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951.
X-ray crystallographic studies of cobalt(III) complexes of 5-methyl-3-formylpyrazole-N(4)-diethylthiosemicarbazone (HMPzNEt2), [Co(MP
z
NEt
2
)
2
]Br·2H
2
O, 5-methyl-3-formylpyrazole-N(4)-dipropylthiosemicarbazone (HMPzNPr
2
), [Co(MP
z
NPr
2
)
2
]Br·2H
2
O and 5-methyl-3formylpyrazole-N(4)-dibutylthiosemicarbazone (HMPzNBu
2
), [Co(MP
z
NBu
2
)
2
]Br·H
2
O, have been reported. In all the three complex species, X-ray crystallography has authenticated a CoN4S2 octahedral coordination with the pair of orthogonally coordinated NNS tridentate ligands in the monodeprotonated form of
the ligand. The two azomethine nitrogen atoms are trans to each other, while the pyrazolyl ring nitrogens and the thiolato sulfurs are in cis positions. A gradual decrease in the dihedral angle between the coordinating ligands has been observed with increase in the
bulkiness of the aliphatic side chains of the substituent on the thiosemicarbazone moieties. In all the three complexes, intraligand
C–H···S contacts appear to arrest the free rotation of the side chains about the C(6)–N(5) single bond.
†Deceased 相似文献
952.
Non-isothermal thermal studies of the dehydration of the double salt hydrates of the type M(I)2SO4·M(II)SO4·6H2O and their D2O analogues were carried out where M(I) = TI(I) and M(II) = Mg(II), Co(II), Ni(II), Cu(II) or Zn(II). Thermal parameters like activation energy, order of reaction, enthalpy change, etc. were evaluated from the analysis of TG, DTA and DTG curves. These thermal parameters were compared with those of other series, like NH4(I), K(I), Rb(I) and Cs(I) studied earlier. On deuteration the nature of dehydration altered in the case of Tl2Zn(SO4)2·6H2O only. The thermal stability of the salt hyd discussed in relation to the salt hydrates of other series. The role of divalent cation on the thermal properties of dehydration of salt hydrates is also discussed. The order of reaction was always found unity. The values of ΔH were within ≈12–≈16 kcal mol?1. 相似文献
953.
Dehydration of double salt hydrates of the type M(I)2SO4·M(II)SO4·6H2O where M(I)Rb(I) and M(II)Mg(II), Mn(II), Co(II), Ni(II), Zn(II) and Cu(II) has been studied by derivatograph. Thermal parameters like activation energy, order of reaction, enthalpy change etc. for each step of dehydration have been evaluated from the analyses of TG, DTA and DTG curves and these parameters are compared with corresponding salt hydrates of the NH4 and K(I) series. These double salt hydrates are deuterated and studied similarly. Activation energies for the first step of dehydration of these salt hydrates increase with the increase of second ionisation potential of the central metal except for Mg. The nature of dehydration changes in the cases of double salt hydrates of Mg(II) and Ni(II) on deuteration. The order of reaction for each case of dehydration has been found to be unity. The enthalpy change per mole of water varies from 11.4 to 17 kcal. 相似文献
954.
From conductometric and thermometric titrations of potassium perrhenate with aqueous hydrofluoric acid the existence of the complex species [ReO4F]2? has been inferred. Attempts to isolate Oxofluororhenates(VII) from aqueous medium under varying conditions have, however, not been successful. 相似文献
955.
M.K. Chaudhuri A. Haas M. Rosenberg M. Velicescu N. Welcman 《Journal of organometallic chemistry》1977,124(1):37-47
Mass spectra of Fe3(CO)9X2 (X S, Se, Te) and Fe2(CO)6X′2 (X′ S, Se) are recorded and their fragmentation pattern given. The thermal decarbonylation has been studied using DTA/TG methods in the temperature range 25–600°C. The results are compared with those obtained from mass-spectroscopic studies. X-ray and magnetic measurements have been carried out on the residues obtained in the decarbonylation process. 相似文献
956.
Sisir K. Saha Ajit K. Chaudhuri 《Journal of polymer science. Part A, Polymer chemistry》1972,10(3):797-808
The effect of various substituted amines on the polymerization of acrylonitrile initiated by ceric ammonium sulfate has been studied in aqueous solution at 30°C. It was found that the secondary and tertiary amines considerably increased the rate of polymerization, whereas the primary amines seemed to have no effect at all. From the kinetic studies it was found that the overall polymerization rate Rp is independent of ceric ion concentration and can be expressed by the equation: Rp = k1 [amine] [monomer] + k2[monomer]2, where k1 and k2 are constants (involving different rate constants). The accelerating effect of the amines was attributed to a redox reaction between the ceric ion and the amine involving a single electron transfer, the relative activity of the different amines being thus dependent on the relative electron-donating tendency of the substituents present in the amine. The mechanism of the polymerization is discussed on the basis of these results, and various kinetic constants are evaluated. 相似文献
957.
Calculations of the ground and excited state potential energy curves of C2 using the third-order effective valence Hamiltonian (Hv3rd) method are benchmarked against full configuration interaction and other correlated single-reference perturbative and nonperturbative theories. The large nonparallelity errors (NPEs) exhibited even by state-of-art coupled cluster calculations through perturbative triples indicate a serious deficiency of these single-reference theories. The Hv method, on the other hand, produces a much reduced NPE, rendering it a viable approximate many-body method for accurately determining global ground and excited state potential energy curvessurfaces. 相似文献
958.
Summary Complexes [NiL3]Br2·H2O (L=2,2-dimethyl-1,3-propanediamine), [NiL2X2] (X=Cl, Br, NCS, CF3CO2, HCCl2CO2 or CCl3CO2 and X2=SO4 or SeO4) and [NiL(HCCl2CO2)2]·H2O have been synthesised and their thermal studies have been investigated in the solid state. The complexes, [NiL2X2] (X=Cl or Br) and NiLX2 (X=Cl or HCCl2CO2) have been isolated thermally in the solid state. All the complexes possess octahedral geometry. [NiL2Br2] and [NiL2(CF3CO2)2] exist in two interconvertible isomeric forms. H for the conversions were determined. [NiL2(HCCl2CO2)2] (5) undergoes an irreversible phase transition (178–188°C; H=4.4kJ mol–1]. NiL(HCCl2CO2)2·H2O shows an exothermic irreversible phase transition (104–128°C; H=–5.8 kJ mol–1) after losing water. The phase transitions are assumed to be due to the conformational changes in the chelate ring of diamine. 相似文献
959.
The synthesis and characterization of ZnLnX2 · mH2O, where L = N2H4; n = 3, 2 and 1.5; X = Cl?, Br? and SO2?4; and m = 0 or 1, have been done and their thermal studies have been carried out using a Shimadzu DT-30 Thermal Analyzer. ZnL3SO4, ZnL2.75SO4, ZnL2SO4, ZnLCl2 and ZnL0.5Cl2 have been synthesized pyrolytically in the solid state from their parent complexes synthesized from solution. Two varieties of ZnL2Cl2 synthesized by us are indistinguishable by IR spectroscopy but possess appreciable differences in their thermal profiles. Two forms of ZnL3SO4 which are also indistinguishable by IR spectroscopy show noticeable differences in their thermal profiles. 相似文献
960.
The reaction of the ligand 2-(2-trifluoromethyl)anilino-4,6-di-tert-butylphenol, H(2)((1)L(IP)), and PdCl(2) (2:1) in the presence of air and excess NEt(3) in CH(2)Cl(2) produced blue-green crystals of diamagnetic [Pd(II)((1)L(ISQ))(2)] (1), where ((1)L(ISQ))(*)(-) represents the o-iminobenzosemiquinonate(1-) pi radical anion of the aromatic ((1)L(IP))(2-) dianion. The diamagnetic complex 1 was chemically oxidized with 1 equiv of Ag(BF(4)), affording red-brown crystals of paramagnetic (S = (1)/(2)) [Pd(II)((1)L(ISQ))((1)L(IBQ))](BF(4)) (2), and one-electron reduction with cobaltocene yielded paramagnetic (S = (1)/(2)) green crystals of [Cp(2)Co][Pd(II)((1)L(ISQ))((1)L(IP))] (3); ((1)L(IBQ))(0) represents the neutral, diamagnetic quinone form. Complex 1 was oxidized with 2 equiv of [NO]BF(4), affording green crystals of diamagnetic [Pd(II)((1)L(IBQ))(2)](3)(BF(4))(4){(BF(4))(2)H}(2).4CH(2)Cl(2) (5). Oxidation of [Ni(II)((1)L(ISQ))(2)] (S = 0) in CH(2)Cl(2) solution with 2 equiv of Ag(ClO(4)) generated crystals of [Ni(II)((1)L(IBQ))(2)(ClO(4))(2)].2CH(2)Cl(2) (6) with an S = 1 ground state. Complexes 1-5 constitute a five-membered complete electron-transfer series, [Pd((1)L)(2)](n) (n = 2-, 1-, 0, 1+, 2+), where only species 4, namely, diamagnetic [Pd(II)((1)L(IP))(2)](2-), has not been isolated; they are interrelated by four reversible one-electron-transfer waves in the cyclic voltammogram. Complexes 1, 2, 3, 5, and 6 have been characterized by X-ray crystallography at 100 K, which establishes that the redox processes are ligand centered. Species 2 and 3 exhibit ligand mixed valency: [Pd(II)((1)L(ISQ))((1)L(IBQ))](+) has localized ((1)L(IBQ))(0) and ((1)L(ISQ))(*)(-) ligands in the solid state, whereas in [Pd(II)((1)L(ISQ))((1)L(IP))](-) the excess electron is delocalized over both ligands in the solid-state structure of 3. Electronic and electron spin resonance spectra are reported, and the electronic structures of all members of this electron-transfer series are established. 相似文献