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81.
Fletcher L 《Nature biotechnology》2002,20(9):857-858
82.
Mutational Analysis of the N-Linked Glycans on Autographa californica Nucleopolyhedrovirus gp64 总被引:2,自引:0,他引:2
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Donald L. Jarvis Liz Wills Gloria Burow Dwight A. Bohlmeyer 《Journal of virology》1998,72(12):9459-9469
gp64 is the major envelope glycoprotein in the budded form of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). gp64 is essential for AcMNPV infection, as it mediates penetration of budded virus into host cells via the endocytic pathway. In this study, we used site-directed mutagenesis to map the positions of the N-linked glycans on AcMNPV gp64, characterize their structures, and evaluate their influence on gp64 function. We found that four of the five consensus N-glycosylation sites in gp64 are used, and we mapped the positions of those sites to amino acids 198, 355, 385, and 426 in the polypeptide chain. Endoglycosidase H sensitivity assays showed that N-linked glycans located at different positions are processed to various degrees. Lectin blotting analyses showed that each N-linked glycan on gp64 contains α-linked mannose, all but one contains α-linked fucose, and none contains detectable β-linked galactose or α2,6-linked sialic acid. The amounts of infectious progeny produced by AcMNPV mutants lacking one, two, or three N-linked glycans on gp64 were about 10- to 100-fold lower than wild-type levels. This reduction did not correlate with reductions in the expression, transport, or inherent fusogenic activity of the mutant gp64s or in the gp64 content of mutant budded virus particles. However, all of the mutant viruses bound more slowly than the wild type. Therefore, elimination of one or more N-glycosylation sites in AcMNPV gp64 impairs binding of budded virus to the cell, which explains why viruses containing these mutant forms of gp64 produce less infectious progeny. 相似文献
83.
Díaz-Vázquez LM García O Velázquez Z Marrero I Rosario O 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2005,825(1):11-20
Methodology using MAE/SPME/GC-MS is being pursued for the analysis of organic pollutants in sebum. The microwave-assisted extraction (MAE) of standards of semi volatile organic pollutants from sebum was optimized. All compounds were extracted from sebum with recoveries analyzed by GC/MS ranging from 94% to 100% under the optimum MAE conditions: 10mL acetone-hexane (2:1), 60 degrees C, and 10 min microwave heating. To improve the detection limits a SPME procedure was optimized. Linearity ranged from 0.70 ppb to 25 ppb. R.S.D. were in the range of 1-23% for the SPME step. Preliminary real samples were analyzed and a range of compounds was detected. The optimized MAE/SPME/GC-MS methodology promises to be useful for different applications. 相似文献
84.
The scl +18/19 stem cell enhancer is not required for hematopoiesis: identification of a 5' bifunctional hematopoietic-endothelial enhancer bound by Fli-1 and Elf-1
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85.
86.
Turnbull LA Manley L Rees M 《Proceedings. Biological sciences / The Royal Society》2005,272(1570):1357-1364
Pioneer species are fast-growing, short-lived gap exploiters. They are prime candidates for neutral dynamics because they contain ecologically similar species whose low adult density is likely to cause widespread recruitment limitation, which slows competitive dynamics. However, many pioneer guilds appear to be differentiated according to seed size. In this paper, we compare predictions from a neutral model of community structure with three niche-based models in which trade-offs involving seed size form the basis of niche differentiation. We test these predictions using sowing experiments with a guild of seven pioneer species from chalk grassland. We find strong evidence for niche structure based on seed size: specifically large-seeded species produce fewer seeds but have a greater chance of establishing on a per-seed basis. Their advantage in establishment arises because there are more microsites suitable for their germination and early establishment and not directly through competition with other seedlings. In fact, seedling densities of all species were equally suppressed by the addition of competitors' seeds. By the adult stage, despite using very high sowing densities, there were no detectable effects of interspecific competition on any species. The lack of interspecific effects indicates that niche differentiation, rather than neutrality, prevails. 相似文献
87.
Mark Brennan-Ing Liz Seidel Leslie Rodgers Jerome Ernst Doug Wirth Daniel Tietz Antonio Morretti Stephen E. Karpiak 《PloS one》2016,11(2)
In 1990, New York State instituted Comprehensive Medicaid Case Management, also known as Target Case Management (TCM), for people dealing with multiple comorbid conditions, including HIV. The goal of TCM is to assist clients in navigating the health care system to increase care engagement and treatment adherence for individuals with complex needs. HIV-positive individuals engaged in care are more likely to be virally suppressed, improving clinical outcomes and decreasing chances of HIV transmission. The purpose of this study was to understand the impact of TCM management on outcomes for people with HIV. Data were obtained from Amida Care, which operates not-for-profit managed care Medicaid and Medicare Special Needs Plans (SNPs) for HIV clients. Changes in clinical, cost, as well as medical and pharmacy utilization data among TCM clients were examined between January 2011 through September 2012 from the start of case management enrollment through the end of the study period (i.e., up to 6 months after disenrollment). Additionally, CD4 counts were compared between Amida Care TCM clients and non-TCM clients. Notable findings include increased CD4 counts for TCM clients over the one-year study period, achieving parity with non-TCM clients (i.e., Mean CD4 count > 500). When looking exclusively at TCM clients, there were increases in medication costs over time, which were concomitant with increased care engagement. Current findings demonstrate that TCM is able to achieve its goals of improving care engagement and treatment adherence. Subsequent policy changes resulting from the Affordable Care Act and the New York State Medicaid Redesign have made the Health Home the administrator of TCM services. Government entities charged with securing and managing TCM and care coordination for people with HIV should provide thoughtful and reasonable guidance and oversight in order to maintain optimal clinical outcomes for TCM clients and reduce the transmission of HIV. 相似文献
88.
Andrew M. Goetze Liz Fayer Jennifer Bouska Dirk Bornemeier George W. Carter 《Prostaglandins & other lipid mediators》1985,29(5):689-701
5-Lipoxygenase (5-lipox) has been purified to homogeneity from the 20,000 xg supernatant of sonicated rat basophilic leukemia (RBL-1) cells using a 4-step procedure. Purification was achieved primarily through the use of anion-exchange HPLC on two different media. Using the supernatant from 1 × 10 9 cells, approximately 33 μg of the enzyme can be routinely isolated with an estimated net yield of 5–10%. Purified 5-lipox consists of a single Mr 73,000 band on SDS gels (reduced or unreduced). When the purified enzyme was incubated with radiolabeled arachidonic acid and products analyzed by both straight phase and reversed phase HPLC, 5-hydroperoxyeicosate-traenoic acid (5-HPETE) was the only enzymatic product detected. The purified enzyme exhibits the same characteristic lag phase and premature cessation of reaction as does the 5-lipox activity seen in crude cell homogenates. 相似文献
89.
Ruth Chan Vincent Wai-Sun Wong Winnie Chiu-Wing Chu Grace Lai-Hung Wong Liz Sin Li Jason Leung Angel Mei-Ling Chim David Ka-Wai Yeung Mandy Man-Mei Sea Jean Woo Francis Ka-Leung Chan Henry Lik-Yuen Chan 《PloS one》2015,10(4)
Nonalcoholic fatty liver disease (NAFLD) has been associated with reduced growth hormone levels and signaling. Such hormonal changes also occur in metabolic acidosis. Since mild metabolic acidosis can be diet induced, diet-induced acid load may constitute a nutritional factor with possible influence on NAFLD development. This study explored whether a higher diet-induced acid load is associated with an increased likelihood of NAFLD. Apparently healthy Chinese adults (330 male, 463 female) aged 19-72 years were recruited through population screening between 2008 and 2010 in a cross-sectional population-based study in Hong Kong. Estimated net endogenous acid production (NEAP) was calculated using Frassetto’s method and potential renal acid load (PRAL) was calculated using Remer’s method based on dietary data from a food frequency questionnaire. NAFLD was defined as intrahepatic triglyceride content at >5% by proton-magnetic resonance spectroscopy. Possible advanced fibrosis was defined as liver stiffness at >7.9 kPa by transient elastography. Multivariate logistic regression models were used to examine the association between each measure of dietary acid load and prevalent NAFLD or possible advanced fibrosis with adjustment for potential anthropometric and lifestyle factors. 220 subjects (27.7%) were diagnosed with NAFLD. Estimated NEAP was positively associated with the likelihood of having NAFLD after adjustment for age, sex, body mass index, current drinker status and the presence of metabolic syndrome [OR (95% CI) = 1.25 (1.02-1.52), p = 0.022]. The association was slightly attenuated but remained significant when the model was further adjusted for other dietary variables. No association between PRAL and NAFLD prevalence was observed. Both estimated NEAP and PRAL were not associated with the presence of possible advance fibrosis. Our findings suggest that there may be a modest association between diet-induced acid load and NAFLD. More studies are needed to ascertain the link between diet-induced acid load and NAFLD and to investigate the underlying mechanisms. 相似文献
90.