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91.
92.
Patricia M. Cooney C. D. Evans A. W. Schwab J. C. Cowan 《Journal of the American Oil Chemists' Society》1958,35(4):152-156
Summary Metal-inactivating agents, such as citric acid, sorbitol, lecithin, and carboxymethylmercapto succinic acid, are not active
in unheated vegetable oils. Apparently trace metals present in normal glyceride oils are held within a complex of unknown
structure. After heating an oil, the metals can be complexed by metal-inactivating agents, such as citric acid. The release
of metals appears to be associated closely with the breakdown of the fatty acid hydroperoxides. Formation of some association
or complex between the metal and the hydroperoxide group or between the metal and the unsaturated linkage of the fatty hydroperoxide
is suggested. The metals are held very tenaciously within this unknown structure. Although the metal is not available as an
uncomplexed metallic ion, it does behave as a very strong pro-oxidant catalyst. The application of heat releases the metal
so it can be complexed by added metal inactivators.
Pressented at spring meeting, American Oil Chemists’ Society, New Orleans, La., April 18–20, 1955. 相似文献
93.
A. W. Schwab Patricia M. Cooney C. D. Evans J. C. Cowan 《Journal of the American Oil Chemists' Society》1953,30(5):177-182
Summary Metal deactivating agents containing nitrogen as the coordinating atom have been developed for use in edible oils. The most
effective compounds were those containing two carboxyl groups, α,α′ to the nitrogen. Those containing β,β′ carboxyls were
less effective, and the efficiency of α,β carboxyls was intermediate. The activity is explained on the basis of the formation
of metal chelation rings—complexes believed to be typical Werner's coordination complexes. The nitrogen atom may be an amine
or a cyclic nitrogen. Complex coordination compounds can also be formed from acidic nitrogen compounds, such as hydroxamic
acids, when the proper structure for metal chelation exists.
Chelidamic acid has been found to be a very efficient metal deactivating agent for both copper and iron. Imino α or β dicarboxylic
acids show varying degrees of effectiveness toward the complexing of iron and copper. The greater the number of 5-membered
chelation rings that are possible around the metal atom, the greater is the observed stability.
This paper is based on work submitted by A. W. Schwab in partial fulfillment of the requirements for the Ph.D. Degree at Bradley
University, Peoria, Ill. Presented at fall meeting of American Oil Chemists' Society, October 20–22, 1952, in Cincinnati,
O.
One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S.
Department of Agriculture. 相似文献
94.
Thermally Reduced Graphene Oxide Nanohybrids of Chiral Functional Naphthalenediimides for Prostate Cancer Cells Bioimaging 下载免费PDF全文
James A. Tyson Vincenzo Mirabello David G. Calatayud Haobo Ge Gabriele Kociok‐Köhn Stanley W. Botchway G. Dan Pantoş Sofia I. Pascu 《Advanced functional materials》2016,26(31):5641-5657
This study reports on the supramolecular assemblies formed between planar carbon systems (PCSs) such as thermally reduced graphene oxide (TRGO) and its small‐molecule model system coronene and a series of d ‐ and l ‐α amino acid derivatized naphthalenediimides (NDIs) where the halogen substituents (X = F, Cl, Br, I) are varied systematically. Confocal fluorescence microscopy of NDIs, NDI?coronene, and NDI?TRGO complexes is performed proving the uptake and stability of such complexes in the cellular environment and suggesting their potential as prostate cancer imaging agents. 1H NMR and UV–vis spectroscopy studies support the formation of charge transfer complexes whereby the increasing polarizability and general electronegativity of the aryl halide substituted at the NDI periphery influence the magnitude of the association constants in the ground state between NDI and coronene. Complexation between NDIs and PCSs also results in stable photoexcited assemblies within the solution (coronene) as well as the dispersed phased (TRGO). Fluorescence emission titrations and 2‐photon time correlated single photon counting measurements suggest the existence of dynamic quenching mechanisms upon the excitation of the fluorophore in the presence of the carbon substrates, as these methods are sensitive proves for the subtle changes in the NDI environment. The series of halogenated species used exerts supramolecular control over the degree of surface assembly on the TRGO and over the interactions with the coronene molecule, and this is of relevance to the assembly of future biosensing platforms as these materials can both be viewed as congeners of graphene. Finally, MTT assays carried out in PC‐3 cells demonstrate that the stable noncovalent functionalization of TRGO and coronene with either l or d NDIs remarkably improves the cellular viability in the presence of such graphene‐like materials. These phenomena are of particular relevance for the understanding of the direct donor–acceptor interactions in solutions which govern the design of nanomaterials with future biosensing and bioimaging applications. 相似文献
95.
Chun Chen William T. Baumann Jianhua Xing Lingling Xu Robert Clarke John J. Tyson 《Journal of the Royal Society Interface》2014,11(96)
Endocrine therapy, targeting the oestrogen receptor pathway, is the most common treatment for oestrogen receptor-positive breast cancers. Unfortunately, these tumours frequently develop resistance to endocrine therapies. Among the strategies to treat resistant tumours are sequential treatment (in which second-line drugs are used to gain additional responses) and intermittent treatment (in which a ‘drug holiday’ is imposed between treatments). To gain a more rigorous understanding of the mechanisms underlying these strategies, we present a mathematical model that captures the transitions among three different, experimentally observed, oestrogen-sensitivity phenotypes in breast cancer (sensitive, hypersensitive and independent). To provide a global view of the transitions between these phenotypes, we compute the potential landscape associated with the model. We show how this oestrogen response landscape can be reshaped by population selection, which is a crucial force in promoting acquired resistance. Techniques from statistical physics are used to create a population-level state-transition model from the cellular-level model. We then illustrate how this population-level model can be used to analyse and optimize sequential and intermittent oestrogen-deprivation protocols for breast cancer. The approach used in this study is general and can also be applied to investigate treatment strategies for other types of cancer. 相似文献
96.
C. D. Evans E. N. Frankel Patricia M. Cooney Helen A. Moser 《Journal of the American Oil Chemists' Society》1960,37(9):452-456
Summary Oxidation prior to deodorization was shown to be detrimental to the flavor and oxidative stability of soybean oil. The increase
in the nonvolatile carbonyl content of freshly deodorized oils was proportional to the peroxide value of the oils before deodorization.
Rate of loss of flavor and oxidative stability of the oil were related to the extent of carbonyl development. All oils, whether
or not they had been submitted to any known oxidation, contained some nonvolatile carbonyls. The loss in stability was not
due to a loss of the antioxidant tocopherol.
Oxidized soybean oil methyl esters were shown to develop nonvolatile carbonyl compounds upon heating at deodorization temperatures.
The addition of isolated methyl ester peroxide decomposition products to deodorized soybean oil reduced its flavor and oxidative
stability in proportion to the amount added. The results obtained were parallel and similar to those obtained by oxidizing
soybean oil prior to deodorization.
Flavor deterioration and undesirable flavors were typical of aging soybean oil whether or not the oils were oxidized before
deodorization or whether an equivalent amount of nonvolatile thermal decomposition products was added to the oil. These oxidatively
derived, nonvolatile carbonyl materials are believed to enter into the sequence of reactions that contribute to flavor instability
and quality deterioration of soybean oil. The structure of these materials is not know.
This work indicates the importance of minimizing autoxidation in soybean oil particularly before deodorization to insure good
oxidative and flavor stability.
Presented at fall meeting, American Oil Chemists’ Society, October 20–22, 1958, Chicago, Ill.
This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department
of Agriculture. 相似文献
97.
Cooney CM 《Environmental science & technology》2006,40(4):1091-1092
98.
99.
100.
Jidong KANG James A. GIANETTO William R. TYSON 《Frontiers of Mechanical Engineering》2018,13(4):546-553
Fracture toughness measurement is an integral part of structural integrity assessment of pipelines. Traditionally, a single-edge-notched bend (SE(B)) specimen with a deep crack is recommended in many existing pipeline structural integrity assessment procedures. Such a test provides high constraint and therefore conservative fracture toughness results. However, for girth welds in service, defects are usually subjected to primarily tensile loading where the constraint is usually much lower than in the three-point bend case. Moreover, there is increasing use of strain-based design of pipelines that allows applied strains above yield. Low-constraint toughness tests represent more realistic loading conditions for girth weld defects, and the corresponding increased toughness can minimize unnecessary conservatism in assessments. In this review, we present recent developments in low-constraint fracture toughness testing, specifically using single-edge-notched tension specimens, SENT or SE(T). We focus our review on the test procedure development and automation, round-robin test results and some common concerns such as the effect of crack tip, crack size monitoring techniques, and testing at low temperatures. Examples are also given of the integration of fracture toughness data from SE(T) tests into structural integrity assessment. 相似文献