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101.
H. Lippert K. Iken C. Volk M. Kck E. Rachor 《Journal of experimental marine biology and ecology》2004,310(2):131-146
The development of chemical defences in marine organisms is supposed to be driven by intense pressure of predation and competition. While benthic communities in tropical and also Antarctic regions are thought to be mainly structured by intra- and interspecific interactions, these factors are proposed to be less important in northern high latitudes. Consequently, selective pressure for chemical defence should be low in these regions. To investigate the incidence of chemical defence against predation in northern high latitudes, crude extracts of 18 abundant sessile or slow-moving invertebrate species (4 sponges, 3 actinians, 1 soft coral, 4 bryozoans, 3 ascidians and the egg mass of a gastropod) from Kongsfjord (Spitsbergen) were tested for feeding deterrent activity. Laboratory assays were performed by offering artificial food with extracts to two different predators, the amphipod Anonyx nugax which is a common species in Kongsfjord, and the starfish Asterias rubens from the North Sea. Of the 18 extracts tested, 2 (Haliclona viscosa, Hormathia nodosa) exhibited significant feeding deterrent effects in the amphipod assay. Furthermore, 6 extracts had a significantly stimulating effect on the amphipod feeding, and 10 extracts did not affect consumption. In the starfish assay, only the crude extract of H. viscosa was significantly rejected. For H. viscosa, feeding deterrence could be established for two pure compounds, and for H. nodosa for one fraction. The present data show that feeding deterrent compounds are present in sub-Arctic marine invertebrates from Kongsfjord but are less abundant than in temperate, tropical and Antarctic species. 相似文献
102.
Synthesis, Storage, and Release of Vascular Endothelial Growth Factor/Vascular Permeability Factor (VEGF/VPF) by Human Mast Cells: Implications for the Biological Significance of VEGF206 总被引:9,自引:0,他引:9 下载免费PDF全文
103.
Jiří Šponer Michal Sabat Jaroslav V. Burda Jerzy Leszczynski Pavel Hobza Bernhard Lippert 《Journal of biological inorganic chemistry》1999,4(5):537-545
Ab initio calculations have been carried out to characterize the structure and energetics of a silver(I) complex with the
cytosine-adenine DNA base pair and an aqua ligand in the coordination sphere of Ag. In addition, we have also studied analogous
complexes with Cu(I) and Au(I), and structures in which adenine has been replaced by purine in order to investigate the structural
role of the adenine amino group. The calculations revealed that all metal-modified structures are dominated by the metal-base
interactions, while the water-metal ion interaction and many-body interligand repulsion are less important contributions.
Nevertheless, the structural role of the water molecule in the complex is quite apparent and in agreement with an earlier
crystallographic study. The metal-modified base pairs exhibit large conformational flexibility toward out-of-plane motions
(propeller twist and buckle), comparable or, in some cases, even larger than that observed in the base pairs without metal
ions. All structures have been optimized within the Hartree-Fock approximation, while interaction energies were evaluated
with the inclusion of electron correlation.
Received: 25 March 1999 / Accepted: 10 June 1999 相似文献
104.
The secreted acid phosphatase (SAcP) of L.donovani is a heterogeneous glycoprotein that displays a wide array of N- and O-linked glycosylations. The O-linked sugars are of particular interest due to their similarity to the phosphoglycan structures of the major lipophosphoglycan surface antigen and released phosphoglycan (Turco et al., 1987; Greis et al., 1992). This study describes a structural analysis of the SAcP O-linked glycosylations using mass spectroscopy, amino acid sequencing, and enzymatic carbohydrate sequencing. Analysis of glycan chain lengths and peptide glycosylation site distribution was performed, revealing that the average O-linked structure was approximately 32 repeat units in length. Amino acid sequence analysis of glycosylated peptides showed that phosphoglycosylations did not occur randomly but were localized to specific serine residues within an array of degenerate serine/threonine-rich repeat sequences localized in the C-terminus. No evidence was obtained for modification of threonine residues. The observed pattern suggested that a consensus sequence may exist for localization of phosphoglycan structures. 相似文献
105.
Metabolic correction of congenital erythropoietic porphyria with iPSCs free of reprogramming factors
A Bedel M Taillepierre V Guyonnet-Duperat E Lippert P Dubus S Dabernat T Mautuit B Cardinaud C Pain B Rousseau M Lalanne C Ged Y Duchartre E Richard H de Verneuil F Moreau-Gaudry 《American journal of human genetics》2012,91(1):109-121
Congenital erythropoietic porphyria (CEP) is due to a deficiency in the enzymatic activity of uroporphyrinogen III synthase (UROS); such a deficiency leads to porphyrin accumulation and results in skin lesions and hemolytic anemia. CEP is a candidate for retrolentivirus-mediated gene therapy, but recent reports of insertional leukemogenesis underscore the need for safer methods. The discovery of induced pluripotent stem cells (iPSCs) has opened up new horizons in gene therapy because it might overcome the difficulty of obtaining sufficient amounts of autologous hematopoietic stem cells for transplantation and the risk of genotoxicity. In this study, we isolated keratinocytes from a CEP-affected individual and generated iPSCs with two excisable lentiviral vectors. Gene correction of CEP-derived iPSCs was obtained by lentiviral transduction of a therapeutic vector containing UROS cDNA under the control of an erythroid-specific promoter shielded by insulators. One iPSC clone, free of reprogramming genes, was obtained with a single proviral integration of the therapeutic vector in a genomic safe region. Metabolic correction of erythroblasts derived from iPSC clones was demonstrated by the disappearance of fluorocytes. This study reports the feasibility of porphyria gene therapy with the use of iPSCs. 相似文献
106.
107.
From cisplatin to artificial nucleases — the role of metal ion-nucleic acid interactions in biology 总被引:1,自引:0,他引:1
Bernhard Lippert 《Biometals》1992,5(4):195-208
Metal ions and metal coordination compounds bind to nucleic acids in a variety of ways, ranging from weak electrostatic interactions via hydrogen bonding and/or van der Waals forces to strong covalent binding. Metal ions naturally take part in the formation and the degradation of nucleic acids, and the propensity of certain metal coordination compounds to bind to nucleic acids, notably DNA, is enploited in cancer chemotherapy. Moreover, metal compounds have a wide potential as chemical probes for nucleic acid structures and as tools for nucleic acid processing. 相似文献
108.
Background
The KdpD/KdpE two-component system of Escherichia coli regulates expression of the kdpFABC operon encoding the high affinity K+ transport system KdpFABC. The input domain of KdpD comprises a domain that belongs to the family of universal stress proteins (Usp). It has been previously demonstrated that UspC binds to this domain, resulting in KdpD/KdpE scaffolding under salt stress. However the mechanistic significance of this domain for signaling remains unclear. Here, we employed a "domain swapping" approach to replace the KdpD-Usp domain with four homologous domains or with the six soluble Usp proteins of E. coli. 相似文献109.
D.G. Kieback H.P. Zahradnik L Quaas E.E. Krner-Fehmel T.H. Lippert 《Prostaglandins & other lipid mediators》1986,32(1)
In an open randomized clinical trial 100 pregnant women with low Bishop Scores at term were treated either with intracervical Prostaglandin (PG) E2 (0.5 mg in 2.5 ml triacetin-gel) 12 hours before labor induction with intravenous oxytocin or with oxytocin infusion alone. In 46 of the 50 pretreated patients (92 %) the Bishop Score progressed at least 3 points, in four cases only 2 points. The mean Bishop score in the untreated patients increased insignificantly. After PGE2-gel administration 16 patients delivered during the 12 hour interval compared to 3 in the group without pretreatment. The first induction attempt was successful in 14 (64 %) of the 22 patients that were left to be induced after cervical softening and in 26 (57 %) of the 47 women without cervical priming. The Cesarean section rate was 10% (n=5) in the PGE2-gel group and 12% (n=6) in the control group. Dosage of oxytocin required for labor induction was significantly lower after cervical softening. No serious fetal or maternal side effects were observed after PGE2 pretreatment. 相似文献
110.
The impact of endogenous estradiol metabolites on carcinogenesis 总被引:1,自引:0,他引:1
The available literature on estrogen metabolism and estrogen metabolites involved in carcinogenesis is reviewed. Endogenous estradiol metabolism leads to metabolic products that can have various, and, to some extent, contrary, biologic effects. Thus, there are numerous research findings on the stimulation and inhibition of cancer growth by estrogen metabolites. Furthermore, there are indications that, in certain types of cancer, the production of growth-stimulating estradiol metabolites is increased. There are also reports on substances that can influence estradiol metabolism. So far, only a few estradiol metabolites have been examined with respect to their influence on the development and growth of cancer. It is presumed that other metabolites can also intervene directly or indirectly in the cancer process, but there is a great lack of research in this area. An understanding of the actions of estradiol metabolites may open up new avenues for the therapy of malignant diseases. Although little is known about the biologic effects of most of the estradiol metabolites, the reported actions of certain estradiol metabolites already justify clinical investigations on their possible beneficial uses in tumor therapy. 相似文献