全文获取类型
收费全文 | 1455篇 |
免费 | 56篇 |
国内免费 | 1篇 |
专业分类
1512篇 |
出版年
2022年 | 14篇 |
2021年 | 22篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 29篇 |
2015年 | 54篇 |
2014年 | 67篇 |
2013年 | 83篇 |
2012年 | 82篇 |
2011年 | 86篇 |
2010年 | 54篇 |
2009年 | 58篇 |
2008年 | 93篇 |
2007年 | 82篇 |
2006年 | 106篇 |
2005年 | 92篇 |
2004年 | 96篇 |
2003年 | 88篇 |
2002年 | 89篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 14篇 |
1997年 | 16篇 |
1996年 | 15篇 |
1995年 | 21篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1986年 | 6篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1938年 | 5篇 |
1935年 | 6篇 |
1934年 | 5篇 |
1931年 | 7篇 |
1930年 | 4篇 |
1927年 | 3篇 |
排序方式: 共有1512条查询结果,搜索用时 0 毫秒
101.
102.
Kaisho Y Watanabe T Nakata M Yano T Yasuhara Y Shimakawa K Mori I Sakura Y Terao Y Matsui H Taketomi S 《Biochemical and biophysical research communications》2005,330(3):653-657
The human MrgX3 gene, belonging to the mrgs/SNSRs (mas related genes/sensory neuron specific receptors) family, was overexpressed in transgenic rats using the actin promoter. Two animal lines showed cataracts with liquification/degeneration and swelling of the lens fiber cells. The transient epidermal desquamation was observed in line with higher gene expression. Histopathology of the transgenic rats showed acanthosis and focal parakeratosis. In the epidermis, there was an increase in cellular keratin 14, keratin 10, and loricrin, as well as PGP 9.5 in innervating nerve fibers. These phenotypes accompanied an increase in the number of proliferating cells. These results suggest that overexpression of the human MrgX3 gene causes a disturbance of the normal cell-differentiation process. 相似文献
103.
The NH(2)-terminal transmembrane and lumenal domains of LGP85 are needed for the formation of enlarged endosomes/lysosomes 总被引:1,自引:0,他引:1
Kuronita T Hatano T Furuyama A Hirota Y Masuyama N Saftig P Himeno M Fujita H Tanaka Y 《Traffic (Copenhagen, Denmark)》2005,6(10):895-906
LGP85 is a lysosomal membrane protein possessing a type III topology and is also known as a member of the CD36 superfamily of proteins, such as CD36 and the scavenger-receptor BI (SR-BI). We have recently demonstrated that overexpression of LGP85 in various mammalian cell lines causes the enlargement of endosomal/lysosomal compartments (ELCs). Using chimeras and deletion mutants, we show here that the lumenal region of LGP85 is necessary, but not sufficient, for the development of ELCs. Effective formation of enlarged ELC was largely dependent on the presence of a preceding NH2 -terminal transmembrane segment. Analyses of deletion mutants within the lumenal domain further revealed a requirement of the NH2 -terminal transmembrane proximal lumenal region, with high sequence similarity with SR-BI for the enlargement of ELC. These results suggest that an interaction of the NH2 -terminal transmembrane proximal lumenal domain of LGP85 with the inner leaflet of endosomal/lysosomal membranes through the connection with the transmembrane domain is an essential determinant for the regulation of endosomal/lysosomal membrane traffic. Interestingly, although the NH2 -terminal transmembrane domain itself was not sufficient for the enlargement of ELCs, it appeared to be required for direct targeting of LGP85 from the trans -Golgi network to late endosomes/lysosomes. Taken together, these results indicate the involvement of distinct domain of LGP85 in the targeting to, and biogenesis and maintenance of, ELC. 相似文献
104.
OVCA1 is a tumor suppressor identified by positional cloning from chromosome 17p13.3, a hot spot for chromosomal aberration in breast and ovarian cancers. It has been shown that expression of OVCA1 is reduced in some tumors and that it regulates cell proliferation, embryonic development, and tumorigenesis. However, the biochemical function of OVCA1 has remained unknown. Recently, we isolated a novel mutant resistant to diphtheria toxin and Pseudomonas exotoxin A from the gene trap insertional mutants library of Chinese hamster ovary cells. In this mutant, the Ovca1 gene was disrupted by gene trap mutagenesis, and this disruption well correlated with the toxin-resistant phenotype. We demonstrated direct evidence that the tumor suppressor OVCA1 is a component of the biosynthetic pathway of diphthamide on elongation factor 2, the target of bacterial ADP-ribosylating toxins. A functional genetic approach utilizing the random gene trap mutants library of mammalian cells should become a useful strategy to identify the genes responsible for specific phenotypes. 相似文献
105.
Harada Y Sakai M Kurabayashi N Hirota T Fukada Y 《The Journal of biological chemistry》2005,280(36):31714-31721
Cryptochrome 1 and 2 act as essential components of the central and peripheral circadian clocks for generation of circadian rhythms in mammals. Here we show that mouse cryptochrome 2 (mCRY2) is phosphorylated at Ser-557 in the liver, a well characterized peripheral clock tissue. The Ser-557-phosphorylated form accumulates in the liver during the night in parallel with mCRY2 protein, and the phosphorylated form reaches its maximal level at late night, preceding the peak-time of the protein abundance by approximately 4 h in both light-dark cycle and constant dark conditions. The Ser-557-phosphorylated form of mCRY2 is localized in the nucleus, whereas mCRY2 protein is located in both the cytoplasm and nucleus. Importantly, phosphorylation of mCRY2 at Ser-557 allows subsequent phosphorylation at Ser-553 by glycogen synthase kinase-3beta (GSK-3beta), resulting in efficient degradation of mCRY2 by a proteasome pathway. As assessed by phosphorylation of GSK-3beta at Ser-9, which negatively regulates the kinase activity, GSK-3beta exhibits a circadian rhythm in its activity with a peak from late night to early morning when Ser-557 of mCRY2 is highly phosphorylated. Altogether, the present study demonstrates an important role of sequential phosphorylation at Ser-557/Ser-553 for destabilization of mCRY2 and illustrates a model that the circadian regulation of mCRY2 phosphorylation contributes to rhythmic degradation of mCRY2 protein. 相似文献
106.
Nateglinide, a novel oral hypoglycemic agent, possesses a carbonyl group and a peptide-type bond in its structure. We previously reported that nateglinide transport occurs via a single system that may be identical to the ceftibuten/H(+) cotransport system by the rat small intestine. We speculated that the absorption system present on the intestinal epithelium may be similar to that found on the renal tubular epithelium. The aim of this study was to characterize the transporters on the apical side of the kidney that may contribute to the reabsorption of ceftibuten and nateglinide. The uptake of nateglinide by rat renal brush-border membranes is associated with an H(+)-coupled transport system. Ceftibuten competitively inhibited H(+)-dependent nateglinide uptake. In contrast, Gly-Sar, cephradine and cephalexin had no effect on nateglinide uptake. Nateglinide competitively inhibited H(+)-driven transporter-mediated ceftibuten uptake. We conclude that nateglinide transport occurs via a single system that is H(+)-dependent and may be identical to the ceftibuten/H(+) cotransport system. 相似文献
107.
We performed a quantitative trait locus (QTL) analysis of eight body weights recorded weekly from 3 weeks to 10 weeks after birth and two weight gains recorded between 3 weeks and 6 weeks, and between 6 weeks and 10 weeks in an inter-sub-specific backcross population of wild Mus musculus castaneus mice captured in the Philippines and the common inbred strain C57BL/6J ( M. musculus domesticus ), to elucidate the complex genetic architecture of body weight and growth. Interval mapping identified 17 significant QTLs with main effects on 11 chromosomes. In particular, the main effect of the most potent QTL on proximal chromosome 2 increased linearly with age, whereas other QTLs exerted effects on either the early or late growth period. Surprisingly, although wild mice displayed 60% of the body size of their C57BL/6J counterparts, the wild-derived allele enhanced growth at two QTLs. Interestingly, five of the 17 main-effect QTLs identified had significant epistatic interaction effects. Five new epistatic QTLs with no main effects were identified on different chromosomes or regions. For one pair of epistatic QTLs, mice that were heterozygous for the wild-derived allele at one QTL and homozygous for that allele at another QTL exhibited the most rapid growth in all four possible genotypic combinations. Out of the identified QTLs, several showed significant sex-specific effects. 相似文献
108.
Bis(pyridine) complexes of molybdenum and tungsten, [M(η3-allyl)Cl(CO)2(NC5H5)2] (M=Mo; 3-Mo, M=W; 3-W), reacted with an equimolar amount of lithiated amidinate, Li[(PhN)2CR] (R=H; 4a-Li, R = CH3; 4b-Li), to yield corresponding amidinato(pyridine) complexes, [M(η3-allyl){(PhN)2CR}(CO)2(NC5H5)] (M=Mo, R=H; 5a-Mo, M=Mo, R=CH3; 5b-Mo, M=W, R=H; 5a-W), as a yellow solid. The dissociation of pyridine ligand from the central metal in complexes 5a was observed in a polar solvent such as acetonitrile. In these cases, although the formation of amidinato(acetonitrile) complexes, [M(η3-allyl){(PhN)2CH}(CO)2(NCMe)] (M=Mo; 6a-Mo, M=W; 6a-W), was suggested spectroscopically, isolation of complexes 6a was not successful but the re-formation of pyridine complexes 5a was observed. In the reactions of complexes 5a with PEt3 and with P(OMe)3, the substitution reactions easily took place to give [M(η3-allyl){(PhN)2CH}(CO)2(PEt3)] (M=Mo; 7a-Mo, M=W; 7a-W) and [M(η3-allyl){(PhN)2CH}(CO)2{P(OMe)3}] (M=Mo; 8a-Mo, M=W; 8a-W), respectively. These complexes were characterized spectroscopically as well as, in some cases, by X-ray analyses. 相似文献
109.
Singlet oxygen, generated during photosynthesis, is a strong oxidant that can, potentially, damage various molecules of biological importance. We investigated the effects in vivo of singlet oxygen on the photodamage to photosystem II (PSII) in the cyanobacterium Synechocystis sp. PCC 6803. Increases in intracellular concentrations of singlet oxygen, caused by the presence of photosensitizers, such as rose bengal and ethyl eosin, stimulated the apparent photodamage to PSII. However, actual photodamage to PSII, as assessed in the presence of chloramphenicol, was unaffected by the production of singlet oxygen. These observations suggest that singlet oxygen produced by added photosensitizers acts by inhibiting the repair of photodamaged PSII. Labeling of proteins in vivo revealed that singlet oxygen inhibited the synthesis of proteins de novo and, in particular, the synthesis of the D1 protein. Northern blotting analysis indicated that the accumulation of psbA mRNAs, which encode the D1 protein, was unaffected by the production of singlet oxygen. Subcellular localization of polysomes with bound psbA mRNAs suggested that the primary target of singlet oxygen might be the elongation step of translation. 相似文献
110.
Wang D Kobayashi T Zhou L Nagahama Y 《Biochemical and biophysical research communications》2004,320(1):83-89
A Foxl2 cDNA was cloned from the Nile tilapia ovary by RT-PCR and subsequent RACE. Alignment of known Foxl2 sequences from vertebrates confirmed the conservation of the Foxl2 open reading frame and protein sequences, especially the forkhead domain and C-terminal region, while some homopolymeric runs of amino acids are found only in mammals but not in non-mammalian vertebrates. RT-PCR revealed that Foxl2 is expressed in the tilapia brain (B), pituitary (P), gill, and gonads (G), with the highest level of expression in the ovary, reflecting the involvement of Foxl2 in B-P-G axis. Northern blotting and in situ hybridization also revealed an evident sexual dimorphic expression pattern in the gonads. Foxl2 mRNA was mainly detected in the granulosa cells surrounding the oocytes. The ovarian expression of Foxl2 in tilapia begins early during the differentiation of the gonads and persists until adulthood, implying the involvement of Foxl2 in fish gonad differentiation and the maintenance of ovarian function. 相似文献