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61.
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Ana I. Calejo Eleazar Rodriguez Virgília S. Silva Jernej Jorgačevski Matjaž Stenovec Marko Kreft Conceição Santos Robert Zorec Paula P. Gonçalves 《Cell biology and toxicology》2010,26(4):341-353
Prolonged exposure to aluminium may impact health. Aluminium’s deleterious effects are mostly attributed to its selective
accumulation in particular organs and cell types. Occupational exposure to aluminium is allied with a reduced level of serum
prolactin, a stress peptide hormone mainly synthesised and secreted by the anterior pituitary lactotrophs. Our aim was to
study the effect of aluminium on the viability of rat lactotrophs in primary suspension cultures where multicellular aggregates
tend to form, comprising approximately two thirds of the total cell population as confirmed by confocal microscopy. Flow cytometric
light scattering of calcein acetoxymethyl ester and ethidium homodimer-1 labelled cells was used to define subpopulations
of live and dead cells in heterogeneous suspensions comprised of single cells and multicellular aggregates of distinct size.
Concentration-dependent effects of AlCl3 were observed on aggregate size and cell survival. After 24-h exposure to 3 mM AlCl3, viability of single cells declined from 5% to 3%, while in multicellular aggregates, viability declined from 23% to 20%.
The proportion of single cells increased from 30% to 42% within the same concentration range, while in large aggregates, the
proportion remained approximately constant representing 35% of the cell suspension. In large aggregates, cell viability (75%)
remained unaltered after exposure to AlCl3 concentrations up to 300 μM, while in single cells, viability was halved at 30 μM. In conclusion, our finding indicates that
prolonged exposure to aluminium may lead to significant loss of pituitary cells. 相似文献
63.
Potato cysteine proteinase inhibitor gene family: molecular cloning,characterisation and immunocytochemical localisation studies 总被引:1,自引:0,他引:1
Gruden Kristina Štrukelj Borut Ravnikar Maja Poljšak-Prijatelj Mateja Mavrič Irena Brzin Jože Pungerčar Jože Kregar Igor 《Plant molecular biology》1997,34(2):317-323
Potato cysteine proteinase inhibitors (PCPIs) represent a distinct group of proteins as they show no homology to any other known cysteine proteinase inhibitor superfamilies, but they all belong to the Kunitz-type soybean trypsin inhibitor family. cDNA clones for five PCPIs have been isolated and sequenced. Amino acid substitutions occurring in the limited regions forming loops on the surface of these proteins suggest a further classification of PCPIs into three subgroups. Accumulation of PCPI was observed in vacuoles of stems after treatment with jasmonic acid (JA) using immunocytochemical localisation, implying that these inhibitors are part of a potato defence mechanism against insects and pathogens. Genomic DNA analysis show that PCPIs form a multigene family and suggest that their genes do not possess any introns. 相似文献
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66.
Production, purification and characterization of hemolysins from Listeria ivanovii and Listeria monocytogenes Sv4b 总被引:12,自引:0,他引:12
Jürgen Kreft Dorothee Funke Albert Haas Friedrich Lottspeich Werner Goebel 《FEMS microbiology letters》1989,57(2):197-202
In culture supernatants of both Listeria ivanovii and Listeria monocytogenes Sv4b, for the first time a hemolysin of molecular weight 58 kDa was identified, which had all the characteristics of an SH-activated cytolysin, and which was therefore identified as listeriolysin O (LLO). In the case of L. ivanovii a second major supernatant protein of molecular weight 24 kDa co-purified with LLO. However, the function of this protein has to be determined. In culture supernatants of L. ivanovii a sphingomyelinase and a lecithinase activity could be detected, both enzymatic activities together contributing to the pronounced hemolysis caused by L. ivanovii. The N-terminal amino acid sequences of LLO and the 24 kDa from L. ivanovii are shown. 相似文献
67.
Jürgen Kreft 《FEMS microbiology letters》1995,132(1-2):181-181
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When the urothelial barrier, i.e., the blood−urine barrier, is injured, rapid resealing of the injury is crucial for the normal
functioning of the organism. In order to investigate the mechanisms required for rapid resealing of the barrier, we established
in vitro models of hyperplastic and normoplastic urothelia. We found that hyperplastic urothelia achieve significantly higher
transepithelial resistance (TER) than normoplastic urothelia. However, the expression of cell junctional (claudin-8, occludin,
E-cadherin) and differentiation-related proteins (cytokeratin 20 and uroplakins) is weaker in hyperplastic urothelia. Further
investigation of cell differentiation status at the ultrastructural level confirmed that superficial urothelial cells (UCs)
in hyperplastic urothelial models achieve a lower differentiation stage than superficial UCs in normoplastic urothelial models.
With the establishment of such in vitro models and the aid of TER measurements, flow cytometry, molecular and ultrastructural
analysis, we here provide unequivocal evidence that the specific cell-cycle distribution and, consequently, the number of
cell layers have a significant influence on the barrier function of urothelia. We demonstrate the importance of hyperplasia
for the rapid restoration of the urothelial barrier and the maintenance of high TER until the UCs reach a highly differentiated
stage and restoration of the urothelial barrier after injury is complete. The information that this approach provides is unique
and we expect that further exploitation of hyperplastic and normoplastic urothelial models in future studies may advance our
understanding of blood−urine barrier development and functionality. 相似文献
70.
Human leucine-rich repeat kinase 1 (LRRK1) is a multi-domain protein of unknown function belonging to the ROCO family of complex proteins. Here, we report the molecular characterization of human LRRK1 and show, for the first time, that LRRK1 is both a functional protein kinase and a GDP/GTP-binding protein. Binding of GTP to LRRK1 is specific, requires the GTPase-like Roc domain, and leads to a stimulation of LRRK1 kinase activity. LRRK1 is the first example of a GTP-regulated protein kinase harboring both the kinase effector domain and the GTP-binding regulatory domain. Hence, we propose a model in which LRRK1 cycles between a GTP-bound active and a GDP-bound inactive state. Moreover, we mutated LRRK1 to mimic mutations previously identified in LRRK2/dardarin, the only human paralogue of LRRK1, that have been linked to autosomal-dominant parkinsonism. We demonstrate that three of four mutations analyzed significantly downregulate LRRK1 kinase activity. Ultimately, the results presented for LRRK1 may contribute to the elucidation of LRRK2's role in the pathogenesis of Parkinson's disease. 相似文献