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排序方式: 共有1174条查询结果,搜索用时 31 毫秒
161.
AxelG. Griesbeck Mathias Schfer Johannes Uhlig 《Advanced Synthesis \u0026amp; Catalysis》2008,350(13):2104-2108
Polar meso‐tetraarylporphyrins 2 – 4 were synthesized from tetrakis‐4‐hydroxyphenylporphyrin 1 as the central building block by consecutive base‐induced reactions with glycidol. The decorating units form a polar hydrogen‐bonded shell around the sensitizer core which is proposed as the binding site for polar substrates in photocatalyzed oxygenation reactions. As substrate, the polarity‐sensor mesitylol ( 5 ) was applied and the reaction constrained in a polystyrene matrix. Increasing shell dimensions lead to increased diastereoselectivities for the allylic hydroperoxides 6 and thus clearly demonstrate the concept of shell‐induced substrate stereoselectivity in singlet oxygen reactions. 相似文献
162.
Stefan Panglisch Arman Kouchaki Shalmani Martin Weber Oliver Gronwald Peter Berg Martin Heijnen Michaela Krug Marcel Koti Andreas Nahrstedt Volker Abetz Ulrich A. Handge Lara Grünig Mathias Ulbricht Inga Stratmann 《化学,工程师,技术》2019,91(8):1162-1167
Within the framework of the MABMEM research project, new high‐performance membranes are being developed for sustainable water management. The performance of the membranes will be evaluated in comparative and standardized fouling tests as well as in terms of the removal of trace impurities on a laboratory scale. Seven candidates are currently being tested in demonstrator trials with real‐water matrix in a waterworks for the direct treatment of dam water without prior coagulation over a period of 6 months. Subsequently, the new membrane materials will be operated with the effluent of a wastewater treatment plant. 相似文献
163.
Robert Riedl Nicole Dünzer Maximilian Michel Fritz Jacob Mathias Hutzler 《Journal of the Institute of Brewing》2019,125(2):250-260
Lactobacillus brevis is the most significant beer spoilage bacteria worldwide. It is found as a contaminant at all stages of brewing, including during primary and secondary fermentation, storage, filtration and the packaging process. In production with flash pasteurisation and subsequent hygienic filling, avoiding and tracing secondary contaminations is the key to a microbiologically stable product. However, L. brevis strains vary in their spoilage potential and can grow in many different beer types. This study presents a physiological test scheme for growth potential and biofilm formation in various media. It was determined that a large number of L. brevis strains can form biofilms as a first coloniser. The identification of the species alone is therefore not enough to be sure of the spoilage risk, which shows the need for a more in depth differentiation. DNA fingerprint techniques are crucial to differentiate isolates of this species at strain level. The rep‐PCR fingerprint system (GTG)5 was used to differentiate a selected collection of 20 isolates, which were characterised in growth and biofilm formation in various media. The data showed a high variation within the selected isolates. As second step, generated fingerprint clusters of L. brevis were traced back to contamination sources in a German brewery, revealing a high number of isolates with potentially varying growth, spoilage and biofilm potential. L. brevis being the demonstrator species, the PCR system used is a powerful and compatible tracing and troubleshooting tool for all kinds of spoilage bacteria in the brewing industry. © 2019 The Institute of Brewing & Distilling 相似文献
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165.
Thixoforging allows one-step forming processes of near-net shape components having excellent mechanical properties. However, the high sensitivity of thixoforging regarding process conditions requires precise modelling and determination of process related parameters. At the same time, simple numerical design proves challenging because of the inaccuracy of existing one-phase material models regarding the shear thinning flow behaviour of semi solid metals. Consequently, this paper deals with the development of a new one-phase material model providing a more precise simulation of materials’ shear rate dependency. By using this model, simulations could be performed, which allowed the prediction of solidification and flow-related component defects. 相似文献
166.
Maximilian Michel Sandro Cocuzza Martin Biendl Frank Peifer Sebastian Hans Yvonne Methner Friedrich Pehl Werner Back Fritz Jacob Mathias Hutzler 《Journal of the Institute of Brewing》2020,126(4):354-361
Beer spoiling lactic acid bacteria are a major reason for quality complaints in breweries around the world. Spoilage by a variety of these bacteria can result in haze, sediment, slime, off-flavours and acidity. As these bacteria occur frequently in the brewing environment, using certain hop products that inhibit the growth of these spoilers could be a solution to prevent problems. To investigate the impact of seven different hop compounds (α-acids, iso-α-acids, tetrahydro-iso-α-acids, rho-iso-α-acids, xanthohumol, iso-xanthohumol and humulinones) on the growth of six major beer spoilage bacteria (Lactobacillus brevis. L. backi, L. coryniformis, L. lindneri, L. buchneri, Pediococcus damnosous), two concentrations (10 and 25 mg/L) of each hop substance were added to unhopped beer. The potential growth of the spoilage bacteria was investigated over 56 consecutive days. A comparison of the results shows a strong inhibition of growth of all spoilage bacteria at 25 mg/L of tetrahydro-iso-α-acids closely followed by α-acids as the second most inhibitory substance. The results showed a high resistance of L. brevis to all hop compounds as well as an inhibition of L. coryniformis and L. buchneri at low concentrations of most hop components. In comparison with the control sample, L. lindneri showed increased growth in the presence of some hop compounds (rho-iso-α-acids, xanthohumol, iso-xanthohumol, humulinones). © 2020 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling 相似文献
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168.
Thiago Rocha dos Santos Mathias Vernica Marinho Fontes Alexandre Magali Christe Cammarota Pedro Paulo Moretzsohn de Mello Eliana Flvia Camporese Srvulo 《Journal of the Institute of Brewing》2015,121(3):400-404
Agro‐industrial wastes are produced in large quantities around the world from the processing and manufacturing of food and beverages. The disposal of these wastes into the environment leads to damage to ecosystems owing to their composition rich in organic matter. In this context it may be noted that the brewing industry, whose production process includes processing steps and fermentation of vegetable raw materials such as barley and/or other grains used as adjuncts and hops, generates various byproducts. The worldwide consumption of these beverages and the current model of breweries, which includes production on a large scale, lead to the generation of large amounts of brewery waste, namely spent grain, hot trub and residual yeast. Owing to its composition, these residues exhibit significant potential for application in bioprocess technologies. In this study the three residues mentioned had their composition determined as a function of moisture, ash, total organic carbon (TOC), total and soluble nitrogen, reducing sugar and soluble free amino nitrogen. Moreover, the residues were characterized for total acidity, pH and chemical oxygen demand (COD) of total and soluble fractions. The three residues evaluated had high moisture content (>80%) and high organic matter content (TOC and COD, ~50% and >1000 mg/g, respectively), which can highlights the significant protein fraction (almost 50% for hot trub and residual yeast), suggesting the possibility of using these wastes for recovery. Copyright © 2015 The Institute of Brewing & Distilling 相似文献
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170.
De Oliveira PR Bechara GH Denardi SE Oliveira RJ Mathias MI 《Microscopy research and technique》2012,75(1):28-35
In the present study, mice livers were examined following exposure to different doses of fipronil (15, 25, and 50 mg/kg). Histological and histochemical techniques were used to determine the cytotoxic potential of this compound and to assess the damage it caused to livers. Mice were divided into four groups: control group and groups I, II, and III were exposed to 15, 25, and 50 mg/kg fipronil, respectively. Our findings revealed cytological, morphohistological, and histochemical alterations in liver cells of animals from groups I, II, and III compared to group control animals. These changes included Kupffer-cell proliferation, hepatocyte hypertrophy, accumulation and distribution of proteins, polysaccharides, lipids, and vacuoles in the cytoplasm of hepatocytes, and congestion of blood vessels. These phenotypes mainly characterize the following: (a) autophagic processes, (b) steatosis, and (c) cell death by necrosis, which demonstrate the damage caused by fipronil on nontarget organisms in artificial conditions. 相似文献