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排序方式: 共有263条查询结果,搜索用时 15 毫秒
91.
92.
Nasim Mansoori Jaap Timmers Thierry Desprez Claire L. A. Kamei Dianka C. T. Dees Jean-Paul Vincken Richard G. F. Visser Herman H?fte Samantha Vernhettes Luisa M. Trindade 《PloS one》2014,9(11)
Cellulose is synthesized by the so called rosette protein complex and the catalytic subunits of this complex are the cellulose synthases (CESAs). It is thought that the rosette complexes in the primary and secondary cell walls each contains at least three different non-redundant cellulose synthases. In addition to the CESA proteins, cellulose biosynthesis almost certainly requires the action of other proteins, although few have been identified and little is known about the biochemical role of those that have been identified. One of these proteins is KORRIGAN (KOR1). Mutant analysis of this protein in Arabidopsis thaliana showed altered cellulose content in both the primary and secondary cell wall. KOR1 is thought to be required for cellulose synthesis acting as a cellulase at the plasma membrane–cell wall interface. KOR1 has recently been shown to interact with the primary cellulose synthase rosette complex however direct interaction with that of the secondary cell wall has never been demonstrated. Using various methods, both in vitro and in planta, it was shown that KOR1 interacts specifically with only two of the secondary CESA proteins. The KOR1 protein domain(s) involved in the interaction with the CESA proteins were also identified by analyzing the interaction of truncated forms of KOR1 with CESA proteins. The KOR1 transmembrane domain has shown to be required for the interaction between KOR1 and the different CESAs, as well as for higher oligomer formation of KOR1. 相似文献
93.
S. Tereso C. M. Miguel M. Mascarenhas A. Roque H. Trindade J. Maroco M. M. Oliveira 《Biologia Plantarum》2008,52(3):437-444
A highly reproducible system was developed for efficient rooting of cultivars Boa Casta (BC) and Peneda and a BC seedling-derived
clone (BC VII) of almond (Prunus dulcis Mill.). Twenty-four accessions derived from the clone BC VII and subjected to various in vitro culture treatments were screened. The long induction pre-treatment (LIP, 5 d), the brief induction pre-treatment (BIP, 16
h) and the hormonal shock by short dipping in hormone solution (1 min), were tested. BIP was the only that allowed rooting
of cultivars. In BC VII, it induced high rooting frequencies (47–100 %) when using a solution of 0.4 mM indole-3-butyric acid
solidified with 2 g dm−3 gellam gum for 16-h. The response to the auxin type was variable depending on the cultivar and the root induction pre-treatment
used. Root number was significantly different between the two cultivars and BC VII. Root length was significantly higher when
using 0.005 mM IBA in LIP but this concentration induced apical necrosis. The improved acclimatization procedure for up to
4 weeks increased the survival to 45 %. The initiation and development of adventitious roots were proved to be asynchronous. 相似文献
94.
Trindade ES Bouças RI Rocha HA Dominato JA Paredes-Gamero EJ Franco CR Oliver C Jamur MC Dietrich CP Nader HB 《Journal of cellular physiology》2008,217(2):360-366
In vitro, heparin and antithrombotic drugs specifically stimulate the synthesis of an antithrombotic heparan sulfate proteoglycan (HSPG) produced by endothelial cells. The putative heparin binding site(s) that may be related to this phenomenon were investigated. In the preceding article, using various heparin probes, it was shown that the heparin does not bind to the endothelial cell surface, but only to the extracellular matrix. The present study demonstrated that, when the cells were exposed to heparin at 37 degrees C, the heparin was internalized and with time was localized in lysosomes. However, endocytosis of heparin was not required for the stimulation of HSPG synthesis. The requirement for heparin degradation in the stimulus of HSPG synthesis was also investigated. When the cells were incubated with chloroquine, a lysosomotropic amine that raises the lysosomal pH thus inhibiting enzymatic degradation of internalized compounds, stimulation of HSPG synthesis was still observed. These combined results indicate that neither internalization nor degradation of heparin is required for stimulation of HSPG synthesis, and suggests that its binding to the extracellular matrix could be responsible for this effect. 相似文献
95.
96.
Videira PA Amado IF Crespo HJ Algueró MC Dall'Olio F Cabral MG Trindade H 《Glycoconjugate journal》2008,25(3):259-268
Several glycoconjugates are involved in the immune response. Sialic acid is frequently the glycan terminal sugar and it may
modulate immune interactions. Dendritic cells (DCs) are antigen-presenting cells with high endocytic capacity and a central
role in immune regulation. On this basis, DCs derived from monocytes (mo-DC) are utilised in immunotherapy, though many features
are ignored and their use is still limited. We analyzed the surface sialylated glycans expressed during human mo-DC generation.
This was monitored by lectin binding and analysis of sialyltransferases (ST) at the mRNA level and by specific enzymatic assays.
We showed that α2-3-sialylated O-glycans and α2-6- and α2-3-sialylated N-glycans are present in monocytes and their expression increases during mo-DC differentiation. Three main ST genes are committed
with this rearrangement: ST6Gal1 is specifically involved in the augmented α2-6-sialylated N-glycans; ST3Gal1 contributes for the α2-3-sialylation of O-glycans, particularly T antigens; and ST3Gal4 may contribute for the increased α2-3-sialylated N-glycans. Upon mo-DC maturation, ST6Gal1 and ST3Gal4 are downregulated and ST3Gal1 is altered in a stimulus-dependent manner.
We also observed that removing surface sialic acid of immature mo-DC by neuraminidase significantly decreased its endocytic
capacity, while it increased in monocytes. Our results indicate the STs expression modulates the increased expression of surface
sialylated structures during mo-DC generation, which is probably related with changes in cell mechanisms. The ST downregulation
after mo-DC maturation probably results in a decreased sialylation or sialylated glycoconjugates involved in the endocytosis,
contributing to the downregulation of one or more antigen-uptake mechanisms specific of mo-DC. 相似文献
97.
98.
Helena Trindade Monya M. CostaB. Lima A. Sofia Luis G. PedroAna C. Figueiredo José G. Barroso 《Biochemical Systematics and Ecology》2008
Thirty-one individuals from Thymus caespititius were collected on the islands of Pico, São Jorge and Terceira (Azores) and the volatiles were isolated by distillation–extraction and analyzed by GC and GC–MS. The same plants were analyzed by RAPD using 17 arbitrary primers that generated 187 scorable polymorphic bands. The volatile composition of the individuals was in accordance with previous results obtained from the populations’ analysis, confirming that the chemical polymorphism was in some cases more evident among different plants from the same island than among those collected on different islands. RAPDs analyses using the same individuals did not show identical clustering as with the volatile oil profiles and no straight correlation among collection site, chemical analysis and molecular assessments could be found, suggesting that other molecular tools should be explored in order to fully understand the influence of both environmental and genetic factors on volatiles composition. 相似文献
99.
The bacterial strain Bacillus cereus is closely related to Bacillus thuringiensis, although any genetic relationship between the two strains is still in debate. Using rep-PCR genomic fingerprinting, we established the genetic relationships between Brazilian sympatric populations of B. cereus and B. thuringiensis simultaneously collected from two geographically separate sites. We observed the formation of both B. thuringiensis and B. cereus clusters, as well as strains of B. cereus that are more closely related to B. thuringiensis than to other B. cereus strains. In addition, lower genetic variability was observed among B. thuringiensis clusters compared to B. cereus clusters, indicating that either the two species should be categorized as separate or that B. thuringiensis may represent a clone from a B. cereus background. 相似文献
100.