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排序方式: 共有260条查询结果,搜索用时 31 毫秒
181.
Wolfgang Link Julen Oyarzabal Beatriz G. Serelde Maria Isabel Albarran Obdulia Rabal Antonio Cebri�� Patricia Alfonso Jesus Fominaya Oliver Renner Sandra Peregrina David Soil��n Pl��cido A. Ceballos Ana-Isabel Hern��ndez Milagros Lorenzo Paolo Pevarello Teresa G. Granda Guido Kurz Amancio Carnero James R. Bischoff 《The Journal of biological chemistry》2009,284(41):28392-28400
182.
Background
For accurate and reliable gene expression analysis, normalization of gene expression data against reference genes is essential. In most studies on ticks where (semi-)quantitative RT-PCR is employed, normalization occurs with a single reference gene, usually β-actin, without validation of its presumed expression stability. The first goal of this study was to evaluate the expression stability of commonly used reference genes in Rhipicephalus appendiculatus and Rhipicephalus (Boophilus) microplus ticks. To demonstrate the usefulness of these results, an unresolved issue in tick vaccine development was examined. Commercial vaccines against R. microplus were developed based on the recombinant antigen Bm86, but despite a high degree of sequence homology, these vaccines are not effective against R. appendiculatus. In fact, Bm86-based vaccines give better protection against some tick species with lower Bm86 sequence homology. One possible explanation is the variation in Bm86 expression levels between R. microplus and R. appendiculatus. The most stable reference genes were therefore used for normalization of the Bm86 expression profile in all life stages of both species to examine whether antigen abundance plays a role in Bm86 vaccine susceptibility. 相似文献183.
Ana Villa Isabel Liste Elise T. Courtois Milagros Ramos Bengt Juliusson Alberto Martínez-Serrano 《Experimental cell research》2009,315(11):1860-1773
Neural stem cells (NSCs) are powerful research tools for the design and discovery of new approaches to cell therapy in neurodegenerative diseases like Parkinson's disease. Several epigenetic and genetic strategies have been tested for long-term maintenance and expansion of these cells in vitro.Here we report the generation of a new stable cell line of human neural stem cells derived from ventral mesencephalon (hVM1) based on v-myc immortalization.The cells expressed neural stem cell and radial glia markers like nestin, vimentin and 3CB2 under proliferation conditions. After withdrawal of growth factors, proliferation and expression of v-myc were dramatically reduced and the cells differentiated into astrocytes, oligodendrocytes and neurons. hVM1 cells yield a large number of dopaminergic neurons (about 12% of total cells are TH+) after differentiation, which also produce dopamine. In addition to proneural genes (NGN2, MASH1), differentiated cells show expression of several genuine mesencephalic dopaminergic markers such as: LMX1A, LMX1B, GIRK2, ADH2, NURR1, PITX3, VMAT2 and DAT, indicating that they retain their regional identity.Our data indicate that this cell line and its clonal derivatives may constitute good candidates for the study of development and physiology of human dopaminergic neurons in vitro, and to develop tools for Parkinson's disease cell replacement preclinical research and drug testing. 相似文献
184.
185.
Inmaculada Yruela Sonia Arilla-Luna Milagros Medina Bruno Contreras-Moreira 《BMC evolutionary biology》2010,10(1):311
Background
Flavin adenine dinucleotide synthetases (FADSs) - a group of bifunctional enzymes that carry out the dual functions of riboflavin phosphorylation to produce flavin mononucleotide (FMN) and its subsequent adenylation to generate FAD in most prokaryotes - were studied in plants in terms of sequence, structure and evolutionary history. 相似文献186.
Karl Kreij Carl-Fredrik Mandenius João J. Clemente António Eduardo Cunha Sandra M. S. Monteiro Manuel J. T. Carrondo Friedemann Hesse Maria Milagros Bassani de los Molinas Roland Wagner Otto-Wilhelm Merten Cécile Gény- Fiamma Wolfgang Leger Herbert Wiesinger-Mayr Dethard Müller Hermann Katinger Per Mårtensson Thomas Bachinger Jan Mitrovics 《Cytotechnology》2005,48(1-3):41-58
An electronic nose (EN) device was used to detect microbial and viral contaminations in a variety of animal cell culture systems.
The emission of volatile components from the cultures accumulated in the bioreactor headspace, was sampled and subsequently
analysed by the EN device. The EN, which was equipped with an array of 17 chemical gas sensors of varying selectivity towards
the sampled volatile molecules, generated response patterns of up to 85 computed signals. Each 15 or 20 min a new gas sample
was taken generating a new response pattern. A software evaluation tool visualised the data mainly by using principal component
analysis. The EN was first used to detect microbial contaminations in a Chinese hamster ovary (CHO) cell line producing a
recombinant human macrophage colony stimulating factor (rhM-CSF). The CHO cell culture was contaminated by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida utilis which all were detected. The response patterns from the CHO cell culture were compared with monoculture references of the
microorganisms. Second, contaminations were studied in an Sf-9 insect cell culture producing another recombinant protein (VP2
protein). Contaminants were detected from E. coli, a filamentous fungus and a baculovirus. Third, contamination of a human cell line, HEK-293, infected with E. coli exhibited comparable results. Fourth, bacterial contaminations could also be detected in cultures of a MLV vector producer
cell line. Based on the overall experiences in this study it is concluded that the EN method has in a number of cases the
potential to be developed into a useful on-line contamination alarm in order to support safety and economical operation for
industrial cultivation. 相似文献
187.
Goñi G Serrano A Frago S Hervás M Peregrina JR De la Rosa MA Gómez-Moreno C Navarro JA Medina M 《Biochemistry》2008,47(4):1207-1217
Three surface hydrophobic residues located at the Anabaena flavodoxin (Fld) putative complex interface with its redox partners were replaced by site-directed mutagenesis. The effects of these replacements on Fld interaction with both its physiological electron donor, photosystem I (PSI), and its electron acceptor, ferredoxin-NADP+ reductase (FNR), were analyzed. Trp57, Ile59, and Ile92 contributed to the optimal orientation and tightening of the FNR:Fld and PSI:Fld complexes. However, these side chains did not appear to be involved in crucial specific interactions, but rather contributed to the obtainment of the optimal orientation and distance of the redox centers required for efficient electron transfer. This supports the idea that the interaction of Fld with its partners is less specific than that of ferredoxin and that more than one orientation is efficient for electron transfer in these transient complexes. Additionally, for some of the analyzed processes, WT Fld seems not to be the most optimized molecular species. Therefore, subtle changes at the isoalloxazine environment not only influence the Fld binding abilities, but also modulate the electron exchange processes by producing different orientations and distances between the redox centers. Finally, the weaker apoflavodoxin interaction with FNR suggests that the solvent-accessible region of FMN plays a role either in complex formation with FNR or in providing the adequate conformation of the FNR binding region in Fld. 相似文献
188.
Fernández EG Cordero S Benítez M Perdomo I Morón Y Morales AE Arce MG Cuesta E Lugones J Fernández M Gil A Valdés R Fernández M 《AAPS PharmSciTech》2008,9(2):620-627
The purpose of this paper was to develop a statistical methodology to optimize tablet manufacturing considering drug chemical
and physical properties applying a crossed experimental design. The assessed model drug was dried ferrous sulphate and the
variables were the hardness and the relative proportions of three excipients, binder, filler and disintegrant. Granule properties
were modeled as a function of excipient proportions and tablet parameters were defined by the excipient proportion and hardness.
The desirability function was applied to achieve optimal values for excipient proportions and hardness. In conclusion, crossed
experimental design using hardness as the only process variable is an efficient strategy to quickly determine the optimal
design process for tablet manufacturing. This method can be applied for any tablet manufacturing method. 相似文献
189.
Liu X Shi Y Guan R Donawho C Luo Y Palma J Zhu GD Johnson EF Rodriguez LE Ghoreishi-Haack N Jarvis K Hradil VP Colon-Lopez M Cox BF Klinghofer V Penning T Rosenberg SH Frost D Giranda VL Luo Y 《Molecular cancer research : MCR》2008,6(10):1621-1629
Poly(ADP-ribose) polymerase (PARP) senses DNA breaks and facilitates DNA repair via the polyADP-ribosylation of various DNA binding and repair proteins. We explored the mechanism of potentiation of temozolomide cytotoxicity by the PARP inhibitor ABT-888. We showed that cells treated with temozolomide need to be exposed to ABT-888 for at least 17 to 24 hours to achieve maximal cytotoxicity. The extent of cytotoxicity correlates with the level of double-stranded DNA breaks as indicated by gammaH2AX levels. In synchronized cells, damaging DNA with temozolomide in the presence of ABT-888 during the S phase generated high levels of double-stranded breaks, presumably because the single-stranded DNA breaks resulting from the cleavage of the methylated nucleotides were converted into double-stranded breaks through DNA replication. As a result, treatment of temozolomide and ABT-888 during the S phase leads to higher levels of cytotoxicity. ABT-888 inhibits poly(ADP-ribose) formation in vivo and enhances tumor growth inhibition by temozolomide in multiple models. ABT-888 is well tolerated in animal models. ABT-888 is currently in clinical trials in combination with temozolomide. 相似文献
190.
A regulatory cascade involving retinoic acid, Cbfa1, and matrix metalloproteinases is coupled to the development of a process of perichondrial invasion and osteogenic differentiation during bone formation 总被引:4,自引:0,他引:4 下载免费PDF全文