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81.
Vladik?KreinovichEmail author Luc?Longpré Praveen?Patangay Scott?Ferson Lev?Ginzburg 《Reliable Computing》2005,11(1):59-76
In many application areas,it is important to detect outliers. The traditional engineering approach to outlier detection is that we start with some normal values x1, ...,xn, compute the sample average E, the sample standard variation , and then mark a value x as an outlier if x is outside the k0-sigma interval [E – k0 , E + k0 ] (for some pre-selected parameter k0).In real life,we often have only interval ranges [
] for the normal values x1, ...,xn. In this case,we only have intervals of possible values for the bounds
and
. We can therefore identify outliers as values that are outside all k0-sigma intervals.Once we identify a value as an outlier for a fixed k0, it is also desirable to find out to what degree this value is an outlier, i.e., what is the largest value k0 for which this value is an outlier.In this paper,we analyze the computational complexity of these outlier detection problems, provide efficient algorithms that solve some of these problems (under reasonable conditions), and list related open problems. 相似文献
82.
Lev Manovich 《AI & Society》2000,14(2):176-183
After the novel, and subsequently cinema privileged narrative as the key form of cultural expression of the modern age, the computer age introduces its correlate — database. Why does new media favour database form over others? Can we explain ist popularity by analysing the specificity of the digital medium and of computer programming? What is the relationship between database and another form, which has traditionally dominated human culture — narrative? In addressing these questions, I discuss the connection between computer's ontology — the way software represents the world — and the new cultural forms privileged by computer culture such as database. I propose that computerisation of culture involves projection of two fundamental parts of computer software — data structures and algorithms — onto the cultural sphere. Thus CD-ROMs and Web databases are cultural manifestations of one half of this ontology — data structures; while new media narratives are manifestations of the second part — algorithms. I conclude by proposing that in computer culture database and narrative do not have the same status. Given that on the level of data organisation most new media objects are databases, it is not surprising that on the level of form database also dominates new media culture. 相似文献
83.
The concept of Quality of Service (QoS) networks has gained
growing attention recently, as the traffic volume in the Internet
constantly increases, and QoS guarantees are essential to ensure
proper operation of most communication-based applications. A QoS
switch serves m incoming queues by transmitting packets arriving
to these queues through one output port, one packet per time step.
Each packet is marked with a value indicating its priority in the
network. Since the queues have bounded capacities and the rate of
arriving packets can be much higher than the transmission rate,
packets can be lost due to insufficient queue space. The goal is
to maximize the total value of transmitted packets. This problem
encapsulates two dependent questions: buffer management, namely
which packets to admit into the queues, and scheduling, i.e. which
queue to use for transmission in each time step. We use
competitive analysis to study online switch performance in QoS-based networks. Specifically, we provide a novel generic technique
that decouples the buffer management and scheduling problems. Our
technique transforms any single-queue buffer management policy
(preemptive or non-preemptive) to a scheduling and buffer
management algorithm for our general m queues model, whose
competitive ratio is at most twice the competitive ratio of the
given buffer management policy. We use our technique to derive
concrete algorithms for the general preemptive and non-preemptive
cases, as well as for the interesting special cases of the 2-value
model and the unit-value model. We also provide a
1.58-competitive randomized algorithm for the unit-value case.
This case is interesting by itself since most current networks
(e.g. IP networks) do not yet incorporate full QoS capabilities, and
treat all packets equally. 相似文献
84.
Zvi Mendel Lev Zegelman Alfred Hassner Fabienne Assael Miriam Harel Shlomo Tam Ezra Dunkelblum 《Journal of chemical ecology》1995,21(3):331-341
The active component of the sex pheromone ofMatsucoccus josephi is (2E,6E,8E)-5,7-dimethyl-2,6,8-decatrien-4-one; the chemical is also a powerful kairomone of adult males and females of the bugElatophilus hebraicus the principal predator ofM. josephi. The presence of theZ isomer (2E,6Z,8E)-5,7-dimethyl-2,6,8-decatrien-4-one does not interfere with the attractancy of the activeE component forM. josephi males or the bug. Our results show a clear dose-response between trap catch ofM. josephi males andE. hebraicus. Conversely, increasing amounts of theZ isomer in the mixture did not affect the attraction of the scale insect males or the bug. The catch ofM. josephi males did not differ significantly among traps of different color, and was significantly higher with traps attached to the tree trunk than those suspended between trees. Comparison of the catch ofM. josephi among the three forests and between pine species suggests that the level of infestation ofPinus halepepsis andPinus brutia ssp.brutia is similar, despite the fact that the latter pine is resistant to the scale insect. Both sexes ofE. hebraicus were trapped in much lower numbers at the more infested sites. This may be related to interference with the activity ofE. hebraicus due to deterioration and drying of parts of the tree crowns and heavy colonization by generalist predators in injured trees. 相似文献
85.
A Roadmap for Controlled and Efficient n‐Type Doping of Self‐Assisted GaAs Nanowires Grown by Molecular Beam Epitaxy 下载免费PDF全文
Marta Orrù Eva Repiso Stefania Carapezzi Alex Henning Stefano Roddaro Alfonso Franciosi Yossi Rosenwaks Anna Cavallini Faustino Martelli Silvia Rubini 《Advanced functional materials》2016,26(17):2836-2845
N‐type doping of GaAs nanowires has proven to be difficult because the amphoteric character of silicon impurities is enhanced by the nanowire growth mechanism and growth conditions. The controllable growth of n‐type GaAs nanowires with carrier density as high as 1020 electron cm?3 by self‐assisted molecular beam epitaxy using Te donors is demonstrated here. Carrier density and electron mobility of highly doped nanowires are extracted through a combination of transport measurement and Kelvin probe force microscopy analysis in single‐wire field‐effect devices. Low‐temperature photoluminescence is used to characterize the Te‐doped nanowires over several orders of magnitude of the impurity concentration. The combined use of those techniques allows the precise definition of the growth conditions required for effective Te incorporation. 相似文献
86.
Victor Stepanov Venant Anglade Wendy A. BalasHummers Andrey V. Bezmelnitsyn Lev N. Krasnoperov 《Propellants, Explosives, Pyrotechnics》2011,36(3):240-246
The initiation sensitivity of cyclotrimethylenetrinitramine (RDX) was investigated as a function of crystal size. For this study, RDX powders with mean crystal sizes of ca. 200 and 500 nm were prepared by rapid expansion of supercritical solutions (RESS) with carbon dioxide as the solvent. Initiation sensitivity testing to impact, sustained shock, and electrostatic discharge stimuli was performed on uncoated as well as wax‐coated specimens. The test data revealed that in a direct comparison to coarser grades the nanocrystalline RDX‐based samples were substantially less sensitive to shock and impact stimuli. Furthermore, the 500 nm RDX‐based specimens exhibited the lowest sensitivity values, an indication that minima in shock and impact sensitivities with respect to crystal size exist. 相似文献
87.
The paper is devoted to comparison of electroslag remelting (ESR) with consumable electrode and electroslag refining with liquid metal (ESR LM) processes. The possibility of rearrangement of the heat contributions coming from the consumable electrode and current supplying mould (non-consumable electrode, CSM) makes the core of the ESR process organisation in the CSM. The usage of liquid metal instead of consumable electrodes allows to reduce liquid bath temperature and volume in order to provide low segregation ingot. The formal assessment of physico-chemical conditions and experimental measurements of desulphurisation have shown the same level of refining ability of both processes. Replacing the classic ESR by the ESR LM is a prospective way to produce high-quality ingots from sophisticated and hard-to-deform materials, whereas manufacturing of the consumable electrodes is technically problematic and costly. 相似文献
88.
89.
Artem A.Eliseev Lev A.Trusov Evgeny O.Anokhin Andrei P.Chumakov Vladimir V.Korolev Anastasia E.Sleptsova Peter Boesecke Vladimir Ya.Shur Vladimir YaShur Pavel E.Kazin Andrei A.Eliseev 《Nano Research》2022,(2):898-906
Structural ordering in the concentrated magnetic colloids containing 50×5 nm hard magnetic disc-like SrFe12O19 nanoparticles was investigated by cryogenic scanning electron microscopy,optical microscopy,magnetic measurements,and small-angle X-ray scattering.It was revealed that macroscopically homogeneous magnetic liquid consists of dynamic threads of stacked nanoparticles.The threads align into quasiperiodic arrays with the distances between individual threads of a few micrometers.They also can form pseudodomain structures with -90°domain boundaries realized through T-type thread interconnects.The effects of magnetic attraction and electrostatic repulsion on the equilibrium interplatelet distance in the threads were studied.It was demonstrated that this distance can be tuned by the control of the particles charge and electric double layer screening from Stern layer thickness(-1 nm)to tens of nanometers.It was shown that the permanent magnetic field is not able to cause any structural changes in the ordered magnetic liquid phase,while alternating field draws particles apart by their vibrations.External variation of interparticle distance up to 6%was achieved using an alternating magnetic field of low intensity.Experimental data were complemented by the theoretical models of screened electrostatic interactions between spherical and platelike magnetic particles.The last model provides good predictive power and correlates with the experimental data.The stabilization energy of the condensed phase in the order of 1-10 kBT was derived from the model.An approach allows controlling of an equilibrium interparticle distance and interparticle distance distribution by adjusting the magnetization and surface charge of the particles as well as the ionic strength of the solvent. 相似文献
90.
Joseph Appelbaum Nathan Croitoru Lev Klibanov David Scheinman 《Progress in Photovoltaics: Research and Applications》2000,8(6):571-578
The unique properties of the diamond‐like carbon (a:DLC), such as high mechanical hardness and abrasive resistance, optical transparency in the visible and IR spectral regions and high thermal conductivity, provide this material with advantages over other types of protecting materials for solar cells. Furthermore, the a:DLC films are inert to corrosive gases and other corrosive agents. Resistance to radiation damage of the a:DLC films deposited on solar cells is very important for space application. In the study we investigate the effect of electron damage on silicon solar cells coated with a:DLC films. We measure the I – V characteristic and the spectral response and calculate the values of the seven parameters of the double exponential solar cell model (usually not investigated) as a function of electron fluence irradiation. In addition we obtain also the usual external parameters Isc, Voc, Im, Vm, FF, and efficiency) of the solar cells. We investigate solar cells with and without anti‐reflecting coating coated with a:DLC films which were exposed to electron radiation. The main findings show that the solar cells with a:DLC films of thickness up to 500 nm degrade similarly to regular silicon cells exposed to electron irradiation. The degradation of the spectral response of the solar cell is mainly in the range of longer wavelengths and the irradiation affects the solar cell parameters (mainly the reverse saturation currents). Copyright © 2000 John Wiley & Sons, Ltd. 相似文献