全文获取类型
收费全文 | 2797篇 |
免费 | 44篇 |
国内免费 | 8篇 |
专业分类
化学 | 1875篇 |
晶体学 | 24篇 |
力学 | 41篇 |
综合类 | 1篇 |
数学 | 119篇 |
物理学 | 789篇 |
出版年
2022年 | 14篇 |
2021年 | 19篇 |
2020年 | 29篇 |
2019年 | 32篇 |
2018年 | 23篇 |
2017年 | 23篇 |
2016年 | 43篇 |
2015年 | 38篇 |
2014年 | 45篇 |
2013年 | 127篇 |
2012年 | 109篇 |
2011年 | 152篇 |
2010年 | 72篇 |
2009年 | 79篇 |
2008年 | 157篇 |
2007年 | 197篇 |
2006年 | 169篇 |
2005年 | 178篇 |
2004年 | 159篇 |
2003年 | 135篇 |
2002年 | 129篇 |
2001年 | 66篇 |
2000年 | 62篇 |
1999年 | 44篇 |
1998年 | 40篇 |
1997年 | 38篇 |
1996年 | 42篇 |
1995年 | 46篇 |
1994年 | 38篇 |
1993年 | 42篇 |
1992年 | 52篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 28篇 |
1988年 | 21篇 |
1987年 | 33篇 |
1986年 | 19篇 |
1985年 | 29篇 |
1984年 | 30篇 |
1983年 | 14篇 |
1982年 | 26篇 |
1981年 | 26篇 |
1980年 | 27篇 |
1979年 | 29篇 |
1978年 | 20篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1974年 | 13篇 |
1973年 | 15篇 |
排序方式: 共有2849条查询结果,搜索用时 9 毫秒
21.
Abstract Color centers in rutile-structured MgF2 single crystals irradiated at 20K/360K by reactor neutrons are investigated spectroscopically at LNT. Four different types of the F-F vacancy bond in MgF2 are possibly identified to the observed absorption bands as due to the F2 centers; instead of previous assignments, the 300nm band to the F2(D2h), the 325nm band to the F2(C1), the 355nm band to the F2(C2v), and the 400nm band to the F2(C2h) centers. 相似文献
22.
Satoru Nakashima Yuichi Masuda Izumi Motoyama Hirotoshi Sano 《Hyperfine Interactions》1988,40(1-4):319-322
It was found that the packing of cations and anions influences the electronic structures of mixed-valence binuclear ferrocene derivatives. Temperature-dependence of the mixed-valence state of 11, 1111-diisobutylbiferrocenium triiodide was observed in a crystalline state, whereas only a trapped-valence state was found in a dispersed state. The packing effect was also observed for a series of 11, 1111-dialkyl- and 11, 1111-bis(methylbenzyl)biferrocenium triiodides by means of ESR spectroscopy. 相似文献
23.
Adachi I Aihara H Dijkstra HB Enomoto R Fujii H Fujii K Fujii T Fujimoto J Fujiwara N Hayashii H Higashi S Iida N Imanishi A Ikeda H Ishii T Itoh R Iwasaki H Iwata S Kajikawa R Kamae T Kato S Kawabata S Kichimi H Kishida T Kobayashi M Kuroda S Kusuki N Maruyama A Maruyama K Masuda H Matsuda T Miyamoto A Morimoto T Nakamura K Nitoh O Noguchi S Ochiai F Okuno H Okusawa T Ohshima T Ozaki H Sato T Sai F Shimonaka J Shimozawa K Shirahashi A Sugahara R Sugiyama A Suzuki S Suwada T Takahashi K 《Physical review letters》1988,60(2):97-100
24.
25.
The luminescence induced by heavy charged particle irradiation has been measured. The bi-exciton lines (MT and ML) and the line at 3926 Å were observed. It is concluded that these lines arise from the densely excited region in particle tracks. 相似文献
26.
Yoshiro Fukuoka Tatsuo Itoh 《International Journal of Infrared and Millimeter Waves》1984,5(6):793-801
A Schottky contact variable phase shifter constructed on either uniformly or periodically doped GaAs substrate is discussed in details. The device can operate at millimeter-wave frequencies with reasonably low attenuation.Work supported by the Office of Naval Research under Contract N00014-79-0053, Joint Service Electronics Program under Grant F49620-82-C-0033, and US Army Research Office under Contract DAAG29-81-K-0053. 相似文献
27.
Itoh T 《Journal of fluorescence》2006,16(6):739-742
Effects of the reflection mirrors mounted to the sample holder of a fluorimeter have been investigated. Analytical expressions
are given for the emission intensity measured as a function of the concentration or optical density of the sample, in case
one or two reflection mirrors are attached beside the sample holder to intensify the emission signals. The emission intensity
calculated as a function of the sample concentration agreed well with the experimental data. By mounting two reflection mirrors,
the emission signal was intensified by a factor of near 3.5. However, the degree of intensification depended strongly on the
sample concentration and the linearity between the sample concentration and the emission intensity deviated significantly
with increasing the sample concentration. 相似文献
28.
Some aspects concerning the subfringe integration method in interferogram analysis have been investigated and modified. The modified algorithm, introduced in this paper, is capable of reconstructing the phase in the presence of noise or errors in carrier frequency. The subfringe integration method was applied to analyze two computer simulated patterns of equispaced Fizeau fringes using N bucket integration. Also, it is used to analyze the multiple-beam Fizeau fringe. The refractive index profile of polyethylene fiber is obtained by using two methods, subfringe integration method, and Fourier transform method. A comparison between the obtained results using the maintained methods is presented. 相似文献
29.
Fang F Hojo T Abe K Abe K Abe T Adachi I Aihara H Akatsu M Asano Y Aso T Aulchenko V Bakich AM Ban Y Banas E Bay A Behera PK Bizjak I Bondar A Bozek A Bracko M Brodzicka J Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Choi YK Danilov M Drutskoy A Eidelman S Eiges V Enari Y Fukunaga C Gabyshev N Garmash A Gershon T Golob B Hara T Hastings NC Hayashii H Hazumi M Heenan EM Higuchi T Hinz L Hokuue T Hoshi Y Hou WS Huang HC Igaki T Igarashi Y Iijima T Inami K 《Physical review letters》2003,90(7):071801
We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(0)(S)K+/-pi(-/+), K+K-pi(0), K(*0)K-pi(+), and pp; decay channels. The neutral B0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin(2phi(1). We also report the first observation of the B0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB. 相似文献
30.
Sekiguchi K Sakai H Witała H Glöckle W Golak J Hatanaka K Hatano M Itoh K Kamada H Kuboki H Maeda Y Nogga A Okamura H Saito T Sakamoto N Sakemi Y Sasano M Shimizu Y Suda K Tamii A Uesaka T Wakasa T Yako K 《Physical review letters》2005,95(16):162301
Three precise measurements for elastic pd scattering at 135 MeV/A have been performed with the three different experimental setups. The cross sections are described well by the theoretical predictions based on modern nucleon-nucleon forces combined with three-nucleon forces. Relativistic Faddeev calculations show that relativistic effects are restricted to backward angles. This result supports the two measurements recently reported by RIKEN and contradicts the KVI data. 相似文献