全文获取类型
收费全文 | 331篇 |
免费 | 19篇 |
国内免费 | 37篇 |
专业分类
农学 | 4篇 |
8篇 | |
综合类 | 70篇 |
农作物 | 1篇 |
水产渔业 | 18篇 |
畜牧兽医 | 282篇 |
园艺 | 2篇 |
植物保护 | 2篇 |
出版年
2024年 | 4篇 |
2023年 | 8篇 |
2022年 | 13篇 |
2021年 | 25篇 |
2020年 | 25篇 |
2019年 | 21篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 16篇 |
2013年 | 20篇 |
2012年 | 20篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 18篇 |
2008年 | 15篇 |
2007年 | 13篇 |
2006年 | 14篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1956年 | 1篇 |
排序方式: 共有387条查询结果,搜索用时 15 毫秒
91.
Anne-Claire D. Limon Hiran M. L. W. Patabendige Ala Azhari Xingmin Sun Dennis E. Kyle Nerida G. Wilson Bill J. Baker 《Marine drugs》2022,20(9)
Chemical investigation of an Antarctic deep-water octocoral has led to the isolation of four new compounds, including three illudalane sesquiterpenoids (1–3) related to the alcyopterosins, a highly oxidized steroid, alcyosterone (5), and five known alcyopterosins (4, 6–9). The structures were established by extensive 1D and 2D NMR analyses, while 9 was verified by XRD. Alcyopterosins are unusual for their nitrate ester functionalization and have been characterized with cytotoxicity related to their DNA binding properties. Alcyopterosins V (3) and E (4) demonstrated single-digit micromolar activity against Clostridium difficile, an intestinal bacterium capable of causing severe diarrhea that is increasingly associated with drug resistance. Alcyosterone (5) and several alcyopterosins were similarly potent against the protist Leishmania donovani, the causative agent of leishmaniasis, a disfiguring disease that can be fatal if not treated. While the alcyopterosin family of sesquiterpenes is known for mild cytotoxicity, the observed activity against C. difficile and L. donovani is selective for the infectious agents. 相似文献
92.
Antimicrobial Susceptibility Patterns of Clostridium difficile Isolates from Family Dairy Farms 下载免费PDF全文
A significant risk factor for developing Clostridium difficile infection (CDI) in humans and animals is associated with the antimicrobial use. It has often been hypothesized that farm animals could be the source for human infection with Clostridium difficile (CD). In the European Union, family‐run dairy farms are the predominant farming model, which are more interlinked within the community compared to large‐scale intensive dairy or beef farms. Therefore, it is important to investigate antimicrobial susceptibility patterns of CD in such environment. A total of 159 CD isolates from 20 family dairy farms were tested with a customized broth microdilution plate for their antimicrobial resistance. Seventeen antimicrobials were selected (amoxicillin, ceftriaxone, clindamycin, daptomycin, erythromycin, fusidic acid, imipenem, levofloxacin, linezolid, metronidazole, moxifloxacin, oxacillin, rifampicin, tetracycline, tigecycline, trimethoprim/sulfamethoxazole and vancomycin), which are commonly used for treatment of CDI in veterinary and human medicine, or were previously applied in CD epidemiological studies. Antimicrobials, which are used for treatment of CDI in humans (metronidazole, vancomycin, fusidic acid, tigecycline, linezolid) inhibited CD growth in vitro. Most CD isolates were resistant to erythromycin (93.1%), daptomycin (69.2%) and clindamycin (46.5%). High multiple‐resistance was found in CD ribotype 012 (n = 5, 100%), some CD SLO 060 (n = 4, 25%) and one CD 033 (n = 1, 1.1%). High multiple‐resistance in this study was linked with CD ribotypes and not with the origin of CD. The low prevalence of these ribotypes (6.3%; 10/159) indicates that family‐run dairy farms are an unlikely source of CD with multiple‐resistance to antimicrobials. 相似文献
93.
94.
OBJECTIVE: To compare the ability of a new single-dose botulinum vaccine containing a non-mineral oil adjuvant with a single dose of a conventional botulinum vaccine product to produce antibody to Clostridium botulinum types C and D in cattle in Northern Australia. DESIGN AND PROCEDURE: One hundred and fifty Brahman steer weaners were randomly divided into two groups receiving either a single dose of CSL Bivalent Botulinum vaccine or Websters Singvac. Blood samples were collected at 0, 8 and 24 weeks and tested by antibody ELISA. The final samples were also tested by the toxin neutralisation test, to test titres of neutralising antibody. RESULTS: Six months after inoculation, cattle vaccinated with Websters Singvac had ELISA antibody response twice that of CSL conventional product. However, this difference was only evident for neutralising antibody to type C botulinum toxin. Both products produced similar titres of type D neutralising antibody after a single dose. CONCLUSION: Websters' Singvac produces a greater neutralising antibody response to type C botulism upon single inoculation than a conventional vaccine. The product produces an equivalent neutralising antibody response to type D. 相似文献
95.
There is little information on bacteria that have the potential to cause disease in reindeer husbandry. In this project, faecal samples from 35 free-ranging or corralled reindeer, adults and calves, that died in the winter of 2000 in northern Norway, were examined for the occurrence of Campylobacter spp., Clostridium perfringens, Listeria spp., Salmonella spp. and Yersinia spp. to evaluate the role of these microrganisms in loss and mortality in reindeer husbandry. In addition, 31 of these samples were examined for the occurrence of bacteria producing shigatoxin-1 and 2. C. perfringens was isolated in 20 (57.1%) of the faecal samples. In the free-ranging reindeer, 44% were positive carriers of C. perfringens and 90% of the corralled ones were positive for C. perfringens. In addition, the gene encoding for shigatoxin-1 was detected in one of the samples derived from a corralled reindeer. The other bacteria investigated were not found. Shigatoxin-1-producing bacteria were isolated for the first time from reindeer in Norway. However, no correlation between C. perfringens or shigatoxin-1-producing bacteria and mortality in the reindeer could be established. 相似文献
96.
Marlier D Dewrée R Lassence C Licois D Mainil J Coudert P Meulemans L Ducatelle R Vindevogel H 《Veterinary journal (London, England : 1997)》2006,172(3):493-500
Epizootic rabbit enteropathy (ERE), a highly lethal (30-80% mortality) disease of broiler rabbits aged 6-14 weeks, first appeared in 1997 in French intensive enclosed rabbitries and is of unknown aetiology. Bacteriological, virological and parasitical examination of the intestinal contents of rabbits that had died either in spontaneous field cases or after experimental reproduction of ERE, were undertaken in an attempt to identify infectious agents that may play a role in the disease. Two bacterial strains, Clostridium perfringens and non-enteropathogenic Escherichia coli were repeatedly isolated at high faecal counts from naturally infected animals. In field cases, a correlation between typical gross lesions of epizootic enteropathy and the presence of the alpha toxin of Cl. perfringens was observed (P<0.0001; Chi-squared test). Although attempts to reproduce the disease by inoculation with different pools of cultivable bacterial strains failed, the disease was successfully reproduced by inoculation with one French and two Belgian samples of caecal contents. 相似文献
97.
Equine grass sickness (EGS; equine dysautonomia) is a polyneuronopathy affecting both the central and the peripheral nervous systems of horses. As the name implies, EGS almost exclusively affects grazing horses, resulting in the development of a characteristic array of clinical signs, most of which can be attributed to neuronal degeneration in the autonomic and enteric nervous systems. Varying disease severities occur, largely determined by the extent of neuronal degeneration in the myenteric and submucous plexuses of the enteric nervous system. Extensive neuronal degeneration, as seen in acute and subacute forms of EGS, results in intestinal dysmotility, the severity of which is incompatible with survival. In comparison, a proportion of chronic forms of EGS, characterised by less severe neuronal degeneration, will survive. Despite extensive research efforts since EGS was first reported over 100 years ago, the precise aetiology remains elusive. This article reviews much of the scientific literature on EGS, covering epidemiology, pathology, diagnosis, treatment and aetiological hypotheses. 相似文献
98.
DU Jige ZHU Zhen XU Zhongqing LI Qianlin YAO Wensheng LI Qihong YIN Chunsheng YANG Liu FU Lizhi CHEN Xiaoyun LIU Ying XUE Qi 《畜牧兽医学报》1956,51(11):2794-2801
This study was conducted to obtain the Clostridium perfringens β toxin (CPB) derivative and to evaluate its virulence and immunoprotection. Based on the known sequence, four amino acid mutations, R212E, L268G, Y266A and W275A, were introduced into the gene of Clostridium perfringens CPB. Meanwhile, genes of Th cell and N-terminal of flagellin were added to 5' of the CPB gene, respectively. Then the gene GTFNCPBm4 was optimized and synthesized, and was subsequently cloned into the prokaryotic expression vector pET-30a (+) for expression and purification to get the recombinant protein, rTFNCPBm4. Reactivity of rTFNCPBm4with antiserum of Clostridium perfringens type C crude toxins was detected by Western blot. Meanwhile, the toxicity of rTFNCPBm4 to mice was evaluated. According to the method prescribed in Chinese Veterinary Pharmacopoeia (2015), rabbits were immunized with rTFNCPBm4 to prepare antiserum and detect the neutralizing titer against Clostridium perfringens type C crude toxins. Results showed that rTFNCPBm4 was presented predominantly in an insoluble form (inclusion bodies), and it could react with the antiserum of Clostridium perfringens type C crude toxins. rTFNCPBm4 with an injection volume of 50 μg was still not fatal to mice. Sera from rabbits immunized with rTFNCPBm4can neutralize 10-20 mouse minimum lethal doses (MLD) of Clostridium perfringens type C crude toxins after twice immunization. Moreover, rabbits immunized with rTFNCPBm4 can fully resist 1 rabbit MLD of Clostridium perfringens type C crude toxins challenge, whereas all of the rabbits died (4/4) in the control groups. These data suggest that rTFNCPBm4 is a potential vaccine candidate for the subunit vaccine of Clostridium perfringens type C. 相似文献
99.
本研究旨在获得腐败梭菌无毒重组α毒素,并评价其免疫保护性。对已知的腐败梭菌α毒素编码基因进行优化设计和人工合成,获得了缺少第212-222位共11个氨基酸编码序列的基因片段(GCSAΔ11)。将该基因克隆至原核表达载体pET-30a(+)中进行表达与纯化。利用Western blot方法检测获得的重组α毒素(rCSAΔ11)与腐败梭菌天然毒素抗血清的反应性,并采用小鼠检测其毒力。随后,以rCSAΔ11制备疫苗免疫家兔,按照《中华人民共和国兽药典》(2015年版)规定的方法检测家兔血清的中和抗体效价。结果表明,rCSAΔ11可溶表达比例可达46%,且能与腐败梭菌天然毒素抗血清反应。进一步的试验结果显示,rCSAΔ11丧失了对小鼠的毒力,0.1 mL的一免兔血清可中和8~12个小鼠最小致死量(MLD)的腐败梭菌天然毒素;二免兔血清可中和32~45个小鼠MLD的腐败梭菌天然毒素。1个家兔MLD的腐败梭菌天然毒素攻毒后,对照组家兔4/4死亡,免疫组家兔得到了100%(4/4)的保护。综上表明,无毒性的rCSAΔ11保留了良好的免疫保护性,从而为腐败梭菌病基因工程亚单位疫苗的研制提供了重要的试验数据。 相似文献
100.