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Yeh-Jin Ahn Louisa Vang Thomas A. McKeon Grace Q. Chen 《In vitro cellular & developmental biology. Plant》2007,43(1):9-15
An efficient plant regeneration protocol was established for castor (Ricinus communis L.). Hypocotyl tissue from zygotic embryo axis produced adventitious shoots when treated with either thidiazuron (TDZ, 1 μM)
or 6-benzylaminopurine (BA, 20 μM). TDZ resulted in more than a threefold higher rate of shoot induction (a maximum of 24.2
shoots per explant) than BA (6.8 shoots). Our results also showed that the pretreatment of explants in the dark increased
the number of shoots regenerated per explant by 82% and 36% with TDZ and BA, respectively. The elongation of hypocotyl tissue
in the dark appears to be the primary cause of the increase. Comparable rates of rooting were achieved on the media supplemented
with either indole-3-butyric acid (IBA, 84.3%) or 1-naphthaleneacetic acid (NAA, 87.4%) at 5 μM. However, IBA was more efficient
in promoting root and shoot development, resulting in a higher rate of establishment (93.5%) in the soil, compared to the
rate with NAA (39.5%). Histological analysis showed the adventitious induction of the shoot buds originated from the cortex
of the hypocotyl tissue. 相似文献
224.
Kanthi Kiran Kondepudi Padma Ambalam Ingrid Nilsson Torkel Wadström Åsa Ljungh 《Anaerobe》2012,18(5):489-497
Bifidobacterium breve 46, Bifidobacterium lactis 8:8 and Bifidobacterium longum 6:18 and three reference strains B. breve CCUG 24611, B. lactis JCM 10602, and Bifidobacterium pseudocatenulatum JCM 1200 were examined for acid and bile tolerance, prebiotic utilization and antimicrobial activity against four Clostridium difficile (CD) strains including the hypervirulent strain, PCR ribotype NAP1/027. B. lactis 8:8 and B. lactis JCM 10602 exhibited a high tolerance in MRSC broth with pH 2.5 for 30 min. B. breve 46 and B. lactis 8:8 remained 100% viable in MRSC broth with 5% porcine bile after 4 h. All six strains showed a high prebiotic degrading ability (prebiotic score) with galactooligosaccharides (GOS), isomaltooligosaccharides (IMOS) and lactulose as carbon sources and moderate degradation of fructooligosaccharides (FOS). Xylooligosaccharides (XOS) was metabolized to a greater extent by B. lactis 8:8, B. lactis JCM 10602, B. pseudocatenulatum JCM 1200 and B. longum 6:18 (prebiotic score >50%). All strains exhibited extracellular antimicrobial activity (AMA) against four CD strains including the CD NAP1/027. AMA of B. breve 46, B. lactis 8:8 and B. lactis JCM 10602 strains was mainly ascribed to a combined action of organic acids and heat stable, protease sensitive antimicrobial peptides when cells were grown in MRSC broth with glucose and by acids when grown with five different prebiotic-non-digestible oligosaccharides (NDOs). None of C. difficile strains degraded five prebiotic-NDOs. Whole cells of B. breve 46 and B. lactis 8:8 and their supernatants inhibited the growth and toxin production of the CD NAP1/027 strain. 相似文献
225.
226.
Staphylococcus aureus, which mediated binding to heparan sulfate, and also strains of coagulase-negative staphylococci (CNS) adhered in high numbers
to polymers with end-point attached heparin. A characteristic feature of several cell growth factors is strong affinity for
heparin. In the present study, binding of the 125I-labeled heparin-binding growth factors (HBGF), acidic and basic fibroblast growth factor (aFGF, bFGF), and platelet-derived
growth factor (PDGF) by S. aureus and CNS strains was examined. Staphylococcal strains used in this study bind bFGF and PDGF, but not aFGF. The binding of
bFGF and PDGF was time dependent, influenced by pH and ionic strength for S. aureus Cowan 1. Preincubation of staphylococcal cells with unlabeled bFGF enhanced bFGF binding, but heparin, protamine sulfate,
poly-L-lysine, and suramin were potent inhibitors of 125I-bFGF binding to cells of S. aureus Cowan 1. Glycosaminoglycans of comparable size (chondroitin sulfate), other polysulfated polymers (λ-carrageenan, fucoidan),
and some polysulfated polysaccharides (dextran sulfate, pentosan polysulfate) inhibited binding of both GFs to various extents.
The partial inhibition of binding of both GFs after protease and periodate treatments indicates that both proteinaceous and
other carbohydrate moieties participate in the binding. A lysozyme cell surface extract and bacterial lysates of S. aureus Cowan 1 competitively inhibited binding of 125I-bFGF and 125I-PDGF. These results suggest that staphylococci have the ability to bind two of the HBGFs, bFGF and PDGF, but not aFGF, via
more than one cell structure. These binding structures seem to be exposed on the cell surface and deeply anchored in the cytoplasmic
membrane as well. 相似文献
227.
228.
Specific binding of collagen type IV to Streptococcus pyogenes 总被引:5,自引:0,他引:5
Many strains of Streptococcus pyogenes are capable of binding type IV collagen. In the present study, all 50 S. pyogenes strains isolated from patients with acute glomerulonephritis showed high or moderate affinity for radiolabelled type IV collagen. A majority of strains of other sources, such as reference strains of various M-types and strains isolated from patients with pharyngeal infections also bound type IV collagen; however, a number of weak binders or non-binders were found among those. The collagen type IV binding component(s) on S. pyogenes were susceptible to proteinase K digestion, partially sensitive to trypsin but insensitive to pepsin treatment at pH 5.5. According to tests with three M-positive strains and their M-negative derivatives, the binding was not dependent on M-protein. The binding was saturable with time and inhibited by unlabelled type IV collagen. Partially inhibition was found with type II collagen, gelatin and fibrinogen but not with a number of other serum proteins. 相似文献
229.
Infiltration phyto- and protozooplankton assemblages in the annual sea ice of Disko Island, West Greenland, spring 1996 总被引:2,自引:1,他引:1
Kurt R. Buck Torkel G. Nielsen Benni W. Hansen Dorte Gastrup-Hansen Helge A. Thomsen 《Polar Biology》1998,20(6):377-381
During the spring of 1996 we occupied a station on annual sea ice located several kilometers from Disko Island, West Greenland
in water depths greater than 200 m. The goal of this 3-week field season was to characterize sea-ice communities and the underlying
water column prior to, and during, ice break-up. A heavier than usual snow load depressed the sea ice below sea level and
the snow-ice interface became flooded. Some of this flooded region subsequently refroze and the whole process repeated itself
when additional snow accumulated. The infiltration phytoplankton and protozooplankton assemblages that developed in this region
were abundant and diverse. Algal biomass in the infiltration layer was approximately an order of magnitude greater than in
the underlying water column but an order of magnitude less than in the well-developed bottom ice community. The infiltration
autotrophic assemblage resembled the bottom-ice assemblage while the protozooplankton assemblage was more similar to the water
column assemblage.
Received: 13 February 1998 / Accepted: 30 May 1998 相似文献
230.
Daniel P. Vang Gregory T. Wurz Stephen M. Griffey Chiao-Jung Kao Audrey M. Gutierrez Gregory K. Hanson Michael Wolf Michael W. DeGregorio 《Journal of visualized experiments : JoVE》2013,(80)
A preclinical model of invasive bladder cancer was developed in human mucin 1 (MUC1) transgenic (MUC1.Tg) mice for the purpose of evaluating immunotherapy and/or cytotoxic chemotherapy. To induce bladder cancer, C57BL/6 mice (MUC1.Tg and wild type) were treated orally with the carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine (OH-BBN) at 3.0 mg/day, 5 days/week for 12 weeks. To assess the effects of OH-BBN on serum cytokine profile during tumor development, whole blood was collected via submandibular bleeds prior to treatment and every four weeks. In addition, a MUC1-targeted peptide vaccine and placebo were administered to groups of mice weekly for eight weeks. Multiplex fluorometric microbead immunoanalyses of serum cytokines during tumor development and following vaccination were performed. At termination, interferon gamma (IFN-γ)/interleukin-4 (IL-4) ELISpot analysis for MUC1 specific T-cell immune response and histopathological evaluations of tumor type and grade were performed. The results showed that: (1) the incidence of bladder cancer in both MUC1.Tg and wild type mice was 67%; (2) transitional cell carcinomas (TCC) developed at a 2:1 ratio compared to squamous cell carcinomas (SCC); (3) inflammatory cytokines increased with time during tumor development; and (4) administration of the peptide vaccine induces a Th1-polarized serum cytokine profile and a MUC1 specific T-cell response. All tumors in MUC1.Tg mice were positive for MUC1 expression, and half of all tumors in MUC1.Tg and wild type mice were invasive. In conclusion, using a team approach through the coordination of the efforts of pharmacologists, immunologists, pathologists and molecular biologists, we have developed an immune intact transgenic mouse model of bladder cancer that expresses hMUC1. 相似文献