全文获取类型
| 收费全文 | 149268篇 |
| 免费 | 8459篇 |
| 国内免费 | 87篇 |
专业分类
| 林业 | 5735篇 |
| 农学 | 4498篇 |
| 基础科学 | 1054篇 |
| 17713篇 | |
| 综合类 | 25963篇 |
| 农作物 | 5561篇 |
| 水产渔业 | 7550篇 |
| 畜牧兽医 | 77214篇 |
| 园艺 | 1902篇 |
| 植物保护 | 10624篇 |
出版年
| 2018年 | 1900篇 |
| 2017年 | 2070篇 |
| 2016年 | 1961篇 |
| 2015年 | 1711篇 |
| 2014年 | 2089篇 |
| 2013年 | 5604篇 |
| 2012年 | 4028篇 |
| 2011年 | 5049篇 |
| 2010年 | 3106篇 |
| 2009年 | 3111篇 |
| 2008年 | 4913篇 |
| 2007年 | 4702篇 |
| 2006年 | 4570篇 |
| 2005年 | 4248篇 |
| 2004年 | 4126篇 |
| 2003年 | 4134篇 |
| 2002年 | 4054篇 |
| 2001年 | 4721篇 |
| 2000年 | 4578篇 |
| 1999年 | 3751篇 |
| 1998年 | 1502篇 |
| 1997年 | 1526篇 |
| 1996年 | 1431篇 |
| 1995年 | 1770篇 |
| 1994年 | 1609篇 |
| 1993年 | 1542篇 |
| 1992年 | 3176篇 |
| 1991年 | 3312篇 |
| 1990年 | 3349篇 |
| 1989年 | 3349篇 |
| 1988年 | 3071篇 |
| 1987年 | 3150篇 |
| 1986年 | 3253篇 |
| 1985年 | 3107篇 |
| 1984年 | 2636篇 |
| 1983年 | 2327篇 |
| 1982年 | 1599篇 |
| 1981年 | 1488篇 |
| 1980年 | 1441篇 |
| 1979年 | 2331篇 |
| 1978年 | 1927篇 |
| 1977年 | 1642篇 |
| 1976年 | 1450篇 |
| 1975年 | 1550篇 |
| 1974年 | 2083篇 |
| 1973年 | 2101篇 |
| 1972年 | 2061篇 |
| 1971年 | 1823篇 |
| 1970年 | 1718篇 |
| 1969年 | 1578篇 |
排序方式： 共有10000条查询结果，搜索用时 281 毫秒
81.
82.
83.
84.
85.
86.
Isolated dog neutrophils exposed to known chemotactic factors assumed a bipolar configuration in suspension. This response was initiated within 2 minutes with a gradual return to spherical shape. The rate of return to sphere was positively correlated with the dose of stimulant. Dog neutrophils exposed to N-formylmethionyl-leucyl-phenylalanine (fMLP) did not adapt to bipolar conformation and did not bind radiolabeled fMLP. These findings are consistent with other species (pig and cow) that also did not respond to fMLP. 相似文献
87.
C A Osborne T D O'Brien H K Ghobrial L Meihak J B Stevens 《Veterinary Clinics of North America: Small Animal Practice》1986,16(1):45-65
Crystalluria results from oversaturation of urine with crystallogenic substance. However, oversaturation may occur as a result of in vitro as well as in vivo events. The microscopic appearance of crystals only represents a tentative identification of their composition because variable conditions associated with their formation, growth, and dissolution may alter their appearance. Definitive identification is dependent on physical methods such as optical crystallography, x-ray diffraction, and electron microscopic analysis. 相似文献
88.
Disseminated Aspergillus terreus infection was diagnosed in ten previously healthy adult dogs--nine German shepherds and one dalmatian. The disease was characterized by the presence of multiple granulomas and infarcts in a wide range of organs. The kidney, spleen, and skeletal system were most commonly and severely affected. Fungal hyphae were demonstrated in large numbers within granulomas and thrombi, and A. terreus was readily isolated by culture. This disseminated mycosis appears unique; in this series of cases there was no apparent predisposing factor, portal of entry, or primary focus for dissemination of the infection. 相似文献
89.
B J Culliton 《Science (New York, N.Y.)》1989,245(4919):697-698
90.
A steam-dryer, designed and manufactured in Sweden, was evaluated for destroying Bursaphelenchus xylophilus in pine chips from southern USA. In a trial, pine chips were treated at different temperature and pressure regimes for 5 or 10min. The lowest time/temperature/pressure combination was to increase the vessel temperature from 85 to 104°C in 5 min at low pressure. Samples of pine chips were assayed for nematodes in laboratories in USA, Sweden, and Finland. No nematodes of any species were recovered from any of the treated pine-chip samples. Large and heterogeneous pieces of wood in the treated samples were also nematode-free. The apparatus was a prototype capable of handling about 400 kg h-1 . The final version would have to be able to process 100-200 th-1 . 相似文献