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151.
In zebrafish, primordial germ cells (PGCs) are determined by a specialized maternal cytoplasm, the germ plasm, which forms at the distal ends of the cleavage furrows in 4-cell embryos. The germ plasm includes maternal mRNAs from the germline-specific genes such as vasa and nanos1, and vegetally localized dazl RNA is also incorporated into the germ plasm. However, little is known about the distributions and assembly mechanisms of germ plasm components, especially during oogenesis. Here we report that the germ plasm RNAs vasa, nanos1, and dazl co-localize with the mitochondrial cloud (MC) and are transported to the vegetal cortex during early oogenesis. We found that a mitochondrial cloud localization element (MCLE) previously identified in the 3' untranslated region (3'UTR) of Xenopus Xcat2 gene can direct RNA localization to the vegetal cortex via the MC in zebrafish oocytes. In addition, the RNA-binding protein Hermes is a component of the MC in zebrafish oocytes, as is the case in Xenopus. Moreover, we provide evidence that the dazl 3'UTR possesses at least three types of cis-acting elements that direct multiple steps in the localization process: MC localization, anchorage at the vegetal cortex, and localization at the cleavage furrows. Taken together, the data show that the MC functions as a conserved feature that participates in transport of the germ plasm RNAs in Xenopus and zebrafish oocytes. Furthermore, we propose that the germ plasm components are assembled in a stepwise and spatiotemporally-regulated manner during oogenesis and early embryogenesis in zebrafish. 相似文献
152.
Analysis of molecular inversion probe performance for allele copy number determination 总被引:1,自引:1,他引:0
Wang Y Moorhead M Karlin-Neumann G Wang NJ Ireland J Lin S Chen C Heiser LM Chin K Esserman L Gray JW Spellman PT Faham M 《Genome biology》2007,8(11):R246-14
We have developed a new protocol for using molecular inversion probes to accurately and specifically measure allele copy number. The new protocol provides for significant improvements, including the reduction of input DNA (from 2 μg) by more than 25-fold (to 75 ng total genomic DNA), higher overall precision resulting in one order of magnitude lower false positive rate, and greater dynamic range with accurate absolute copy number up to 60 copies. 相似文献
153.
Kuroita T Kanno T Kawai A Kawakami B Oka M Endo Y Tozawa Y 《Extremophiles : life under extreme conditions》2007,11(1):85-94
We have isolated and characterized a gene for a putative protein-disulfide oxidoreductase (phdsb) in the archaeon Pyrococcus horikoshii. The open reading frame of phdsb encodes a protein of 170 amino acids with an NH2-terminal extension similar to the bacterial signal peptides. The putative mature region of PhDsb includes a sequence motif,
Cys-Pro-His-Cys (CPHC), that is conserved in members of the bacterial DsbA family, but otherwise the archaeal and bacterial
sequences do not show substantial similarity. A recombinant protein corresponding to the predicted mature form of PhDsb behaved
as a monomer and manifested oxidoreductase activities in vitro similar to those of DsbA of Escherichia coli. The catalytic activity of PhDsb was thermostable and was shown by mutation analysis to depend on the NH2-terminal cysteine residue of the CPHC motif. Thus, in spite of their low overall sequence similarities, DsbA-like proteins
of archaea and bacteria appear to be highly similar in terms of function. 相似文献
154.
155.
Takahashi Miyuki Takasugi Toshiyuki Kawakami Arisa Wei Ran Ando Kanae Ohshima Toshio Hisanaga Shin-ichi 《Neurochemical research》2022,47(9):2773-2779
Neurochemical Research - Valproic acid (VPA) is a drug used for the treatment of epilepsy, seizures, migraines, and bipolar disorders. Cyclin-dependent kinase 5 (Cdk5) is a Ser/Thr kinase activated... 相似文献
156.
Yuichi Mishima Chanika D. Jayasinghe Kai Lu Junji Otani Masahiro Shirakawa Toru Kawakami Hironobu Kimura Hironobu Hojo Peter Carlton Shoji Tajima Isao Suetake 《Nucleic acids research》2015,43(21):10200-10212
The α, β and γ isoforms of mammalian heterochromatin protein 1 (HP1) selectively bind to methylated lysine 9 of histone H3 via their chromodomains. Although the phenotypes of HP1-knockout mice are distinct for each isoform, the molecular mechanisms underlying HP1 isoform-specific function remain elusive. In the present study, we found that in contrast to HP1α, HP1γ could not bind tri-methylated H3 lysine 9 in a reconstituted tetra-nucleosomes when the nucleosomes were in an uncompacted state. The hinge region connecting HP1''s chromodomain and chromoshadow domain contributed to the distinct recognition of the nucleosomes by HP1α and HP1γ. HP1γ, but not HP1α, was strongly enhanced in selective binding to tri-methylated lysine 9 in histone H3 by the addition of Mg2+ or linker histone H1, which are known to induce compaction of nucleosomes. We propose that this novel property of HP1γ recognition of lysine 9 in the histone H3 tail in different nucleosome structures plays a role in reading the histone code. 相似文献
157.
Arild Husby Takeshi Kawakami Lars R?nneg?rd Linnéa Smeds Hans Ellegren Anna Qvarnstr?m 《Proceedings. Biological sciences / The Royal Society》2015,282(1806)
Understanding the genetic basis of traits involved in adaptation is a major
challenge in evolutionary biology but remains poorly understood. Here, we use
genome-wide association mapping using a custom 50 k single nucleotide
polymorphism (SNP) array in a natural population of collared flycatchers to
examine the genetic basis of clutch size, an important life-history trait in
many animal species. We found evidence for an association on chromosome 18 where
one SNP significant at the genome-wide level explained 3.9% of the
phenotypic variance. We also detected two suggestive quantitative trait loci
(QTLs) on chromosomes 9 and 26. Fitness differences among genotypes were
generally weak and not significant, although there was some indication of a
sex-by-genotype interaction for lifetime reproductive success at the suggestive
QTL on chromosome 26. This implies that sexual antagonism may play a role in
maintaining genetic variation at this QTL. Our findings provide candidate
regions for a classic avian life-history trait that will be useful for future
studies examining the molecular and cellular function of, as well as
evolutionary mechanisms operating at, these loci. 相似文献
158.
Amanda Carroll-Portillo Judy L. Cannon Joost te Riet Anna Holmes Yuko Kawakami Toshiaki Kawakami Alessandra Cambi Diane S. Lidke 《The Journal of cell biology》2015,210(5):851-864
Mast cells (MCs) produce soluble mediators such as histamine and prostaglandins that are known to influence dendritic cell (DC) function by stimulating maturation and antigen processing. Whether direct cell–cell interactions are important in modulating MC/DC function is unclear. In this paper, we show that direct contact between MCs and DCs occurs and plays an important role in modulating the immune response. Activation of MCs through FcεRI cross-linking triggers the formation of stable cell–cell interactions with immature DCs that are reminiscent of the immunological synapse. Direct cellular contact differentially regulates the secreted cytokine profile, indicating that MC modulation of DC populations is influenced by the nature of their interaction. Synapse formation requires integrin engagement and facilitates the transfer of internalized MC-specific antigen from MCs to DCs. The transferred material is ultimately processed and presented by DCs and can activate T cells. The physiological outcomes of the MC–DC synapse suggest a new role for intercellular crosstalk in defining the immune response. 相似文献
159.
To H Yoshimatsu H Tomonari M Ida H Tsurumoto T Tsuji Y Sonemoto E Shimasaki N Koyanagi S Sasaki H Ieiri I Higuchi S Kawakami A Ueki Y Eguchi K 《Chronobiology international》2011,28(3):267-274
Methotrexate (MTX) is the most important drug for treating rheumatoid arthritis (RA). It has been stated that cytokines play an important role in the pathogenesis of RA, and that cytokine levels increase and show 24-h rhythms in RA patients. Previously, we found that arthritis was relieved after the administration of MTX at specific times in synchronization with the 24-h rhythm of tumor necrosis factor (TNF)-α in collagen-induced arthritis (CIA) animals. Based on our findings in an earlier study of the dosing time-dependent effects of MTX in MRL/lpr mice, which develop autoimmune disorders that share similarities with human RA, we examined here the utility of MTX chronotherapy in Japanese RA patients. In an initial animal modeling study, we collected blood from MRL/lpr mice at different times (2, 6, 10, 14, 18, or 22 hours after the light was turned on [HALO]), and we measured TNF-α mRNA expression in leukocytes. MTX was administered to the mice at two different dosing times (6 or 18 HALO), and various blood parameters were measured to estimate arthritis activity. TNF-α mRNA levels showed a clear 24-h rhythm with a peak at 22 HALO and a trough at 18 HALO after RA had developed. In these MRL/lpr mice, inflammation and TNF-α were markedly reduced when the MTX dosing time was matched to the time (18 HALO) when the TNF-α level began to increase. We then applied these findings to Japanese RA patients by switching them from the standard MTX three times/wk (day 1: after breakfast and supper; day 2: after breakfast schedule), to chronotherapy, in which the dose and number of doses/wk were not changed but MTX was administered once-a-day at bedtime. Disease Activity Score (DAS)28, modified health assessment questionnaire (MHAQ), and adverse effects were assessed. With MTX chronotherapy, DAS28, which is commonly used to quantitatively assess RA symptoms, was significantly improved at all follow-up clinical visit times compared with the baseline (vs. 1 mo: p?=?.0197, 2 mos: p?=?.0107, 3 mos: p?=?.0087). Significant symptom recovery was observed in 41.2% of patients, and 23.5% of patients achieved clinical remission during the 3 mos of follow-up. Functional capacity of RA patients, as indicated by the MHAQ, was markedly improved by chronotherapy. There were no severe adverse effects. Thus, we demonstrated (i) inflammation and plasma TNF-α concentrations were significantly reduced in MRL/lpr mice treated with MTX at 18 HALO, the time when TNF-α mRNA level began to increase; and (ii) MTX bedtime chronotherapy was safe, markedly reduced disease activity, and improved the functional capacity of RA patients. The findings on RA patients show that bedtime MTX chronotherapy can improve RA symptoms compared to the current standard dosing methods. 相似文献
160.
Zebrafish eggs used as bioreactors for the production of bioactive tilapia insulin-like growth factors 总被引:1,自引:0,他引:1
Shao-Yang Hu Chia-Hsuan Liao Yi-Pei Lin Yen-Hsing Li Hong-Yi Gong Gen-Hwa Lin Koichi Kawakami Tzu-Hsuan Yang Jen-Leih Wu 《Transgenic research》2011,20(1):73-83
Multiple advantages-including the short generation time, large numbers of fertilized eggs, low cost of cultivation and easy
maintenance favor the use of fish as bioreactors for the production of pharmaceutical proteins. In the present study, zebrafish
eggs were used as bioreactors to produce mature tilapia insulin-like growth factors (IGFs) proteins using the oocyte-specific
zona pellucida (zp3) promoter. The chimeric expression plasmids, pT2-ZP-tIGFs-IRES-hrGFP, in which hrGFP was used as reporter of tilapia IGFs
expression, were designed to established Tg (ZP:tIGFs:hrGFP) transgenic lines for the expression of tilapia IGF-1 and IGF-2. Recombinant tilapia IGF-1 and IGF-2 were expressed as soluble
forms in cytoplasm of fertilized eggs. The content level of tilapia IGF-1 and IGF-2 were 6.5 and 5.0% of the soluble protein,
respectively. Using a simple Ni–NTA affinity chromatography purification process, 0.58 and 0.49 mg of purified tilapia IGF-1
and IGF-2 were obtained, respectively, from 650 fertilized eggs. The biological activity of the purified tilapia IGF-1 and
IGF-2 was confirmed via a colorimetric bioassay to monitor the growth stimulation of zebrafish embryonic cells (ZF4), tilapia
ovary cells (TO-2) and human osteosarcoma epithelial cells (U2OS). These results demonstrate that the use of zebrafish eggs
as bioreactors is a promising approach for the production of biological recombinant proteins. 相似文献