全文获取类型
| 收费全文 | 162908篇 |
| 免费 | 7559篇 |
| 国内免费 | 82篇 |
专业分类
| 林业 | 10266篇 |
| 农学 | 5645篇 |
| 基础科学 | 1055篇 |
| 20234篇 | |
| 综合类 | 29947篇 |
| 农作物 | 7937篇 |
| 水产渔业 | 8385篇 |
| 畜牧兽医 | 73811篇 |
| 园艺 | 2676篇 |
| 植物保护 | 10593篇 |
出版年
| 2018年 | 4620篇 |
| 2017年 | 4781篇 |
| 2016年 | 3065篇 |
| 2015年 | 1689篇 |
| 2014年 | 1944篇 |
| 2013年 | 5382篇 |
| 2012年 | 4569篇 |
| 2011年 | 6808篇 |
| 2010年 | 5323篇 |
| 2009年 | 4577篇 |
| 2008年 | 5980篇 |
| 2007年 | 6144篇 |
| 2006年 | 4011篇 |
| 2005年 | 3872篇 |
| 2004年 | 3894篇 |
| 2003年 | 3925篇 |
| 2002年 | 3690篇 |
| 2001年 | 4365篇 |
| 2000年 | 4376篇 |
| 1999年 | 3328篇 |
| 1998年 | 1412篇 |
| 1997年 | 1437篇 |
| 1995年 | 1619篇 |
| 1994年 | 1507篇 |
| 1993年 | 1487篇 |
| 1992年 | 3020篇 |
| 1991年 | 3164篇 |
| 1990年 | 3068篇 |
| 1989年 | 3144篇 |
| 1988年 | 2874篇 |
| 1987年 | 2987篇 |
| 1986年 | 3100篇 |
| 1985年 | 3030篇 |
| 1984年 | 2443篇 |
| 1983年 | 2247篇 |
| 1982年 | 1486篇 |
| 1981年 | 1406篇 |
| 1979年 | 2225篇 |
| 1978年 | 1825篇 |
| 1977年 | 1528篇 |
| 1976年 | 1478篇 |
| 1975年 | 1557篇 |
| 1974年 | 2030篇 |
| 1973年 | 2046篇 |
| 1972年 | 2054篇 |
| 1971年 | 1999篇 |
| 1970年 | 1826篇 |
| 1969年 | 1723篇 |
| 1968年 | 1374篇 |
| 1967年 | 1498篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
71.
Thirteen mixed-breed beef bulls, 1 to 4 years old, were used to determine the effect of live and dead filarial nematodes, Setaria labiatopapillosa, placed in the vaginal cavity of the testes. When dead worms were used, granulomatous lesions developed on the tunica vaginalis parietalis in 7 of 8 testes. The lesions were similar to those seen in some clinical cases of periorchitis. Similar lesions developed in 5 of 6 testes after live worms were implanted in the vaginal cavity of the testes and tetramisole (8 mg/kg) was injected subcutaneously 6 days after implantation. When live worms were implanted and tetramisole was not given, lesions developed in 3 of 6 testes. It was concluded that the granulomatous reaction was a local response to dead or killed S labiatopapillosa. 相似文献
72.
Mid-storage hydration-dehydration treatments with medium-vigour lettuce seed very effectively reduced physiological deterioration in storage and ultimately showed better field emergence and final yield. Soaking-drying treatment of high-vigour lettuce seed was not effective. Pre-sowing treatment of medium-vigour lettuce seed, though less effective than mid-storage treatment, gave better field performance, but high-vigour seed did not benefit from the treatment. For carrot, both mid-storage and pre-sowing seed treatments proved beneficial, with the former showing better performance than the latter. Unlike lettuce, well-preserved carrot seed responded positively to the pre-sowing treatment. 相似文献
73.
Washed and unwashed red blood cells (RBC) from young calves, adult cattle, hamsters and humans were incubated with Leptospira interrogans serovars pomona and ballum. Washed cells suspended in saline were always haemolysed while unwashed cells and those which were washed and resuspended in plasma were never haemolysed, despite the presence of large numbers of organisms within the culture supernatant. Pomona produced greater haemolysis of cattle and human RBC than did ballum, but with hamster RBC ballum produced greater haemolysis than did pomona. A group of 6- to 9-month-old cattle infected with pomona showed no signs of clinical disease and RBC taken from them before infection and during the development of antibodies to pomona were haemolysed by pomona only after the cells were washed. Plasma therefore appears to have a protective function. This in vitro protective function of plasma even extended to plasma from young seronegative calves. 相似文献
74.
75.
Dorfman RI 《Science (New York, N.Y.)》1940,92(2399):585-586
In addition to the well-defined phenolic estrogens in human pregnancy urine there appears to be another estrogenic substance which is a neutral non-ketonic compound. 相似文献
76.
77.
78.
R. 《European Journal of Forest Research》1865,9(1):384-387
Ohne Zusammenfassung 相似文献
79.
80.
Isaacs R 《Science (New York, N.Y.)》1928,68(1770):547-548