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排序方式: 共有733条查询结果,搜索用时 31 毫秒
31.
Hai?HeEmail author Weiyi?Meng Clement?Yu Zonghuan?Wu 《The VLDB Journal The International Journal on Very Large Data Bases》2004,13(3):256-273
An increasing number of databases are becoming Web accessible through form-based search interfaces, and many of these sources are database-driven e-commerce sites. It is a daunting task for users to access numerous Web sites individually to get the desired information. Hence, providing a unified access to multiple e-commerce search engines selling similar products is of great importance in allowing users to search and compare products from multiple sites with ease. One key task for providing such a capability is to integrate the Web search interfaces of these e-commerce search engines so that user queries can be submitted against the integrated interface. Currently, integrating such search interfaces is carried out either manually or semiautomatically, which is inefficient and difficult to maintain. In this paper, we present WISE-Integrator - a tool that performs automatic integration of Web Interfaces of Search Engines. WISE-Integrator explores a rich set of special metainformation that exists in Web search interfaces and uses the information to identify matching attributes from different search interfaces for integration. It also resolves domain differences of matching attributes. In this paper, we also discuss how to automatically extract information from search interfaces that is needed by WISE-Integrator to perform automatic interface integration. Our experimental results, based on 143 real-world search interfaces in four different domains, indicate that WISE-Integrator can achieve high attribute matching accuracy and can produce high-quality integrated search interfaces without human interactions.Received: 2 January 2004, Accepted: 25 March 2004, Published online: 12 August 2004Edited by: M. Carey 相似文献
32.
The long-term (> 1000 years) hazards of high-level wastes (HLW) can be reduced substantially by practising waste-actinide partitioning-transmutation (P-T). This paper investigates the waste-actinide transmutation performance of a uranium hexafluoride actinide transmutation reactor (UHATR). Using mostly present-day and near-term technology, a preliminary UHATR design is established. Because of the gaseous nature of the fuel, very high neutron fluxes are obtained. Compared with an LWR, the average blanket thermal flux of this UHATR is about 10–30 times higher, leading to a 15-fold improvement in the percentage of actinides fissioned per year of irradiation. 相似文献
33.
A four-channel multiplexed electrospray interface on a triple quadrupole mass spectrometer was evaluated for the simultaneous validation of LC/MS/MS methods for the quantitation of loratadine and its metabolite, descarboethoxyloratadine, in four different biological matrixes. The assays were performed in rat, rabbit, mouse, and dog plasma from 1 to 1000 ng/mL using 96-well solid-phase extraction for sample preparation. The limit of quantitation of 1 ng/mL corresponded to 5.56 pg of each analyte injected on-column. For the drug, quality control samples (n = 6 at four concentrations) had precision ranging from 0.967 to 16.0% and accuracy ranging from -8.44 to 10.5% across all four species. For the metabolite, the precision ranged from 0.684 to 11.0% and the accuracy was between 6.36 and -9.06%. Intersprayer cross talk for the multiplexed electrospray ion source was evaluated as a function of analyte concentration and was less than 0.08% at concentrations as high as 1000 ng/mL. These results demonstrate the feasibility of using parallel analysis to reduce the time required for method validation and to increase sample throughput in drug development studies. 相似文献
34.
Many databases have become Web-accessible through form-based search interfaces (i.e., HTML forms) that allow users to specify
complex and precise queries to access the underlying databases. In general, such a Web search interface can be considered
as containing an interface schema with multiple attributes and rich semantic/meta-information; however, the schema is not
formally defined in HTML. Many Web applications, such as Web database integration and deep Web crawling, require the construction
of the schemas. In this paper, we first propose a schema model for representing complex search interfaces, and then present
a layout-expression based approach to automatically extract the logical attributes from search interfaces. We also rephrase
the identification of different types of semantic information as a classification problem, and design several Bayesian classifiers
to help derive semantic information from extracted attributes. A system, WISE-iExtractor, has been implemented to automatically
construct the schema from any Web search interfaces. Our experimental results on real search interfaces indicate that this
system is highly effective. 相似文献
35.
Luke M. Geever César M. Mínguez Declan M. Devine Michael J. D. Nugent James E. Kennedy John G. Lyons Austin Hanley Sinead Devery Paul T. Tomkins Clement L. Higginbotham 《Journal of Materials Science》2007,42(12):4136-4148
In this contribution thermosensitive polymer matrices based on N-isopropylacrylamide have been developed. The hydrogels were prepared by photopolymerisation of N-isopropylacrylamide and 1-vinyl-2-pyrrolidinone in appropriate amounts of distilled water. The monomers were cured using
a UV-light sensitive initiator called 1-hydroxycyclohexylphenylketone. These copolymers were crosslinked using ethylene glycol
dimethacrylate and poly(ethylene glycol) dimethacrylate with molecular weights 600 and 1,000, at 0.1 wt% of the total monomer
content. The chemical structure of the xerogels was characterised by means of Fourier transform infrared spectroscopy (FTIR)
and the transition temperature of the hydrogels was determined using modulated differential scanning calorimetry (MDSC). By
altering the feed ratio, hydrogels were synthesised to have lower critical solution temperatures (LCST) around 37 °C. This
ability to shift the phase transition temperature of the gels provides excellent flexibility in tailoring transitions for
specific uses. The samples synthesised with PEG1000DMA crosslinking agents absorbed over 18 times their weight in water, while
maintaining good gel integrity thus falling marginally short of being characterised as superabsorbent. Each of the samples
showed similar deswelling behaviour at 37 °C. Rheological studies showed that increasing the molecular weight of the crosslinking
agent caused an increase in hydrogel strength. 相似文献
36.
37.
An effective model for predicting multicomponent aerosol evaporation in the upper respiratory system that is capable of estimating the vaporization of individual components is needed for accurate dosimetry and toxicology analyses. In this study, the performance of evaporation models for multicomponent droplets over a range of volatilities is evaluated based on comparisons to available experimental results for conditions similar to aerosols in the upper respiratory tract. Models considered include a semiempirical correlation approach as well as resolved-volume computational simulations of single and multicomponent aerosol evaporations to test the effects of variable gas-phase properties, surface blowing velocity, and internal droplet temperature gradients. Of the parameters assessed, concentration-dependent gas-phase specific heat had the largest effect on evaporation and should be taken into consideration for respiratory aerosols that contain high volatility species, such as n-heptane, at significant concentrations. For heavier droplet components or conditions below body temperatures, semiempirical estimates were shown to be appropriate for respiratory aerosol conditions. In order to reduce the number of equations and properties required for complex mixtures, a resolved-volume evaporation model was used to identify a twelve-component surrogate representation of potentially toxic JP-8 fuel based on comparisons to experimentally reported droplet evaporation data. Due to the relatively slow evaporation rate of JP-8 aerosols, results indicate that a semiempirical evaporation model in conjunction with the identified surrogate mixture provide a computationally efficient method for computing droplet evaporation that can track individual toxic markers. However, semiempirical methodologies are in need of further development to effectively compute the evaporation of other higher volatility aerosols for which variable gas-phase specific heat does play a significant role. 相似文献
38.
Markku Kulmala Üllar Rannik Evgeni L. Zapadinsky Charles F. Clement 《Journal of aerosol science》1997,28(8):1395-1409
In the atmosphere the saturation ratio of water vapour varies as a function of time and space. In the present study we have investigated the effects of fluctuations of saturation ratio on droplet (cloud condansation nuclei) growth by stochastic approach employing an advanced growth model for cloud droplets. In saturated mean conditions growth of cloud droplets is accelerated by the fluctuations of saturation ratio, and our results indicate that due to fluctuations some droplets are able to grow in undersaturated conditions. Stochastic fluctuations of saturation ratio result in appearance of bimodal particle-size distribution and this is one of the possible explanations for the observed two modal cloud droplet distribution. 相似文献
39.
Max Müller W. Sutthoff M. Pleißner J. Clement und G. Sonntag 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1911,21(2):109-114
Ohne Zusammenfassung 相似文献
40.
A. Scholl C. A. Neufeld G. Sonntag und J. Clement 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1910,19(9):503-510
Ohne Zusammenfassung 相似文献