全文获取类型
收费全文 | 334篇 |
免费 | 30篇 |
专业分类
化学工业 | 71篇 |
金属工艺 | 23篇 |
机械仪表 | 9篇 |
建筑科学 | 17篇 |
能源动力 | 25篇 |
轻工业 | 45篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 25篇 |
一般工业技术 | 63篇 |
冶金工业 | 36篇 |
原子能技术 | 2篇 |
自动化技术 | 43篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 16篇 |
2019年 | 19篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 22篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 25篇 |
2012年 | 18篇 |
2011年 | 31篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 19篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 14篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有364条查询结果,搜索用时 203 毫秒
1.
In this study, the effect of pendant pyrene on the optical and electronic properties of poly(2,5‐dithienylpyrrole)s was studied. For this purpose a new pyrene coupled 2,5‐dithienylpyrrole derivative (SNS‐pyrene) was synthesized through click reaction. SNS‐pyrene was electrochemically polymerized and its electrochemical and optical properties were investigated by electrochemical and optical techniques. The polymer had a band gap of 3.36 eV and displayed light green to blue color variation upon oxidation in less than 2.48 s. Additionally, electrochemical copolymerization of SNS‐pyrene with 3,4‐ethylenedioxythiophene was achieved whilst a detailed investigation was performed on the effect of electrochemical polymerization conditions on the optoelectronic properties of the copolymers. Studies revealed that the copolymers exhibit multichromic reversible redox behavior with lower band gaps and shorter switching times than their parent polymer, P(SNS‐pyrene) © 2014 Society of Chemical Industry. 相似文献
2.
A method for the time suboptimal control of an industrial manipulator from an initial position and orientation to a final
position and orientation as it moves along a specified path is proposed. Nonlinear system equations that describe the manipulator
motion are linearized at each time step along the path. A method which gives the control inputs (joint angular velocities)
for time suboptimal control of the manipulator is developed. In the formulation, joint angular velocity and acceleration limitations
are also taken into consideration. A six degree of freedom elbow type manipulator is used in numerical examples to verify
the method developed. 相似文献
3.
A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemistry. The chemical structure of OThiophenePS was characterized by nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopies. Electrochemical polymerization of pyrrole with OThiophenePS was performed resulting in polypyrrole-attached, polyhedral oligomeric silsesquioxane (OPS–PPy). The spectroelectrochemical studies show that the electrochromic properties of (OPS–PPy) are superior to those of polypyrrole (PPy). This great improvement can be attributed to the more accessible doping sites and the facile ion movement during the redox switching brought by the loose packing of the PPy chains. 相似文献
4.
Ugur Ozdemir Yucel Orkut Aktas Aslihan Vuruskan Yasin Dereli Ahmed Farabi Tarhan Karaca Demirbag Ahmet Erdem Ganime Duygu Kalaycioglu Ibrahim Ozkol Gokhan Inalhan 《Journal of Intelligent and Robotic Systems》2014,74(1-2):371-393
For the last four decades Unmanned Air Vehicles (UAVs) have been extensively used for military operations that include tracking, surveillance, active engagement with weapons and airborne data acquisition. UAVs are also in demand commercially due to their advantages in comparison to manned vehicles. These advantages include lower manufacturing and operating costs, flexibility in configuration depending on customer request and not risking the pilot on demanding missions. Even though civilian UAVs currently constitute 3 % of the UAV market, it is estimated that their numbers will reach up to 10 % of the UAV market within the next 5 years. Most of the civilian UAV applications require UAVs that are capable of doing a wide range of different and complementary operations within a composite mission. These operations include taking off and landing from limited runway space, while traversing the operation region in considerable cruise speed for mobile tracking applications. This is in addition to being able traverse in low cruise speeds or being able to hover for stationary measurement and tracking. All of these complementary and but different operational capabilities point to a hybrid unmanned vehicle concept, namely the Vertical Take-Off and Landing (VTOL) UAVs. In addition, the desired UAV system needs to be cost-efficient while providing easy payload conversion for different civilian applications. In this paper, we review the preliminary design process of such a capable civilian UAV system, namely the TURAC VTOL UAV. TURAC UAV is aimed to have both vertical take-off and landing and Conventional Take-off and Landing (CTOL) capability. TURAC interchangeable payload pod and detachable wing (with potential different size variants) provides capability to perform different mission types, including long endurance and high cruise speed operations. In addition, the TURAC concept is to have two different variants. The TURAC A variant is an eco-friendly and low-noise fully electrical platform which includes 2 tilt electric motors in the front, and a fixed electric motor and ducted fan in the rear, where as the TURAC B variant is envisioned to use high energy density fuel cells for extended hovering time. In this paper, we provide the TURAC UAV’s iterative design and trade-off studies which also include detailed aerodynamic and structural configuration analysis. For the aerodynamic analysis, an in-house software including graphical user interface has been developed to calculate the aerodynamic forces and moments by using the Vortex Lattice Method (VLM). Computational Fluid Dynamics (CFD) studies are performed to determine the aerodynamic effects for various configurations For structural analysis, a Finite Element Model (FEM) of the TURAC has been prepared and its modal analysis is carried out. Maximum displacements and maximal principal stresses are calculated and used for streamlining a weight efficient fuselage design. Prototypes have been built to show success of the design at both hover and forward flight regime. In this paper, we also provide the flight management and autopilot architecture of the TURAC. The testing of the controller performance has been initiated with the prototype of TURAC. Current work focuses on the building of the full fight test prototype of the TURAC UAV and aerodynamic modeling of the transition flight. 相似文献
5.
Pingkun Yan Wuxia Zhang Baris Turkbey Peter L. Choyke Xuelong Li 《Computer Vision and Image Understanding》2013,117(9):1017-1026
Organ shape plays an important role in clinical diagnosis, surgical planning and treatment evaluation. Shape modeling is a critical factor affecting the performance of deformable model based segmentation methods for organ shape extraction. In most existing works, shape modeling is completed in the original shape space, with the presence of outliers. In addition, the specificity of the patient was not taken into account. This paper proposes a novel target-oriented shape prior model to deal with these two problems in a unified framework. The proposed method measures the intrinsic similarity between the target shape and the training shapes on an embedded manifold by manifold learning techniques. With this approach, shapes in the training set can be selected according to their intrinsic similarity to the target image. With more accurate shape guidance, an optimized search is performed by a deformable model to minimize an energy functional for image segmentation, which is efficiently achieved by using dynamic programming. Our method has been validated on 2D prostate localization and 3D prostate segmentation in MRI scans. Compared to other existing methods, our proposed method exhibits better performance in both studies. 相似文献
6.
Acceptance testing is a time-consuming task for complex software systems that have to fulfill a large number of requirements.
To reduce this effort, we have developed a widely automated method for deriving test plans from requirements that are expressed
in natural language. It consists of three stages: annotation, clustering, and test plan specification. The general idea is
to exploit redundancies and implicit relationships in requirements specifications. Multi-viewpoint techniques based on RM-ODP
(Reference Model for Open Distributed Processing) are employed for specifying the requirements. We then use linguistic analysis
techniques, requirements clustering algorithms, and pattern-based requirements collection to reduce the total effort of testing
against the requirements specification. In particular, we use linguistic analysis for extracting and annotating the actor,
process and object of a requirements statement. During clustering, a similarity function is computed as a measure for the
overlap of requirements. In the test plan specification stage, our approach provides capabilities for semi-automatically deriving
test plans and acceptance criteria from the clustered informal textual requirements. Two patterns are applied to compute a
suitable order of test activities. The generated test plans consist of a sequence of test steps and asserts that are executed
or checked in the given order. We also present the supporting prototype tool TORC, which is available open source. For the
evaluation of the approach, we have conducted a case study in the field of acceptance testing of a national electronic identification
system. In summary, we report on lessons learned how linguistic analysis and clustering techniques can help testers in understanding
the relations between requirements and for improving test planning. 相似文献
7.
Our research aim is to develop interactions and algorithms for learning from naïve human teachers through demonstration. We introduce a novel approach to leverage the goal-oriented nature of human teachers by learning an action model and a goal model simultaneously from the same set of demonstrations. We use robot motion data to learn an action model for executing the skill. We use a generic set of perceptual features to learn a goal model and use it to monitor the executed action model. We evaluate our approach with data from 8 naïve teachers demonstrating two skills to the robot. We show that the goal models in the perceptual feature space are consistent across users and correctly recognize demonstrations in cross-validation tests. We additionally observe that a subset of users were not able to teach a successful action model whereas all of them were able to teach a mostly successful goal model. When the learned action models are executed on the robot, the success was on average 66.25 %. Whereas the goal models were on average 90 % correct at deciding on success/failure of the executed action, which we call monitoring. 相似文献
8.
Lale A. Ertuglu Atalay Demiray Carlo Basile Baris Afsar Adrian Covic Mehmet Kanbay 《Hemodialysis international. International Symposium on Home Hemodialysis》2021,25(4):433-446
Sodium and ultrafiltration profiling are method of dialysis in which dialysate sodium concentration and ultrafiltration rate are altered during the course of the dialysis session. Sodium and ultrafiltration profiling have been used, commonly simultaneously, to improve hemodynamic stability during hemodialysis. Sodium profiling is particularly effective in decreasing the incidence of intradialytic hypotension, while ultrafiltration profiling is suggested to decrease subclinical repeated end organ ischemia during dialysis. However, complications such as increased interdialytic weight gain and thirst due to sodium excess have prevented widespread use of sodium profiling. Evidence suggest that different sodium profiling techniques may lead to different clinical results, and preferring sodium balance neutral sodium profiling may mitigate adverse effects related to sodium overload. However, evidence is lacking on the long-term clinical outcomes of different sodium profiling methods. Optimal method of sodium profiling as well as the utility of sodium/ultrafiltration profiling in routine practice await further clinical investigation. 相似文献
9.
Didem Ag Seleci Viktor Maurer Firat Baris Barlas Julian Cedric Porsiel Bilal Temel Elcin Ceylan Suna Timur Frank Stahl Thomas Scheper Georg Garnweitner 《International journal of molecular sciences》2021,22(9)
The development of multifunctional nanoscale systems that can mediate efficient tumor targeting, together with high cellular internalization, is crucial for the diagnosis of glioma. The combination of imaging agents into one platform provides dual imaging and allows further surface modification with targeting ligands for specific glioma detection. Herein, transferrin (Tf)-decorated niosomes with integrated magnetic iron oxide nanoparticles (MIONs) and quantum dots (QDs) were formulated (PEGNIO/QDs/MIONs/Tf) for efficient imaging of glioma, supported by magnetic and active targeting. Transmission electron microscopy confirmed the complete co-encapsulation of MIONs and QDs in the niosomes. Flow cytometry analysis demonstrated enhanced cellular uptake of the niosomal formulation by glioma cells. In vitro imaging studies showed that PEGNIO/QDs/MIONs/Tf produces an obvious negative-contrast enhancement effect on glioma cells by magnetic resonance imaging (MRI) and also improved fluorescence intensity under fluorescence microscopy. This novel platform represents the first niosome-based system which combines magnetic nanoparticles and QDs, and has application potential in dual-targeted imaging of glioma. 相似文献
10.
Baris Ozyer Ismet Erkmen Aydan M. Erkmen 《Journal of Intelligent and Robotic Systems》2014,75(2):173-191
A fully immersed object, suspended in water can be rotated from distance by a preshaped robot hand approaching and closing upon the object prior to contacting it. Momentum transfer from robot fingers closing into a grasp, to the fluid medium particles, and from these particles to the object surface generates the motion tendencies of that object in terms of rotational and translational displacements. In this paper, we propose the novel concept of a controller that determines either: 1) given initial position and orientation of a robot hand, what preshape is suitable for generating a desired momentum distribution on the surface of a given object in order to trigger a desired rotation in a desired direction when approaching with this preshaped hand; or 2) given a predetermined hand preshape, what initial position, orientation and hand aperture are suitable to generate a desired rotation upon approach and, without causing the retroceeding of the object. The desired object motion generated from distance by the approach of a hand preshape is to be used seamlessly for the subsequent manipulation of the object upon grasp. Towards this end, we propose in our work, a new model based on computational fluid dynamics, for determining the continuity in momentum transfer from robot hand fingers to the fluid medium, and to the object, until landing on that immersed object. Our experimental results demonstrate how different hand preshapes initiated from different locations in the medium surrounding an object of different cross sections suspended in equilibrium in the fluid, affects its motion tendencies in terms of rotation and translation. Our further contribution, in this paper, includes the modelling of robot fingers and object as fluidic elements which rigidity can be relaxed to induce compliance. 相似文献