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101.
Jerry F. Bott 《Chemical physics letters》1973,23(3):335-338
The energy transfer rate for the reaction DF (ν=1) + DF (ν=1)kνν→ DF (ν=0) + DF (ν=2) + ΔE=91.6 cm?1 has been studied in a combined shock-tube laser-induced fluorescence experiment at temperatures from 295 to 720°K. The rate coefficient kνν for the exothermic reaction was found to vary as T?1 when expressed in units of cm3/mole sec. At T=295°K, the probability of the reaction is approximately 0.2 per collision. 相似文献
102.
The reaction of the heterometallic vinylidene cluster RuCo2(CO)9(3-2-C=CHPh) with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) proceeds readily in the presence of Me3NO to furnish the new cluster RuCo2(CO)7(bpcd)(3-2-C=CHPh) as the sole product. This cluster has been isolated by preparative chromatography and characterized in solution by IR spectroscopy. The molecular structure was determined by X-ray diffraction analysis, which has confirmed the chelation of the bpcd ligand to the ruthenium center and the change in the coordination mode exhibited by the vinylidene ligand. RuCo2(CO)7(bpcd)(3-2-C=CHPh) crystallizes in the triclinic space group P
, a = 10.5788(9), b = 11.909(1), c = 19.526(2) Å, = 84.491(9)°, = 78.068(8)°, = 63.760(7)°, V = 2158.7(4) Å3, Z = 2, and d
calc = 1.581. 相似文献
103.
Simon G. Bott Huafeng Shen Michael G. Richmond 《Journal of organometallic chemistry》2008,693(13):2327-2337
The reaction of the methylidyne-bridged cluster HRu3(CO)10(μ-COMe) (1) with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) and Me3NO furnishes HRu3(CO)8(μ-COMe)(bpcd) (2) and HRu3(CO)8(Ph2PH)[μ-PPh2CCC(O)CH2C(O)] (3) as the major and minor products, respectively. The 1H and 31P NMR data indicate that the bpcd ligand in 2 is chelated to one of the ruthenium atoms that is bridged by the hydride and methylidyne ligands. Thermolysis of 2 is accompanied by P-Ph bond cleavage and elimination of benzene to yield Ru3(CO)7(μ3-COMe)[μ-P(Ph)CC(PPh2)C(O)CH2C(O)] (4). Compound 4 consists of a triangular ruthenium core that is face-capped by μ3-COMe methylidyne and μ-P(Ph)CC(PPh2)C(O)CH2C(O) phosphido ligands. The kinetics for the conversion of 2 → 4 have been measured in toluene solvent over the temperature range 320-343 K, and based on the observed activation parameters and the inhibitory effect of added CO on the reaction, a rate-limiting step involving a dissociative loss of CO is supported. Heating 4 in the presence of H2 afforded the phosphinidene-capped cluster H3Ru3(CO)7(μ3-PPh)[μ-CC(PPh2)C(O)CH2C(O)] (5). Crystallographic analysis of 5 has confirmed the loss of the methylidyne moiety and the cleavage of the phosphido PhP-C(dione) bond, and the presence of three edge-bridging hydrides is supported by 1H NMR spectroscopy. The reaction of 4 with added PPh3 and PMe3 has been investigated; the uptake of a single phosphine ligand occurs regiospecifically at one of the phosphido-bound ruthenium centers to give Ru3(CO)6L(μ3-COMe)[μ-P(Ph)CC(PPh2)C(O)CH2C(O)] (PPh3, 6; PMe3, 7). Compound 6 contains 48e- and exhibits a structural motif similar to that found in 4. Compound 7 readily adds a second PMe3 ligand to yield the bis-substituted cluster Ru3(CO)6(PMe3)2(μ2-COMe)[μ-P(Ph)CC(PPh2)C(O)CH2C(O)] (8). The solid-state structure of 8 confirms the loss of two ruthenium-ruthenium bonds and the conversion of the original face-capping μ3-COMe ligand to a μ2-COMe moiety that tethers two non-bonding ruthenium centers. The two PMe3 ligands in 8 coordinate to the same ruthenium center, and the 9e- P(Ph)CC(PPh2)C(O)CH2C(O) ligand binds all three ruthenium atoms through the phosphine, phosphido, alkene, and carbonyl moieties. Near-UV irradiation of 8 leads to loss of CO and polyhedral contraction of the triruthenium frame to yield the 48e- cluster Ru3(CO)5(PMe3)2(μ3-COMe)[μ-P(Ph)CC(PPh2)C(O)CH2C(O)] (9). 相似文献
104.
Study of three-dimensional structure in wire-array z pinches by controlled seeding of axial modulations in wire radius 总被引:1,自引:0,他引:1
Jones B Deeney C McKenney JL Garasi CJ Mehlhorn TA Robinson AC Wunsch SE Bland SN Lebedev SV Chittenden JP Bott SC Ampleford DJ Palmer JB Rapley J Hall GN Oliver BV 《Physical review letters》2005,95(22):225001
Three-dimensional perturbations have been seeded in wire-array z pinches by etching 15 microm diameter aluminum wires to introduce 20% modulations in radius with a controlled axial wavelength. These perturbations seed additional three-dimensional imploding structures that are studied experimentally and with magnetohydrodynamics calculations, highlighting the role of current path nonuniformity in perturbation-induced magnetic bubble formation. 相似文献
105.
Simon G. Bott Jian Cheng Wang Michael G. Richmond 《Journal of chemical crystallography》1999,29(5):587-595
Thermolysis of the cluster Ru3(CO)12 with the bis(phosphanyl)hydrazine ligand (MeO)2PN (Me)N(Me)P(OMe)2 (dmpdmh) in toluene at 75°C furnishes the known clusters Ru4(CO)12 [-N(Me)N(Me)] (2) and Ru3(CO)11[P(OMe)3] (3), in addition to the new cluster Ru3 (CO)10(dmpdmh) (1) and the phosphite-tethered cluster Ru3(CO)9[-P(OMe)3] (4). The simple substitution product Ru3(CO)10(dmpdmh), a logical intermediate to clusters 2–4, was synthesized by treating Ru3(CO)12 with Me3NO in CH2Cl2 at room temperature, and independent thermolysis reactions using cluster 1 was shown to yield clusters 2–4. The solid-state structure of clusters 2 and 4 were unequivocally established by X-ray diffraction analysis. Ru4(CO)12[-N(Me)N(Me)] crystallizes in the orthorhombic space group Pnna (#52), a = 12.913(1), b = 13.3238(6), c = 12.5690(8) Å, V = 2162.5(2) Å3, Z = 4, and d
calc = 2.452 g/cm3. Ru3(CO)9[-P(OMe)3] crystallizes in the triclinic space group P
a = 9.586(1), b = 14.354(1), c = 14.997(2) Å, = 89.82(1)°, = 98.36(1)°, = 92.010(8)°, V = 2040.4(4) Å3, Z = 4, and d
calc = 2.212 g/cm3. The coordination of the dimethylazo linkage to the four ruthenium atoms in 2 and the phosphorus atom and one of the oxygen atoms of the methoxy groups to the three ruthenium centers in 4 are confirmed by X-ray analysis. 相似文献
106.
The pinacol resulting from sodium promoted reductive coupling of pentacyclo[5.4.0.02,6.-03,10.05,9]undecane-8,11-dione monoethylene ketal possesses a conformation, dictated by intramolecular hydrogen bonding, that lies midway between eclipsed and staggered. The C–C and C–O distances in the pinacol unit are, respectively, longer and shorter than usual, and all parameters are as expected. 相似文献
107.
Simon G. Bott Alan P. Marchand Vijay R. Gadgil 《Journal of chemical crystallography》1995,25(5):215-218
The structure of the cyclic sulfite derived from the reaction of thionyl chloride withendo-8-hydroxy-exo-8-(endo-8-hydroxypentacyclo[5.4.0.0.2,6.03,10.05,9]undec-exo-8-yl)pentacyclo-[5.4.0.0.2,6.03,10.05,9]undecane is reported. All bond lengths and angles are consistent with the strained cage geometry. A static disorder of the terminal oxygen was found to be present. 相似文献
108.
Kaiyuan Yang Simon G. Bott Michael G. Richmond 《Journal of chemical crystallography》1995,25(5):263-266
The reaction betweencis-Ru(bpy)2Cl2 (where bpy=bipyridine) and the diphosphine ligand 1,1-bis(diphenylphosphino)ferrocene (dppf) in the presence of AgBF4 has led to the isolation of the title compound [Ag(dppf)Cl]2. [Ag(dppf)Cl]2 has been structurally characterized by X-ray diffraction analysis, which confirms the bridging mode adopted by the ancillary dppf ligand and the centrosymmetric nature of this molecule. Dimeric [Ag(dppf)Cl]2 crystallizes in the triclinic space group
,a=11.426(1) Å,b=11.509(1) Å,c=12.786(1) Å, =68.96(2)°, =70.66(2)°, =71.24(2)°,V=1441(1) Å3,Z=1,d
calc=1.608 g·cm–3;R=0.0445,R
w=0.0566 for 4486 observed reflections withl>3(l) 相似文献
109.
110.
Gregory H. Robinson Simon G. Bott Hosny Elgamal William E. Hunter Jerry L. Atwood 《Journal of inclusion phenomena and macrocyclic chemistry》1985,3(1):65-69
The crown ether 12-crown-4 reacts with trimethylaluminum in toluene to form the complex [AlMe3]2[12-crown-4]. Attempts to utilize the remaining two oxygen atoms for coordination to AlMe3 molecules were unsuccessful. The 21 complex crystallizes in the monoclinic space groupP21/n witha=11.342(7),b=12.941(4),c=6.973(6) Å, and =95.48(4)°. Refinement led to a finalR value of 0.047 for 925 observed reflections. The molecule resides on a crystallographic center of inversion, and as required by symmetry, the four oxygen atoms are planar. The Al–O bond is strong as revealed by the bond length of 1.977(3) Å.
Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82013 (9 pages). 相似文献