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51.
Neri C Ghelardini C Sotak B Palmiter RD Guarna M Stefano G Bianchi E 《Journal of neurochemistry》2008,106(6):2337-2344
Morphine, the most used compound among narcotic analgesics, has been shown to be endogenously present in different mammalian/invertebrate normal tissues. In this study, we used mice that cannot make dopamine due to a genetic deletion of tyrosine hydroxylase specifically in dopaminergic neurons, to test the hypothesis that endogenous dopamine is necessary to endogenous morphine formation in vivo in mammalian brain. When dopamine was lacking in brain neurons, endogenous morphine was missing in brain mouse whereas it could be detected in brain from wild type rodent at a picogram range. Our data prove for the first time that endogenous dopamine is necessary to endogenous morphine formation in normal mammalian brain. Morphine synthesis appears to be originated from dopamine through L-tyrosine in normal brain tissue. Morphine synthesis is not considered to occur inside the same neuron in normal tissue; released dopamine might be transported into morphinergic neuron and further transformed into morphine. A physiological role for endogenous morphine is suggested considering that dopamine could modulate thermal threshold through endogenous morphine formation in vivo. Thus, dopamine and endogenous opiates/opioid peptides may be interconnected in the physiological processes; yet, endogenous morphine may represent a basic link of this chain. 相似文献
52.
53.
The discovery of green fluorescent protein (GFP) from jellyfish Aequorea victoria has provoked numerous studies to unveil the myriads of biomedical applications. Consequently, several studies also revealed the prevalence of fluorescence in different marine and terrestrial organisms. However, since GFP's discovery or the Nobel prize award on GFP, the fluorescence has not been explored so far from India. The current study presents the widespread fluorescent organisms resources available in India for biomedical and toxicological applications. Fluorescence emission from different plant and animal components were examined by direct observations using UV torchlight. Investigation revealed that blue light excited fluorescence in several organisms. For the first time, this study observed GFP like fluorescence in many terretrial and marine organisms of India. Observations are indicating that fluorescent proteins have essential ecological functions that are yet to be determined. The examined plant and animal components were not bioluminescent. In comparison, the potential untouched research areas on fluorescence aspects are detailed. A thorough review of fluorescent organisms reported hitherto is also provided to spread the current knowledge on fluorescence. 相似文献
54.
The molecular evolution of sperm bindin in six species of sea urchins (Echinoida: Strongylocentrotidae) 总被引:5,自引:3,他引:2
The acrosomal protein bindin attaches sperm to eggs during sea urchin
fertilization. Complementary to ongoing functional biochemical studies, I
take a comparative approach to explore the molecular evolution of bindin in
a group of closely related free-spawning echinoid species. Two alleles of
the mature bindin gene were sequenced for each of six species in the sea
urchin family Strongylocentrotidae. The nucleotide sequences diverged by at
least 1% per Myr at both silent and replacement sites. Two short sections
flanking the conserved block show an excess of nonsynonymous substitutions.
Each is homologous to a region that had been identified as a target of
selection in other sea urchin comparisons. A large proportion of the
bindin-coding sequence consists of a highly variable repeat region. Bindin
sequences, even including the large intron, could not resolve the branching
order among five of the species.
相似文献
55.
Seed morphology and anatomy of Austrotaxus spicata (Taxaceae) and its systematic position 总被引:1,自引:0,他引:1
ALEXEY V. F. CH. BOBROV ALEXANDER P. MELIKIAN MIKHAIL S. ROMANOV ALEXEY N. SOROKIN 《Botanical journal of the Linnean Society. Linnean Society of London》2004,145(4):437-443
The anatomy and ultrastructure of seed envelopes of a New Caledonian endemic Austrotaxus spicata were examined for the first time. The systematic position and phylogenetic relations of Austrotaxus were analysed in light of these data. The structure of aril and spermoderm were investigated to demonstrate the similarities with Phyllocladus as well as with Taxus and Pseudotaxus . On the basis of all female reproductive organ characters, Austrotaxus appeared to be fairly isolated and its placing in the independent family Austrotaxaceae was confirmed from the standpoint of comparative anatomy of the seed coat. Taking into consideration that the heterobathmy of features can be the most distinctively traced in the structure of reproductive organs, evaluating the extent of evolutionary advancement of Austrotaxus seems to be rather difficult. However, it is evident that the relationship of Austrotaxus either with Taxaceae or with Podocarpaceae s.l . is considerably remote. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 437–443. 相似文献
56.
The goal of the study was to characterize the optimal developmental stage of zygotic embryo expiants of the hardwood forest tree species yellow-poplar (Liriodendron tulipifera L.) for the initiation of embryogenic cultures, using morphological measurements and polypeptide profiles of the embryos. Developing zygotic embryos from seeds of six full-sib families, collected every two weeks from 4 weeks postpollination until seed maturity (18 weeks postpollination) were divided into 2 subsamples for each collection date. One group was used to initiate tissue cultures. Embryos in the other group were measured (total length, cotyledon length and hypocotyl thickness) and soluble polypeptide profiles of the embryos were analyzed by SDS-polyacrylamide gel electrophoresis. Potential of an expiant to produce an embryogenic culture peaked during the eighth week following pollination, with an average of 28% of the expiants producing proembryogenic masses, and declined to near zero for mature zygotic embryos. The maximum embryogenic potential corresponded to the globular stage of embryo developmet. Soluble protein profiles of zygotic embryos from 5 sampling dates indicated that decline in embryogenic potential appeared to parallel an increase in the level of a polypeptide of approximately 55 kDa, possibly a storage protein.Abbreviations BA
Benzyladenine
- 2,4-D
2,4-dichlorophenoxyacetic acid
- CH
Casein hydrolysate
- SDS-PAGE
Sodium dodecylsulfate polyacrylamide gel electrophoresis
- PEM
Proembryogenic mass 相似文献
57.
58.
Transformation of sugarcane protoplasts by direct uptake of a selectable chimaeric gene 总被引:6,自引:0,他引:6
W. H. Chen K. M. A. Gartland M. R. Davey R. Sotak J. S. Gartland B. J. Mulligan J. B. Power E. C. Cocking 《Plant cell reports》1987,6(4):297-301
Sugarcane protoplasts were transformed to kanamycin resistance at a frequency of approximately 8 in 107 following PEG-induced uptake of Sma1 linearised pABD1 plasmid. DNA-treated protoplasts were cultured in agarose droplets, and protoplast-derived transformants selected on 80 g ml–1 kanamycin. Transformed tissues maintained on this level of antibiotic expressed APH(3)II activity, and contained DNA that hybridised to a probe with the APH(3)II gene.Abbreviations APH(3)II
aminoglycoside phosphotransferase
- PEG
polyethylene glycol
- 2,4-D
2,4-dichlorophenoxyacetic acid 相似文献
59.
Structure and organization of the bovine beta-globin genes 总被引:1,自引:0,他引:1
Genomic clones spanning the entire cow beta-globin gene locus have been
isolated and characterized. These clones demonstrate that the linkage of
embryonic-like (epsilon) genes and pseudogenes (psi) to the previously
described fetal (gamma) and adult (beta) genes is as follows: 5'-epsilon
3-epsilon 4-psi 3-beta-epsilon 1-epsilon 2-psi 1- psi 2-gamma-3'. Present
data indicate that, like that of the goat, the fetal and adult genes arose
via block duplication of an ancestral four- gene set:
epsilon-epsilon-psi-beta. This duplication event preceded the divergence of
cows and goats, which occurred greater than or equal to 18-20 Myr ago.
However, cows do not have the additional four-gene block containing a
preadult/stress globin gene (beta C). Furthermore, the cow fetal cluster
contains an extra beta-like pseudogene, which apparently arose by a
small-scale duplication. The fixation of this duplication may indicate a
possible evolutionary role for pseudogenes.
相似文献
60.
Summary A novel nickel resistant, hyperaccumulatingN.crassa nir-2 mutant, isolated by us, sequestered 90% of Ni2+ from medium with 120 mg/l Ni2+. The parent wild strain showed comparable efficiency only at much lower concentrations (<10mg/l). The initial rapid rate and efficiency of Ni2+ removal could be maintained beyond 2 h by fresh addition of mycelial biomass. The results have been discussed from the stand point of the utility of metal resistant fungi in the control of environmental pollution. 相似文献