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81.
82.
The carbonyl group concentration was determined with C-14 labelled 2,4-dinitrophenylhydrazine in the following substances: pergamin, filterpaper, cellophane, polyethylene and polypropylen. For standardizing the method, the MALAPRADE-splitting of the C2? C3-bond in the glucosidic unit of celluloses was used. The reactivity towards NaJO4 increased in the following way: cellophane < filterpaper < pergamin.  相似文献   
83.
Global folding of proteins using a limited number of distance constraints   总被引:1,自引:0,他引:1  
A Monte Carlo method is presented which can obtain the correcttertiary fold of a protein given the secondary structure andas few as three interactions between each secondary structureunit. This method was used to fold hemerythrin, Qavodoxin, bovinepancreatic trypsin inhibitor and a variable light domain froman immunoglobulin using the known secondary structures of theseproteins. Each of the proteins was successfully folded to obtaina structure resembling the initial X-ray structure. Reasonablesuccess was also achieved when using a secondary structure predictionalgorithm to assign secondary structure. The r.m.s. deviationsbetween the folded proteins and the crystal structures are inthe order of 3–5 A for the backbone coordinates. Evaluationof the r.m.s. deviations between members of the globin familyindicates that two equivalent overall folds may have r.m.s.deviations of this or even larger magnitude. The limiting numberof constraints necesssary to achieve the correct fold is discussed.  相似文献   
84.
Software development teams use test suites to test changes to their source code. In many situations, the test suites are so large that executing every test for every source code change is infeasible, due to time and resource constraints. Development teams need to prioritize their test suite so that as many distinct faults as possible are detected early in the execution of the test suite. We consider the problem of static black-box test case prioritization (TCP), where test suites are prioritized without the availability of the source code of the system under test (SUT). We propose a new static black-box TCP technique that represents test cases using a previously unused data source in the test suite: the linguistic data of the test cases, i.e., their identifier names, comments, and string literals. Our technique applies a text analysis algorithm called topic modeling to the linguistic data to approximate the functionality of each test case, allowing our technique to give high priority to test cases that test different functionalities of the SUT. We compare our proposed technique with existing static black-box TCP techniques in a case study of multiple real-world open source systems: several versions of Apache Ant and Apache Derby. We find that our static black-box TCP technique outperforms existing static black-box TCP techniques, and has comparable or better performance than two existing execution-based TCP techniques. Static black-box TCP methods are widely applicable because the only input they require is the source code of the test cases themselves. This contrasts with other TCP techniques which require access to the SUT runtime behavior, to the SUT specification models, or to the SUT source code.  相似文献   
85.
86.
    
In this paper, we present efficient algorithms for the inversion of a triangular matrix on different interconnection networks. For hypercubes, we describe an elegant straightforward implementation of L. Csansky's well known PRAM algorithm [Ph.D. dissertation, Computer Sci. Div., Univ. of California, Berkeley 1974]. The time complexity is(log2n) usingn3processors, i.e., within the same order as the PRAM algorithm. Moreover, we give a general approach for the design of triangular matrix inversion algorithms on a large class of networks. Applied to some of these networks, as, e.g., the de Bruijn network, the shuffle-exchange network, and the cube-connected-cycles, this approach yields triangular matrix inversion algorithms that meet the PRAM complexity bounds of the problem within a small constant.  相似文献   
87.
    
Zusammenfassung Über Zimthochdruckextrakte, die neuerdings zunehmend im Handel anzutreffen sind, liegen im Gegensatz zu Zimtölen bisher fast keine Literaturangaben vor. Mittels HPLC wurden daher handelsübliche Zimtrinden-CO2-Hochdruckextrakte vonCinnamomum zeylanicum (Ceylon- und Madagaskar-Zimt),C. cassia (Chinesischer Zimt) undC. burmanii (Padang-Zimt) im Vergleich mit Zimtölen untersucht. Dabei zeigte sich, daß die relevanten Inhaltsstoffe abhängig von der Zimtart einerseits und der Probenart andererseits in unterschiedlichen, charakteristischen Konzentrationen vorlagen, wobei sich nicht nur Öle und Hochdruckextrakte, sondern auch sog. Selektivextrakte (40°C/90 bar) und Totalextrakte (40°C/ 280–300 bar) deutlich voneinander unterschieden.
HPLC analysis of supercritical CO2 cinnamon and cassia extracts in comparison with cinnamon and cassia oils
Nowadays supercritical CO2 extracts of cinnamon and cassia are coming more and more in trade. Contrary to cinnamon and cassia oils there are very few references in literature about these. Commercially available supercritical CO2 extracts of cinnamon and cassia barks (cinnamon type Ceylon and type Madagascar, cassia type China and type Indonesia) were analysed by HPLC and compared with cinnamon and cassia oils. The results of the analysis showed that the main compounds evidently differed depending on the species of cinnamon (Cinnamomum zeylanicum, C. cassia andC. burmanii) and on the kind of sample, whereby there was a great difference not only between oils and CO2 extracts, but also between so-called selective extracts (40°C/90 bar) and total extracts (40°/280–300 bar).
  相似文献   
88.
Time-domain nuclear magnetic resonance (TD-NMR) is widely used within food industries for QC/QA applications. Precise determination of moisture and water is of fundamental interest. To determine moisture and water in the presence of lipids, the minispec makes use of differences in their respective NMR relaxation properties. The minispec applications analysing bound water are well-known and have become International standard methods. Different methods to analyse food samples with high water content or free water, like some dairy products, are addressed in this paper. Explicitly, the well-known pre-drying methods are compared to NMR diffusion experiments and a combined relaxation time analysis. Finally the single-sided NMR approach is discussed to analyse packages food.  相似文献   
89.
    
Amyloid fibrils formed by the α‐Synuclein (α‐Syn) protein are the pathological hallmark of multiple human disorders, generally termed α‐synucleinopathies. The aggregation process of α‐Syn into amyloids appears to be highly dependent on the presence of: i) hydrophobic–hydrophilic interfaces, and ii) pre‐formed seed fibrils. By combining Thioflavin T binding measurements with different microscopy techniques (direct stochastic optical reconstruction microscopy, atomic force microscopy, correlative super‐resolution light microscopy, and scanning electron microscopy), the effect of the air–water interface (AWI) is tested on seeded α‐Syn aggregation. The correlation of the results provided by each method reveals striking differences in the mechanism of formation, yield, length, thickness, and morphology of fibrils obtained from samples having equal initial amounts of seeds and monomers, but incubated in the presence or absence of an AWI. Overall, the results indicate that the AWI determines how amyloids grow and proliferate, the final balance between monomer and aggregates, and the morphological properties of the aggregates themselves. These observations may set the basis for amplifying and tuning the properties of specific fibril polymorphs of interest, in structural biology and cytotoxicity studies, as well as in those materials science applications featuring amyloids.  相似文献   
90.
    
BACKGROUND: Phenol and hexavalent chromium are considered industrial pollutants that pose severe threats to human health and the environment. The two pollutants can be found together in aquatic environments originating from mixed discharges of many industrial processes, or from a single industry discharge. The main objective of this work was to study the feasibility of using phenol as an electron donor for Cr(VI) reduction, thus achieving the simultaneous biological removal/reduction of the two pollutants in a packed‐bed reactor. RESULTS: A pilot‐scale packed‐bed reactor was used to estimate phenol removal with simultaneous Cr(VI) reduction through biological mechanisms, using a new mixed bacterial culture originated from Cr(VI)‐reducing and phenol‐degrading bacteria, operated in draw–fill mode with recirculation. Experiments were performed for feed Cr(VI) concentration of about 5.5 mg L?1, while phenol concentration ranged from 350 to 1500 mg L?1. The maximum reduction/removal rates achieved were 0.062 g Cr(VI) L?1 d?1 and 3.574 g phenol L?1 d?1, for a phenol concentration of 500 mg L?1. CONCLUSION: Phenol removal with simultaneous biological Cr(VI) reduction is feasible in a packed‐bed attached growth bioreactor. Phenol was found to inhibit Cr(VI) reduction, while phenol removal was rather unaffected by Cr(VI) concentration increase. However, the recorded removal rates of phenol and Cr(VI) were found to be much lower than those obtained from previous research, where the two pollutants were examined separately. Copyright © 2008 Society of Chemical Industry  相似文献   
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