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81.
Activity-based protein profiling (ABPP) is a powerful technique to label and detect active enzyme species within cell lysates, cells, or whole animals. In the last two decades, a wide variety of applications and experimental read-out techniques have been pursued in order to increase our understanding of physiological and pathological processes, to identify novel drug targets, to evaluate selectivity of drugs, and to image probe targets in cells. Bioorthogonal chemistry has substantially contributed to the field of ABPP, as it allows the introduction of tags, which may be bulky or have unfavorable physicochemical properties, at a late stage in the experiment. In this review, we give an overview of the bioorthogonal reactions that have been implemented in ABPP, provide examples of applications of bioorthogonal chemistry in ABPP, and share some thoughts on future directions.  相似文献   
82.
Microbial treatments of waste water can be done in membrane reactors. A membrane installed outside the reactor is used to separate bacteria from the treated effluent.

A new membrane reactor concept is presented. The separation membrane is introduced in the reactor and not outside as in a normal one. The membrane plays the role of a separator of two streams and is used at the same time as the immobilizing support for the bacteria.

The reactor keeps the bacteria active via a specific nutrient stream that is provided on one side of the membrane. The bacteria grow in and on the membrane where they form an active biofilm. The bacteria can treat the effluent on one side and can be kept active via the nutrient stream at the other side without contamination of the effluent by the nutrient.

In this work, the performance of the BICMER (Bacteria Immobilized Composite MEmbrane Reactor) is demonstrated via treatments of effluents containing heavy metals or organic xenobiotics.

For heavy metal removal Alcaligenes eutrophus CH34 bacteria were used. These bacteria induce a metal bioprecipitation process that results in the formation of crystalline metal carbonates, which are recovered on a separate column in the reactor. In this way metals can be recovered without disturbing the biofilm on the membrane. Metals such as Cd, Zn, Cu, Pb and Y can be reduced to less than 50 ppb. The metals Co, Ni, Pd and Ge are reduced to below 100 ppb.

For organic xenobiotics Alcaligenes eutrophus AE1308 bacteria or other strains (depending on the xenobiotic to be degraded) were used. This strain degrades the xenobiotic 3-chlorobenzoate (Cba) and 2,4-dichlorophenoxyacetic acid to CO2, H2O and chloride). Concentrations of 3 mM Cba could be reduced to less than 0.1 mM. For other toxic organic compounds, different biodegrading strains need to be used.  相似文献   

83.
Trapping of vortices in a cavity has been explored in recent years as a drag reduction measure for thick airfoils. If, however, trapping fails, then oscillation of the cavity flow may couple with elastic vibration modes of the airfoil. To examine this scenario, the effect of small amplitude vertical motion on the oscillation of the shear layer above the cavity is studied by acoustic forcing simulating a vertical translation of a modified NACA0018 profile. At low Reynolds numbers based on the chord (O(104)), natural instability modes of this shear layer are observed for Strouhal numbers based on the cavity width of order unity. Acoustic forcing sufficiently close to the natural instability frequency induces a strong non-linear response due to lock-in of the shear layer. At higher Reynolds numbers (above 105) for Strouhal number 0.6 or lower, no natural instabilities of the shear layer and only a linear response to forcing were observed. The dynamical pressure difference across the airfoil is then dominated by added mass effects, as was confirmed by numerical simulations.  相似文献   
84.
A comparison has been made of the morphology of fibrillar polyethylene crystals prepared by shear-induced crystallization and heterogeneous Ziegler-Natta catalysis under similar solvent and temperature conditions. Both specimens had a shish-kebab superstructure consisting of lamellar overgrowths on a filamentary backbone. For polyethylenes stirrer-crystallized at small supercoolings, the overgrown lamallae were removed by nitric acid oxidation followed by selective dissolution, leaving naked filamentary ribbons. Thermal analysis of these specimens suggested a dual molecular conformation of both folded and extended chains. The fact that these fibrils did not deform easily under uniaxial stress conforms with a core of extended chains. Thermal and oxidative behavior of polyethylenes prepared at lower crystallization temperatures suggested a greater content of chain folds in the central thread as the degree of supercooling increased. The Ziegler-Natta fibrils were degraded into lamellar fragments on oxidation and their thermal behavior suggested a predominantly folded-chain conformation. Uniaxial deformation occurred on stretching the Ziegler-Natta specimens in harmony with a core of folded chains. Molecular models have been proposed to account for the observed phenomena.  相似文献   
85.
The invariance of the topological degree under certain homotopies is used to derive a framework for tests to computationally prove the existence of zeros of nonlinear mappings in . These tests use interval arithmetic to enclose the range of a function over a box and are provably more general than many other tests like the Moore–Kioustelidis test, a test based on the Krawczyk operator, and another degree–based test published recently. A numerical example is included.  相似文献   
86.
We investigate and characterize ideals in a group algebra KG which have complementary duals, i.e., ideals C in KG which satisfy \(KG = C \oplus C^\perp .\) In the special case that G is a cyclic group we get an early result of Yang and Massey as an easy consequence.  相似文献   
87.
Freestanding multilayer films prepared by layer‐by‐layer technique have attracted interest as promising materials for wound dressings. The goal is to fabricate freestanding films using chitosan (CHI) and alginate (ALG) including subsequent crosslinking to improve the mechanical properties of films while maintaining their biocompatibility. Three crosslinking strategies are investigated, namely use of calcium ions for crosslinking ALG, 1‐ethyl‐3‐(‐3‐dimethylaminopropyl) carbodiimide combined with N‐hydroxysuccinimide for crosslinking ALG with CHI, and Genipin for crosslinking chitosan inside the films. Different characteristics, such as surface morphology, wettability, swelling, roughness, and mechanical properties are investigated showing that films became thinner, exhibited rougher surfaces, had lower water uptake, and increased mechanical strength after crosslinking. Changes of wettability are moderate and dependent on the crosslinking method. In vitro cytotoxicity and cell attachment studies with human dermal fibroblasts show that freestanding CHI‐ALG films represent a poorly adhesive substratum for fibroblasts, while studies using incubation of plastic‐adherent fibroblast beneath floating films show no signs of cytotoxicity in a time frame of 7 days. Results from cell experiments combined with film characteristics after crosslinking, indicate that crosslinked freestanding films made of ALG and CHI may be interesting candidates for wound dressings.  相似文献   
88.
89.
In this paper we develop various representations for systems described by aset of high-order differential equations of the form R0w + R1w + … + Rsw(s) = 0, withR0, R1,…, Rs not necessarily square matrices. The variables w are the external variables. Particular attention is paid to the problem of obtaining minimal state-space realizations and input-output or input-state-output representations of such systems.  相似文献   
90.
Flue instruments such as the recorder flute and the transverse flute have different mouth geometries and acoustical response. The effect of the mouth geometry is studied by considering the aeroacoustical response of a simple whistle. The labium of a transverse flute has a large edge angle (60 degrees) compared to that of a recorder flute (15 degrees). Furthermore, the ratio W/h of the mouth width W to the jet thickness h can be varied in the transverse flute (lips of the musician) while it is fixed to a value W/h approximately 4 in a recorder flute. A systematic experimental study of the steady oscillation behavior has been carried out. Results of acoustical pressure measurements and flow visualization are presented. The sharp edge of the recorder provides a sound source which is rich in harmonics at the cost of stability. The larger angle of the labium of the flute seems to be motivated by a better stability of the oscillations for thick jets but could also be motivated by a reduction of broadband turbulence noise. We propose two simplified sound source models which could be used for sound synthesis: a jet-drive model for W/h>2 and a discrete-vortex model for W/h<2.  相似文献   
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