全文获取类型
| 收费全文 | 138篇 |
| 免费 | 33篇 |
| 国内免费 | 22篇 |
专业分类
| 农学 | 9篇 |
| 6篇 | |
| 综合类 | 35篇 |
| 水产渔业 | 142篇 |
| 畜牧兽医 | 1篇 |
出版年
| 2024年 | 1篇 |
| 2023年 | 2篇 |
| 2022年 | 3篇 |
| 2021年 | 1篇 |
| 2020年 | 3篇 |
| 2019年 | 5篇 |
| 2018年 | 6篇 |
| 2017年 | 16篇 |
| 2016年 | 15篇 |
| 2015年 | 10篇 |
| 2014年 | 13篇 |
| 2013年 | 11篇 |
| 2012年 | 6篇 |
| 2011年 | 10篇 |
| 2010年 | 13篇 |
| 2009年 | 17篇 |
| 2008年 | 8篇 |
| 2007年 | 7篇 |
| 2006年 | 6篇 |
| 2005年 | 6篇 |
| 2004年 | 5篇 |
| 2003年 | 8篇 |
| 2002年 | 6篇 |
| 2001年 | 5篇 |
| 2000年 | 7篇 |
| 1999年 | 1篇 |
| 1995年 | 1篇 |
| 1994年 | 1篇 |
排序方式： 共有193条查询结果，搜索用时 15 毫秒
31.
Tomoki Hashimoto Katsuya Hyodoh Takuma Hirose Satoshi Nishikawa Toshiya Katano Shin-ichi Nakano 《Aquaculture International》2008,16(4):309-318
In the pearl cultivation farms of the Ehime Prefecture, Japan, mass mortalities of the pearl oyster Pinctada fucata have occurred since 1994. The occurrences of mass mortality roughly coincided with a shift of the dominant phytoplankton
from Skeletonema and Chaetoceros to Chaetoceros and Nitzschia all of which belong to Bacillariophyceae. Hence, we evaluated Nitzschia, together with Chaetoceros and Isocrysis, as food for the oyster. Wet weights, lengths, widths, glycogen contents, and growth rates in terms of wet weight of the
oysters in all the feeding treatments were significantly higher than those in the non-feeding treatment. The highest glycogen
content (2.34%) and growth rate (2.21 g month−1) were found in the Chaetoceros treatment. Growth rate in the Isocrysis treatment (1.63 g month−1) was also high, although glycogen content in this treatment (0.41%) was low. In the Nitzschia treatment, growth rate of the oyster (0.94 g month−1) was the lowest and glycogen content (0.83%) was also low relative to that in the Chaetoceros treatment. Chlorophyll a concentration in fecal pellets was lowest in the Nitzschia treatment (<2.7 μg mg−1), suggesting more complete digestion of Nitzschia by the oyster. Thus, Nitzschia was edible and digestible but not assimilated by P. fucata. We propose the following scenario for the relationship between Nitzschia dominance and mass mortality. When Nitzschia dominates in a culture area, the physiological condition of P. fucata deteriorates due to low assimilation of Nitzschia by the oyster, followed by susceptibility of the oyster to infection by agents lethal to the oyster. 相似文献
32.
B淋巴细胞瘤-2(B-cell lymphoma, Bcl-2)基因作为一种重要的细胞凋亡调控基因,在内源性细胞凋亡通路中发挥着重要的调控作用。实验利用c DNA末端快速扩增(RACE)技术克隆获得PmBcl-2-like基因cDNA全长序列,并对其序列进行生物信息学分析;利用实时定量PCR(qPCR)技术分析了PmBcl-2-like在马氏珠母贝不同组织、不同发育时期以及不同免疫刺激后的表达水平。结果显示,PmBcl-2-like cDNA全长为2 180 bp,开放阅读框长度为1 650 bp,共编码549个氨基酸,分子量为21.62 ku;结构域预测分析表明PmBcl-2-like含有Bcl-2家族典型的BH1-4结构域;多序列比对以及进化树构建结果表明,PmBcl-2-like与其他物种的相似度较高,保守性较强;荧光定量结果表明PmBcl-2-like在马氏珠母贝8个组织中均有表达,在鳃中表达量最高,其次为性腺,表达量最低为中央膜区;在胚胎期表达量较高,受精卵时期表达量最高。机体受到脂多糖(LPS)刺激后,相对表达量在24 h达到最高,72 h降到最低,最高约为最低的2.5倍;肽聚糖(PGN)刺激后,相对表达量在6 h达到最高,48 h降到最低,最高约为最低的7.28倍;聚肌胞苷酸(Poly:IC)刺激后,相对表达量在3 h达到最高,12 h降到最低,最高约为最低的6.49倍。研究表明,PmBcl-2-like可能在马氏珠母贝发育和免疫防御反应中担任着重要的角色。 相似文献
33.
Detection of Minchinia occulta in samples of pearl oysters Pinctada maxima infected by Haplosporidium hinei 总被引：1，自引：1，他引：0
D Bearham ZB Spiers SR Raidal JB Jones PK Nicholls 《Australian veterinary journal》2009,87(11):430-437
Objective To determine if juvenile pearl oysters ( Pinctada maxima ) infected with Haplosporidium hinei are also infected with another haplosporidian parasite, Minchinia occulta .
Design Archived samples of pearl oysters infected with H. hinei were examined using polymerase chain reaction (PCR) assays and in situ hybridisation (ISH) to analyse and identify haplosporidians. A 144-bp and 220-bp region of Minchinia DNA were targeted by PCR and amplified DNA from formalin-fixed H. hinei -infected pearl oyster samples was sequenced. A 25-bp oligonucleotide probe targeting a variable section of the parasite's small subunit rRNA gene was used in ISH.
Results The results of DNA-based diagnostic assays supported each other. The sequences obtained by PCR were found to be almost identical to M. occulta from rock oysters and the ISH assay demonstrated infection with M. occulta in affected pearl oysters. ISH indicated a prevalence of infection of 26.7% in one of the previous outbreaks.
Conclusion Pearl oyster spat are susceptible to infection by a Minchinia parasite, most likely M. occulta , which was recently identified in rock oysters within the pearl-producing zones of Western Australia and is associated with mortalities of up to 80% in this species. The occurrence of haplosporidian co-infections in pearl oysters suggests the immunocompetence of juvenile oysters may be an important factor in preventing infection and therefore preventing mortalities such as those occurring in the recent outbreaks of pearl oyster oedema disease. 相似文献
Design Archived samples of pearl oysters infected with H. hinei were examined using polymerase chain reaction (PCR) assays and in situ hybridisation (ISH) to analyse and identify haplosporidians. A 144-bp and 220-bp region of Minchinia DNA were targeted by PCR and amplified DNA from formalin-fixed H. hinei -infected pearl oyster samples was sequenced. A 25-bp oligonucleotide probe targeting a variable section of the parasite's small subunit rRNA gene was used in ISH.
Results The results of DNA-based diagnostic assays supported each other. The sequences obtained by PCR were found to be almost identical to M. occulta from rock oysters and the ISH assay demonstrated infection with M. occulta in affected pearl oysters. ISH indicated a prevalence of infection of 26.7% in one of the previous outbreaks.
Conclusion Pearl oyster spat are susceptible to infection by a Minchinia parasite, most likely M. occulta , which was recently identified in rock oysters within the pearl-producing zones of Western Australia and is associated with mortalities of up to 80% in this species. The occurrence of haplosporidian co-infections in pearl oysters suggests the immunocompetence of juvenile oysters may be an important factor in preventing infection and therefore preventing mortalities such as those occurring in the recent outbreaks of pearl oyster oedema disease. 相似文献
34.
采用酶技术,利用珍珠养殖场开珠后的废弃物－－马氏珍珠贝肉,研制珍珠贝肉营养液。结果显示,采用枯草杆菌中性蛋白酶和风味酶Ｆｌａｖｏｕｒｙｚｍｅ联合水解马氏珍珠贝肉的效果最好,通过正交试验法确定了酶法水解的最佳工艺条件是：温度５０℃,时间５ｈ,ｐＨ６．５,枯草杆菌中性蛋白酶和Ｆｌａｖｏｕｒｙｚｍｅ的添加量分别为０．６％和０．２５％。对营养液的营养价值进行分析评价,营养液中蛋白质达到７３．６ｍｇ／ｍＬ, 相似文献
35.
人工神经网络优化酶法制备马氏珠母贝
低聚肽的工艺研究 总被引：1，自引：0，他引：1
以马氏珠母贝全脏器为原料,采用胃蛋白酶、胰蛋白酶以及胰凝乳蛋白酶模拟消化道酶解的方式制备低聚肽,先通过胃蛋白酶酶解获得初产物,在此基础上利用人工神经网络对胰蛋白酶及胰凝乳蛋白酶的双酶酶解过程进行模拟预测,对其酶解工艺进行优化.试验结果表明,通过人工神经网络预测获得小肠消化蛋白酶双酶酶解的优化工艺条件为:复合酶添加量4 500 U/g(m 胰蛋白酶∶m胰凝乳蛋自酶=6∶1)、料水比1∶2(W/V)、酶解时间3.5 h,在此条件下制备的低聚肽(200～2 000 u)得率达55％以上.通过优化的工艺条件制备的低聚肽可获得较高的得率,能够为马氏珠母贝全脏器低聚肽的开发利用奠定基础. 相似文献
36.
在室内养殖条件下研究了术前限食处理对马氏珠母贝血淋巴细胞密度、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、溶菌酶(LSZ)、酸性磷酸酶(ACP)和碱性磷酸酶(AKP)活性的影响。实验设置每天投喂一次和两天投喂一次两个处理组,每天投喂两次为对照组,分别在实验开始和第1、2、3和4周取样检测血淋巴免疫功能。结果显示:限食1周后,马氏珠母贝血细胞密度、SOD、CAT、LSZ、ACP和AKP等酶活性均随限食程度的增加呈下降趋势,2个限食处理组的免疫参数较对照组明显下降,并表现出显著性差异(P0.05),两天投喂一次处理组的各项免疫机能均显著低于对照组,且这种趋势一直延续至第4周。据此推断,限食可以显著降低插核手术贝的生理机能和免疫活性,为马氏珠母贝育珠术前处理提供理论依据。 相似文献
37.
38.
马氏珠母贝杂交与自繁后代及企鹅珍珠贝间同工酶差异分析 总被引：4，自引：0，他引：4
利用垂直板状聚丙烯酰胺梯度凝胶电泳分离技术,对马氏珠母贝（PinctadamartensiiD.）和企鹅珍珠贝（Pteria penguinR.）的鳃、后闭壳肌2种组织的5种同工酶进行检测,以比较珍珠贝及马氏珠母贝不同养殖群体酶谱差异.分析表明,不同种间的个体酶谱表型有稳定的差异,筛选出的鳃组织过氧化物歧化酶（SOD）、酯酶（EST）及闭壳肌组织的苹果酸脱氢酶（MDH）、苹果酸酶（ME）、葡萄糖-6-磷酸脱氢酶（G6PDH）等同工酶,具有种特异性,这些酶带清晰稳定,可作为区别种的分子标记.马氏珠母贝群间杂交与群内自繁群体中,不同个体的酶谱表型比较相似,但自繁后代群体酶谱的相似程度更高,位点Sod-2杂合度仅为0.05、近交系数高达0.857,而杂交后代位点杂合度为0.55、F=-0.173,在不同种组织中,两群体间SOD同工酶均存在稳定差异,这种与亲缘关系相关联的酶谱表型,作为蛋白分子标记,可望应用于珠母贝品种改良及品系鉴定上. 相似文献
39.
对合浦珠母贝12个全同胞家系的生长性状和才女虫寄生病的感染情况进行比较分析,结果显示:筛选出的快速生长家系F10、F11、F3和F12与生长最慢的家系F7相比,壳高分别大16.01％、14.93％、10.51％和10.16％,体质量分别重35.72％、28.02％、25.98％和17.61％.筛选出的抗病家系F8、F9、F11和F10,其才女虫寄生病的总感染率与感染最高的家系F3相比,分别降低了48％、34％、27％和23％,表明这4个家系初步提高了合浦珠母贝抗才女虫寄生病的能力.筛选出的快速生长家系和抗病家系可作为选育的核心育种家系,为培育生长速度快和抗才女虫寄生病的合浦珠母贝新品系奠定良好的基础. 相似文献
40.
以马氏珠母贝全脏器为原料提取，纯化后所得的珠母贝糖胺聚糖PG－3－2，经醋酸纤维素薄膜电泳显示其迁移率相对接近于6－硫酸钦骨素（C－6－S），红外光谱类似于C－6－S。抗肿瘤试验结果显示：PG2－3－2对体内S180肉瘤和艾氏腹水癌可显著增敏临床抗癌药的抑瘤作用，抑瘤率分别达61．96％与46．3％。并有抗凝血作用。 相似文献