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261.
光纤布喇格光栅的制作和应用 总被引:1,自引:0,他引:1
本文简要介绍光纤布喇格光栅(FBG)的原理及性能,并给出FBG的制作方法。 相似文献
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Laboratorial diagnosis of paracoccidioidomycosis and new insights for the future of fungal diagnosis
Paracoccidioidomycosis (PCM) is the most prevalent mycosis in Latin-America. As for other mycosis, its importance of has been largely underestimated, partially due to the limited geographical distribution of the etiologic fungal agent (Paracoccidioides brasiliensis). However, the advent of AIDS and other immune suppressing conditions is creating an emergent need for improved diagnostic tests envisaging simpler, cheaper, faster and more sensitive and accurate detection of pathogenic fungi, especially those causing systemic and opportunistic diseases. Routine laboratorial diagnosis of PCM disease relies mainly on direct observation of the fungus. However, culture growing is slow and, too often, definite diagnosis can only be obtained at later growing stages. Immunodiagnosis is also widely employed, although usually cumbersome and complex. Enzyme-based immunoassays are more amenable to automation for high-throughput testing, but may lead to cross-reactivity with other fungi. Plus, molecular diagnosis relying on polymerase-chain reaction (PCR) and nucleic-acid hybridization, although still at early stages of application to routine diagnosis of P. brasiliensis, has triggered the development of techniques for its improved specific detection, thus contributing for epidemiological studies as well. In the future, microarrays and newer biosensing technologies, coupled to new bionanotechnological tools, will certainly improve diagnosis of PCM and other mycosis through very specific and sensitive pathogen biomolecular detection. 相似文献
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Fourier transform infrared microscopic imaging (FTIRI) was used to quantitatively examine the anisotropies of proteoglycan (PG) and collagen in articular cartilage. Dried 6 μm thick sections of canine humeral cartilage were imaged at 6.25 μm pixel-size in FTIRI with an infrared analyzer set at 26 different angles between 0° and 180° polarization. Like the amide II and amide III peaks, the 1338 cm−1 band confirms the anisotropy of collagen fibrils in cartilage. The absorption profile of the sugar band shows an anisotropic flipping at the deeper part in the radial zone, just above the tidemark. Together with the reduction in the PG concentration and subsequent increase in tissue calcification in this region, this anisotropy flipping of sugar might be caused by the orientational change in the collagen-attaching PG from orthogonal to parallel when the fibrils are entering the calcified zone. 相似文献
265.
Yaqi Chen Christine H. Moran Zhao Tan A. Lake Wooten Joseph A. O'Sullivan 《Journal of Raman spectroscopy : JRS》2013,44(5):703-709
To drive the application of surface‐enhanced Raman spectroscopy (SERS) mapping in ex vivo diagnostic imaging and non‐biological material characterization, we have designed a robust and accurate multiplex spectral fitting method using an alternating minimization algorithm to extract individual constituent Raman spectra with very small overall fitting error (as low as 2%). For each mixed Raman signal, constituent spectra and mixture coefficients were estimated jointly based on reference spectra that were measured in the lab. Our method is based on a Poisson model to reflect the photon counting nature of Raman signals and includes the nonlinear noise in the measured data, making our method robust against data containing relatively large random noise. In our method, we minimized a cost function consisting of two terms: (1) the overall fitting error between the measured and modeled spectra and (2) the sum of the individual error between each reference spectrum and its corresponding constituent. This method inherently guarantees that the estimates will approach the global minimum with monotonic convergence. The accuracy of our method was validated by applying it to a SERS spectral fitting problem and comparing our results to those from existing methods. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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This study was conducted to develop systems for the identification of four tuna species (skipjack tuna Katsuwonus pelamis, yellowfin tuna Thunnus albacares, bullet tuna Auxis sp. and Atlantic bonito Sarda sp). At first, raw samples of these species and a mix intended as internal control were prepared for the authentication of fish muscle tissue of the genus Thunnus sp., Auxis sp. and Sarda sp. DNA from raw muscle tissue, the mix and samples was extracted with the DNeasy mericon Food Kit (Qiagen GmbH, Hilden, Germany). The concentration and purity of DNA in raw samples were evaluated using a spectrophotometer. Primers and probe sequences were specifically designed to identify the selected species. In addition, primers and a probe for the endogenous 12S rRNA gene were designed to determine the presence of amplifiable fish (especially tuna) DNA in samples. Furthermore, the species specificity of the designed primers and probes was verified in DNA samples of various tuna and bonito species. Limit of detection for the selected species was calculated as well as the coefficient of determination R2 and efficiency of real-time PCR testing was determined. To evaluate the developed real-time PCR methods, 70 commercial tuna products were analysed. The results show that mislabelling of fish products can still be encountered and, moreover, the presence of an additional species can be identified. 相似文献
268.
Miroslav Kuba Dr. Tomáš Kraus Dr. Radek Pohl Prof. Dr. Michal Hocek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(52):11950-11954
Thymidine triphosphate bearing benzylidene-tetrahydroxanthylium near-IR fluorophore linked to the 5-methyl group via triazole was synthesized through the CuAAC reaction and was used for polymerase synthesis of labelled DNA probes. The fluorophore lights up upon incorporation to DNA (up to 348-times) presumably due to interactions in major groove and the fluorescence further increases in the single-stranded oligonucleotide. The labelled dsDNA senses binding of small molecules and proteins by a strong decrease of fluorescence. The nucleotide was used as a light-up building block in real-time PCR for detection of SARS-CoV-2 virus. 相似文献
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Ruobing Shi Yucong WangYunli Hu Lei ChenQian-Hong Wan 《Journal of chromatography. A》2009,1216(36):6382-6386
Solid-phase extraction has been widely employed for the preparation of DNA templates for polymerase chain reaction (PCR)-based analytical methods. Among the variety of adsorbents studied, magnetically responsive silica particles are particularly attractive due to their potential to simplify, expedite, and automate the extraction process. Here we report a facile method for the preparation of such magnetic particles, which entails impregnation of porous silica microspheres with iron salts, followed by calcination and reduction treatments. The samples were characterized using powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms, and vibrating sample magnetometry (VSM). XRD data show that magnetite nanocrystals of about 27.2 nm are produced within the pore channels of the silica support after reduction. SEM images show that the as-synthesized particles exhibit spherical shape and uniform particle size of about 3 μm as determined by the silica support. Nitrogen sorption data confirm that the magnetite-loaded silica particles possess typical mesopore structure with BET surface area of about 183 m2/g. VSM data show that the particles display paramagnetic behavior with saturation magnetization of 11.37 emu/g. The magnetic silica microspheres coated with silica shells were tested as adsorbents for rapid extraction of genomic DNA from soybean-derived products. The purified DNA templates were amplified by PCR for screening of genetically modified organisms (GMOs). The preliminary results confirm that the DNA extraction protocols using magnetite-loaded silica microspheres are capable of producing DNA templates which are inhibitor-free and ready for downstream analysis. 相似文献