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排序方式: 共有280条查询结果,搜索用时 15 毫秒
151.
152.
Anthony C. Marriott Brian K. Dove Catherine J. Whittaker Christine Bruce Kathryn A. Ryan Thomas J. Bean Emma Rayner Geoff Pearson Irene Taylor Stuart Dowall Jenna Plank Edmund Newman Wendy S. Barclay Nigel J. Dimmock Andrew J. Easton Bassam Hallis Nigel J. Silman Miles W. Carroll 《PloS one》2014,9(4)
Ferrets are widely used to study human influenza virus infection. Their airway physiology and cell receptor distribution makes them ideal for the analysis of pathogenesis and virus transmission, and for testing the efficacy of anti-influenza interventions and vaccines. The 2009 pandemic influenza virus (H1N1pdm09) induces mild to moderate respiratory disease in infected ferrets, following inoculation with 106 plaque-forming units (pfu) of virus. We have demonstrated that reducing the challenge dose to 102 pfu delays the onset of clinical signs by 1 day, and results in a modest reduction in clinical signs, and a less rapid nasal cavity innate immune response. There was also a delay in virus production in the upper respiratory tract, this was up to 9-fold greater and virus shedding was prolonged. Progression of infection to the lower respiratory tract was not noticeably delayed by the reduction in virus challenge. A dose of 104 pfu gave an infection that was intermediate between those of the 106 pfu and 102 pfu doses. To address the hypothesis that using a more authentic low challenge dose would facilitate a more sensitive model for antiviral efficacy, we used the well-known neuraminidase inhibitor, oseltamivir. Oseltamivir-treated and untreated ferrets were challenged with high (106 pfu) and low (102 pfu) doses of influenza H1N1pdm09 virus. The low dose treated ferrets showed significant delays in innate immune response and virus shedding, delayed onset of pathological changes in the nasal cavity, and reduced pathological changes and viral RNA load in the lung, relative to untreated ferrets. Importantly, these observations were not seen in treated animals when the high dose challenge was used. In summary, low dose challenge gives a disease that more closely parallels the disease parameters of human influenza infection, and provides an improved pre-clinical model for the assessment of influenza therapeutics, and potentially, influenza vaccines. 相似文献
153.
BP ONeill TM Habermann TE Witzig M Rodriguez 《Cancer immunology, immunotherapy : CII》1999,16(3):211-215
Five patients at risk for primary central nervous system lymphoma (PCNSL) recurrence were treated with high-dose methylprednisolone,
(HDMP) to prevent ‘trafficking’ of malignant lymphocytes into the central nervous system (CNS). HDMP was chosen because of
its ability to stabilize the ‘blood brain barrier (BBB)’. Three men with newly diagnosed PCNSL, ages 62, 76 and 78 y, whose
survival was projected to be 6.6 months, began treatment after achieving complete response (CR) to initial radiation therapy
alone and survived 27, 37 and 59 months after treatment. In none was death from recurrent disease in CNS but one patient did
die of systemic non-Hodgkin’s lymphoma (NHL) five years after PCNSL diagnosis. A 20 y old man was treated with HDMP after
successful combined modality therapy and is alive 75+months after initial diagnosis without evidence of disease recurrence.
A 34 y old man relapsed after combined modality initial treatment and failed to respond to HDMP when treatment was begun after
unsuccessful salvage therapy; he died of disease 12 months after initial diagnosis. There were no treatment complications.
The promising results in this pilot study from the basis for a North Central Cancer Treatment Group (NCCTG) 96-73-51, a Phase
2 clinical trial of brain radiotherapy and HDMP for PCNSL patients 70 y of age and older, a group of patients at high risk
for toxicity from intensive combined modality therapy. 相似文献
154.
Summary The change in concentration of a solute in soil, moving near the surface of a root by both mass flow and diffusion, has been calculated by a numerical method with a computer. The effect of change in the plant controlled variables v0 (the solvent flux at the root surface) and k (the root absorbing power), and the soil variables b (the buffer power) and D (the diffusion coefficient) are described in turn.The concentration at the root surface, relative to the undisturbed soil solution, approaches a limiting value v0/k. As v0 is increased, the limiting value is approached more rapidly, and the zone of disturbance is more compressed. A steady state is reached if r0v0/bD>2, but if r0v0/bD<2 the disturbance continues to spread outwards even though the concentration at the root surface has nearly attained its limiting value.As k is increased, other factors being constant, the limiting relative concentration at the root surface is approached more rapidly, but the spread of the disturbance away from the root is little affected.As Db is decreased, corresponding to a decrease in soil moisture, the concentration at the root surface reaches its limit more rapidly and the zone of disturbance is compressed.If, because of increase in the concentration at the root surface, the efficiency of root absorption declines, the relative concentration will exceed v0/k, and may reach no limit — at least until the assumptions of the model used break down. 相似文献
155.
McKim Marriott 《American anthropologist》1963,65(6):1366-1369
156.
157.
A novel beta-lactamase, conferring resistance to ceftazidime, has been identified to be encoded by a 31 kb plasmid (pUK720) in a clinical E. coli strain isolated in Belgium. The beta-lactamase, new designated TEM-E1, has a pI of approximately 5.4 and lies in between the iso-electric focused bands of the beta-lactamases TEM-1 and TEM-7. The TEM-E1 beta-lactamase has a similar molecular weight of 22,000 to the TEM-1 and it is also inhibited by clavulanic acid. However, the TEM-E1 enzyme differs from TEM-1 by its low rates and efficiency of hydrolysis for ceftazidime and cefotaxime, TEM-E1 has similar efficiency of hydrolysis values for ceftazidime and cefotaxime, but only confers resistance to ceftazidime. 相似文献
158.
159.
Thom Bitter Imran Khan Tim Marriott Elaine Lovelady Nico Verdonschot Dennis Janssen 《Computer methods in biomechanics and biomedical engineering》2013,16(13):1061-1072
AbstractFretting and corrosion at the taper-head interface in total hip arthroplasty has been reported as a potential cause of early failure of the implant system. The finite element (FE) method can be used to study the mechanics at the taper junction that are difficult to assess experimentally. Taper mismatch is one of the factors that can influence the performance of the taper junction. In this study we have assessed the effect of taper mismatch, in combination with assembly force on the volumetric wear. The study showed that higher assembly forces and smaller mismatches result in the least volumetric wear. 相似文献
160.
Pattama Senthong Christopher L. Millington Oliver J. Wilkinson Andrew S. Marriott Amanda J. Watson Onrapak Reamtong Claire E. Eyers David M. Williams Geoffrey P. Margison Andrew C. Povey 《Nucleic acids research》2013,41(5):3047-3055
The consumption of red meat is a risk factor in human colorectal cancer (CRC). One hypothesis is that red meat facilitates the nitrosation of bile acid conjugates and amino acids, which rapidly convert to DNA-damaging carcinogens. Indeed, the toxic and mutagenic DNA adduct O6-carboxymethylguanine (O6-CMG) is frequently present in human DNA, increases in abundance in people with high levels of dietary red meat and may therefore be a causative factor in CRC. Previous reports suggested that O6-CMG is not a substrate for the human version of the DNA damage reversal protein O6-methylguanine-DNA methyltransferase (MGMT), which protects against the genotoxic effects of other O6-alkylguanine lesions by removing alkyl groups from the O6-position. We now show that synthetic oligodeoxyribonucleotides containing the known MGMT substrate O6-methylguanine (O6-MeG) or O6-CMG effectively inactivate MGMT in vitro (IC50 0.93 and 1.8 nM, respectively). Inactivation involves the removal of the O6-alkyl group and its transfer to the active-site cysteine residue of MGMT. O6-CMG is therefore an MGMT substrate, and hence MGMT is likely to be a protective factor in CRC under conditions where O6-CMG is a potential causative agent. 相似文献