全文获取类型
收费全文 | 1784篇 |
免费 | 82篇 |
国内免费 | 6篇 |
专业分类
化学 | 1523篇 |
晶体学 | 24篇 |
力学 | 16篇 |
数学 | 75篇 |
物理学 | 234篇 |
出版年
2022年 | 14篇 |
2021年 | 13篇 |
2020年 | 23篇 |
2019年 | 36篇 |
2018年 | 18篇 |
2017年 | 9篇 |
2016年 | 44篇 |
2015年 | 33篇 |
2014年 | 57篇 |
2013年 | 67篇 |
2012年 | 99篇 |
2011年 | 118篇 |
2010年 | 75篇 |
2009年 | 55篇 |
2008年 | 118篇 |
2007年 | 113篇 |
2006年 | 120篇 |
2005年 | 136篇 |
2004年 | 126篇 |
2003年 | 94篇 |
2002年 | 68篇 |
2001年 | 26篇 |
2000年 | 23篇 |
1999年 | 22篇 |
1998年 | 28篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 17篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1988年 | 13篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 25篇 |
1984年 | 22篇 |
1983年 | 8篇 |
1982年 | 18篇 |
1981年 | 18篇 |
1980年 | 12篇 |
1979年 | 23篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1972年 | 6篇 |
排序方式: 共有1872条查询结果,搜索用时 46 毫秒
1.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
2.
Annals of the Institute of Statistical Mathematics - 相似文献
3.
D3h‐Symmetric Porphyrin‐Based Rigid Macrocyclic Ligands for Multicofacial Multinuclear Complexes in a One‐Nanometer‐Sized Cavity
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yohei Ohkoda Akane Asaishi Tomoya Namiki Tomoaki Hashimoto Midori Yamada Koichiro Shirai Yuta Katagami Dr. Tomoaki Sugaya Prof. Makoto Tadokoro Prof. Akiharu Satake 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11745-11756
The one‐step synthesis of D3h‐symmetric cyclic porphyrin trimers 1 composed of three 2,2′‐[4,4′‐bis(methoxycarbonyl)]bipyridyl moieties and three porphyrinatozinc moieties was achieved from a nickel‐mediated reductive coupling of meso‐5,15‐bis(6‐chloro‐4‐methoxycarbonylpyrid‐2‐yl)porphyrinatozinc. Although cyclic trimers 1 were obtained as a mixture that included other cyclic and acyclic porphyrin oligomers, an extremely specific separation was observed only for cyclic trimers 1 when using columns of silica gel modified with pyrenylethyl, cyanopropyl, and other groups. Structural analysis of cyclic trimers 1 was carried out by means of NMR spectroscopy and X‐ray crystallography. Treatment of an η3‐allylpalladium complex with a cyclic trimer gave a tris(palladium) complex containing three η3‐allylpalladium groups inside the space, which indicated that the bipyridyl moieties inside the ring could work as bidentate metalloligands. 相似文献
4.
Let Cld
AW
(X) be the hyperspace of nonempty closed subsets of a normed linear space X with the Attouch–Wets topology. It is shown that the space Cld
AW
(X) and its various subspaces are AR's. Moreover, if X is an infinite-dimensional Banach space with weight w(X) then Cld
AW
(X) is homeomorphic to a Hilbert space with weight 2
w(X). 相似文献
5.
6.
A multi-layer chip inductor (MCI) was fabricated using polycrystalline Li–Zn–Cu–Mn ferrite and the green-sheet technique, and its complex impedance spectrum was evaluated with the help of numerical calculations. The complex impedance spectra of the MCI component using Ni–Zn–Cu ferrite, which have been widely used for this application, were very sensitive to the residual stress and deviated much from the calculated values; however, it was found that the complex impedance spectrum of the MCI component using Li–Zn–Cu–Mn ferrite is quite well reproduced by calculation, where the complex permittivity and permeability of the polycrystalline ferrite as well as the MCI dimensions, were used. It implied that the magneto-striction effect was negligible in case of MCI using Li–Zn–Cu–Mn ferrite, and that the difference was related to magneto-strictive coefficient of the polycrystalline ferrite. Consequently, utilization of Li–Zn–Cu–Mn ferrite enabled us to easily design the complex impedance of MCI component. 相似文献
7.
Shunsuke Inenaga Ayumi Shinohara Masayuki Takeda Setsuo Arikawa 《Journal of Discrete Algorithms》2004,2(1):33
Suffix trees are a well-known and widely-studied data structure highly useful for string matching. The suffix tree of a string w can be constructed in O(n) time and space, where n denotes the length of w. Larsson achieved an efficient algorithm to maintain suffix trees for a sliding window. It contributes to prediction by partial matching (PPM) style statistical data compression scheme. Compact directed acyclic word graphs (CDAWGs) are a more space-economical data structure for indexing strings. In this paper we propose a linear-time algorithm to maintain CDAWGs for a sliding window. 相似文献
8.
Infrared and nuclear magnetic resonance (NMR) spectroscopies have been applied for quantitative comparison on unsaturated bonds in tetrafluoroethylene (TFE)-propylene (P)-vinylidene fluoride (VdF) terpolymers. These spectroscopies have led to consistent results while they are based on completely different principles. It is shown that the absolute concentration can be evaluated from NMR measurements. The behavior of unsaturation has been discussed in terms of after-treatment such as wet and dry treatments. The result obtained here can give the important information to improve the performance of fluoroelastomer based on TFE-P-VdF terpolymers. 相似文献
9.
Statistical Inference for Stochastic Processes - 相似文献
10.
We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light. 相似文献