全文获取类型
收费全文 | 2069篇 |
免费 | 111篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 25篇 |
2020年 | 12篇 |
2019年 | 23篇 |
2018年 | 27篇 |
2017年 | 24篇 |
2016年 | 50篇 |
2015年 | 74篇 |
2014年 | 86篇 |
2013年 | 115篇 |
2012年 | 159篇 |
2011年 | 157篇 |
2010年 | 87篇 |
2009年 | 83篇 |
2008年 | 136篇 |
2007年 | 178篇 |
2006年 | 134篇 |
2005年 | 152篇 |
2004年 | 140篇 |
2003年 | 132篇 |
2002年 | 131篇 |
2001年 | 22篇 |
2000年 | 24篇 |
1999年 | 25篇 |
1998年 | 22篇 |
1997年 | 14篇 |
1996年 | 10篇 |
1995年 | 17篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 16篇 |
1991年 | 16篇 |
1990年 | 7篇 |
1989年 | 13篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有2180条查询结果,搜索用时 15 毫秒
61.
Naoko Takeuchi 《Ichthyological Research》2009,56(1):18-27
Foraging behaviors of the piscivorous cornetfish Fistularia commersonii were observed at shallow reefs in Kuchierabu-jima Island, southern Japan. This fish foraged on two types of prey fishes:
one was reef fish that typically dwell on or near substrata (e.g., Tripterygiidae and Labridae), and the other was pelagic
fish that shoal in the water column (e.g., Clupeidae and Carangidae). The prey sizes, prey types and foraging behaviors changed
as the predator size increased. Prey sizes were largely limited by gape size of the cornetfish, and small predators consumed
small prey. The small cornetfish (10–30 cm in total length) fed only on reef fish captured after stalking (where the fish
slowly approaches the prey and then suddenly attacks). The stalking was done either solitarily or in foraging association
with conspecifics. Large fish (30–120 cm) fed on both types of fishes by stalking and/or chasing (where the fish chases the
prey using its high mobility and attacks), either solitarily or in foraging association with con- or heterospecifics. Thus,
chasing was only performed by the large cornetfish against pelagic prey fish in associative foraging with other con- and heterospecific
predators. As their body sizes increased, F. commersonii began to show a diversification of foraging behaviors, which was strongly related not only to the habitat types and anti-predatory
behaviors of the prey fishes but also to associative foraging with con- or heterospecifics, which improves their foraging
success. 相似文献
62.
63.
Caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine) are purine alkaloids that are present in high concentrations
in plants of some species of Camellia. However, most members of the genus Camellia contain no purine alkaloids. Tracer experiments using [8-14C]adenine and [8-14C]theobromine showed that the purine alkaloid pathway is not fully functional in leaves of purine alkaloid-free species. In
five species of purine alkaloid-free Camellia plants, sufficient evidence was obtained to show the occurrence of genes that are homologous to caffeine synthase. Recombinant
enzymes derived from purine alkaloid-free species showed only theobromine synthase activity. Unlike the caffeine synthase
gene, these genes were expressed more strongly in mature tissue than in young tissue.
The nucleotide sequence data reported here have been deposited in the GenBank database under the accession numbers AB297451
(CjCS1), AB362882 (CgCS1), AB362883 (CgCS2), AB362884 (CkCS1), AB362885 (ClCS1), and AB362886 (CcCS2). 相似文献
64.
Ayako Fukunaka Tomoyuki Suzuki Yayoi Kurokawa Tomohiro Yamazaki Naoko Fujiwara Kaori Ishihara Hitoshi Migaki Katsuzumi Okumura Seiji Masuda Yuko Yamaguchi-Iwai Masaya Nagao Taiho Kambe 《The Journal of biological chemistry》2009,284(45):30798-30806
The majority of CDF/ZnT zinc transporters form homo-oligomers. However, ZnT5, ZnT6, and their orthologues form hetero-oligomers in the early secretory pathway where they load zinc onto zinc-requiring enzymes and maintain secretory pathway functions. The details of this hetero-oligomerization remain to be elucidated, and much more is known about homo-oligomerization that occurs in other CDF/ZnT family proteins. Here, we addressed this issue using co-immunoprecipitation experiments, mutagenesis, and chimera studies of hZnT5 and hZnT6 in chicken DT40 cells deficient in ZnT5, ZnT6, and ZnT7 proteins. We found that hZnT5 and hZnT6 combine to form heterodimers but do not form complexes larger than heterodimers. Mutagenesis of hZnT6 indicated that the sites present in transmembrane domains II and V in which many CDF/ZnT proteins have conserved hydrophilic amino acid residues are not involved in zinc binding of hZnT6, although they are required for zinc transport in other CDF/ZnT family homo-oligomers. We also found that the long N-terminal half of hZnT5 is not necessary for its functional interaction with hZnT6, whereas the cytosolic C-terminal tail of hZnT5 is important in determining hZnT6 as a partner molecule for heterodimer formation. In DT40 cells, cZnT5 variant lacking the N-terminal half was endogenously induced during periods of endoplasmic reticulum stress and so seemed to function to supply zinc to zinc-requiring enzymes under these conditions. The results outlined here provide new information about the mechanism of action through heterodimerization of CDF/ZnT proteins that function in the early secretory pathway. 相似文献
65.
Saori Hata Sayaka Fujishige Yoichi Araki Naoko Kato Masahiko Araseki Masaki Nishimura Dieter Hartmann Paul Saftig Falk Fahrenholz Miyako Taniguchi Katsuya Urakami Hiroyasu Akatsu Ralph N. Martins Kazuo Yamamoto Masahiro Maeda Tohru Yamamoto Tadashi Nakaya Sam Gandy Toshiharu Suzuki 《The Journal of biological chemistry》2009,284(52):36024-36033
Alcadeins (Alcs) constitute a family of neuronal type I membrane proteins, designated Alcα, Alcβ, and Alcγ. The Alcs express in neurons dominantly and largely colocalize with the Alzheimer amyloid precursor protein (APP) in the brain. Alcs and APP show an identical function as a cargo receptor of kinesin-1. Moreover, proteolytic processing of Alc proteins appears highly similar to that of APP. We found that APP α-secretases ADAM 10 and ADAM 17 primarily cleave Alc proteins and trigger the subsequent secondary intramembranous cleavage of Alc C-terminal fragments by a presenilin-dependent γ-secretase complex, thereby generating “APP p3-like” and non-aggregative Alc peptides (p3-Alcs). We determined the complete amino acid sequence of p3-Alcα, p3-Alcβ, and p3-Alcγ, whose major species comprise 35, 37, and 31 amino acids, respectively, in human cerebrospinal fluid. We demonstrate here that variant p3-Alc C termini are modulated by FAD-linked presenilin 1 mutations increasing minor β-amyloid species Aβ42, and these mutations alter the level of minor p3-Alc species. However, the magnitudes of C-terminal alteration of p3-Alcα, p3-Alcβ, and p3-Alcγ were not equivalent, suggesting that one type of γ-secretase dysfunction does not appear in the phenotype equivalently in the cleavage of type I membrane proteins. Because these C-terminal alterations are detectable in human cerebrospinal fluid, the use of a substrate panel, including Alcs and APP, may be effective to detect γ-secretase dysfunction in the prepathogenic state of Alzheimer disease subjects. 相似文献
66.
67.
68.
Abstract. We investigated the seasonal prevalence of reproductive activities and of the development of brooded propagules in an intertidal sea anemone, Anthopleura sp., on the rocky shore of Mutsu Bay, in northern Japan. A monthly examination of anemones, by dissection and histological techniques, revealed no sign of gonad development, but did reveal that they produce and internally brood propagules throughout the year. Release of propagules was observed in the field. This anemone population appears to be entirely asexual and agametic, and may persist solely through clonal propagation. 相似文献
69.
Kazumi Yagasaki Naoko Morisaki Yoshiro Kitahara Atsuhito Miura Ryuhei Funabiki 《Cytotechnology》2003,43(1-3):97-103
Effects of leucine and related compounds on protein synthesis were studied in L6 myotubes. The incorporation of [3H]tyrosine into cellular protein was measured as an index of protein synthesis. In leucine-depleted L6 myotubes, leucine and its keto acid, α-ketoisocaproic acid (KIC), stimulated protein synthesis, while D-leucine did not. Mepacrine, an inhibitor of both phospholipases A2 and C, canceled stimulatory actions of L-leucine and KIC on protein synthesis. Neither indomethacin, an inhibitor of cyclooxygenase, nor caffeic acid, an inhibitor of lipoxygenase, diminished their stimulatory actions, suggesting no involvement of arachidonic acid metabolism. Conversely, 1-O-hexadecyl-2-O-methylglycerol, an inhibitor of proteinkinase C, significantly canceled the stimulatory actions of L-leucine and KIC on protein synthesis, suggesting an involvement of phosphatidylinositol degradation and activation of protein kinase C. L-Leucine caused a rapid activation of protein kinase C in both cytosol and membrane fractions of the cells. These results strongly suggest that both L-leucine and KIC stimulate protein synthesis in L6 myotubes through activation of phospholipase C and protein kinase C. 相似文献
70.
Hitoshi Sashiwa Shizu Fujishima Naoko Yamano Norioki Kawasaki Atsuyoshi Nakayama Einosuke Muraki Mongkol Sukwattanasinitt Rath Pichyangkura andSei-ichi Aiba 《Carbohydrate polymers》2003,51(4):391-395
N-Acetyl-
-glucosamine (GlcNAc) was produced from chitin by use of crude enzyme preparations. The efficient production of GlcNAc by cellulases derived from Trichoderma viride (T) and Acremonium cellulolyticus (A) was observed by HPLC analysis compared to lipase, hemicellulase, and pectinase. β-Chitin showed higher degradability than α-chitin when using cellulase T. The optimum pH of cellulase T was 4.0 on the hydrolysis of β-chitin. The yield of GlcNAc was enhanced by mixing of cellulase T and A. 相似文献