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51.
Kawahara M Obata Y Sotomaru Y Shimozawa N Bao S Tsukadaira T Fukuda A Kono T 《Nature protocols》2008,3(2):197-209
A reliable nuclear transfer method was first reported in 1983; it provided definite evidence that parthenogenetic embryos are lethal at early postimplantation in mammals. Subsequently, nuclear transfer has been extensively used as an important and versatile tool for investigating embryo and somatic-cell cloning and nucleo-cytoplasmic interactions. Further development of this technique has enabled the generation of bimaternal embryos containing two haploid sets of maternal genomes from female germ cells of different origins. By using a 2-d nuclear transfer system for oocyte reconstruction, viable mice can be produced solely from maternal genomes, without the participation of the paternal genome. This oocyte reconstruction system, as described in this protocol, could provide valuable guidelines for exploring the potential endowments of gametes and for conferring novel properties to them. 相似文献
52.
53.
Cartilage link protein interacts with neurocan, which shows hyaluronan binding characteristics different from CD44 and TSG-6 总被引:2,自引:0,他引:2
Uwe Rauch Satoshi Hirakawa Toshitaka Oohashi Joachim Kappler Gunnel Roos 《Matrix biology》2004,22(8):221-639
The interaction of neurocan with hyaluronan was qualitatively characterized with alkaline phosphatase fusion proteins secreted by mammalian cells. The wild type neurocan hyaluronan binding domain fused to alkaline phosphatase bound to immobilized hyaluronan under physiological as well as moderately hypertonic conditions, whereas its ability to bind to immobilized chondroitin sulfate dropped rapidly with increasing salt concentration. Strong hyaluronan binding ability was still evident when in both link modules within the hyaluronan binding domain a basic amino acid was mutated, which is well conserved among link modules of hyaluronan binding proteins. A strong enhancement of the binding of neurocan to immobilized hyaluronan was observed after preincubation of the immobilized hyaluronan with cartilage link protein. Moreover, this preincubation mediated also the binding of a fusion protein representing only the immunoglobulin module of neurocan linked to alkaline phosphatase, which showed no binding to immobilized hyaluronan alone. The interaction of the neurocan immunoglobulin module with link protein could also be shown by overlay blot analysis. These observations suggest that the hyaluronan binding characteristics of paired link modules are different from those of single link modules, and that the reported temporal co-expression of cartilage link protein and of neurocan in developing brain implicates the possibility of a cooperative function of these molecules. 相似文献
54.
Itoh Hiroya Miura Ai Matsui Makoto Arazoe Takayuki Nishida Keiji Kumagai Toshitaka Arita Masanori Tamano Koichi Machida Masayuki Shibata Takashi 《Applied microbiology and biotechnology》2018,102(3):1393-1405
Applied Microbiology and Biotechnology - In the production of useful microbial secondary metabolites, the breeding of strains is generally performed by random mutagenesis. However, because random... 相似文献
55.
There have been no reports of infanticide in wild gelada baboons and it has been argued that infanticide is not necessary
in geladas, since the birth interval of female gelada can be shortened after takeover of a unit by a new leader male without
infanticide. However, we observed an instance of infanticide in a newly-found wild gelada population in the Arsi Region of
Ethiopia.
After a leader male of the unit was severely wounded by a leopard attack, he was quite weakened. The second male of the unit,
a young adult male, became the leader of the unit three weeks later, but the former leader continued to stay in the unit as
a second male. After a week, two other adult males joined the unit which, therefore, came to include four adult males. The
infanticide took place nine days later. The perpetrator was one of the immigrant males and he showed great interest in the
mother of the unweaned victim infant. Although the perpetrator copulated with her after the infanticide, the usurper was found
to own all three adult females after two weeks following the infanticide; i.e. the perpetrator could not own any female. The
wounded former leader showed conspicuous protective behavior towards the victim's mother and the dead infant.
One possible explanation for the occurrence of infanticide in this population of geladas is as follows. Gelada males in this
area may be able to join units more easily to form multi-male units but then have shorter tenure in the units. Facing the
unstable condition of units, they may sometimes engage in infanticide to increase their breeding opportunities, even before
becoming a leader. 相似文献
56.
SAD‐B kinase regulates pre‐synaptic vesicular dynamics at hippocampal Schaffer collateral synapses and affects contextual fear memory 下载免费PDF全文
57.
Akio Mori Toshitaka Iwamoto Umeyo Mori Afework Bekele 《Primates; journal of primatology》1999,40(2):365-381
A new population of gelada baboons isolated from other known gelada populations living on the opposite side of the Rift Valley
was found in 1989 in the Arsi region of Ethiopia (Mori &Belay, 1990). Subsequent observations were conducted on the new gelada population in three study periods of 16 to 55 days over
three consecutive years, 1994–1996. When we compare this population with other well studied northern populations, densities
were lower, band size was smaller and the ratio of juveniles to adult females was lower. Based onOhsawa andDunbar's (1984) criteria these results suggest that this population exploits the harshest environment among known gelada populations.
This may be due to the severe effect of the dry season at low altitude in the study site. Band size was small in the study
site. Association rates of units were low, and each unit behaved more independently than those of northern populations. Age-sex
composition of units changed drastically between consecutive study periods, indicating unstable unit structure. Moreover,
there seems to be a tendency in this population whereby several adult males easily invade and are incorporated into a unit
but the unit is expected to thereafter divide. The phenomenon can be explained by two factors: (1) Each unit fed rather independently
in this area, where units fed intensively on both plateau and the slope of the cliff; and (2) Males may be incorporated in
a unit for defense against leopards. As the units were vary small in size and unstable as compared with the Semien gelada
units, the traditional concept of a stable gelada unit formed by blood related females, does not seem to fit this population. 相似文献
58.
The mechanism of infection by Vibrio sp. P11 promoting the ice-ice disease in Kappaphycus alvarezii was investigated in vitro.
Its intensity of infection differs from that of another ice-ice promoter (Cytophaga sp. P25) by promoting the disease much
faster. However, when secondary infection by other bacteria starts, its ability to compete with these bacteria gradually diminishes,
whereas, infection by P25, although not displaying such drastic effects as P11, shows consistent competitive ability against
other bacteria. Time-series infection experiments with application of polyclonal antibodies to specifically detect Vibrio
sp. P11 revealed that this bacterium has a high affinity for the seaweed especially when the latter is stressed. It promotes
the disease after a rapid increase in cell density of up to 107 g−1 (wet wt.) in the first 24 h. This bacterial cell build-up may take only 1–2 h on stressed thalli, but takes about 24 h on
non-stressed thalli. Build-up is not sustainable in non-stressed thalli as high density is usually followed by a sudden decline
in cell number believed to result from an algal defence against potential pathogens. Inoculation of the bacterium on thalli
incubated in continuous culture system extends the time of bacterial attachment due to laminar flow and, possibly, competition
by existing bacteria on the seaweed surface and in ambient seawater medium. Motility-driven cell attachment by this bacterium
is suggested as an important factor for infection.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
59.
Effects of lactoferrin and lactoperoxidase‐containing food on the oral microbiota of older individuals 下载免费PDF全文
Manabu Nakano Hiroyuki Wakabayashi Hirosuke Sugahara Toshitaka Odamaki Koji Yamauchi Fumiaki Abe Jin‐Zhong Xiao Kohji Murakami Kentaro Ishikawa Shouji Hironaka 《Microbiology and immunology》2017,61(10):416-426
60.
Toshio Takahashi Osamu Koizumi Eisuke Hayakawa Sumiko Minobe Rinako Suetsugu Yoshitaka Kobayakawa Thomas C. G. Bosch Charles N. David Toshitaka Fujisawa 《Development genes and evolution》2009,219(3):119-129
From an evolutionary point of view, Hydra has one of the most primitive nervous systems among metazoans. Two different groups of peptides that affect neuron differentiation
were identified in a systematic screening of peptide signaling molecules in Hydra. Within the first group of peptides, a neuropeptide, Hym-355, was previously shown to positively regulate neuron differentiation.
The second group of peptides encompasses the PW family of peptides that negatively regulate neuron differentiation. In this
study, we identified the gene encoding PW peptide preprohormone. Moreover, we made the antibody that specifically recognizes
LPW. In situ hybridization and immunohistochemical analyses showed that the PW peptides and the gene encoding them were expressed
in ectodermal epithelial cells throughout the body except for the basal disk. The PW peptides are produced by epithelial cells
and are therefore termed “epitheliopeptides.” Together with Hym-355, the PW family peptides mediate communication between
neurons and epithelial cells and thereby maintain a specific density of neurons in Hydra.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Toshio Takahashi, Osamu Koizumi equally contributed to this study. 相似文献