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31.
Isosteric and integral heats of adsorption of xenon on Grafoil have been determined calorimetrically at 195.5 K and at surface coverages of up to 1.1.  相似文献   
32.
Luminescent ruthenium(II) complex covalently bound silica nanoparticles have been prepared and used as a probe for time-gated luminescence bioimaging. The new nanoparticles were prepared by copolymerization of a luminescent Ru(II) complex tris(5-amino-1,10-phenanthroline)ruthenium(II) conjugated with 3-aminopropyl(triethoxy)silane (APS-Ru conjugate), free (3-aminopropyl)triethoxysilane (APS) and tetraethyl orthosilicate (TEOS) in a water-in-oil reverse microemulsion consisting of Triton X-100, n-octanol, cyclohexane and water in the presence of aqueous ammonia. Characterization by transmission electron microscopy indicates that the nanoparticles are monodisperse, spherical and uniform in size, 64 ± 4 nm in diameter. Compared with the dye-doping nanoparticles, dye leakage of the new nanoparticles was remarkably decreased. In addition, it was found that the Ru(II) complex luminescence could be effectively enhanced with a longer luminescence lifetime (∼2.3 μs) after forming the nanoparticles, which enables the nanoparticles to be suitable as a bioprobe for time-gated luminescence bioimaging applications. The nanoparticle-labeled streptavidin was prepared and successfully used for time-gated luminescence imaging detection of an environmental pathogen, Giardia lamblia, with high specificity and sensitivity.  相似文献   
33.
J. Piper 《Optik》2009,120(18):963-975
Luminance contrast is a new illumination technique in light microscopy recently developed by the author, which leads to extraordinary contrast effects, enhanced focal depth and supramicroscopic resolution when transparent stained or unstained specimens are examined.This method is characterized by a small illuminating light beam running centrically to the specimen, so that the specimen is illuminated very homogenously. Within the objective, the illuminating beam is blocked by a small light stop. When all parts of the illuminating light are totally blocked, the background is completely dark; when small parts of the illuminating light pass the light stop, the background is moderately brightened.The microscopic image is a result of scattered light components, which are bent or reflected by the specimen. When the illuminating light is not completely blocked by the light stop, the transmitted illuminating components interfere with the scattered light components coming from the specimen.Additional three-dimensional effects are achievable when the illuminating light passes the specimen obliquely.The resulting variants of illumination are similar to dark field, negative phase contrast and interference contrast. In all modes of luminance contrast the specimen is illuminated very homogenously so that it appears as a self-luminous, fluorescent body – similar to fluorescence microscopy.Luminance contrast can be carried out when mirror objectives are used or common objectives containing glass lenses are equipped with individually adjusted light stops.Further aspects of technical developments are discussed in full details.  相似文献   
34.
Monitoring the optical field energies in an intracavity cascaded crystalline pulsed Raman laser enables us to probe the dynamics and optimise the performance of the laser, which produces up to 2.1 W average output power at 4 wavelengths between 532 and 636 nm selectable by simple angle tuning.  相似文献   
35.
36.
The transfer of electronic energy between metastable argon and ground-state oxygen atoms has been studied in a discharge-flow apparatus. The excitation energy of the argon metastables is transferred to the 3p 3P state of atomic oxygen with a cross section of 3 A2. The energy transfer is discussed in terms of an ionic-intermediate, curve-crossing mechanism for which the calculated cross section is 13 A2.  相似文献   
37.
The synthesis of a small library of differentially-linked beta-C-disaccharides has been carried out through the use of a radical allylation-RCM strategy. Acids 6 were prepared by Keck allylation of a suitable carbohydrate-based radical precursor, followed by oxidative cleavage of the formed alkene. Dehydrative coupling of these acids with the known olefin alcohol 5 then gave the precursor esters 7 in excellent yield. Methylenation of the esters 7 was followed by RCM and in situ hydroboration-oxidation of the formed glycals to furnish the protected beta-C-disaccharides 10 in good overall yield. Five examples were then deprotected and screened for their efficacy as enzyme inhibitors of beta-glycosidase and against several solid-tumor cell lines for in vitro differential cytotoxicity.  相似文献   
38.
Withford MJ  Brown DJ  Piper JA 《Optics letters》1998,23(19):1538-1540
The output power of a kinetically enhanced Cu-vapor laser is shown to increase linearly with pulse repetition frequency to an experimental limit of 22 kHz. Output power of >150 W has been produced by a medium-scale (38-mm diameter, 1.55-m long) device operating at 22 kHz.  相似文献   
39.
The variations in the output power of a copper vapour laser resulting from H2 additive to neon buffer gas are investigated for a wide range of pulse repetition frequencies (3.2 to 19.7 kHz). Small improvements in laser output power (9%) were observed for 2% H2-Ne admixture at low repetition frequency, these improvements becoming progressively larger (up to 250%) as the repetition rate increased. These observations are consistent with added H2 modifying the interpulse kinetics, thereby altering the spatiotemporal evolution of the output pulse. In particular, the observed average output power increases at elevated repetition rates owing to both increased laser pulse energy and increased optimum pulse repetition frequency.  相似文献   
40.
Zusammenfassung Reine Lipoproteinfraktionen des menschlichen Serums werden durch Gelfiltration auf Sepharose 2 B charakterisiert. Die SäulenkonstantenKd für die Chylomicronen, VLDL, LDL und HDL werden zu den Dichteklassen dieser Lipoproteine in Beziehung gesetzt. Die Befunde an den Reinfraktionen werden mit den Elutionsmustern des menschlichen Normalserums und des Serums bei Patienten mit einer Hyperlipoproteinämie vom Typ III mit einem abnormen-Lipoprotein verglichen. Die diagnostische Bedeutung der Sepharose 2 B-Gelfiltration für die Erkennung der Hyperlipoproteinämien wird diskutiert.
Characterisation of human serum lipoproteins by gel filtration on Agarose (Sepharose 2 B)
The constantKd for each fraction (chylomicrons, VLDL, LDL, HDL) is correlated to its density. The results with these pure fractions are compared with eluation patterns of normal serum and serum with hyperlipoproteinemia type III containing an abnormal-lipoprotein. The importance of agarose gel filtration for the diagnosis of hyperlipoproteinemias is discussed.


2%ige Agarosepräparation der Fa. Pharmacia Fine Chemicals, Uppsala, Schweden.  相似文献   
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