全文获取类型
收费全文 | 2913篇 |
免费 | 241篇 |
国内免费 | 172篇 |
专业分类
林业 | 132篇 |
农学 | 118篇 |
基础科学 | 10篇 |
143篇 | |
综合类 | 717篇 |
农作物 | 136篇 |
水产渔业 | 241篇 |
畜牧兽医 | 1244篇 |
园艺 | 53篇 |
植物保护 | 532篇 |
出版年
2024年 | 28篇 |
2023年 | 59篇 |
2022年 | 118篇 |
2021年 | 146篇 |
2020年 | 158篇 |
2019年 | 168篇 |
2018年 | 99篇 |
2017年 | 119篇 |
2016年 | 139篇 |
2015年 | 121篇 |
2014年 | 130篇 |
2013年 | 170篇 |
2012年 | 164篇 |
2011年 | 189篇 |
2010年 | 159篇 |
2009年 | 145篇 |
2008年 | 122篇 |
2007年 | 125篇 |
2006年 | 122篇 |
2005年 | 89篇 |
2004年 | 86篇 |
2003年 | 63篇 |
2002年 | 72篇 |
2001年 | 75篇 |
2000年 | 50篇 |
1999年 | 41篇 |
1998年 | 45篇 |
1997年 | 45篇 |
1996年 | 30篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 19篇 |
1992年 | 20篇 |
1991年 | 30篇 |
1990年 | 23篇 |
1989年 | 18篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1956年 | 4篇 |
1955年 | 2篇 |
排序方式: 共有3326条查询结果,搜索用时 12 毫秒
21.
Won-Il Jeong Sun Hee Do Da-Hee Jeong Jae-Yong Chung Hai-Jie Yang Dong-Wei Yuan Il-Hwa Hong Jin-Kyu Park Moon-Jung Goo Kyu-Shik Jeong 《Journal of veterinary science (Suw?n-si, Korea)》2006,7(3):299-301
Three dead dogs were brought to the College of Veterinary Medicine, Kyungpook National University for study. Clinically, all the dogs showed emaciation, anorexia, depression, hemorrhagic vomiting and diarrhea for 7~10 days before death. All the clinical signs were first noted for about one month after feeding the dogs with commercial diets. At necropsy, all 3 dogs had severe renal damage with the same green-yellowish colored nephroliths in the renal pelvis. They also showed systemic hemorrhage and calcification of several organs, which might have been induced by uremia. Microscopically, necrosis, calcification and calculi were detected in the renal tubules, and especially in the proximal convoluted tubules and collecting ducts of the kidney. These findings were supportive of a mycotoxic effect, and especially on their kidneys. However, the precise cause of the toxic effect in these cases of canine renal failure could not be determined. 相似文献
22.
The effect of fertility control on the transmission of bovine tuberculosis in wild brushtail possums
AIM: To determine the effect of fertility control on the rate of transmission of bovine tuberculosis (Tb), caused by Mycobacterium bovis, in brushtail possums (Trichosurus vulpecula). METHODS: At two study sites with a history of Tb infection in the resident possum population, a sample of adult male and female possums (n=50), determined by palpation to be Tb-free, was surgically sterilised by gonadectomy. A sample of untreated Tb-free male and female possums (n=54) served as controls. Each study site was trapped every 2 months over a 3-year period, and the Tb status of the individuals in the trial assessed. At the conclusion of the trial, all remaining experimental individuals were killed, necropsied and examined for characteristic lesions typical of Tb. The rate of transmission of Tb infection was estimated using the incidence of tuberculous cases in the experimental animals and comparing it between sites, sex and sterilisation treatment. RESULTS: Sterilisation by gonadectomy resulted in a reduction in the rate of transmission of Tb in male possums by 53%, but a corresponding increase in sterilised females for reasons that are still unclear. However, this interaction was statistically weak (p=0.10). When the sexes were combined, there was no overall effect of sterilisation on the rate of transmission of Tb (p=0.43). Sterility treatment notwithstanding, there was a highly significant difference in the rate of transmission between the sexes (p=0.01), being almost one order of magnitude higher in untreated males compared with untreated females. CONCLUSIONS: Although lacking strong statistical support, these results suggest that fertility control that targets endocrine control of fertility may provide some additional benefits for disease control over that achieved by reductions in population density, by reducing the rate of transmission of M. bovis in male possums. However, additional studies are needed to confirm the validity of these results. The large difference in the rate of transmission of M. bovis in untreated males compared with untreated females suggests that transmission of Tb among males may be an important driver of the dynamics of Tb infection in possums. 相似文献
23.
Catherine L. Rogers DVM DACVECC ; Christopher Gibson VMD ; Susan L. Mitchell DVM DACVS ; John H. Keating DVM DACVP Elizabeth A. Rozanski DVM DACVIM DACVECC 《Journal of Veterinary Emergency and Critical Care》2009,19(2):193-198
Objective – To describe a severe case of bacterial sepsis and disseminated candidiasis in a previously healthy dog.
Case Summary – Fungal sepsis was identified in a 2-year-old dog following intestinal dehiscence 4 days after abdominal surgery. Septic peritonitis was identified at admission and evidence of dehiscence at the previous enterotomy site was found during an exploratory laparotomy. Both gram-positive cocci and Candida albicans were cultured from the abdominal cavity. Candida sp. was also subsequently cultured from a central venous catheter. Euthanasia was performed due to failure to respond to therapy. Fungal organisms, morphologically consistent with Candida spp., were found in the lungs and kidney on postmortem histopathologic examination indicating disseminated candidiasis.
New or Unique Information Provided – Candida peritonitis is a well-recognized entity in humans and contributes to morbidity and mortality in critically ill patients. Abdominal surgery, intestinal perforation, presence of central venous catheters, and administration of broad-spectrum antibiotics are all considered to be suspected risk factors. This report describes the first known case of systemic candidiasis occurring secondary to Candida peritonitis and bacterial sepsis in a critically ill dog. 相似文献
Case Summary – Fungal sepsis was identified in a 2-year-old dog following intestinal dehiscence 4 days after abdominal surgery. Septic peritonitis was identified at admission and evidence of dehiscence at the previous enterotomy site was found during an exploratory laparotomy. Both gram-positive cocci and Candida albicans were cultured from the abdominal cavity. Candida sp. was also subsequently cultured from a central venous catheter. Euthanasia was performed due to failure to respond to therapy. Fungal organisms, morphologically consistent with Candida spp., were found in the lungs and kidney on postmortem histopathologic examination indicating disseminated candidiasis.
New or Unique Information Provided – Candida peritonitis is a well-recognized entity in humans and contributes to morbidity and mortality in critically ill patients. Abdominal surgery, intestinal perforation, presence of central venous catheters, and administration of broad-spectrum antibiotics are all considered to be suspected risk factors. This report describes the first known case of systemic candidiasis occurring secondary to Candida peritonitis and bacterial sepsis in a critically ill dog. 相似文献
24.
25.
2006-2007年期间,山东6地区规模化毛皮动物养殖场出现母狐空怀、流产,幼狐呼吸困难,鼻孔出血,气喘并伴有腹泻、死亡等症状,为探明病因,对发病场进行流行病学调查和送检的236份病料组织进行病原学检查,结果表明造成该病的主要原因是由绿脓杆菌(Pseudomonas aerudinosa)、沙门菌(Salmonella)、大肠杆菌(Escherichia coli)和普通变形杆菌(Proteus vulgaris)共感染所致.这4种细菌单独感染、二重感染、三重感染和四重感染的平均感染率分别为50%、45.8%、3.8%和0.4 0%.在分离的4种细菌中以绿脓杆菌的分离率为最高,达到86%,对该痛原又进行(G+C)mol%、16SrRNA序列同源性和系统发育分析,构建了包括9株邻近种属细菌在内的系统发育树,其中与绿脓杆菌(AJ249451)同源性最高,为99.2%,进一步确定该病原菌属于假单胞菌属中绿脓杆菌.本研究为目前规模化毛皮动物养殖场蓝狐病的原因提出了新的思路,为疾病的防治提供了依据. 相似文献
26.
The protozoan parasite Neospora caninum is a major cause of abortion in cattle throughout the world. In the process of propagating Neospora in vitro and producing specific antibodies for development of diagnostic assays in the food supply, our laboratory identified the presence of bovine antibodies to N. caninum in fetal bovine sera. The sera were produced commercially and preferentially recommended for tissue culture use and monoclonal antibody production. Seventeen different fetal bovine serum samples of different grades and from four different companies were examined for the presence of total IgG, IgG1, IgG2, and IgM specific for N. caninum. All of the tested serum samples recognized N. caninum specific bands on Western blot. Low IgG serum also recognized these antigens but with lower intensity. Antibody response was also evaluated using a commercially available ELISA kit for N. caninum. 相似文献
27.
28.
布鲁氏菌(Brucella)是一种兼性胞内寄生致病菌,虽无典型的毒力因子却有很强的致病力,且常导致慢性持续感染。布鲁氏菌病被列入世界上严重的人兽共患病之一,直接对畜牧业造成重大经济损失,严重威胁人类健康和公共卫生安全。布鲁氏菌感染的靶细胞主要是巨噬细胞,其发展了更高的策略逃逸宿主免疫细胞的杀伤,甚至在细胞内大量繁殖,削弱巨噬细胞的功能,使巨噬细胞的杀伤作用和抗原递呈功能部分丧失,从而能在宿主细胞内长期持续性感染。文章围绕布鲁氏菌胞内存活机制进行探讨,分析了不同极化类型的巨噬细胞在布鲁氏菌感染过程中的调控作用,以及相关炎症通路对机体炎症发展的作用;揭示了布鲁氏菌胞内生存不仅可适应持续感染期间不同的免疫微环境,也可适应感染期间靶细胞营养物质利用率的差异;证实了在慢性感染的过程中免疫逃避和与宿主细胞代谢的相互作用起关键作用;解释了NF-κB通路是调节M1/M2型巨噬细胞亚型平衡状态的关键因素。布鲁氏菌在宿主细胞中持续感染是国内外学者所面临的巨大难题,其免疫逃逸机制和致病机制仍需进一步研究。 相似文献
29.