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Michael V. Dubina Sergey Yu. Vyazmin Vitali M. Boitsov Eugene N. Nikolaev Igor A. Popov Alexey S. Kononikhin Igor E. Eliseev Yuri V. Natochin 《Origins of life and evolution of the biosphere》2013,43(2):109-117
Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K+ is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na+, which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K+ as the driving force, not Na+, as commonly believed. 相似文献
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Vitali I. Betaneli Michael V. Ovchinnikov Leon V. Backinowsky Nikolay K. Kochetkov 《Carbohydrate research》1982,107(2):285-291
N.m.r., enzymic, and chemical techniques have been used to characterise the d-galactose-containing tri- and tetra-saccharides produced on hydrolysis of carob and L. leucocephalad-galacto-d-mannans by Driselase β-d-mannanase. These oligosaccharides were shown to be exclusively 61-α-d-galactosyl-β-d-mannobiose and 61-α-d-galactosyl-β-d-mannotriose. Furthermore, these were the only d-galactose-containing tri- and tetra-saccharides produced on hydrolysis of carob d-galacto-d-mannan by β-d-mannanases from other sources, including Bacillus subtilis, Aspergillus niger, Helix pomatia gut solution, and germinated legumes. Acid hydrolysis of lucerne galactomannan yielded 61-α-d-galactosyl-β-d-mannobiose and 62-α-d-galactosyl-β-d-mannobiose. 相似文献
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Dual roles of plcA in Listeria monocytogenes pathogenesis 总被引:26,自引:5,他引:21
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Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of preventable nosocomial infections and is endemic in hospitals worldwide. The effectiveness of infection control policies varies significantly across hospital settings. The impact of the hospital context towards the rate of nosocomial MRSA infections and the success of infection control is understudied. We conducted a modelling study to evaluate several infection control policies in surgical, intensive care, and medical ward specialties, each with distinct ward conditions and policies, of a tertiary public hospital in Sydney, Australia. We reconfirm hand hygiene as the most successful policy and find it to be necessary for the success of other policies. Active screening for MRSA, patient isolation in single-bed rooms, and additional staffing were found to be less effective. Across these ward specialties, MRSA transmission risk varied by 13% and reductions in the prevalence and nosocomial incidence rate of MRSA due to infection control policies varied by up to 45%. Different levels of infection control were required to reduce and control nosocomial MRSA infections for each ward specialty. Infection control policies and policy targets should be specific for the ward and context of the hospital. The model we developed is generic and can be calibrated to represent different ward settings and pathogens transmitted between patients indirectly through health care workers. This can aid the timely and cost effective design of synergistic and context specific infection control policies. 相似文献
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Estimation of anisotropy coefficient of swine pancreas,liver and muscle at 1064 nm based on goniometric technique 下载免费PDF全文
Paola Saccomandi Vitali Vogel Babak Bazrafshan Jürgen Maurer Emiliano Schena Thomas J. Vogl Sergio Silvestri Werner Mäntele 《Journal of biophotonics》2015,8(5):422-428
Optical properties of tissues are required for theoretical modeling of Laser Ablation in tumor therapy. The light scattering characteristic of tissues is described by the anisotropy coefficient, g. The relationship between the angular distribution of scattered light and g is given by the Henyey‐Greenstein (HG) phase function. This work describes the estimation of anisotropy coefficients of ex vivo swine pancreas, liver and muscle at 1064 nm. The intensities of scattered light at fixed angles were measured under repeatability conditions. Experimental data were fitted with a two‐term HG, estimating the anisotropy coefficients for the forward (e.g., 0.956 for pancreas, 0.964 for liver and 0.968 for muscle) and the backward (e.g., –0.481 for pancreas, –0.414 for liver and –0.372 for muscle) scattering.
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