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21.
Surendra K Krishnaveni NS Reddy MA Nageswar YV Rao KR 《The Journal of organic chemistry》2003,68(5):2058-2059
A mild and efficient oxidation of alcohols with o-iodoxybenzoic acid (IBX) catalyzed by beta-cyclodextrin in a water/acetone mixture (86:14) has been developed. A series of alcohols were oxidized at room temperature in excellent yields. 相似文献
22.
The o-, m-, and p-phenylene bis(1,3-dioxolanium) dications (4-6) and 2,4,6-triphenylene tris(1,3-dioxolanium) trication (7) have been prepared by the ionization of the corresponding 2-methoxyethyl benzoates in FSO(3)H or CF(3)SO(3)H at 40 and 60 degrees C, respectively. The charge delocalization in these carbocations was probed by (13)C NMR chemical shifts and substantiated by GIAO/DFT calculations. Relatively less charge is delocalized into the aromatic ring of the carbotrication 7. The rotational barrier around the C(+)-Ar bond for carbodications 4 and 5 was also estimated to be 8-10 kcal/mol. 相似文献
23.
An efficient and mild method for the reduction of aromatic nitro and azido groups on solid support using Al/NiCl2·6H2O and Al/NH4Cl is described. This solid phase reduction technique has been applied towards the synthesis of DNA binding pyrrolo[2,1-c][1,4]benzodiazepine antitumour antibiotics. 相似文献
24.
Venkatapuram Padmavathi Mudigonda Rajagopala Sarma Adivireddy Padmaja Dandu Bhaskar Reddy 《Journal of heterocyclic chemistry》2003,40(5):933-937
Novel 2‐pyrazolines were obtained by the cycloaddition of diazomethane to bis(arylsulfonylethenyl)‐sulfones ( 3 ) and 1‐arylsulfonyl‐2‐styrylsulfonylethenes (7). Dehydrogenation of 2‐pyrazolines with chloranil gave pyrazoles. 相似文献
25.
Ruthenium halides (Cl and Br) react with monotertiary arsines-Ph2RAs (R=Me, Et, Pr
n
) in methoxyethanol, in the presence of aq. formaldehyde to give monocarbonyl complexes of ruthenium(II) of the type RuX2(CO) (Ph2RAs)3. Carbonylation of an ethanolic solution containing ruthenium trichloride and the arsine at room temperature yieldtrans dicarbonyl compounds of the formula RuCl2(CO)2 (Ph2RAs)2. The osmium monocarbonyls OsX2(CO) (Ph2RAs)3 (X=Cl, Br; R=Me, Et) react with NaBH4 in methanol to yield complexes of the composition OsHX(CO) (Ph2RAs)3. The ruthenium analogues RuHCl(CO) (Ph2RAs)3 have also been made. Structures have been assigned to all these compounds on the basis of IR and NMR spectral results. 相似文献
26.
The polymerization of acrylonitrile (AN) initiated by oxygen-ascorbic acid (AA)-ferric ion system was studied in dil. HNO3 at 40°. The rate of polymerization, Rp, was found gravimetrically. In the [Fe3+] range, (2–5 × 10?5 M, Rp was proportional to [AN]1.5 ± 0.05, [O2]0.5 ± 0.02 [AA]0 and [Fe3+]0; for [Fe3+] = (5–30) × 10?5 M, it was proportional to [AN]1.8 ± 0.05, [O2]0.6 ± 0.02, [AA]0 and [Fe3+]?0.9 ± 0.05. A plausible reaction scheme is proposed and rate law presented to explain these results. Rp increased with ionic strength and [HNO3] (up to ~0.25 M). An initial rate increase with temperature followed by a decrease was noticed. Chain lengths of the polymers were determined viscometrically. 相似文献
27.
A. V. Reddy M. L. P. Reddy Y. K. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》1984,86(6):391-397
The extraction of cobalt/II/ from ammonium chloride-ammonium hydroxide buffer solutions of pH 6.5 by 2,4-dihydroxyacetophenone thiosemicarbazone /DATS/ in n-butanol has been studied. Cobalt/II/ forms 11 complex /metal:reagent/ with DATS. Addition of pyridine enhances the extraction. The influence of metal concentration and the effect of diverse ions on the extraction of cobalt/II/ have been investigated. 相似文献
28.
Rajuru R. Reddy Agarala S. R. Reddy Vanka Krishna Reddy 《Theoretical chemistry accounts》1985,67(3):187-191
The bond dissociation energies for Alkali halides have been estimated based on the derived relations: $$\begin{gathered} D_{AB} = \bar D_{AB} + 31.973{\text{ e}}^{0.363\Delta x} {\text{ and}} \hfill \\ D_{AB} = \bar D_{AB} (1 - 0.2075\Delta xr_e ) + 52.29\Delta x, \hfill \\ \end{gathered} $$ where \(\bar D_{AB} = (D_{AA} \cdot D_{BB} )^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-0em} 2}} \) , Δx represents Pauling electronegativity differences x(A ?xB) and r e is the internuclear distance. A simplified formula relating bond orders, q, to spectroscopic constants is suggested. The formula has the form q = 1.5783 × 10?3 (ω e 2 re/ Be)1/2. The ambiguity arising from the Parr and Borkman relation is discussed. The present study supports the view of Politzer that q/(0.5r e)2 is the correct definition of bond order. The estimated bond energies and bond orders are in reasonably good agreement with the literature values. The bond energies estimated with the relations we suggested, for alkali halides give an error of 4.5% and 5.3%, respectively. The corresponding error associated with Pauling's equation is 40.2%. 相似文献
29.
A simple liquid chromatographic method was developed for the separation and quantification of voriconazole and its enantiomer
in drug substance. The separation was achieved on Chiral cel-OD (250 mm × 4.6 mm × 10 μm) using mobile phase consisting of
n-hexane and ethanol in the ratio 9:1 (v/v) with a flow rate of 1.0 mL min−1, at 27 °C column temperature and detection at 254 nm with an injection volume of 20 μL. Ethanol was used as diluent. The
method is capable of detecting the (2S, 3R) enantiomer down to 0.0075% and can quantify down to 0.021% with respect to sample concentration. The method is rapid and
the resolution achieved was about 3.0. This method can be employed for the quantification of (2S, 3R) enantiomer in voriconazole drug substance. 相似文献
30.
The electron impact (EI) and chemical ionization (CI) spectra of 2,2-diphenyl-3-aryl cyclobutanone oximes (1–5) are reported. Formation of diphenylmethyl cation at m/z 167 is a major fragmentation process in both EI and CI spectra. Labelling studies established that the hydrogen involved in this rearrangement transfers from the NOH group and not from cyclobutane ring positions. The [M + 3]+ ions are formed under CI conditions as a result of C?N double bond reduction. An interesting secondary kinetic isotope effect is observed in the formation of ion e at m/z 183 in both EI and CI spectra. Other characteristic fragmentation pathways occurring in the EI and CI spectra of these compounds are outlined. 相似文献