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981.
Robert I. Ellis Julian F. Tyson 《Spectrochimica Acta Part B: Atomic Spectroscopy》1996,51(14):1859-1866
The possible benefits of the addition of an anionic surfactant, didodecyldimethylammonium bromide, in the determination of arsenic, by flow injection hydride generation atomic absorption spectrometry using a flame-heated quartz tube atomizer, were studied in the light of previous reports concerning the effects of surfactants on chemical vapor generation procedures. Concentrations of arsenic between 5 and 30 μg l−1 were used. Calibrations in the presence and absence of the surfactant in the sample solution were not significantly different, either for the case where vesicles were formed in the presence of the analyte or where they were preformed in the surfactant solution and then added to the analyte. The surfactant had no effect on recoveries in the presence of copper, nickel or bismuth. The addition of the surfactant to the acid carrier and/or borohydride streams had no effect. It is proposed that there may be a greater role for surfactants in the improvement of the processes by which the hydride is transferred to the bulk gas phase than has been attributed in previous reports on this subject. 相似文献
982.
Carol A. Ellis Edward R. T. Tiekink Julio Zukerman-Schpector 《Journal of chemical crystallography》2008,38(7):513-517
Abstract The title organic salt comprises a (E)-4-[2-(4-hydroxyphenyl)vinyl]-1-methylpyridinium cation, a 3-nitro-phenoxide anion and a solvent water molecule of crystallisation.
The anions and water molecules aggregate to form supramolecular chains facilitated by charge-assisted O–H···O hydrogen bonds
and these form layers which are interspersed by layers of cations. Interactions between layers include O–H···O hydrogen bonding,
as well as C–H···O and C–H···π contacts; π···π and C–H···O contacts are found within layers of cations. The compound crystallizes
in the monoclinic space group P21/n with a = 15.018(7) ?, b = 7.328(2) ?, c = 17.571(7) ?, β = 112.342(15)°, and Z = 4.
Index Abstract A layer structure comprising alternating anions/water molecules and cations associated via charge-assisted O–H···O hydrogen
bonding as well as C–H···O, C–H···π and π···π contacts is found in (II)
. 相似文献
983.
Matthew T. Richers Stefan Passlick Hitesh Agarwal Graham C. R. Ellis‐Davies 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12214-12218
We have developed a caged neurotransmitter using an extended π‐electron chromophore for efficient multiphoton uncaging on living neurons. Widely studied in a chemical context, such chromophores are inherently bioincompatible due to their highly lipophilic character. Attachment of two polycarboxylate dendrimers, a method we call “cloaking”, to a bisstyrylthiophene (or BIST) core effectively transformed the chromophore into a water‐soluble optical probe, whilst maintaining the high two‐photon absorption of over 500 GM. Importantly, the cloaked caged compound was biologically inert at the high concentrations required for multiphoton chemical physiology. Thus, in contrast to non‐cloaked BIST compounds, the BIST‐caged neurotransmitter can be safely delivered onto neurons in acutely isolated brain slices, thereby enabling high‐resolution two‐photon uncaging without any side effects. We expect that our cloaking method will enable the development of new classes of cell‐compatible photolabile probes using a wide variety of extended π‐electron caging chromophores. 相似文献
984.
Benjamin E. Kucera Christopher J. Roberts Victor G. Young William W. Brennessel John E. Ellis 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(9):1259-1265
Treatment of bis(mesitylene)niobium(0) with 6–7 equivalents of 2,6‐dimethylphenyl isocyanide (CNXyl) affords two products with the empirical formula Nb(CNXyl)n (n = 7 or 6), which have been shown to be the diamagnetic dimers bis[μ‐N,N′,N′′,N′′′‐tetrakis(2,6‐dimethylphenyl)squaramidinato(2?)]bis[pentakis(2,6‐dimethylphenyl isocyanide)niobium(I)], [Nb2(C9H9N)10(C36H36N4)] or [Nb(CNXyl)5]2[μ‐C4(NXyl)4]·xSolvent, 1 , and bis[μ‐N,N′,N′′,N′′′‐tetrakis(2,6‐dimethylphenyl)squaramidinato(2?)]bis[tetrakis(2,6‐dimethylphenyl isocyanide)niobium(I)] tetrahydrofuran trisolvate, [Nb2(C9H9N)8(C36H36N4)]·3C4H8O or [Nb(CNXyl)4]2[μ‐C4(NXyl)4]·3THF (THF = tetrahydrofuran), 2 . Each contains NbI bound to either five or four terminal isocyanides, respectively, and to an unprecedented bridging tetraarylsquaramidinate(2?) unit, coordinated as a bidentate ligand to each niobium center, symmetrically due to the crystallographic inversion center that coincides with the centroid of the central C4 unit. Thus, in the presence of CNXyl, the bis(mesitylene)niobium(0) is oxidized to niobium(I), resulting in the facile loss of both mesitylene groups and the reductive coupling of two CNXyl groups per niobium to provide the first examples of tetraarylsquaramidinate(2?) ligands, [cyclo‐C4N4Ar4]2?, coordinated to metals. In contrast, bis(mesitylene)niobium(0) reacts with the more crowded 2,6‐diisopropylphenyl isocyanide (CNDipp) to afford the paramagnetic monomer hexakis(2,6‐diisopropylphenyl isocyanide)niobium(0), [Nb(C13H17N)6] or Nb(CNDipp)6, 3 , the first zero‐valent niobium isocyanide analog of the highly unstable Nb(CO)6, which is presently only known to exist in an argon matrix at 4.2 K. 相似文献
985.
The properties of nanoparticles are often different from those of larger grains of the same solid material because of their very large specific surface area. This enables many novel applications, but properties such as agglomeration can also hinder their potential use. By creating nanostructured particles one can take optimum benefit from the desired properties while minimizing the adverse effects. We aim at developing high-precision routes for scalable production of nanostructured particles. Two gas-phase synthesis routes are explored. The first one - covering nanoparticles with a continuous layer - is carried out using atomic layer deposition in a fluidized bed. Through fluidization, the full surface area of the nanoparticles becomes available. With this process, particles can be coated with an ultra-thin film of constant and well-tunable thickness. For the second route - attaching nanoparticles to larger particles - a novel approach using electrostatic forces is demonstrated. The micron-sized particles are charged with one polarity using tribocharging. Using electrospraying, a spray of charged nanoparticles with opposite polarity is generated. Their charge prevents agglomeration, while it enhances efficient deposition at the surface of the host particle. While the proposed processes offer good potential for scale-up, further work is needed to realize large-scale processes. 相似文献
986.
Alba L. Montoya Elisa G. Carvajal Uriel Ortega-Rodriguez Igor L. Estevao Roger A. Ashmus Sohan R. Jankuru Susana Portillo Cameron C. Ellis Colin D. Knight Julio Alonso-Padilla Luis Izquierdo Maria-Jesus Pinazo Joaquim Gascon Veronica Suarez Douglas M. Watts Iliana R. Malo Janine M. Ramsey Belkisyol Alarcn De Noya Oscar Noya Igor C. Almeida Katja Michael 《Molecules (Basel, Switzerland)》2022,27(17)
Chagas disease (CD) is caused by the parasite Trypanosoma cruzi and affects 6–7 million people worldwide. The diagnosis is still challenging, due to extensive parasite diversity encompassing seven genotypes (TcI-VI and Tcbat) with diverse ecoepidemiological, biological, and pathological traits. Chemotherapeutic intervention is usually effective but associated with severe adverse events. The development of safer, more effective therapies is hampered by the lack of biomarker(s) (BMKs) for the early assessment of therapeutic outcomes. The mammal-dwelling trypomastigote parasite stage expresses glycosylphosphatidylinositol-anchored mucins (tGPI-MUC), whose O-glycans are mostly branched with terminal, nonreducing α-galactopyranosyl (α-Gal) glycotopes. These are absent in humans, and thus highly immunogenic and inducers of specific CD anti-α-Gal antibodies. In search for α-Gal-based BMKs, here we describe the synthesis of neoglycoprotein NGP11b, comprised of a carrier protein decorated with the branched trisaccharide Galα(1,2)[Galα(1,6)]Galβ. By chemiluminescent immunoassay using sera/plasma from chronic CD (CCD) patients from Venezuela and Mexico and healthy controls, NGP11b exhibited sensitivity and specificity similar to that of tGPI-MUC from genotype TcI, predominant in those countries. Preliminary evaluation of CCD patients subjected to chemotherapy showed a significant reduction in anti-α-Gal antibody reactivity to NGP11b. Our data indicated that NGP11b is a potential BMK for diagnosis and treatment assessment in CCD patients. 相似文献
987.
W. Kaczkowski W. v. Bergen Ellis Clayton A. G. Green A. Yeoman J. R. Jones F. G. C. Stephens G. A. Haley und K. Breuer 《Fresenius' Journal of Analytical Chemistry》1942,124(7-8):317-320
Ohne Zusammenfassung 相似文献
988.
989.
E. V. Jones J. R. Stubbs G. D. Elsdon E. B. Grayson W. F. Elvidge Gl. Leavell N. R. Ellis und F. W. Richardson 《Fresenius' Journal of Analytical Chemistry》1935,101(3-4):120-122
Ohne Zusammenfassung 相似文献
990.
R. Intont Ch. Thom K. B. Raper F. W. Tanner A. Schneider F. Challenger C. Higginbottom L. Ellis J. B. Ramsey J. G. Blann I. M. Kolthoff N. H. Furman W. C. Bray E. Azzarello F. Abramo Raymond Emil J. Fischer E. Jaffe und P. E. Winkler 《Fresenius' Journal of Analytical Chemistry》1935,100(7-8):284-289
Ohne Zusammenfassung 相似文献