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21.
Piotr Kowalski Marcin Marszałł Ilona Olędzka Wojciech Czarnowski 《Chromatographia》2007,66(5-6):357-361
Two rapid and popular methods—capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) have been compared
for analysis of cotinine in human urine. Cotinine was analyzed in less than 7 min, with detection limits of 5 and 3.2 ng mL−1 for CE and HPLC, respectively. The performance of the methods was evaluated in terms of sensitivity, specificity, precision,
accuracy, and limits of detection and quantification. Calibration plots were linear in the range 50–4,000 ng mL−1, at least, and mean recoveries were satisfactory for both techniques. The methods were successfully used for quantification
of cotinine in urine. 相似文献
22.
The methane oxidation catalyst [bpyrPtCl(2)] (bpyr = bis-pyrimidine) dissolves in superacidic HF/SbF(5) solution under formation of a dinuclear cation [H(2)bpyrPt(mu-Cl)(2)PtbpyrH(2)](6+). Two crystal forms are isolated, [Pt(2)Cl(2)bpyr(2)H(4)](6+)(SbF(6)(-))(4)(Sb(2)F(11)(-))(2).2HF (I) (triclinic, Ponemacr;, a = 814.8(2) pm, b = 1444.8(3) pm, c = 2300.5(5) pm, alpha = 89.627(4) degrees, beta = 84.285(4) degrees, gamma = 84.665(4) degrees, Z = 2) and [Pt(2)Cl(2)bpyrH(4)](6+)(Sb(2)F(11)(-))(6).4HF (II) (triclinic, Ponemacr;, a = 879.4(2) pm, b = 1170.4(3) pm, c = 1789.9(5) pm, alpha = 95.37(2) degrees, beta = 99.97(2) degrees, gamma = 100.41(2) degrees, Z = 1). The cation in I has an angle of 148.4(1) degrees between the two square plane platinum environments, while the cation in II is fully planar. The non-platinum-bound nitrogen atoms are all protonated in the superacidic medium. 相似文献
23.
24.
Under the assumptions thatq is not a root of unity and that the differentialsdu
j
i
of the matrix entries span the left module of first order forms, we classify bicovariant differential calculi on quantum groupsA
n–1
,B
n
,C
n
andD
n
. We prove that apart one dimensional differential calculi and from finitely many values ofq, there are precisely2n such calculi on the quantum groupA
n–1
=SL
q
(n) forn3. All these calculi have the dimensionn
2. For the quantum groupsB
n
,C
n
andD
n
we show that except for finitely manyq there exist precisely twoN
2-dimensional bicovariant calculi forN3, whereN=2n+1 forB
n
andN=2n forC
n
,D
n
. The structure of these calculi is explicitly described and the corresponding ad-invariant right ideals of ker are determined. In the limitq1 two of the 2n calculi forA
n–1
and one of the two calculi forB
n
,C
n
andD
n
contain the ordinary classical differential calculus on the corresponding Lie group as a quotient. 相似文献
25.
A -symmetric spaceM is a complete connected regular Sasakian manifold, that fibers over an Hermitian symmetric spaceN, so that the geodesic involutions ofN lift to define global (involutive) automorphisms of the Sasakian structure onM. In the present paper the complete classification of -symmetric spaces is obtained. The groups of automorphisms of the Sasakian structures and the groups of isometries of the underlying Riemannian metrics are determined. As a corollary, the Sasakian space forms are also determined. 相似文献
26.
The SCCC MO method has been used to calculate the electronic structure and spectrum of Mo(CN)
8
4–
and Mo(CN)
8
3–
ions of a D
4d
symmetry. All metal-ligand and ligand-ligand interactions and all overlap integrals (over products of HF atomic orbitals) have been included within the SCCC MO scheme. Basing on these calculations a new assignment of some absorption bands is proposed. The overall agreement between the calculated and observed electronic spectrum is satisfactory.
The authors are grateful to Prof. W. Jakób, Dr. Z. Stasicka and Dr. A. Samotus for many interesting discussions, to Prof. J. Chojnacki for providing us with new X-ray results before publication and to Dr. A. J. Sadlej for a help in dealing with the computer. 相似文献
Zusammenfassung Elektronenstruktur und Spektrum der [Mo(CN)8]–4- und [Mo(CN)8]–3-Ionen in D 4d -Symmetrie wurden mit der SCCC-MO-Methode berechnet. Alle Metall-Ligand- und Ligand-Ligand-Wechsel-wirkungen und Überlappungsintegrale wurden berücksichtigt. Die Bandenzuordnung wurde neu vorgenommen. Die Übereinstimmung der berechneten und gemessenen Spektren ist befriedigend.
Résumé Application à Mo(CN) 8 4– et Mo(CN) 8 3– de la méthode SCCC MO basée sur des orbitales atomiques HF approchées, en tenant compte du recouvrement et de toutes les interactions ligand-ligand. Dans la partie I on discute le cas de la symétrie D 4d . L'accord global avec l'expérience est satisfaisant en ce qui concerne les spectres. On montre aussi que toutes les attributions antérieures basées sur la théorie du champ cristallin semblent inadéquates.
The authors are grateful to Prof. W. Jakób, Dr. Z. Stasicka and Dr. A. Samotus for many interesting discussions, to Prof. J. Chojnacki for providing us with new X-ray results before publication and to Dr. A. J. Sadlej for a help in dealing with the computer. 相似文献
27.
Anna Kowalska Zygmunt Kowalski Andrzej Kotarba Andrzej Barański 《Mikrochimica acta》1990,100(5-6):349-353
The analytical procedure of determination of Fe(II) in the presence of Fe(III) in milligram samples is proposed. A solid sample is dissolved in hydrochloric acid in argon atmosphere. Subsequently, the pH-value of the solution is fixed and Fe(III) complexed by phosphoric buffer. At the next step Fe(II) is oxidized by -molybdosilicic acid. Finally, the intensity of colouring caused by the reduced form of the acid is measured at the wavelength 770 nm. The proper treatment of the sample during oxidation, and immediately before, is decisive for the accuracy of the analysis. The method was verified by means of the analysis of synthetic magnetite. The theoretical content of Fe(II) was 24.12%, the determined one was 24.02 ± 0.10%. The method was applied to the determination of the homogeneity of an iron catalyst for ammonia synthesis. 相似文献
28.
Summary We consider the problem of optimal quadratures for integrandsf: [–1,1] which have an analytic extension
to an open diskD
r
of radiusr about the origin such that
1 on
. Ifr=1, we show that the penalty for sampling the integrand at zeros of the Legendre polynomial of degreen rather than at optimal points, tends to infinity withn. In particular there is an infinite penalty for using Gauss quadrature. On the other hand, ifr>1, Gauss quadrature is almost optimal. These results hold for both the worst-case and asymptotic settings.This research was supported in part by the National Science Foundation under Grants MCS-8203271 and MCS-8303111This research was supported in part by the National Science Foundation under Grant MCS-8923676 相似文献
29.
LetP be a finite partially ordered set. The lengthl(x) of an elementx ofP is defined by the maximal number of elements, which lie in a chain withx at the top, reduced by one. Letw(P) (d(P)) be the maximal number of elements ofP which have the same length (which form an antichain). Further let
. The numbers
and
as well as all partially ordered sets for which these maxima are attained are determined. 相似文献
30.