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991.
Antonín Kyselka 《International Journal of Theoretical Physics》1981,20(1):13-17
The use of complex mass in nonrelativistic quantum mechanics and its relation to the influence of vacuum field fluctuation in electron motion are discussed. 相似文献
992.
Prof. Dr. Anton Meller Hans J. Füllgrabe 《Monatshefte für Chemie / Chemical Monthly》1975,106(6):1407-1413
Bis-(trimethylsilyl)acetamide (BSA) reacts with borazines [RNBX]3, R=H,X=F; R=CH3,X=F; R=C6H5,X=F and R=C6H5,X=Cl to the corresponding borazines,X=OSi(CH3)3. The1H-NMR signal of the Si(CH)3-groups of [C6H5NBOSi(CH3)3]3 is at abnormally high field. With [CH3NBCl]3,BSA forms borazines which contain both Si(CH3)3O- and O?C(CH3)=NSiR3 groups bonded to the boron atoms. With LiN[Si(CH3)3]2, [CH3NBCl]3 forms silylaminoboranes.1H-NMR, mass spectrometric and analytical data are reported. 相似文献
993.
The Ugi three-component reaction with 2-substituted five-, six-, and seven-membered cyclic imines was investigated. The reaction opens a new route to substituted proline and homoproline derivatives. It was shown that the method is efficient for the one-step preparation of seminatural dipeptides containing natural amino acid residues, and fragments of substituted proline or pipecolinic acid. The scope and limitation of the approach are discussed. 相似文献
994.
Anton P. Koskin Irina L. Simakova Valentin N. Parmon 《Reaction Kinetics and Catalysis Letters》2007,92(2):293-302
Polycyclic nitramine hexanitrohexaazaisowurtzitane (HNIW, CL-20) is synthesized via hydrodebenzylation of a precursor over
palladium-based catalyst. In the present work, we studied the influence of the synthesis method of the palladium-based catalyst
on the catalyst behavior during the hydrodebenzylation reaction of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9] dodecane. 相似文献
995.
Anton Hammerl Thomas M. Klapötke Prof. Dr. Burkhard Krumm Matthias Scherr 《无机化学与普通化学杂志》2007,633(10):1618-1626
The tellurenyl fluoride, 2‐Me2NCH2C6H4TeF, was obtained from reaction of the tellurenyl iodide RTeI with AgF. The compound was unambiguously identified by 19F and 125Te NMR spectroscopy. The decomposition under disproportionation leads to the tellurium(IV) trifluoride, 2‐Me2NCH2C6H4TeF3 and the ditelluride RTeTeR. The fluorination of the ditelluride, (2‐Me2NCH2C6H4Te)2, with XeF2 results in pure RTeF3. The molecular structure of 2‐Me2NCH2C6H4TeF3, the second structural characterized tellurium(IV) trifluoride, has been determined. Furthermore the syntheses of the new tellurium(IV) difluoride, (2‐Me2NCH2C6H4)2TeF2, and corresponding tellurium(IV) diazide, (2‐Me2NCH2C6H4)2Te(N3)2 as well as the tellurium(IV) triazide, 2‐Me2NCH2C6H4Te(N3)3, and their characterization by spectroscopic methods were reported. During these investigations a rather interesting tellurium(VI) species was formed and the molecular structure of a subsequent product, [(2‐Me2NHCH2C6H4)2TeF3O]2(SiF6), was elucidated. Theoretical investigations for the compounds containing the stabilizing 2‐dimethylaminomethylphenyl substituent are illustrated. 相似文献
996.
M. Anton K. -H. Schartner D. Hasselkamp A. Scharmann 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,18(1):53-59
Collisions of He+- and Ne+-projectiles with He at impact energies between 90 keV and 800 keV were investigated. Relative excitation cross sections for magnetic sublevels of He—41 D were determined using level-crossing techniques. Absolute excitation cross sections σ m of the Zeeman-sublevels are given using He—41 D cross sections from earlier measurements. The results show strong variations of the cross sections σ0 and σ±1 with a quasi-oscillatory behaviour. σ±2 is much smaller than σ0 and σ±1. 相似文献
997.
In exploring versatile synthetic routes to (E)-allylamine derivatives with antimycotic properties, a new method has been found in the trans-reduction of tertiary 2-alkinylanunes by diisobutylaluminum hydride (DIBAH). The stereoselectivity of this reaction, which is in contrast to the well-known cis-hydroalumination of disubstituted alkynes, and the regioselectivity have been studied in detail. Tertiary 2-alkinylamines 1 were generally reduced to (E)-2-alkenylamines 2 in toluene at 40°, and tertiary 2,4-alkadiynylamines 3 yielded a mixture of(E)-2-alken-4-ynylamines 4 and 2(E),4(Z)-alkadienylamines 5 in high stereochemical purity. This reduction was clearly different with respect to reactivity and selectivity in comparison with other reactions also proceeding via trans-hydroalumination, namely the lithium aluminum hydride reduction of α-hydroxyacetylenes and the reaction of alkynes with LiAlH(iso-Bu)2(n-Bu). Tertiary 6-hydroxy-2, 4-alkadiynylamines 10 were reduced to 6-hydroxy-2(E)-alken-4-ynylamines 11 with diisobutylaluminum hydride, whereas on treatment with lithium aluminum hydride 6-hydroxy-4(E)-alken-2-ynylamines 12 were obtained. LiAlH (iso-Bu)2(n-Bu) did not react with 2-alkinylamine 1a and the 2,4-alkadiynylamine 3a was only monohydroaluminated without discrimination of the two acetylene groups. A possible mechanism for the diisobutylaluminum hydride reduction of 2-alkinylamines is presented. 相似文献
998.
W.H.J. de Beer Anton M. Heyns P.W. Richter J.B. Clark 《Journal of solid state chemistry》1980,33(3):283-288
CsSbF6(II) under ambient conditions is trigonal, space group . At 187.8°C it undergoes a phase transition with an enthalpy change of 5.267 ± 0.316 kJ mole?1, to phase CsSbF6(I). CsSbF6 decomposes with loss of fluorine at atmospheric pressure at high temperatures, but under pressure the decomposition is prevented and a melting point of 310°C at atmospheric pressure can be inferred. The phase boundary and melting curve were studied as functions of pressure. The infrared and Raman spectra of CsSbF6(II) were studied in the temperature range of ?256 to 20°C, at ambient pressure. The crystal chemistry of the CsSbF6 and its relationship with other related compounds is discussed. 相似文献
999.
Busby M Matousek P Towrie M Clark IP Motevalli M Hartl F Vlcek A 《Inorganic chemistry》2004,43(14):4523-4530
The lowest allowed electronic transition of fac-[Re(Cl)(CO)(3)(bopy)(2)] (bopy = 4-benzoylpyridine) has a Re --> bopy MLCT character, as revealed by UV-vis and stationary resonance Raman spectroscopy. Accordingly, the lowest-lying, long-lived, excited state is Re --> bopy (3)MLCT. Electronic depopulation of the Re(CO)(3) unit and population of a bopy pi orbital upon excitation are evident by the upward shift of nu(CO) vibrations and a downward shift of the ketone nu(C=O) vibration, respectively, seen in picosecond time-resolved IR spectra. Moreover, reduction of a single bopy ligand in the (3)MLCT excited state is indicated by time-resolved visible and resonance Raman (TR(3)) spectra that show features typical of bopy(*)(-). In contrast, the lowest allowed electronic transition and lowest-lying excited state of a new complex fac-[Re(bopy)(CO)(3)(bpy)](+) (bpy = 2,2'-bipyridine) have been identified as Re --> bpy MLCT with no involvement of the bopy ligand, despite the fact that the first reduction of this complex is bopy-localized, as was proven spectroelectrochemically. This is a rare case in which the localizations of the lowest MLCT excitation and the first reduction are different. (3)MLCT excited states of both fac-[Re(Cl)(CO)(3)(bopy)(2)] and fac-[Re(bopy)(CO)(3)(bpy)](+) are initially formed vibrationally hot. Their relaxation is manifested by picosecond dynamic shifts of nu(C(triple bond)O) IR bands. The X-ray structure of fac-[Re(bopy)(CO)(3)(bpy)]PF(6).CH(3)CN has been determined. 相似文献
1000.
Anton V Tverdokhlebov Elizaveta V Resnyanska Andrey A Tolmachev Alexander N Chernega 《Tetrahedron》2004,60(27):5777-5783
Alkylation of the title pyridinedicarbonitriles with N-substituted chloroacetamides was found to give 5,6-diamino-8-dialkylamino-2,3-dihydro-2-oxo-1H-pyrrolo[2,3-c]2,7-naphthyridine-9-carbonitriles. The structure of obtained compounds was unambiguously confirmed by X-ray crystallographic study. The heterocyclization reaction proceeded regioselectively involving 3-CN group of the starting pyridines without participation of 5-CN. The reasons of the selectivity were discussed. An interaction of prepared naphthyridine derivatives with acetic acid anhydride and cyclohexanone yielded 2-dialkylamino-6,8,9,10-tetrahydro-5-methyl-9-oxopyrimido[4,5,6-ij]pyrrolo[2,3-c]2,7-naphthyridine-1-carbonitriles and 2-dialkylamino-4,5,6,8,9,10-hexahydro-9-oxospiro{pyrimido[4,5,6-ij]pyrrolo[2,3-c]2,7-naphthyridine-5,1′-cyclohexane}-1-carbonitriles, respectively. All fused 2,7-naphthyridines obtained were derivatives of novel heterocyclic systems. 相似文献