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51.
Measurement of in vivo sunscreen immune protection factors in humans   总被引:2,自引:0,他引:2  
This study investigates the level of protection provided by sunscreens against solar-simulated UV radiation-induced immunosuppression in humans. The in vivo immune protection factors (IPF) of two broad-spectrum sunscreens were determined by assessing their ability to prevent UV-induced suppression of nickel contact hypersensitivity (CHS) in 15 nickel-allergic volunteers. Each volunteer was irradiated on unprotected skin of the back with different doses of UV daily for 4 days. Multiples of these UV doses were concurrently delivered to sunscreen-treated sites on the contralateral back. Nickel patches were then applied to both irradiated sites and adjacent, unirradiated control sites. Nickel-induced erythema at each site was measured 72 h later with a reflectance spectrometer. Comparison of the nickel reactions of irradiated and unirradiated skin revealed linear UV dose-responses for immunosuppression in both unprotected and sunscreen-treated skin. The minimum level of immunosuppression that can be reliably detected with this method is 20%. Therefore, the UV dose that reduces mean nickel CHS by 20% is the minimal immune suppression dose (MISD). Sunscreen IPF were determined by dividing the mean MISD of sunscreen-treated skin by that of unprotected skin. The sunscreens, with sun protection factors of 9 and 24, had IPF of 6.5 and > 25, respectively.  相似文献   
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This article presents two case studies, concerning the allocation of £Billions by a mechanism communicated via spreadsheet models. It argues that technical analytic skills as well as policy development skills are a vital component of governance. In the UK, Central Government uses funding formulae to distribute money to local service providers. One commonly stated goal of such formulae is equity of service provision. However, given the complexity of public services, together with variations in need, delivery style and the exercise of stakeholder judgement as to which needs should be met and how, such formulae frequently obscure the process by which equity has been taken into account. One policy ‘solution’ to managing such tensions is to seek ‘transparency’. With respect to funding formulae, this commonly involves publishing the underlying data and formulae in spreadsheets. This paper extends the argument that such ‘transparency’ requires an audience that understands the policy assumptions (and related conceptualisations), data sources, methodological approaches and interpretation of results. It demonstrates how the search for policy ‘transparency’ is also met by the technical quality assurance goals that the operational research community would recognise as best practice in the development both of software generally and spreadsheet models specifically. Illustrative examples of complex formulae acting to subvert equity are drawn from the English Fire and Rescue Service and Police Service allocation formulae. In the former, an increase in the amount of deprivation, as measured by one of six indicators, has the perverse effect of decreasing the financial allocation. In the latter, metropolitan areas such as London are found to gain most from the inclusion of variables measuring sparsity. The conclusion from these scenarios is that the steps needed to for technical quality assurance and policy transparency are mutually reinforcing goals, with policy analysts urged to make greater use of technical analytic skills in software development.  相似文献   
54.
A novel and robust automated docking method that predicts the bound conformations of flexible ligands to macromolecular targets has been developed and tested, in combination with a new scoring function that estimates the free energy change upon binding. Interestingly, this method applies a Lamarckian model of genetics, in which environmental adaptations of an individual's phenotype are reverse transcribed into its genotype and become heritable traits (sic). We consider three search methods, Monte Carlo simulated annealing, a traditional genetic algorithm, and the Lamarckian genetic algorithm, and compare their performance in dockings of seven protein–ligand test systems having known three-dimensional structure. We show that both the traditional and Lamarckian genetic algorithms can handle ligands with more degrees of freedom than the simulated annealing method used in earlier versions of AUTO DOCK , and that the Lamarckian genetic algorithm is the most efficient, reliable, and successful of the three. The empirical free energy function was calibrated using a set of 30 structurally known protein–ligand complexes with experimentally determined binding constants. Linear regression analysis of the observed binding constants in terms of a wide variety of structure-derived molecular properties was performed. The final model had a residual standard error of 9.11 kJ mol−1 (2.177 kcal mol−1) and was chosen as the new energy function. The new search methods and empirical free energy function are available in AUTO DOCK , version 3.0. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 1639–1662, 1998  相似文献   
55.
Framing effects of television news coverage of social protest   总被引:1,自引:0,他引:1  
We investigated framing effects of television news coverage of an anarchist protest. Three treatment stories differed in their level of status quo support. Status quo support had significant effects on viewers, leading them to be more critical of, and less likely to identify with, the protesters; less critical of the police; and less likely to support the protesters' expressive rights. Status quo support also produced lower estimates of the protest's effectiveness, public support, and perceptions of newsworthiness. The results substantiate concerns about status quo support by showing that it can influence audience perceptions.  相似文献   
56.
The theory of media events developed by Dayan and Katz is extended in an analysis of Franklin Roosevelt's first eight fireside chats. Roosevelt's fireside chats were structured in both form and content by the new mode of publicness initiated by the culture industries in the 20th century. Roosevelt employed the idioms of mass culture to close the perceptual gap between him and his mass audience. As media events, the chats were useful in dramatizing a new symbolic geography of the American imagined community for the mass public, and thus in introducing to this public a set of new identities and practices appropriate to 20th-century mass politics.  相似文献   
57.
The mixed compact-non-compact U(1) model is shown to be equivalent to a compact U(1) Higgs model. It is argued that the mixed SO(3)-SU(2) model is dual to an SO(3) gauge theory coupled to a scalar field in the fundamental representation. The degrees of freedom are Z(2) monopoles and charges or, in a dual picture, monopoles and loops. This picture is supported by a Monte Carlo calculation. The implications for the SU(2) transition region are discussed.  相似文献   
58.
59.
[reaction: see text] A practical, one-pot, two-step catalytic method is described for the synthesis of 2,5-diformylfuran (DFF) from fructose via dehydration to 5-(hydroxymethyl)furfural (HMF), followed by in situ catalytic air-oxidation.  相似文献   
60.
Rehkämper M  Halliday AN 《Talanta》1997,44(4):663-672
Two new aniondashexchange techniques have been developed for the separation of the platinum group elements Ru, Pd, Ir, Pt and the siderophile metals Re, Ag, Zn and Cd from geological samples following a NiS fire assay digestion procedure. Both methods are simple and permit the isolation of these elements in sufficient purity for quantitative analysis by isotope dilutiondashinductively coupled plasma mass spectrometry (ID-ICPMS) at yields of 75-95%. The high affinity of the considered elements to anion exchange resins allows the use of small (1.25 ml) columns even for the processing of 5-10 g sized silicate rock samples. Following fire assay digestion and dissolution of the NiS buttons in aqua regia, the samples are loaded onto the resin bed as solutions in 1 M HCl. After elution of the bulk sample matrix with dilute HCl and HNO(3), Zn and Cd are stripped from the column using 0.8 M HNO(3). Small amounts of bromine water are added to the dilute mineral acids for the stabilization of strongly retained Ir(IV). Following this, the iondashexchange techniques permit the sequential elution of Ag, Re and the PGE using 11 M HCl, 8 M HNO(3) and 13.5 M HNO(3). The iondashexchange methods have been applied to separation of Ru, Pd, Re, Ir and Pt from the geological reference material SU-la prior to concentration measurements by ID-ICPMS. Our analytical results are in good agreement with previously published data for this sample and display an external reproducibility (based upon repeat dissolutions) of approximately 2-10% for the elements considered in this study.  相似文献   
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