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621.
The influence of soybean meal (SBM) on the growth and feed utilization of juvenile sutchi catfish (Pangasianodon hypophthalmus, Sauvage, 1878) was investigated. Eight isonitrogenous (300 g kg?1 CP) and isoenergetic (18 MJ kg?1) diets were formulated incorporating Argentine SBM to replace fish meal at 0, 150, 300, 450, 600, 750, 900 and 1000 g kg?1 dietary protein. Each diet was fed to three replicate groups of fish with an initial weight 6.0–6.2 g for twelve weeks. Growth performance decreased, and feed utilization was worsened with the increase in SBM inclusion in the diets. Final weight and relative growth rate (RGR) of fish fed control diet (0 SBM) were significantly higher than those fed test diets (P < 0.05). However, there were no significant differences in the final weight and RGR between the fish fed on 15 SBM, 30 SBM, 45 SBM and 60 SBM diets. Specific growth rate of fish fed 0 SBM, 15 SBM, 30 SBM and 45 SBM diets was significantly higher than those fed other diets. Feed conversion ratio of fish fed 0 SBM, 15 SBM, 30 SBM, 45 SBM and 60 SBM diets was significantly lower than those fed other diets (P < 0.05). The dry matter and protein digestibility were lesser in all the diets in comparison with the control diet. Hepatosomatic index and viscerosomatic index increased with increasing SBM in diet. This present trial indicated that fish meal can be replaced by SBM in the diet of juvenile sutchi catfish only up to 45% of fish meal protein without any adverse effect on growth, feed utilization and body composition. 相似文献
622.
Age‐0 blue catfish habitat use and population demographics in the middle Mississippi River 下载免费PDF全文
The demographics (e.g. hatch time, growth and mortality) and habitat (macrohabitat and mesohabitat) use of age‐0 blue catfish Ictalurus furcatus (Lesueur) were evaluated in the un‐impounded reach of the middle Mississippi River during 2003–2010. Each year, island complexes and adjacent main river habitats were trawled, and 7,373 age‐0 blue catfish (10–144 mm total length) were collected. Blue catfish hatch timing varied slightly across years and generally began in June and ended in August. Age‐0 blue catfish growth rates and instantaneous mortality rates differed among years. Catch rates of age‐0 blue catfish were highest in side channels and around islands, whereas main channel habitats were infrequently occupied. Regarding mesohabitat use, age‐0 blue catfish frequently occupied low velocity areas (i.e. 0.3–0.4 m/s) of shallow depth (i.e. 1–4 m) and sand substratum. This study has provided insight into age‐0 blue catfish population dynamics and has highlighted the importance of specific habitat characteristics in large rivers that may aid in recruitment of this species. 相似文献
623.
An experiment was performed to evaluate the efficacy of potassium permanganate (KMnO4 ) as a prophylactic and therapeutic treatment of an experimental subacute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus . Fish were cutaneously abraded and divided into five treatment groups: (i) challenged by waterborne exposure to F. columnare and not treated with KMnO4 (positive control), (ii) challenged and simultaneously treated with KMnO4, (iii) challenged and treated with KMnO4 at 1, 6 and 9 days post-challenge, (iv) not challenged and treated with KMnO4 at 1, 6 and 9 days post-challenge (first negative control) and (v) not challenged and not treated (second negative control). The dosing of KMnO4 was 2.0 mg L−1 above the potassium permanganate demand for 2 h duration. The survival of the group challenged and simultaneously treated with KMnO4 (99%) was significantly higher than the positive control (78%) and was not significantly different from the negative control groups. The challenged fish treated with KMnO4 post-challenge had 7% higher survival than the positive control (85% compared with 78%), but that difference was not statistically significant. The results demonstrate that KMnO4 has a clear prophylactic value but probably a marginal therapeutic value once the infection has established. 相似文献
624.
黄颡鱼对生态环境的适应能力较强,通过驯化可摄食人工配合饲料。2004年笔者在河南省郑州市沟赵镇水产养殖场进行了黄颡鱼规模化养殖高产课题试验,取得了较高的经济效益,现将试验情况总结如下。1试验条件1.1池塘条件试验池塘共9口,每口池塘面积均为0.67 hm2,水深2.0~2.5 m,水源充足,水质符合渔业用水水质标准。每个池塘配备6 kW叶轮式增氧机1台。1.2池塘清整投放鱼种前约15 d以1500 kg/hm2的生石灰或375 kg/hm2的漂白粉清塘消毒,7 d后投施3000~4500 kg/hm2的有机肥料,待水体中大量出现浮游动物后投放鱼种。2试验方法2.1鱼种放养鱼种购自湖北… 相似文献
625.
细胞因子信号传导抑制因子(SOCS)是JAK/STAT信号通路中细胞因子信号受体的重要抑制因子。为探究SOCS在鱼类免疫应答过程中的作用,本研究以杂交黄颡鱼“黄优1号”及其母本黄颡鱼和父本瓦氏黄颡鱼为研究对象,克隆了杂交黄颡鱼“黄优1号”3个免疫相关基因(SOCS1、SOCS2和SOCS3),并对其生物信息学进行了比较分析;采用qRT-PCR技术研究了SOCS1、SOCS2和SOCS3基因分别在3种黄颡鱼感染嗜水气单胞菌和鮰爱德华氏菌后的表达模式。结果显示,杂交黄颡鱼“黄优1号”SOCS1、SOCS2和SOCS3基因的全长分别为561、735和672 bp,分别编码186、244和223个氨基酸,其预测的蛋白结构均含有保守的SH2结构域和SOCS盒。黄颡鱼、瓦氏黄颡鱼和杂交黄颡鱼“黄优1号”SOCS1、SOCS2和SOCS3基因的表达在被检的8个不同组织中呈现组织特异性。在两种致病菌感染后,杂交黄颡鱼“黄优1号”及其双亲的SOCS1、SOCS2和SOCS3基因在肝、鳃和头肾组织的表达量均在前24 h显著升高,随后逐渐恢复至正常水平。此外,鮰爱德华氏菌感染后,杂交黄颡鱼“黄优1号” SOCS1、SOCS2和SOCS3基因的表达量显著高于双亲,表现出较双亲更强的免疫调节能力且具有病原特异性。该结果为进一步解析黄颡鱼SOCS家族免疫防御调控机制提供了参考依据。 相似文献