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A cross-sectional study was performed in eight companies, comprising 32 buildings without previously recognized indoor air problems. Engineers filled in a technical questionnaire on building characteristics, floor surface materials, ventilation, cleaning procedures, heating and cooling. A total of 3562 employees returned questionnaires on individual factors, workload, perceived physical work environment, allergy and symptoms. Frequent symptoms were feeling of fatigue or heavy-headedness, eye irritation, and dry facial skin. Women reported symptoms more frequently than men. Employees with allergy had a 1.8-2.5 times risk of reporting a high score for general, skin, or mucosal symptoms. The risk of a high symptom score increased with daily visual display unit (VDU) work time. Passive smoking and psychosocial load were also relatively strong predictors of symptoms. Weekly cleaning as compared with a frequency of cleaning two to four times a week increased the risk of symptoms. Adjusted odds ratio for a high general symptoms score from infrequent cleaning was 1.5 (95%CI 1.1-2.0). A high ventilation flow or central ventilation unit filter EU7 vs. EU8 seemed to be associated with an increased risk of general symptoms. Absence of local temperature control increased the risk of mucosal symptoms. 相似文献
83.
Markus Levy Shay GAL-ON 《今日电子》2007,(4):50-51
随着嵌入式系统在消费电子和工业设备中的广泛应用,功耗已经开始像时钟速度和系统性能一样成为微处理器的一个核心特性.为了确定各种微处理器的功耗效率,嵌入式微处理器基准协会开发了一个有力的工具--EnergyBench. 相似文献
84.
Defect propagation at a circular interface 总被引:1,自引:0,他引:1
In this paper a nonlinear, nonuniform cohesive zone is employed to study the detailed features of quasi-static defect evolution
in a simple, planar elastic system consisting of a circular inclusion embedded in an unbounded matrix subject to different
remote loading configurations. The inclusion–matrix interface is assumed to be described by Needleman-type force-separation
relations characterized by an interface strength, a characteristic force length and a shear stiffness parameter. Interface
defects are modeled by an interface strength which varies with interface coordinate. Infinitesimal strain equilibrium solutions,
which allow for rigid body inclusion displacement, are sought by eigenfunction approximation of the solution of the governing
interfacial integral equations. For equibiaxial tension, quasi-static defect initiation and propagation occur under increasing
remote load. For decreasing characteristic force length, a transition occurs from more or less uniform decohesion along the
bond line to propagation of a crack-like defect. In the later case a critical failure load is well defined and interface failure
is shown to be defect dominated (brittle decohesion). For interfaces with large characteristic force length, the matrix “lifts
off” the inclusion accompanied by a delay in defect propagation (ductile decohesion). The decohesion modes ultimately give
rise to a cavity with the inclusion situated within it on the side opposite to the original defect. Results for small characteristic
force length show consistency with England’s results for the sharp arc crack on a circular interface (England AH (1966) ASME
J Appl Mech 33:637–640) Stress oscillation and contact at the tip of the defect are observed primarily for small characteristic
force lengths under extremely small loading. Results for remote tension, compression and pure shear loading are discussed
as well. In the final section of the paper the results obtained in the first part are utilized to estimate the plane effective
bulk response of a composite containing a dilute distribution of inclusions with randomly oriented interface defects. 相似文献
85.
Aaron Gidding Yuma Matsui Thomas E. Levy Tom DeFanti Falko Kuester 《Future Generation Computer Systems》2013,29(8):2117-2127
The broad adoption of diagnostic and analytical techniques in the field of archeology, presents a unique opportunity for e-Science in the form of scientific explanation, drawing from methodologies aimed at recording, archiving, analyzing, and disseminating, rich data collections to create the needed infrastructure for both research and web-based curation and data management system. This paper presents a needed stepping stone towards synergy between information technology and archeology, by introducing a data acquisition, tagging and characterization pipeline along with a novel method for spatially querying archeological data. 相似文献
86.
Madathiparambil Ranganathapai Ramesh kumar Abhay Devasthale Gad Levy Syam Sankar Stephan Bakan Hartmut Grassl 《International journal of remote sensing》2013,34(9):2925-2936
We characterize the climatological features of the double inter-tropical convergence zones (DITCZs) over the western Indian Ocean during November–December by a synergistic analysis of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS III) data (1988–2005) and the National Aeronautics and Space Administration's (NASA's) A-Train data (2002–2009). We investigate rainfall, freshwater flux and cloud liquid water, cloud fraction and relative humidity over the DITCZs. In addition, the daily rainfall data from the Global Precipitation Climatology Project (GPCP) are used to document the DITCZs during the El Niño southern oscillation (ENSO) events. An analysis of the GPCP data shows that the DITCZs are clearly discernible during strong ENSO events (1997, 2002 and 2006), in sharp contrast to the DITCZs in the eastern Pacific Ocean, where they are absent during ENSOs. Further, these convergence zones on either side of the equator are of short duration, approximately 3–6 pentads during November and December. All satellite sensor data sets consistently capture the major features of DITCZs. As an accurate simulation of DITCZs in coupled global climate models remains a challenge, the results from the present study would provide a platform for evaluating these models. 相似文献
87.
Mobile user tracking is a major issue. We propose a novel approach for user tracking, in which the tracking activity is adapted to both user and system activity. The basic idea is to make the user-location update-rate dependent not only on the user activity (such as the call profile and mobility pattern). Rather, it is also made dependent on the signaling load, which reflects the actual cost of the update operation. Thus, at low-signaling load locations, the users are to transmit location update messages more frequently. To carry out this approach, we propose a load-adaptive threshold scheme (LATS): the network determines for each cell a registration threshold level (which depends on the cell load) and announces it, as a broadcast message, to the users. The user computes its own registration priority and then transmits a registration message only if its priority exceeds the announced threshold level. Thus, whenever the local load on the cell is low, the registration activity increases, while in loaded cells the registration activity decreases. Our analysis shows that the LATS reduces the paging cost, in comparison with other dynamic methods, without increasing the wireless cost of registration. Moreover, if higher user density is coupled with less mobility (e.g., consider vehicles), then the LATS strategy offers further performance improvement. The load-adaptive strategy can be used in addition to any other dynamic tracking strategy. Furthermore, the computational complexity imposed on the user is identical to that required by an equivalent load-insensitive scheme 相似文献
88.
Ronald M. Levy 《Israel journal of chemistry》1986,27(2):173-179
The use of molecular dynamics simulations to study the internal motions and structural flexibility of proteins and nucleic acids has received a great deal of attention in recent years. The attraction of the method is, in part, its potential for studying detailed properties of biological macromolecules that are only indirectly accessible to experiment. Equally important is the use of the method to provide a more fundamental understanding of the molecular information contained in various kinds of experiments on these complex systems. In this paper we review recent work in our laboratory concerned with the use of computer simulations for the interpretation of experimental probes of molecular structure and dynamics of proteins and nucleic acids. The interplay between computer simulations and three experimental techniques are emphasized: (1) nuclear magnetic resonance relaxation spectroscopy; (2) refinement of macromolecular X-ray structures; and (3) vibrational spectroscopy. 相似文献
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