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排序方式: 共有697条查询结果,搜索用时 31 毫秒
101.
An approach for sequencing the entire mitochondrial genomes (mitogenomes) of decapod crustaceans using 79 newly designed and 7 published polymerase chain reaction (PCR) primers is described. The approach comprises the following steps: (1) the entire mitogenome is amplified in 2 or 3 long PCRs; (2) the 86 primers are used in different combinations to amplify contiguous, overlapping short segments of the entire mitogenome with the diluted long PCR products as templates; (3) direct cycle sequencing is conducted using the short PCR products. This strategy allows a more rapid determination of decapod mitogenomic sequences than a traditional method using cloned mitochondrial DNA and primer walking strategy. As a practical example, the mitogenomic sequence for a kuruma prawn Marsupenaeus japonicus (Crustacea: Decapoda), was determined using the PCR-based approach. 相似文献
102.
Taniguchi A Tsuchida S Kuno S Mita M Machida T Ioritani N Terai C Yamanaka H Kamatani N 《Nucleosides, nucleotides & nucleic acids》2004,23(8-9):1141-1145
Five mutations in the adenine phosphoribosyltransferase (APRT) gene have been described in Japanese patients with APRT deficiency. We investigated the APRT gene from three patients with APRT deficiency and two novel mutations, G133D and V84M, were determined. 相似文献
103.
K Hamamoto R Koike A Shirakura N Sasaki Y Machida 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,693(2):5802
A rapid, sensitive and reproducible reversed-phase HPLC assay was developed for the determination of amprolium (APL) in chicken plasma. Protein in plasma sample was precipitated with 0.33 M perchloric acid and supernatant solution was injected into the HPLC system. Following the chromatographic separation of APL and the beclotiamine (I.S.) on a C18 column, the derivatives of APL and I.S. were formed by post-column reaction and detected by fluorescence detection (excitation at 400 nm, emission at 460 nm). The method showed excellent precision, accuracy and speed with a detection limit of 2 ng/ml. The intra- and inter-assay variance of this method were less than 11.2%. This method has been successfully applied to plasma determinations after oral administration of APL to chicken. 相似文献
104.
Relative apparent synapomorphy analysis (RASA). I: The statistical measurement of phylogenetic signal 总被引:10,自引:9,他引:1
We have developed a new approach to the measurement of phylogenetic signal
in character state matrices called relative apparent synapomorphy analysis
(RASA). RASA provides a deterministic, statistical measure of natural
cladistic hierarchy (phylogenetic signal) in character state matrices. The
method works by determining whether a measure of the rate of increase of
cladistic similarity among pairs of taxa as a function of phenetic
similarity is greater than a null equiprobable rate of increase. Our
investigation of the utility and limitations of RASA using simulated and
bacteriophage T7 data sets indicates that the method has numerous
advantages over existing measures of signal. A first advantage is
computational efficiency. A second advantage is that RASA employs known
methods of statistical inference, providing measurable sensitivity and
power. The performance of RASA is examined under various conditions of
branching evolution as the number of characters, character states per
character, and mutations per branch length are varied. RASA appears to
provide an unbiased and reliable measure of phylogenetic signal, and the
general approach promises to be useful in the development of new techniques
that should increase the rigor and reliability of phylogenetic estimates.
相似文献
105.
106.
Interest in the use of low-copy nuclear genes for phylogenetic analyses of
plants has grown rapidly, because highly repetitive genes such as those
commonly used are limited in number. Furthermore, because low- copy genes
are subject to different evolutionary processes than are plastid genes or
highly repetitive nuclear markers, they provide a valuable source of
independent phylogenetic evidence. The gene for granule-bound starch
synthase (GBSSI or waxy) exists in a single copy in nearly all plants
examined so far. Our study of GBSSI had three parts: (1) Amino acid
sequences were compared across a broad taxonomic range, including grasses,
four dicotyledons, and the microbial homologs of GBSSI. Inferred structural
information was used to aid in the alignment of these very divergent
sequences. The informed alignments highlight amino acids that are conserved
across all sequences, and demonstrate that structural motifs can be highly
conserved in spite of marked divergence in amino acid sequence. (2)
Maximum-likelihood (ML) analyses were used to examine exon sequence
evolution throughout grasses. Differences in probabilities among
substitution types and marked among-site rate variation contributed to the
observed pattern of variation. Of the parameters examined in our set of
likelihood models, the inclusion of among-site rate variation following a
gamma distribution caused the greatest improvement in likelihood score. (3)
We performed cladistic parsimony analyses of GBSSI sequences throughout
grasses, within tribes, and within genera to examine the phylogenetic
utility of the gene. Introns provide useful information among very closely
related species, but quickly become difficult to align among more divergent
taxa. Exons are variable enough to provide extensive resolution within the
family, but with low bootstrap support. The combined results of amino acid
sequence comparisons, maximum-likelihood analyses, and phylogenetic studies
underscore factors that might affect phylogenetic reconstruction. In this
case, accommodation of the variable rate of evolution among sites might be
the first step in maximizing the phylogenetic utility of GBSSI.
相似文献
107.
Yasunori Machida Marina Nakashima Kayoko Morikiyo Hiroharu Banno Masaki Ishikawa Takashi Soyano Ryuichi Nishihama 《Journal of plant research》1998,111(2):243-246
The tobaccoNPK1 gene encodes a homolog of mitogenactivated protein kinase kinase kinases. We have recently identified tobacco kinesin-like
proteins (NACK1/2) as activators for NPK1. Immunochemical analyses of NPK1 and NACK1 proteins suggest that NPK1 is involved
in the regulation of some process in the M phase of the plant cell cycle.
The extended abstract of a paper presented at the 13th International Symposium in Conjugation with Award of the International
Prize for Biology “Frontier of Plant Biology” 相似文献
108.
Oana S Machida S Hiratsuka E Furutani Y Momma K Takao A Matsuoka R 《Biology of the cell / under the auspices of the European Cell Biology Organization》1998,90(9):605-613
We have earlier reported partial cloning of a cDNA of a chick atrial myosin heavy chain (MHC) gene, CCSV2 and its expression pattern in embryonic chick hearts (Oana et al (1995) Eur J Cell Biol 67, 42-49). In this study, five overlapping cDNA clones (including CCSV2) which together encode the entire open reading frame of the chick atrial MHC gene were characterized, and both the entire nucleotide sequence consisting of 5825 bases and the deduced amino acid sequence consisting of 1931 amino acids determined. Reinvestigation of the nucleotide sequence of the previously reported and presumably different chick atrial specific MHC cDNA clone, AMHC1 (Yutzey et al (1994) Development 120, 871-883), revealed that our clone and AMHC1 encoded the same MHC. The chick atrial MHC gene was strongly expressed in developing chick atria from a very early stage (Hamburger and Hamilton stage 9, 29-33 h) to the adult stage. This gene was also expressed, although weakly, in the ventricle, somite (the precursor to skeletal muscle) and skeletal muscle during embryonic stages but not in adults. 相似文献
109.
MAP kinase links the fertilization signal transduction pathway to the G1/S-phase transition in starfish eggs. 总被引:1,自引:0,他引:1 下载免费PDF全文
The mechanism by which fertilization initiates S-phase in the zygote is examined by manipulating the activity of MAP kinase in mature starfish eggs. These unfertilized eggs, which are arrested at G1-phase after the completion of meiosis, have high MAP kinase activity but undetectable cdc2 kinase activity. Either fertilization or inhibition of protein synthesis causes a decrease in MAP kinase activity, which is followed by DNA synthesis. Inactivation of MAP kinase with its specific phosphatase, CL100, initiates DNA synthesis in the absence of fertilization, while constitutive activation of MAP kinase with MEK represses the initiation of DNA synthesis following fertilization. Thus, in unfertilized mature starfish eggs, a capacity for DNA replication is already acquired, but entry into S-phase is negatively regulated by MAP kinase activity that is supported by a continuously synthesized protein(s) but not by cdc2 kinase. Upon fertilization, downregulation of MAP kinase activity is necessary and sufficient for triggering the G1/S-phase transition. 相似文献
110.