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271.
Deoxynivalenol and T-2 toxin were extracted from wheat-based bread (n = 75) and pasta (n = 75) samples using a mixture of acetonitrile:water (86:14 v/v); for analysis, gas chromatography/mass spectrometry after derivatisation with trifluoroacetic anhydride was utilised. The recovery of deoxynivalenol and T-2 toxin from both food matrixes ranged from 90.1 to 94.0%. The occurrence of these mycotoxins in bread was 28.0% and 2.6% for deoxynivalenol and T-2 toxin, respectively, whereas in pasta, the occurrence of both mycotoxins was higher, varying from 9.3 to 62.7%. The mean content of deoxynivalenol (42.5 μg/kg) in bread was lower than the content of T-2 toxin (68.37 μg/kg), while in pasta the content of deoxynivalenol (137.1 μg/kg) was superior. The estimated daily intake of deoxynivalenol and T-2 toxin from the consumption of these products represents 8.4% and 0.2% of the tolerable daily intake, respectively. These results back up the necessity to take a vigilant attitude in order to prevent human intake of trichothecenes. This information is necessary and of high priority in order to protect the consumer’s health from the risk of exposure to these toxins. 相似文献
272.
N. Mahnine G. Meca A. Elabidi M. Fekhaoui A. Saoiabi G. Font J. Mañes A. Zinedine 《Food chemistry》2011
Sixty-eight samples of cereals products, including breakfast cereals (n = 48) and infant cereals (n = 20), purchased from supermarkets and pharmacies in Rabat-Salé area from Morocco were analysed for the determination of six emerging mycotoxins: four enniatins ENs (ENA, ENA1, ENB and ENB1), beauvericin (BEA) and fusaproliferin (FUS). Samples were extracted with a mixture of acetonitrile:water (85:15, v/v), using an Ultra-Turrax® homogeniser. Mycotoxins were then identified and quantified by liquid chromatography (LC) with diode array detection (DAD). Positive samples were confirmed by LC–MS/MS. 相似文献
273.
Moon-Sung Cho Ki-Seob Sim Ho Chun Suk Seok-Kyu Chang 《Nuclear Engineering and Design》2000,200(3):407-419
A static analysis, finite-element (FE) model was developed to simulate out-reactor fuel–string strength tests with use of the well-known, structural analysis computer code ABAQUS. The FE model takes into account the deflection of fuel elements, and stress and displacement in endplates subjected to hydraulic drag loads. It was adapted to the strength tests performed for CANFLEX 43-element bundles and the existing 37-element bundles. The FE model was found to be in good agreement with experiment results. With use of the FE model, the static behavior of the fuel bundle string, such as load transfer between ring elements, endplate rib effects, hydraulic drag load incurring plastic deformation in fuel string and hydraulic flow rate effects were investigated. 相似文献
274.
Márcia Beatriz Reis Fróes Luis Fabrício Santana Santos Sandro Navickiene 《Food Analytical Methods》2013,6(1):328-333
An extraction method based on matrix solid phase dispersion was developed to determine bromuconazole, fenbuconazole, parathion-methyl, kresoxim-methyl, and teflubenzuron in açai using liquid chromatography with ultraviolet diode array detector. The best results were obtained using 1.0 g of açai, 3.0 g of neutral alumina as the dispersant sorbent, and cyclohexane/ethyl acetate (1:1, v/v, 20 mL) as an eluting solvent. The method was validated using açai samples fortified with pesticides at three concentration levels (0.25, 0.5, and 1.0 mg kg?1). Average recoveries (seven replicates) ranged from 66 to 119 %, with relative standard deviations between 1.4 and 20 %. The detection and quantification limits for açai ranged from 0.02 to 0.05 mg kg?1 and from 0.05 to 0.1 mg kg?1, respectively. 相似文献
275.
In computed tomography, targeted (or zoomed) reconstruction is usually used to achieve high-resolution reconstruction to a small region-of-interest (ROI). This paper reports a novel targeted reconstruction method based on the recently developed differential planar computed tomography technology. With the central-slice sinogram of scanning a planar object, the primary orientation of the object is first determined for the first projection. Then by identifying the dimensions of the ROI and its offsets to the centre-of-rotation (COR), the targeted reconstruction matrix is defined, which just covers the ROI and follows its initial orientation at the scan start time. By scanning and reconstructing a small planar ROI soldered on a large planar substrate, we demonstrate the advantages of the proposed method over traditional CT, including the smaller reconstruction size and less computation time, high-resolution reconstruction and good-orientated CT image for subsequent de-layering and visualization. 相似文献
276.
Nuno A. Costa Daniela Martins João Pereira Jorge Martins João Ferra Paulo Cruz Adélio Mendes Fernão D. Magalhães Luísa H. Carvalho 《应用聚合物科学杂志》2013,130(6):4500-4507
The chemical structure of amino adhesives produced by the strongly acid process was investigated by 13C Nuclear Magnetic Resonance spectroscopy. This technique allowed the identification of functional groups and its quantitative determination. Concentration of cyclic polymeric structures (urons) was shown to be related with adhesive performance and with particleboard physico‐mechanical properties and formaldehyde content. Higher urons concentration presented lower viscosity and reactivity. Particleboards produced with resins with lower urons concentration presented lower formaldehyde content, but also lower internal bond strength. Wood‐based panels produced fulfilled E1 class requirements for formaldehyde emissions, indicating that strongly acid process is an alternative to the conventional alkaline–acid process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4500–4507, 2013 相似文献
277.
The corrosion distribution along a coil-coating sample formed by deep-drawing is reported. The formed rectangular cup was divided in five different regions and their impedance response investigated independently. The response of each region was compared with the overall sample response and the morphology of degradation was studied by scanning electron microscopy. Severe attack was observed in the most strained regions (corners and edges). Micro-defects in the shape of pinholes and cracks developed as a consequence of the forming process, apparently nucleating in the vicinity of the inorganic particles present in the paint. Immersion increased the size and number of defects. The overall impedance was reconstructed from the impedance measured in the local regions by two methods: (a) calculation using the local experimental data and (b) simulation using an equivalent electrical circuit with the values taken from the fitting of the local experimental data. 相似文献
278.
The trans fatty acid (TFA) patterns in the fats of ruminant meat and dairy products differ from those found in other (processed) fats.
We have evaluated different TFA isomers in human breast milk as an indicator of dietary intake of ruminant and dairy fats
of different origins. Breast milk samples were collected 1 month postpartum from 310 mothers participating in the KOALA Birth
Cohort Study (The Netherlands). The study participants had different lifestyles and consumed different amounts of dairy products.
Fatty acid methyl esters were determined by GC-FID and the data were evaluated by principal component analysis (PCA), ANOVA/Post
Hoc test and linear regression analysis. The two major principal components were (1) 18:1 trans-isomers and (2) markers of dairy fat including 15:0, 17:0, 11(trans)18:1 and 9(cis),11(trans)18:2 (CLA). Despite similar total TFA values, the 9(trans)18:1/11(trans)18:1-ratio and the 10(trans)18:1/11(trans)18:1-ratio were significantly lower in milk from mothers with high dairy fat intake (40–76 g/day: 0.91 ± 0.48, P < 0.05) compared to low dairy fat intake (0–10 g/day: 1.59 ± 0.48), and lower with strict organic meat and dairy use (>90%
organic: 0.92 ± 0.46, P < 0.05) compared to conventional origin of meat and dairy (1.40 ± 0.61). Similar results were obtained for the 10(trans)18:1/11(trans)18:1-ratio. We conclude that both ratios are indicators of different intake of TFA from ruminant and dairy origin relative
to other (including industrial) sources. 相似文献
279.
The two-dimensional suffix tree of a matrix A is a compacted tree that represents all square submatrices of A. We present the first complete version of a deterministic linear-time algorithm to construct the two-dimensional suffix tree
by applying a divide-and-conquer approach. 相似文献
280.
Arylamine N-acetyltransferases (NATs) are found in many eukaryotic organisms, including humans, and have previously been identified in the prokaryote Salmonella typhimurium. NATs from many sources acetylate the antitubercular drug isoniazid and so inactivate it. nat genes were cloned from Mycobacterium smegmatis and Mycobacterium tuberculosis, and expressed in Escherichia coli and M. smegmatis. The induced M. smegmatis NAT catalyzes the acetylation of isoniazid. A monospecific antiserum raised against pure NAT from S. typhimurium recognizes NAT from M. smegmatis and cross-reacts with recombinant NAT from M. tuberculosis. Overexpression of mycobacterial nat genes in E. coli results in predominantly insoluble recombinant protein; however, with M. smegmatis as the host using the vector pACE-1, NAT proteins from M. tuberculosis and M. smegmatis are soluble. M. smegmatis transformants induced to express the M. tuberculosis nat gene in culture demonstrated a threefold higher resistance to isoniazid. We propose that NAT in mycobacteria could have a role in acetylating, and hence inactivating, isoniazid. 相似文献