全文获取类型
收费全文 | 1389篇 |
免费 | 25篇 |
国内免费 | 13篇 |
专业分类
化学 | 949篇 |
晶体学 | 19篇 |
力学 | 13篇 |
数学 | 118篇 |
物理学 | 328篇 |
出版年
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2017年 | 7篇 |
2016年 | 24篇 |
2015年 | 17篇 |
2014年 | 13篇 |
2013年 | 50篇 |
2012年 | 66篇 |
2011年 | 67篇 |
2010年 | 45篇 |
2009年 | 31篇 |
2008年 | 65篇 |
2007年 | 83篇 |
2006年 | 77篇 |
2005年 | 107篇 |
2004年 | 71篇 |
2003年 | 71篇 |
2002年 | 63篇 |
2001年 | 30篇 |
2000年 | 35篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 15篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 22篇 |
1991年 | 15篇 |
1990年 | 21篇 |
1989年 | 21篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 15篇 |
1985年 | 19篇 |
1984年 | 23篇 |
1983年 | 8篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 16篇 |
1979年 | 22篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 10篇 |
1975年 | 12篇 |
1974年 | 12篇 |
1973年 | 8篇 |
1968年 | 9篇 |
1967年 | 11篇 |
排序方式: 共有1427条查询结果,搜索用时 22 毫秒
101.
Zegers RG Abend H Akimune H van den Berg AM Fujimura H Fujita H Fujita Y Fujiwara M Galès S Hara K Harakeh MN Ishikawa T Kawabata T Kawase K Mibe T Nakanishi K Nakayama S Toyokawa H Uchida M Yamagata T Yamasaki K Yosoi M 《Physical review letters》2003,90(20):202501
The excitation and subsequent proton decay of the isovector spin-flip giant monopole resonance (IVSGMR) is studied via the 208Pb(3He,t) reaction at 410 MeV. In the inclusive spectrum (60+/-5)% of the non-energy-weighted sum-rule strength for this 2 variant Planck's over 2h omega resonance was found in the region 29相似文献
102.
BRST resolution is studied for the principally graded Wakimoto module of
recently found in math.QA/0005203. The submodule structure is completely determined and irreducible representations can be obtained as the zero-th cohomology group. 相似文献
103.
Abe K Abe K Adachi I Ahn BS Aihara H Akatsu M Alimonti G Aoki K Asai K Asai M Asano Y Aso T Aulchenko V Aushev T Bakich AM Banas E Behari S Behera PK Beiline D Bondar A Bozek A Browder TE Casey BC Chang P Chao Y Cheon BG Choi SK Choi Y Doi Y Dragic J Eidelman S Enari Y Enomoto R Everton CW Fang F Fujii H Fujita Y Fukunaga C Fukushima M Garmash A Gordon A Gotow K Guler H Guo R Haba J Haji T Hamasaki H Hanagaki K Handa F Hara K Hara T Hastings NC Hayashi K Hayashii H Hazumi M Heenan EM Higuchi I 《Physical review letters》2001,86(15):3228-3232
We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations. 相似文献
104.
Abe K Abe K Abe R Adachi I Ahn BS Aihara H Akatsu M Alimonti G Asai K Asai M Asano Y Aso T Aulchenko V Aushev T Bakich AM Banas E Behari S Behera PK Beiline D Bondar A Bozek A Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Dong LY Dragic J Drutskoy A Eidelman S Eiges V Enari Y Enomoto R Everton CW Fang F Fujii H Fukunaga C Fukushima M Gabyshev N Garmash A Gershon TJ Gordon A Gotow K Guler H Guo R Haba J Hamasaki H Hanagaki K Handa F Hara K Hara T Hastings NC 《Physical review letters》2001,87(9):091802
We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system. 相似文献
105.
Fujiwara M Akimune H van Den Berg AM Cribier M Daito I Ejiri H Fujimura H Fujita Y Goodman CD Hara K Harakeh MN Ihara F Ishikawa T Janecke J Kawabata T Raghavan RS Schwarz K Tanaka M Yamanaka T Yosoi M Zegers RG 《Physical review letters》2000,85(21):4442-4445
Discrete Gamow-Teller (GT) transitions 176Yb-->176Lu at low excitation energies have been measured via the ( 3He,t) reaction at 450 MeV and at 0 degrees. For 176Yb, two low-lying states are observed, setting low thresholds Q(nu) = 301 and 445 keV for neutrino ( nu) capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(nu) in Yb-Lu indicate that Yb-based nu detectors are well suited for a direct measurement of the sub-MeV solar electron-neutrino ( nu(e)) spectrum including pp neutrinos. 相似文献
106.
Hatakeyama A Oe K Ota K Hara S Arai J Yabuzaki T Young AR 《Physical review letters》2000,84(7):1407-1410
At temperatures below 2.1 K, long-lived gaseous Rb atoms in glass cells have been generated with a simple method: irradiating the cells, containing 4He gas and Rb metal, with a cw laser. The obtained atomic Rb density ( approximately 10(8) cm(-3)) decreases with a 1/e time constant of about 10 s at 1.85 K. We have performed optical pumping of the Rb atoms and measured the longitudinal electronic spin relaxation time at 1.85 K as well. For processes (such as Rb-He collisions) which do not remove the atomic Rb from the vapor, this relaxation time is found to be about 60+/-15 s. 相似文献
107.
108.
Effect of tea polyphenols on glucan synthesis by glucosyltransferase from Streptococcus mutans 总被引:3,自引:0,他引:3
M Hattori I T Kusumoto T Namba T Ishigami Y Hara 《Chemical & pharmaceutical bulletin》1990,38(3):717-720
In the course of our studies on the development of anti-plaque agents for prevention of dental caries, we investigated effects of some of tea preparations and their individual components on the glucan synthesis catalyzed by glucosyltransferase (GTF) from Streptococcus mutans. Extracts of green tea and black tea, and polyphenol mixtures showed appreciable inhibition in the synthesis of insoluble glucan. Among the components isolated from tea infusions, theaflavin and its mono- and digallates had potent inhibitory activities at concentrations of 1-10 mM against GTF. (+)-Catechin, (-)-epicatechin and their enantiomers had moderate inhibitory activities at these concentrations, while galloyl esters of (-)-epicatechin, (-)-epigallocatechin and (-)-gallocatechin had increased inhibitory activities. 相似文献
109.
110.
Hiroaki Miyaoka Yoshinori Hara Ikuo Shinohara Takao Kurokawa Yasuji Yamada 《Tetrahedron letters》2005,46(46):7945-7949
Synthesis of the marine eicosanoid agardhilactone has been achieved. The relative and absolute configuration of agardhilactone was successfully determined. 相似文献