全文获取类型
| 收费全文 | 192985篇 |
| 免费 | 10759篇 |
| 国内免费 | 112篇 |
专业分类
| 林业 | 7751篇 |
| 农学 | 5940篇 |
| 基础科学 | 1319篇 |
| 22820篇 | |
| 综合类 | 33946篇 |
| 农作物 | 7200篇 |
| 水产渔业 | 9489篇 |
| 畜牧兽医 | 99467篇 |
| 园艺 | 2383篇 |
| 植物保护 | 13541篇 |
出版年
| 2018年 | 2385篇 |
| 2017年 | 2656篇 |
| 2016年 | 2507篇 |
| 2015年 | 2184篇 |
| 2014年 | 2666篇 |
| 2013年 | 7219篇 |
| 2012年 | 4990篇 |
| 2011年 | 6169篇 |
| 2010年 | 3962篇 |
| 2009年 | 3997篇 |
| 2008年 | 6133篇 |
| 2007年 | 5821篇 |
| 2006年 | 5603篇 |
| 2005年 | 5282篇 |
| 2004年 | 5083篇 |
| 2003年 | 5168篇 |
| 2002年 | 4910篇 |
| 2001年 | 5938篇 |
| 2000年 | 5768篇 |
| 1999年 | 4672篇 |
| 1998年 | 1925篇 |
| 1997年 | 1968篇 |
| 1995年 | 2284篇 |
| 1994年 | 2031篇 |
| 1993年 | 1946篇 |
| 1992年 | 3982篇 |
| 1991年 | 4213篇 |
| 1990年 | 4308篇 |
| 1989年 | 4243篇 |
| 1988年 | 3952篇 |
| 1987年 | 4035篇 |
| 1986年 | 4106篇 |
| 1985年 | 3968篇 |
| 1984年 | 3419篇 |
| 1983年 | 3006篇 |
| 1982年 | 2077篇 |
| 1981年 | 1892篇 |
| 1980年 | 1844篇 |
| 1979年 | 3074篇 |
| 1978年 | 2498篇 |
| 1977年 | 2216篇 |
| 1976年 | 2017篇 |
| 1975年 | 2143篇 |
| 1974年 | 2789篇 |
| 1973年 | 2839篇 |
| 1972年 | 2726篇 |
| 1971年 | 2485篇 |
| 1970年 | 2346篇 |
| 1969年 | 2218篇 |
| 1967年 | 1981篇 |
排序方式： 共有10000条查询结果，搜索用时 406 毫秒
81.
Hybridomas were produced from fusions of the SP2/0 mouse myeloma with splenic cells from: 1) an outbred Sprague Dawley rat immunized with swine peripheral blood mononuclear (PBM) cells; 2) a (CBA/NDub X BALB/c Dub) F1 mouse immunized with concanavalin A (Con A) activated swine PBM cells and 3) a (BALB/c Dub X C3H/He Dub) F1 mouse immunized with swine thymocytes. The resulting supernatants were screened by a microcytotoxicity assay for activity against swine PBM cells. Four hybridomas (MSA1, MSA2, MSA3 and MSA4) were selected, cloned and characterized by their cell reactivity and effect on mitogenic assays. MSA1 and MSA2 belong to the rat IgG2b subclass. MSA3 and MSA4 are of the mouse IgG2a subclass. These monoclonal antibodies reacted in the following manner: MSA1 with monocytes, granulocytes, red blood cells and bone marrow cells; MSA2 with subset of T cells; MSA3 with B cells and subsets of T cells and monocytes (class II molecule) and MSA4, a pan-T cell reagent (E-rosette receptor). The involvement of the various cell types reactive to the different monoclonal antibodies in the mitogenic response of swine PBM cells to Con A, phytohemagglutinin (PHA) or pokeweed mitogen (PWM) was investigated by cellular depletion with monoclonal antibody plus complement. Cellular depletion of PBM cells with the following monoclonal antibodies plus complement treatment resulted in: MSA1, almost total reduction in the mitogenic response to low doses of Con A or PWM; MSA2, partial reduction in the proliferative responses to any concentration of Con A, PHA or PWM; MSA3, partial reduction in proliferative responses to low concentrations of Con A or PWM and 4) MSA4, total elimination of any proliferative response to Con A, PHA or PWM. 相似文献
82.
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
83.
84.
Wodsedalek JE 《Science (New York, N.Y.)》1917,46(1189):366-367
85.
86.
87.
88.
89.
90.