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61.
The stereochemical features displayed by the N-glycosidic linkagein crystalline N-linked glycoproteins are analyzed. From thestatistical analysis of 44 different glycosylation sites belongingto 26 glycoproteins of the Brookhaven Protein Data Bank, a meanstandard geometry for the GlcNAc moiety, along with a rationalizationof its confornia-tional behavior, can be proposed. As for theglycopeptide linkage, the distribution of observed conformationshas been analyzed on the basis of molecular mechanics calculations.The rotamer distribution of the Asn side chains conforms tothat observed on non-glycosylated structures, and it agreeswith the pattern of flexible conformations gathered from NMRmeasurements. In characterizing the protein-glycan interactions,some hydrogen bonds occur. Stacking between the amphiphilicmoiety of the glycan and some surrounding aromatic, or at leasthydrophobic, amino acid residues is also found. When lookingat the secondary structure of the glycosylated peptide, only25% of the glycosylation sites correspond to situations whereAsn is located at the top of a ß-turn. Other typesof secondary structure exist which fulfil the spatial requirementof having the glycan exposed at the surface of the protein.These data can be compared with the most recent studies on thepeptide conformation which would be required for glycosylation. 相似文献
62.
Serge Abiteboul Omar Benjelloun Tova Milo 《The VLDB Journal The International Journal on Very Large Data Bases》2008,17(5):1019-1040
This paper provides an overview of the Active XML project developed at INRIA over the past five years. Active XML (AXML, for
short), is a declarative framework that harnesses Web services for distributed data management, and is put to work in a peer-to-peer
architecture. The model is based on AXML documents, which are XML documents that may contain embedded calls to Web services, and on AXML services, which are Web services capable of exchanging AXML documents. An AXML peer is a repository of AXML documents that acts both as a client by invoking the embedded service calls, and as a server by providing
AXML services, which are generally defined as queries or updates over the persistent AXML documents. The approach gracefully
combines stored information with data defined in an intensional manner as well as dynamic information. This simple, rather
classical idea leads to a number of technically challenging problems, both theoretical and practical. In this paper, we describe
and motivate the AXML model and language, overview the research results obtained in the course of the project, and show how
all the pieces come together in our implementation.
The first and third authors were partially funded by the European Project Edos. Work done when the second and third authors
were at INRIA.
Work done when the second and third authors were at INRIA. 相似文献
63.
Serge Leimanis Sandrine Hamels Florence Nazé Guillaume Mbongolo Mbella Myriam Sneyers Rupert Hochegger Hermann Broll Lillian Roth Klára Dallmann Adrienn Micsinai José Luis La Paz Maria Pla Claudia Brünen-Nieweler Nina Papazova Isabel Taverniers Norbert Hess Britta Kirschneit Yves Bertheau Colette Audeon Valérie Laval Ulrich Busch Sven Pecoraro Katrin Neumann Sibylle Rösel Jeroen van Dijk Esther Kok Gianni Bellocchi Nicoletta Foti Marco Mazzara William Moens José Remacle Guy Van Den Eede 《European Food Research and Technology》2008,227(6):1621-1632
A new screening method for the detection and identification of GMO, based on the use of multiplex PCR followed by microarray, has been developed and is presented. The technology is based on the identification of quite ubiquitous GMO genetic target elements first amplified by PCR, followed by direct hybridisation of the amplicons on a predefined microarray (DualChip® GMO, Eppendorf, Germany). The validation was performed within the framework of a European project (Co-Extra, contract no 007158) and in collaboration with 12 laboratories specialised in GMO detection. The present study reports the strategy and the results of an ISO complying validation of the method carried out through an inter-laboratory study. Sets of blind samples were provided consisting of DNA reference materials covering all the elements detectable by specific probes present on the array. The GMO concentrations varied from 1% down to 0.045%. In addition, a mixture of two GMO events (0.1% RRS diluted in 100% TOPAS19/2) was incorporated in the study to test the robustness of the assay in extreme conditions. Data were processed according to ISO 5725 standard. The method was evaluated with predefined performance criteria with respect to the EC CRL method acceptance criteria. The overall method performance met the acceptance criteria; in particular, the results showed that the method is suitable for the detection of the different target elements at 0.1% concentration of GMO with a 95% accuracy rate. This collaborative trial showed that the method can be considered as fit for the purpose of screening with respect to its intra- and inter-laboratory accuracy. The results demonstrated the validity of combining multiplex PCR with array detection as provided by the DualChip® GMO (Eppendorf, Germany) for the screening of GMO. The results showed that the technology is robust, practical and suitable as a screening tool. 相似文献
64.
Raoudha Haddad Michael Holzinger Reynaldo Villalonga Astrid Neumann Jaan Roots A. Maaref Serge Cosnier 《Carbon》2011,(7):2571-2578
The design of nanostructured biological architectures based on host–guest interactions between β-cyclodextrin and adamantane was investigated on SWCNT coatings using glucose oxidase (GOX) as biomolecule model. β-Cyclodextrin tagged GOX was immobilized on adamantane functionalized carbon nanotubes, deposited on platinum electrodes. Different functionalization techniques to attach “pyrene adamantane” on nanotubes were studied and compared in terms of the performances of the subsequently constructed glucose biosensors. The best results were obtained by dipping the nanotube deposit into a pyrene-adamantane solution followed by electropolymerization of the adsorbed pyrene monolayer. The constructed biosensor exhibited a good linear response toward glucose concentrations between 2 × 10−7 M and 1.6 × 10−3 M. The maximum current density and glucose sensitivity were 154.9 μA cm−2 and 14.4 mA M−1 cm−2, respectively. 相似文献
65.
This paper is a choral personal account on a longstanding and fruitful collaboration of organic and inorganic chemists to develop new hybrid polyoxometallic systems. .We explain our motivation and the context of our work that led to polyoxometalates with highly functional and reactive organic groups. Our approach yielded catalytically, biologically, and photochemically active systems. 相似文献
66.
Ayman ElAli Peter Thériault Serge Rivest 《International journal of molecular sciences》2014,15(4):6453-6474
Neurons are extremely vulnerable cells that tightly rely on the brain’s highly dynamic and complex vascular network that assures an accurate and adequate distribution of nutrients and oxygen. The neurovascular unit (NVU) couples neuronal activity to vascular function, controls brain homeostasis, and maintains an optimal brain microenvironment adequate for neuronal survival by adjusting blood-brain barrier (BBB) parameters based on brain needs. The NVU is a heterogeneous structure constituted by different cell types that includes pericytes. Pericytes are localized at the abluminal side of brain microvessels and contribute to NVU function. Pericytes play essential roles in the development and maturation of the neurovascular system during embryogenesis and stability during adulthood. Initially, pericytes were described as contractile cells involved in controlling neurovascular tone. However, recent reports have shown that pericytes dynamically respond to stress induced by injury upon brain diseases, by chemically and physically communicating with neighboring cells, by their immune properties and by their potential pluripotent nature within the neurovascular niche. As such, in this paper, we would like to review the role of pericytes in NVU remodeling, and their potential as targets for NVU repair strategies and consequently neuroprotection in two pathophysiologically distinct brain disorders: ischemic stroke and Alzheimer’s disease (AD). 相似文献
67.
Sai Hung CheungTodd A. Oliver Ernesto E. Prudencio Serge PrudhommeRobert D. Moser 《Reliability Engineering & System Safety》2011,96(9):1137-1149
In this paper, we apply Bayesian uncertainty quantification techniques to the processes of calibrating complex mathematical models and predicting quantities of interest (QoI's) with such models. These techniques also enable the systematic comparison of competing model classes. The processes of calibration and comparison constitute the building blocks of a larger validation process, the goal of which is to accept or reject a given mathematical model for the prediction of a particular QoI for a particular scenario. In this work, we take the first step in this process by applying the methodology to the analysis of the Spalart-Allmaras turbulence model in the context of incompressible, boundary layer flows. Three competing model classes based on the Spalart-Allmaras model are formulated, calibrated against experimental data, and used to issue a prediction with quantified uncertainty. The model classes are compared in terms of their posterior probabilities and their prediction of QoI's. The model posterior probability represents the relative plausibility of a model class given the data. Thus, it incorporates the model's ability to fit experimental observations. Alternatively, comparing models using the predicted QoI connects the process to the needs of decision makers that use the results of the model. We show that by using both the model plausibility and predicted QoI, one has the opportunity to reject some model classes after calibration, before subjecting the remaining classes to additional validation challenges. 相似文献
68.
Dunin-Barkowski Witali L. Shishkin Serge L. Wunsch Donald C. 《Neural Processing Letters》1999,9(2):97-106
In the last few decades it has been proven, that the cerebellum takes part in learning the bulk of motor control. The mechanisms which provide such properties are still largely unknown, but an involvement of parallel fibers and climbing fibers in this process, as have been proposed decades ago in cerebellar learning theories, is now clear. Among difficulties of the learning theories is an evident necessity for spontaneous activity of the cerebellar climbing fibers [5]. Recently, the group of M. Mauk proposed an elegant explanation of this inconsistency [11, 12]. We present here a stochastic model of a cerebellar module, based on this new approach. Theoretical treatment yields some consequences for experimental verification. Besides an explanation of real cerebellar functions, the analyzed control system presents a new paradigm for neural network memorizing systems. 相似文献
69.
This study was aimed at investigating which processes cause acidic herbicides (e.g., bentazone, MCPA and dichlorprop) to rapidly disappear in the lagoons of the Rhône delta, which are peculiar brackish and shallow aquatic environments. The use of the model MASAS (Modeling of Anthropogenic Substances in Aquatic Systems) revealed that sorption, sedimentation, volatilization, flushing and abiotic hydrolysis had a minor role in the attenuation of the investigated herbicides. Laboratory scale biodegradation and photodegradation studies were conducted to better assess the significance of these two processes in the natural attenuation of herbicides in brackish (lagoons) waters with respect to fresh waters (canals draining paddy fields). Herbicide biodegradation rates were significantly lower in lagoon water than in canal water. Consequently, photodegradation was the main dissipation route of all investigated herbicides. The contribution of indirect photolysis was relevant for MCPA and dichlorprop while direct photolysis dominated for bentazone removal. There is a need to further investigate the identity of phototransformation products of herbicides in lagoons. 相似文献
70.
Axel Schairer Serge Autexier Dieter Hutter 《Electronic Notes in Theoretical Computer Science》2001,58(2)
In interactive theorem proving, tactics and tacticals have been introduced to automate proof search. In this scenario, user interaction traditionally is restricted to the mode in which the user decides which tactic to apply on the top-level, without being able to interact with the tactic once it has begun running.We propose a technique to allow the implementation of derivational analogy in tactical theorem proving. Instead of replaying tactics including backtracked dead ends our framework makes choice points in tactics explicit and thus avoids dead ends when reusing tactics. Additionally users can override choices a tactic has made or add additional steps to a derivation without terminating the tactic. The technique depends on an efficient replay of tactic executions without repeating search that the original computation may have involved. 相似文献