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151.
Reactions of a Dibismuthane and of Cyclobismuthanes with Metal Carbonyls ‐ Syntheses of Complexes with R2Bi‐, RBi‐, Bi2‐ and Bin‐ligands (R = Me3CCH2, Me3SiCH2) Reactions of [Fe2(CO)9] with [(Me3CCH2)4Bi]2 or cyclo‐(Me3SiCH2Bi)n (n = 3 ‐ 5) lead to the complexes [(R2Bi)2Fe(CO)4], [RBiFe(CO)4]2[R = Me3CCH2, Me3SiCH2] and [Bi2Fe3(CO)9]. [Bi2{Mn(CO)2C5H4CH3}3] forms in a photochemical reaction of [Mn(CO)3C5H4CH3] with cyclo‐(Me3SiCH2Bi)n. 相似文献
152.
In the OSF(4)/Me(2)NSiMe(3) system besides the long known Me(2)NS(O)F(3) only the trisubstituted derivative is isolated as (Me(2)N)(3)SO(+)Me(3)SiF(2)(-) (3). Similar to (Me(2)N)(3)S(+)Me(3)SiF(2)(-) compound 3 is an excellent fluoride ion donor. With AsF(5) and HF the corresponding hexafluoroarsenate (Me(2)N)(3)SO(+)AsF(6)(-) (4) and the hydrogen bifluoride (Me(2)N)(3)SO(+)HF(2)(-) (5) are formed in almost quantitative yield. X-ray structure determinations of 3-5 surprisingly showed two different types of structures for the cation. In 3 and 5 this cation has C(3) symmetry, while in the hexafluoroarsenate 4 a (Me(2)N)(3)S(+)-like structure with C(s)() symmetry is determined. The experimental results for (Me(2)N)(3)SO(+) and (Me(2)N)(3)S(+) are compared with theoretical calculations for these cations and their isoelectronic neutral counterparts, the phosphorus amides (Me(2)N)(3)PO and (Me(2)N)(3)P, respectively. 相似文献
153.
In the reaction of TAS-fluoride, (Me2N)3S+Me3SiF2-, with carbonyl sulfur difluoride imides RC(O)NSF2 (R = F, CF3), C-N bond, cleavage is observed, and TAS+RC(O)F2- and NSF are the final products. From TASF and RC(O)NS(CF3)F, the salts TAS+RC(O)NS(CF3)F2- (R = F (14), CF3 (15)), with psi-pentacoordinate sulfur centers in the anions, are formed. An X-ray structure investigation of 14 shows that the fluorine atoms occupy axial positions and CF3, NC(O)F, and the sulfur lone pair occupy equatorial positions of the trigonal bipyramid. The -C(O)F group lies in the equatorial plane with the CO bond synperiplanar to the SN bond. According to B3LYP calculations, this structure corresponds to a global minimum and the expected axial orientation of the -C(O)F group represents a transition state. Calculations for the unstable FC(O)NSF3- anion show a different geometry. The -C(O)F group deviates 40 degrees from axial orientation, and the equatorially bonded fluorine is, in contrast to the -CF3 group in 14, syn positioned. 相似文献
154.
TAS Indolide and TAS Carbazolide: Structures of [TAS]+[IndHInd]? and [TAS]+[Carb]?·½CarbH From the reaction of TAS‐fluoride [(Me2N)3S]+[Me3SiF2]? with trimethylsilyl‐indole and trimethylsilyl‐carbazole TAS‐indolide and TAS‐carbazolide are formed. During crystallisation partially protonation to indole and carbazole occurs, resulting in the formation of [TAS]+[IndHInd]? ( 3a ) and [TAS]+[Carb]?·½CarbH ( 5a ) according to X‐ray analysis. 相似文献
155.
Selected imines reacted with hexafluoroacetone non-catalyzed at ambient temperature to give β-hydroxy-β-bis(trifluoromethyl) imines in good to excellent yields. For the imines of acetone, pentan-3-one, and of cyclohexanone a 1:2 reaction was observed giving iminodiols; for N,N′-bis(propylidene)ethylene diamine an iminotetrol was formed. The diol derivative of N-isopropyl-propylidene amine could be deprotonated and O-methylated furnishing the respective ethers. Hexafluoropropylidene amine reacted with N-isopropyl-propylidene amine, unlike hexafluoroacetone, in a 1:1 manner to form an amino-imino alcohol which in its turn is able to add hexafluoroacetone. The imines of acetophenone, trifluoroacetone, 2,4-dimethyl-pentan-3-one, 2,6-dimethyl-cyclohexanone and of acetaldehyde added hexafluoroacetone to furnish β-iminoalcohols. A multifunctional β-hydroxy enaminone was obtained from 4-isopropylamino-pent-3-en-2-one. The molecular structures of the novel β-hydroxy-β-bis(trifluoromethyl) imines exhibit strong (R)N?HO hydrogen bonds. 相似文献
156.
TAS+[P4N4F8NMe2]? ( 2 ) was prepared from TAS+[P4N4F9]? ( 1 ) via F/NMe2 exchange using Me3SiNMe2. The salt was characterised by nmr‐spectroscopy and by X‐ray crystallography. The bonding situation in the anion is briefly discussed. The structural properties of the anion are compared with those of the starting material. 相似文献
157.
In the system PbF2/AsF5/anhydrous hydrogen fluoride (aHF) two new lead(II) hexafluoroarsenates(V) Pb(HF)(AsF6)2 and PbFAsF6 were isolated. Pb(HF)(AsF6)2 is formed when the molar ratio AsF5:PbF2 is 2 or higher. It crystallizes in the space group Pbcn with a=1058.3(3) pm, b=1520.9(6) pm, c=1079.4(3) pm, V=1.7374(10) nm3 and Z=8. The HF molecule is directly connected to the Pb center, eight fluorine atoms from three different AsF6− ions (Pb–F distances ranging from 248(4) to 276(2) pm) and one further fluorine at 306(3) pm complete the coordination sphere. PbFAsF6 is obtained when equimolar amounts of PbF2 and AsF5 react in aHF. PbFAsF6 crystallizes in the space group P
with: a=466.10(10) pm, b=723.70(10) pm, c=747.40(10) pm, =105.930(10)°, β=101.49(2)°, γ=90.660(10)°, V=0.23698(7) nm3 and Z=2. The basic unit in the structure of PbF(AsF6) consists of a four-membered ring of two Pb and two F atoms. The Pb atoms in the ring are further connected by two AsF6− units via cis-fluorine bridges, thus forming a [PbF(AsF6)]2 cluster, which interacts by additional Pb–F bonds thus forming a ribbon-like polymer. 相似文献
158.
159.
Frank Seela Enno Schweinberger Venkata Ramana Sirivolu Helmut Rosemeyer 《Tetrahedron》2007,63(17):3471-3482
The synthesis of 1,N6-etheno-7-deaza-2′-deoxyadenosine (12b) which was prepared from 7-deaza-2′-deoxyadenosine (5a) with chloroacetaldehyde is described. Also the regioselective glycosylation of the 7-deazapurine-2-one at nitrogen-1 (19) furnishing the pyrrolo-C nucleoside 7a is reported and a side chain derivative with a terminal triple bond (7d) is prepared. The fluorescence properties of these nucleosides and related compounds were determined. The etheno nucleoside 12b is strongly fluorescent showing a Stokes shift of 134 nm and a quantum yield of Φ=0.53. It proved to be stable, both in acidic and in alkaline medium while the parent purine compound 10b is labile under both conditions. Compound 12b was converted into its phosphoramidite 14 and was incorporated into oligonucleotides. Compound 12b destabilizes oligonucleotide duplexes when it is located in the center of the molecule; it stabilizes when it is incorporated in the terminal base pair or acts as an overhanging nucleoside. Temperature-dependent fluorescent measurements yielded sigmoidal melting profiles when compound 12b is stacked to the terminal base pair while a linear decrease of the fluorescence is observed when the molecule is located opposite to the four canonical nucleosides in the center of the duplex. 相似文献
160.