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71.
Human bone marrow (BM) failure mediated by the immune system can be modeled in mice. In the present study, infusion of lymph node (LN) cells from C57BL/6 mice into C.B10-H2(b)/LilMcd (C.B10) recipients that are mismatched at multiple minor histocompatibility Ags, including the immunodominant Ag H60, produced fatal aplastic anemia. Declining blood counts correlated with marked expansion and activation of CD8 T cells specific for the immunodominant minor histocompatibility Ag H60. Infusion of LN cells from H60-matched donors did not produce BM failure in C.B10 mice, whereas isolated H60-specific CTL were cytotoxic for normal C.B10 BM cells in vitro. Treatment with the immunosuppressive drug cyclosporine abolished H60-specific T cell expansion and rescued animals from fatal pancytopenia. The development of BM failure was associated with a significant increase in activated CD4+CD25+ T cells that did not express intracellular FoxP3, whereas inclusion of normal CD4+CD25+ regulatory T cells in combination with C57BL/6 LN cells aborted H60-specific T cell expansion and prevented BM destruction. Thus, a single minor histocompatibility Ag H60 mismatch can trigger an immune response leading to massive BM destruction. Immunosuppressive drug treatment or enhancement of regulatory T cell function abrogated this pathophysiology and protected animals from the development of BM failure.  相似文献   
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Direct non-insect-vector transmission of Leishmania parasites in mice   总被引:1,自引:0,他引:1  
Animal to animal non-vector transmission of Leishmania major was investigated in Balb/c mice, a strain known for its susceptibility to this parasite. Both overt or inapparent infection (documented by positive spleen cultures) was possible after prolonged contact with infected animals. Similarly transmission of infection from infected mothers to their offspring was documented.  相似文献   
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A new ligand LH (where LH = N-(picolinoyl)-biurate) has been prepared and characterized. The presence of three amide linkages make this ligand sufficiently flexible to act as N,N,O donor tridentate blocking ligand in the formation of a one dimensional metal-ligand layer like structure. Reaction of LH and dicyanamide (dca) with Co(NO3)2 · 6H2O gives [CoL(dca)]n (1). In this compound picolinamide modulated ligand L coordinated the central Co(II) ion in a meridonal-fashion. The single crystal X-ray crystallography revealed that in 1, dca acts as μ1,5− singly bridging ligand whereas μ1,5− doubly bridging is the more common type. This gives rise to the 1D undulated waves like structure. The Co(II) centre is surrounded in a distorted square pyramidal coordination geometry. The variable temperature magnetic (VTM) susceptibility measurements show that the global feature of the χMT versus T curve for 1 is characteristic of very weak antiferromagnetic interactions through the dicyanamide ligand and between 300 and 5 K the best fit parameter was determined as J = −3.52 cm−1. The X-ray structure, VTM study and UV-Vis spectrum of the compound show that 1 is a low-spin square-pyramidal compound whereas high-spin compounds are more common for the five coordinated cobalt (II) compounds. The X-band EPR spectrum of 1 at room temperature shows only one isotropic band centred at g = 2.08.  相似文献   
75.
Irritable bowel syndrome (IBS) is a prolonged and disabling functional gastrointestinal disorder with the incidence rate of 18% in the world. IBS could seriously affect lifetime of patients and cause high economic burden on the community. The pathophysiology of the IBS is hardly understood, whereas several possible mechanisms, such as visceral hypersensitivity, irregular gut motility, abnormal brain–gut relations, and the role of infectious agents, are implicated in initiation and development of this syndrome. Different studies demonstrated an alteration in B-lymphocytes, mast cells (MC), T-lymphocytes, and cytokine concentrations in intestinal mucosa or systemic circulation that are likely to contribute to the formation of the IBS. Therefore, IBS could be developed in those with genetic predisposition. Infections’ role in initiation and exacerbation of IBS has been investigated by quite several clinical studies; moreover, the possible role of some pathogens in development and exacerbation of this disease has been described. It appears that the main obligatory pathogens correspond with the IBS disease, Clostridium difficile, Escherichia coli, Mycobacterium avium subspecies paratuberculosis, Campylobacter concisus, Campylobacter jejuni, Chlamydia trachomatis, Helicobacter pylori, Pseudomonas aeruginosa, Salmonella spp, Shigella spp, and viruses, particularly noroviruses. A number of pathogenic parasites (Blastocystis, Dientamoeba fragilis, and Giardia lamblia) may also be involved in the progression and exacerbation of the disease. Based on the current knowledge, the current study concludes that the most common bacterial, viral, and parasitic pathogens may be involved in the development and progression of IBS.  相似文献   
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Purpose

This paper presents the implementation of O-LCA by a Brazilian cosmetics manufacturer. The case study was developed within the framework of the road testing of the “Guidance on organizational LCA” of the UNEP/SETAC Life Cycle Initiative. The aim is to illustrate methodological choices and implementation challenges encountered by the company, i.e., related to the broad product portfolio. The study demonstrates that O-LCA allows quantifying and managing environmental impacts throughout global supply chains and for every individual product.

Methods

O-LCA provides the methodological framework for applying LCA to organizations, and a set of application options based on the structure and experience of organizations. The reporting organization is NATURA Brazil in 2013. The 2600 products in the portfolio are modeled in this first exercise of the company through the bestsellers at each of its ten product category groups. A hybrid approach is considered for data collection: top-down approach for modeling corporate activities and bottom-up approach for upstream and downstream life cycle phases. The data sources are NATURA’s recordings, data gathered from suppliers, estimates from mass and energy balances, and life cycle inventory databases. The approach to acquire direct data or use life cycle databases depends on the representativeness of each raw material or packaging.

Results and discussion

The results show that major impacts could be detected during use phase that demands water and energy to use rinse-off products (the use phase of NATURA’s products contributed over 41% to most impact categories), and in the supply chain, and generated during the obtaining of plant origin ingredients and materials for packaging. Overall, the whole NATURA had in 2013 a potential impact on climate change of 1.4 million tonnes of CO2 eq, a natural land transformation of 1.3 million m2, and a fossil depletion of 0.23 million tonnes of oil eq, among other impacts. Apart from the results at the organizational level, individual results for product bestsellers were calculated and are presented here.

Conclusions

The study confirmed the applicability of the O-LCA model at NATURA, addressed operational issues related to broad product portfolios, considering several dimensions such as data quality and availability, LCA software, and data management. Despite NATURA’s existing practices and previous knowledge in modeling environmental impacts of products and corporate activities, managing the large amount of data involved prove being a complex task. The company identified gaps and opportunities able to guide future method implementation and LCA-based management.

  相似文献   
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A new design for the multilayer superlens, with the sub-wavelength imaging ability for various 2D objects in the visible range, is introduced and analyzed. The designed superlens will be more versatile for practical applications. A rigorous and efficient approach based on the method of moments is used to study the imaging performance of this structure. The imaging performance of the proposed superlens is evaluated using the correlation coefficient. In this work, the closed-form dyadic Green’s functions in spatial domain, needed for the method of moments solutions, are obtained by applying the complex image method. Besides, the numerical integration is exploited to verify this method. The imaging results obtained via our approach are examined by comparison with the finite element method simulations that reveal good efficiency and accuracy of the proposed method.  相似文献   
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