全文获取类型
收费全文 | 132355篇 |
免费 | 7398篇 |
国内免费 | 92篇 |
专业分类
林业 | 5382篇 |
农学 | 4269篇 |
基础科学 | 831篇 |
17036篇 | |
综合类 | 21484篇 |
农作物 | 5401篇 |
水产渔业 | 6698篇 |
畜牧兽医 | 67962篇 |
园艺 | 1800篇 |
植物保护 | 8982篇 |
出版年
2020年 | 1177篇 |
2019年 | 1376篇 |
2018年 | 2031篇 |
2017年 | 2331篇 |
2016年 | 2096篇 |
2015年 | 1744篇 |
2014年 | 2225篇 |
2013年 | 5292篇 |
2012年 | 4114篇 |
2011年 | 5096篇 |
2010年 | 3246篇 |
2009年 | 3390篇 |
2008年 | 4972篇 |
2007年 | 4667篇 |
2006年 | 4353篇 |
2005年 | 4089篇 |
2004年 | 3851篇 |
2003年 | 3973篇 |
2002年 | 3542篇 |
2001年 | 4150篇 |
2000年 | 4252篇 |
1999年 | 3372篇 |
1998年 | 1474篇 |
1997年 | 1387篇 |
1996年 | 1288篇 |
1995年 | 1529篇 |
1994年 | 1358篇 |
1993年 | 1231篇 |
1992年 | 2584篇 |
1991年 | 2700篇 |
1990年 | 2591篇 |
1989年 | 2611篇 |
1988年 | 2368篇 |
1987年 | 2348篇 |
1986年 | 2427篇 |
1985年 | 2340篇 |
1984年 | 1881篇 |
1983年 | 1677篇 |
1982年 | 1149篇 |
1979年 | 1748篇 |
1978年 | 1397篇 |
1977年 | 1151篇 |
1976年 | 1212篇 |
1975年 | 1292篇 |
1974年 | 1500篇 |
1973年 | 1514篇 |
1972年 | 1405篇 |
1971年 | 1304篇 |
1970年 | 1251篇 |
1969年 | 1283篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
943.
944.
945.
946.
947.
948.
van der Schaaf A 《The Veterinary quarterly》1979,1(4):212-228
Summary As a prisoner of war the writer was working for nearly three years in different POW camps, and outside them, along the Burma railway from Thanbyuyzat in southern Burma up to Kanchanabury in Thailand. In the army of the Netherlands-Indian archipelago (KNIL) he had the military rank of reserve horse-doctor. In civilian life he was attached to the Veterinary Institute in Buitenzorg (now Bogor) as a veterinary bacteriologist. His task as a POW became that of meathygienist and supervisor of the living animals in the camps. In this function he diagnosed swine fever in growing pigs which had mainly been fed on the offal of the Japanese kitchen. The acute course and the pathological alterations observed during the post-mortem examinations were identical with those of the Southern-African type of the disease. In slaughter cattle the author diagnosed some cases of lung tuberculosis, one of anthrax, several of rinderpest, some of rhinal granulomatosis and one of foot and mouth disease. In chickens he found NCD (pseudo-fowlpest) and in ducklings a mortal disease which the author then called 'keeling disease' but which he many years later, recognized as virus hepatitis. As assistant bacteriologist and ex-POW he joined the British regimental hospital in Bangkok. Here he had the opportunity to assist the bacteriologist pathologist, Maj. C. R. Peck IMS / IAMC in diagnosing the first case of melioidosis in an ex-POW of the KNIL who died from the sub-acute infection, notwithstanding treatment in the hospital with sulfa-drugs and penicillin. 相似文献
949.
Summary The prevalence of antibodies to various viruses was investigated in a series of serum samples collected from horses in the Netherlands between 1963 and 1966 and from 1972 onwards. Neutralizing antibodies to equine rhinopneumonitis virus, equine arteritis virus and to equine rhinovirus types 1 and 2 were detected in respectively 76%, 14%, 66% and 59% of the equine serum samples tested. The observed incidence of serum samples positive to equine adenovirus in the complement fixation test was 39%. Precipitating antibodies to equine infectious anaemia virus were detected only in serum samples from two horses imported from abroad. Haemagglutination inhibiting antibodies to Myxovirus influenzae A / equi-1, M. Influenzae A / equi-2, and Reovirus types 1, 2, and 3 were present in respectively 82%, 50%, 10%, 33% and 3.6% of the serum samples tested. The most frequently observed incidence of antibodies to the various equine respiratory viruses occurred in the groups of horses having repeatedly contact with other horses. 相似文献
950.
F. A. Hakkaart Gusta Hartel 《European journal of plant pathology / European Foundation for Plant Pathology》1979,85(2):39-46
On the older leaves ofPelargonium zonale chlorotic rings and flecks are common, especially during spring and fall. From such plants an isometric virus can be isolated that causes local lesions on the leaves ofChenopodium quinoa. An attempt was made to produce symptomless plants, reacting negatively onC. quinoa. Meristem tips on a basal medium supplemented with α-naphthalene acetic acid and coconut milk produced abundant callus, but no plantlets. However, on media containing low concentrations of indole acetic acid and kinetin or benzyl adenine, some plants were produced that fulfilled the above requirements. Those selected on horticultural properties, are considered as valuable mother plants. Of twenty-one cultivars such plants were obtained. They may prove an important contribution to the improvement of theP. zonale industry in the Netherlands. 相似文献