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51.
Based on the rapid increase in incidence of inflammatory bowel disease (IBD), the identification of susceptibility genes and cell populations contributing to this condition is essential. Previous studies suggested multiple genes associated with the susceptibility of IBD; however, due to the analysis of whole-tissue samples, the contribution of individual cell populations remains widely unresolved. Single-cell RNA sequencing (scRNA-seq) provides the opportunity to identify underlying cellular populations. We determined the enrichment of Crohn’s disease (CD)-induced genes in a publicly available Crohn’s disease scRNA-seq dataset and detected the strongest induction of these genes in innate lymphoid cells (ILC1), highly activated T cells and dendritic cells, pericytes and activated fibroblasts, as well as epithelial cells. Notably, these genes were highly enriched in IBD-associated neoplasia, as well as sporadic colorectal cancer (CRC). Indeed, the same six cell populations displayed an upregulation of CD-induced genes in a CRC scRNA-seq dataset. Finally, after integrating and harmonizing the CD and CRC scRNA-seq data, we demonstrated that these six cell types display a gradual increase in gene expression levels from a healthy state to an inflammatory and tumorous state. Together, we identified cell populations that specifically upregulate CD-induced genes in CD and CRC patients and could, therefore, contribute to inflammation-associated tumor development.  相似文献   
52.
Abstract

The co‐ordination between theory and evidence is an outstanding characteristic of scientific thinking. Research indicates that students often have difficulty in explaining natural phenomena because they use their own theories to explain phenomena or they are unable to build a bridge between theory and evidence. Science teachers must teach students to collect and select evidence and to use theory to explain it. The objective of this study was to investigate the forms of reasoning used by prospective physical sciences teachers when they build up explanations and make predictions about natural phenomena. Thirty‐eight prospective teachers answered a questionnaire structured around three problems focusing on phenomena that can be explained through air‐pressure variation. The results seem to indicate a variation in the forms of reasoning used, depending on the problem and the type of request. The number of prospective teachers who consistently use a certain form of reasoning is higher within problems than across problems.  相似文献   
53.
Doped and undoped hematite films for photoelectrochemical hydrogen production were prepared by spin-coating deposition solution (SCDS). To understand the influence of the Si-doping and identify the critical parameters of the proposed SCDS method an extensive characterization was conducted. The Si-doped hematite exhibited higher photocurrent response when compared with undoped films. We have shown that the crystallographic orientation degree of the films appears to be a dominant factor affecting the photocurrent. The performance of our hematite electrodes is well below the maximum theoretical efficiency and the conceivable explanation could be given by the high value of recombination phenomena (electron/hole pair).  相似文献   
54.
The structural stability of the pigment was investigated using X-ray diffraction coupled with SEM and UV–vis–IR analysis, as a function of the relative Co content and calcination temperature. A standard formulation prepared from commercial reagents was also prepared and characterized for the sake of comparison. The pigment was added to a transparent glaze and to a porcelain stoneware body. Since the relative amount of cobalt was low and the sintering temperature of the pigment was not too high (1350–1400 °C), the new pigment system offers an interesting alternative to spinel, olivine and willemite commercial blue pigments. Moreover, the use of several wastes in the pigment formulation does not diminish its colouring performance.  相似文献   
55.

The aim of this study was to apply the PIXE (Particle Induced X-ray Emission) and PDMS (Plasma Desorption Mass Spectrometry) techniques to characterize airborne dust particles containing metals. Aerosols generated at a mineral-sand processing plant were characterized in this study. The aerosol samples were collected at a plant that processes mineral sands to obtain rutile, ilmenite, zircon, and monazite concentrates. A cascade impactor with six stages was used to collect mineral dust particles with aerodynamic diameters in the range of 0.64 to 19.4 mum. The particles impacted on each stage of the cascade impactor were analyzed by PIXE, which permits the determination of the elemental mass air concentration and the MMAD (Mass Median Aerodynamic Diameter). The chemical compositions of the aerosol samples were identified by PDMS analysis. This study shows that, by using PIXE and PDMS techniques, it is possible to determine the chemical compounds in which the elements are associated in the aerosol particles. Based on the results of the PIXE analysis, the elemental mass concentrations and the MMADs were determined.  相似文献   
56.
Increasing use of petroleum, coupled with concern for global warming, demands the development and institution of CO2 reducing, non-fossil fuel-based alternative energy-generating strategies. Ethanol is a potential alternative, particularly when produced in a sustainable way as is envisioned for sugarcane in Brazil. We consider the expansion of sugarcane-derived ethanol to displace 5% of projected gasoline use worldwide in 2025. With existing technology, 21 million hectares of land will be required to produce the necessary ethanol. This is less than 7% of current Brazilian agricultural land and equivalent to current soybean land use. New production lands come from pasture made available through improving pasture management in the cattle industry. With the continued introduction of new cane varieties (annual yield increases of about 1.6%) and new ethanol production technologies, namely the hydrolysis of bagasse to sugars for ethanol production and sugarcane trash collection providing renewable process energy production, this could reduce these modest land requirements by 29–38%.  相似文献   
57.
Here we describe a new route for the synthesis of nanometric Ni particles embedded in a mesoporous silica material with excellent potential for catalytic applications. Mesoporous silica with a surface area in the range of 202-280 m2/g, with narrow pore size distribution and Ni nanoparticles (particles in the range of 3-41 nm) were obtained in a direct process. A different approach was adopted to process such a nanocomposite. This new approach is based on the formation of a polymer with the silicon oxianion and nickel cation chelated to the macromolecule structure and on the control of the pyrolysis step. The CO/CO2 atmosphere resulting from the pyrolysis of the organic material promotes the reduction of the Ni citrate.  相似文献   
58.
The non-ohmic properties of the 98.90% SnO2+(1–x)%CoO+0.05% Cr2O3+0.05% Nb2O5+x% MnO2 varistor system (all of them in mol %), as well as the influence of the oxidizing and reducing atmosphere on this system were studied in this work. Experimental evidence indicates that the electrical properties of the varistor depend on the defects that occur at the grain boundary and on the adsorbed oxygen species such as O2, O2, O in this region. Thermal treatments at 900 °C in oxygen and nitrogen atmospheres indicated such a dependence with the values of the non-linearity coefficient () increasing under oxygen atmosphere, being reduced in nitrogen atmosphere and restored after a new treatment in oxygen atmosphere, presenting a reversibility in the process. EDS analysis accomplished by SEM showed the distribution of the oxides in the varistor matrix.  相似文献   
59.
60.
Refractory hypotension with end-organ hypoperfusion is an ominous feature of inflammatory shock. In the past fifteen years, nitric oxide (a diffusible, short-lived product of arginine metabolism) has been found to be an important regulatory molecule in several areas of metabolism, including vascular tone control. Vascular endothelial cells constitutively produce low levels of nitric oxide that regulate blood pressure by mediating adjacent smooth-muscle relaxation. In an inflammatory shock state, cytokines, like interleukin-1 and tumor necrosis factor-alpha, induce a separate, high-output form of the enzyme that synthesizes nitric oxide in both endothelial and smooth-muscle cells. The ensuing high rates of nitric oxide formation result in extensive smooth-muscle relaxation, pressor refractory vasodilation, and--ultimately--shock. The concept of the pathogenesis of inflammatory shock explains many limitations of current therapies and may foster the development of new interventions to mitigate the effects of nitric oxide overproduction in this syndrome.  相似文献   
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