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991.
To enhance the production of biohydrogen from biomass, various pretreatment methods play important role. In this study, effect of microwave irradiation on the culture was studied on biohydrogen production from Benincasa hispida (Petha) solid waste at different powers for a fixed interval of time. The highest power studied was 800 W with a frequency of 2450 MHz. The amount of soluble sugars found in the waste was 13.9 mg/L having the chemical oxygen demand (COD) of 3000 mg/L. Studies have been performed in batch reactors using mixed consortia and results were also compared with the reactor operated at the normal conditions i.e. without any inoculum pretreatment. Maximum hydrogen produced was 14 mmol H2 per mol of soluble sugar consumed in the reactor in which the inoculum was exposed to 320 W of microwave for 5 min. SEM analysis of this microwave pretreated culture was done.  相似文献   
992.
Development of low-temperature solid oxide fuel cells (LTSOFC) is now becoming a mainstream research direction worldwide. The advancement in the effective electrolyte materials has been one of the major challenges for LTSOFC development. To further improve the performance of electrolyte, composite approaches are considered as common strategies. The enhancement on ionic conductivity or sintering behavior ceria-based electrolyte can either be done by adding a carbonate phase to facilitate the utilization of the ionic-conducting interfaces, or by addition of alumina as insulator to reduce the electronic conduction of ceria. Thus the present report aims to design a composite electrolyte materials by combining the above two composite approaches, in order to enhance the ionic conductivity and to improve the long-term stability simultaneously. Here we report the preparation and investigation of GDC-KAlZn materials with composition of Gd doped ceria, K2CO3, ZnO and Al2O3. The structure and morphology of the samples were characterized by XRD, SEM, etc. The ionic conductivity of GDC-KAlZn sample was determined by impedance spectroscopy. The composite samples with various weight ratio of GDC and KAlZn were used as electrolyte material to fabricate and evaluate fuel cells as well as investigate the composition dependent properties. The good ionic conductivity and notable fuel cell performance of 480 mW cm−2 at 550 °C has demonstrated that GDC-KAlZn composite electrolyte can be regarded as a potential electrolyte material for LTSOFCs.  相似文献   
993.
Microbes secrete molecules that modify their environment. Here, we demonstrate a class of synthetic disaccharide derivatives (DSDs) that mimics and dominates the activity of naturally secreted rhamnolipids by Pseudomonas aeruginosa. The DSDs exhibit the dual function of activating and inhibiting the swarming motility through a concentration‐dependent activity reversal that is characteristic of signaling molecules. Whereas DSDs tethered with a saturated farnesyl group exhibit inhibition of both biofilm formation and swarming motility, with higher activities than rhamnolipids, a saturated farnesyl tethered with a sulfonate group only inhibits swarming motility but promote biofilm formation. These results identified important structural elements for controlling swarming motility, biofilm formation, and bacterial adhesion and suggest an effective chemical approach to control intertwined signaling processes that are important for biofilm formation and motilities.  相似文献   
994.
Gallium telluride (Ga2Te3) was synthesized at different temperatures (850 to 460° C) using different cooling rates. Materials synthesized at higher temperatures (including quenched materials from the melt) always yielded zinc-blende lattice with well resolved 1 2 doublet X-ray powder diffraction lines. In the material synthesized at lower temperature ( 460°C), we obtained additional (superlattice) lines as reported by Newman and Cundall [4]. It was possible to index these reflections not only on an orthorhombic unit cell (a=0.417, b=2.360, c=1.252 nm) but also on cubic (a=1.7678 nm) and hexagonal (a=0.832, c=3.065 nm) unit cells. To us, the hexagonal cell appears to be more realistic. If sufficient time is given to reach equilibrium, the whole of the zinc-blende form of Ga2Te3 is transformed to the hexagonal form. It has been further observed that conversion of the hexagonal into the cubic form and vice versa can be brought about by heating the material at temperatures greater or less than 460° C, respectively. Lastly, the zinc-blende phase of Ga2Te3 is metastable and slowly transforms to hexagonal form at room temperature.  相似文献   
995.
Stability of any power system is a major issue for secure operation of the system. The stability of power system is concerned with the behavior of synchronous generators following disturbances. Transmission system in competitive market refers to over loading of transmission lines or transformers due to market settlement. Thus there is a need of enhancing transmission capability of the network. FACTS controllers have the capability of controlling power flow by means of controlling line parameters, voltage injection at some of the angle. In the proposed work optimal location for installation of FACTS device is obtained using NN and the amount of voltage and angle to be injected in the system using UPFC is calculated using Bees algorithm. The method is tested on IEEE 26 bus system but it is general in nature and can be applied to any power system. The results exhibit the performance of the method in maintaining the system stability and АТС enhancement.  相似文献   
996.
997.
We report a peculiar multifocal micronodular proliferation of pneumocytes occurring in a 24-yr-old woman with tuberous sclerosis and lymphangioleiomyomatosis. A computed tomographic scan of the chest demonstrated multiple minute nodules present throughout both lung fields. Histologically, the nodules were well demarcated, measured up to 1.6 mm in diameter, and were composed of thickened, fibrotic, alveolar septa lined by pleomorphic, type II pneumocytes. Positive immunohistochemical stains for keratin, BER-EP4, and surfactant, and negative immunohistochemical staining with an antibody recognizing Clara cells support an epithelial origin from type II pneumocytes. The absence of immunohistochemical staining for HMB45 suggests a histogenesis separate than the lesions of lymphangioleiomyomatosis. We failed to detect estrogen or progesterone receptors in either the lesions of lymphangioleiomyomatosis or the micronodular proliferations. Recognition of these unique lesions facilitates their distinction from other epithelial proliferations, particularly atypical bronchioloalveolar cell hyperplasia. This lesion appears to be a distinctive manifestation of tuberous sclerosis. It is probably hamartomatous.  相似文献   
998.
In the posterior partially edentulous jaw, implants may be used to supplement existing natural dentition. Frequently, the maxillary sinuses and the mandibular nerve preclude the fabrication of freestanding implant-retained prostheses. However, if an implant and a natural abutment are combined, a fixed prosthesis can be fabricated, restoring the arch into the premolar area. The histories of three patients with attachments connecting implant-retained ceramotitanium crowns with crowns on natural abutments are described. A design for a rigid custom-made attachment for the Br?nemark system, using standard components with a machine-duplication, spark-erosion technique, is suggested.  相似文献   
999.
Results from an approach to infer surface soil moisture from time series analysis of surface wetness index derived using the Special Sensor Microwave/Imager (SSM/I) are presented. Soil moisture quantification was based on the study of temporal changes in surface wetness index and its scaling to maximum and air‐dry limits of soil in each grid cell (0.33°). The estimated soil moisture of Illinois, USA was compared with field measured soil moisture (0–10?cm) obtained from the Global Soil Moisture Data Bank. A root mean square error of 7.18% was found between estimated and measured volumetric soil moisture. A consistency in soil moisture and rainfall pattern was found in the un‐irrigated areas of northern India (Jodhpur, Varanasi) and southern India (Madurai), influenced by southwest and northeast monsoons, respectively. Soil moisture of more than 0.30 m3m?3 was observed in the absence of rainfall due to the irrigation of rice crop in (Punjab) during the pre‐southwest monsoon period (May).  相似文献   
1000.
This paper reports the feasibility of using pre-consumer processing agricultural waste to remove Cr(VI) from synthetic wastewater under different experimental conditions. For this, rice husk, has been used after pre-treatments (boiling and formaldehyde treatment). Effect of various process parameters, namely, pH, adsorbent dose, initial chromium concentration and contact time has been studied in batch systems. The removal of chromium was dependent on the physico-chemical characteristics of the adsorbent, adsorbate concentration and other studied process parameters. Maximum metal removal was observed at pH 2.0. The efficiencies of boiled and formaldehyde treated rice husk for Cr(VI) removal were 71.0% and 76.5% respectively for dilute solutions at 20gl(-1) adsorbent dose. The experimental data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. It was found that Freundlich and D-R models fitted well. The results revealed that the hexavalent chromium is considerably adsorbed on rice husk and it could be an economical method for the removal of hexavalent chromium from aqueous systems. FTIR and SEM were recorded, before and after adsorption, to explore number and position of the functional groups available for Cr(VI) binding on to studied adsorbents and changes in adsorbent surface morphology.  相似文献   
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