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51.
Since its introduction in 2000, there has been much interest in the use of optical mouse technology for displacement sensing and motion tracking. A conventional optical mouse configuration uses a single source of illumination but tests have shown that this can result in differences in sensor sensitivity in the x- and y-axes. This paper presents an investigation into the use of an optical mouse sensor for a two-dimensional, contact-free measurement device. It has been found that two-axis illumination can improve the accuracy of position measurement in two dimensions when compared with single-axis illumination. The effects of acceleration and deceleration on sensor accuracy have also been considered and it has been shown that sensor sensitivity is higher under conditions of acceleration than when decelerating. 相似文献
52.
Tomasz Fałat Kazimierz Friedel Norman Marenco Stephan Warnat 《Microsystem Technologies》2009,15(1):181-190
The current paper focuses on several mechanical aspects of a waferlevel packaging approach using a direct face-to-face Chip-to-Wafer
(C2W) bonding of a MEMS device on an ASIC substrate wafer. Requirements of minimized inherent stress from packaging and good
decoupling from forces applied in manufacturing and application are discussed with particular attention to the presence of
through-silicon vias (TSV) in the substrate wafer. The paper deals with FEM analysis of temperature excursion, pressure during
molding, materials used and handling load influence on mechanical stress within the TSV system and on wafer level, which can
be large enough to disintegrate the system. 相似文献
53.
Anthony?Etuk Timothy?J.?Norman Murat??ensoyEmail author Mudhakar?Srivatsa 《Autonomous Agents and Multi-Agent Systems》2017,31(3):531-560
The presence of numerous and disparate information sources available to support decision-making calls for efficient methods of harnessing their potential. Information sources may be unreliable, and misleading reports can affect decisions. Existing trust and reputation mechanisms typically rely on reports from as many sources as possible to mitigate the influence of misleading reports on decisions. In the real world, however, it is often the case that querying information sources can be costly in terms of energy, bandwidth, delay overheads, and other constraints. We present a model of source selection and fusion in resource-constrained environments, where there is uncertainty regarding the trustworthiness of sources. We exploit diversity among sources to stratify them into homogeneous subgroups to both minimise redundant sampling and mitigate the effect of certain biases. Through controlled experiments, we demonstrate that a diversity-based approach is robust to biases introduced due to dependencies among source reports, performs significantly better than existing approaches when sampling budget is limited and equally as good with an unlimited budget. 相似文献
54.
Karel Domansky Josiah D. Sliz Norman Wen Christopher Hinojosa Guy ThompsonII Jacob P. Fraser Tiama Hamkins-Indik Geraldine A. Hamilton Daniel Levner Donald E. Ingber 《Microfluidics and nanofluidics》2017,21(6):107
The majority of microfluidic devices used for cell culture, including Organ-on-a-Chips (Organ Chips), are fabricated using polydimethylsiloxane (PDMS) polymer because it is flexible, optically clear, and easy to mold. However, PDMS possesses significant challenges for high volume manufacturing and its tendency to absorb small hydrophobic compounds limits its usefulness as a material in devices used for drug evaluation studies. Here, we demonstrate that a subset of optically clear, elastomeric, styrenic block copolymers based on styrene-ethylene-butylene-styrene exhibit reduced absorption of small hydrophobic molecules and drug compounds compared to PDMS and that they can be fabricated into microfluidic devices with fine features and the flexibility required for Organ Chips using mass production techniques of injection molding and extrusion. 相似文献
55.
Aging and imperfections provide important visual cues for realism. We present a novel physically‐based approach for simulating the biological aging and decay process in fruits. This method simulates interactions between multiple processes. Our biologically‐derived, reaction‐diffusion model generates growth patterns for areas of fungal and bacterial infection. Fungal colony spread and propagation is affected by both bacterial growth and nutrient depletion. This process changes the physical properties of the surface of the fruit as well as its internal volume substrate. The fruit is physically simulated with parameters such as skin thickness and porosity, water content, flesh rigidity, ambient temperature, humidity, and proximity to other surfaces. Our model produces a simulation that closely mirrors the progression of decay in real fruits under similar parameterized conditions. Additionally, we provide a tool that allows artists to customize the input of the program to produce generalized fruit simulations. 相似文献
56.
On the elastic modulus degradation in continuum damage mechanics 总被引:6,自引:0,他引:6
To measure accurately the elastic modulus of a metal, E, can be a difficult task when a specimen undergoes plastic strains. Moreover, some failure criteria, such as those associated with Continuum Damage Mechanics, require the change of elastic modulus with strain to define a measure of damage, D, in a material or structure. Thus, it is important to assess the possible geometrical influence of a specimen on the measurement of the elastic modulus at different deformation levels. It is shown in this article, with the aid of a numerical simulation, that any plastic strains induce important geometrical effects in the evaluation of E, which have a significant influence on the evaluation of the scalar damage parameter, D. 相似文献
57.
Jim Spohrer Laura C. Anderson Norman J. Pass Tryg Ager Daniel Gruhl 《Journal of Grid Computing》2008,6(3):313-324
This paper is a first exploration of the relationship between service science and Grid computing. Service science is the study
of value co-creation interactions among entities, known as service systems. Within the emerging service science community,
service is often defined as the application of competences (resources) for the benefit of another. Grid computing is the study
of resource sharing among entities, known as virtual organizations, which solve complex business, societal, scientific, and
engineering problems. Within the Grid computing community, service is sometimes defined as protocols plus behavior. Both Grid
computing and service science are connecting academic, industry, government, and volunteer sector collaborators on a range
of projects including eScience, healthcare, environmental sustainability, and more. This paper compares and contrasts the
notions of resource, entity, service, interaction, and success criteria for the two areas of study. In conclusion, new areas
for collaborative inquiry are proposed. 相似文献
58.
59.
LeCronier DJ Papakonstantinou JS Gheevarughese V Beran CD Walter NE Atkinson PJ 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2012,226(4):330-336
Previous animal models have been developed to study intramedullary nailing for challenging segmental defects in the tibia. In large animals, interlocked nail fixation created a stable environment suitable to study new bone growth technologies placed in the defect. To our knowledge, there are no comparable interlocked tibial defect models for the rabbit in which new technologies could be evaluated. Such a model would be helpful since the rabbit is a popular initial model for orthopedic research studies owing to its wide availability and low cost. While numerous studies have nailed the rabbit tibia, all were non-locked implants that allowed some degree of instability between the fracture fragments. In addition, the non-locked nails were constructed of stainless steel, whereas human nails are increasingly made from titanium alloy. In the current study, an interlocked titanium nail was developed for the rabbit tibia. It was implanted in cadaver tibiae and subjected to fatigue cycling in combined compression and bending at physiologic levels to 21,061 cycles. This duration is estimated to represent 12 weeks of gait by the animal. Before and after fatigue cycling, monotonic testing was performed in compression and bending at physiologic levels. The intact contralateral limbs served as controls. All limbs completed the cycling; the instrumented limbs exhibited interfragmentary cyclic strain amplitudes during fatigue (616 +/- 139 micro-strain), which was significantly greater than the control limbs (136 +/- 35 microstrain). Monotonic strain amplitudes for the test limbs in bending and compression were 4839 +/- 1028 and 542 +/- 122 microstrain, respectively; corresponding values for the control bones were 407 +/- 118 and 95 +/- 38 microstrain, respectively. These data are similar to those presented in prior studies in larger bone models. The current study presents one method for interlocked nail fixation for this complex tibial shaft fracture in a small animal. 相似文献
60.
Norman Makoto Su Hiroko N. Wilensky David F. Redmiles 《Computer Supported Cooperative Work (CSCW)》2012,21(2-3):111-162
We explore how the notion of communities of practice (CoPs) was translated and popularized from its original inception by Lave and Wenger in 1991. We argue that the Institute for Research on Learning (IRL), a spin-off of Xerox PARC, proved instrumental in enrolling CoPs into the knowledge management (KM) discipline. IRL objectified, packaged, and made a business out of CoPs. CoPs in KM are now a formalized process coupled with technological artifacts to build groups of people who effectively share knowledge across boundaries. Drawing from participant observations, archival documents, and interviews with KM practitioners in the aerospace industry as well as key players of IRL, our research seeks to unveil the invisible history that the popularization of a theory can often obscure. We argue that CoPs provide a case study for understanding how abstract concepts in science are strategically and subconsciously reified, or made objects of inquiry, and appropriated by actors. This reification of a “soft” science blurs the line between theory and technology. 相似文献