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41.
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43.
Mitsuteru Suzuki Pramod Tandon Masaya Ishikawa Takayuki Toyomasu 《Plant biotechnology reports》2008,2(2):123-131
Vitrification methods are convenient for cryopreserving plant specimens, as the specimens are plunged directly into liquid
nitrogen (LN) from ambient temperatures. However, tissues and species with poor survival are still not uncommon. The development
of vitrification solutions with high survival that cover a range of materials is important. We attempted to develop new vitrification
solutions using bromegrass cells and found that VSL, comprising 20% (w/v) glycerol, 30% (w/v) ethylene glycol, 5% (w/v) sucrose,
10% (w/v) DMSO and 10 mM CaCl2, gave the highest survival following cryopreservation, as determined by fluorescein diacetate staining. However, the cryopreserved
cells showed little regrowth, for unknown reasons. To check its applicability, VSL was used to cryopreserve gentian axillary
buds and the performance was compared with those of conventional vitrification solutions. Excised gentian stem segments with
axillary buds (shoot apices) were two-step precultured with sucrose to induce osmotic tolerance prior to cryopreservation.
Gentian axillary buds cryopreserved using VSL following the appropriate preculturing approach exhibited 78% survival (determined
by the regrowth capacity), which was comparable to PVS2 and PVS1 and far better than PVS3. VSL had a wider optimal incubation
time (20–45 min) than PVS2 and was more suitable for cryopreserving gentian buds. The optimal duration of the first step of
the preculture was 7–11 days, and preculturing with sucrose and glucose gave a much higher survival than fructose and maltose.
VSL was able to vitrify during cooling to LN temperatures, as glass transition and devitrification points were detected in
the warming profiles from differential scanning calorimetry. VSL and its derivative, VSL+, seem to have the potential to be
good alternatives to PVS2 for the cryopreservation of some materials, as exemplified by gentian buds.
Mitsuteru Suzuki, Pramod Tandon and Masaya Ishikawa contributed equally to the work. 相似文献
44.
Toyomasu T Kagahara T Okada K Koga J Hasegawa M Mitsuhashi W Sassa T Yamane H 《Bioscience, biotechnology, and biochemistry》2008,72(2):562-567
Rice (Oryza sativa L.) produces a variety of diterpene phytoalexins, such as momilactones, phytocassanes, and oryzalexins. Momilactone B was previously identified as an allelopathic substance exuded from the roots of rice. We identified in this present study momilactone A and phytocassanes A-E in extracts of, and exudates from, the roots of rice seedlings. The concentration of each compound was of the same order of magnitude as that of momilactone B. Expression analyses of the diterpene cyclase genes responsible for the biosynthesis of momilactones and phytocassanes suggest that these phytoalexins found in roots are primarily biosynthesized in those roots. None of phytocassanes B-E exhibited allelopathic activity against dicot seedling growth, whereas momilactone A showed much weaker allelopathic activity than momilactone B. The exudation of diterpene phytoalexins from the roots might be part of a system for defense against root-infecting pathogens. 相似文献
45.
H Toshima H Oikawa T Toyomasu T Sassa 《Bioscience, biotechnology, and biochemistry》2001,65(5):1244-1247
The drimane sesquiterpenes, (+)-albicanol (2) and (+)-albicanyl acetate (3), were synthesized from an optically active bicyclic diol [(+)-1] that had been obtained via the recently developed optical resolution of a general synthetic intermediate for drimane sesquiterpenes. The crucial step in the previous syntheses was markedly improved by the modified Wittig methylenation of a silyloxy ketone (7). The high overall yield (77% in 4 or 5 steps from (+)-1) by this total synthesis makes it possible to synthesize the other biologically active drimane sesquiterpenes. 相似文献
46.
Immunoglobulin class switch involves a unique recombination event that takes place at the region 5′ to each heavy chain constant region gene during B lymphocyte differentiation. Such regions that are responsible for the class-switch recombination are defined as S regions (Kataoka et al., Proc. Natl. Acad. Sci. USA 77, 919, 1980). We have cloned a rearranged γ2b gene from a mouse myeloma (MPC11) and compared its structure with the germ line counterparts. The rearranged γ2b gene contained the 5′ flanking region of the γ3 gene (Sγ3 region) which are linked to the 5′ flanking region of the γ2b gene (Sγ2b region). We have determined nucleotide sequences surrounding the recombination site of the rearranged and germ line γ2b genes, which include the Sγ2b and Sγ3 regions. Both γ2b and Sγ3 regions comprise tandem repetition of conserved units of 49 bp. Similar 49 bp repeating units are also found in the previously determined sequence of the Sγ1 region in which class-switch recombination took place in MC101 myeloma. The nucleotide sequences of the Sγ1, Sγ2b and Sγ3 repeating units share significant homology with each other. The Sμ region, partial nucleotide sequence of which was previously determined, contains abundant short sequences such as AGCT, TGGG and AGCTGGGG which are shared in common by repeating sequences in Sγ regions. These results suggest that the recombination responsible for class switch from μ to γ or from a γ to another γ, may be facilitated directly or indirectly by homology of repeating sequences in S regions. 相似文献
47.
48.
Zen-ichiro Hamauzu Tetsuo Toyomasu Daizo Yonezawa 《Bioscience, biotechnology, and biochemistry》2013,77(12):2445-2450
Gliadin was fractionated into three fractions; ω-gliadin, Fraction III (γ-gliadin) and Fraction IV (α- and β-gliadin). The determination of the molecular weights (MW) of the three fractions was performed by both SDS-polyacrylamide gel electrophoresis (SDS–PAGE) and sedimentation equilibrium. In SDS–PAGE, ω-gliadin gave three bands (MW 50,000, 54,000 and 64,000), Fraction III two bands (MW 38,000 and 46,000) and Fraction IV two bands (MW 33,000 and 38,000), The sedimentation analysis showed that each fraction was fairly homogeneous relative to molecular weight. The molecular weights obtained by sedimentation were 28,000 for Fraction III and 27,000 for both Fraction IV and ω-gliadin. The disagreement in molecular weight between sedimentation and gel electrophoresis was discussed. 相似文献
49.
PRL family constitutes a unique class of phosphatases associated with metastasis. The phosphatase activity of PRL has been reported to be important for promoting metastasis, and it is inactivated by reversible oxidation of its catalytic cysteine. Here, we show that TRP32 specifically reduces PRL. Reduction of oxidized PRL in cells is inhibited by 2,4-dinitro-1-chlorobenzene, an inhibitor of TRX reductase. In vitro assays for the reduction of PRL show that only TRP32 can potently reduce oxidized PRL, whereas other TRX-related proteins linked to TRX reductase show little or no reducing activity. Indeed, TRP32 knockdown significantly prolongs the H2O2-induced oxidation of PRL. Binding analyses reveal that the unique C-terminal domain of TRP32 is required and sufficient for its direct interaction with PRL. These results suggest that TRP32 maintains the reduced state of PRL and thus regulates the biological function of PRL. 相似文献
50.
Retardation of bone development was observed in the Koshima troop of free ranging Japanese macaques. In the control group,
epiphyseal unions of appendicular long bones generally started to close at about 4 yrs of age and were completed at about
8 or 9 yrs of age. Limb bone unions of the Koshima troop, however, started to close at about 9 yrs of age and completely closed
at about 15 yrs of age. In the epiphyseal unions of trunk and girdle bones, the Koshima troop again showed a retardation of
closure compared with the control group. Until long bones reached their full length, that is, until about 15 yrs of age, their
size was small in the Koshima troop compared with the control group, though the sample size of the Koshima troop was small.
After 15 yrs of age, however, many osteometrical measurements of the Koshima troop were nearly the same as controls. A prolonged
growing duration compensated for the slow growth and allowed them to become as large as controls. This prolongation may be
an adaptation in response to small size during the developmental period.
In some parts of the body, however, Koshima macaques failed to reach the adult size of controls. Males were less likely than
females to reach full size. Causes of the retardation and small size in the Koshima troop are discussed, but they remain open
to further studies. 相似文献