全文获取类型
收费全文 | 167756篇 |
免费 | 9230篇 |
国内免费 | 88篇 |
专业分类
林业 | 6594篇 |
农学 | 5131篇 |
基础科学 | 1077篇 |
19165篇 | |
综合类 | 33111篇 |
农作物 | 6898篇 |
水产渔业 | 7891篇 |
畜牧兽医 | 84801篇 |
园艺 | 2074篇 |
植物保护 | 10332篇 |
出版年
2018年 | 2048篇 |
2017年 | 2299篇 |
2016年 | 2194篇 |
2015年 | 1921篇 |
2014年 | 2254篇 |
2013年 | 6303篇 |
2012年 | 4407篇 |
2011年 | 5350篇 |
2010年 | 3543篇 |
2009年 | 3487篇 |
2008年 | 5241篇 |
2007年 | 4986篇 |
2006年 | 4767篇 |
2005年 | 4483篇 |
2004年 | 4433篇 |
2003年 | 4416篇 |
2002年 | 4236篇 |
2001年 | 5259篇 |
2000年 | 5163篇 |
1999年 | 4005篇 |
1998年 | 1751篇 |
1997年 | 1752篇 |
1996年 | 1569篇 |
1995年 | 1933篇 |
1994年 | 1791篇 |
1993年 | 1720篇 |
1992年 | 3556篇 |
1991年 | 3712篇 |
1990年 | 3616篇 |
1989年 | 3729篇 |
1988年 | 3324篇 |
1987年 | 3467篇 |
1986年 | 3646篇 |
1985年 | 3509篇 |
1984年 | 2816篇 |
1983年 | 2586篇 |
1982年 | 1808篇 |
1981年 | 1656篇 |
1979年 | 2548篇 |
1978年 | 2057篇 |
1977年 | 1701篇 |
1976年 | 1641篇 |
1975年 | 1758篇 |
1974年 | 2216篇 |
1973年 | 2302篇 |
1972年 | 2238篇 |
1971年 | 2150篇 |
1970年 | 1996篇 |
1969年 | 1838篇 |
1967年 | 1572篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
961.
962.
963.
Norman C 《Science (New York, N.Y.)》1986,233(4767):934-935
964.
965.
966.
C E Harvey 《Veterinary Clinics of North America: Small Animal Practice》1986,16(5):983-993
The results obtained following both maxillectomy and mandibulectomy in animals with benign disease show that these procedures are practical. The challenge is to select those animals with malignant disease where the disease is sufficiently localized so that radical resection will be curative, or where residual disease can be controlled by adjuvant therapy. The series of cases reported in Tables 1 and 2 represent animals treated during the "developmental phase" of these procedures. With 5 years of case experience now available, the usefulness and limitations of these procedures are becoming clearer. 相似文献
967.
968.
Effect of Pasteurella multocida and Haemophilus pleuropneumoniae toxins on swine alveolar macrophages 总被引:3,自引:0,他引:3
C Pijoan 《Veterinary immunology and immunopathology》1986,13(1-2):141-149
Supernatants were obtained from 18 hr. broth cultures of Pasteurella multocida strains D82 and D62 (serotype D, toxigenic), Kobe 6 (type D, non-toxigenic), A50 and X73 (type A, non-toxigenic), Haemophilus pleuropneumoniae serotypes 1, 5 and 6, Haemophilus sp. taxon "minor group" (2 strains) and an avirulent serotype 1 strain of H. pleuropneumoniae. The supernates were filtered, pH-neutralized and tested for cytotoxicity after incubation for 18 hours in the presence of swine alveolar macrophage monolayers. Supernatants from H. pleuropneumoniae serotypes 1, 5 and 6 were cytocidal. 相似文献
969.
A ram lamb with congenital goitre showed signs of respiratory distress at birth. All previously affected lambs from this flock bad been born dead or bad died soon after birth. The serum free-thyroxine level at 1 birth was low (9.8 pmol/l) but treatment with oral L-thyroxine resulted in an increase in thyroxine blood levels to above normal and regression of the goitre. Four weeks after withdrawal of thyroid supplementation and when the lamb was eight weeks old, the radio iodide uptake mechanism of the thyroid glands was shown to be intact but the iodide was not organified. Low normal peroxidase activity was demonstrated in fresh thyroid tissue but gel electrophoresis demonstrated an absence of normal thyroglobulin from extracts of the goitrous thyroid. This lamb and the other affected lambs of this flock have an inherited defect in thyroglobulin synthesis and it is likely that the respiratory distress was associated with the low levels of thyroid hormone affecting foetal lung development. 相似文献
970.
On a property in the Nelson District, blood and urine samples were taken from red deer (Cervus elaphus) from which low (<1:100) antibody titres to serovar copenhageni and suspected leptospiral abortions had previously been reported. A total of 27 hinds were sampled. Microscopic agglutination test (MAT) titres in sera ranging from 1:32 to 1:128 were found in six animals. Thirteen leptospiral isolations were made from nine of the 27 urine samples. Four of these were typed as copenhageni and nine as hardjo. Two cultures were prepared from each urine sample and hardjo and copenhageni were both isolated from single urine samples from two animals. None of the 27 deer had serum MAT titres at 1:32 or above to copenhageni. 相似文献