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811.
A. Ya. Strakov Yu. B. Sliede M. V. Petrova A. F. Mishnev A. A. Kemme 《Chemistry of Heterocyclic Compounds》1996,32(4):435-440
The condensation of 6, 6-dimethyl-4, 5-dioro-l -phenyl-4, 5, 6, 7-tetrahydroindazole with the 1, 3-cyclanediones 1,3-indanedione and barbituric acid in the presence of piperidine acetate gave 4-(1,3-indanedion-2-ylidene)-and 4-(2, 4, 6-trioxo-4, 5-dihydro-5 pyrimidylidene)-5-oxo-l -phenyl-4, 5, 6, 7-tetrahydroindazoles respectively. With hydrazine hydrate the former readily gave 4, 4-dimethyl-12-oxo-3-phenyl-4, 5-dihydro-10H-indeno(3, 2-c]pyrazolo(4, 5-flcinnoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 501–507, April, 1996. 相似文献
812.
Electron-impact studies of diazadiphosphetidines,[YF2PNMe]2(Y? F,Me, Ph, MeO,2,5-Me2C6H3, and m-CF3C6H4) are reported, the most abundant fragments corresponding to m/e [M/2–1]+, [M/2]+ and [M/2–1]+. It is concluded from metastable data that formation of the noval rearrangement ion, [M]+→[M/2+1]+is predominantly due to an electron-impact process. Variable temperature spectra of(F3PNMe)2, (i.e. for Y=F), suggest that ions of m/e [M/2-1]+are formed, in part, by a thermal process. For the compound [(m-CF3C6H4)F2PNMe]2 a well resolved negative ion spectrum has been obtained, with the molecular ion present in 100% abundance. 相似文献
813.
814.
Negative chemical ionization mass spectrometry is used as a probe to examine reactions between hydrocarbon radicals and metal complexes in the gas phase. The methane negative chemical ionization mass spectra of 27 complexes of cobalt(II ), nickel(II ) and copper(II ) in the presence of O4, O2N2 and N4 donor atom sets are characterized by two dominant series of adduct ions of the form [M + CnH2n]? and [M + CnH2n+1]? at m/z values above the molecular ion, [M]?. Insertion of the CH radical into the ligand followed by radical/radical recombination and electron capture is proposed as the major mechanism leading to the formation of [M + CnH2n]? adduct ions. A second pathway involves ligand substitution by CnH2n+1 radicals concomitant with H elimination and electron capture. Oxidative addition at the metal followed by ionization is suggested as the principal pathway for the formation of [M + CnH2n+1]? adduct ions. 相似文献
815.
Gregor Högenauer 《Monatshefte für Chemie / Chemical Monthly》1967,98(2):494-500
Zusammenfassung Für ein neues Verfahren zur Untersuchung von Codon—Anticodon-Wechselwirkungen wurden radioaktive Trinukleotide mit möglichst hohen spezif. Aktivitäten im Milligrammaßstab benötigt. Zu ihrer Gewinnung wurde ausE. coli und Bäckerhefe, die in32P-phosphathältigen Nährmedien gezüchtet worden waren, die Gesamt-RNA isoliert und enzymatisch hydrolysiert. Das dabei entstandene Oligonukleotidgemisch wurde durch Papierchromatographie und Elektrophorese aufgetrennt, wobei elf markierte Trinukleotide in reiner Form erhalten werden konnten.
Mit 3 Abbildungen 相似文献
For the study of codon-anticodon interactions radioactive trinucleotides with high specific activities had to be prepared in milligram quantities. Labelled RNA was obtained fromE. coli and baker's yeast grown in a medium containing32P-phosphate. The RNA was hydrolyzed with enzymes and the resulting oligonucleotide mixture separated by paper chromatography and electrophoresis. Eleven pure, labelled trinucleotides were isolated by this procedure.
Mit 3 Abbildungen 相似文献
816.
Stanetty P Hattinger G Schnürch M Mihovilovic MD 《The Journal of organic chemistry》2005,70(13):5215-5220
A novel, short, and efficient synthetic pathway to 3-{4-[2-(3-chlorophenylamino)-pyrimidin-4-yl]-pyridin-2-ylamino}-propanol (CGP 60474) and a series of analogues was developed. The synthetic sequence consisted of a Negishi-type cross-coupling reaction in the key step followed by two subsequent nucleophilic substitution reactions. This strategy represents a versatile and robust protocol to access diverse analogues of the title compound for subsequent SAR studies as potential phenylamino-pyrimidine type protein kinase C inhibitors. 相似文献
817.
Reduction of [Cr(N(3)N)] (1) [(N(3)N)(3)(-) = ((SiMe(3)NCH(2)CH(2))(3)N)(3)(-)] with sodium powder in THF affords the yellow, extremely air-sensitive amidochromate(II) [Na(THF)(2)Cr(N(3)N)] (2) in good yield. Complex 2 has an effective magnetic moment of 5.1 mu(B) indicative of a d(4) high-spin electronic configuration. (1)H NMR spectroscopy in solution and single-crystal X-ray crystallography show that compound 2 is composed of idealized C(s) symmetric contact ion pairs, in which trigonal-monopyramidal [Cr(II)(N(3)N)](-) anions are linked to the [Na(THF)(2)](+) countercations by two bridging amide ligands. DFT calculations of 1, 2, and the anion [Cr(N(3)N)](-) at the RI-BP86/TZVPP level of theory provide in combination with extended Hückel calculations a rationale for the observed structural changes from 1 to 2. 相似文献
818.
The average recovery for 12 pesticides spiked into 100 ml of water at 0.1 ppb was 90% when cartridges containing 100 mg of C-18 bonded porous silica were used for adsorption. Flow rates of up to 200 bed volumes per minute were employed for the adsorption step. Quantitative desorption of the pesticides was accomplished with less than 100l of solvent, thus eliminating the need for a solvent reduction step. The pesticides from samples of surface waters were adsorbed onto C-18 bonded porous silica at the sampling site and the cartridges containing the bonded phase were returned to the laboratory for elution and analysis. The analytical results obtained from use of this procedure agreed with those obtained for duplicate samples of the water that were processed in the laboratory using standard solvent extraction procedures. 相似文献
819.
Hamid Reza Nasiri M. Gregor Madej C. Roy D. Lancaster Harald Schwalbe Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):o671-o673
The title compound, C14H12O4, forms crystals which appear monoclinic but are actually twinned triclinic. The asymmetric unit consists of two similar molecules, which differ only in the conformation of the 3‐oxobutyl side chain. The molecular conformation is characterized by an intramolecular O—H⋯O hydrogen bond between the hydroxy group and the adjacent carbonyl O atom. The crystal structure is stabilized by O—H⋯O hydrogen bonds connecting the molecules into zigzag chains running along the b axis. 相似文献
820.
Malcolm H. Mac Gregor 《Foundations of Physics Letters》1995,8(2):135-160
From the perspective of physical realism (PR), a photon is a localized entity that carries energy and momentum, and which is surrounded by a wave packet (anempty wave) that is devoid of observable energy or momentum. In creating quantized PR basis states for a photon wave packet, three requirements must be met:(1) The basis states must each carry the frequency of the wave;(2) They must closely resemble the photon, so that e.g. they scatter in the same manner from an optical mirror;(3) They must have infinitesimal energy, linear momentum, and angular momentum. An essentially zero-energy "empty wave" quantum-a "zeron"-is defined which meets these requirements. It is created as an asymmetric single-particle (or single-antiparticle) excitation of the vacuum state, with the "particle" (or "antiparticle") and its associated "hole" (or "antihole") forming a rotational bound state. The photon is reproduced as a symmetric particle-antiparticle excitation of the vacuum state, with the "particle" and "antiparticle" also forming a rotational bound state. The relativistic transformation problem is discussed. A key point in this development is the deduction of the correct equation of motion for a "hole" state in an external electrostatic field. 相似文献