全文获取类型
收费全文 | 304篇 |
免费 | 14篇 |
出版年
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2013年 | 7篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 19篇 |
2006年 | 20篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1959年 | 4篇 |
1953年 | 2篇 |
1952年 | 2篇 |
1951年 | 2篇 |
1949年 | 3篇 |
1939年 | 2篇 |
1937年 | 2篇 |
1936年 | 3篇 |
排序方式: 共有318条查询结果,搜索用时 31 毫秒
131.
Heinz Tiedemann Hildegard Tiedemann Jochen Born U. Kocher-Becker 《Development genes and evolution》1969,163(4):316-324
Zusammenfassung Rohfraktionen aus 9 Tage alten Hühnerembryonen, die neuralisierenden und mesodermalisierenden Induktionsfaktor enthielten, sowie angereicherter mesodermalisierender Faktor wurden mit Thioglykolsäure sowie mit 2-Mercaptoäthanol behandelt. Die Fraktionen wurden an Gastrulen vonTriturus alpestris oderAmbystoma nach der Implantationsmethode getestet. Der mesodermalisierende Faktor wird inaktiviert. Die Aktivität des neuralisierenden Faktors bleibt dagegen erhalten.
Der Deutschen Forschungsgemeinschaft danken wir für Unterstützung der Arbeit. 相似文献
Action of sulfhydryl compounds on embryonic inducing factors
Summary Crude extracts from 9 days old chicken embryos containing neuralizing and mesodermalizing inducing factors as well as purified mesodermalizing factor were incubated with thioglycolic acid and with 2-Mercaptoethanol. The fractions were tested by implanting into early gastrulae ofTriturus orAmbystoma. The mesodermalizing factor is inactivated whereas the neuralizing factor does not lose its activity.
Der Deutschen Forschungsgemeinschaft danken wir für Unterstützung der Arbeit. 相似文献
132.
Hildegard M. Schuller 《Mutation research》1997,380(1-2)
This review is a critical appraisal of our current knowledge on nasal cavity carcinogenesis by nitrosamines. The pathology and pathogenesis of nitrosamine-induced tumors in the nasal cavity of rodents is summarized while controversies on the underlying molecular mechanisms are discussed in more detail. Investigations on the distribution of metabolically competent cell types, the cellular site(s) of nitrosamine metabolism, as well as reports on the cellular distribution and persistence of DNA-adducts strongly suggest that DNA-adducts formed from reactive metabolites are not immediately responsible for the genesis of nasal cavity tumors. A preexisting high proliferative ability has also been suggested as a factor rendering certain cell types more susceptible to the carcinogenic actions of nitrosamines in the nasal cavity. However, this hypothesis has been clearly rejected by more recent investigations. Recent studies have shown that nitrosamines can stimulate the secretion of growth factors via interaction with neurotransmitter receptors in the lungs and that this molecular mechanism is an important factor in determining the histological phenotype of the developing lung tumors. In light of the fact that secretory cells are the main sites of DNA-adduct accumulation and toxic lesions in the nasal cavities of nitrosamine treated rodents, it is suggested that similar mechanisms may mediate the genesis of nitrosamine-induced nasal cavity tumors. 相似文献
133.
Normal rat kidney cells, non-productively infected with the anaemia-inducing variant of Friend spleen focus-forming virus (F-SFFVA), were metabolically labelled with [2-3H]mannose. The primary translation product of the viral envelope gene (env), representing a glycoprotein with an apparent molecularM
r of 55 000 (gp55), was isolated from cell lysates by immunoaffinity chromatography and purified by preparative SDS/PAGE. Radiolabelled oligosaccharides, released from tryptic glycopeptides by treatment with endo--N-acetylglucosaminidase H, were characterized chromatographically, by enzymic digestion and by acetolysis. The results revealed that F-SFFVA gp55 obtained from this source carried predominantly oligomannose type sugar chains with five to nine mannoses. As a characteristic feature, glycans with seven to nine mannoses contained, in part, an additional glucose residue. Although the amount of glucosylated species found was higher in F-SFFVA gp55 (about 25% of total endo-H-sensitive oligosaccharides) than in gp55 of the corresponding polycythaemia-inducing variant (F-SFFVP, 16.3%), the overall glycosylation pattern of the F-SFFVA
env product closely resembled that of F-SFFVP gp55 [Strubeet al. (1988)J Biol Chem
263:3762–71]. Hence, our results demonstrate that the different intracellular processing and transport of the primary F-SFFVA
env product cannot be attributed to aberrant trimming of its oligomannose type glycans.Abbreviations endo H
endo--N-acetylglucosaminidase H fromStreptomyces griseus
-
env
envelope gene
- Env protein
translation product ofenv
- F-SFFV
Friend spleen focus-forming virus
- F-SFFVA
anaemia-inducing variant of F-SFFV
- F-SFFVP
polycythaemia-inducing variant of F-SFFV
- Hex
hexose
- NRK
normal rat kidney
- PNGase F
peptide-N
4-(N-acetyl--glucosaminyl)asparagine amidase F fromFlavobacterium meningosepticum 相似文献
134.
Günther Bretzel Jutta Janeczek Jochen Born Manorama John Heinz Tiedemann Hildegard Tiedemann 《Development genes and evolution》1986,195(2):117-122
Summary Plasma membranes were isolated in high yield from Xenopus gastrulae by repeated sedimentation in discontinuous sucrose gradients. Most of the yolk was separated by lowspeed sedimentation before centrifugation on the discontinuous sucrose gradients. The isolation of plasma membranes was followed by covalent labelling of the surface of dissociated gastrula cells with diazoniobenzene sulphonate, by electron microscopy and the distribution of enzymatic markers. The isolated plasma membranes have a low neural inducing activity as compared to other cell constituents. 相似文献
135.
Summary From embryos (Xenopus laevis) of different developmental stages nuclei were isolated which exert neural inducing activity in the biological test. The active material could partly be extracted from the nuclei. Experiments for the isolation of nuclear ribonucleoprotein (RNP) particles have shown that the activity is localized at least in part in these particles. On the other hand, some neural inducer is not detached from chromatin and the nuclear matrix even with ionic detergents. Inducing activity was found in germinal vesicles and to a higher degree in the cytoplasm of oocytes, but in a masked, biologically inactive state. 相似文献
136.
137.
Javaid I. Javaid Hildegard Hof Eric G. Brunngraber 《Biochimica et Biophysica Acta (BBA)/General Subjects》1975,404(1):74-82
Mannose-rich glycopeptides derived from brain glycoproteins were recovered by affinity chromatography on Concanavalin A-Sepharose. These glycopeptides, which adsorb to the lectin and are eluted with α-methylmannoside, constitute about 25–30% of the total glycopeptide material recovered from rat brain glycoproteins. They contain predominately mannose and N-acetylglucosamine (mannose/N-acetylglucosamine = 3), as well as small amounts of galactose and fucose. Approx. 65% of the Concanavalin A-binding glycopeptide carbohydrate was recovered after treatment with leucine aminopeptidase, gel filtration on Biogel P-4, and ion-exchange chromatography on coupled Dowex 50-hydrogen and Dowex 1-chrolide columns. The purified glycopeptide fraction contained six mannose and two N-acetylglucosamine residues per aspartic acid and possessed an apparent molecular weight of about 2000 as assessed by gel filtration and amino acid analysis. Galactose and fucose were absent. Treatment of the purified glycopeptides with α-mannosidase drastically reduced their affinity for Concanavalin A, suggesting the presence of one or more terminal mannose residues. 相似文献
138.
139.
Claus Kemkemer Matthias Kohn David N Cooper Lutz Froenicke Josef Högel Horst Hameister Hildegard Kehrer-Sawatzki 《BMC evolutionary biology》2009,9(1):84-24
Background
Genome comparisons have made possible the reconstruction of the eutherian ancestral karyotype but also have the potential to provide new insights into the evolutionary inter-relationship of the different eutherian orders within the mammalian phylogenetic tree. Such comparisons can additionally reveal (i) the nature of the DNA sequences present within the evolutionary breakpoint regions and (ii) whether or not the evolutionary breakpoints occur randomly across the genome. Gene synteny analysis (E-painting) not only greatly reduces the complexity of comparative genome sequence analysis but also extends its evolutionary reach. 相似文献140.