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991.
Arnaud Boreux Aubin Lambion Dominic Campeau Marina Sanita Ruben Coronel Olivier Riant Fabien Gagosz 《Tetrahedron》2018,74(38):5232-5239
The synthesis of fluorinated synthetic intermediates has become a field of intense research in organic chemistry. In this article, we report the application of a gold-catalyzed rearrangement to the synthesis of β-trifluoromethylated α,β-unsaturated ketones. The scope of the reaction, as well as the valorization of the products in subsequent transformations has been investigated. This study allowed for the preparation of various CF3-substituted enones and fluorinated Diels-Alder adducts from easily accessible starting materials. 相似文献
992.
Lyubov N. Sobenina Elena F. Sagitova Marina V. Markova Igor A. Ushakov Andrey V. Ivanov Boris A. Trofimov 《Tetrahedron letters》2018,59(45):4047-4049
Acylethynylpyrroles, available via the transition metal-free coupling of pyrroles with acylhaloacetylenes are readily annelated with propargylamine in a one-pot step-wise procedure: catalyst-free heating (60–65?°C, 6–16?h) in DMSO and then keeping for 2.5?h with CuI at the same temperature. The products are pyrrolyl-pyridines isolated in good to excellent yields (56–94%). It is experimentally shown that dehydrogenation of intermediate dihydropyridine moiety is not resulted from the oxidation with DMSO (Me2S was not detected) or air (argon blanket) and is likely associated with the CuI catalysis. 相似文献
993.
Ilyas S. Nizamov Andrey A. Yakovlev Ilnar D. Nizamov Dmitriy A. Terenzhev Kamil A. Ivshin Olga N. Kataeva Marina P. Shulaeva Oscar K. Pozdeev Elvira S. Batyeva Rafael A. Cherkasov 《应用有机金属化学》2018,32(5)
Chiral S‐tributylstannyl dithiophosphates and dithiophosphonates were obtained by the reactions of optically active dithiophosphoric and dithiophosphonic acids containing (S)‐(–)‐menthyl and (R)‐(+)‐menthyl substituents with gaseous ammonia and tributyl chlorostannane. The reactions of chiral ammonium dithiophosphate containing (1R)‐endo‐(+)‐fenchyl substituent with tributyl chlorostannane or tetrachlorostannane result in corresponding S‐tributylstannyl dithiophosphate or tetrakis(dithiophosphato)stannane. Molecular structure of ammonium O,O‐di‐(–)‐menthyldithiophosphate was studied by X‐ray single crystal diffraction. Bactericidal activity of S‐tributylstannyl dithiophosphates was tested. 相似文献
994.
995.
Marina S. Fonar Yurij A. Simonov Alexander A. Dvorkin Tadeush I. Malinowsky Edward V. Ganin Sergej Kotlyar Vladimir F. Makarov 《Journal of inclusion phenomena and macrocyclic chemistry》1989,7(6):613-622
Both title complexes were prepared by reacting a methanol solution of the respective isomer of dicyclohexano-18-crown-6 (DCH18C6) with an aqueous solution of amidosulfuric acid. Crystals suitable for X-ray crystallography were obtained by recrystallization from methanol.Crystals of [cis-syn-cis-DCH18C6][NH2SO2OH·CH3OH] (1) are monoclinic, space groupP21ln,a = 21.700(8),b = 13.725(5),c = 9.118(6) Å, = 76.29(2) Å. Refinement led to a final conventionalR value of 0.065 for 2083 reflections. [Cis-anti -cis-DCH18C6][NH2SO2OH] (2) crystallizes in the orthorombic space groupPna21 with unit cell dimensionsa = 17.154(7),b = 16.051(7),c =8.630(5) Å. Refinement was terminated at anR value of 0.067 for 1936 reflections. 相似文献
996.
The closed-form shifting (CFS) algorithm is a simple mathematical methodology which determines the unique solution in the process of constructing master curves at selected reference temperature and pressure conditions. In a previous paper, the CFS algorithm has been fully described for monotonically increasing or monotonically decreasing functions only. This paper presents detailed steps of the generalized CFS methodology for non-monotonic functions, like the loss tangent. Performing shifting on the loss tangent, which does not require vertical shifting, is particularly important for materials which require vertical adjustment of dynamic viscoelastic functions, i.e., loss and storage moduli. Thus, based on horizontal shifting of the loss tangent, the CFS-based procedure of consecutive horizontal-vertical superposition for the storage modulus is proposed and analyzed. The analysis is done on the example of two synthetically generated non-monotonic tan delta segments and corresponding storage modulus segments in respect to different experimental parameters. It has been shown that the error brought by the shifting method into non-monotonic loss tangent and storage modulus master curves is twice smaller than the corresponding experimental noise level. 相似文献
997.
Alexander V. Yakimansky Stanislav V. Bushin Marina A. Bezrukova Alexey A. Lezov Alexander S. Gubarev Elena V. Lebedeva Lilija I. Akhmadeeva Anna N. Podseval'nikova Nikolaj V. Tsvetkov Guy Koeckelberghs Andre Persoons 《Journal of Polymer Science.Polymer Physics》2016,54(9):875-883
Conducting polymers demonstrate low solubility in organic solvents. Introducing aliphatic substituents into polymer chains improves their solubility, but may also lead to changes in conformational characteristics of macromolecules. In the present work, the studies of hydrodynamic properties and conformational characteristics of comb‐shaped poly(3‐hexylthiophene) with aliphatic side substituents were carried out in chloroform solutions. Conformational analysis of the studied macromolecules was performed for the first time using homologous series with a wide range of molecular weights of the polymers in dilute solutions. The hydrodynamic properties of these macromolecules were interpreted using the worm‐like spherocylinder model and the straight spherocylinder model. The projection of the monomer unit in the direction of the main polymer chain λ = 0.37 nm was determined experimentally. The following parameters of poly(3‐hexylthiophene) were characterized and quantified: equilibrium rigidity (Kuhn segment length) А = 6.7 nm and hydrodynamic diameter of a polymer chain d = 0.6 nm. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 875–883 相似文献
998.
999.
1000.
Igor Jerković Ani Radonić Marina Kranjac Marina Zekić Zvonimir Marijanović Senka Gudić Maja Kliškić 《Chemical Papers》2016,70(6):726-736
Headspace solid-phase micro-extraction (HS-SPME) and ultrasonic solvent extraction (USE) were used for red clover honey volatiles extraction. The extracts were analysed using gas chromatography and mass spectrometry (GC-MS). Lilac aldehyde isomers dominated in the headspace (individual range from 7.6 % to 21.4 %) followed by phenylacetaldehyde (10.1–31.2 %) and benzaldehyde (7.0–15.7 %). Higher aliphatic alcohols and hydrocarbons were the predominant constituents of the honey extracts. The honey and its extracts exhibited rather weak anti-radical activity (DPPH assay) and total antioxidant activity (FRAP assay). On the other hand, the honey’s inhibitive properties towards the corrosion of AA 2017A alloy in NaCl solution (potentiodynamic polarisation and potentiostatic pulse measurements) revealed the honey to be a very good anodic inhibitor (efficiency up to 76 %) while the honey extracts (USE) showed better inhibition efficacy. 相似文献