全文获取类型
收费全文 | 2643篇 |
免费 | 57篇 |
国内免费 | 12篇 |
专业分类
化学 | 2181篇 |
晶体学 | 15篇 |
力学 | 26篇 |
数学 | 110篇 |
物理学 | 380篇 |
出版年
2020年 | 21篇 |
2019年 | 20篇 |
2018年 | 23篇 |
2017年 | 17篇 |
2016年 | 26篇 |
2015年 | 28篇 |
2014年 | 36篇 |
2013年 | 122篇 |
2012年 | 92篇 |
2011年 | 119篇 |
2010年 | 70篇 |
2009年 | 75篇 |
2008年 | 120篇 |
2007年 | 128篇 |
2006年 | 140篇 |
2005年 | 135篇 |
2004年 | 138篇 |
2003年 | 100篇 |
2002年 | 117篇 |
2001年 | 45篇 |
2000年 | 70篇 |
1999年 | 47篇 |
1998年 | 35篇 |
1997年 | 25篇 |
1996年 | 40篇 |
1995年 | 32篇 |
1994年 | 39篇 |
1993年 | 34篇 |
1992年 | 29篇 |
1991年 | 27篇 |
1990年 | 24篇 |
1989年 | 25篇 |
1988年 | 40篇 |
1987年 | 29篇 |
1986年 | 30篇 |
1985年 | 47篇 |
1984年 | 52篇 |
1983年 | 20篇 |
1982年 | 47篇 |
1981年 | 67篇 |
1980年 | 40篇 |
1979年 | 32篇 |
1978年 | 37篇 |
1977年 | 40篇 |
1976年 | 44篇 |
1975年 | 32篇 |
1974年 | 37篇 |
1973年 | 28篇 |
1971年 | 12篇 |
1967年 | 13篇 |
排序方式: 共有2712条查询结果,搜索用时 343 毫秒
1.
Inside Cover: Photoinduced Formation of an Azobenzene‐Based CD‐Active Supramolecular Cyclic Dimer (Chem. Eur. J. 18/2015) 下载免费PDF全文
2.
3.
We study the nonrelativistic limit of the Cauchy problem for the nonlinear Klein-Gordon equation and prove that any finite
energy solution converges to the corresponding solution of the nonlinear Schr?dinger equation in the energy space, after the
infinite oscillation in time is removed. We also derive the optimal rate of convergence in .
Received: 13 July 2000 / Published online: 1 February 2002 相似文献
4.
H. Akimune T. Yamagata S. Nakayama M. Fujiwara K. Fushimi K. Hara K. Y. Hara K. Ichihara K. Kawase K. Matsui K. Nakanishi A. Shiokawa M. Tanaka H. Utsunomiya M. Yosoi 《Physics of Atomic Nuclei》2004,67(9):1721-1725
Trinucleon molecular structures in 6He and 6Be were investigated by using the 6Li(7Li, 7Be)6He reaction at 455 MeV and 6Li(3He, t)6Be reaction at 450 MeV, respectively. Binary decays into t + t from a broad state at E x =18.0±1.0 MeV in 6He and into 3He + 3He from one at E x =18.0±1.2 MeV in 6Be, respectively, were observed by measuring trinucleon cluster decays in coincidence with reaction particles. The branching ratios for binary decay were estimated to be about 0.7 for 6He and 6Be. These large branching ratios show that a trinucleon cluster state exists as an isobaric partner around E x =18 MeV in 6He and 6Be. 相似文献
5.
Yong Lee Kazuhiko Hosomi Hiroyuki Uchiyama Toshio Katsuyama Shinya Kominami Tomoyoshi Mishima 《Optical Review》2003,10(1):38-42
An InGaAsP slab-type asymmetric-coupled-waveguide-based dispersion compensator with a mode selector has been designed and fabricated. The mode selector is necessary to select either a symmetric [with a positive group-velocity dispersion (GVD)] or antisymmetric (with a negative GVD) supermode. These supermodes exist simultaneously in the dispersion-compensation region of the device. Pulse-compression experiments were used to test the dispersion compensator, evaluating the function of the mode selector. A theoretical study of the experimental results shows that the mode selector obtains a very strong selectivity (nearly 100%) for the antisymmetric supermode. 相似文献
6.
Yoshinori Nishiwaki Masahiko Shimoyama Toshio Nakanishi Toshio Ninomiya Izumi Nakai 《Analytical sciences》2006,22(10):1297-1300
Total reflection X-ray fluorescence spectrometry (TXRF) has been applied for trace elemental analysis of small glass fragments. A small glass sample (a fragment with weight less than 0.5 mg) was decomposed by 100 microg of HF/HNO3 acid; the material was condensed to 10 microl and was dried on a Si wafer. Since the size of the dried residue on the Si wafer was less than 1 cm in diameter, an incident X-ray beam with about 1 cm in width could effectively excite elemental components in such a small glass fragment. The precision of the present technique was checked by analyzing the glass fragments (<0.5 mg) from NIST SRM612; the relative standard deviations (RSD) of less than 8.1% were achieved for elemental ratios that were normalized by Sr. Fragments (<0.5 mg) obtained from 23 figured sheet glasses were used as samples for estimating the utility of this technique to forensic discrimination. Comparison of five elemental ratios of Ti/Sr, Mn/Sr, Zn/Sr, Rb/Sr, and Pb/Sr calculated from X-ray fluorescence spectra was effective in distinguishing glass fragments that could not be differentiated by their refractive indexes (RI). 相似文献
7.
Atsuo Kuniba Tomoki Nakanishi Zengo Tsuboi 《Communications in Mathematical Physics》2002,227(1):155-190
We study a class of systems of functional equations closely related to various kinds of integrable statistical and quantum
mechanical models. We call them the finite and infinite $Q$-systems according to the number of functions and equations. The
finite Q-systems appear as the thermal equilibrium conditions (the Sutherland–Wu equation) for certain statistical mechanical systems.
Some infinite Q-systems appear as the relations of the normalized characters of the KR modules of the Yangians and the quantum affine algebras.
We give two types of power series formulae for the unique solution (resp. the unique canonical solution) for a finite (resp.
infinite) Q-system. As an application, we reformulate the Kirillov–Reshetikhin conjecture on the multiplicities formula of the KR modules
in terms of the canonical solutions of Q-systems.
Received: 2 August 2001 / Accepted: 27 December 2001 相似文献
8.
On a certain move generating link-homology 总被引:4,自引:0,他引:4
Dedicated to Professor Kunio Murasugi on his sixtieth birthday 相似文献
9.
Yamada Kaoru Matsutani Shigeaki Uchiyama Akira Takahashi Toshio 《Journal of inclusion phenomena and macrocyclic chemistry》1991,11(1):49-54
Analyses of crown ether complexes of alkali metal ions and characterization of the complexes formed inm-nitrobenzyl alcohol have been carried out by fast atom bombardment (FAB) mass spectrometry. By using m-nitrobenzyl alcohol as a matrix for measurements, the stoichiometry of the complexes was assessed on the basis of the observed FAB peaks. In addition, the formation of crown ether-alkali metal complexes at a 2 : 1 molar ratio was enhanced by increasing the ionic radius of the metal ion in agreement with previous observations. On these grounds, FAB mass spectrometry may provide a rapid means for investigation of the complexation behavior of crown ethers and the stoichiometry of the complexes. 相似文献
10.