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81.
Digital microfluidic design and optimization of classic and new fluidic functions for lab on a chip systems 总被引:2,自引:2,他引:0
Yves Fouillet Dorothée Jary Claude Chabrol Patricia Claustre Christine Peponnet 《Microfluidics and nanofluidics》2008,4(3):159-165
This paper deals with microfluidic studies for lab-on-a-chip development. The first goal was to develop microsystems immediately
usable by biologists for complex protocol integrations. All fluid operations are performed on nano-liter droplet independently
handled solely by electrowetting on dielectric (EWOD) actuation. A bottom-up architecture was used for chip design due to
the development and validation of elementary fluidic designs, which are then assembled. This approach speeds up development
and industrialization while minimizing the effort in designing and simplifying chip-fluidic programming. Dispensing reproducibility
for 64 nl droplets obtained a CV below 3% and mixing time was only a few seconds. Ease of the integration was demonstrated
by performing on chip serial dilutions of 2.8-folds, four times. The second part of this paper concerns the development of
new innovative fluidic functions in order to extend EWOD-actuated digital fluidics’ capabilities. Experiments of particle
dispensing by EWOD droplet handling are reported. Finally, work is shown concerning the coupling of EWOD actuation and magnetic
fields for magnetic bead manipulation. 相似文献
82.
Cole JN Henningham A Gillen CM Ramachandran V Walker MJ 《Proteomics. Clinical applications》2008,2(3):387-410
Gram-positive streptococci are non-motile, chain-forming bacteria commonly found in the normal oral and bowel flora of warm-blooded animals. Over the past decade, a proteomic approach combining 2-DE and MS has been used to systematically map the cellular, surface-associated and secreted proteins of human pathogenic streptococcal species. The public availability of complete streptococcal genomic sequences and the amalgamation of proteomic, genomic and bioinformatic technologies have recently facilitated the identification of novel streptococcal vaccine candidate antigens and therapeutic agents. The objective of this review is to examine the constituents of the streptococcal cell wall and secreted proteome, the mechanisms of transport of surface and secreted proteins, and describe the current methodologies employed for the identification of novel surface-displayed proteins and potential vaccine antigens. 相似文献
83.
Hoelzl C Lorenz O Haudek V Gundacker N Knasmüller S Gerner C 《Proteomics. Clinical applications》2008,2(1):108-117
Epidemiological studies indicate a correlation of cruciferous vegetables consumption with reduced incidence of cancer. This study was designed to investigate molecular mechanisms, which may help to understand the beneficial effects of Brussels sprout consumption. In order to avoid the limitations of in vitro model systems, we performed a dietary intervention study with five participants. We investigated, whether sprout consumption affects the proteome profile of primary white blood cells. In order to achieve maximal sensitivity in detecting specific adaptive proteome alterations, we metabolically labelled freshly isolated cells in the presence of 35S‐methionine/cysteine and performed autoradiographic quantification of protein synthesis. Proteins were separated by 2‐DE and spots of interest were cut out, digested and identified by MS. After the intervention, we found a significant up‐regulation of the synthesis of manganese superoxide dismutase (1.56‐fold) and significant down‐regulation of the synthesis of heat shock 70 kDa protein (hsp70; 2.27‐fold). Both proteins play a role in malignant transformation of cells. Hsp‐70 is involved in the regulation of apoptosis, which leads to elimination of cancer cells, while SOD plays a key role in protection against reactive oxygen species mediated effects. Our findings indicate that the alteration of the synthesis of these proteins may be involved in the anticarcinogenic effects of cruciferous vegetables, which was observed in earlier laboratory studies with animals. 相似文献
84.
Knowledge is increasingly recognized as the key resource of business. Digital networks provide access to vast amounts of data and information but knowledge management tools and systems are required to translate this in a meaningful way. Knowledge management initiatives are unlikely to be successful unless they are integrated with business strategy, and related to the development of the core capabilities of the organisation. Sharing the discovery and synthesis of intellectual activity involves the creation of knowledge communities of practice. There is much evidence of commercially inspired corporate initiatives in this direction across all industrial sectors: leveraging existing intellectual capital; sharing best practice across multiple locations; data mining to build customer relationships; and creating knowledge networks to allow state–of–the–art solutions in professional services. 相似文献
85.
86.
Sreng J Lécuyer A Mégard C Andriot C 《IEEE transactions on visualization and computer graphics》2006,12(5):1013-1020
This paper describes a set of visual cues of contact designed to improve the interactive manipulation of virtual objects in industrial assembly/maintenance simulations. These visual cues display information of proximity, contact and effort between virtual objects when the user manipulates a part inside a digital mock-up. The set of visual cues encloses the apparition of glyphs (arrow, disk, or sphere) when the manipulated object is close or in contact with another part of the virtual environment. Light sources can also be added at the level of contact points. A filtering technique is proposed to decrease the number of glyphs displayed at the same time. Various effects--such as change in color, change in size, and deformation of shape- can be applied to the glyphs as a function of proximity with other objects or amplitude of the contact forces. A preliminary evaluation was conducted to gather the subjective preference of a group of participants during the simulation of an automotive assembly operation. The collected questionnaires showed that participants globally appreciated our visual cues of contact. The changes in color appeared to be preferred concerning the display of distances and proximity information. Size changes and deformation effects appeared to be preferred in terms of perception of contact forces between the parts. Last, light sources were selected to focus the attention of the user on the contact areas. 相似文献
87.
Cloutier G Shung KK Durand LG 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1993,40(6):786-795
Intrinsic and nonstationary Doppler spectral broadening, and the skewness of the spectral representation, were evaluated experimentally using porcine red cell suspensions as ultrasonic scatterers. Theoretically, the relative Doppler bandwidth, defined as the intrinsic bandwidth divided by the mean Doppler frequency shift, should be velocity independent. The relative Doppler bandwidth invariance theorem was experimentally verified with an in vitro steady laminar blood flow model. It is shown that the relative bandwidth is both independent of the flow velocity and blood hematocrit. Using a pulsatile laminar flow model, the authors demonstrated that the relative Doppler bandwidth invariance theorem did not hold during flow acceleration and deceleration. In addition, a positive skewness of the Doppler spectra was observed during acceleration while a negative skewness was measured during the deceleration of blood. The effect of the window duration used in the Fourier spectral computation, on nonstationary broadening, is characterized. 相似文献
88.
O'Brien S Luo Y Wu C Petrak M Bohm E Brandt JM 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2012,226(3):235-245
The micromotion at the interface between the polyethylene tibial insert and metal tibial tray [corrected] in modular total knee replacements [corrected] has been shown to contribute to wear particle-induced osteolysis and may [corrected] cause implant failure. Therefore, studying the design parameters that are involved in the backside wear process is an important task that may lead to improvement in new total knee replacements. In the present study, a finite element model was developed to predict the backside micromotion along the entire modular interface. Both the linear elastic constitutive model and non-linear J2-plasticity constitutive model were considered in the finite element model for polyethylene and were corroborated against published results obtained from displacement controlled knee simulator wear tests. The finite element simulation with the non-linear J2-plasticity constitutive model was able to predict backside micromotion [corrected] more accurately than the simulation with the linear elastic constitutive model. [corrected] The developed finite element model (including the non-linear J2-plasticity constitutive model) was then applied to assess the effects of the tibial tray locking mechanism design (dovetails versus fullperipheral [corrected] design) and different levels of interference fit on insert micromotion. The developed finite element model, implementing the non-linear J2-plasticity constitutive model, was shown to successfully predict clinical amounts of backside micromotion and could be used for the design and development of total knee replacements for the reduction of backside micromotion and polyethylene [corrected] wear. 相似文献
89.
Riedl T Gemming T Mickel C Eymann K Kirchner A Kieback B 《Microscopy research and technique》2012,75(6):711-719
This article explores the achievable transmission electron microscopy specimen thickness and quality by using three different preparation methods in the case of a high-strength nanocrystalline Cu-Nb powder alloy. Low specimen thickness is essential for spatially resolved analyses of the grains in nanocrystalline materials. We have found that single-sided as well as double-sided low-angle Ar ion milling of the Cu-Nb powders embedded into epoxy resin produced wedge-shaped particles of very low thickness (<10 nm) near the edge. By means of a modified focused ion beam lift-out technique generating holes in the lamella interior large micrometer-sized electron-transparent regions were obtained. However, this lamella displayed a higher thickness at the rim of ≥30 nm. Limiting factors for the observed thicknesses are discussed including ion damage depths, backscattering, and surface roughness, which depend on ion type, energy, current density, and specimen motion. Finally, sections cut by ultramicrotomy at low stroke rate and low set thickness offered vast, several tens of square micrometers uniformly thin regions of ~10-nm minimum thickness. As major drawbacks, we have detected a thin coating on the sections consisting of epoxy deployed as the embedding material and considerable nanoscale thickness variations. 相似文献
90.
Ting Wang Christine Chevallereau Carlos F. Rengifo 《Robotics and Autonomous Systems》2012,60(7):962-977
This paper presents a stable walking control method for a 3D bipedal robot with 14 joint actuators. The overall control law consists of a ZMP (zero moment point) controller, a swing ankle rotation controller and a partial joint angles controller. The ZMP controller guarantees that the stance foot remains in flat contact with the ground. The swing ankle rotation controller ensures a flat foot impact at the end of the swinging phase. Each of these controllers creates 2 constraints on joint accelerations. As a consequence, the partial joint angles controller is implemented to track only 10 independent outputs. These outputs are defined as a linear combination of the 14 joint angles. The most important question addressed in this paper is how this linear combination can be defined in order to ensure walking stability. The stability of the walking gait under closed loop control is evaluated with the linearization of the restricted Poincare map of the hybrid zero dynamics. As a result, the robot can achieve an asymptotically stable and periodic walking along a straight line. Finally, another feedback controller is supplemented to adjust the walking direction of the robot and some examples of the robot steered to walk along different paths with mild curvature are given. 相似文献