首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   510篇
  免费   85篇
  国内免费   171篇
  2023年   7篇
  2022年   8篇
  2021年   11篇
  2020年   41篇
  2019年   29篇
  2018年   4篇
  2017年   16篇
  2016年   26篇
  2015年   55篇
  2014年   23篇
  2013年   50篇
  2012年   38篇
  2011年   39篇
  2010年   31篇
  2009年   46篇
  2008年   41篇
  2007年   30篇
  2006年   29篇
  2005年   30篇
  2004年   28篇
  2003年   28篇
  2002年   24篇
  2001年   12篇
  2000年   18篇
  1999年   14篇
  1998年   23篇
  1997年   12篇
  1996年   7篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   1篇
  1988年   3篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1982年   6篇
  1981年   1篇
  1978年   2篇
  1977年   1篇
排序方式: 共有766条查询结果,搜索用时 15 毫秒
1.
采用对峙培养法、凹玻片法、LB琼脂培养基萌发法测定短小芽孢杆菌AR03对烟草赤星病菌和白粉病菌的抑制作用.结果表明: AR03菌液对2种病菌的菌丝生长和分生孢子萌发均有明显的拮抗作用;对赤星病菌的抑制作用表现为:经AR03菌液原液(3×108cfu·mL-1)处理的菌丝隔间变短、肿胀且集结成团,内含物聚集,菌丝顶端生长膨大畸形;经该菌液处理的赤星病菌分生孢子不萌发或萌发产生畸形芽管,分生孢子变形、肿大,纵横分隔部分的组织膨胀呈泡状.AR03菌液原液、30倍液和200倍液对白粉病菌分生孢子萌发的平板抑制率分别为100%、91.4%和 69.3%,菌液对分生孢子萌发的破坏作用表现为分生孢子不萌发,细胞肿胀变形、细胞原生质解体或收缩,孢子内、外壁分离,由于原生质外泄,一些分生孢子内部呈中空状.温室防治试验结果表明: 不同浓度AR03菌悬液处理对烟草白粉病的防治效果存在显著差异,第二次药后7和15 d,AR03菌液原液的防治效果分别达到83.8%和90.3%,与对照药剂差异不显著;而100倍稀释液的防效分别为70.0%和73.3%,与对照药剂差异显著.AR03菌株防治白粉病的持效期为30 d以上.  相似文献   
2.
The viability of conidia from two species of deuteromycetes fungi pathogenic to insects was determined using two fluorochrome stains, fluorescein diacetate (FDA) and propidium iodide (PI). These stains were used either alone or in combination, and results were compared with standard conidial germination tests. FDA fluoresces bright green in viable conidia and PI fluoresces red in non-viable conidia, when viewed using specific fluorescence microscopic techniques. Conidia from two isolates of Paecilomyces fumosoroseus (Wize) Brown and Smith and two isolates of Beauveria bassiana (Balsamo) Vuillemin were evaluated. Conidia were suspended in deionized water and half of each suspension was treated with microwave radiation to kill all the conidia. Conidia were tested for viability in non-microwaved suspensions in a mixture (ca. 1:1) of viable and non-viable conidial suspensions, and in the microwaved suspensions that contained all non-viable conidia. No significant differences were observed for the four isolates tested between germination tests on water and agar and viability tests conducted with FDA alone or FDA in combination with PI. One isolate of B. bassiana that had been damaged in storage was also tested. Differences were observed between the actual germination and the percentage of viability determined using FDA or FDA plus PI. Damaged conidia maintained a measure of viability and fluoresced green, but did not fully germinate.  相似文献   
3.
The effect of simulated rain at two intensities (26.7 or 112.7 mm h-1) and durations (30 or 60 min) on the persistence of Beauveria bassiana conidia applied in water on leaves of alfalfa leaves of alfalfa (Medicago sativa) or wheat (Triticum aestivum) was investigated. Initial populations of conidia on the leaves of both crops were similar, and ranged from 1.7 105 to 3.5 105 colony-forming units cm-2. The simulated rain reduced the concentration of conidia on leaves by 28-61%. Although there was a slight effect due to rain intensity for alfalfa, there was no influence of either rain duration or crop type on the retention of B. bassiana conidia.  相似文献   
4.
We evaluated biopesticides based on entomopathogenic fungi, azadirachtin and horticultural oils for the management of the chilli thrips, Scirtothrips dorsalis Hood, an economically significant invasive pest in the United States. Insecticides were applied four times at 7‐ to 10‐day intervals against established S. dorsalis infestations on shrub roses KnockOut®, Rosa x ‘Radrazz’ under simulated nursery conditions. When applied as stand‐alone treatments, Beauveria bassiana GHA (BotaniGard® ES), Metarhizium brunneum F52 (Met‐52 EC), a horticultural oil (SuffOil‐X®) and azadirachtin (Molt‐X®) at label rates provided significant control, reducing populations of S. dorsalis by 48–71% compared with control over 4–6 weeks. Similar results were observed when the biopesticides were applied in rotation with each other. A conventional standard, spinosad (Conserve® SC), was consistently the most effective treatment in these studies, reducing thrips populations by >95% overall. In another study, more effective control (87%–92%) was achieved in biopesticide rotation programmes that included spinosad, when compared with those that did not. Results also showed that these biopesticides can be tank‐mixed. However, there was no evidence that B. bassiana or M. brunneum combined with azadirachtin resulted in additive or synergistic control, as neither tank‐mix treatment improved control compared with azadirachtin alone. These findings highlight the potential use of biopesticides in rotation programmes with conventional insecticides to manage S. dorsalis on roses. Biopesticides evaluated in this study can be incorporated into an IPM programme for roses.  相似文献   
5.
6.
Iwona Wojda 《Insect Science》2017,24(3):342-357
Investigation of insect immune mechanisms provides important information concerning innate immunity, which in many aspects is conserved in animals. This is one of the reasons why insects serve as model organisms to study virulence mechanisms of human pathogens. From the evolutionary point of view, we also learn a lot about host–pathogen interaction and adaptation of organisms to conditions of life. Additionally, insect‐derived antibacterial and antifungal peptides and proteins are considered for their potential to be applied as alternatives to antibiotics. While Drosophila melanogaster is used to study the genetic aspect of insect immunity, Galleria mellonella serves as a good model for biochemical research. Given the size of the insect, it is possible to obtain easily hemolymph and other tissues as a source of many immune‐relevant polypeptides. This review article summarizes our knowledge concerning G. mellonella immunity. The best‐characterized immune‐related proteins and peptides are recalled and their short characteristic is given. Some other proteins identified at the mRNA level are also mentioned. The infectious routes used by Galleria natural pathogens such as Bacillus thuringiensis and Beauveria bassiana are also described in the context of host–pathogen interaction. Finally, the plasticity of G. mellonella immune response influenced by abiotic and biotic factors is described.  相似文献   
7.
Fungal formulations are vital for effective biopesticide development. Good formulations help to optimise field efficacy, while poor formulations result in product failure. This study aimed to produce a hydrophobicity test that would be appropriate for fungal conidia produced to a commercial quality and determine relative hydrophobicity of fungi from four different genera by using laser diffraction. A particle size analyser was used to determine the hydrophobicity of: three Metarhizium acridum samples, M. anisopliae, Beauveria bassiana, Trichoderma stromaticum, T. harzianum, T. viride and Alternaria eichhorniae conidia by suspending the conidia in three different liquids: Shellsol T (a mineral oil), water and 0.05 % Tween 80. Hydrophobicity was determined by the size of the particles formed in each of the liquids. All the Metarhizium samples were the most hydrophobic followed by B. bassiana and A. eichhorniae. The Trichoderma samples were the least hydrophobic. As a comparison, a phase exclusion assay and a salt-mediated aggregation and sedimentation (SAS) test were performed. It was not possible to get a reliable reading for the B. bassiana, A. eichhorniae and T. viride samples using the phase exclusion assay. The addition of salt in the SAS test did not affect the rate of sedimentation. It was hypothesised that conidia size affected the results of the SAS test that made A. eichhorniae the most hydrophobic conidia. Particle size analysis (PSA) was a more accurate test for comparing fungi from difference genera compared to the SAS test and phase exclusion assay. PSA was also used to test three emulsions and demonstrated that different formulations had an effect on particle size.  相似文献   
8.
We demonstrate the effectiveness of three inoculation methods (foliar spray, seed immersion and root immersion) in establishing fungal the entomopathogen Beauveria bassiana as an endophyte in tobacco, corn, wheat and soybean. Colonisation of leaves by B. bassiana was assessed 7, 14, 21 and 28 days post-inoculation. There were significant differences (p < 0.001) in endophytic colonisation among the different inoculation techniques.  相似文献   
9.
采用PCR-SSCP方法检测猪胰岛素样生长因子2 (insulin-like growth factor 2,IGF2)基因外显子3多态性,分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应.根据猪IGF2基因的DNA序列(AY044828)设计引物,结果在其扩增片段上检测到多态性,对纯合子进行测序,发现IGF2-ex3-A36T和IGF2-ex3-G109A两个多态性位点,并且这2个多态性位点完全连锁,检测到3种基因型(A36A/G109G,A36T/G109A 和 T36T/A109A).统计结果表明,基因型在各品种中分布不一致,长白猪和大白猪与莱芜猪、大薄莲猪、沂蒙黑猪和里岔黑猪比较基因型分布差异极显著(P<0.01);其它猪种间基因型分布差异均不显著(P>0.05).固定效应模型分析结果表明,初生重和背膘厚基因型间差异显著(P<0.05),而断奶重和6月龄重基因型间差异不显著(P>0.05).最小二乘分析结果表明,A36A/G109G基因型个体同A36T/G109A和 T36T/A109A基因型个体比较初生重和背膘厚的差异显著(P<0.05),3种基因型初生重的大小排列顺序为A36A/G109G < A36T/G109A < T36T/A109A,背膘厚的大小排列顺序为A36A/G109G > A36T/G109A >T36T/A109A.因此,推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择,将可以改善猪肉品质,加快猪的育种进程.  相似文献   
10.
箬叶多糖的分离纯化及其理化性质的研究   总被引:20,自引:0,他引:20  
采用分步提取的方式从中药箬叶中分离得到8种多糖组分:酸性杂多糖FS、FE、FⅠ,β-D-葡萄糖醛酸聚糖FⅡ和四种半纤维素多糖α-D-木聚糖FⅢ-a、FⅢ-b、FⅣ-a及FⅣ-b.紫外光谱、红外光谱、凝胶色谱、元素分析等结果表明8种箬叶多糖为纯品.并采用纸层析,气相色谱分析确定其单糖组成.采用高效凝胶渗透色谱GPC法测定了4种箬叶多糖FE、FⅠ、FⅢ-a及FⅣ-a的重均分子量Mw、数均分子量Mn,均为大分子,分子量分布较窄,纯度较高.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号