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961.
Di Iorio E Barbaro V Ferrari S Ortolani C De Luca M Pellegrini G 《Microscopy research and technique》2006,69(12):983-991
Fluorescence microscopy has long been used for qualitative characterization of various parameters such as subcellular distribution of proteins, lipids, nucleic acids, and ions. However, quantification of these parameters is complicated by a variety of optical, biological, and physical factors. In the last decade, the progress achieved with powerful softwares and digital image processing systems has facilitated the development of fluorescence immunohistochemistry (FIHC) into a widely used quantitative assay (quantitative-FIHC or Q-FIHC). We describe here a rapid and sensitive Q-FIHC assay based on the use of a laser scanning confocal microscope and advanced image analysis softwares (Zeiss semi automatic LSM 510 and fully automatic Axiovision 4.4) for the detection and quantification of fluorescent intensity in human corneal tissues and cells obtained from small clinical samples. We have used this methodology to characterize and quantify the gene expression profile of p63 and its DeltaNalpha isoform, specific markers of human limbal stem cells. The validity of this method was evaluated through comparative studies with conventional approaches suggesting no significant differences and providing an alternative technique to traditional methods. Since Q-FIHC requires at least 20-fold less cells than traditional techniques, we have adopted it as the main quality control for our limbal cultures destined to clinical application. 相似文献
962.
Fernanda M. B. Coutinho Luciene F. Monteiro Marcos A. S. Costa Luiz Claudio Santa Maria Sônia M. C. Menezes 《Polymer Bulletin》1998,40(4-5):423-429
The present work deals with copolymerization of styrene (STY) and methyl methacrylate (MMA) catalysed by nickel acetylacetonate
- Ni(acac)
2
, employing methylaluminoxane (MAO) as cocatalyst. This catalyst system presented low catalyst activities for STY homopolymerization
and very high activities for MMA. It seems that the catalyst system based on Ni(acac)
2
/MAO is effective for the copolymerization of MMA and STY to give block copolymer but it also produced polystyrene and poly(methyl
methacrylate) homopolymers. The polymers were characterized by
13
C NMR, GPC and FTIR. The polystyrene homopolymer was identified by IR and NMR analyses of the cyclohexane soluble fraction.
The presence of absorption bands correspondent to carbonyl group and aromatic ring was observed in the IR spectrum of the
acetic acid soluble part. This result is a clue that STY-MMA copolymer with low molecular weight was produced. The high molecular
weight copolymer (acetic acid insoluble fraction) was also characterized by IR analysis which indicated the presence of characteristic
absorption bands of carbonyl group and aromatic ring. These results were confirmed by
13
C NMR analysis.
Received: 6 August 1997/Revised version: 29 December 1997/Accepted: 7 January 1998 相似文献
963.
A new approach to natural gas flow computer design is presented in this paper. The developed system runs on a personal computer and employs the state-of-the-art mathematical models for corrections of some aspects of fluid flow dynamics, as well as for compressible behavior of gaseous fluid considerations. Orifice plates were used as primary elements. Measurements were performed through intelligent sensors. Results of the system metrological tests are also presented. 相似文献
964.
Claudio L. A. Berli 《Microfluidics and nanofluidics》2008,4(5):391-399
Equivalent circuit modeling of microfluidic chips accounts for the transport of fluid and electricity in the entire network
of microchannels as a function of the applied pressure and electric potentials. For these calculations, each microchannel
is represented by a set of conductance coefficients that relates to driving forces and conjugate flows. Theoretical expressions
of the coefficients for rectangular microchannels with arbitrary values of the cross-sectional aspect ratio are derived from
the fundamentals of electrokinetic phenomena. Particular emphasis is placed on the analysis of the conditions under which
the equivalent circuit model can be accurately employed. Model predictions successfully match data on electrokinetically driven
chips for immunoassays reported in the literature. A simulation example is also given to illustrate the capability of the
technique for the design and manipulation of analytical microsystems. 相似文献
965.
Claudio Fabio Claudio Davide Tapani Juha Fabio Jari 《Journal of Systems Architecture》2008,54(12):1143-1154
This paper describes an open-source and highly scalable floating-point unit (FPU) for embedded systems. Our FPU is fast and efficient, due to the high parallelism of its architecture: the functional units inside the datapath can operate in parallel and independently from each other. A comparison between different versions of the FPU has been made to highlight how performance scales accordingly. Logic synthesis results show that our FPU requires 105 Kgates and runs at 400 MHz on a low-power 90 nm std-cells low-power technology, and requires 20 K Logic Elements running at 67 MHz of an Altera Stratix FPGA. The proposed FPU is supported by a software tool suite which compiles programs written using the C/C++ language. A set of DSP and 3D graphics algorithms have been benchmarked, showing that using our FPU the amount of clock cycles required to perform each algorithm is one order of magnitude smaller than what is required by its corresponding software implementation. 相似文献
966.
Arash Azarfar Claudio S Ferreira Jacob O Goelema Antonius FB Van der Poel 《Journal of the science of food and agriculture》2008,88(8):1380-1384
BACKGROUND: Rapeseed is a protein supplement that contains up to 40% crude protein (CP) on a dry matter (DM) basis, but a large part of its protein can be easily degraded in the rumen. Therefore, before inclusion in ruminant's diet, the extent of its protein degradation in the rumen must be reduced without altering its intestinal digestibility. A study was conducted to investigate the effects of pressure toasting (T, 130 °C) at two residence times (1.5 and 10 min) alone or in combination with soaking in water (ST, 4 h) on ruminal degradability and intestinal digestibility of CP and protein‐free organic matter (PFOM) in whole full‐fat rapeseed. RESULTS: Regardless of the processing time (1.5 or 10 min), T significantly (P < 0.05) increased the fraction of undegraded intake protein (UIP) compared to the untreated rapeseed samples. Soaking prior to further toasting did not improve the rumen degradation characteristics of rapeseed CP. Compared to the untreated rapeseed samples, both T and ST significantly (P < 0.0001) improved the true protein digested in the small intestine (DVE) and degraded protein balance (OEB), effects that were more evident in samples heated for 10 min. Soaking prior to pressure toasting, however, did not further improve the DVE or OEB in the rapeseed samples in comparison with T treatment. CONCLUSIONS: It was concluded that ruminal protein degradability of rapeseed decreased after pressure toasting, without seriously affecting its intestinal digestibility. Copyright © 2008 Society of Chemical Industry 相似文献
967.
Claudio J. Pérez 《Polymer》2005,46(3):725-732
Well-characterized linear ethylene-butene-1 copolymers with polydispersities lower than 1.1 were modified using an organic peroxide with the purpose of assessing the relative importance of chain-linking processes. The copolymers used in this work were obtained by hydrogenation of polybutadienes, which were synthesized by anionic polymerization of butadiene. All the copolymers were modified in the molten state using 2,5-dimethyl-2,5 di(terbutyl peroxy)-hexane with concentrations varying on a ample range. The changes in the molecular structure of the polymers due to the chemical attack of the peroxide were evaluated combining selective solvent extraction and GPC-MALLS techniques. As expected, the critical concentration required for the onset of gelation, Cc, decreases with average molecular mass of the original copolymer. When concentrations of peroxide below Cc are employed, the weight-average molecular mass of the modified copolymers augments and the molecular mass distribution gets wider as the concentration of peroxide added to the copolymer increases. Although, the chain-linking reactions govern the modification process, there is a fraction of molecular chains that suffers scission. The measurable fraction of molecules having molecular mass lower than the original quasi-monodisperse copolymers ranges between 15% and 24% of the total mass when the copolymers were modified with concentrations of peroxide below Cc. Beyond the onset of gelation, the gel amount increases continuously with the peroxide concentration added to the copolymers. At a given peroxide concentration, the amount of gel produced for a given polymer is higher the greater is the initial molecular mass of the modified polymer. The limiting amount of gel was between 90% and 98% of the total mass, which was reached using concentrations 20 times larger than the critical one. The efficiency of the peroxide as cross-linking agent seems to be dependent on the concentration of peroxide. 相似文献
968.
969.
Masahiro Shirato Roberto Paolucci Tetsuya Kouno Shoichi Nakatani Jiro Fukui Roberto Nova Claudio di Prisco 《Soils and Foundations》2008,48(5):693-711
A dynamic analysis model for the nonlinear behavior of a shallow foundation subjected to seismic loads is developed. A macro-element approach is revised assuming elasto-uplift-plastic behavior, in which uplifting and coupling effects of vertical, horizontal, and moment loads are taken into account. Large-scale shake table experiments of model pier footings are also conducted and simulated using the revised macro-element model. The numerical result reveals that the shape of the hysteresis loops for coupled load-displacement relationships is predicted very well, including the effects of uplift. In addition, the revised model can account for settlement with some inclination that has accumulated during the excitation. 相似文献
970.
We introduce a new class of dynamic encoders for continuous-time nonlinear control systems which update their parameters only at discrete times. We prove that the information reconstructed from the encoded feedback can be used to deliver a piece-wise constant control law which yields semi-global practical stability. 相似文献