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91.
Intracellular pH and Proton-Transport in Barley Root Cells under Salt Stress: in Vivo 31P-NMR Study 总被引:1,自引:0,他引:1
Katsuhara Maki; Yazaki Yoshiaki; Sakano Katsuhiro; Kawasaki Toshio 《Plant & cell physiology》1997,38(2):155-160
Salt stress-induced changes of intracellular pH and in levelsof phosphorous compounds were monitored in intact root tipsof barley seedlings (Hordeum vulgare cv. Akashin-riki) by invivo 31P-nuclear magnetic resonance (NMR) spectroscopy. Vacuolaralkalization was observed after treatment with both 300 and500 mM NaCl. Much of the observed apparent alkalization of thecytoplasm was eliminated when the effect of Na+ ions on thetitration curve was considered. Within 1 h after the initiationof salt stress, levels of glucose-6-phosphate and UDP-glucosedecreased markedly, and such decreases might lead directly orindirectly to cell death. Simultaneous measurements of the externaland intracellular pH revealed the promotion of external acidificationand internal alkalization during salt stress. Possible mechanismsof Na+/H+ antiport at the tonoplast and the role of proton-pumpin the plasma membrane are discussed.
3Present address: Shijonawate Gakuen Women's Junior College,Daito, Osaka, 574 Japan. 相似文献
92.
Tetsuro Mimura Mari Mimura Setsuko Washitani-Nemoto Katsuhiro Sakano Teruo Shimmen Somkid Siripatanadilok 《Journal of plant research》1997,110(1):25-29
Experimental conditions for efficient callus initiation from mangrove plants were investigated. As a source explant, leaf
ofBruguiera sexangula was used. Mangrove plant is one of the most famous woody plants which can grow at the salty area. The initiated callus can
be a suitable material for the investigation of salt tolerant mechanisms of mangrove plants.
Leaf pieces cultured in an Amino Acid medium supplemented with 2 μM 2,4-dichlorophenoxyacetic acid and 2 μMN-(2-chloro-4-pyridyl)-N′-phenylurea at 30 C developed calluses. Microscopic observation suggested that the callus was initiated from the tissue in
the vascular bundles in the leaf.
We also examined the effect of NaCl on callus initiation and short-term culture of the calluses on the leaves. Callus initiation
rate decreased with increasing NaCl concentration higher than 100 mM in the culture media. The medium containing 100 mM NaCl
produced the largest callus on the leaf, compared with higher or lower concentrations of NaCl. 相似文献
93.
94.
95.
Bhavin Shah Daniela Lutter Magdalena L. Bochenek Katsuhiro Kato Yaroslav Tsytsyura Natalia Glyvuk Akira Sakakibara Jürgen Klingauf Ralf H. Adams Andreas W. Püschel 《PloS one》2016,11(4)
The establishment of a polarized morphology is essential for the development and function of neurons. During the development of the mammalian neocortex, neurons arise in the ventricular zone (VZ) from radial glia cells (RGCs) and leave the VZ to generate the cortical plate (CP). During their migration, newborn neurons first assume a multipolar morphology in the subventricular zone (SVZ) and lower intermediate zone (IZ). Subsequently, they undergo a multi-to-bipolar (MTB) transition to become bipolar in the upper IZ by developing a leading process and a trailing axon. The small GTPases Rap1A and Rap1B act as master regulators of neural cell polarity in the developing mouse neocortex. They are required for maintaining the polarity of RGCs and directing the MTB transition of multipolar neurons. Here we show that the Rap1 guanine nucleotide exchange factor (GEF) C3G (encoded by the Rapgef1 gene) is a crucial regulator of the MTB transition in vivo by conditionally inactivating the Rapgef1 gene in the developing mouse cortex at different time points during neuronal development. Inactivation of C3G results in defects in neuronal migration, axon formation and cortical lamination. Live cell imaging shows that C3G is required in cortical neurons for both the specification of an axon and the initiation of radial migration by forming a leading process. 相似文献
96.
Fourteen species of Characeae were analyzed for their free amino acids. This study, in combination with previous results (Sakanoet al., 1984) showed that all the species that belong to the generaChara (6 species),Lamprothamnium (1 species),Nitellopsis (1 species),Lychnothammus (1 species) and 5Nitella species of the members of the subsectionAnarthrodactylae contained a large amount of isoasparagine. In contrast, no isoasparagine was found in the species belonging toTolypella (3 species) and otherNitella (7 species). Presence of isoasparagine in some species of Characeae (N. flexillis andNitellopsis obtusa) was found to be independent of their localities (Japan, Canada and England). Species lacking isoasparagine (N. oligogyra and N. axilliformis) did not produce isoasparagine even under the condition that induced a great increase of this amino acid in the species that
contained it (C. corallina andN. flexilis). These results indicate that isoasparagine is a distinct taxonomic marker and suggest that theNitella species of the subsectionAnarthrodactylae are the most primitive group inNitelleae in that they share synthesis and accumulation of isoasparagine withChareae and, hence, support the view (Kasaki, 1964) that the subsection may be treated as an independent genus. 相似文献
97.
Sadayuki F. Takagi Gordon A. Wyse Harunobu Kitamura Katsuhiro Ito 《The Journal of general physiology》1968,51(4):552-578
In order to clarify whether or not the electronegative olfactory mucosal potentials (EOG) are generator potentials, the effects of changed ionic enviroment were studied. The EOG decreased in amplitude and in some cases nearly or completely disappeared, when Na+ in the bathing Ringer solution was replaced by sucrose, Li+, choline+, tetraethylammonium+ (TEA), or hydrazine. In the K+-free Ringer solution, the negative EOG's initially increased and then decreased in amplitude. In Ringer's solution with increased K+, the negative EOG's increased in amplitude. When K+ was increased in exchange for Na+ in Ringer's solution, the negative EOG's decreased, disappeared, and then reversed their polarity (Fig. 6). Next, when the K+ was replaced by equimolar sucrose, Li+, choline+, TEA+, hydrazine, or Na+, the reversed potentials recovered completely only in Na+-Ringer's solution, but never in the other solutions. Thus, the essential role of Na+ and K+ in the negative EOG's was demonstrated. Ba++ was found to depress selectively the electropositive EOG, but it hardly decreased and never increased the negative EOG. Hence, it is concluded that Ba++ interferes only with Cl- influx, and that the negative EOG's are elicited by an increase in permeability of the olfactory receptive membrane to Na+ and K+, but not to Cl-. From the ionic mechanism it is inferred that the negative EOG's are in most cases composites of generator and positive potentials. 相似文献
98.
Sequence Analysis of Cloned cDNA and Proteolytic Fragments for Nitrate Reductase from Spinacia oleracea L. 总被引:1,自引:0,他引:1
Shiraishi Naomasa; Kubo Yoshihiro; Takeba Go; Kiyota Seiichiro; Sakano Katsuhiro; Nakagawa Hiroki 《Plant & cell physiology》1991,32(7):1031-1038
Proteolytic fragments were obtained by limited proteolysis of120 kDa nitrate reductase from Spinacia oleracea L. using trypsinand Staphylococcus aureus V8 protease. Determination of NH2-terminalsequences in 9 to 14 Edman degradation steps allowed the exactlocalization of the fragments within the amino-acid sequenceof spinach nitrate reductase was deduced from the nucleotidesequence of cDNA clone pSPNR117 which was initially identifiedby hybridization to squash nitrate reductase cDNA clone [Crawford,1N. M., Campbell, W. H. and Davis, R. W. (1986) Proc. Natl. Acad.Sci. USA 83: 8073] and anti spinach nitrate reductase polyclonalantibodies. This clone has a 2324 base insert, and the aminoacid sequence deduced from its open reading frame, which contains640 residues. The predicted sizes 42.5 and 30 kDa were in reasonableagreement with previous determination of the apparent molecularsizes of the FAD-cyt-chrome b557-binding, and FAD-binding fragments,respectively. Arginine residue was the cleavage site for trypsin and glutamicacid was for S. aureus V8 protease. The amino acid residueswithin the linker regions which connect the functional domains,could be cleaved with trypsin or S. aureus V8 protease may bewell conserved in the amino acid sequences deduced from thenitrate reductase cDNA sequences. A sequence identity of 61.2-80.1 % was found in the amino acidsequences deduced from the cDNA sequences as obtained by spinachand other higher plant nitrate reductases. However, the aminoacid sequences surrounding the proteolytic cleavage sites ofnitrate reductase had poor homology. (Received March 30, 1991; Accepted July 24, 1991) 相似文献
99.
Summary We have established a unique betalain pigmentation system in callus cultures that originated from seedlings of Portulaca sp. Jewel. Within three different Jewel lines examined, one line (JR) was clearly superior with regard to callus growth rate and pigment formation. Furthermore, after ten cycles of selection of deeply colored callus patches, the selected clones contained on an average four times the amount of betalain as compared to the non-selected mother line. The colorization was induced by light, but disappeared in the dark. Pigment synthesis was detectable within 30 h after irradiation and showed positive correlation with irradiation periods.Abbreviations 2,4-D
2,4-dichlorophenoxy-acetic acid
- HPLC
high performance liquid chromatography 相似文献
100.
Katsuhiro Sakano Teruo Shimmen Shin-Ichi Hatanaka Masashi Tazawa 《Journal of plant research》1984,97(1):81-85
Thirteen species of Characeae were analyzed for their free amino acid contents. Large amounts of isoasparagine, accounting
for 10 to 50% of the total free amino acids, were found in extracts fromChara (5 species including one unidentified),Nitellopsis (1 species), andLamprothamnium (1 species). In contrast, no isoasparagine was detected inNitella (5 species) andTolypella (1 species), except forN. flexilis in which as much as 40% of the free amino acids was isoasparagine. Other major amino acids found in the tested materials
were Ala, Asp, Glu and Gln. 相似文献