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991.
Sari SUZUKI Masashi ISHIKAWA Takuya UEDA Yasuhiro OHSHIBA Yuki MIYASAKA Kazuhiro OKUMURA Michinari YOKOHAMA Choji TAYA Kunie MATSUOKA Yoshiaki KIKKAWA 《Experimental Animals》2015,64(3):241-251
The DBA/2J strain is a model for early-onset, progressive hearing loss in humans, as
confirmed in the present study. DBA/2J mice showed progression of hearing loss to
low-frequency sounds from ultrasonic-frequency sounds and profound hearing loss at all
frequencies before 7 months of age. It is known that the early-onset hearing loss of
DBA/2J mice is caused by affects in the ahl
(Cdh23ahl) and ahl8
(Fscn2ahl8) alleles of the cadherin 23 and fascin 2 genes,
respectively. Although the strong contributions of the
Fscn2ahl8 allele were detected in hearing loss at 8- and
16-kHz stimuli with LOD scores of 5.02 at 8 kHz and 8.84 at 16 kHz, hearing loss effects
were also demonstrated for three new quantitative trait loci (QTLs) for the intervals of
50.3–54.5, 64.6–119.9, and 119.9–137.0 Mb, respectively, on chromosome 5, with significant
LOD scores of 2.80–3.91 for specific high-frequency hearing loss at 16 kHz by quantitative
trait loci linkage mapping using a (DBA/2J × C57BL/6J) F1 × DBA/2J backcross
mice. Moreover, we showed that the contribution of Fscn2ahl8
to early-onset hearing loss with 32-kHz stimuli is extremely low and raised the
possibility of effects from the Cdh23ahl allele and another
dominant quantitative trait locus (loci) for hearing loss at this ultrasonic frequency.
Therefore, our results suggested that frequency-specific QTLs control early-onset hearing
loss in DBA/2J mice. 相似文献
992.
Akira ISHIKAWA Makoto SUGIYAMA Eiichi HONDO Keiji KINOSHITA Yuki YAMAGISHI 《Experimental Animals》2015,64(2):207-220
Oca2p-cas (oculocutaneous albinism II; pink-eyed dilution
castaneus) is a coat color mutant gene on mouse chromosome 7 that arose spontaneously in
wild Mus musculus castaneus mice. Mice homozygous for
Oca2p-cas usually exhibit pink eyes and gray coat hair on
the non-agouti genetic background, and this ordinary phenotype remains unchanged
throughout life. During breeding of a mixed strain carrying this gene on the C57BL/6J
background, we discovered a novel spontaneous mutation that causes darkening of the eyes
and coat hair with aging. In this study, we developed a novel mouse model showing this
unique phenotype. Gross observations revealed that the pink eyes and gray coat hair of the
novel mutant young mice became progressively darker in color by approximately 3 months
after birth. Light and transmission-electron microscopic observations revealed a marked
increase in melanin pigmentation of coat hair shafts and choroid of the eye in the novel
mice compared to that in the ordinary mice. Sequence analysis of
Oca2p-cas revealed a 4.1-kb deletion involving exons 15
and 16 of its wild-type gene. However, there was no sequence difference between the two
types of mutant mice. Mating experiments suggested that the novel mutant phenotype was not
inherited in a simple fashion, due to incomplete penetrance. The novel spontaneous mutant
mouse is the first example of progressive hair darkening animals and is an essential
animal model for understanding of the regulation mechanisms of melanin biosynthesis with
aging. 相似文献
993.
Ai Nishimoto Yuki Tachibana Kaoru Takaura Takehiro Ochi Hironari Koyama 《Experimental Animals》2015,64(4):369-373
To confirm our hypothesis that the sex and age of cynomolgus monkeys influences the
effect of training, we employed a new training technique designed to increase the animal’s
affinity for animal care personnel. During 151 days of training, monkeys aged 2 to 10
years accepted each 3 raisins/3 times/day, and communicated with animal care personnel (5
times/day). Behavior was scored using integers between −1 and 5. Before training, 35 of
the 61 monkeys refused raisins offered directly by animal care personnel (Score −1, 0 and
1). After training, 28 of these 35 monkeys (80%) accepted raisins offered directly by
animal care personnel (>Score 2). The mean score of monkeys increased from 1.2 ± 0.1 to
4.3 ± 0.2. The minimum training period required for monkeys to reach Score 2 was longer
for females than for males. After 151 days, 6 of the 31 females and 1 of the 30 males
still refused raisins offered directly by animal care personnel. Beneficial effects of
training were obtained in both young and adult monkeys. These results indicate that our
new training technique markedly improves the affinity of monkeys for animal care
personnel, and that these effects tend to vary by sex but not age. In addition, abnormal
behavior and symptoms of monkeys were improved by this training. 相似文献
994.
995.
The vertebrate calmodulin is configured with two structurally independent globular lobes in N- and C-terminus, and a flexible central linker. Distinctly, two lobes of calmodulin from Saccharomyces cerevisiae (yCaM) interact and influence the Ca(2+)-binding profile of each other. We explored this further using the mutant proteins with eliminated Ca(2+)-binding ability in one of the lobes and found that the Ca(2+)-bound N-lobe associates with the Ca(2+)-free C-lobe to gain the Ca(2+) affinity of a wild-type level. Next, analysing series of C-terminal residue truncation mutant, we found that the truncation of C-terminal three residues induce the hyper Ca(2+) affinity. These residues are also important for the general structural behaviour of calmodulin, such as Ca(2+)-induced slow mobility shift in polyacrylamide gel electrophoresis and for the ability to activate Cmk1p (yeast calmodulin kinase). These suggest: (i) when Ca(2+) occupies only N-lobe, two lobes interact and form the stable intermediate leading to a proper level of Ca(2+) affinity; (ii) the C-terminal three residues are required to prohibit abnormal stabilization of the intermediate promoting abnormally high Ca(2+) affinity and for recognition of target enzymes. A model for Ca(2+) and target bindings of yCaM is proposed. Evolutional aspect concerning the biological significance of this model was discussed. 相似文献
996.
Kubota T Hamazoe Y Hashiguchi S Ishibashi D Akasaka K Nishida N Katamine S Sakaguchi S Kuroki R Nakashima T Sugimura K 《The Journal of biological chemistry》2012,287(17):14023-14039
We prepared β-sheet-rich recombinant full-length prion protein (β-form PrP) (Jackson, G. S., Hosszu, L. L., Power, A., Hill, A. F., Kenney, J., Saibil, H., Craven, C. J., Waltho, J. P., Clarke, A. R., and Collinge, J. (1999) Science 283, 1935-1937). Using this β-form PrP and a human single chain Fv-displaying phage library, we have established a human IgG1 antibody specific to β-form but not α-form PrP, PRB7 IgG. When prion-infected ScN2a cells were cultured with PRB7 IgG, they generated and accumulated PRB7-binding granules in the cytoplasm with time, consequently becoming apoptotic cells bearing very large PRB7-bound aggregates. The SAF32 antibody recognizing the N-terminal octarepeat region of full-length PrP stained distinct granules in these cells as determined by confocal laser microscopy observation. When the accumulation of proteinase K-resistant PrP was examined in prion-infected ScN2a cells cultured in the presence of PRB7 IgG or SAF32, it was strongly inhibited by SAF32 but not at all by PRB7 IgG. Thus, we demonstrated direct evidence of the generation and accumulation of β-sheet-rich PrP in ScN2a cells de novo. These results suggest first that PRB7-bound PrP is not responsible for the accumulation of β-form PrP aggregates, which are rather an end product resulting in the triggering of apoptotic cell death, and second that SAF32-bound PrP lacking the PRB7-recognizing β-form may represent so-called PrP(Sc) with prion propagation activity. PRB7 is the first human antibody specific to β-form PrP and has become a powerful tool for the characterization of the biochemical nature of prion and its pathology. 相似文献
997.
The pathways whereby Sox2 scans DNA to locate its specific binding site are investigated by NMR in specific and nonspecific Sox2·DNA complexes and in a specific ternary complex with Oct1 on the Hoxb1 regulatory element. Direct transfer of Sox2 between nonspecific sites on different DNA molecules occurs without dissociation into free solution at a rate of ~10(6) M(-1) s(-1), whereas one-dimensional sliding proceeds with a diffusion constant of ≥0.1 μm(2)·s(-1). Translocation of Sox2 from one specific DNA site to another occurs via jumping, involving complete dissociation into free solution (k(d) ~5-6 s(-1)) followed by reassociation (k(a) ~5 × 10(8) M(-1) s(-1)). In the presence of Oct1 bound to an adjacent specific site, k(d) is reduced by more than 10-fold. Paramagnetic relaxation measurements, however, demonstrate that sparsely populated (<1%), transient states involving nonspecifically bound Sox2 in rapid exchange with specifically bound Sox2 are sampled in both binary Sox2·DNA- and ternary Oct1·Sox2·Hoxb1-DNA-specific complexes. Moreover, Sox2 modulates the mechanism of translocation of Oct1. Both Sox2 and the Oct1 POU(HD) domain are transiently released from the specific ternary complex by sliding to an adjacent nonspecific site, followed by direct transfer to another DNA molecule, whereas the Oct1 POU(S) domain is fixed to its specific site through direct interactions with Sox2. Intermolecular translocation of POU(HD) results in the formation of a bridged intermediate spanning two DNA molecules, enhancing the probability of complete intermolecular translocation of Oct1. By way of contrast, in the specific Oct1·DNA binary complex, POU(S) undergoes direct intermolecular translocation, whereas POU(HD) scans the DNA by sliding. 相似文献
998.
Nakayama Y Matsui Y Takeda Y Okamoto M Abe K Fukumoto Y Yamaguchi N 《The Journal of biological chemistry》2012,287(30):24905-24915
Src family tyrosine kinases (SFKs) participate in mitotic signal transduction events, including mitotic entry, cleavage furrow ingression, and cytokinesis abscission. Although SFKs have been shown to associate with the mitotic spindle, the role of SFKs in mitotic spindle formation remains unclear. Here, we show that c-Src promotes proper spindle orientation in early prometaphase. Src localizes close to spindle poles in a manner independent of Src kinase activity. Three-dimensional analyses showed that Src inhibition induced spindle misorientation, exhibiting a tilting spindle in early prometaphase. Spindle misorientation is frequently seen in SYF cells, which harbor triple knock-out mutations of c-Src, c-Yes, and Fyn, and reintroduction of c-Src but not Fyn into SYF cells rescued spindle misorientation. Spindle misorientation was also observed upon Src inhibition under conditions in which Aurora B was inhibited. Inducible expression of c-Src promoted a properly oriented bipolar spindle, which was suppressed by Src inhibition. Aster formation was severely inhibited in SYF cells upon Aurora B inhibition, which was rescued by reintroduction of c-Src into SYF cells. Furthermore, reintroduction of c-Src facilitated microtubule regrowth from cold-induced depolymerization and accelerated M phase progression. These results suggest that c-Src is involved in spindle orientation through centrosome-mediated aster formation. 相似文献
999.
Nishitani G Nagai S Hayakawa S Kosaka Y Sakurada K Kamiyama T Gojobori T 《Applied and environmental microbiology》2012,78(3):813-821
Kleptoplastidy is the retention of plastids obtained from ingested algal prey, which may remain temporarily functional and be used for photosynthesis by the predator. We showed that the marine dinoflagellate Dinophysis mitra has great kleptoplastid diversity. We obtained 308 plastid rbcL sequences by gene cloning from 14 D. mitra cells and 102 operational taxonomic units (OTUs). Most sequences were new in the genetic database and positioned within Haptophyceae (227 sequences [73.7%], 80 OTUs [78.4%]), particularly within the genus Chrysochromulina. Others were closely related to Prasinophyceae (16 sequences [5.2%], 5 OTUs [4.9%]), Dictyochophyceae (14 sequences [4.5%], 5 OTUs [4.9%]), Pelagophyceae (14 sequences [4.5%], 1 OTU [1.0%]), Bolidophyceae (3 sequences [1.0%], 1 OTU [1.0%]), and Bacillariophyceae (1 sequence [0.3%], 1 OTU [1.0%]); however, 33 sequences (10.8%) as 9 OTUs (8.8%) were not closely clustered with any particular group. Only six sequences were identical to those of Chrysochromulina simplex, Chrysochromulina hirta, Chrysochromulina sp. TKB8936, Micromonas pusilla NEPCC29, Micromonas pusilla CCMP491, and an unidentified diatom. Thus, we detected >100 different plastid sequences from 14 D. mitra cells, strongly suggesting kleptoplastidy and the need for mixotrophic prey such as Laboea, Tontonia, and Strombidium-like ciliates, which retain numerous symbiotic plastids from different origins, for propagation and plastid sequestration. 相似文献
1000.
Fujii R Kita M Iinuma Y Oka N Takaesu Y Taira T Iha M Cogdell RJ Hashimoto H 《Photosynthesis research》2012,111(1-2):157-163
A chlorophyll c binding membrane intrinsic light-harvesting complex, the fucoxanthin-chlorophyll a/c protein (FCP), was isolated from cultured discoid germilings of an edible Japanese brown alga, Cladosiphon (C.) okamuranus TOKIDA (Okinawa Mozuku in Japanese). The discoid germiling is an ideal source of brown algal photosynthetic pigment-protein complexes in terms of its size and easiness of cultivation on a large scale. Ion-exchange chromatography was crucial for the purification of FCP from solubilized thylakoid proteins. The molecular weight of the purified FCP assembly was estimated to be ~56?kDa using blue native-PAGE. Further subunit analyses using 2D-PAGE revealed that the FCP assembled as a trimer consisting of two distinguishable subunits having molecular weights of 18.2 (H) and 17.5 (L)?kDa. Fluorescence and fluorescence-excitation spectra confirmed that the purified FCP assembly was functionally intact. 相似文献