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81.
82.
Alfred Courtin 《Helvetica chimica acta》1983,66(1):68-75
Syntheses of Sulfonated Derivatives of 2-Fluoroaniline Synthesis of 4-amino-3-fluorobenzenesulfonic acid ( 3 ) was achieved in two ways: reaction of 2-fluoroaniline ( 1 ) with amidosulfonic acid and by first conventionally converting 4-nitro-3-fluoroaniline ( 8 ) to 4-nitro-3-fluorobenzenesulfonyl chloride ( 9 ) followed subsequently by hydrolysis to 3-fluoro-4-nitrobenzenesulfonic acid ( 10 ) and reduction. Hydrogenolysis of 3 gave sulfanilic acid ( 7 ). Both, sulfonation of fluorobenzene ( 6 ) to 4-fluorobenzenesulfonic acid ( 11 ) followed by nitration and sulfonation of 1-fluoro-2-nitrobenzene ( 12 ) led to 4-fluoro-3-nitrobenzenesulfonic acid ( 13 ). Reduction of 13 gave the isomeric 3-amino-4-fluorobenzenesulfonic acid ( 4 ), which was also obtained both by sulfonation of 1 and by sulfonation of o-fluoroacetanilide ( 14 ) followed by hydrolysis. Selective hydrogenolyses of 2-amino-5-bromo-3-fluorobenzenesulfonic acid ( 15 ), prepared by reaction of 4-bromo-2-fluoroaniline ( 16 ) with amidosulfonic acid, and of 4-amino-2-bromo-5-fluorobenzenesulfonic acid ( 20 ), obtained by sulfonation of 5-bromo-2-fluoroaniline ( 19 ) yielded the isomers 2-amino-3-fluorobenzenesulfonic acid ( 5 ) and 3 , respectively. The fourth isomer, 3-amino-2-fluorobenzenesulfonic acid ( 2 ), was synthesized by sulfur dioxide treatment of the diazonium chloride derived from 2-fluoro-3-nitroaniline ( 21 ) to 2-fluoro-3-nitrobenzenesulfonyl chloride ( 22 ), followed by hydrolysis to 2-fluoro-3-nitrobenzenesulfonic acid ( 23 ) and final Béchamp-reduction. 相似文献
83.
84.
Alfred Eckert 《Monatshefte für Chemie / Chemical Monthly》1917,38(1):1-10
Ohne Zusammenfassung 相似文献
85.
Ohne Zusammenfassung 相似文献
86.
87.
88.
Wooten A Carroll PJ Maestri AG Walsh PJ 《Journal of the American Chemical Society》2006,128(14):4624-4631
This report describes the solid-state structures of a series of divinylzinc complexes, one of which represents the only structurally characterized zinc(II) pi-complex. Vinylzinc reagents, Zn[C(Me)=CH2]2 (1) and Zn[C(H)=CMe2]2 (2), have been synthesized and isolated as white crystalline solids in 66 and 72% yield, respectively. Each compound exhibits an infinite polymeric architecture in the solid state via a series of zinc-pi (1) and zinc-sigma-bonded (2) bridging interactions. Addition of chelating ligands to these divinylzinc compounds allowed isolation of the monomeric adducts (bipy)Zn[C(Me)=CH2]2 (1.bipy), (tmeda)Zn[C(Me)=CH2]2 (1*tmeda), (bipy)Zn[C(H)=CMe2]2 (2*bipy), and (tmeda)Zn[C(H)=CMe2]2 (2*tmeda), of which 1*bipy, 2*bipy, and 2*tmeda have been characterized crystallographically. 相似文献
89.
Alfred D. French 《Cellulose (London, England)》2011,18(4):889-896
Thorough conformational study of cellobiose requires consideration of numerous arrangements of the exocyclic groups. Therefore,
it is customary to prepare a number of structures with different arrangements of hydroxyl and hydroxymethyl groups. These
“starting geometries” are then given different values of the glycosidic linkage torsion angles ϕ and ψ. At each increment
of ϕ and ψ, the energy is calculated. Usually, the final product is an “adiabatic” contour plot of the lowest energy at each
ϕ/ψ point after considering all of the starting geometries. The present paper advocates for adiabatic maps despite the statement
by Schnupf and Momany (preceding paper) that adiabatic maps are not of interest because they contain sparse details about
the structures at each minimum. Similar information is computed by their method and adiabatic mapping, and comparable details
can be provided from adiabatic studies. Although Schnupf and Momany presented maps from calculations in vacuum and in water
that considered all of their calculated energies, they favored the presentation of two to four maps for each of 36 individual
minima, each with its own zero of relative energy. However, previous work showed that more structures are needed to provide
the lowest energies at each point in ϕ/ψ space. Following their preferred strategy would result in even more maps when the
added structures are considered. The need to map individual minima can be avoided by starting calculations with the same exocyclic
orientations at each ϕ/ψ point instead of using the preceding optimized structure to start the next energy minimization. Using
the same orientations at each point allows periodic maps that depict barriers between minima. 相似文献
90.
Dieter Weber Günther Burget Karl-Heinz Zirzow Hans Georg Von Schnering Alfred Schmidpeter 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract Alkalimetal diphenylphosphinites degrade (Ph-P)5 and P4 to give anions containing a chain of 2, 3 or 4 four- and two-coordinated phosphorus atoms. Representatives of the chain with two four-coordinated and one two-coordinated P atoms became first available from the aminolysis of tris (phosphoryl)phosphides1. 相似文献