全文获取类型
收费全文 | 141篇 |
免费 | 3篇 |
国内免费 | 1篇 |
出版年
2022年 | 1篇 |
2018年 | 1篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 9篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有145条查询结果,搜索用时 15 毫秒
1.
Neomorph and leaf differentiation as alternative morphogenetic pathways in soybean tissue culture. 总被引:1,自引:0,他引:1
Somatic embryogenesis and organogenesis were induced on immature cotyledons of different soybean cultivars. The anatomical investigation of morphogenesis proved neomorph differentiation instead of somatic embryos, and leaf formation instead of shoot development. While normal embryos were induced in 0-3.1% of the explants, neomorphs developed at a much higher rate i.e. in 10.5-78.9% depending on the genotype. Likewise organogenesis preferably followed the pathway of leaflet development (3.1-26.3%) than that of shoot tip formation (0-2.6%). Low plant regeneration frequency of soybean can partly be explained with these two alternative abortive pathways of morphogenesis probably induced with higher frequency than the normal pathways by the generally used in vitro methods. 相似文献
2.
D. Q. Binh L. E. Heszky G. Gyulai E. Kiss A. Csillag 《Plant Cell, Tissue and Organ Culture》1989,18(2):195-200
Callus was induced from seeds of Puccinellia distans (L.) Parl. on MS medium supplemented with 2 mgl-1 2,4-dichlorophenoxyacetic acid and 0.5 mgl-1 kinetin. Morphogenesis initiation was achieved during subculture on medium containing 0.1 mgl-1 2,4-D. From the point of morphogenetic capacity, 3 types of callus were selected. High frequency of plant regeneration was obtained by selection of embryogenic type of callus, and culture on N6 medium and N6 medium supplemented with kinetin (5–10 mgl-1), or kinetin (2 mgl-1) and IAA (0.5 mgl-1). A high ratio of albinos among regenerants was observed. 相似文献
3.
Csillag A. Bourne R. C. Patel Sanjay N. Stewart Michael G. Tömböl Teréz 《Brain Cell Biology》1989,18(3):369-379
Brain Cell Biology - The distribution of GABA-like immunoreactivity (GABA-LI) in the ectostriatal core (Ec) of domestic chicks (one to two days old) was investigated using (1) preembedding GABA... 相似文献
4.
Do Quang Binh László E. Heszky Gabor Gyulai Anikó Csillag 《Plant Cell, Tissue and Organ Culture》1992,29(2):75-82
Cells of a 2-year-old suspension culture of rice (Oryza sativa L.), grown under 1.5% NaCl stress for 3 months, gave rise to plants through embryogenesis in different saline conditions. The high regeneration potential (59.6%) on salt-free medium decreased rapidly with increasing concentration of salt in the regeneration medium. At 1.25% NaCl, healthy shoots were developed in 14.9% of the cultures. Under 1.5% salt stress, embryo formation and embryo germination (6.1%) was observed but further development into plants was inhibited. Cells not pretreated with salt produced plants at a low frequency (2.6–4.2%) both in salt-free and low saline condition (0.75–1% NaCl). Cells pretreated for 3 months with 0.75% salt did not give rise to plants on all tested media. Plants regenerated from the salt-stressed cultures were transferred to soil and grew to maturity in a greenhouse.Abbreviations BA
6-benzyladenine
- CH
casein hydrolysate
- 2,4-D
2,4-dichlorophenoxyacetic acid
- NAA
1-naphthaleneacetic acid 相似文献
5.
Yves Alméras 《Geobios》1980,13(3):327-409
A lot of numerous rhynchonellid shells referedto the main species of genus SphenorhynchiaBuckman have been sampled in stratigraphically well-defined beds of Dogger period in the Mâconnais and in the Jura (France). Here, morphologic and anatomic characters and variability of S. plicatella, S. matisconensis, S. bugeysiaca, S. ferryi and S. dominula are studied.The main interest of this revision is to establish a complete diagnosis of the genus, not studied since its creation in 1918, with very limited knowledge of the internal structures. The settlement of this diagnosis is based on the type-species, S. plicatella, sometimes a little «unconventional form (beak, outline of the young shells, orientation of dental lamellae, delthyrial cavity), and also on the other species' characters. So, I expect that a later diagnosis will be avoided.Other advantages are observations on the taxonomic place of Sphenorhynchia in the RhynchonellidaeGray (in the TetrarhynchiinaeAger rather than in the CyclothyridinaeMakridin), on its evolution in the course of the Dogger period and the establishment of the biostratigraphy of its main species. 相似文献
6.
The configuration of brain mitochondria was compared in situ, after aldehyde perfusion and/or osmium immersion fixation and in isolated fractions of different functional performance. After combined aldehyde perfusion osmium immersion fixation in situ, mitochondria were condensed having a dark matrix. Fractions capable of controlled respiration also consisted of condensed mitochondria. On the contrary, expanded mitochondria with light matrix were brought about by immersion fixation. Fractions consisting predominantly of light mitochondria displayed no controlled respiration. Light matrix and expanded form are therefore regarded as a functionally impaired state of brain mitochondria. The condensed form is thought to be a landmark of good fixation. 相似文献
7.
Leiz M. C. Véras Vanessa R. R. Cunha Filipe C. D. A. Lima Maria A. Guimar?es Marianne M. Vieira Yuri D. M. Campelo Vanessa Y. Sakai David F. Lima Paulo S. Carvalho Jr Javier A. Ellena Paulo R. P. Silva Luciene C. Vasconcelos Markus Godejohann Helena M. Petrilli Vera R. L. Constantino Yvonne P. Mascarenhas José Roberto de Souza de Almeida Leite 《PloS one》2013,8(6)
This paper presents an industrial scale process for extraction, purification, and isolation of epiisopiloturine (EPI) (2(3H)-Furanone,dihydro-3-(hydroxyphenylmethyl)-4-[(1-methyl-1H-imidazol-4-yl)methyl]-, [3S-[3a(R*),4b]]), which is an alkaloid from jaborandi leaves (Pilocarpus microphyllus Stapf). Additionally for the first time a set of structural and spectroscopic techniques were used to characterize this alkaloid. EPI has shown schistomicidal activity against adults and young forms, as well as the reduction of the egg laying adult worms and low toxicity to mammalian cells (in vitro). At first, the extraction of EPI was done with toluene and methylene chloride to obtain a solution that was alkalinized with ammonium carbonate. The remaining solution was treated in sequence by acidification, filtration and alkalinization. These industrial procedures are necessary in order to remove impurities and subsequent application of the high performance liquid chromatography (HPLC). The HPLC was employed also to remove other alkaloids, to obtain EPI purity higher than 98%. The viability of the method was confirmed through HPLC and electrospray mass spectrometry, that yielded a pseudo molecular ion of m/z equal to 287.1 Da. EPI structure was characterized by single crystal X-ray diffraction (XRD), 1H and 13C nuclear magnetic resonance (NMR) in deuterated methanol/chloroform solution, vibrational spectroscopy and mass coupled thermal analyses. EPI molecule presents a parallel alignment of the benzene and the methyl imidazol ring separated by an interplanar spacing of 3.758 Å indicating a π-π bond interaction. The imidazole alkaloid melts at 225°C and decomposes above 230°C under air. EPI structure was used in theoretical Density Functional Theory calculations, considering the single crystal XRD data in order to simulate the NMR, infrared and Raman spectra of the molecule, and performs the signals attribution. 相似文献
8.
G.?A.?Velikodvorskaya L.?A.?Chekanovskaya N.?A.?LuninaEmail author O.?V.?Sergienko V.?G.?Lunin I.?A.?Dvortsov V.?V.?Zverlov 《Molecular Biology》2013,47(4):581-586
The nucleotide sequence of a chromosome fragment of the thermophilic anaerobic bacterium Caldicellulosiruptor bescii (syn. Anaerocellum thermophilum) has been determined. The fragment contains four open reading frames with the second encoding a 749 aa multimodular endo-1,4-β-glucanase CelD (85019 Da). The N-terminal region of the protein includes a signal peptide and a catalytic module of glycoside hydrolase family 5 (GH5), followed by a carbohydrate-binding module of family 28 (CBM28). The C-terminal region bears three SLH modules. The recombinant endoglucanase and its two separate modules, the catalytic module and CBM28, were produced in E. coli cells and purified to homogeneity. An analysis of the catalytic properties showed CelD to be an endo-1,4-β-glucanase with maximum activity on barley β-glucan at pH 6.2 and 70°C. The enzyme was stable at 50°C for 30 days. Upon removal of the C-terminal CBM28, the activity of GH5 was decreased on cellulose substrates, and its thermostability has dropped. Binding of CBM28 to amorphous cellulose has been almost irreversible as it could not be removed from this substrate in a range of pH of 4–11, temperatures of 0–75°C, and NaCl concentrations of 0–5 M. Only 100% formamide or 1% SDS have been able to remove the protein. 相似文献
9.
Manuel J. Steinbauer Richard Field John‐Arvid Grytnes Panayiotis Trigas Claudine Ah‐Peng Fabio Attorre H. John B. Birks Paulo A. V. Borges Pedro Cardoso Chang‐Hung Chou Michele De Sanctis Miguel M. de Sequeira Maria C. Duarte Rui B. Elias José María Fernández‐Palacios Rosalina Gabriel Roy E. Gereau Rosemary G. Gillespie Josef Greimler David E. V. Harter Tsurng‐Juhn Huang Severin D. H. Irl Daniel Jeanmonod Anke Jentsch Alistair S. Jump Christoph Kueffer Sandra Nogué Rüdiger Otto Jonathan Price Maria M. Romeiras Dominique Strasberg Tod Stuessy Jens‐Christian Svenning Ole R. Vetaas Carl Beierkuhnlein 《Global Ecology and Biogeography》2016,25(9):1097-1107
10.
Renata?A.?ZvyagilskayaEmail author Olga?A.?Parkhomenko Anna?V.?Gordeeva Yuliya?I.?Deryabina Bengt?L.?Persson 《Bioscience reports》2004,24(2):117-125
Energy status of the novel alkalitolerant Yarrowia lipolytica yeast strain grown at alkaline conditions (pH 9.7) was examined. Cells grown under such severe conditions were found to preserve high respiratory activity. The oxidative phosphorylation system dominated in the energy budget of the cell. A procedure was specially design to isolate tightly coupled mitochondria from yeast cells grown at alkaline conditions. The isolated mitochondrial preparations met known criteria of physiological intactness, as inferred from their ability to maintain distinctive state 4–3 respiration transition upon addition of ADP, high respiratory rates, good respiratory control values, and ADP/O ratios close to the theoretically expected maxima for the substrates used. 相似文献