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991.
The oxidations of cis- and trans-[OsIII(tpy)(Cl)2(NH3)](PF6), cis-[OsII(bpy)2(Cl)(NH3)](PF6), and [OsII(typ)(bpy)(NH3)](PF6)2 have been studied by cyclic voltammetry and by controlled-potential electrolysis. In acetonitrile or in acidic, aqueous solution, oxidation is metal-based and reversible, but as the pH is increased, oxidation and proton loss from coordinated ammonia occurs. cis- and trans-[OsIII(tpy)(Cl)2(NH3)](PF6) are oxidized by four electrons to give the corresponding OsVI nitrido complexes, [OSVI(typ)(Cl)2(N)]+. Oxidation of [Os(typ)(bpy)(NH3)](PF6)2 occurs by six electrons to give [Os(tpy)(bpy)(NO)](PF6)3. Oxidation of cis-[OsII(bpy)2(Cl)(NH3)](PF6) at pH 9.0 gives cis-[OsII(bpy)2(Cl)(NO)](PF6)2 and the mixed-valence form of the mu-N2 dimer [cis-[Os(bpy)2(Cl)2[mu-N2)](PF6)3. With NH4+ added to the electrolyte, cis-[OsII(bpy)2(Cl)(N2)](PF6) is a coproduct. The results of pH-dependent cyclic voltammetry measurements suggest OsIV as a common intermediate in the oxidation of coordinated ammonia. For cis- and trans-[OsIII(tpy)(Cl)2(NH3)]+, OsIV is a discernible intermediate. It undergoes further pH-dependent oxidation to [OsVI(tpy)(Cl)2(N)]+. For [OsII(tpy)(bpy)(NH3)]2+, oxidation to OsIV is followed by hydration at the nitrogen atom and further oxidation to nitrosyl. For cis-[OsII(bpy)2(Cl)-(NH3)]+, oxidation to OsIV is followed by N-N coupling and further oxidation to [cis-[Os(bpy)2(Cl)2(mu-N2)]3+. At pH 9, N-N coupling is competitive with capture of OsIV by OH- and further oxidation, yielding cis-[OsII(bpy)2(Cl)(NO)]2+. 相似文献
992.
Fry HC Hoertz PG Wasser IM Karlin KD Meyer GJ 《Journal of the American Chemical Society》2004,126(51):16712-16713
Single wavelength excitation (lambdaex = 355 or 532 nm) of low-temperature stabilized (198 K) synthetic heme-dioxygen and heme-dioxygen/M complexes, where M = copper or iron in a non-heme environment, results in the dissociation of dioxygen as indicated by the generation of the ferrous heme (Soret band, 427 nm) and the bleaching of the ferric-superoxide (FeIII(O2-)) 410-nm Soret band in the transient absorption difference spectrum. Dioxygen rebinds to the four heme complexes studied with comparable rate constants ( approximately 6-9 x 105 M-1 s-1). However, the quantum yield for complete dissociation of O2 from our simplest heme-O2 complex (F8)FeIII(O2-) (phi = 0.60) is higher than the other complexes measured (phi = approximately 0.2-0.3) as well as that for oxy-myoglobin (phi = 0.3). 相似文献
993.
J. Hladký M. Novák A. Prokeš J. Votruba V. I. Genchev V. D. Kekelidze V. G. Krivokhizhin V. V. Kukhtin M. F. Likhachev I. Manno I. A. Savin L. V. Silvestrov G. Vesztergombi K. -F. Albrecht A. Meyer H. -E. Ryseck M. Sachwitz F. Deak 《Czechoslovak Journal of Physics》1976,26(11):1290-1293
New experimental results on the coherentK
L
0
C K
S
0
C regeneration in the momentum range 10p30 GeV/c are presented. For the quantity (f
0–¯f
0/k (where f0 and¯f
0 are theKC and¯K
0C forward scattering amplitudes andk is the wave number) we have obtained: arg (f
0–¯f
0)/k=–126±14 and ¦(f
0–¯f
0/k¦ p
–0.62±0.14 These results are well described by a simple Regge pole model including only the (-trajectory exchange in thet-channel with the intercept (0) close to 0.4.Presented at the IV International Symposium on High Energy and Elementary Particle Physics, Warszaw, September 1975. 相似文献
994.
995.
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997.
Berger C Fröhlich M Mönch H Nisius R Raupach F Schleper P Benadjal Y Blum D Bourdarios C Dudelzak B Eschstruth P Jullian S Lalanne D Laplanche F Longuemare C Paulot C Perdereau O Roy P Szklarz G Behr L Degrange B Minet Y Nguyen-Khac U Serri P Tisserant S Tripp RD Arpesella C Bareyre P Barloutaud R Borg A Chardin G Ernwein J Glicenstein JF Mosca L Moscoso L Becker J Becker KH Daum HJ Demski S Jacobi B Kuznik B Mayer R Meyer H Möller R Schubnell M Seyffert B Wei Y Wintgen P 《Physical review D: Particles and fields》1989,40(7):2163-2171
998.
999.
Jung C Abachi S Akerlof C Baringer P Beltrami I Blockus D Bonvicini G Brabson B Brom JM Bylsma BG Chapman J Cork B DeBonte R Derrick M Errede D Gan KK Gray SW Guillaud J Harnew N Kesten P Koltick D Kooijman P Loeffler FJ Loos JS Low EH McIlwain RL Meyer DI Miller DH Musgrave B Neal H Ng CR Nitz D Ogren H Price LE Rangan LK Repond J Rust DR Schlereth J Shibata EI Sugano K Thun R Trinko T Valdata-Nappi M Weiss JM Willutzky M Wood DE 《Physical review letters》1986,56(17):1775-1778
1000.
Baringer P Abachi S Akerlof C Beltrami I Blockus D Bonvicini G Brabson B Brom JM Bylsma BG Chapman J Cork B DeBonte R Derrick M Daigo M Errede D Gan KK Gray SW Guillaud J Harnew N Jung C Kesten P Koltick D Kooijman P Loeffler FJ Loos JS Low EH McIlwain RL Meyer DI Miller DH Musgrave B Neal H Nitz D Ng CR Ogren H Price LE Rangan LK Rust DR Schlereth J Seidl AA Shibata EI Sugano K Thun R Trinko T Valdata-Nappi M Weiss JM Willutzky M Wood DE 《Physical review letters》1986,56(13):1346-1349