全文获取类型
收费全文 | 212篇 |
免费 | 12篇 |
国内免费 | 11篇 |
专业分类
林业 | 20篇 |
农学 | 16篇 |
基础科学 | 5篇 |
71篇 | |
综合类 | 71篇 |
农作物 | 22篇 |
水产渔业 | 7篇 |
畜牧兽医 | 6篇 |
园艺 | 4篇 |
植物保护 | 13篇 |
出版年
2024年 | 3篇 |
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 18篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 21篇 |
2013年 | 26篇 |
2012年 | 13篇 |
2011年 | 15篇 |
2010年 | 4篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有235条查询结果,搜索用时 697 毫秒
1.
The plants of field bean var. Nadwiślaνski were detopped after about 1 month since the beginning of flowering and after that all flower buds were removed from some plants. The effect of a change in the trophic balance on the setting and subsequent growth of root nodules was studied.
The removal of pods had the greater effect on the increase in the weight of the remaining organs than the detopping of plants. Detopping retarded the ageing of the plants and delayed the phase of the greatest reduction of the number of pods. The detopping of plants revealed their considerable compensative possibilities in terms of production of the pod weight and the potential of leaves for biomass production. The data obtained indicate that plant detopping may disturb the root–bacteria exchange of signals, necessary to initiate the nodule development, while the further growth of nodules depends, above all, on the amount of available photosynthates.
A very high correlation between the dry weight of the whole plant to the dry weight of leaves ratio and the weight of nodules was observed. It proves the importance of the trophic balance of the plant for the root nodule weight production. 相似文献
The removal of pods had the greater effect on the increase in the weight of the remaining organs than the detopping of plants. Detopping retarded the ageing of the plants and delayed the phase of the greatest reduction of the number of pods. The detopping of plants revealed their considerable compensative possibilities in terms of production of the pod weight and the potential of leaves for biomass production. The data obtained indicate that plant detopping may disturb the root–bacteria exchange of signals, necessary to initiate the nodule development, while the further growth of nodules depends, above all, on the amount of available photosynthates.
A very high correlation between the dry weight of the whole plant to the dry weight of leaves ratio and the weight of nodules was observed. It proves the importance of the trophic balance of the plant for the root nodule weight production. 相似文献
2.
青蛙放养个体大小对稻蛙共育效益的影响 总被引:1,自引:0,他引:1
稻蛙共育是一种新的生态稻作模式,高产高效,但在青蛙繁育过程中,由于个体差异,造成稻田可套养时单体质量低于100 g的青蛙数量较多。针对这一情况,笔者对稻田放养单体质量低于100 g青蛙对治虫、养殖效益的影响开展了对比试验。结果表明,稻蛙共育中采用单体质量75g的青蛙放养是可行的,能基本达到100 g单体质量青蛙的放养效果。 相似文献
3.
To determine whether senescing leaves provoke an active nitrogen (N) remobilization that results in the reduction of nitrogenase activity, 60% of Medicago truncatula lower leaves were either darkened or individually excised for two weeks. Although a considerable amount of N was remobilized, N2 fixation activity was found to be increased to maintain the N source/sink balance, indicating an absence of the negative N‐feedback regulation of nitrogenase activity in the senescing M. truncatula. 相似文献
4.
产业融合共生是新时期红色旅游的必然选择,红色旅游企业共生系统可分为区域内共生子系统和区域外共生子系统,表现为核心共生、主要共生和跨界共生三种形态,核心共生形态是红色旅游企业共生区别其他企业共生的根本所在。红色旅游企业共生由合作和共识耦合而成,但核心共生形态的形成机理更多地表现为天然性,要求红色旅游企业主动寻求合作,争取与其他共生单元达成共识,促进红色旅游企业共生关系的良性发展。 相似文献
5.
F. P. Baijukya E. Semu 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):175-183
A glasshouse study was undertaken to investigate the effects of the copper fungicide Kocide 101 and its residues in soil on the growth, nodulation and nitrogen fixation of beans (Phaseolus vulgaris L.). The soil used was a sandy clay loam classified as Typic Rhodustalf. The bean variety SUA 90 was used as test crop. The bean rhizobia strains CIAT 899, PV, and a local isolate were used. Kocide 101 applied at the recommended rate (equivalent to 1.7 mg kg‐1 soil) had no significant negative effects on the growth, nodulation or nitrogen fixation of bean plants. Higher levels of Kocide 101 significantly (P < 0.05) reduced plant growth, nodulation and nitrogen fixation. The bean plants inoculated with the “local isolate”; rhizobia had the highest dry matter weights, nodule numbers and nodule dry weights, and also had more N fixation. They were followed by those inoculated with the PV, strain and, lastly, those inoculated with CIAT 899. The growth and nodulation of bean plants were still curtailed by the Kocide 101 residues four months after the fungicide was first applied to the soil. Therefore, occurrence of high levels of Kocide 101 in soils can have long‐term effects on the performance of the bean‐rhizobia symbiosis. 相似文献
6.
沃尔巴克氏体(Wolbachia,Wb)是在丝虫体内发现的一类共生菌,它诱导的免疫病理引起的炎症反应是丝虫感染后致病的主要原因之一。论文论述了丝虫沃尔巴克氏体的分类、结构与分布、生殖及传播方式、基因组和沃尔巴克氏体与丝虫之间的相互作用关系,重点阐述了沃尔巴克氏体与丝虫致病性和清除沃尔巴克氏体药物在人和动物丝虫病治疗中的作用,为人和动物丝虫病的防治研究提供参考。 相似文献
7.
Reef-building corals are in symbiosis with the dinoflagellates Symbiodinium spp. In our previous study, the expression of two mRNAs (AtSym-01 and 02) was up-regulated by the presence of Symbiodinium cells (strain PL-TS-1) in juveniles of the reef-building coral Acropora tenuis. In this study, the AtSym-01 mRNA was found to encode a cnidarian ortholog of the vertebrate SLC26A11 sulfate transporter. The AtSym-01 and human SLC26A11
proteins exhibited 46% identity over 542 amino acids. Real-time polymerase chain reaction analysis showed that the expression
level of the AtSym-01 mRNA was also increased by the presence of Symbiodinium strain CCMP2467 cells. Immunohistochemical analysis was performed using polyclonal antibodies against the AtSym-01 protein,
in order to study the distribution of the protein in A. tenuis tissues. Cell-specific immunoreaction was observed in diverse tissues in juvenile and adult specimens. Notable immunoreaction
was observed in mucocytes (mucus cells) in the outer epithelium of juveniles, and gastrodermal cells located between the coelenteron
and skeleton of the adult colony. These observations suggest the possibility that the AtSym-01 protein is involved in uptake
of sulfate ion for synthesis of sulfated macromolecules that are contained in the mucus and organic matrix of the calcified
skeleton. 相似文献
8.
9.
生菜叶中磷含量的光谱定量分析 总被引:1,自引:0,他引:1
为快速、准确检测生菜叶内的磷含量,提出了应用光谱技术结合化学计量法无损检测生菜叶内磷含量的方法。通过获取不同施磷量下生菜叶片于波长350~2500nm处的反射光谱,对光谱数据进行5点平滑和一阶导数变换后,利用联合区间偏最小二乘算法(siPLS)提取了与生菜叶磷元素相关的4个特征波段,即950~1070nm, 1430~1549nm,1906~2025nm和2144~2263nm。进一步利用连续投影算法(SPA)对全光谱波段和4个特征波段进行特征波长提取,分别筛选出变量63个和25个。分别对4个特征波段、63个和25个特征波长进行主成分降〖JP2〗维,当主成分数分别为7、5和4时,隐含层神经元数分别为7、5和3时,建立了siPLS+BPANN,SPA+BPANN,siPLS+〖JP〗SPA+BPANN生菜叶磷含量检测模型。研究结果表明:siPLS+SPA+BPANN模型的预测结果优于其他模型,验证集相关系数为0.911,验证均方根误差为479mg/kg。 相似文献
10.
André Horta Susete Pinteus Celso Alves Nádia Fino Joana Silva Sara Fernandez Américo Rodrigues Rui Pedrosa 《Marine drugs》2014,12(3):1676-1689
Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds. 相似文献