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991.
Kaoru Kuriiwa Satoru N. Chiba Hiroyuki Motomura Keiichi Matsuura 《Ichthyological Research》2014,61(4):361-374
To investigate the influence of the Kuroshio Current on the high diversity of marine fishes in Japanese waters, the intraspecific phylogeographic structure of Blacktip Grouper, Epinephelus fasciatus, was determined. The genetic analysis of E. fasciatus indicated three intraspecific mtDNA lineages representing different evolutionary histories: the first lineage differentiated in Japanese waters during a long period of fluctuations of the ancient Kuroshio Current, the second lineage, widely distributed in the tropical western Pacific, was transported to Japanese waters by the Kuroshio Current and the third lineage was distributed primarily around the Ogasawara (Bonin) Islands. Present-day sympatric distributions of the three lineages, characterized by different ratios of such individuals at each geographic site, indicated a complex genetic pattern that was classified into three demographic groups, the dispersal and gene flows of which were strongly influenced by the Kuroshio Current and factors such as countercurrent and island arc. Genetic breaks in E. fasciatus populations were congruent with other fish faunal boundaries in Japanese waters. 相似文献
992.
Yoshikazu Hasegawa Yoko Daitoku Seiya Mizuno Yoko Tanimoto Saori Mizuno-Iijima Miki Matsuo Noriko Kajiwara Masatsugu Ema Hisashi Oishi Yoshihiro Miwa Kazuyuki Mekada Atsushi Yoshiki Satoru Takahashi Fumihiro Sugiyama Ken-ichi Yagami 《Experimental Animals》2014,63(2):183-191
Cre/loxP system-mediated site-specific recombination is utilized to study gene function
in vivo. Successful conditional knockout of genes of interest is
dependent on the availability of Cre-driver mice. We produced and characterized pancreatic
β cell-specific Cre-driver mice for use in diabetes mellitus research. The gene encoding
Cre was inserted into the second exon of mouse Ins1 in a bacterial
artificial chromosome (BAC). Five founder mice were produced by microinjection of
linearized BAC Ins1-cre. The transgene was integrated between
Mafa and the telomere on chromosome 15 in one of the founders, BAC
Ins1-cre25. To investigate Cre-loxP recombination, BAC Ins1-cre25 males were crossed with
two different Cre-reporters, R26R and R26GRR females. On gross observation, reporter
signal after Cre-loxP recombination was detected exclusively in the adult pancreatic
islets in both F1 mice. Immunohistological analysis indicated that Cre-loxP
recombination-mediated reporter signal was colocalized with insulin in pancreatic islet
cells of both F1 mice, but not with glucagon. Moreover, Cre-loxP recombination
signal was already observed in the pancreatic islets at E13.5 in both F1
fetuses. Finally, we investigated ectopic Cre-loxP recombination for
Ins1, because the ortholog Ins2 is also expressed in the
brain, in addition to the pancreas. However, there was no Cre-loxP recombination-mediated
reporter signal in the brain of both F1 mice. Our data suggest that BAC
Ins1-cre25 mice are a useful Cre-driver C57BL/6N for pancreatic β cell-specific Cre-loxP
recombination, except for crossing with knock-in mice carrying floxed gene on chromosome
15. 相似文献
993.
Mai Thi Nhu Tran Junko Tanaka Michito Hamada Yuka Sugiyama Shota Sakaguchi Megumi Nakamura Satoru Takahashi Yoshihiro Miwa 《Experimental Animals》2014,63(3):311-319
Fluorescent proteins with light wavelengths within the optical window are one of the
improvements in in vivo imaging techniques. Near-infrared (NIR)
fluorescent protein (iRFP) is a stable, nontoxic protein that emits fluorescence within
the NIR optical window without the addition of exogenous substrate. However, studies
utilizing an in vivo iRFP model have not yet been published. Here, we
report the generation of transgenic iRFP mice with ubiquitous NIR fluorescence expression.
iRFP expression was observed in approximately 50% of the offspring from a matings between
iRFP transgenic and WT mice. The serum and blood cell indices and body weights of iRFP
mice were similar to those of WT mice. Red fluorescence with an excitation wavelength of
690 nm and an emission wavelength of 713 nm was detected in both newborn and adult iRFP
mice. We also detected fluorescence emission in whole organs of the iRFP mice, including
the brain, heart, liver, kidney, spleen, lung, pancreas, bone, testis, thymus, and adipose
tissue. Therefore, iRFP transgenic mice may therefore be a useful tool for various types
of in vivo imaging. 相似文献
994.
Masato Fujii Kenji Suzuki Satoru Suenaga Mariko Wakatsuki Yoshihiro Kushida Maki Touma Masamichi Hosono 《Experimental Animals》2014,63(2):155-167
Neonatal thymectomy (NTx) induces autoimmune gastritis (AIG) in BALB/c mice, a model for
human type A chronic atrophic gastritis, but not in DBA/2 mice and rarely in CDF1 mice (a
hybrid of BALB/c and DBA/2 mice). The aim of this study was to clarify the mechanisms of
AIG-resistance in mice bearing the dominant trait of DBA/2. Linkage groups associated
with, and cells related to AIG resistance were examined with CDF1-BALB/c backcrosses.
Intracellular staining and flow-cytometric bead array for several cytokines were performed
on NTx BALB/c mice and NTx DBA/2-chimeric BALB/c mice receiving DBA/2-bone marrow cells.
In NTx BALB/c mice, IFN-γ-secreting CD4+ T cells were increased, but not in NTx
DBA/2 mice. Because Vβ6+ T cell-bearing mice of half of their backcrosses
developed AIG, but the other half of Vβ6+ T cell-negative mice developed
scarcely, resistance for AIG generation is associated with the presence of the
Mls-1a locus on chromosome 1 in DBA/2 mice, which deletes
Vβ6+ T cells. NTx DBA/2-chimera BALB/c mice showed dominant production of
IL-10 and resistance for AIG, although the deletion of Vβ6+ T cells was found
not to be a cause of AIG-resistance from Mls-1a locus segregation
experiments. Although NTx DBA/2-chimeric BALB/c mice did not suffer from AIG, they brought
immediate precursors of T cells for AIG. It is concluded that DBA/2 mice generate bone
marrow-derived cells that produce anti-inflammatory cytokines to prevent the activation of
AIG-T cells. 相似文献
995.
Hamilton HW Nishiguchi G Hagen SE Domagala JD Weber PC Gracheck S Boulware SL Nordby EC Cho H Nakamura T Ikeda S Watanabe W 《Bioorganic & medicinal chemistry letters》2002,12(20):2981-2983
A series of novel benzthiodiazepinones was studied as antiherpetic agents. Significant improvements in potency and therapeutic index in a viral replication assay were realized over the starting molecule. The role of stereospecific substitution on the diazepine ring and optimal nitrogen substitution were investigated. 相似文献
996.
Satoru Morikawa Yo Mabuchi Sadafumi Suzuki Takehiko Sunabori Yasuo Nagai Hideyuki Okano 《Biochemical and biophysical research communications》2009,379(4):1114-773
Mesenchymal stem cells (MSCs) are a heterogeneous subset of stromal stem cells isolated from many adult tissues. Previous studies reported that MSCs can differentiate to both mesodermal and neural lineages by a phenomenon referred to as ‘‘dedifferentiation’’ or ‘‘transdifferentiation’’. However, since MSCs have only been defined in vitro, much of their development in vivo is still unknown. Here, we prospectively identified MSCs in the bone marrow from adult transgenic mice encoding neural crest-specific P0-Cre/Floxed-EGFP and Wnt1-Cre/Floxed-EGFP. EGFP-positive MSCs formed spheres that expressed neural crest stem cell genes and differentiated into neurons, glial cells, and myofibroblasts. Interestingly, we observed MSCs both in the GFP+ and GFP− fraction and found that there were no significant differences in the in vitro characteristics between these two populations. Our results suggest that MSCs in adult bone marrow have at least two developmental origins, one of which is the neural crest. 相似文献
997.
Anna Pfeifer Kazunori Zikihara Satoru Tokutomi Tilman Kottke 《Biophysical journal》2009,96(4):1462-1470
Phototropins are plant blue-light photoreceptors containing two light-, oxygen-, or voltage-sensitive (LOV) domains and a C-terminal kinase domain. The two LOV domains bind noncovalently flavin mononucleotide as a chromophore. We investigated the photocycle of fast-recovery mutant LOV2-I403V from Arabidopsis phototropin 2 by step-scan Fourier transform infrared spectroscopy. The reaction of the triplet excited state of flavin with cysteine takes place with a time constant of 3 μs to yield the covalent adduct. Our data provide evidence that the flavin is unprotonated in the productive triplet state, disfavoring an ionic mechanism of bond formation. An intermediate adduct species was evident that displayed changes in secondary structure in the helix or loop region, and relaxed with a time constant of 120 μs. In milliseconds, the final adduct state is formed by further alterations of secondary structure, including β-sheets. A comparison with wild-type adduct spectra shows that the mutation does not interfere with the functionality of the domain. All signals originate from within the LOV domain, because the construct does not comprise the adjacent Jα helix required for signal transduction. The contribution of early and late adduct intermediates to signal transfer to the Jα helix outside of the domain is discussed. 相似文献
998.
Hirotaka Imai Nao Hakkaku Ryo Iwamoto Jyunko Suzuki Toshiyuki Suzuki Yoko Tajima Kumiko Konishi Shintaro Minami Shizuko Ichinose Kazuhiro Ishizaka Seiji Shioda Satoru Arata Masuhiro Nishimura Shinsaku Naito Yasuhito Nakagawa 《The Journal of biological chemistry》2009,284(47):32522-32532
Phospholipid hydroperoxide glutathione peroxidase (GPx4) is an intracellular antioxidant enzyme that directly reduces peroxidized phospholipids. GPx4 is strongly expressed in the mitochondria of testis and spermatozoa. We previously found a significant decrease in the expression of GPx4 in spermatozoa from 30% of infertile human males diagnosed with oligoasthenozoospermia (Imai, H., Suzuki, K., Ishizaka, K., Ichinose, S., Oshima, H., Okayasu, I., Emoto, K., Umeda, M., and Nakagawa, Y. (2001) Biol. Reprod. 64, 674–683). To clarify whether defective GPx4 in spermatocytes causes male infertility, we established spermatocyte-specific GPx4 knock-out mice using a Cre-loxP system. All the spermatocyte-specific GPx4 knock-out male mice were found to be infertile despite normal plug formation after mating and displayed a significant decrease in the number of spermatozoa. Isolated epididymal GPx4-null spermatozoa could not fertilize oocytes in vitro. These spermatozoa showed significant reductions of forward motility and the mitochondrial membrane potential. These impairments were accompanied by the structural abnormality, such as a hairpin-like flagella bend at the midpiece and swelling of mitochondria in the spermatozoa. These results demonstrate that the depletion of GPx4 in spermatocytes causes severe abnormalities in spermatozoa. This may be one of the causes of male infertility in mice and humans. 相似文献
999.
Katsumi Doi Yasuhiro Fujino Fumio Inagaki Ryouichi Kawatsu Miki Tahara Toshihisa Ohshima Yoshihiro Okaue Takushi Yokoyama Satoru Iwai Seiya Ogata 《Applied and environmental microbiology》2009,75(8):2406-2413
The effects of silicic acid on the growth of Thermus thermophilus TMY, an extreme thermophile isolated from a siliceous deposit formed from geothermal water at a geothermal power plant in Japan, were examined at 75°C. At concentrations higher than the solubility of amorphous silica (400 to 700 ppm SiO2), a silica-induced protein (Sip) was isolated from the cell envelope fraction of log-phase TMY cells grown in the presence of supersaturated silicic acid. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the molecular mass and pI of Sip to be about 35 kDa and 9.5, respectively. Induction of Sip expression occurred within 1 h after the addition of a supersaturating concentration of silicic acid to TM broth. Expression of Sip-like proteins was also observed in other thermophiles, including T. thermophilus HB8 and Thermus aquaticus YT-1. The amino acid sequence of Sip was similar to that of the predicted solute-binding protein of the Fe3+ ABC transporter in T. thermophilus HB8 (locus tag, TTHA1628; GenBank accession no. ; GeneID, 3169376). The sip gene (987-bp) product showed 87% identity with the TTHA1628 product and the presumed Fe3+-binding protein of T. thermophilus HB27 (locus tag TTC1264; GenBank accession no. NC_006461; GeneID, 2774619). Within the genome, sip is situated as a component of the Fbp-type ABC transporter operon, which contains a palindromic structure immediately downstream of sip. This structure is conserved in other T. thermophilus genomes and may function as a terminator that causes definitive Sip expression in response to silica stress.Occurring mainly in the form of silica (SiO2), silicon (Si) is the second-most abundant element in the earth''s crust, accounting for 28.8% of the earth''s mass ( NC_00583534). SiO2 exists as monosilicic acid (Si(OH)4) in aqueous solution, as represented in the following equation: SiO2 + 2H2O · (Si(OH)4). The solubility of silica greatly depends on temperature, pH (17), and salt concentration, among other parameters (27). As the temperature of a silicic acid solution declines, its concentration can exceed the solubility of amorphous silica. Under those conditions, silicic acid polymerizes to form polysilisic acid, which is relatively stable in aqueous solution because the repulsion between the negative charges on its surface keeps it from readily aggregating and precipitating. In a geothermal reservoir, at high temperature and pressure, the silicic acid concentration at equilibrium shows the solubility of quartz. However, when that geothermal water is discharged to the surface, the silicic acid concentration becomes supersaturated as the water boils, frequently leading to the formation of siliceous deposits called “silica sinter” (11). Microscopic observation of such siliceous deposits reveals many microbe-like structures (20), and it has been suggested that these fossils represent archean microorganisms that grew in the hot, supersaturated fluids (26). There have been a number of experimental studies carried out with the aim of characterizing the physical changes associated with various bacteria during silicification (23, 26, 31, 33, 37); however, the effect of silica on the bacterial habitat in geothermal environments and the mechanism by which siliceous deposits are formed remain unexplained.Recent studies have shown that biosilicification in geothermal areas reflects the activities of various thermophilic microorganisms (15, 23, 29). For instance, geothermal water and the water discharged from hydrothermal vents contain a high concentration of silicic acid, and biogenic textures covered with amorphous silica have been found in areas around both sources (12, 22). Moreover, in a study of experimental silicification, interactions were observed between silica and Sulfurihydrogenibium azorense, a representative member of the order Aquificales (26). Still, the effect of silica on the bacterial habitat in thermal environments and the molecular properties affecting aggregation and siliceous deposition remain poorly understood.Our previous studies have focused on the effect of bacteria on the formation of siliceous deposits in geothermal water (18, 21). Siliceous deposits (called silica scale) that form in pipelines and on surface equipment in geothermal power plants cause serious economic problems related to energy loss and to plant maintenance throughout the world (38). We also observed that a Thermus strain isolated from silica scale (TMY) was able to efficiently generate and deposit amorphous silica in vitro, beginning in the latter part of the log growth phase (19). On the basis of its morphological, physiological, and genetic properties, the organism was identified as a strain of Thermus thermophilus, and its distinct properties were indicative of the microdiversity of T. thermophilus strains (14). Thermus strains are the predominant heterotrophs in natural geothermal and hydrothermal habitats, and thus far, the genomes of T. thermophilus strains HB8 (GenBank accession no. ) and HB27 (GenBank accession no. AP008226) have been sequenced completely ( AE01722116). Given its genomic similarity to T. thermophilus HB8, we analyzed the genetic information of strain TMY in that context.Here we report the effect of silicic acid concentration on the growth of T. thermophilus TMY, which was isolated from a siliceous deposit formed at a geothermal electric power plant. Notably, supersaturated silicic acid markedly stimulated expression of one cell envelope protein, which we named silica-induced protein (Sip). Induction of Sip expression occurred rapidly after the cells were exposed to supersaturated silicic acid, and the amino acid sequence of Sip showed significant similarity with the Fe3+ ABC transporters observed in other Thermus strains. These results shed new light on the growth and biosilisification associated with thermophiles in geothermal environments. 相似文献
1000.
Corticotropin-releasing factor (CRF) is a major regulatory peptide in the hypothalamic-pituitary-adrenal (HPA) axis under stress conditions. In response to stress, CRF, produced in the hypothalamic paraventricular nucleus, releases adrenocorticotropic hormone (ACTH) from the anterior pituitary (AP). ACTH in turn stimulates the release of glucocorticoid from the adrenal glands. Glucocorticoid then inhibits hypothalamic production of CRF and pituitary production of ACTH. Mice lacking a functional gene for CRF (CRF KO) showed severe impairment of the HPA axis, indicating that CRF is required for its regulation. We applied oligonucleotide microarray analysis to the AP of CRF KO to identify gene expression induced by CRF. Twenty-four genes showed less than 60% expression in CRF KO compared with normal mice. Real-time PCR analysis revealed that p21-activated kinase 3 (Pak3), prohormone convertase type 1 (PC1), and CRF-binding protein (BP) mRNA expression levels were increased by CRF in AP cells. Both Pak3 and PC1 were also increased by dexamethasone in AP cells, while CRF-BP mRNA levels were reduced. Therefore, both Pak3 and PC1 mRNA levels would be regulated by both CRF and glucocorticoids. Pak3 knockdown inhibited CRF-induced cell viability in AtT-20 cells, suggesting the important role of Pak3 in the proliferation of corticotrophs. 相似文献