全文获取类型
收费全文 | 513篇 |
免费 | 26篇 |
专业分类
539篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 13篇 |
2015年 | 21篇 |
2014年 | 22篇 |
2013年 | 31篇 |
2012年 | 17篇 |
2011年 | 22篇 |
2010年 | 18篇 |
2009年 | 11篇 |
2008年 | 46篇 |
2007年 | 37篇 |
2006年 | 33篇 |
2005年 | 37篇 |
2004年 | 26篇 |
2003年 | 23篇 |
2002年 | 23篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1974年 | 2篇 |
1970年 | 2篇 |
1962年 | 1篇 |
1957年 | 1篇 |
1953年 | 1篇 |
1951年 | 2篇 |
1939年 | 1篇 |
排序方式: 共有539条查询结果,搜索用时 0 毫秒
1.
K. Karasawa 《Genetica》1962,32(1):165-169
Summary Karyological observations were made in fourteenCrocus including various Linnean species and garden varieties.C. biflorus Weldenii albus was an autotetraploid with five tetravalents,C. nudiflorus being also an autotetraploid having eleven tetravalents.The expenses of this study were partly defrayed by a grant from the Ministry of Education, to which I wish to express my cordial thanks. 相似文献
2.
Shinji Yamasaki Zaw Lin Hiromasa Shirai Akito Terai Yuichi Oku Hideaki Ito Mari Ohmura Tadahiro Karasawa Teizo Tsukamoto Hisao Kurazono Yoshifumi Takeda 《Microbiology and immunology》1996,40(5):345-352
To identify the type of Verotoxins (VT) produced by Verocytotoxin-producing Escherichia coli (VTEC), a sensitive bead-enzyme-linked immunosorbent assay and polymerase chain reaction with common and specific primers to various VTs (VT1, VT2, VT2vha, VT2vhb, and VT2vp1) were developed. Together with colony hybridization tests with oligo- and polynucleotide probes, these methods were applied to VTEC isolates to type the VT produced. The toxin types of 26 of 37 strains were identified, but the reaction profiles in assays of the remaining 11 strains suggested the existence of new VT2 variants. The application of these identification procedures may be useful as a tool for clinical and epidemiological studies of VTEC infection. 相似文献
3.
Measuring the ratio of the number of photooriented chloroplaststo the total number of chloroplasts, we found that photoorientationof chloroplasts in protonemata of the fern Adiantum capillus-veneriscould be induced by brief irradiation with polarized red light.After irradiation with red light (R) of 3 or 10 min, orientationalmovement was detected as early as 10 min after the irradiation;it continued during the subsequent dark period for 3060min, after which chloroplasts gradually dispersed again. WhenR-treated protonemata were irradiated briefly with a second10-min pulse of R, 60 min after the onset of the first irradiation,the orientational response of chloroplasts was again observed.Typical red/far-red photoreversibility was apparent in the response,indicating the involvement of phytochrome. By contrast, irradiationwith polarized blue light for 10 min was ineffective, whileirradiation with blue light (B) at the same fluence for a longerperiod of time clearly induced the photoorientation of chloroplasts.It is likely that longterm irradiation is necessary for theresponse mediated by a blue-light receptor. When protonemata were irradiated with far-red light (FR) immediatelyafter R or after a subsequent dark period of 10 min, the magnitudeof the orientational response was smaller and chloroplasts dispersedmore quickly than those exposed to R alone. When FR was appliedat 50 min, when the response to R had reached the maximum level,chloroplasts again dispersed rapidly to their dark positions.These results indicate that PFR not only induces the photoorientationmovement of chloroplasts but also fixes the chloroplasts atthe sites to which they have moved as a result of photoorientation. (Received June 2, 1993; Accepted January 11, 1994) 相似文献
4.
Karasawa Takusato; Tabuchi Kouji; Fumoto Masaki; Yasukawa Tamio 《Bioinformatics (Oxford, England)》1993,9(3):243-251
A model system is proposed to simulate the folding processesof proteins during thermal annealing. This system consists offour subsystems: (i) the pearl necklace model with isotropicinter-residue interactions; (ii) the extended pearl necklacemodel with anisotropic interaction potentials; (iii) moltenglobule phase dynamics; and (iv) final generation of the three-dimensionalstructure of a given protein. In this paper results obtainedwith the pearl necklace model are reported. This model consistsof spherical elements and virtual bonds of 3.8 Å in lengthand is intended to sinudate dynamical processes at relativelyhigh temperature where entropic terms play a dominant role.Inter-residue interactions are composed of spherical soft repulsivepotentials and hydrophobic interactions inherent to respectiveresidues. A simulation of folding processes of BPTI startingfrom the fully extended conformation indicated that intermediates,even at early stages of folding, are not randomly coiled butassume organized structures that resemble, to some extent, thenative conformation. 相似文献
5.
Prevention of PERV infections in pig to human xenotransplantation by the RNA interference silences gene 总被引:6,自引:0,他引:6
Miyagawa S Nakatsu S Nakagawa T Kondo A Matsunami K Hazama K Yamada J Tomonaga K Miyazawa T Shirakura R 《Journal of biochemistry》2005,137(4):503-508
The possibility of preventing the transmission of porcine endogenous retrovirus (PERV) to human cells using short interfering RNAs (siRNA) was investigated. The siRNA for the p30 of PERV gag region was cloned into pSUPER, the polymerase-III H1-RNA gene promoter. A green fluorescence protein (GFP) was also cloned into pSUPER to establish pSXGH. Pig endothelial cells (PEC) were transduced with the LacZ gene by pseudotype infection, and infected with PERV subtype B, resulting in the formation of PEC(LacZ)/PB. The PEC(LacZ)/PB was next transfected with pSXGH-siRNA. The expression of siRNA was provisionally checked by determining the level of expression of GFP. Culture supernatants of infected cells were then inoculated into HEK293 cells. The siRNA clearly destroyed the PERV infectivity of PEC(LacZ)/PB in both transient cell lines and stable clones. Moreover, the decreased levels of mRNA and gag protein were evidenced in the stable clones by real-time PCR and Western blotting, respectively. The final goal of our study was to establish a transgenic pig expressing the siRNA for PERV. The results suggest that siRNA represents a novel approach for controlling PERV infections in clinical xenotransplantation. 相似文献
6.
7.
Akira Kai Hiroko Karasawa Masayuki Kikawa Kenichi Hatanaka Kei Matsuzaki Tohru Mimura Yutaro Kaneko 《Carbohydrate polymers》1998,35(3-4):271-278
Biosynthesis of branched glucan by Pestalotiopsis from media containing D-(1-13C)glucose, D-(2-13C)glucose, D-(4-13C)glucose, D-(6-13C)glucose or a mixture of D-(1-13C)glucose and D-(2-13C)glucose was carried out to elucidate biosynthetic mechanism of branched polysaccharides. 13C NMR spectra of the labeled polysaccharides were determined and assigned. Analysis of 13C NMR spectra of glucitol acetates obtained from hydrolysates of the labeled branched polysaccharides indicated that transfer of labeling from C-1 to C-3 and C-6 carbons, from C-2 to C-1, C-3 and C-5 carbons, and from C-6 to C-1 carbon. From the results the percentages of routes via which the polysaccharide is biosynthesized are estimated. They show that the biosynthesis of the polysaccharide via the Embden-Meyerhof pathway and that from lipids and proteins are more active, and the pentose cycle is less active, than in the biosynthesis of cellulose and curdlan. As for the results, labeling at C-6 carbon in the branched polysaccharide cultured from D-(6-13C)glucose was low, compared to that of cellulose and curdlan. 相似文献
8.
Sleep and Biological Rhythms - 相似文献
9.
10.
Akikazu Hatanaka Tadahiko Kajiwara Takatoshi Koda 《Bioscience, biotechnology, and biochemistry》2013,77(10):2115-2117
The substrate specificity of enzyme system producing C6-aldehyde in Thea chloroplasts was clarified with an entire series of synthesized positional isomers, in which the position of cis-1, cis-4-pentadiene system varies from C-3 to C-13 in C18 fatty acid and geometrical isomers of linoleic acid. The structural requirement for the substrate of enzyme system producing C6-aldehyde is the presence of cis-1, cis-4-pentadiene system between ω-6 and ω-10. 相似文献