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141.
Aihara H Alston-Garnjost M Avery RE Barbaro-Galtieri A Barker AR Barnes AV Barnett BA Bauer DA Bengtsson H Bintinger DL Blumenfeld BJ Bobbink GJ Bross AD Buchanan CD Buijs A Cain MP Caldwell DO Chamberlain O Chien C Clark AR Cowan GD Crane DA Dahl OI Derby KA Eastman JJ Eberhard PH Eisner AM Enomoto R Erné FC Fujii T Gabioud B Gary JW Gorn W Hauptman JM Hofmann W Huth JE Hylen J Joshi UP Kamae T Kaye HS Kees KH Kenney RW Kerth LT Ko W Koda RI Kofler RR Kwong KK Lander RL Langeveld WG Layter JG 《Physical review letters》1986,57(4):404-407
142.
Corbellini F Fiammengo R Timmerman P Crego-Calama M Versluis K Heck AJ Luyten I Reinhoudt DN 《Journal of the American Chemical Society》2002,124(23):6569-6575
Herein we report the formation and characterization of a novel type of capsules resulting from the self-association between oppositely charged complementary building blocks in MeOH/H2O. The assembly is based on the interaction between tetraamidinium calix[4]arenes 1a-d and tetrasulfonato calix[4]arene 2. Evidence for the formation of the expected 1:1 assemblies is provided by proton NMR, ESI-MS, and ITC. The association process is fast on the NMR time scale and strongly entropy driven, with association constants in the range of 10(6) M-1. The system 1a.2 shows binding affinity toward acetylcholine, tetramethylammonium, and N-methylquinuclidinium cations. 相似文献
143.
DirkJ.A. DeRidder Kees Goubitz Henk Schenk Bert Krijnen JanW. Verhoeven 《Helvetica chimica acta》2003,86(3):799-811
The crystal structures of five N‐arylpiperidin‐4‐one derivatives 2P2, 3P2, 5P2, 1P3 , and 2P3 are presented (Fig. 2 and Tables 1–5) and discussed together with the derivatives 1P2 and 4P2 published previously. In all but one structure, 1P2 , the aryl group is in an equatorial position. The piperidine ring adopts a normal chair conformation. In 1P2 , the piperidine ring central C? C bonds are significantly elongated, which is consistent with the idea that through‐bond interaction is more pronounced in the axial conformation. Through‐bond interaction also influences the pyramidalization at the piperidine C(4)‐atom in such a way that a strong interaction is directing the ethylene C‐atom C(9) into the axial direction. 相似文献
144.
Frank van Mourik Kees J. Visscher Jan M. Mulder Rienk van Grondelle 《Photochemistry and photobiology》1993,57(1):19-23
–Triplet-minus-singlet (T-S) spectra and singlet-triplet annihilation was measured on Rhodospirillum rub-rum chromatophores at low temperatures (4–77K). The T-S spectrum of the LH-1 antenna was dependent on the wavelength of excitation and thus indicative of site-inhomogeneous broadening. The data cannot be understood adequately using the two pigment pool model (B880 + B896) but, in contrast, support a model for LH-1, in which the spectral properties are determined by site-inhomogeneous broadening. Consequently, the 4 K antenna domain for singlet-triplet annihilation in LH-1 is rather small. If the temperature is raised to 77 K the annihilation domain increases, and a fit of the fluorescence quenching and triplet yield data suggests that at 77 K the connectivity is between the extreme cases of the “lake” and the isolated “puddles” models. The implications of the observed antenna inhomogeneity on low temperature annihilation and fluorescence measurements are discussed. 相似文献
145.
Summary Reaction of (PPh3)2Cl2CoII with TlC5H5 gave the new (
5-C5H5)(PPh3)ClCoII complex. This complex reacted with Ag(RN3R) or Cu(RN3R) (R=p-MeC6H4,p-ClC6H4 or 3,5-Cl2C6H3) to give the novel compounds (
5-C5H5)(PPh3)(RN3R)CoII, with a spin state of one half, which are representatives of the very small class of paramagnetic monocyclopentadienyl transition metal complexes. The structural conclusions are based on comparison with the isostructural [
5-C5H5)(PPh3)(RN3R)CoIII]PF6 complex, on the i.r. spectra and on the observed redox behaviour. The e.p.r. spectra are reported, but are not well enough resolved for the determination of the hyperfine interactions. The orbital scheme of the new complex is discussed in terms of a distorted octahedral crystal field in relation to the series of isostructural (
5-C5H5)(PPh3)(RN3R)MII (M = Fe, Co or Ni) complexes. 相似文献
146.
The formation of carbon tetrachloride‐benzene charge transfer complex was confirmed by UV and NMR spectrometric studies. A change in UV spectrum of benzene is observed upon addition of carbon tetrachloride. Whereas the appearance of new bands supports the formation of charge transfer complex. NMR study shows that, chemical shift of benzene pmr signal depends on the CCl4‐C6H6 molar ratio. This observation is another criterion for the formation of benzene‐carbon tetrachloride charge transfer complex. Job's Continuous Variation method indicates that a 2:1 CCl4‐C6H6 charge transfer complex (2:1 CTC) is formed. The association constants (K2:1) of (2:1 CTC) was found to be 0.0197 M?2. The maximum concentration of (2:1 CTC) was found to be in samples with 2:1 CCl4‐C6H6 molar ratio (33% benzene mole). On the other hand the maximum yield of chlorobenzene was obtained, also, upon radiolysis of CCl4‐C6H6 samples at a 2:1 molar ratio (33% benzene mole). Therefore, it could be concluded that (2:1 CTC) participates in the formation of chlorobenzene upon radiolysis of the benzene‐carbon tetrachloride system. This conclusion was supported by the dependence of the chlorobenzene yield of a γ‐irradiated carbon tetrachloride‐benzene system (2:1 molar ratio) on irradiation time according to a third order kinetic equation with a very good linearity (R2 = 0.9977). Accordingly, the rate constant for the chlorobenzene formation under this condition was found to be ≈ 5.5 × 10?7 L2.mol?2.h?1. We propose a radiation chemical mechanism in which the 2:1 CTC plays a role in the formation of chlorobenzene. 相似文献
147.
Kees de Jager 《Progress in Particle and Nuclear Physics》2008,61(1):311-324
Preliminary results of a selected few recent experiments at JLab are presented. 相似文献
148.
Systematic design of an autonomous platform for robotic weeding 总被引:3,自引:0,他引:3
Tijmen Bakker Kees Asselt van Joachim Müller Gerrit Straten van 《Journal of Terramechanics》2010,47(2):63-73
The systematic design of an autonomous platform for robotic weeding research in arable farming is described. The long term objective of the project is the replacement of hand weeding in organic farming by a device working autonomously at field level. The distinguishing feature of the described design procedure is the use of a structured design approach, which forces the designer to systematically review and compare alternative solution options, thus preventing the selection of solutions based on prejudice or belief. The result of the design is a versatile research vehicle with a diesel engine, hydraulic transmission, four-wheel drive and four-wheel steering. The robustness of the vehicle and the open software architecture permit the investigation of a wide spectrum of research options for intra-row weed detection and weeding actuators. 相似文献
149.
Christoph Dorn Selina Schießer Beatrix Wulkersdorfer Florian Hitzenbichler Martin G. Kees Markus Zeitlinger 《Biomedical chromatography : BMC》2020,34(6):e4820
Pharmacokinetic/pharmacodynamic indices of anti-infective drugs should be referenced to free drug concentrations. In the present study, clindamycin, flucloxacillin and tedizolid have been determined in human plasma by HPLC–UV. The drugs were separated isocratically within 3–6 min on a C18 column using mixtures of phosphate buffer–acetonitrile of pH 7.1–7.2. Sample treatment for the determination of total drug concentrations in plasma included extraction/back-extraction (clindamycin) or protein precipitation (flucloxacillin, tedizolid). The free drug concentrations were determined after ultrafiltration. An ultrafiltration device with a membrane consisting of regenerated cellulose proved to be suitable for all drugs. Maintaining a physiological pH was crucial for clindamycin, whereas maintaining body temperature was essential for tedizolid. The methods were applied to the analysis of total and free drug concentrations in clinical samples and were sufficiently sensitive for pharmacokinetic studies and therapeutic drug monitoring. 相似文献
150.