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181.
Cloning of Quail Tyrosine Hydroxylase: Amino Acid Homology with Other Hydroxylases Discloses Functional Domains 总被引:7,自引:6,他引:1
Mireille Fauquet Brigitte Grima Annie Lamouroux Jacques Mallet 《Journal of neurochemistry》1988,50(1):142-148
A cDNA clone containing the entire coding region of quail tyrosine hydroxylase (TH) has been isolated and analyzed. Comparison with rat and human THs and phenylalanine hydroxylases reveals several highly conserved domains. Two of them, shared by all these hydroxylases, are localized in the central and C-terminal parts of the molecules, and most probably include the active site. Two others are found only in the TH molecules. One contains putative sites of phosphorylation and is implicated in the posttranslational regulation of the enzyme. The second highly preserved domain, consisting of a stretch of 21 amino acids, is presumably associated with an important feature of the enzyme that remains to be identified. 相似文献
182.
A. E. González C. Schöpke N. J. Taylor R. N. Beachy C. M. Fauquet 《Plant cell reports》1998,17(11):827-831
A protocol was developed for Agrobacterium-mediated transformation of embryogenic suspension cultures of cassava. The bacterial strain ABI containing the binary vector
pMON977 with the nptII gene as selectable marker and an intron-interrupted uidA gene (encoding β-glucuronidase) as visible marker was used for the experiments. Selection of transformed tissue with paromomycin resulted
in the establishment of antibiotic-resistant, β-glucuronidase-expressing lines of friable embryogenic callus, from which embryos and subsequently plants were regenerated.
Southern blot analysis demonstrated stable integration of the uidA gene into the cassava genome in five lines of transformed embryogenic suspension cultures and in two plant lines. 相似文献
183.
Zhang Shiping Song Wen-Yuan Chen Lili Ruan Deling Taylor Nigel Ronald Pamela Beachy Roger Fauquet Claude 《Molecular breeding : new strategies in plant improvement》1998,4(6):551-558
The agronomically important Indica (group 1) rice varieties IR64, IR72, hybrid restorer line Minghui 63, and BG90-2 were co-transformed by microbombardment of embryogenic suspensions with plasmids that contain the Xa21 gene which confers resistance to Xanthomonas oryzae pv. oryzae and the hph gene for resistance to hygromycin B. Six of the 55 transgenic R0 plant lines containing the Xa21 gene displayed high levels of resistance to the pathogen, and no partial resistance was observed. The trait was stably inherited in subsequent generations, and transgenic plants are currently in field tests. The ability to transfer agronomically important genes into elite Indica rice varieties demonstrates the applicability of genetic engineering for the agronomic improvement of rice. 相似文献
184.
Conservation of alternative splicing and genomic organization of the myosin alkali light-chain (Mlc1) gene among Drosophila species 总被引:3,自引:0,他引:3
The Mlc1 gene of Drosophila melanogaster encodes two MLC1 isoforms via
developmentally regulated alternative pre-mRNA splicing. In larval muscle
and tubular and abdominal muscles of adults, all of the six exons are
included in the spliced mRNA, whereas, in the fibrillar indirect flight
muscle of adult, exon 5 is excluded from the mRNA. We show that this
tissue-specific pattern of alternative splicing of the Mlc1 pre-mRNA is
conserved in D. simulans, D. pseudoobscura, and D. virilis. Isolation and
sequencing of the Mlc1 genes from these three other Drosophila species have
revealed that the overall organization of the genes is identical and that
the genes have maintained a very high level of sequence identity within the
coding region. Pairwise amino acid identities are 94%-99%, and there are no
charge changes among the proteins. Total nucleotide divergence within the
coding region of the four genes supports the accepted genealogy of these
species, but the data indicate a significantly higher rate of amino acid
replacement in the branch leading to D. pseudoobscura. A comparison of
nucleotide substitutions in the coding portions of exon 5 and exon 6, which
encode the alternative carboxyl termini of the two MLC1 isoforms, suggests
that exon 5 is subject to greater evolutionary constraints than is exon 6.
In addition to the coding sequences, there is significant sequence
conservation within the 5' and 3' noncoding DNA and two of the introns,
including one that flanks exon 5. These regions are candidates for cis-
regulatory elements. Our results suggest that evolutionary constraints are
acting on both the coding and noncoding sequences of the Mlc1 gene to
maintain proper expression and function of the two MLC1 polypeptides.
相似文献
185.
Partial desiccation of mature embryo-derived calli,a simple treatment that dramatically enhances the regeneration ability of indica rice 总被引:7,自引:0,他引:7
Iann M. Rancé Wenzhong Tian Helena Mathews Alexandre de Kochko Roger N. Beachy Claude Fauquet 《Plant cell reports》1994,13(11):647-651
Regeneration of indica rice varieties remains a limiting factor for researchers undertaking rice Iransformation experiments. As reported for japonica rice and other crops, partial desiccation of indica rice calli dramatically promotes organogenesis and leads to high regeneration ability. We are now able to obtain 66.5%, 61.1% and 73.7% of calli that regenerate plants for the indica varieties TN1, IR72 and IR64 whereas in non desiccated controls only 30.0%, 15.5% and 18.7% of calli regenerated, respectively. Plants obtained were phenotypically normal and 50% were highly fertile. Partial desiccation is a reliable and simple method for improving indica rice regeneration. It also shortens the time of in vitro culture.Abbreviations 2,4-D
2,4-Dichlorophenoxyacetic acid
- BAP
6-Benzyl amino purine
- DTT
Dithiothreitol
- EDTA
Ethylene diamine tetra-acetic acid
- MS
Murashige and Skoog
- NAA
Naphtalene acetic acid
- PAGE
Polyacrylamide gel electrophoresis
- PAR
Photosynthetic active radiation
- SDS
Sodium dodecil sulfate 相似文献
186.
BLA Verçosa CM Lemos IL Mendonça SMMS Silva SM de Carvalho H Goto FAL Costa 《BMC veterinary research》2008,4(1):45
Background
Visceral leishmaniasis in Brazil is caused by the protozoan Leishmania (Leishmania) chagasi and it is transmitted by sandfly of the genus Lutzomyia. Dogs are an important domestic reservoir, and control of the transmission of visceral leishmaniasis (VL) to humans includes the elimination of infected dogs. However, though dogs are considered to be an important element in the transmission cycle of Leishmania, the identification of infected dogs representing an immediate risk for transmission has not been properly evaluated. Since it is not possible to treat infected dogs, they are sacrificed when a diagnosis of VL is established, a measure that is difficult to accomplish in highly endemic areas. In such areas, parameters that allow for easy identification of reservoirs that represents an immediate risk for transmission is of great importance for the control of VL transmission. In this study we aimed to identify clinical parameters, reinforced by pathological parameters that characterize dogs with potential to transmit the parasite to the vector.Results
The major clinical manifestations of visceral leishmaniasis in dogs from an endemic area were onicogriphosis, skin lesions, conjunctivitis, lymphadenopathy, and weight loss. The transmission potential of these dogs was assessed by xenodiagnosis using Lutzomyia longipalpis. Six of nine symptomatic dogs were infective to Lutzomyia longipalpis while none of the five asymptomatic dogs were infective to the sandfly. Leishmania amastigotes were present in the skin of all clinically symptomatic dogs, but absent in asymptomatic dogs. Higher parasite loads were observed in the ear and ungueal region, and lower in abdomen. The inflammatory infiltrate was more intense in the ears and ungueal regions of both symptomatic and asymptomatic dogs. In clinically affected dogs in which few or none Leishmania amastigotes were observed, the inflammatory infiltrate was constituted mainly of lymphocytes and macrophages. When many parasites were present, the infiltrate was also comprised of lymphocytes and macrophages, as well as a larger quantity of polymorphonuclear neutrophils (PMNs).Conclusion
Dogs that represent an immediate risk for transmission of Leishmania in endemic areas present clinical manifestations that include onicogriphosis, skin lesions, conjunctivitis, lymphadenopathy, and weight loss. Lymphadenopathy in particular was a positive clinical hallmark since it was closely related to the positive xenodiagnosis.187.
Survey of Malassezia sp and dermatophytes in the cutaneous microbiome of free‐ranging golden‐headed lion tamarins (Leontopithecus chrysomelas ‐ Kuhl, 1820)
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188.
Geminiviruses and RNA silencing 总被引:1,自引:0,他引:1
189.
190.
Microparticle bombardment as a tool in plant science and agricultural biotechnology 总被引:11,自引:0,他引:11
Microparticle bombardment technology has evolved as a method for delivering exogenous nucleic acids into plant cells and is a commonly employed technique in plant science. Desired genetic material is precipitated onto micron-sized metal particles and placed within one of a variety of devices designed to accelerate these "microcarriers" to velocities required to penetrate the plant cell wall. In this manner, transgenes can be delivered into the cell's genome or plastome. Since the late 1980s microparticle bombardment has become a powerful tool for the study of gene expression and production of stably transformed tissues and whole transgenic plants for experimental purposes and agricultural applications. This paper reviews development and application of the technology, including the protocols and mechanical systems employed as delivery systems, and the types of plant cells and culture systems employed to generate effective "targets" for receiving the incoming genetic material. Current understanding of how the exogenous DNA becomes integrated into the plant's native genetic background are assessed as are methods for improving the efficiency of this process. Pros and cons of particle bombardment technologies compared to alternative direct gene transfer methods and Agrobacterium based transformation systems are discussed. 相似文献