. In addition, the lifetimes of the observed bands have also been measured. 相似文献
113.
关于绝对半素环和绝对半素根 总被引:3,自引:0,他引:3
张宪君 《纯粹数学与应用数学》1993,9(2):57-60
本文了绝对半素环的概念,研究了绝对半素与与半素环及素环之间的关系,讨论了由全体绝对半素环类决定的上根--绝对半半素根及其性质。 相似文献
114.
Jinxia Xu Yueyan Zang Fanyong Yan Jingru Sun Yuyang Zhang Chunhui Yi 《Particle & Particle Systems Characterization》2021,38(11):2100201
Carbon dots (CDs) are emerging photoluminescent materials with excellent optical properties. However, the lack of active sites in primitive CDs has limited their development applications. Herein, functionalized carbon dots (Z-CDs) are successfully prepared by surface modification of CDs with mono (6-amino-6-deoxy) cyclodextrin (β-CD). The introduction of β-CD increases the spatial potential resistance between CDs, which effectively reduces the self-quenching effect. Moreover, the conjugated domains of Z-CDs are expanded, which improves the optical properties with a quantum yield of 48.74%. Z-CDs are able to be used in the sequential detection of morin and Al3+, and the fluorescence mechanisms are confirmed to be internal filtration effect and fluorescence resonance energy transfer, respectively. The limits of detection are 0.817 and 0.231 × 10−6 m . This study not only provides an idea to solve the problem of self-quenching of CDs but also enriches the detection means of flavonoids and ions, which is expected to be applied to biosensing and environmental monitoring. 相似文献
115.
Hong Y Liao JY Cao D Zang X Kuang DB Wang L Meier H Su CY 《The Journal of organic chemistry》2011,76(19):8015-8021
A novel efficient metal free sensitizer containing asymmetric double donor-π-acceptor chains (DC) was synthesized for dye-sensitized solar cells (DSSCs). Comparing to 3.80%, 4.40% and 4.64% for the DSSCs based on the dyes with single chain (SC1, SC2) and cosensitizers (SC1 + SC2), the overall conversion efficiency reaches 6.06% for DC-sensitized solar cells as a result of its longer electron lifetime and higher incident monochromatic photon-to-current conversion efficiency. 相似文献
116.
Li Zhang Xin‐An Chang Xue‐An Chen He‐Gui Zang Wei‐Qiang Xiao 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):i76-i78
The title compound represents a new structure type, in which distorted VO6 octahedra are bridged by iodate groups to form infinite two‐dimensional [VO2(IO3)2]− layers that are separated by octahedrally coordinated Li+ cations. 相似文献
117.
Towards Fabrication of Atomic Dopant Wires via Monolayer Doping Patterned by Resist-Free Lithography 下载免费PDF全文
Fabrication of atomic dopant wires at large scale is challenging.We explored the feasibility to fabricate atomic dopant wires by nano-patterning self-assembled dopant carrying molecular monolayers via a resist-free lithographic approach.The resist-free lithography is to use electron beam exposure to decompose hydrocarbon contaminants in vacuum chamber into amorphous carbon that serves as an etching mask for nanopatterning the phosphorus-bearing monolayers.Dopant wires were fabricated in silicon by patterning diethyl vinylphosphonate monolayers into lines with a width ranging from 1 μm down to 8 nm.The dopants were subsequently driven into silicon to form dopant wires by rapid thermal annealing.Electrical measurements show a linear correlation between wire width and conductance,indicating the success of the monolayer patterning process at nanoscale.The dopant wires can be potentially scaled down to atomic scale if the dopant thermal diffusion can be mitigated. 相似文献
118.
119.
研究了液体冷媒融霜系统应用于小型冷库制冷系统的性能;介绍了液体冷媒融霜原理和控制操作过程、液体冷媒融霜实验的装置和方法;对实验结果进行了分析;重点通过库温变化、蒸发器进出口温度压力变化、过冷度对系统的影响、系统COP几个方面,研究了液体冷媒融霜应用于小型冷库制冷系统的性能。 相似文献
120.