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101.
We report the pressure-induced superconductivity in the noncentrosymmetric heavy-fermion CeRhSi3. The superconductivity emerges above about 12 kbar even though the antiferromagnetic ordering persists. Furthermore, another anomaly is observed in the superconducting phase. The anomalous magnetic field-temperature phase diagram with a high upper critical field suggests that an unconventional superconductivity is realized in CeRhSi3. 相似文献
102.
103.
104.
The novel peptide bond formation previously reported in the reaction of glycine ester with Cu(II) ion in an anhydrous solvent, was examined using several kinds of optically active amino acid esters. Various reaction conditions were studied in detail for Phe-OEt. From Phe-OEt, Ala-OMe, Leu-OMe, Trp-OMe, Ser-OMe, and Met-OMe, the expected dipeptide esters with the same amino acid components were obtained without racemization. Asp(OEt)-OEt, and Glu(OMe)-OMe gave only optically active α-dipeptide esters. No formation of dipeptide esters was observed with Ile-OMe, Cys-OMe, His-OMe, and Pro-OEt. However, Lys-OMe, and Orn-OMe afforded optically active lactam derivatives. Some explanations of these abnormal observations have been given.Attempts to prepare di- and tri-peptide esters carrying different kinds of amino acid units were also studied. 相似文献
105.
106.
The synthetic procedures of the title compound (2), a protected form of carzinophilin (1), were developed. While efforts toward the total synthesis of 1 failed, comparison of the 1H NMR spectra of 2 and some other related compounds with that of 1 provided definite support for the absolute stereochemistry of 1 which has a complicated history regarding its structure. 相似文献
107.
With an aim to overcome several inefficient aspects of ordinary methods of preparing optically active compounds, we have developed a new method which recommends utilization of symmetrically functionalized meso-compounds in place of racemic compounds.As shown in Scheme 1, when the mesa-compound (I) is monofunctionalized by an optically active functional group (A) and each of the formed diastereomers (II and III) is subjected to further chemical elaborations including protective group transposition, it is theoretically possible to convert the total amount of the starting material (I) into the requisite optically pure product (VI or VII) by selecting synthetic schemes.By employing this novel concept, two structural types of the prostaglandin intermediates ((?)- and ( + )-2a,b) have been prepared from the meso-diols (1a, b) by way of the two diastereomeric monoesters (13a, b and 14a, b) which are produced by the reactions of 1a, b with N-mesyl- and N-phthaloyl-(S)-phenylalanyl chloride (3a, b). 相似文献
108.
We give a finite-dimensional and geometric construction of a Chern character for twisted K-theory, introducing a notion of connection on a twisted vectorial bundle which can be considered as a finite-dimensional
approximation of a twisted family of Fredholm operators. Our construction is applicable to the case of any classes giving
the twisting, and agrees with the Chern character of bundle gerbe modules in the case of torsion classes. 相似文献
109.
This paper is a revised version of my previous paper [4]. Main purpose is to give a right proof for non-archimedean Hartogs
theorem(Stawski’s theorem) in case when the value group of the field K is discrete. 相似文献
110.
Takaya Terashima Makoto Ouchi Tsuyoshi Ando Mitsuo Sawamoto 《Journal of polymer science. Part A, Polymer chemistry》2010,48(2):373-379
Thermoregulated phase‐transfer catalysis for the transfer hydrogenation of 2‐octanone in 2‐propanol/H2O biphasic media was achieved with ruthenium‐bearing microgel‐core star polymers with amphiphilic, thermosensitive poly(ethylene glycol) (PEG) arms [Ru(II)‐PEG star], which were directly prepared by the ruthenium‐catalyzed living radical polymerization in conjunction with a phosphine ligand‐carrying styrene derivative. The star polymers were first placed in the aqueous (lower) layer at room temperature and immediately moved into the organic (upper) layer at 100 °C, and once again, moved down to the aqueous layer (lower) upon cooling the solution to room temperature. The Ru(II)‐PEG star catalyst was clearly superior to the original Ru(II) catalyst and related non‐microgel catalysts [Ru(II)‐PEG block] in terms of activity and recovery/recycle, due to the unique designer structure of the microgel‐core star polymers. Other substrates (less hydrophobic alkyl ketones and aromatic ketone) were also efficiently hydrogenated into the corresponding sec‐alcohols with the star catalyst in aqueous media. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 373–379, 2010 相似文献