全文获取类型
收费全文 | 925篇 |
免费 | 27篇 |
国内免费 | 7篇 |
专业分类
化学 | 652篇 |
晶体学 | 13篇 |
力学 | 21篇 |
数学 | 42篇 |
物理学 | 231篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 11篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 19篇 |
2014年 | 23篇 |
2013年 | 34篇 |
2012年 | 28篇 |
2011年 | 53篇 |
2010年 | 25篇 |
2009年 | 27篇 |
2008年 | 52篇 |
2007年 | 71篇 |
2006年 | 56篇 |
2005年 | 79篇 |
2004年 | 86篇 |
2003年 | 41篇 |
2002年 | 60篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 14篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 4篇 |
1978年 | 11篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1973年 | 5篇 |
1969年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有959条查询结果,搜索用时 15 毫秒
911.
Abe K Abe K Abe N Abe T Adachi I Aihara H Akai K Akatsu M Akemoto M Asano Y Aso T Aulchenko V Aushev T Bakich AM Ban Y Banerjee S Bay A Bedny I Bizjak I Bondar A Bozek A Bracko M Browder TE Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Chuvikov A Cole S Danilov M Dragic J Drutskoy A Eidelman S Eiges V Enari Y Epifanov D Flanagan J Furukawa K Gabyshev N Garmash A Gershon T Golob B Haba J Hara K Hastings NC Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hou WS Hsiung YB Huang HC Iijima T Ikeda H 《Physical review letters》2004,93(2):021601
We report the first observation of CP violation in B0-->pi(+)pi(-) decays based on 152x10(6) gamma (4S)-->BB decays collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A(pipi)=+0.58+/-0.15(stat)+/-0.07(syst) and S(pipi)=-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, A(pipi)=S(pipi)=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S(pipi) value. 相似文献
912.
Chistov R Abe K Abe K Abe T Aihara H Akatsu M Asano Y Aushev T Bakich AM Ban Y Banerjee S Bay A Bedny I Bizjak I Bondar A Bozek A Bracko M Brodzicka J Browder TE Chao Y Chen KF Cheon BG Choi Y Choi YK Danilov M Dash M Dong LY Drutskoy A Eidelman S Eiges V Epifanov D Gabyshev N Garmash A Gershon T Golob B Guo R Haba J Hara T Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hou WS Huang HC Iijima T Inami K Ishikawa A Iwasaki H Iwasaki M Kagan R Kang JH Kang JS Kapusta P Katayama N Kawai H Kawasaki T 《Physical review letters》2004,93(5):051803
We report the first observation of the decay B+-->psi(3770)K+ where the psi(3770) is reconstructed in the D0(-)D(0) and D+D- decay channels. The obtained branching fraction is B(B+-->psi(3770)K+)=(0.48+/-0.11+/-0.07)x10(-3). We have measured the branching fraction for the decay B+-->D0(-)D0K+ to be (1.17+/-0.21+/-0.15)x10(-3) and set a 90% confidence level upper limit of 0.90 x 10(-3) for the decay B+-->D+D-K+. We also present the results of a search for possible decays to D(-)D and D0(-)D(0)pi(0) of the recently observed X(3872) particle. The analysis is based on 88 fb(-1) of data collected at the Upsilon(4S) resonance by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. 相似文献
913.
A versatile method for stereoselective formation of multisubstituted bicyclo[4.2.0]octane framework has been developed by means of catalytic (4 + 2)-(2 + 2) cycloaddition reactions. Its application to the synthesis of a substance reported to be the cytotoxic sesquiterpene, paesslerin A, is described, and it has been made clear that a revision of the structure of natural paesslerin A is required. 相似文献
914.
Tanaka O Kanematsu M Kondo H Goshima S Nishibori H Kato H Kiryu T Yokoyama R Hoshi H Moriyama N 《Magnetic resonance imaging》2005,23(1):111-114
A 65-year-old man with multiple hepatocellular carcinomas in the liver with type C viral hepatitis had a solitary mediastinal lymph node metastasis in the right paratracheal to tracheobronchial region. Surgical resection for the mediastinal metastasis was undertaken based on magnetic resonance (MR) imaging findings, suggesting its radicality. We assess the MR imaging findings and presumable pathways of lymphatic metastasis from the liver to mediastinal lymph nodes in this report. 相似文献
915.
Chen KF Abe K Abe K Aihara H Asano Y Aulchenko V Aushev T Bahinipati S Bakich AM Bedny I Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang MC Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Choi SK Choi Y Chuvikov A Dalseno J Danilov M Dash M Drutskoy A Eidelman S Enari Y Fang F Fratina S Gabyshev N Garmash A Gershon T Gokhroo G Golob B Gorisek A Haba J Hastings NC Hayasaka K Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hou S Hou WS Hsiung YB Iijima T Imoto A 《Physical review letters》2005,94(22):221804
We present measurements of decay amplitudes and triple-product correlations in B-->phiK* decays based on 253 fb(-1) of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. The decay amplitudes for the three different helicity states are determined from the angular distributions of final-state particles. The longitudinal polarization amplitudes are found to be 0.45 +/- 0.05 +/- 0.02 for B0-->phiK(*0) and 0.52 +/- 0.08 +/- 0.03 for B+ -->phiK(*+) decays. CP- and T-odd CP-violating triple-product asymmetries are measured to be consistent with zero. 相似文献
916.
Yang H Nakao M Abe K Abe K Aihara H Asano Y Aushev T Bahinipati S Bakich AM Ban Y Bedny I Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang MC Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Choi SK Choi Y Choi YK Chuvikov A Cole S Dalseno J Dash M Eidelman S Enari Y Fang F Gabyshev N Garmash A Gershon T Gokhroo G Golob B Haba J Hayasaka K Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hsiung YB Iijima T Imoto A Inami K Iwasaki Y Kang JH Kang JS Kataoka SU 《Physical review letters》2005,94(11):111802
We report the observation of the radiative decay B+-->K1(1270)(+) gamma using a data sample of 140 fb(-1) taken at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- collider. We find the branching fraction to be B(B+-->K1(1270)(+)gamma)=(4.3+/-0.9(stat.)+/-0.9(syst.))x10(-5) with a significance of 7.3sigma. We find no significant signal for B+-->K1(1400)(+)gamma and set an upper limit B(B+-->K1(1400)(+)gamma)<1.5 x 10(-5) at the 90% confidence level. We also measure inclusive branching fractions for B+-->K+pi+pi-gamma and B0-->K0pi+pi-gamma in the mass range 1 GeV/c(2)相似文献
917.
We report that stimulated Brillouin scattering (SBS) in a dispersion-decreasing fiber (DDF) is particularly disadvantageous with ultrahigh-speed femtosecond soliton compression that exceeds 40 GHz. It is important to note that the increase in the longitudinal mode power of a soliton is proportional to the square of the repetition rate. The SBS threshold is determined by the dispersion-decreasing rate of the DDF, rather than its fiber loss. We suppressed the SBS by applying 30-MHz frequency modulation to a mode-locked fiber laser and successfully obtained a stable 40-GHz, 100-fs pulse train. 相似文献
918.
Tetrahydrofurans were synthesised via 5-exo-trig cyclisation of alkoxy radical generated by unprecedented 1,5-hydrogen shift from hydroxyl group to vinyl radical. 相似文献
919.
Chen KF Bozek A Abe K Abe K Abe T Adachi I Aihara H Akatsu M Asano Y Aso T Bakich AM Ban Y Banas E Bay A Behera PK Bizjak I Bondar A Bracko M Brodzicka J Browder TE Casey BC Chang MC Chang P Chao Y Cheon BG Chistov R Choi SK Choi Y Choi YK Danilov M Dash M Dong LY Drutskoy A Eidelman S Eiges V Enari Y Fukunaga C Gabyshev N Garmash A Gershon T Golob B Guo R Haba J Hagner C Handa F Hayashii H Hazumi M Higuchi T Hinz L Hokuue T Hoshi Y Hou WS Hsiung YB Huang HC Igarashi Y Iijima T Inami K 《Physical review letters》2003,91(20):201801
We present the first measurement of decay amplitudes in B-->phiK* and measurements of branching fractions in B-->phiK(*) decays based on 78.1 fb(-1) of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring. The decay amplitudes for the different phiK*0 helicity states are measured from the angular distributions of final state particles in the transversity basis. The longitudinal and transverse complex amplitudes are |A0|2=0.43+/-0.09+/-0.04, |A(perpendicular)|2=0.41+/-0.10+/-0.04, arg((A(parallel))=-2.57+/-0.39+/-0.09, and arg((A(perpendicular))=0.48+/-0.32+/-0.06. The direct CP-violating asymmetries are found to be consistent with zero. 相似文献
920.
Kaneko J Abe K Abe K Abe T Adachi I Ahn BS Aihara H Akatsu M Asano Y Aso T Aulchenko V Aushev T Bakich AM Ban Y Banas E Bartel W Bay A Behera PK Bondar A Bozek A Bracko M Brodzicka J Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi Y Choi YK Danilov M Dong LY Eidelman S Eiges V Enari Y Everton CW Fang F Fujii H Fukunaga C Gabyshev N Garmash A Gershon T Guo R Haba J Handa F Hara T Harada Y Hastings NC Hayashii H Hazumi M Heenan EM Higuchi I Higuchi T Hinz L Hojo T Hoshi Y 《Physical review letters》2003,90(2):021801
We report the first measurement of the branching fraction for the inclusive decay B-->X(s)l(+)l(-), where l is either an electron or a muon, and X(s) is a hadronic recoil system that contains an s quark. We analyzed a data sample of 65.4 x 10(6) B meson pairs collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. We find B(B-->X(s)l(+)l(-))=[6.1 +/-1.4(stat) +1.4-1.1(syst)] x 10(-6) for dilepton masses greater than 0.2 GeV/c(2). 相似文献