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981.
The Yeast ATF1 Acetyltransferase Efficiently Acetylates Insect Pheromone Alcohols: Implications for the Biological Production of Moth Pheromones
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Bao-Jian Ding Ida Lager Sunil Bansal Timothy P. Durrett Sten Stymne Christer Löfstedt 《Lipids》2016,51(4):469-475
Many moth pheromones are composed of mixtures of acetates of long‐chain (≥10 carbon) fatty alcohols. Moth pheromone precursors such as fatty acids and fatty alcohols can be produced in yeast by the heterologous expression of genes involved in insect pheromone production. Acetyltransferases that subsequently catalyze the formation of acetates by transfer of the acetate unit from acetyl‐CoA to a fatty alcohol have been postulated in pheromone biosynthesis. However, so far no fatty alcohol acetyltransferases responsible for the production of straight chain alkyl acetate pheromone components in insects have been identified. In search for a non‐insect acetyltransferase alternative, we expressed a plant‐derived diacylglycerol acetyltransferase (EaDAcT) (EC 2.3.1.20) cloned from the seed of the burning bush (Euonymus alatus) in a yeast system. EaDAcT transformed various fatty alcohol insect pheromone precursors into acetates but we also found high background acetylation activities. Only one enzyme in yeast was shown to be responsible for the majority of that background activity, the acetyltransferase ATF1 (EC 2.3.1.84). We further investigated the usefulness of ATF1 for the conversion of moth pheromone alcohols into acetates in comparison with EaDAcT. Overexpression of ATF1 revealed that it was capable of acetylating these fatty alcohols with chain lengths from 10 to 18 carbons with up to 27‐ and 10‐fold higher in vivo and in vitro efficiency, respectively, compared to EaDAcT. The ATF1 enzyme thus has the potential to serve as the missing enzyme in the reconstruction of the biosynthetic pathway of insect acetate pheromones from precursor fatty acids in yeast. 相似文献
982.
Analyzing market performance via social media has attracted a great deal of attention in the finance and machine-learning disciplines.However,the vast majority of research does not consider the enormous influence a crisis has on social media that further affects the relationship between social media and the stock market.This article aims to address these challenges by proposing a multistage dynamic analysis framework.In this framework,we use an authorship analysis technique and topic model method to identify stakeholder groups and topics related to a special firm.We analyze the activities of stakeholder groups and topics in different periods of a crisis to evaluate the crisis’s influence on various social media parameters.Then,we construct a stock regression model in each stage of crisis to analyze the relationships of changes among stakeholder groups/topics and stock behavior during a crisis.Finally,we discuss some interesting and significant results,which show that a crisis affects social media discussion topics and that different stakeholder groups/topics have distinct effects on stock market predictions during each stage of a crisis. 相似文献
983.
984.
Susanna K. P. Lau Kim-Chung Lee George C. S. Lo Vanessa S. Y. Ding Wang-Ngai Chow Tony Y. H. Ke Shirly O. T. Curreem Kelvin K. W. To Deborah T. Y. Ho Siddharth Sridhar Sally C. Y. Wong Jasper F. W. Chan Ivan F. N. Hung Kong-Hung Sze Ching-Wan Lam Kwok-Yung Yuen Patrick C. Y. Woo 《International journal of molecular sciences》2016,17(3)
To identify potential biomarkers for improving diagnosis of melioidosis, we compared plasma metabolome profiles of melioidosis patients compared to patients with other bacteremia and controls without active infection, using ultra-high-performance liquid chromatography-electrospray ionization-quadruple time-of-flight mass spectrometry. Principal component analysis (PCA) showed that the metabolomic profiles of melioidosis patients are distinguishable from bacteremia patients and controls. Using multivariate and univariate analysis, 12 significant metabolites from four lipid classes, acylcarnitine (n = 6), lysophosphatidylethanolamine (LysoPE) (n = 3), sphingomyelins (SM) (n = 2) and phosphatidylcholine (PC) (n = 1), with significantly higher levels in melioidosis patients than bacteremia patients and controls, were identified. Ten of the 12 metabolites showed area-under-receiver operating characteristic curve (AUC) >0.80 when compared both between melioidosis and bacteremia patients, and between melioidosis patients and controls. SM(d18:2/16:0) possessed the largest AUC when compared, both between melioidosis and bacteremia patients (AUC 0.998, sensitivity 100% and specificity 91.7%), and between melioidosis patients and controls (AUC 1.000, sensitivity 96.7% and specificity 100%). Our results indicate that metabolome profiling might serve as a promising approach for diagnosis of melioidosis using patient plasma, with SM(d18:2/16:0) representing a potential biomarker. Since the 12 metabolites were related to various pathways for energy and lipid metabolism, further studies may reveal their possible role in the pathogenesis and host response in melioidosis. 相似文献
985.
随着科学技术的发展和经济水平的提高,人们对消防安全的认识日益增强.需要重视消防安全,做好消防管理,并采用先进的管理模式,在当前的消防管理模式下应用"智能消防",可以确保人民生命财产安全提供强有力的支持,使现代科学技术可以更好地融入到消防工作中,不仅可以提高火灾监控能力,还可以提高消防水平,对消防安全领域的发展具有重要意义,使传统消防逐步向智能消防转变,并不断升级. 相似文献
986.
987.
This article considers the output synchronisation of a class of networked agents. Each agent is a passive system. Local information, used by each agent to adjust its movement, forms a network with switching adjacent topology. First, we consider the asymptotic stability of switched non-linear time-varying systems with delayed measurement feedback by using multiple Lyapunov function. A Barbalat-like lemma is obtained. Then the result is applied to the output synchronisation of a class of networked passive systems with switching topology. A verifiable sufficient condition is presented. 相似文献
988.
989.
990.
The purpose of this study was to characterize the properties of stable and reinforced protein–polysaccharides complex coacervations firstly formed by electrostatic interaction between WPI and beet pectin, and followed by laccase cross-linking through ferulic acid present in beet pectin. The interaction of whey protein isolate (WPI, 6 g/100 ml) with beet pectin (0–0.16 g/100 ml) in aqueous solutions was studied at different pH (3–7). ζ-potential and light-scattering techniques were used to provide information about the electrical charge and aggregation of individual biopolymers and complex coacervations. Stable WPI/beet pectin complex coacervations were formed when system consisted of 6 g/100 ml WPI and 1 g/100 ml beet pectin at pH 3.5. The microstructure and viscoelastic properties of WPI and beet pectin complex coacervations in the presence of laccase (0, 100, 300 U) was also studied using FT-IR, rheology, and confocal laser scanning microscopy (CLSM) techniques. The results obtained clearly showed that laccase catalyzed cross-linking of ferulic acid present in beet pectin had a remarkable influence on the physical properties of WPI–beet pectin complex coacervations microstructure. The reinforced complex coacervations formed fine networking structures which may provide convenient means for food industry to incorporate bioactive components into food products. 相似文献