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131.
A primal transportation algorithm is devised via post-optimization on the costs of a modified problem. The procedure involves altering the costs corresponding to the basic cells of the initial (primal feasible) solution so that it is dual feasible as well. The altered costs are then successively restored to their true values with appropriate changes in the optimal solution by the application of cell or area cost operators discussed elsewhere. The cell cost operator algorithm converges to optimum within (2T – 1) steps for primal nondegenerate transportation problems and [(2T + 1) min (m, n)] – 1 steps for primal degenerate transportation problems, whereT is the sum of the (integer) warehouse availabilities (also the sum of the (integer) market requirements) andm andn denote the number of warehouses and markets respectively. For the area cost operator algorithm the corresponding bounds on the number of steps areT and (T + 1) min (m, n) respectively.This report was prepared as part of the activities of the Management Sciences Research Group, Carnegie—Mellon University, under Contract N00014-67-A-0314-0007 NR 047-048 with the U.S. Office of Naval Research. 相似文献
132.
We investigate then limit of then-vector model single-spin and pairspin correlation functions. In this limit we show that the correlation functions become those of the corresponding spherical model. 相似文献
133.
Gurfinkel M Thompson AB Ralston W Troy TL Moore AL Moore TA Gust JD Tatman D Reynolds JS Muggenburg B Nikula K Pandey R Mayer RH Hawrysz DJ Sevick-Muraca EM 《Photochemistry and photobiology》2000,72(1):94-102
We present in vivo fluorescent, near-infrared (NIR), reflectance images of indocyanine green (ICG) and carotene-conjugated 2-devinyl-2-(1-hexyloxyethyl) pyropheophorbide (HPPH-car) to discriminate spontaneous canine adenocarcinoma from normal mammary tissue. Following intravenous administration of 1.0 mg kg-1 ICG or 0.3 mg kg-1 HPPH-car into the canine, a 25 mW, 778 nm or 70 mW, 660 nm laser diode beam, expanded by a diverging lens to approximately 4 cm in diameter, illuminated the surface of the mammary tissue. Successfully propagating to the tissue surface, ICG or HPPH-car fluorescence generated from within the tissue was collected by an image-intensified, charge-coupled device camera fitted with an 830 or 710 nm bandpass interference filter. Upon collecting time-dependent fluorescence images at the tissue surface overlying both normal and diseased tissue volumes, and fitting these images to a pharmacokinetic model describing the uptake (wash-in) and release (wash-out) of fluorescent dye, the pharmacokinetics of fluorescent dye was spatially determined. Mapping the fluorescence intensity owing to ICG indicates that the dye acts as a blood pool or blood persistent agent, for the model parameters show no difference in the ICG uptake rates between normal and diseased tissue regions. The wash-out of ICG was delayed for up to 72 h after intravenous injection in tissue volumes associated with disease, because ICG fluorescence was still detected in the diseased tissue 72 h after injection. In contrast, HPPH-car pharmacokinetics illustrated active uptake into diseased tissues, perhaps owing to the overexpression of LDL receptors associated with the malignant cells. HPPH-car fluorescence was not discernable after 24 h. This work illustrates the ability to monitor the pharmacokinetic delivery of NIR fluorescent dyes within tissue volumes as great as 0.5-1 cm from the tissue surface in order to differentiate normal from diseased tissue volumes on the basis of parameters obtained from the pharmacokinetic models. 相似文献
134.
135.
Polymer films containing a sodium or potassium ion-selective exchanger were coated onto platinum wire and incorporated into a potentiometric arrangement. Comparative results obtained by utilizing different measuring devices, one a conventional pH-meter and the other a field-effect transistor (FET) in series with an electrometer, are discussed. The linear range of either system is comparable with that of other electrochemical techniques. Possible applications of such a device are described. 相似文献
136.
Vonderheide AP Meija J Tepperman K Puga A Pinhas AR States JC Caruso JA 《Journal of chromatography. A》2004,1024(1-2):129-137
High-performance chelation ion chromatography (HPCIC) was employed to retain cationic Cr(III) on an anion-exchange column and hence allow the separation of the two most prevalent forms of chromium, Cr(II) and Cr(VI). A mobile phase of nitric acid was utilized at pH = 1.5; additionally, 2,6-pyridinedicarboxylic acid was used at a concentration of 6 mM. Additives with different structural characteristics were used in an effort to elucidate retention mechanisms. Inductively-coupled plasma mass spectrometry was used for chromium detection. A collision cell was utilized to reduce chloride-based polyatomic ions that may interfere with the detection of Cr(III), and a detection limit study yielded levels in the low part-per-billion range. The newly developed method was applied to the chromatographic analysis of samples of an incubation medium containing Cr(VI) incubated with cell nuclei. 相似文献
137.
Lipid membranes composed of phosphatidyl choline and cholesterol were interfaced to polyacrylamine hydrogen by Langmuir—Blodgett thin-film deposition. The extent of lipid adsorption to the gel surface was critically dependent on the hydration of the polymer as determined by contact angle measurements. Some electrochemical transducers incorporating the deposited membrane/gel structure responded positively to phloretin and valinomycin. Limitations to the construction of this device are discussed. 相似文献
138.
Susan A. Bourne Katherine De Villiers Timothy J. Egan 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):o53-o57
The structures of three compounds with potential antimalarial activity are reported. In N,N‐diethyl‐N′‐(7‐iodoquinolin‐4‐yl)ethane‐1,2‐diamine, C15H20IN3, (I), the molecules are linked into ribbons by N—H⋯N and C—H⋯N hydrogen bonds. In N‐(7‐bromoquinolin‐4‐yl)‐N′,N′‐diethylethane‐1,2‐diamine dihydrate, C15H20BrN3·2H2O, (II), two aminoquinoline molecules and four water molecules form an R54(13) hydrogen‐bonded ring which links to its neighbours to form a T5(2) one‐dimensional infinite tape with pendant hydrogen bonds to the aminoquinolines. The phosphate salt 7‐chloro‐4‐[2‐(diethylammonio)ethylamino]quinolinium bis(dihydrogenphosphate) phosphoric acid, C15H22ClN32+·2H2PO4−·H3PO4, (III), was prepared in order to establish the protonation sites of these compounds. The phosphate ions form a two‐dimensional hydrogen‐bonded sheet, while the aminoquinoline cations are linked to the phosphates by N—H⋯O hydrogen bonds from each of their three N atoms. While the conformation of the quinoline region hardly varies between (I), (II) and (III), the amino side chain is much more flexible and adopts a significantly different conformation in each case. Aromatic π–π stacking interactions are the only supramolecular interactions seen in all three structures. 相似文献
139.
James L. Kelley James B. Thompson Virgil L. Styles Francis E. Soroko Barrett R. Cooper 《Journal of heterocyclic chemistry》1995,32(5):1423-1428
The 3H-imidazo[4,5-c]pyridazine, 1H-imidazo[4,5-d]pyridazine, and 1H-benzimidazole analogues of the potent anticonvulsant purine 9-(2-fluorobenzyl)-6-methylamino-9H-purine (1, 78U79) were synthesized and tested for anticonvulsant activity. The 3H-imidazo[4,5-c]pyridazines 8 and 9 were prepared in five stages from 3,4,5-trichloropyridazine (2) . The 1H-imidazolo[4,5-d]pyridazine 15 was synthesized in four stages from 5-[(benzyloxy)methyl]-1,5-dihydro-4H-imidazo[4,5-d] pyridazin-4-one (10a) . The benz-imidazole analogues 18 and 20 were prepared from 2,6-dinitroaniline in three stages. These compounds were one-tenth or less as active as 1 in protecting rats against maximal electroshock-induced seizures. 相似文献
140.
Stéphanie M. Cornet Andrés E. Goeta Judith A.K. Howard Mark D. Roden Amber L. Thompson 《Journal of organometallic chemistry》2005,690(16):3630-3637
Oxidative addition reactions of Cl2CPR (R = 2,4,6-tris(trifluoromethyl)phenyl (Ar) or 2,6-bis(trifluoromethyl)phenyl (Ar′) with Pt(PPh3)4 yield the cis and trans (at platinum) complexes [PtCl(ClCPAr)(PPh3)2] and [PtCl(ClCPAr′)(PPh3)2]. All starting materials and intermediates have been characterised by NMR spectroscopy. The crystal and molecular structures of the trans-platinum complexes have been determined by single-crystal X-ray diffraction at low temperature. 相似文献