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51.
Dye-sensitized solar cells (DSSCs) were assembled by using the bougainvillea flowers, red turnip and the purple wild Sicilian prickly pear fruit juice extracts as natural sensitizers of TiO2 films. The yellow orange indicaxanthin and the red purple betacyanins are the main components in the cocktail of natural dyes obtained from these natural products. The best overall solar energy conversion efficiency of 1.7% was obtained, under AM 1.5 irradiation, with the red turnip extract, that showed a remarkable current density (Jsc = 9.5 mA/cm2) and a high IPCE value (65% at λ = 470 nm). Also the purple extract of the wild Sicilian prickly pear fruit showed interesting performances, with a Jsc of 9.4 mA/cm2, corresponding to a solar to electrical power conversion of 1.26%.  相似文献   
52.
The biobehavioral consequences of psychogenic stress were examined using neuroendocrine and ethological methods in a captive colony of common marmosets (Callithrix jacchus jacchus). Specifically, hypothalamic-pituitary-adrenal (HPA) axis reactivity was evaluated as a function of gender and social status in four consecutive social environments [(1) stable heterosexual pairs; (2) isolation; (3) unstable peer groups; and (4) stable peer groups], by measuring both basal plasma cortisol, adrenocorticotropic hormone (ACTH) and beta-endorphin concentrations and responsiveness of these hormones to dexamethasone, ovine corticotropin-releasing hormone (oCRH), and ACTH1-24. Socially stressful conditions, such as isolation and peer group formation, were associated with increased HPA axis function and behavioral arousal, and individual profiles were related to gender and social status. Hormonal levels prior to group formation predicted subsequent status in peer groups. Basal morning concentrations of plasma cortisol, as well as cortisol responsiveness to dexamethasone suppression, were sensitive indices of HPA axis arousal during periods of social stress. The context-dependent development of hormonal and behavioral profiles, reminiscent of depression and/or anorexia nervosa, suggests that the common marmoset may be a useful model of psychiatric hypercortisolism.  相似文献   
53.
In this paper we have investigated the role of Egr-1 in B cell growth regulation by examining the gene expression in a panel of B cell lines, including both EBV genome negative and EBV carrying cell lines. Egr-1 expression correlates with the cellular phenotype and the specific pattern of viral latency established within the individual cell lines. Thus, constitutive activation of Egr-1 gene is invariably associated with unrestricted expression of viral latent genes in all group III EBV genome carrying cell lines. In contrast, Egr-1 expression is abrogated in group I Burkitt tumor cells, irrespective of the EBV genome carrying status. Activated viral gene expression associated with phenotypic conversion of group I cell lines in to group II or III restores the Egr-1 gene expression. Several forms of EGR-1 protein are found within the different groups of cell lines, and the binding activity to DNA consensus sequences was investigated. Finally, time course analysis of Egr-1 expression during the early steps of EBV infection in vitro demonstrated that Egr-1 is upregulated within minutes from the initial interaction with the B lymphocyte.  相似文献   
54.
This paper is concerned with the direct dynamic analysis of mechanisms comprising flexible members. It is first recalled how the time integration of the dynamic equations governing the motion of a flexible mechanism is conditioned by the availability of the so-called iteration matrix. The latter is obtained not only from the mass matrix, which is sufficient in the rigid case, but also from the stiffness and damping tangent matrices. Hence, in a context based upon relative co-ordinates where the deformation of the flexible bodies is described by component modes, two formulations, a classical one and a new one, which permit the determination of this iteration matrix are presented. The classical formulation is based upon the Lagrange's theorem. The new one consists in a direct calculation of the residues of the dynamic equations by using the inverse method of Newton–Euler. In this case, the iteration matrix is obtained by a numerical derivation technique which proves well-conditioned. A first simple example is treated in order to compare the two formulations. A more complex one illustrates the real capabilities of the new formulation.  相似文献   
55.
A simple concept for storing and retrieving geographic data has been developed. It has been implemented in FORTRAN and BASIC and each package was developed for machine independence. The FORTRAN package is used for highway location studies and interpolating ground heights for highway design.  相似文献   
56.
57.
Alcohol ethoxylates are versatile surfactants because both the hydrophobic and the hydrophilic moieties can be varied readily to change performance. Many studies have focused on the effect of changes in the average length of the hydrophobe and the nature of the hydrophile. Less frequently studied, however, has been the effect on performance of hydrophobe structure, yet this can be varied easily by changing the alcohol feedstock used to make the alcohol ethoxylate. This study compares the performance of alcohol ethoxylates derived from oleochemical alcohol and oxo-alcohols derived from kerosene, butylene, or coal by the Fischer-Tropsch process. Two aspects of hydrophobe structure were found to be important for performance of alcohol ethoxylates: the overall linearity of the parent alcohol and the degree of substitution at the C2 carbon. As the linearity of the parent alcohol increases, the critical micelle concentration (CMC) decreases and the surface tension at the CMC increases. Increasing substitution at the C2 carbon increases the amount of unethoxylated alcohol in the ethoxylate but decreases the inverse cloud point temperature, wetting time, and foam stability in the absence of soil.  相似文献   
58.
The prevalence of idiopathic male infertility is high, up to 75% of patients with abnormal sperm parameters. Hence, the research of its causes is mandatory. Oxidative stress (OS) can be responsible for male infertility in 30–80% of cases. In recent years, seminal plasma (SP) proteomics has developed as a useful tool to provide biomarkers of specific diseases. This systematic review aims to collect the available evidence on the changes of SP proteome in patients exposed to OS to provide possible SP biomarkers of sperm OS. To accomplish this, the following keyterms “seminal fluid proteome”, “seminal plasma proteome”, “oxidative stress”, and “sperm oxidative stress” were used and 137 records were found. Among these, 17 were finally included. Nine proteins involved with OS were found overexpressed in patients with OS. Twenty-three proteins were found differentially expressed in patients with clinical conditions associated with OS, such as varicocele, male accessory gland infection/inflammation, cigarette smoke, and obesity. These proteins do not seem to overlap among the clinical conditions taken into account. We speculate that specific SP proteins may mediate OS in different clinical conditions. Altogether, these results suggest that proteomics could help to better understand some of the molecular mechanisms involved in the pathogenesis of infertility. However, further studies are needed to identify potential biomarkers of male infertility with valuable clinical significance.  相似文献   
59.
Positron emission tomography (PET) is a non-invasive molecular imaging technology that is constantly expanding, with a high demand for specific antibody-derived imaging probes. The use of tracers based on temperature-sensitive molecules (i. e. Fab, svFab, nanobodies) is increasing and has led us to design a class of chelators based on the structure of 2-aminomethylpiperidine (AMP) with acetic and/or hydroxybenzyl pendant arms (2-AMPTA, NHB-2-AMPDA, and 2-AMPDA-HB), which were investigated as such for {Al18F}2+-core chelation efficiency. All the compounds were characterized by HPLC-MS analysis and NMR spectroscopy. The AlF-18 labeling reactions were performed under various conditions (pH/temperature), and the radiolabeled chelates were purified and characterized by radio-TLC and radio-HPLC. The stability of labeled chelates was investigated up to 240 min in human serum (HS), EDTA 5 mM, PBS and 0.9 % NaCl solutions. The in vivo stability of [Al18F(2-AMPDA-HB)] was assessed in healthy nude mice (n=6). Radiochemical yields between 55 % and 81 % were obtained at pH 5 and room temperature. High stability in HS was measured for [Al18F(2-AMPDA-HB)], with 90 % of F-18 complexed after 120 min. High stability in vivo, rapid hepatobiliary and renal excretion, with low accumulation of free F-18 in bones were measured. Thus, this new Al18F-chelator may have a great impact on immuno-PET radiopharmacy, by facilitating the development of new fluorine-18-labeled heat-sensitive biomolecules.  相似文献   
60.
Coronavirus disease 2019 (COVID-19) is induced by SARS-CoV-2 and may arise as a variety of clinical manifestations, ranging from an asymptomatic condition to a life-threatening disease associated with cytokine storm, multiorgan and respiratory failure. The molecular mechanism behind such variability is still under investigation. Several pieces of experimental evidence suggest that genetic variants influencing the onset, maintenance and resolution of the immune response may be fundamental in predicting the evolution of the disease. The identification of genetic variants behind immune system reactivity and function in COVID-19 may help in the elaboration of personalized therapeutic strategies. In the frenetic look for universally shared treatment plans, those genetic variants that are common to other diseases/models may also help in addressing future research in terms of drug repurposing. In this paper, we discuss the most recent updates about the role of immunogenetics in determining the susceptibility to and the history of SARS-CoV-2 infection. We propose a narrative review of available data, speculating about lessons that we have learnt from other viral infections and immunosenescence, and discussing what kind of aspects of research should be deepened in order to improve our knowledge of how host genetic variability impacts the outcome for COVID-19 patients.  相似文献   
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