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排序方式: 共有1516条查询结果,搜索用时 31 毫秒
991.
Andro Mondala Rafael Hernandez Todd French Linda McFarland Darrell Sparks William Holmes Monica Haque 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(1):33-41
BACKGROUND: The effect of acetic acid, a lignocellulose hydrolysis by‐product, on lipid accumulation by activated sludge cultures grown on glucose was investigated. This was done to assess the possible application of lignocellulose as low‐cost and renewable fermentation substrates for biofuel feedstock production. RESULTS: Biomass yield was reduced by around 54% at a 2 g L?1 acetic acid dosage but was increased by around 18% at 10 g L?1 acetic acid dosage relative to the control run. The final gravimetric lipid contents at 2 and 10 g L?1 acetic acid levels were 12.5 ± 0.7% and 8.8 ± 3.2% w/w, respectively, which were lower than the control (17.8 ± 2.8% w/w). However, biodiesel yields from activated sludge grown with acetic acid (5.6 ± 0.6% w/w for 2 g L?1 acetic acid and 4.2 ± 3.0% w/w for 10 g L?1 acetic acid) were higher than in raw activated sludge (1–2% w/w). The fatty acid profiles of the accumulated lipids were similar with conventional plant oil biodiesel feedstocks. CONCLUSIONS: Acetic acid enhanced biomass production by activated sludge at high levels but reduced lipid production. Further studies are needed to enhance acetic acid utilization by activated sludge microorganisms for lipid biosynthesis. Copyright © 2011 Society of Chemical Industry 相似文献
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995.
Gianluca Bella Monica Barbero Fabrizio Barpi Mauro Borri-Brunetto Daniele Peila 《岩石力学与岩土工程学报(英文版)》2017,9(2):247-259
The paper presents a new prefabricated bio-engineering structure for the support of unstable soil. This prefabricated structure is made of a steel frame which is completely filled with soil and a face made of tree trunks among which scions or autochthonous bushes are planted. Due to the difficulties in interpreting the complex interaction between soil and structure during the installation and lifetime, an in situ test was carried out in order to evaluate the state of stress in the steel frame and to understand the global behavior of the structure under service loads. On the basis of the obtained results, a procedure for checking the structure safety was proposed and discussed. An easy design method was developed during the research. Moreover, the use of this type of prefabricated structure shows several advantages, such as good performances in terms of stabilizing effects, and easy assembly and transport. 相似文献
996.
Valeria Belvedere Francesco Cuttaia Monica Rossi Luca Stringhetti 《International Journal of Project Management》2019,37(3):410-424
Lean Product Development (LPD) is suggested as an approach that can reduce waste in projects aimed at developing technically complex items, which typically present substantial uncertainty about their output, as well as higher costs and longer development times. However, how can LPD be implemented in complex projects, where some redundancies in the development process are considered necessary in order to guarantee the quality of the final outcome? This paper answers this question, through a survey conducted at INAF, the Italian Institute of Astrophysics, that runs complex projects. The evidence shows that complex projects can actually be affected by the types of waste reported in LPD literature. Still, researchers may fail to determine the real priorities of intervention as they have trouble distinguishing between value-adding and value-destroying activities. Furthermore, they do not perceive the relevance of addressing the wastes generated by their own work; on the contrary, they place considerable attention on inefficiencies that are beyond the scope of their direct responsibilities. Recommendations to overcome this problem are proposed. 相似文献
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Matteo Bordiga Rosa Perestrelo José S. Câmara Qiong-Qiong Yang Harold Corke Fabiano Travaglia Monica Locatelli Marco Arlorio Jean Daniel Coïsson 《International Journal of Food Science & Technology》2021,56(4):1551-1561
The global volatile signature of Vespolina wines from different vintages was established using solid-phase microextraction combined with gas chromatography–mass spectrometry (HS-SPME/GC-qMS). Wines were also characterised in terms of bioactive compounds (such as individual polyphenols, biogenic amines and their precursors) by high-performance liquid chromatography (RP-HPLC). In addition, some physicochemical parameters, such as the total phenolic content, total tannins and antioxidant capacity, were evaluated. Seventy-one volatile compounds and thirty-three bioactive compounds were identified in Vespolina wines. The application of multivariate analysis to the obtained data revealed that 2-phenylethyl acetate, ethyl nonanoate, 2-hexanol, isoamyl octanoate and ethyl 2-hydroxymethylbutanoate were the primary compounds responsible for Vespolina wines classification, mainly indicative for wines of 2015 and 2013 vintages. Conversely, wines from 2008 and 2009 vintages showed highest values of procyanidin B1, catechin, gallic acid, trans-piceid and trans-resveratrol. 相似文献
999.
Valentina Peruzzo Matteo Andrea Chiurato Monica Favaro Patrizia Tomasin 《Mass spectrometry reviews》2018,37(1):22-42
Metal alkoxides are metal‐organic compounds characterized by the presence of M?O?C bonds (M = metal). Their chemistry seems to be, in principle, relatively simple but the number of possible reactant species arising as a consequence of their behavior is very remarkable. The physico‐chemical properties of metal alkoxides are determined by many different parameters, the most important ones being the electronegativity of the metal, the ramification of the ligand, and the acidity of the corresponding alcohol. Their reactivity makes them suitable and versatile candidates for many applications, including homogeneous catalysis, synthesis of new ceramic materials through the sol‐gel process and, recently, also for Cultural Heritage. Metal alkoxides are characterized by a strong tendency to give clusters and/or oligomers through oxo‐bridges. Mass spectrometry has been successfully employed for the characterization of metal alkoxides in the gas‐phase. Electron ionization (EI) allowed the assessment of the molecular weight and of the most relevant decomposition pathways giving information on the relative bond strength of differently substituted molecules. On the other hand, information on the reactivity in solution of these molecules have been obtained by electrospray ionization (ESI)‐matrix assisted laser desorption ionization (MALDI) experiments performed on their reaction products. These data were relevant to investigate the sol‐gel process. In this review, these aspects are described and the results obtained are critically evaluated. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 相似文献
1000.
Silvia A. V. Tfouni Camila S. Serrate Larissa B. Carreiro Monica C. R. Camargo Camila R. A. Teles Kátia M. V. A. B. Cipolli Regina P. Z. Furlani 《International Journal of Food Science & Technology》2012,47(2):406-415
During coffee roasting process, several substances may be formed or eliminated. The influence of roasting on polycyclic aromatic hydrocarbons (PAHs), caffeoylquinic acids (CQAs) and caffeine levels was studied in Coffea arabica cv. Catuaí Amarelo IAC‐62 and Coffea canephora cv. Apoatã IAC‐2258, roasted in three roasting degrees. CQAs and caffeine were determined simultaneously by HPLC‐DAD, and PAHs by HPLC‐FLD. Caffeine levels were higher in canephora (1486–1884 mg per 100 g) than in arabica (1110–1255 mg per 100 g) and increased up to 21% at darker roasts. Summed CQA levels were higher in green coffee (4661 and 4946 mg per 100 g) and decreased at darker roasts (234 and 377 mg per 100 g), showing no difference between the coffee cultivars studied. PAH summed levels varied from 0.052 to 0.814 μg kg?1 (arabica) and 0.108 to 0.392 μg kg?1 (canephora). No correlation was observed between roasting degree, coffee cultivar and PAH levels. Results were also analysed using hierarchical cluster analysis and principal component analysis. 相似文献