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91.
在虚拟的网络世界中, 构建网络道德, 很大程度上要依赖于网络传播者的道德和素质。本课题试图通过探讨网络传播者的思想道德素质状况, 分析如何加强传播者的网络道德教育, 提升其道德自律能力, 从而促进网络道德体系和网络文明建设。 相似文献
92.
Francis Obala Samira A Mohamed Titus Obidi Magomere Sevgan Subramanian 《Pest management science》2023,79(12):5312-5320
BACKGROUND
Maize production in Africa is hindered by a myriad of biotic challenges, key among them being invasive and native lepidopteran stemborers. Recent invasion of the continent by fall armyworm, Spodoptera frugiperda, has further exacerbated the situation. Fortunately, Cotesia icipe was found to be very promising against S. frugiperda. However, the co-occurrence and interaction between S. frugiperda and the stemborers (Busseola fusca, Sesamia calamistis, and Chilo partellus) in maize agroecosystem may jeopardize the efficiency of C. icipe as a biocontrol agent of S. frugiperda. This study investigated the performance of C. icipe on S. frugiperda, Spodoptera littoralis and the stemborers. Specifically, the preference and acceptability of C. icipe to the host insects, the physiological suitability of the hosts for its development, and the effect of these hosts on the fitness parameters of the offspring were assessed.RESULTS
Cotesia icipe accepted all the tested hosts, albeit with higher preference for Spodoptera species than for stemborers under multiple-choice tests. Also, the highest parasitism of up to 97% was recorded on S. frugiperda compared with parasitism on the stemborers of 43% in B. fusca. Moreover, physiological suitability and fitness traits (except for per cent female offspring) varied with host species, again being optimal on Spodoptera species.CONCLUSION
Cotesia icipe demonstrated strong potential to control S. frugiperda in maize due to its high affinity for parasitization and developmental success in this host; and despite its non-specific parasitization, the presence of other hosts may not prevent its maximum control of S. frugiperda. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献93.
用透射电镜观察了短尾鮠精子细胞和精子的形态以及细胞核、拟染色体和线粒体等的结构变化规律。结果表明,随着精子细胞的发育,核质凝聚程度逐渐增强。精子细胞时期细胞器较丰富,到精子细胞后期,细胞器的形态和数量发生了较大变化。短尾鮠的精子具有椭圆的头部和复杂的中片;近侧中心粒和远侧中心粒靠近核的中央;鞭毛呈9+2轴丝结构,并具有由外膜折迭形成的波浪形的鳍状结构。 相似文献
94.
LG Bermúdez-Humarán P Chávez-Zamarripa A Guzmán-Velasco CH Leal-Garza R Montes de Oca-Luna 《Reproduction in domestic animals》2002,37(6):321-323
Molecular sexing is a rapid and safe procedure for bird sex determination. Two universal methods based on the amplification of a chromo‐helicase‐DNA‐Binding 1 (CHD) gene region, located in both sexual chromosomes (Z and W), have been established. We found that molecular sexing of Oreophasis derbianus failed by using these two procedures. One of them is based on a restriction site located in CHD1W gene but absent in CHD1Z. The DdeI restriction site, used successfully to determine gender in several bird species, was found to be lost because of nucleotide change in O. derbianus. This change created a new restriction site, NlaIII, that was successfully applied for sexing this endangered bird. 相似文献
95.
The commercial available diatomaceous earth Fossil Shield® and the neem product Neem Azal-T/S® are tested as single treatments and in combination as controls for the stored product pests Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). The diatomaceous earth, applied in concentrations of 0.5 g, 1 g and 2 g kg-1 rice, reduced numbers of surviving beetles significantly (over a period of 3 weeks). A single treatment with the neem product, in concentrations of 0.01 g, 0.1 g, 0.2 g and 1 g azadirachtin kg-1 rice, increased the mortality rate for both species significantly. The combination of neem and diatomaceous earth (1 g diatomaceous earth with 0.2 g or 1 g azadirachtin kg-1 rice) was more effective than the single treatment in reducing numbers of surviving beetles. 相似文献
96.
Kilburn JJ Murphy DP Titus M Payton ME Backues KA 《Journal of zoo and wildlife medicine》2011,42(1):65-68
Encephalomyocarditis virus (EMCV) is a pandemic virus that has caused mortality in numerous captive wildlife species worldwide. An experimental killed vaccine was created from two EMCV isolates associated with zoo animal mortality in the southern United States. The vaccine was tested for safety and efficacy in eleven llamas (Llama glama). All animals received an initial vaccination and a second booster vaccination 4 wk later. Serum antibody responses were monitored at initial vaccination and at 4 wks, 8 wk, 6 mo, and 12 mo postvaccination. Eight of the 11 llamas vaccinated experienced at least a 4-fold increase in serum antibody titers to EMCV. Antibody titers of those eight animals remained elevated above prevaccination levels when measured at 12 mo. The experimental killed EMCV vaccine tested may be a useful tool to prevent EMCV infection in llamas when given in 2 doses 4 wk apart, and then revaccinated or with antibody levels monitored annually thereafter. 相似文献
97.
J. A. M. Botermans M. S. Hedemann M. S. rhede‐Winzell CH. Erlanson‐Albertsson J. Svendsen L. Evilevitch S. G. Pierzynowski 《Journal of animal physiology and animal nutrition》2000,83(1)
The effect of night feeding and feeding frequency on exocrine pancreatic secretion was studied in five chronically catherized growing pigs (16 to 31 kg). Feeding during the night (2200 to 2400 h) as compared to the day (1000 to 1200 h) tended to stimulate cholesterol ester lipase activity and tended to lower the colipase : lipase ratio in the pancreatic juice, but no effect on volume output, protein output and the activities of trypsin, chymotrypsin, amylase, lipase and colipase could be demonstrated. Feeding 12 small meals between 0800 and 2000 h as compared to one large meal (1000 to 1200 h) daily, altered the pattern of exocrine pancreatic secretion, tended to stimulate protein output by 44 %, chymotrypsin activity by 29 % and lipase activity by 46 %. These observations strengthened the theory that exocrine pancreatic secretion is partly regulated by feed intake per se and does not only depend on the amount of feed consumed. Feeding 12 small meals versus one large meal, compared at the same total daily feed intake, lowered the colipase : lipase ratio by 32 %. It can be concluded that feed intake pattern affected exocrine pancreatic secretion. 相似文献
98.
99.
CH. Iben 《Journal of animal physiology and animal nutrition》1999,82(2-3):66-79
Introduction Carnitine (trimethyl-γ-amino-β-hydroxybutyrate; molecular weight 161 g) is not only essential for the transport and utilization of long-chain fatty acids, it also occurs as a medium and short-chain ester and serves as an acetyl and acyl pool. Short-term muscle exercise causes an increase of acetyl-carnitine levels in the serum and in the liver. It prevents the accumulation of acyl-coenzyme A (CoA) and provides the organism with CoA by producing acetyl-carnitine from acetyl-CoA. Human muscle tissue contains approximately 10 μmol CoA/kg, whereas carnitine levels range between 2000 and 5000 μmol/kg. 相似文献
100.
Fibrin–alginate hydrogel supports steroidogenesis,in vitro maturation of oocytes and parthenotes production from caprine preantral follicles cultured in group 下载免费PDF全文
IR Brito GM Silva AD Sales CH Lobo GQ Rodrigues RF Sousa AAA Moura CEM Calderón M Bertolini CC Campello J Smitz JR Figueiredo 《Reproduction in domestic animals》2016,51(6):997-1009
This study aimed to establish a culture system that improves the in vitro development of caprine preantral follicles. In a first experiment, follicles were encapsulated as a single unit per bead and cultured singly or in groups or with five follicles in the same alginate (ALG) bead for 18 days. In a subsequent experiment, the “five follicles per bead” design was chosen to culture in ALG, fibrin–alginate (FA) or hyaluronate (HA) for 18 days. In a third experiment, we chose the five follicles per bead in FA to culture for 30 days. The culture set‐up of five follicles per ALG bead increased antrum formation and follicle diameter compared to the other culture designs (p < .05). Moreover, under this condition, 44.44% of the oocytes from in vitro cultured preantral follicles reached meiotic resumption. A significant increase of follicle diameter occurred in attachment system and FA (p < .05), but the ALG condition reached the highest among all groups on day 18 (p < .05). Follicles encapsulated in matrix produced more estradiol and progesterone than attachment system (p < .05). The expression of MMP‐9 mRNA was higher in FA than in other groups (p < .05) and similar to antral follicles from in vivo control (p > .05). Only FA group resulted in oocytes matured. After 30 days, oocytes from preantral follicles in vitro grown in FA developed to eight‐cell parthenotes. In conclusion, a culture system using FA supported the development of caprine preantral follicles cultured in group and included in the same bead of hydrogel, improving the oocyte maturation and producing parthenotes. 相似文献