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991.
Piotr Szweda Marta Schielmann Roman Kotlowski Grzegorz Gorczyca Magdalena Zalewska Slawomir Milewski 《Applied microbiology and biotechnology》2012,96(5):1157-1174
Bacteria of the genus Staphylococcus are common pathogens responsible for a broad spectrum of human and animal infections and belong to the most important etiological factors causing food poisoning. Because of rapid increase in the prevalence of isolation of staphylococci resistant to many antibiotics, there is an urgent need for the development of new alternative chemotherapeutics. A number of studies have recently demonstrated the strong potential of peptidoglycan hydrolases (PHs) to control and treat infections caused by this group of bacteria. PHs cause rapid lysis and death of bacterial cells. The review concentrates on enzymes hydrolyzing peptidoglycan of staphylococci. Usually, they are characterized by high specificity to only Staphylococcus aureus cell wall components; however, some of them are also able to lyse cells of other staphylococci, e.g., Staphylococcus epidermidis-human pathogen of growing importance and also other groups of bacteria. Some PHs strengthen the bactericidal or bacteriostatic activity of common antibiotics, and as a result, they should be considered as component of combined therapy which could definitely reduced the development of bacterial resistance to both enzymes and antibiotics. The preliminary research revealed that most of these enzymes can be produced using heterologous, especially Escherichia coli expression systems; however, still much effort is required to develop more efficient and large-scale production technologies. This review discusses current state on knowledge with emphasis on the possibilities of application of PHs in the context of therapeutics for infections caused by staphylococci. 相似文献
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The aim of this research is to investigate amphotericin B (AmB)–Cu2+ complexes in aqueous solution at different pH values. Electronic absorption, circular dichroism (CD), Raman and FTIR spectroscopies
were used in this study. We found that different concentrations of AmB and Cu2+ ions in solution leads to formation of complexes with stoichiometry of 2:1 and 1:1. The formation of AmB–Cu2+ complexes at physiological pH values is accompanied by changes of the molecular organization of AmB especially disaggregation.
These observed effects might be significant from a medical point of view. 相似文献
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Grzegorz Iszkuło Anna K. Jasińska Marian J. Giertych Adam Boratyński 《Plant Ecology》2009,200(2):229-240
Sex ratio and sexual dimorphism were studied in the dioecious tree Taxus baccata. We examined five populations of T. baccata in Poland and Ukraine to identify the differences between male and female individuals. The sex of all individuals, height
and diameter, needle length and area, specific leaf area (SLA), the number of stomata rows, stomatal density, and content
of carbon and nitrogen were measured to identify the differences between male and female individuals. The relationship between
sex ratio and climatic conditions, age and population size were analysed using data collected from the field and the literature.
Female trees were shorter than males, but needles of females were longer and had larger area. Although there were no differences
among sexes in SLA, nitrogen and carbon concentration, we found a positive correlation between nitrogen concentration and
SLA among females. The sex ratio changed with tree height within populations, and taller height classes were biased in favour
of males. Regardless of population age, the percentage of females within populations was positively correlated with precipitation.
Probably high reproductive effort caused female trees to lose in competition with males, and this loss may also be enhanced
by lower drought tolerance in females and could contribute to risk of extinction for T. baccata. The continental geographic range of T. baccata may be restricted by limited occurrence of females, which demand higher water resources than males. 相似文献
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Grzegorz Czerwonka Dawid Gmiter Anna Guzy Patrycja Rogala Agnieszka Jabłońska-Wawrzycka Andrzej Borkowski 《Biofouling》2019,35(1):59-74
Pseudomonas aeruginosa biofilm-associated infections are a serious medical problem, and new compounds and therapies acting through novel mechanisms are much needed. Herein, the authors report a ruthenium(IV) complex that reduces P. aeruginosa PAO1 biofilm formation by 84%, and alters biofilm morphology and the living-to-dead cell ratio at 1?mM concentration. Including the compound in the culture medium altered the pigments secreted by PAO1, and fluorescence spectra revealed a decrease in pyoverdine. Scanning electron microscopy showed that the ruthenium complex did not penetrate the bacterial cell wall, but accumulated on external cell structures. Fluorescence quenching experiments indicated strong binding of the ruthenium complex to both plasmid DNA and bovine serum albumin. Formamidopyrimidine DNA N-glycosylase (Fpg) protein digestion of plasmid DNA isolated after ruthenium(IV) complex treatment revealed the generation of oxidative stress, which was further proved by the observed upregulation of catalase and superoxide dismutase gene expression. 相似文献
1000.
Barbara Czochralska Wiesław Kawczynski Grzegorz Bartosz David Shugar 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,801(3):403-409
It has been shown that direct excitation of NADH (or NADPH) in aqueous medium at 254 nm, or at wavelengths longer than 320 nm (where only the reduced nicotinamide moiety absorbs), leads to generation of NAD+ (or NADP+). The reaction proceeds both in the presence and absence of oxygen. Under aerobic conditions the reaction is accompanied by formation of H2O2 at a level equimolar with that of the NADH present in solution. On irradiation at wavelengths longer than 320 nm, conversion of NADH to enzymatically active NAD+ is about 75%. Under analogous irradiation conditions, the dimers (NAD)2 and (NADP)2 undergo disproportionation to NAD+ and NADP+, respectively, to the extent of 90%. Both physicochemical and enzymatic criteria were employed to formulate mechanisms for the photooxidation of NADH and the photodisproportionation of the dimer (NAD)2. 相似文献