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51.
A homogeneous and disordered assembly of densely packed nanocrystals is generated without the assistance of organic molecules, from an aqueous solution at room temperature. The densely packed nanocrystals of tin dioxide (SnO2) and titanium dioxide (TiO2), 2–3 nm in size, form glassy macroscopic transparent objects of 2–10 mm. The monodisperse nanocrystals, which have a surface hydrated layer and are synthesized in aqueous solution, are densely packed in an homogeneous and disordered assembly through the evaporation of water as the dispersion medium. The formation of transparent bulk objects on the macroscopic scale originates from the homogeneous and disordered nature of the densely packed nanocrystals. The resultant homogeneous architectures are distinguishable from the typical inhomogeneous and disordered aggregates of nanoparticles observed after evaporation of the dispersion medium. Among superstructures based on nanocrystals, such as superlattices and mesocrystals, the resultant homogeneous and disordered assembly can be regarded as a new class of solid‐state material. 相似文献
52.
Janicka M Kot-Wasik A Kot J Namieśnik J 《International journal of molecular sciences》2010,11(11):4631-4659
Isoprostanes (IsoPs) are key biomarkers for investigating the role of free radical generation in the pathogenesis of human disorders. To solve IsoPs-related problems with regard to isoprostanes, analytical tools are required. This paper reviews the problems and trends in this field focusing on the methodology for assaying biomarkers in exhaled breath condensate (EBC) samples. A large amount of work has been done in the qualitative and quantitative analysis of IsoPs, but a standardized method has yet to emerge. The methodologies described differ, either in the sample preparation steps or in the detection techniques, or both. Requiring a number of chromatographic steps, the relevant extraction and purification procedures are often critical and time-consuming, and they lead to a substantial loss of target compounds. Recent data show that EBC is a promising non-invasive tool for the evaluation of different diseases. Two main analytical approaches have been adopted for IsoPs measurement: immunological methods and mass spectrometry. The methodologies for the extraction, purification and analysis of IsoPs in EBC samples are presented. 相似文献
53.
54.
Yuya Tachibana Takuya Maeda Osamu Ito Yasukatsu Maeda Masao Kunioka 《International journal of molecular sciences》2009,10(8):3599-3615
We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet. 相似文献
55.
The methanol extract obtained from the ripe fruits of Cornus mas L. (Cornaceae) have been phytochemically studied. On the basis of HPLC–PDA–MS/MSn analysis eight compounds have been identified as quercetin, kaempferol, and aromadendrin glycosilated derivatives. Three major compounds have been also isolated by Sephadex LH-20 column chromatography followed by HPLC and characterised by NMR spectroscopy. Moreover, LC–PDA–MS analysis of the red pigment revealed the presence of three anthocyanins. The quantitative analysis of all compounds was reported. 相似文献
56.
Kiwa Kitada Siti Machmudah Mitsuru Sasaki Motonobu Goto Yuya Nakashima Shoichiro Kumamoto Takashi Hasegawa 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(5):657-661
BACKGROUND: Chlorella vulgaris is a green microalgae that contains various pigment components of carotenoids and chlorophylls. Supercritical CO2 is widely used for extraction of pharmaceutical compounds because it is non‐oxic and easily separated from extracted material by simply depressurizing. In this work, pharmaceutical compounds from Chlorella vulgaris have been extracted using supercritical CO2 with or without entrainer at various extraction conditions. RESULTS: Based on high performance liquid chromatography (HPLC) analysis, the extracts contained pigment components, such as lutein, β‐carotene, chlorophyll a and b. Higher extraction pressure and temperature promoted higher lutein extraction by supercritical CO2. The optimum pressure and temperature for extraction were obtained as 50 MPa and 80 °C. Ethanol as an entrainer was more effective than acetone for the extraction of pigment components. Pigment components in the extract obtained by supercritical CO2 with and without entrainer were compared with the extract obtained by a conventional extraction method. CONCLUSION: Supercritical CO2 has been successfully applied for the extraction of pigment components from Chlorella vulgaris. Supercritical CO2 enabled high selectivity for lutein extraction; however, the lutein yield was lower than that obtained by extraction using supercritical CO2 with ethanol and soxhlet. Copyright © 2008 Society of Chemical Industry 相似文献
57.
Norihito Mayama Hiroyuki Yoshida Tatsuo Iwata Kaoru Sasakawa Atsushi Suzuki Yuya Hanaoka Yoshihiro Morita Akito Kuroda Masanori Owari 《Diamond and Related Materials》2010,19(7-9):946-949
In this study, we report the characterization of carbonaceous films deposited on metal substrates by liquid-phase electrodeposition in methanol. The characterization of carbonaceous films by electrodeposition was examined by means of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), secondary ion mass spectrometry (SIMS), atom probe (AP) and high resolution-elastic recoil detection analysis (HR-ERDA). From these results, it was found that the films deposited on the metal substrates were composed of the sp2 and sp3 carbon contents, of which the ratio was about 7:3. Furthermore, the films by electrodeposition contained much hydrogen. The hydrogen contents in the surface were about 60 at.% and those in the subsurface were a few 10 at.%. 相似文献
58.
M. Niraula K. Yasuda Y. Nakanishi K. Uchida T. Mabuchi Y. Agata K. Suzuki 《Journal of Electronic Materials》2004,33(6):645-650
The growth characteristics of thick (100) CdTe epitaxial layers of a thickness up to 200 μm on a (100) GaAs substrate in a
metal-organic vapor-phase epitaxy (MOVPE) system and fabrication of CdTe/n+-GaAs heterojunction diodes for their possible applications in low-energy x-ray imaging detectors are reported. The grown
epilayers were of high structural quality as revealed from the x-ray double-crystal rocking curve (DCRC) analysis, where the
full-width at half-maximum (FWHM) values of the (400) diffraction peaks was between 50 arcsec and 70 arcsec. The 4.2-K photoluminescence
(PL) showed high-intensity bound-excitonic emission and very small defect-related peaks. The heterojunction diode fabricated
had a good rectification property with a low value of reverse-bias current. The x-ray detection capability of the diode was
examined by the time-of-flight (TOF) measurement, where good bias-dependent photoresponse was observed, but no carrier transport
property could be deduced. It was found that the CdTe layer has a large number of trapping states as attributed to the cadmium-related
vacancy and Ga-impurity, diffused from the substrate, related defect complexes. 相似文献
59.
Shan Jiang Thammanoon Sreethawong Serina Siew Chen Lee Michelle Bee Jin Low Khin Yin Win Agata Maria Brzozowska Serena Lay‐Ming Teo G. Julius Vancso Dominik Jaczewski Ming‐Yong Han 《Advanced Materials Interfaces》2015,2(3)
With the ban of tributyltin, copper‐based biocides are now widely used in antifouling coatings as the major active ingredients. Given the past experience of heavy‐metal accumulation in harbors with limited water exchange, there is a significant interest in developing copper materials that greatly reduce the amount of copper ions released into marine surroundings. In this paper, copper nanowires (NWs) encapsulated in polymer matrices are investigated as the means to control the release of copper ions and to achieve a long‐lasting antifouling effect. Very long CuNWs with high aspect ratio in organic solution are drop‐coated onto substrates to fabricate uniform thin films. They are then incorporated into an elastomeric polydimethylsiloxane (PDMS) matrix. A small amount of CuNWs in PDMS can inhibit barnacle cyprid settlement, while it exhibits low mortality to cyprids and nauplii present in the surrounding seawater environment. The low levels of copper released after 50 days suggest that the intersecting and interconnected CuNWs embedded in PDMS could potentially release copper ions continuously over a few years in seawater. This approach provides a novel platform to use hybrid materials as effective marine antifouling coatings, and may be applied to fouling release materials to enhance their antifouling properties. 相似文献
60.
随着农民收入的增加,农民对居住条件的改善要求更加强烈,而对于自身住房的造价则尤为关注。对于新农村居住小区的建设而言,施工阶段合理的控制造价有着重要的意义。 相似文献