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排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
The circadian rhythms in activity, core temperature (Tc), O2 consumption, CO2 production, and respiratory quotient (RQ) were monitored in four captive Chinese pangolins (Manis pentadactyla). The pangolins were strictly nocturnal, never emerging from their nest before 1600 h, and their intermittent activity continued no later than 0230. As is usual in nocturnal mammals, the highest values observed in Tc, O2 consumption, and CO2 production occurred during the night; the lowest values occurred during the day. The magnitude of the variation in Tc, O2 consumption, CO2 production, and RQ averaged 1.2°C, 1.3 ml O2 kg?1 min?1, 1.2 ml CO2 kg?1 min?1, and 0.24, respectively. The circadian pattern in RQ was independent of activity, Tc, and the metabolic parameters and was of a different character than the patterns exhibited in the other variables. RQ remained constant at either a high or low level for long periods (8–10 h) and then increased or decreased relatively rapidly (1–2h) to the other level as in a square wave, whereas the rhythms in the other variables are similar to sine waves. The sharp increase in RQ was followed by a slow decline in Tc, and the sharp decline in RQ was followed by a slow increase in Tc.  相似文献   
2.
鸦胆子抗肿瘤活性成分的化学研究   总被引:6,自引:0,他引:6  
从苦木科植物鸦胆子[Brucea javanica(L.)Merr]干躁果实的硅胶干柱柱层析所得的活性部位中经层析分离得到7个四环三萜苦木内酯成份(A,B,C,D,E,F,G),经UV,IR,~1H-NMR,~(13)C-NMR等方法鉴定分别为鸦胆苦醇(Brusatol A),双氢鸦胆苦醇(Dihydrobrusatol,B),鸦胆因B(Bruceine B,C),鸦胆因D(Bruceine D,D),鸦胆因H(Bruceine H,E),鸦胆子甙A(Bruceoside A,F)和双氢鸦胆子甙A(Yadanzioside A,G)。据报道,鸦胆苦醇和鸦胆子甙A具有较强的抗肿瘤活性。  相似文献   
3.
The effect of four opportunistic fungi viz., Paecilomyces lilacinus, Cladosporium oxysporum, Gliocladium virens and Talaromyces flavus on the life cycle of the root-knot nematode, Meloidogyne javanica, on brinjal was evaluated under glasshouse conditions. The results revealed that these fungi affected the penetration and development of M. javanica. The life cycle of M. javanica was delayed by 10, 7, 4 and 2 days in the presence of P. lilacinus, C. oxysporum, G. virens and T. flavus respectively. Fecundity, number of eggs per eggmass and number of larvae was also reduced in the presence of these opportunistic fungi. However, the number of males increased in the presence of opportunistic fungi.  相似文献   
4.
Four new biphenyl derivatives ( 1 – 4 ), along with six known biphenyl derivatives ( 5 – 10 ) were isolated and elucidated by their detailed analyses of spectroscopic data and references from the aerial parts of Oenanthe javanica for the first time. Compounds ( 1 – 10 ) were assayed for their activities about the inhibition of COX‐2 enzyme in vitro for the first time. Compounds 1 , 2 , 4 , and 6 showed inhibitory activities against COX‐2 with IC50 values ranging from 22.18±0.29 to 108.54±0.42 μm .  相似文献   
5.
Flowering activity and sex expression of Bischofia javanica Blume were investigated for 3 years. B. javanica is an invasive dioecious tree of subtropical forests on the Bonin Islands in the western Pacific of Japan. The sex ratio showed a significant male bias (1.25-2.33). Smaller trees were significantly male biased, whereas larger trees showed no significant difference in sex expression, suggesting that males tend to be more precocious in sexual reproduction. We found evidence for sex changes in B. javanica; these have not been reported previously. Most of the 1,653 census trees remained non-flowering (58.1 %); 3.7 % of them showed sex changes, and the percentage of trees repeatedly flowering as males and females was 10.5 and 3.4 %, respectively. Sex changes were observed in both directions but a larger percentage of male trees became female. Flowering frequency and sex expression were significantly related to tree size (i.e. diameter at breast height). Over the 3 years, trees that were consistent females were the largest; inconsistent trees (switching sex between years) were intermediate in size, whereas consistent males were the smallest. There were no significant differences in relative growth rate (RGR) among trees of different sex or flowering frequencies. These results suggest that the maintenance of female reproduction is not related to changes in RGR of diameter but to flowering frequency or the reversal to the male form, dependent upon the internal resource status of individual trees.  相似文献   
6.
Aims: To determine the potential of the plant‐parasitic nematode Meloidogyne javanica to serve as a temporary reservoir for Escherichia coli. Methods and Results: The adhesion to and persistence of E. coli on the surface of M. javanica were evaluated at different times and temperatures. A pure culture of green fluorescent protein (GFP) tagged E. coli was mixed with ca. 1000 J2 M. javanica for 2 h at 25°C. The nematodes were then washed and the rate of the adhesion of the bacteria to the nematodes was determined by counting the viable nematode‐associated E. coli, and by fluorescence microscopy. A dose‐dependent adhesion rate was observed only at a bacterium to nematode ratio of 104–106 : 1. The adhesion of E. coli to the nematodes was also tested over a 24 h‐period at 4°C, 25°C and 37°C. At 4°C and 37°C, maximal adhesion was observed at 5 h; whereas at 25°C, maximal adherence was observed at 8 h. Survival experiments showed that the bacteria could be detected on the nematodes for up to 2 weeks when incubated at 4°C and 25°C, but not at 37°C. Conclusions: Under laboratory conditions, at 4°C and 25°C, M. javanica could serve as a temporary vector for E. coli for up to 2 weeks. Significance and Impact of the Study: These findings support the hypothesis that, in the presence of high concentrations of E. coli, M. javanica might serve as a potential vehicle for the transmission of food‐borne pathogens.  相似文献   
7.
New pregnane glycosides from Brucea javanica and their antifeedant activity   总被引:1,自引:0,他引:1  
Three new pregnane glycosides, 3-O-β-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl-(20R)-pregn-5-ene-3β,20-diol (1), 3-O-α-L-arabinopyranosyl-(20R)-pregn-5-ene-3β,20-diol-20-O-β-D-glucopyranoside (2), 3-O-α-L-arabinopyranosyl-(20R)-pregn-5-ene-3β,20-diol-20-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (3) were isolated along with four known compounds, 4-7, from the leaves and stems of Brucea javanica. Their structures were determined by detailed analyses of 1D- and 2D-NMR spectroscopic data. All of the compounds isolated from Brucea javanica were tested for the antifeedant activities against the larva of Pieris rapae. Compounds 1, 3, and 5 showed significant antifeedant activities after 72 h incubation.  相似文献   
8.
目的研究中国穿山甲消化道5-羟色胺(5-HT)免疫活性细胞的分布和形态。方法应用链霉菌抗生物素蛋白一过氧化物酶免疫组织化学方法(S-P法)。结果中国穿山甲消化道5-HT细胞在胃幽门部密度最高,食道、胃贲门部和胃体中未见分布。肠道5-HT细胞密度从十二指肠、空肠到回肠依次减少,至大肠又显著升高(P〈0.01)。5-HT细胞形态多样,主要有圆形、椭圆形和锥形,肠上皮中锥形5-HT细胞通过顶部较长的胞突通向肠腔,基部较宽的胞体与固有层相接触。结论中国穿山甲消化道5-HT细胞的分布和形态同其它动物有相似之处,也有其自身特点。中国穿山甲消化道中5-HT细胞的分布与其食性是相适应的。  相似文献   
9.
The effects of arbuscular mycorrhizae (AM) on the development and nutrition of the peach almond hybrid GF-677 rootstock in a replant soil heavily infested with Meloidogyne javanica were evaluated in field microplot conditions for two growing seasons. There was a significant beneficial effect of mycorrhizal inoculation on plant growth and nutrition in previously pasteurized replant soil. In natural replant soil, early inoculation with a mixed AM inoculum of Glomus intraradices, Glomus mosseae and Glomus etunicatum did not affect growth parameters. Whilst inoculation with these AM fungi led to suppression of root-knot nematode reproduction, natural mycorrhizal colonization of the replant soil with native AM fungi did not. Accepted: 6 December 2000  相似文献   
10.
马来穿山甲(Manis javanica)为极度濒危物种,已报导该物种的怀孕期长度差异较大,需要更多的直接观察案例来确定其怀孕期长短。广西林业科学研究院穿山甲人工救护与繁育基地通过室内圈养方式驯养穿山甲,记录了14例马来穿山甲产仔情况:其中圈养前野外受孕、场内产仔9例;野外受孕、圈养死亡的母体1例;不确定受孕情况母兽产仔1例;圈养条件下交配怀孕并产仔3例,其中2例是母兽进场后第2次产仔。根据初步观察结果,估计马来穿山甲孕期为5~6个月。  相似文献   
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