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101.
从资源紧缺、环境污染、产品低端等方面,总结了我国钒、钛、镍、钴、锂稀有金属资源在战略性新兴产业迅猛发展时代所面临的国家重大需求,回顾了领域近年来通过升级和变革传统稀有金属资源利用技术取得的主要进展和成就。其中煤基钠化冶炼、高温碳化?低温氯化、亚熔盐氧化等非常规介质强化手段是实现钒钛磁铁矿中钒、钛绿色高值高效利用的核心;盐酸常压浸出?低温选择性水解?共沉淀新技术是一种低成本、短流程高效高值利用红土镍矿全组分的先进技术代表;双功能协同复合萃取原理是实现高镁盐湖卤水的锂资源绿色利用的关键基础。基于固废资源化和源头减废两个思路,现阶段战略性金属资源的利用技术初步解决了环境污染和资源利用率低的问题,但仍存在资源绿色利用基础原理匮乏、产品科技含量低等普遍问题。以战略性产业关键材料为导向的绿色高值利用技术的应用基础研究是稀有金属相关绿色产业战略性发展的重要科技保障,是未来重要的前沿研究方向。 相似文献
102.
Anisotropic metal nanoparticles have been paid much attention because the broken symmetry of these nanoparticles often leads
to novel properties. Anisotropic gold nanoparticles obtained by wet chemical methods inevitably accompany spherical ones due
to the intrinsically high symmetry of face-centred cubic metal. Therefore, it is essential for the purification of anisotropic
gold nanoparticles. This work presents a facile, low cost while effective solution to the challenging issue of high-purity
separation of seed-mediated grown NIR-responsive gold nanorods from co-produced spherical and cubic nanoparticles in solution.
The key point of our strategy lies in different shape-dependent solution stability between anisotropic nanoparticles and symmetric
ones and selective self-assembly and subsequent precipitation can be induced by introducing ions to the as-made nanorod solution.
As a result, gold nanorods of excellent purity (97% in number density) have been obtained within a short time, which has been
confirmed by SEM observation and UV-vis-NIR spectroscopy respectively. Based on the experimental facts, a possible shape separation
mechanism was also proposed. 相似文献
103.
Pourceau G Chevolot Y Goudot A Giroux F Meyer A Moulés V Lina B Cecioni S Vidal S Yu H Chen X Ferraris O Praly JP Souteyrand E Vasseur JJ Morvan F 《Chembiochem : a European journal of chemical biology》2011,12(13):2071-2080
Influenza neuraminidases hydrolyze the ketosidic linkage between N-acetylneuraminic acid and its adjacent galactose residue in sialosides. This enzyme is a tetrameric protein that plays a critical role in the release of progeny virions. Several methods have been described for the determination of neuraminidase activity, usually based on colorimetric, fluorescent, or chemiluminescent detection. However, only a few of these tests allow discrimination of the sialyl-linkage specificity (i.e., α2-3- versus α2-6-linked sialyllactosides) of the neuraminidase. Herein we report a glycoarray-based assay and a MALDI-TOF study for assessing the activity and specificity of two influenza neuraminidases on whole viruses. The human A(H3N2) and avian A(H5N2) neuraminidase activities were investigated. The results from both approaches demonstrated that α2-3 sialyllactoside was a better substrate than α2-6 sialyllactoside for both viruses and that H5N2 virus had a lower hydrolytic activity than H3N2. 相似文献
104.
In this paper, we employed a facile hydrothermal route to successfully synthesize nanosized nickel phosphide particles with controlled phases via selecting different surfactants at different temperatures and times. The phases of the as-obtained products were determined by X-ray powder diffraction (XRD) patterns and Rietveld refinement of XRD data. The morphologies of the products were characterized by (high resolution) transmission electron microscopy (HR/TEM) and field emission scanning electron microscopy (FESEM). Experiments indicated that pure Ni2P phase could be prepared when nontoxic red phosphorus and nickel dichloride were used as starting materials in the presence of polyvinylpyrrolidone (PVP, 30 K), sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB) or polyethylene glycol 10000 (PEG-10000) at 160 °C for 10 h. When acrylamide (AM) was selected as the surfactant, however, pure Ni12P5 phase could be prepared by prolonging the reaction time to 20 h at 160 °C, or enhancing the reaction temperature to 180 °C for 10 h. Furthermore, the experiments indicated that the pure Ni2P phase possessed a stronger photocatalytic degradation ability than the pure Ni12P5 phase. 相似文献
105.
通过微波法化学镀镍对纳米碳纤维(CNFs)进行表面改性,采用熔融共混法制备CNFs/低密度聚乙烯(LDPE)纳米复合材料,在模压硫化过程中施加磁场,实现表面镀镍CNFs在LDPE基体中的取向,研究了CNFs的掺杂对CNFs/LDPE纳米复合材料结晶性能的影响,采用场发射扫描电子显微镜(FE-SEM)观察刻蚀后样品中CNFs分散、取向情况和球晶形貌,采用X射线衍射仪(XRD)分析纳米复合材料结晶性能。研究发现,在LDPE基体中CNFs的掺杂对纳米复合材料结晶性能有着较大的影响;掺杂CNFs使LDPE的结晶度下降,且掺杂样品需较长时间的刻蚀才能看到清晰的球晶结构,LDPE的球晶结构较明显,其直径约6μm,CNTs的取向使纳米复合材料的结晶度增大。 相似文献
106.
Aprahamian M Bour G Akladios CY Fylaktakidou K Greferath R Soler L Marescaux J Egly JM Lehn JM Nicolau C 《Chembiochem : a European journal of chemical biology》2011,12(5):777-783
Myo-inositol trispyrophosphate (ITPP), a synthetic allosteric effector of hemoglobin, increases the regulated oxygen-releasing capacity of red blood cells (RBCs), leading to suppression of hypoxia-inducible factor 1α (HIF-1α) and to down-regulation of hypoxia-inducible genes such as vascular endothelial growth factor (VEGF). As a consequence, tumor growth is markedly affected. The effect of weekly intravenous injection of ITPP on an orthotopic, syngenic rat hepatocellular carcinoma (HCC) model was compared to that for untreated animals and animals subjected to conventional Doxorubicin chemotherapy. The longitudinal examination of HCC was performed by microCT imaging, and the cellular and molecular changes were evaluated by histology and Western blotting analysis of HIF-1α, VEGF, and caspase-3 gene expression in the tumor and in the surrounding liver. Hematologic impact was evaluated by blood cell-count measurement and determination of P50 (oxygen partial pressure for a 50 % oxygen saturation of hemoglobin). The HCC evaluation by microCT revealed a high potency of ITPP for tumor growth inhibition, thus allowing long-term survival and even cure of almost all the treated animals. The P50 value of hemoglobin in RBCs underwent a shift of 30 % following ITPP injection. Under these conditions, HIF-1α activity was strongly decreased, VEGF expression was down-regulated, and apoptosis was induced in HCC and surrounding liver cells, as indicated by Caspase-3 expression. ITPP did not affect hematologic parameters during treatment. The observations of in vivo tumor eradication suggest a significant clinical potential for ITPP in cancer therapy. 相似文献
107.
108.
Florian FabreGilles Hétreux Jean-Marc Le LannPascale Zaraté 《Computers & Chemical Engineering》2011,35(10):2098-2112
Simulation is now a CAPE tool widely used by practicing engineers for process design and control. In particular, it allows various offline analyses to improve system performance such as productivity, energy efficiency, waste reduction, etc. In this framework, we have developed the dynamic hybrid simulation environment PrODHyS whose particularity is to provide general and reusable object-oriented components dedicated to the modeling of devices and operations found in chemical processes. Unlike continuous processes, the dynamic simulation of batch processes requires the execution of control recipes to achieve a set of production orders. For these reasons, PrODHyS is coupled to a scheduling module (ProSched) based on a MILP mathematical model in order to initialize various operational parameters and to ensure a proper completion of the simulation. This paper focuses on the procedure used to generate the simulation model corresponding to the realization of a scenario described through a particular scheduling. 相似文献
109.
采用电石渣和盐湖氯化镁为原料制取氢氧化镁。电石渣(氢氧化钙)与氯化铵反应生成氨气,将氨气通入氯化镁溶液中制备氢氧化镁。通过单因素实验和正交实验得出最佳工艺条件:氯化铵与氯化镁物质的量比为5.0,氯化镁浓度为2.0 mol/L,反应时间为60 min,反应温度为25 ℃,陈化时间为2 h。在该条件下氢氧化镁的生成率可达到89%,纯度也可达到98%以上。通过X射线衍射(XRD)及扫描电镜(SEM)表征表明,氢氧化镁产品为片状,粒径在800 nm左右。采用该方法制备氢氧化镁,不仅可以解决电石渣和盐湖氯化镁的大量堆放问题,而且可以制备出高品质的氢氧化镁产品。 相似文献
110.