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排序方式: 共有585条查询结果,搜索用时 31 毫秒
81.
Tomoaki Hishida Eric Vazquez-Ferrer Yuriko Hishida-Nozaki Ignacio Sancho-Martinez Yuta Takahashi Fumiyuki Hatanaka Jun Wu Alejandro Ocampo Pradeep Reddy Min-Zu Wu Laurie Gerken Reuben J. Shaw Concepcion Rodriguez Esteban Christopher Benner Hiroshi Nakagawa Pedro Guillen Garcia Estrella Nu ez Delicado Antoni Castells Josep M. Campistol Guang-Hui Liu Juan Carlos Izpisua Belmonte 《蛋白质与细胞》2019,10(7):485
Identification of the precise molecular pathways involved in oncogene-induced transformation may help us gain a better understanding of tumor initiation and promotion. Here, we demonstrate that SOX2+ foregut epithelial cells are prone to oncogenic transformation upon mutagenic insults, such as KrasG12D and p53 deletion. GFP-based lineage-tracing experiments indicate that SOX2+ cells are the cells-of-origin of esophagus and stomach hyperplasia. Our observations indicate distinct roles for oncogenic KRAS mutation and P53 deletion. p53 homozygous deletion is required for the acquisition of an invasive potential, and KrasG12D expression, but not p53 deletion, suffices for tumor formation. Global gene expression analysis reveals secreting factors upregulated in the hyperplasia induced by oncogenic KRAS and highlights a crucial role for the CXCR2 pathway in driving hyperplasia. Collectively, the array of genetic models presented here demonstrate that stratified epithelial cells are susceptible to oncogenic insults, which may lead to a better understanding of tumor initiation and aid in the design of new cancer therapeutics. 相似文献
82.
Comparative studies of the ecological and genetic traits of Panonychus citri (McGregor) populations on citrus and other host
plants were conducted. Panonychus citri on Osmanthus trees has a unique esterase allele and host range in comparison with
populations on other host plants, for example Citrus unshiu and Ilex crenata. Reproductive incompatibility between P. citri
populations on C. unshiu and Osmanthus fragrans was found. Therefore, in Japan, P. citri differentiates into two groups one
of which associates with Osmanthus, and the other with other host plants.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
83.
Yusaku Hioki Kyoko Ogasahara Soo Jae Lee Jichun Ma Masami Ishida Yuriko Yamagata Yoshiki Matsuura Motonori Ota Mitsunori Ikeguchi Seiki Kuramitsu Katsuhide Yutani 《European journal of biochemistry》2004,271(13):2624-2635
The structure of the tryptophan synthase beta2 subunit (Pfbeta2) from the hyperthermophile, Pyrococcus furiosus, was determined by X-ray crystallographic analysis at 2.2 A resolution, and its stability was examined by DSC. This is the first report of the X-ray structure of the tryptophan synthase beta2 subunit alone, although the structure of the tryptophan synthase alpha2beta2 complex from Salmonella typhimurium has already been reported. The structure of Pfbeta2 was essentially similar to that of the beta2 subunit (Stbeta2) in the alpha2beta2 complex from S. typhimurium. The sequence alignment with secondary structures of Pfbeta and Stbeta in monomeric form showed that six residues in the N-terminal region and three residues in the C-terminal region were deleted in Pfbeta, and one residue at Pro366 of Stbeta and at Ile63 of Pfbeta was inserted. The denaturation temperature of Pfbeta2 was higher by 35 degrees C than the reported values from mesophiles at approximately pH 8. On the basis of structural information on both proteins, the analyses of the contributions of each stabilization factor indicate that: (a) the higher stability of Pfbeta2 is not caused by either a hydrophobic interaction or an increase in ion pairs; (b) the number of hydrogen bonds involved in the main chains of Pfbeta is greater by about 10% than that of Stbeta, indicating that the secondary structures of Pfbeta are more stabilized than those of Stbeta and (c) the sequence of Pfbeta seems to be better fitted to an ideally stable structure than that of Stbeta, as assessed from X-ray structure data. 相似文献
84.
Keiko Hayashi Yoshikatsu Fujita Taketo Ashizawa Fumihiko Suzuki Yoshiaki Nagamura Yuriko Hayano‐Saito 《The Plant journal : for cell and molecular biology》2016,85(1):46-56
The hypersensitive response (HR) of plants is one of the earliest responses to prevent pathogen invasion. A brown dot lesion on a leaf is visual evidence of the HR against the blast fungus Magnaporthe oryzae in rice, but tracking the browning process has been difficult. In this study, we induced the HR in rice cultivars harboring the blast resistance gene Pit by inoculation of an incompatible M. oryzae strain, which generated a unique resistance lesion with a brown ring (halo) around the brown fungal penetration site. Inoculation analysis using a plant harboring Pit but lacking an enzyme that catalyzes tryptamine to serotonin showed that high accumulation of the oxidized form of serotonin was the cause of the browning at the halo and penetration site. Our analysis of the halo browning process in the rice leaf revealed that abscisic acid enhanced biosynthesis of serotonin under light conditions, and serotonin changed to the oxidized form via hydrogen peroxide produced by light. The dramatic increase in serotonin, which has a high antioxidant activity, suppressed leaf damage outside the halo, blocked expansion of the browning area and attenuated inhibition of plant growth. These results suggest that serotonin helps to reduce biotic stress in the plant by acting as a scavenger of oxygen radicals to protect uninfected tissues from oxidative damage caused by the HR. The deposition of its oxide at the HR lesion is observed as lesion browning. 相似文献
85.
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87.
Epidermal growth factor signals attenuate phenotypic and functional development of neocortical GABA neurons
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88.
Honda T Tajima H Kaneko Y Ban M Inaba T Takeno Y Okamoto K Aono H 《Bioorganic & medicinal chemistry letters》2008,18(9):2939-2943
We found 4-pyridylmethylthio derivative 1 to be very effective in using antiangiogenesis activity to prevent proliferation of HUVECs (Human Umbilical Vein Endothelial Cells), which was induced by vascular endothelial growth factor (VEGF). Compound 1 was equally effective in inhibiting VEGF receptor2 tyrosine kinase (KDR, IC50 = 26 nM). We deduced that the inhibition was the result of binding the catalytic domain of VEGF receptor2 tyrosine kinase in a similar fashion to both phthalazine derivative PTK787 2 and anthranylamide derivative AAL993 3. In this report, we will describe the conformational analyses, from ab initio MO calculation and X-ray crystallographic analyses, of compound 1 and the analogs, which include non-active 9, all in comparison with 2 and 3. The conformation–activity relationships suggest that a nonbonded intramolecular interaction between the sulfur and the carbonyl oxygen of 1 was very important in inhibiting KDR. 相似文献
89.
We isolated the 5′ flanking region of a gene for phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) from Pinus taeda, PtaPAL. To investigate the tissue-specific expression of the PtaPAL promoter, histochemical assay of GUS activity was performed using the transgenic tobacco expressing the PtaPAL promoter-GUS. The region of −897 to −420 in PtaPAL promoter showed high activities in the secondary xylem and response to bending stress. To characterize the cis-regulatory functions of the promoters for enzymes in phenylpropanoid biosynthesis, we examined the activity of chimeric promoters
of PtaPAL and a 4-coumarate CoA ligase, Pta4CLα. The chimeric promoter showed similar activity as the Pta4CLα promoter. Electrophoretic mobility shift assays implicated −897 to –674 of PtaPAL promoter containing cis-elements of the expression in xylem of Pinus taeda. The results suggested that AC elements of PtaPAL have multiple functions in the expression under the various developmental stages and stress conditions in the transgenic
tobacco.
The nucleotide sequence data reported will appear in the EMBL, GenBank, and DDBJ Nucleotide Sequence Databases under the accession
number AB449103 (PtaPAL promoter sequence). 相似文献
90.
A p-xylene-degrading, sulfate-reducing enrichment culture was characterized by analyzing the response of its members to changes
in the available substrate. The culture was inoculated into media containing other substrates, resulting in the establishment
of benzoate-, acetate-, and lactate-utilizing enrichment cultures. PCR-denaturing gradient gel electrophoresis (DGGE) analysis
of the enriched cultures targeting 16S rRNA genes showed quite simple band patterns. The predominant band from the benzoate-utilizing
enrichment culture was identical to that from the original enrichment culture utilizing p-xylene. A single, dominant DGGE band was observed in common from the acetate- and lactate-utilizing enrichment cultures.
A novel sulfate-reducing bacterium, strain PL12, was isolated from the lactate-utilizing enrichment culture. The 16S rRNA
gene sequence of strain PL12 was identical to that of the dominant DGGE band in the acetate- and lactate-utilizing enrichment
cultures and distinct from the dominant sequences in the original p-xylene-degrading and benzoate-utilizing enrichment cultures. Phylogenetic analysis of the 16S rRNA gene sequences showed
that the isolate belonged to the family Desulfobacteraceae in the class Deltaproteobacteria. The isolated strain PL12 could utilize n-hexane and n-decane as substrates, but could not utilize benzoate, p-xylene and other aromatic hydrocarbons. These results suggest that the p-xylene degradation observed in the original enrichment culture was performed by the dominant bacterium corresponding to DGGE
band pXy-K-13 (Nakagawa et al. 2008). The novel strain PL12 might have been utilizing metabolites of p-xylene. 相似文献