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排序方式: 共有436条查询结果,搜索用时 562 毫秒
421.
Proper interpretation of the thyroid gland functional data is an important issue in the diagnosis of thyroid disease. The primary role of the thyroid gland is to help regulation of the body’s metabolism. Thyroid hormone produced by the thyroid gland provides this. Production of too little thyroid hormone (hypothyroidism) or production of too much thyroid hormone (hyperthyroidism) defines the type of thyroid disease. Artificial immune systems (AISs) is a new but effective branch of artificial intelligence. Among the systems proposed in this field so far, artificial immune recognition system (AIRS), which was proposed by A. Watkins, has shown an effective and intriguing performance on the problems it was applied. This study aims at diagnosing thyroid disease with a new hybrid machine learning method including this classification system. By hybridizing AIRS with a developed Fuzzy weighted pre-processing, a method is obtained to solve this diagnosis problem via classifying. The robustness of this method with regard to sampling variations is examined using a cross-validation method. We used thyroid disease dataset which is taken from UCI machine learning respiratory. We obtained a classification accuracy of 85%, which is the highest one reached so far. The classification accuracy was obtained via a 10-fold cross-validation. 相似文献
422.
Operation sequencing has been a key area of research and development for computer-aided process planning (CAPP). An optimal process sequence could largely increase the efficiency and decrease the cost of production. Genetic algorithms (GAs) are a technique for seeking to ‘breed’ good solutions to complex problems by survival of the fittest. Some attempts using GAs have been made on operation sequencing optimization, but few systems have intended to provide a globally optimized fitness function definition. In addition, most of the systems have a lack of adaptability or have an inability to learn. This paper presents an optimization strategy for process sequencing based on multi-objective fitness: minimum manufacturing cost, shortest manufacturing time and best satisfaction of manufacturing sequence rules. A hybrid approach is proposed to incorporate a genetic algorithm, neural network and analytical hierarchical process (AHP) for process sequencing. After a brief study of the current research, relevant issues of process planning are described. A globally optimized fitness function is then defined including the evaluation of manufacturing rules using AHP, calculation of cost and time and determination of relative weights using neural network techniques. The proposed GA-based process sequencing, the implementation and test results are discussed. Finally, conclusions and future work are summarized. 相似文献
423.
Kemal Ulutas Sahin Yakut Deniz Bozoglu Mehtap Irem Tankul Deniz Deger 《应用聚合物科学杂志》2024,141(14):e55185
Hydroxyethyl cellulose (HEC) thin films with a molecular weight of 720,000 g/mol deposited by thermal evaporation in a thickness range of 250, 500, and 750 nm were measured in a frequency range of 1–105 Hz and a temperature range of 233–373 K for dielectric characterization with increments of 10 K. Dielectric results were used to derive and evaluate the glass transition temperature and ductility, which are essential parameters for structural analysis. Results showed that the thickness of HEC thin films was an effective parameter on dielectric and structural properties. Because of the increasing thickness, the dielectric constant has values between 22 and 143 at 1 kHz, and glass transition temperature and ductility change between 211–175 K and 15–20, respectively. Based on the literature and the compatible results, the main effect of these variations could be dead layers and voids in structure. The effect of the dead layer gave an important idea about the adjustability of mechanical properties of HEC thin films depending on the thickness. In this way, it would be possible to use these thin films deposited from HEC with 720,000 g/mol molecular weight, especially in drug delivery, electrophoresis technologies, biomedical devices, and coverage applications. 相似文献
424.
Oksan Karal-Yilmaz Abdulkadir Ozkan Emel Akgun Manolya Kukut Kemal Baysal Timucin Avsar Turker Kilic 《Journal of materials science. Materials in medicine》2013,24(1):147-153
Poly(lactic-co-glycolic acid) microspheres loaded with imatinib mesylate has been developed as a new therapeutic strategy to prevent craniopharyngioma recurrence. Microspheres composed of different lactic/glycolic acid ratios, molecular weights and drug compositions were synthesized and loaded with imatinib mesylate by modified double-emulsion/solvent evaporation technique and subsequently characterized by particle-size distribution, scanning electron microscopy, encapsulation efficiency and in vitro drug release. Inhibitory potential of imatinib containing microspheres on tumor neovascularization was investigated on craniopharyngioma tumor samples by rat cornea angiogenesis assay. Results showed that microspheres in different LA:GA ratios [LA:GA 50:50 (G50), 75:25 (G25), 85:15 (G15)] considerably reduced neovascularization induced by recurrent tumor samples in an in vivo angiogenesis assay (P < 0.01). Our data indicate that local delivery of imatinib mesylate to the post-surgical tumoral cavity using biodegradable microspheres may be a promising biologically selective approach to prevent the recurrence of craniopharyngiomas, via inhibition of neovascularization. 相似文献
425.
Sezai K��t��k S��leyman Bolat Kemal ?zt��rk ?enol Akbulut O?uzhan ?ak?r 《Journal of Superconductivity and Novel Magnetism》2011,24(1-2):475-479
A precursor YBCO in the stoichiometric ratio of 1:2:3 was prepared by the flame-quench-melt-growth (FQMG) method. Both the superconducting and nonsuperconducting regions were decided by measuring the magnetic levitation force per unit volume as a function of thickness of the superconducting sample. It was determined that superconducting forming ratio depends on where it forms in the sample, and thus a region near the top surface of the sample contains more superconducting forming ratio than the other regions. The levitation force density measured at different thicknesses of the sample ranging from 6.54 to 1.58 mm firstly increased and then separately reached a saturation point (maximum value) for both repulsive and attractive levitation force density. It was found that the maximum values of the repulsive and attractive levitation forces were respectively 125 mN/cm3 and ?23 mN/cm3. The considerably improved F L ?z performance in FQMG sample can be translated to large-scale Y123 blocks intended for real superconducting levitation applications. 相似文献
426.
Serpil ?akiro?lu Kemal Kocaba? 《Journal of Superconductivity and Novel Magnetism》2011,24(4):1321-1325
The effect of Ag substitution on the properties of high-temperature superconductor Bi1.7Pb0.3Sr2Ca2−x
Ag
x
Cu3O
y
system have been investigated. The electrical and structural properties of the samples, prepared by the conventional solid-state
reaction method, have been characterized by X-ray diffraction (XRD), electrical resistance and scanning electron microscopy
(SEM) studies. XRD analysis reveals a multiphase structure of the samples, whereas SEM micrographs indicate some morphological
changes induced by silver addition. It was found that an increase of the amount of Ag2O addition leads to an enhancement of the critical temperature and the percentage of Bi-2223 phase in the phase mixture. 相似文献
427.
Exergy analysis of a single-effect lithium bromide/water absorption system for cooling and heating applications is presented in this paper. Exergy loss, enthalpy, entropy, temperature, mass flow rate and heat rate in each component of the system are evaluated. From the results obtained it can be concluded that the condenser and evaporator heat loads and exergy losses are less than those of the generator and absorber. This is due to the heat of mixing in the solution, which is not present in pure fluids. Furthermore, a simulation program is written and used for the determination of the coefficient of performance (COP) and exergetic efficiency of the absorption system under different operating conditions. The results show that the cooling and heating COP of the system increase slightly when increasing the heat source temperature. However, the exergetic efficiency of the system decreases when increasing the heat source temperature for both cooling and heating applications. 相似文献
428.
The first-principles calculations based on the density-functional theory have been performed using both the generalized–gradient approximation (GGA) and the local-density approximation (LDA) to investigate many physical properties of NaIn and NaTl compounds. Specifically, the structural (lattice constant, bulk modulus, pressure derivative of bulk modulus, phase transition pressure (Pt)), mechanical (second-order elastic constants (Cij), Young’s modulus, isotropic shear modulus, Zener anisotropy factor, Poisson’s ratio, sound velocities), thermo dynamical (cohesive energy, formation enthalpy, Debye temperature), and the vibrational properties (phonon dispersion curves and one-phonon density of states) are calculated and compared with the available experimental and other theoretical data. Also, we have presented the temperature variations of various thermo dynamical properties such as free energy, internal energy, entropy and heat capacity for the same compounds. 相似文献
429.
Tomas Bolumar Vibeke Orlien Anita Sikes Kemal Aganovic Kathrine H. Bak Claire Guyon Anna-Sophie Stübler Marie de Lamballerie Christian Hertel Dagmar A. Brüggemann 《Comprehensive Reviews in Food Science and Food Safety》2021,20(1):332-368
High-pressure processing (HPP) has been the most adopted nonthermal processing technology in the food industry with a current ever-growing implementation, and meat products represent about a quarter of the HPP foods. The intensive research conducted in the last decades has described the molecular impacts of HPP on microorganisms and endogenous meat components such as structural proteins, enzyme activities, myoglobin and meat color chemistry, and lipids, resulting in the characterization of the mechanisms responsible for most of the texture, color, and oxidative changes observed when meat is submitted to HPP. These molecular mechanisms with major effect on the safety and quality of muscle foods are comprehensively reviewed. The understanding of the high pressure–induced molecular impacts has permitted a directed use of the HPP technology, and nowadays, HPP is applied as a cold pasteurization method to inactive vegetative spoilage and pathogenic microorganisms in ready-to-eat cold cuts and to extend shelf life, allowing the reduction of food waste and the gain of market boundaries in a globalized economy. Yet, other applications of HPP have been explored in detail, namely, its use for meat tenderization and for structure formation in the manufacturing of processed meats, though these two practices have scarcely been taken up by industry. This review condenses the most pertinent-related knowledge that can unlock the utilization of these two mainstream transformation processes of meat and facilitate the development of healthier clean label processed meats and a rapid method for achieving sous vide tenderness. Finally, scientific and technological challenges still to be overcome are discussed in order to leverage the development of innovative applications using HPP technology for the future meat industry. 相似文献
430.
Wood can be protected from attack by pests with preservative treatment of the many different preservatives available for wood; borates are generally preferred for indoor uses and can be used to treat solid wood and engineered wood composites. Although treated panels make up a large part of the plywood market, treatment with some wood preservatives has been known to interfere with the bond integrity of glued wood specimens. In this study, the possible effects of borax and boric acid treatment on adhesive wettability and surface roughness of veneers and bond strength and hygroscopicity of plywood panels were tested. No clear changes in surface roughness after borax and boric acid treatment were observed. Poor wettability on the surfaces of alder and beech veneers with UF resin after borate treatments was obtained. Bond strength values of plywood panels decreased and equilibrium moisture content (EMC) of plywood panels increased after borate treatment. 相似文献