全文获取类型
收费全文 | 390篇 |
免费 | 33篇 |
专业分类
423篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 14篇 |
2015年 | 23篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 32篇 |
2011年 | 39篇 |
2010年 | 18篇 |
2009年 | 17篇 |
2008年 | 28篇 |
2007年 | 22篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有423条查询结果,搜索用时 0 毫秒
1.
Growth and other characteristics of a cell line (SP-8) established from Shope virus-induced cutaneous papilloma of domestic rabbit 总被引:1,自引:0,他引:1
2.
Electrotransformation of Thiobacillus ferrooxidans with plasmids containing a mer determinant. 下载免费PDF全文
T Kusano K Sugawara C Inoue T Takeshima M Numata T Shiratori 《Journal of bacteriology》1992,174(20):6617-6623
The mer operon from a strain of Thiobacillus ferrooxidans (C. Inoue, K. Sugawara, and T. Kusano, Mol. Microbiol. 5:2707-2718, 1991) consists of the regulatory gene merR and an operator-promoter region followed by merC and merA structural genes and differs from other known gram-negative mer operons. We have constructed four potential shuttle plasmids composed of a T. ferrooxidans-borne cryptic plasmid, a pUC18 plasmid, and the above-mentioned mer determinant as a selectable marker. Mercury ion-sensitive T. ferrooxidans strains were electroporated with constructed plasmids, and one strain, Y4-3 (of 30 independent strains tested), was found to have a transformation efficiency of 120 to 200 mercury-resistant colonies per microgram of plasmid DNA. This recipient strain was confirmed to be T. ferrooxidans by physiological, morphological, and chemotaxonomical data. The transformants carried a plasmid with no physical rearrangements through 25 passages under no selective pressure. Cell extracts showed mercury ion-dependent NADPH oxidation activity. 相似文献
3.
Ontogeny of surfactant apoprotein D, SP-D, in the rat lung 总被引:1,自引:0,他引:1
Y Ogasawara Y Kuroki M Shiratori H Shimizu K Miyamura T Akino 《Biochimica et biophysica acta》1991,1083(3):252-256
Surfactant protein D (SP-D) is a collagenous surfactant-associated glycoprotein synthesized by alveolar type II cells. Antiserum against rat SP-D was raised in rabbits and an enzyme-linked immunosorbant assay (ELISA) has been developed using anti-rat SP-D IgG. In the present study we examined the developmental profile of SP-D in the rat lung compared with that of surfactant protein A (SP-A). SP-A content in the lungs increased during late gestation and reached its maximum on day 1 of neonate, and then gradually decreased until at least day 5. SP-D content during early gestation was less than 10 ng/mg protein until day 18, but on day 19 there was a 4-fold increase in SP-D (compared to that on day 18). It increased twice between day 21 and the day of birth, when it reached the adult level of 250 ng/mg protein, which is about one fourth that of the adult level of SP-A. Unlike SP-A there seemed to be no decrease in SP-D content after birth. These results demonstrate that SP-D is regulated developmentally as are the other components of surfactant, but the inconsistency in the developmental profiles of SP-A and SP-D suggests that these proteins may play different roles in lung maturation. 相似文献
4.
Nomura M Katayama K Nishimura A Ishida Y Ohta S Komari T Miyao-Tokutomi M Tajima S Matsuoka M 《Plant molecular biology》2000,44(1):99-106
The small subunit of ribulose-bisphosphate carboxylase (Rubisco), encoded by rbcS, is essential for photosynthesis in both C3 and C4 plants, even though the cell specificity of rbcS expression is different between C3 and C4 plants. The C3 rbcS is specifically expressed in mesophyll cells, while the C4 rbcS is expressed in bundle sheath cells, and not mesophyll cells. Two chimeric genes were constructed consisting of the structural gene encoding -glucuronidase (GUS) controlled by the two promoters from maize (C4) and rice (C3) rbcS genes. These constructs were introduced into a C4 plant, maize. Both chimeric genes were specifically expressed in photosynthetic organs, such as leaf blade, but not in non-photosynthetic organs. The expressions of the genes were also regulated by light. However, the rice promoter drove the GUS activity mainly in mesophyll cells and relatively low in bundle sheath cells, while the maize rbcS promoter induced the activity specifically in bundle sheath cells. These results suggest that the rice promoter contains some cis-acting elements responding in an organ-pecific and light-inducible regulation manner in maize but does not contain element(s) for bundle sheath cell-specific expression, while the maize promoter does contain such element(s). Based on this result, we discuss the similarities and differences between the rice (C3) and maize (C4) rbcS promoter in terms of the evolution of the C4 photosynthetic gene. 相似文献
5.
Miura T Fukami TA Hasegawa K Ono N Suda A Shindo H Yoon DO Kim SJ Na YJ Aoki Y Shimma N Tsukuda T Shiratori Y 《Bioorganic & medicinal chemistry letters》2011,21(19):5778-5783
Heat shock protein 90 (Hsp90) is a molecular chaperone which regulates maturation and stabilization of its substrate proteins, known as client proteins. Many client proteins of Hsp90 are involved in tumor progression and survival and therefore Hsp90 can be a good target for developing anticancer drugs. With the aim of efficiently identifying a new class of orally available inhibitors of the ATP binding site of this protein, we conducted fragment screening and virtual screening in parallel against Hsp90. This approach quickly identified 2-aminotriazine and 2-aminopyrimidine derivatives as specific ligands to Hsp90 with high ligand efficiency. In silico evaluation of the 3D X-ray Hsp90 complex structures of the identified hits allowed us to promptly design CH5015765, which showed high affinity for Hsp90 and antitumor activity in human cancer xenograft mouse models. 相似文献
6.
Togi S Ikeda O Kamitani S Nakasuji M Sekine Y Muromoto R Nanbo A Oritani K Kawai T Akira S Matsuda T 《The Journal of biological chemistry》2011,286(21):19170-19177
7.
Yasuhiro Iwao Chihiro Kimoto Ayaka Fujimoto Asuka Suda Yuki Hara 《Molecular reproduction and development》2020,87(3):358-369
The union between a sperm and an egg nucleus in egg fertilization is necessary to mix genetic materials to create a new diploid genome for the next generation. In most animals, only one sperm is incorporated into the egg (monospermy), but several animals exhibit physiological polyspermy in which several sperms enter the egg during normal fertilization. However, only one sperm nucleus forms the zygote nucleus with the egg nucleus, even in a polyspermic egg. The cellular and molecular mechanisms involved in the selection of sperm nuclei in the egg cytoplasm have been well investigated in urodele amphibians. The principal sperm nucleus develops a larger sperm aster and contacts the egg nucleus to form a zygote nucleus, whereas other accessory sperm nuclei are unable to approach the egg nucleus. The diploid zygote nucleus induces cleavage and participates in embryonic development, whereas the accessory sperm nuclei undergo pyknosis and degenerate. We propose several models to account for the mechanisms of the selection of one sperm nucleus and the degeneration of accessory sperm nuclei. The roles of physiological polyspermy in animal reproduction are discussed by comparison with other polyspermic species. 相似文献
8.
Gilman Eric Chaloupka Milani Ishizaki Asuka Carnes Mathew Naholowaa Hollyann Brady Colby Ellgen Sarah Kingma Eric 《Reviews in Fish Biology and Fisheries》2021,31(3):653-666
Reviews in Fish Biology and Fisheries - Albatross bycatch has been increasing over the past decade in the US tuna longline fishery of the central North Pacific. A controlled field... 相似文献
9.
Susumu Hara Shigeki Arawaka Hiroyasu Sato Youhei Machiya Can Cui Asuka Sasaki Shingo Koyama Takeo Kato 《Molecular biology of the cell》2013,24(11):1649-1660
Most α-synuclein (α-syn) deposited in Lewy bodies, the pathological hallmark of Parkinson disease (PD), is phosphorylated at Ser-129. However, the physiological and pathological roles of this modification are unclear. Here we investigate the effects of Ser-129 phosphorylation on dopamine (DA) uptake in dopaminergic SH-SY5Y cells expressing α-syn. Subcellular fractionation of small interfering RNA (siRNA)–treated cells shows that G protein–coupled receptor kinase 3 (GRK3), GRK5, GRK6, and casein kinase 2 (CK2) contribute to Ser-129 phosphorylation of membrane-associated α-syn, whereas cytosolic α-syn is phosphorylated exclusively by CK2. Expression of wild-type α-syn increases DA uptake, and this effect is diminished by introducing the S129A mutation into α-syn. However, wild-type and S129A α-syn equally increase the cell surface expression of dopamine transporter (DAT) in SH-SY5Y cells and nonneuronal HEK293 cells. In addition, siRNA-mediated knockdown of GRK5 or GRK6 significantly attenuates DA uptake without altering DAT cell surface expression, whereas knockdown of CK2 has no effect on uptake. Taken together, our results demonstrate that membrane-associated α-syn enhances DA uptake capacity of DAT by GRKs-mediated Ser-129 phosphorylation, suggesting that α-syn modulates intracellular DA levels with no functional redundancy in Ser-129 phosphorylation between GRKs and CK2. 相似文献
10.
Sayuri Hamano Atsushi Tomokiyo Daigaku Hasegawa Asuka Yuda Hideki Sugii Shinichiro Yoshida Hiromi Mitarai Naohisa Wada Hidefumi Maeda 《Journal of cellular biochemistry》2020,121(12):4798-4808
Adrenergic receptors (ARs) are receptors of noradrenalin and adrenalin, of which there are nine different subtypes. In particular, β2 adrenergic receptor (β2-AR) is known to be related to the restoration and maintenance of homeostasis in bone and cardiac tissues; however, the functional role of signaling through β2-AR in periodontal ligament (PDL) tissue has not been fully examined. In this report, we investigated that β2-AR expression in PDL tissues and their features in PDL cells. β2-AR expressed in rat PDL tissues and human PDL cells (HPDLCs) derived from two different patients (HPDLCs-2G and -3S). Rat PDL tissue with occlusal loading showed high β2-AR expression, while its expression was downregulated in that without loading. In HPDLCs, β2-AR expression was increased exposed to stretch loading. The gene expression of PDL-related molecules was investigated in PDL clone cells (2-23 cells) overexpressing β2-AR. Their gene expression and intracellular cyclic adenosine monophosphate (cAMP) levels were also investigated in HPDLCs treated with a specific β2-AR agonist, fenoterol (FEN). Overexpression of β2-AR significantly promoted the gene expression of PDL-related molecules in 2 to 23 cells. FEN led to an upregulation in the expression of PDL-related molecules and increased intracellular cAMP levels in HPDLCs. In both HPDLCs, inhibition of cAMP signaling by using protein kinase A inhibitor suppressed the FEN-induced gene expression of α-smooth muscle actin. Our findings suggest that the occlusal force is important for β2-AR expression in PDL tissue and β2-AR is involved in fibroblastic differentiation and collagen synthesis of PDL cells. The signaling through β2-AR might be important for restoration and homeostasis of PDL tissue. 相似文献