全文获取类型
收费全文 | 4638篇 |
免费 | 112篇 |
国内免费 | 14篇 |
专业分类
化学 | 3517篇 |
晶体学 | 35篇 |
力学 | 74篇 |
数学 | 185篇 |
物理学 | 953篇 |
出版年
2022年 | 33篇 |
2021年 | 44篇 |
2020年 | 50篇 |
2019年 | 56篇 |
2018年 | 39篇 |
2017年 | 41篇 |
2016年 | 76篇 |
2015年 | 86篇 |
2014年 | 88篇 |
2013年 | 214篇 |
2012年 | 205篇 |
2011年 | 219篇 |
2010年 | 116篇 |
2009年 | 122篇 |
2008年 | 223篇 |
2007年 | 219篇 |
2006年 | 240篇 |
2005年 | 253篇 |
2004年 | 248篇 |
2003年 | 196篇 |
2002年 | 227篇 |
2001年 | 137篇 |
2000年 | 112篇 |
1999年 | 79篇 |
1998年 | 57篇 |
1997年 | 44篇 |
1996年 | 66篇 |
1995年 | 63篇 |
1994年 | 72篇 |
1993年 | 60篇 |
1992年 | 86篇 |
1991年 | 65篇 |
1990年 | 57篇 |
1989年 | 51篇 |
1988年 | 45篇 |
1987年 | 38篇 |
1986年 | 53篇 |
1985年 | 75篇 |
1984年 | 64篇 |
1983年 | 27篇 |
1982年 | 53篇 |
1981年 | 34篇 |
1980年 | 33篇 |
1979年 | 49篇 |
1978年 | 39篇 |
1977年 | 45篇 |
1976年 | 31篇 |
1975年 | 30篇 |
1974年 | 32篇 |
1973年 | 38篇 |
排序方式: 共有4764条查询结果,搜索用时 0 毫秒
71.
Koiso T Yamamoto K Hata Y Takahashi Y Kita E Ohshima K Okamura FP 《J Phys Condens Matter》1996,8(38):7059-7065
A structural study of [Formula: see text], grown from aqueous solution, was performed using anomalous x-ray scattering near the Cs K absorption edge to determine an absolute configuration of constituent atoms. The sense of the helical structure of the [Formula: see text] chain was found to be predominantly right-handed through a comparison of observed Bragg Bijvoet ratios with calculated ones. Assuming that [Formula: see text] consists of the two domains (i.e. right- and left-handed helices), we estimate that the volume fraction for the right-handed helix is [Formula: see text]. 相似文献
72.
73.
74.
T. Kato T. Akasaka K. Kobayashi S. Nagase K. Yamamoto H. Funasaka T. Takahashi 《Applied magnetic resonance》1996,11(2):293-300
We observed photochemical and thermal addition of disilirane to the LaC82-A isomer, which give new ESR active species. Both ESR spectra of the adducts in photo- and thermal reactions are well simulated by at least six octet components, and the isotropic La coupling constants and g-factors of the six octet components are determined. On the other hand, the reaction of the LaC82-B isomer with disilirane gives no ESR active species. This fact is also verified by mass spectroscopic measurements. The different reactivities with disilirane of the two isomers are not interpreted by a popular view that the two isomers have a different C82 cage structure, but we rather suggest that the origin of the isomers of metallofullerenes should be re-examined. 相似文献
75.
We derive some rigorous results on the chiral phase transition in QCD and QCD-like theories with a large number of colors, N(c), based on the QCD inequalities and the large-N(c) orbifold equivalence. We show that critical phenomena and associated soft modes are forbidden in flavor-symmetric QCD at finite temperature T and finite but not so large quark chemical potential μ for any nonzero quark mass. In particular, the critical point in QCD at a finite baryon chemical potential μ(B)=N(c)μ is ruled out, if the coordinate (T, μ) is outside the pion condensed phase in the corresponding phase diagram of QCD at a finite isospin chemical potential μ(I)=2μ. 相似文献
76.
77.
78.
Patterson JR Barker A Briere RA Gibbons LK Makoff G Papadimitriou V Somalwar S Wah YW Winstein B Winston R Woods M Yamamoto H Swallow E Bock GJ Coleman R Enagonio J Hsiung YB Stanfield K Stefanski R Yamanaka T Blair G Gollin GD Karlsson M Okamitsu JK Tschirhart R Brisson JC Debu P Peyaud B Turlay R Vallage B 《Physical review letters》1990,64(13):1491-1494
79.
Brick DH Widgoff M Beilliere P Lutz P Narjoux JL Gelfand N Alyea ED Bloomer M Bober J Busza W Cole B Frank TA Fuess TA Grodzins L Hafen ES Haridas P Huang D Huang HZ Hulsizer R Kistiakowsky V Ledoux RJ Milstene C Noguchi S Oh SH Pless IA Steadman S Stoughton TB Suchorebrow V Tether S Trepagnier PC Wadsworth BF Wu Y Yamamoto RK Cohn HO Calligarich E Castoldi C Dolfini R Introzzi G Ratti S Badiak M DiMarco R Jacques PF Kalelkar M Plano RJ Stamer PE Brucker EB Koller EL Alexander G Grunhaus J 《Physical review D: Particles and fields》1990,41(3):765-773
80.
Yoshitaka Ishii Koichi Hirao Takehiko Terao Tsutomu Terauchi Makoto Oba Kozaburo Nishiyama Masatsune Kainosho 《Solid state nuclear magnetic resonance》1998,11(3-4):169-175
A solid state NMR method is presented for determination of a backbone dihedral angle φ in peptides, being based on the previously reported method, relayed anisotropy correlation (RACO) NMR [Y. Ishii et al., Chem. Phys. Lett. 256 (1996) 133]. In the present method, the
and the
dipolar tensors in the
system are two-dimensionally (2D) correlated via polarization transfer from
to
under magic angle spinning (MAS). This method was applied to N-acetyl
,
-valine, and the H–C–N–H dihedral angle was determined to be 154.0±1.4° or 206.0±1.4°, the former agreeing with the X-ray value of 154±5°. 相似文献