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191.
Gisbert zu Putlitz 《Zeitschrift für Physik A Hadrons and Nuclei》1963,175(5):543-552
In order to determine the electric quadrupole moment of Sr87 (I= 9/2) the hyperfine structure-splitting of the 5s5p 3 P 1-state of the SrI-spectra was investigated by optical double resonance. By detection of high frequency transitions (ΔF=±1,Δm F=0,±1) in an external magnetic fieldH 0≈0 one obtains the hyperfine structure separations asv F=11/2?F=9/2=1463·149 (6) Mc/sec andv F=9/2?F=7/2=1130·264 (6) Mc/sec. From these frequencies one calculates the magnetic hyperfine structure-splitting constantA=?260·084 (2) Mc/sec and the electric quadrupole interaction constantB=?35·658 (6) Mc/sec. B leads to an electric quadrupole moment ofQ(Sr87)=+0·36 (3)·10?24 cm2. 相似文献
192.
Gisbert Wüstholz 《manuscripta mathematica》1977,20(4):335-354
In this note we shall carry on further the simultaneous approximation of a, b and exp(bloga). In a recent paper BUNDSCHUH [2] proved a theorem which appears to be a sharpening of a theorem of SCHNEIDER [10]. But there is an error in the proof. We shall show, that under a supplementary condition, the theorem of BUNDSCHUH remains valid and as well, get an improvement to this theorem. We further give some results on linear forms in logarithms of two U-numbers with algebraic coefficients. 相似文献
193.
Koichi Yamada Manfred Winnewisser Gisbert Winnewisser L.B Szalanski M.C.L Gerry 《Journal of Molecular Spectroscopy》1980,79(2):295-313
The rotational spectrum of isothiocyanic acid was measured for the isotopically enriched species H15NCS and HN13CS as well as HNC34S in natural abundance. In the frequency range from 8 to 240 GHz the a-type R-branch transitions were measured for all three isotopic species. The qQ1 transitions were identified in the microwave region for H15NCS and HN13CS. The rotational and centrifugal distortion constants were determined using Watson's Hamiltonian in the S reduction, extended empirically to higher order terms in the angular momentum. The molecular structure of isothiocyanic acid was reevaluated using a modified substitution method and the NCS chain was found to be bent: , , , ∠HNC = 131.7°, and ∠NCS = 173.8°. The molecule has the trans conformation. 相似文献
194.
195.
Cnovas M. J. Gisbert M. J. Klatte D. Parra J. 《Journal of Optimization Theory and Applications》2022,193(1):280-299
Journal of Optimization Theory and Applications - In this paper, we use a geometrical approach to sharpen a lower bound given in [5] for the Lipschitz modulus of the optimal value of (finite)... 相似文献
196.
A virtual screening procedure based on a topological pharmacophore similarity metric and self-organizing maps (SOM) was developed and applied to optimizing combinatorial products functioning as P(1) purinergic receptor antagonists. The target was the human A(2A) receptor. A SOM was developed using a set of biologically tested molecules to establish a preliminary structure-activity relationship. A combinatorial library design was performed by projecting virtually assembled new molecules onto the SOM. A small focused library of 17 selected combinatorial products was synthesized and tested. On average, the designed structures yielded a 3-fold smaller binding constant ( approximately 33 vs approximately 100 nM) and 3.5-fold higher selectivity (50 vs 14) than the initial library. The most selective compound obtained revealed a 121-fold relative selectivity for A(2A) with K(i) (A(2A)) = 2.4 nM, and K(i) (A(1)) = 292 nM. This result demonstrates that it was possible to design a small, activity-enriched focused library with an improved property profile using the SOM virtual screening approach. The strategy might be particularly useful in projects in which structure-based design cannot be applied because of a lack of receptor structure information, for example, in the many projects aiming at finding new GPCR modulators. 相似文献
197.
A series of polyureas were synthesized from amino terminated polydimethylsiloxane oligomers, diamine comonomers, and various
diisocyanates. These polymers were characterized by nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and size
exclusion chromatography (SEC). The gelation behavior in silicone fluids such as dimethylcyclosiloxanes was investigated.
The influence of the structure of the hard segment on the gelation properties was evaluated. 相似文献
198.
Harry Schäfer Margit Gruner Gisbert Großmann Karl Gewald 《Monatshefte für Chemie / Chemical Monthly》1991,122(11):959-966
Summary The title compounds were synthesized by reaction of nitroketene aminals with -chlorovinylcarbonyl compounds. The chloromethylene malononitriles1 react with nitromethylenimidazolin (2 a) and -benzimidazoles2 b to yield the 8-nitro-2,3-dihydroimidazo[1,2-a]pyridines3 and the 4-nitropyrido[1,2-a]-benzimidazoles6, both containing an amino group. Analogously, from the special 3-chloro-2-propeniminium salt7 and2 a the imidazopyridine derivative9 was formed. The 3-aryl-3-chloro-2-propeniminium salts10 were converted into the nitro-dihydroimidazo[1,2-a]pyridines11 and the pyrido[1,2-a]benzimidazole12 containing the aryl group by reaction with2 a and2 b, respectively. The structures were investigated by 2-dimensional1H/13C-NMR-spectroscopy. 相似文献
199.
Gisbert Puzicha Albert Lévai Günther Snatzke 《Monatshefte für Chemie / Chemical Monthly》1990,121(4):293-298
Summary Chiroptical properties of the title compounds have been studied. The influence of the substitution pattern of the aromatic ring and the configuration of the centre of chirality on the Cotton effects appearing in various wavelengths ranges are discussed.
Oxazepine und Thiazepine, 21. Mitt.: CD-Spektren optisch aktiver 2-Methyl-2,3-dihydro-1,5-benzothiazepin-4(5H)-one und verwandter 3-Phenylthio-buttersäure-Derivate
Zusammenfassung Die chiroptischen Eigenschaften der im Titel genannten Verbindungen wurden studiert. Der Einfluß des Substitutionsmusters des aromatischen Rings und der Konfiguration des Chiralitätszentrums auf die Cotton-Effekte, die in verschiedenen Wellenlängenbereichen auftreten, werden besprochen.相似文献
200.
Thirty b-type P, Q and R branch rotational transitions and nineteen a-type Q and R branch transitions have been detected and measured for the slightly asymmetric rotor molecule D14N3 in the frequency range from 8 to 340 GHz. The information obtained from the analysis of the observed frequencies are greatly improved values of the K-dependent parameters AO = 344746.589(64) MHz, and DK = 92.242(33) MHz, refined values for the rotational constants BO and CO, a complete set of quartic centrifugal distortion constants and several sextic distortion constants. Both a and b components of the electric dipole moment were determined giving a total dipole moment of μ = 1.76(5) debye. 相似文献