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101.
102.
We prove that the universal covering of a complete locally symmetric normal metric contact pair manifold with decomposable ? is a Calabi‐Eckmann manifold or the Riemannian product of a sphere and . We show that a complete, simply connected, normal metric contact pair manifold with decomposable ?, such that the foliation induced by the vertical subbundle is regular and reflections in the integral submanifolds of the vertical subbundle are isometries, is the product of globally ?‐symmetric spaces or the product of a globally ?‐symmetric space and . Moreover in the first case the manifold fibers over a locally symmetric space endowed with a symplectic pair. 相似文献
103.
104.
Gianluca Ambrosi Mauro Micheloni Daniele Paderni Mauro Formica 《Supramolecular chemistry》2020,32(2):139-149
ABSTRACTThe new macrocyclic ligand L (28,29-dimethoxy-27-oxa-8,11,14,17,25,26-hexaazatetracyclo[22.2.1.1(2,6).1(19,23)]nonacosa-2,4,6(28),19,21,23(29),24,26(1)-octaene) has been synthesised. It contains a tetramine chain and the 2,5-bis(2-methoxy-3-metyl-phenyl)-1,3,4-oxadiazole (PPD-OMe) chromophore, acting as coordinating and sensing units, respectively.The fluorescent emission of L depends on the pH being highly fluorescent at pH = 2 and not emitting from pH >10. The studies highlighted that L is a PET mediated emitting chemosensor, being the PET effect regulated by the degree of the tetraamine protonation.L coordinates metal ions (Cu(II), Zn(II) and Cd(II)) in water giving rise to an OFF-ON fluorescent response for the presence of Zn(II) ion thus signalling its presence in the medium. This response is particularly notable at pH = 9 allowing to extend the Zn(II) sensing also in the alkaline pH field. 相似文献
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107.
Lucia Giorgetti Gianluca Giorgi Edoardo Cherubini Pier Giovanni Gervasi Clara Maria Della Croce Vincenzo Longo 《Natural product research》2018,32(14):1617-1626
We report the spectrophotometric determination of total polyphenols, flavonoids, glucosinolates and antioxidant activity in seeds, seedlings and leaves of Tuscan black kale. The highest content of phytochemicals was observed in 10 days sprouts and antioxidant activity was maximum in 2, 4 days seedlings. Identification and characterisation of phytochemicals were performed by mass spectrometry (MS), high resolution and tandem MS with electrospray ionisation mode. Low-molecular-weight metabolites were evidenced in seeds while metabolites at high m/z range were detected in cotyledons and leaves. MS spectra evidenced different phenolic compounds (flavonoid caffeoyl glucose, hydroxycinnamic acid sinapine) and glucosinolates (glucoerucin, glucobrassicin and glucoraphanin) in function of developmental stage; galactolipids ω3 and ω6 were observed in leaves. Identification of stages with the highest phytochemicals content encourages the consumption of black kale sprouts and young leaves. Our research can support food and pharmaceutical industries for production of health promoting products from black kale. 相似文献
108.
Gabriele Bocelli Gianluca Calestani Corrado Rizzoli 《Journal of chemical crystallography》1990,20(3):217-221
Crystals of the title compound are monoclinic (C26H25NO): space groupP21/c,a=16.565(3),b=10.328(2),c=12.621(3) Å,=104.02(3)°. The structure was solved by direct methods and refined by block-matrix least-squares to giveR=0.056 andR
w
=0.061 for 1613 reflections above 2(I). The amide moiety is tilted by 19.3(2)° with respect to the mean aromatic ring plane. The two othergem phenyl rings subtend a dihedral angle of 112.2(4)° to each other. The molecules are joined in the solid by N-HO hydrogen bonds. 相似文献
109.
Attanasi OA Favi G Filippone P Giorgi G Mantellini F Moscatelli G Spinelli D 《Organic letters》2008,10(10):1983-1986
The versatility of the Mukaiyama-Michael-type addition/heterocyclization of Danishefsky's diene with 1,2-diaza-1,3-butadienes was applied to the synthesis of both 4 H-1-aminopyrroles and 4,5 H-pyrazoles. Thus, the same reagents furnished different types of highly functionalized azaheterocycles essentially depending on their structure: as a matter of fact, R1 = COOR or CONR 2 differently affects the acidity of the proton at the adjacent carbon. An unexpected formation of 5 H-1-aminopyrroles from the reactions carried out in water was also observed. 相似文献
110.
Alfonso Pedone Gianluca Malavasi Alastair N. Cormack Ulderico Segre M. Cristina Menziani 《Theoretical chemistry accounts》2008,120(4-6):557-564
This paper shows recent progresses in the field of computer simulations of inorganic glasses. Molecular dynamics simulations and energy minimization methods have been applied to calculate the elastic and transport properties of alkali silicate glasses of compositions xM2O · (100 ? x)SiO2 (with x = 0, 10, 15, 20, 25, 30 % mol for M = Li, Na and K) and of a soda-lime glass with composition 15Na2O · 10CaO · 75SiO2, which has been employed to ascertain the effect of the replacement of CaO for Na2O. The excellent agreement of the computed results with the experimental data highlights the important predictive and interpretative role reached by computer simulations techniques. 相似文献