全文获取类型
收费全文 | 87385篇 |
免费 | 5190篇 |
国内免费 | 43篇 |
专业分类
林业 | 2984篇 |
农学 | 2719篇 |
基础科学 | 526篇 |
9945篇 | |
综合类 | 16200篇 |
农作物 | 3665篇 |
水产渔业 | 4308篇 |
畜牧兽医 | 45562篇 |
园艺 | 1082篇 |
植物保护 | 5627篇 |
出版年
2019年 | 808篇 |
2018年 | 1195篇 |
2017年 | 1377篇 |
2016年 | 1291篇 |
2015年 | 1145篇 |
2014年 | 1364篇 |
2013年 | 3455篇 |
2012年 | 2567篇 |
2011年 | 3055篇 |
2010年 | 1982篇 |
2009年 | 1949篇 |
2008年 | 2940篇 |
2007年 | 2843篇 |
2006年 | 2690篇 |
2005年 | 2538篇 |
2004年 | 2390篇 |
2003年 | 2419篇 |
2002年 | 2276篇 |
2001年 | 2906篇 |
2000年 | 2783篇 |
1999年 | 2269篇 |
1998年 | 975篇 |
1997年 | 894篇 |
1996年 | 790篇 |
1995年 | 958篇 |
1994年 | 863篇 |
1993年 | 857篇 |
1992年 | 1813篇 |
1991年 | 1812篇 |
1990年 | 1751篇 |
1989年 | 1817篇 |
1988年 | 1570篇 |
1987年 | 1681篇 |
1986年 | 1740篇 |
1985年 | 1667篇 |
1984年 | 1312篇 |
1983年 | 1167篇 |
1982年 | 843篇 |
1981年 | 723篇 |
1979年 | 1108篇 |
1978年 | 901篇 |
1977年 | 782篇 |
1976年 | 735篇 |
1975年 | 810篇 |
1974年 | 999篇 |
1973年 | 1041篇 |
1972年 | 994篇 |
1971年 | 946篇 |
1970年 | 887篇 |
1969年 | 811篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Extract Scouring syndromes constitute a major disease group in dairy calves in New Zealand. 相似文献
993.
A.A. Twaddle B.V.Sc. M.R.C.V.S. 《New Zealand veterinary journal》2013,61(1-2):26-27
Abstract Extract Rural veterinary practice faces difficulties in many parts of the world. Falling farm incomes and increasing costs have sometimes resulted in reduced use of veterinary services. There seems to be widespread agreement that an increased emphasis on preventive medicine would improve the situation for both the farmer and his veterinarian. There appear to be no commonly agreed formal criteria for the development and evaluation of health programmes, either in human or veterinary medicine, but increasing attention is being paid to the problem(1) (12) (14) (15), In some ways the evaluation of animal health programmes should be the easier, for there are fewer ethical problems and economic criteria are of paramount importance in rural practice. 相似文献
994.
T.M. Skerman M.Sc. Ph.D. I.M. Cairney B.V.Sc. M.R.C.V.S. 《New Zealand veterinary journal》2013,61(11):205-211
Extract I have taken as my subject for this address the topic, “Change”, and will deal with two aspects of change, one the challenge of change due to new knowledge and techniques and second the change we must make in our attitude to other agricultural disciplines and ancillary veterinary personnel. 相似文献
995.
The design and development of an efficient sod‐seeder for the Ngongoni Veld of Natal is described. 相似文献
996.
997.
Oesophageal rupture in horses has only been previously described in detail in isolated case reports. The objectives of this study were to describe the clinical findings, specific treatment and outcome of oesophageal rupture in horses. Medical records of horses diagnosed with oesophageal rupture between 1994–2008 were reviewed. Clinical findings, treatment and outcome were recorded. Seven horses with cervical oesophageal perforations were included in the study. Two horses were subjected to euthanasia without treatment and 5 were treated surgically. Treatment involved a fasciotomy of the cervical musculature and oesophageal tube placement. Three of 5 horses survived long‐term (>one year). Our study showed that surgical treatment of cervical oesophageal rupture involving fasciotomy and oesophagostomy tube placement can be successful with 3/5 of treated horses surviving more than one year. 相似文献
998.
L. NAGORE C. SOLER L. GIL I. SERRA G. SOLER J. I. REDONDO 《Journal of veterinary pharmacology and therapeutics》2013,36(3):222-228
The purpose of this study was to assess the clinical effects of dexmedetomidine, both alone and combined with pethidine or butorphanol, in cats. A prospective randomized blind study was performed. Thirty cats were randomly assigned to three groups of 10 animals: D: dexmedetomidine (20 μg/kg IM); DP: dexmedetomidine (10 μg/kg IM) and pethidine (2.5 mg/kg IM); DB: dexmedetomidine (10 μg/kg IM) and butorphanol (0.4 mg/kg IM). Quality of sedation, analgesia, muscle relaxation and the possibility of performing some clinical procedures were compared using a multifactorial scale. Sedation, analgesia and muscle relaxation increased progressively over time and did not differ in the three protocols. The three protocols facilitated the completion of several clinical procedures. The clinical variables studied showed a similar behaviour in the three protocols and remained close to the baseline, except for a drop in heart rate in protocol D. In conclusion, dexmedetomidine, either alone or combined with pethidine or butorphanol, offers suitable sedation, analgesia and relaxation to perform various clinical procedures in cats. 相似文献
999.
Hywel C. Williams 《Veterinary dermatology》2013,24(1):3-e2
Background – This narrative review highlights areas within the epidemiology of human atopic dermatitis (AD) where significant progress has been made and where considerable ignorance still exists. The review is supported by systematic reviews wherever possible, with the purpose of stimulating fresh approaches to human and veterinary research into AD. Progress – Areas of progress include valid and repeatable methods of disease definition, global documentation of disease prevalence and impact, clarification of the role of some genetic factors, such as filaggrin gene mutations, clear evidence that environmental factors are key, as demonstrated by the positive social class gradient and rising prevalence, a possible protective effect of infections in early life, documentation of comorbidities, such as a reduced risk of glioma, and mapping the evidence base through systematic reviews and an online global resource of clinical trials. Ignorance – Areas where significant uncertainty still exists include the question of whether AD is more than one disease, the tendency for researchers to look at the same old risk factors, lack of specific environmental risk factors that are amenable to manipulation, inconsistencies in the hygiene hypothesis, sparse knowledge about adult AD, lack of evidence that eczema can be prevented, and little scientific work exploring what causes flares in people with established AD. 相似文献
1000.