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211.
Batch copper ion binding and exchange properties of peat 总被引:5,自引:0,他引:5
Cupric ion fixation by raw peat is likely involved in both cation exchange with H+, Ca2+, Mg2+ and adsorption-complexation, i.e. fixation of the same equivalent of copper ions and anions (NO3−) without any ion release. The importance of both reactions depends largely on initial copper concentration, peat type and pH. Isotherms of copper (initial concentration ranging between 1 and 20 mM) fixation on two types of peat (eutrophic and oligotrophic peat at 30 g d.w./l at pH ranging between 2 and 4) showed that the higher the initial cupric concentration, the more important is this complexation reaction; over this initial cupric concentration range, ion exchange sites were relatively saturated and reached 308 and 101 mmol/kg d.w. for eutrophic and oligotrophic peat whereas no saturation was found for complexation sites, their capacity attaining up to 74 and 119 mmol/kg d.w., respectively.
The apparent equilibrium constant for ion exchange with acid-treated peat (initial pH 4.0, 30 g d.w./l) for various metal binding on both peat sites ranged between 1.1 and 10.8 in 15 mM metallic solutions. The apparent affinity in batch conditions for 5 elements may be compared according to the apparent global equilibrium constants, ranging between 1.1 × 10−6 and 20.2 × 10−6: Pb > Cu > Ca > Mg, Zn for eutrophic peat and Pb > Ca > Cu > Mg, Zn for oligotrophic peat. 相似文献
212.
In response to the needs of the local authorities, the systematic mapping of zones prone to slope instability was undertaken
for the urban area of Lyons, the second largest city of France with a population of 1.2 million. This involved working within
operational constraints, including the extent of the study sector (some 300 km2 of the 500 km2 covered by the urban area), an accuracy of 1:5,000 scale throughout, difficulties of ground observation in an urban environment
and a limited budget. An original methodology was developed and implemented to deal with these constraints. This combined
automatic mapping methods using GIS (cross-checking slope and geological criteria) with naturalistic assessment methods (visual
analysis). The results obtained met the expectations of the local authorities. After checking, the maps produced were appended
to the regulatory urban planning documents under development.
Electronic Publication 相似文献
213.
Becker S Maissen O Ponomarev I Stoll T Meury T Sprecher C Alini M Wilke I 《Journal of materials science. Materials in medicine》2008,19(2):659-665
We investigated the osteopromotive properties of plasmatransglutaminase (F XIII), bone marrow and venous blood on a resorbable
β-tricalcium phosphate (β-TCP) scaffold. A baseline binding and release study of F XIII from the scaffold showed a continuous
release of 18% of the total dose after 48 h. The main study consisted of 18 adult sheep with cylindrical defects in both tibiae.
The defects were filled with a β-TCP cylinder impregnated either with bone marrow, venous blood, F XIII or sheep were treated
with 1250 IU F XIII intravenously over 14 days (n = 4 in each group). The defects were left open in two sheep. QCT and histology was performed after 6 and 12 weeks. The best
bone ingrowth was seen after 6 weeks in the bone marrow group and after 12 weeks in the local F XIII group. The highest ingrowth
on the inside of the cylinder proving the osteopromoting potential of F XIII was found in the local F XIII group. In our opinion
F XIII is a good and readily available osteopromoting agent which can be used with β-TCP in cases of bone deficit to promote
bone regeneration. 相似文献
214.
Faklaris O Garrot D Joshi V Druon F Boudou JP Sauvage T Georges P Curmi PA Treussart F 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(12):2236-2239
Diamond nanoparticles are promising photoluminescent probes for tracking intracellular processes, due to embedded, perfectly photostable color centers. In this work, the spontaneous internalization of such nanoparticles (diameter 25 nm) in HeLa cancer cells is investigated by confocal microscopy and time-resolved techniques. Nanoparticles are observed inside the cell cytoplasm at the single-particle and single-color-center level, assessed by time-correlation intensity measurements. Improvement of the nanoparticle signal-to-noise ratio inside the cell is achieved using a pulsed-excitation laser and time-resolved detection taking advantage of the long radiative lifetime of the color-center excited state as compared to cell autofluorescence. The internalization pathways are also investigated, with endosomal marking and colocalization analyses. The low colocalization ratio observed proves that nanodiamonds are not trapped in endosomes, a promising result in prospect of drug delivery by these nanoparticles. Low cytotoxicity of these nanoparticles in this cell line is also shown. 相似文献
215.
Thierry Ngangmou Noumo Pierre Desire Mbougueng Leopold Ngoune Tatsadjieu Alphonse Tegang Sokamte Carl Moses Fontum Mbofung 《Sensing and Instrumentation for Food Quality and Safety》2016,10(3):480-492
The present work aimed at evaluating the Cucurbita maxima Duchesne defatted seeds flour (CDSF) as fat replacer in beef patty. Pastes obtained from CDSF containing 60 and 72 % water were prepared and used to replace fat in beef patty at 25, 50, 75 and 100 % respectively. A control patty was processed using kidney fat from beef. The proximate composition, technological yield, textural and sensorial properties of different samples were evaluated. Results showed that CDSF contains 77.76/100 g proteins based on dried matter. Protein content of patty increased with fat substitution rates (FSR) from 18.82/100 g wet matter (WM) to 23.24/100 g WM respectively for the control (P0) and the sample in which fat was substituted at 100 % with the CDSF paste with a water content of 60 % (P460). The lipid content dropped with the increase in the fat substitution rate and water content of CDSF paste from 10.70/100 to 0.28/100 g WM respectively for the sample in which fat was substituted at 25 % with the CDSF paste with a water content of 60 % (P160) and the sample in which fat was substituted at 100 % with the CDSF paste containing 72 % water (P472). Similarly, hardness dropped from 54.78 N (P0) to 37.56 N (P472) respectively. The cooking yield increased significantly (p < 0.05) with the increase in the water content of the CDSF paste and the fat substitution rate. From the sensory analysis, patties with 75 and 100 % of FSR were the most accepted. Thus, the CDSF paste can be used in beef patty as a fat replacer to reduce the detrimental effect of animal fat consumption. 相似文献
216.
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218.
Electrochemical oxidation of 2'-deoxyguanosine has been performed on boron-doped diamond (BDD) electrodes, resulting in a strong adsorption of the formed oxidized products onto the BDD surface. The adsorption behavior has been investigated by studying the electrochemical behavior of a redox probe ([IrCl6]3-) using cyclic voltammetry. The most probable situations are the formation of (A) an insulating adsorbed film resulting in a partially blocked electrode behavior, (B) a porous film, or (C) an overall conductive film. Different parameters such as the standard rate constant, the charge-transfer coefficient, the electrode/adsorbed products/solution interface resistance, and the formal potential of the redox couple were determined. Through comparison of theoretical current-potential curves obtained by analytical calculations with experimental cyclic voltammograms, we found that the oxidized products of 2'-deoxyguanosine form a continuous conductive film on BDD. 相似文献
219.
Thierry Tran Cosette Grandvalet Franois Verdier Antoine Martin Herv Alexandre Raphaëlle Tourdot‐Marchal 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):2050-2070
Kombucha is a beverage made from sugared tea transformed by yeasts and acetic acid bacteria. Being originally homemade, it has become an industrially produced soft drink whose quality standards are poorly defined and whose production process is still not fully controlled. Based on current knowledge in beverages, links between kombucha's chemical composition and sensorial compounds are drawn. Macromolecules create turbidity, whereas uncharacterized tea pigments derivatives participate in the color. Residual sugars bring sweetness and organic acids produced by acetic acid bacteria form its characteristic sour taste. Acetic acid is also part of its aroma profile, although little data are available on the smell of kombucha. Carbon dioxide, potentially polyphenols, and residual ethanol are involved in the mouthfeel. In this review, after defining the key compounds that shape the characteristic sensory properties of kombucha, the impact of different production parameters is discussed. Water composition is determinant in the extraction of tea compounds along with the tea type and infusion duration and temperature. The type and amount of sweeteners play a role in the sweetness and influences the production kinetics. Similarly, the amount of inoculum and its microbial composition have an effect on the production, but the role of the vessels' geometry and temperature are also essential parameters that can be used to adjust the acidification phase's duration. Despite the amount of research carried out, further investigations of kombucha's sensory characteristics are needed. Such research could lead to a better definition of kombucha's quality and to an improved control over its production process. 相似文献
220.
Thierry Schneider 《辐射防护》2023,43(1):1-10
自2007年国际放射防护委员会(ICRP)发布一般性建议以来,在解决将这些建议付诸实践所面临的挑战方面取得了一些进展。值得注意的是,为放射防护管理而提出三类照射情况后(即,计划照射、现存照射及应急照射),我们进一步研究了它们在几个领域的应用,如涉及天然放射性物质的工业领域以及核事故发生后的应急与恢复领域。本文着重介绍了最近一些出版物提出的以及持续开展的工作中所涉及的主要问题,重点围绕与放射防护体系伦理基础有关的研究进展、放射防护体系在管理现存照射情况中的应用以及环境放射防护与ICRP防护体系的融合。最后,本文介绍了2022年ICRP成立的与放射防护体系应用相关的新工作组的工作目标。 相似文献