全文获取类型
收费全文 | 1882篇 |
免费 | 120篇 |
国内免费 | 1篇 |
专业分类
林业 | 56篇 |
农学 | 16篇 |
基础科学 | 10篇 |
119篇 | |
综合类 | 555篇 |
农作物 | 69篇 |
水产渔业 | 160篇 |
畜牧兽医 | 933篇 |
园艺 | 21篇 |
植物保护 | 64篇 |
出版年
2021年 | 21篇 |
2020年 | 27篇 |
2019年 | 47篇 |
2018年 | 32篇 |
2017年 | 50篇 |
2016年 | 26篇 |
2015年 | 26篇 |
2014年 | 30篇 |
2013年 | 87篇 |
2012年 | 50篇 |
2011年 | 79篇 |
2010年 | 33篇 |
2009年 | 38篇 |
2008年 | 79篇 |
2007年 | 75篇 |
2006年 | 57篇 |
2005年 | 41篇 |
2004年 | 61篇 |
2003年 | 41篇 |
2002年 | 46篇 |
2001年 | 38篇 |
2000年 | 36篇 |
1999年 | 41篇 |
1998年 | 21篇 |
1997年 | 15篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1992年 | 33篇 |
1991年 | 36篇 |
1990年 | 36篇 |
1989年 | 25篇 |
1988年 | 30篇 |
1987年 | 30篇 |
1986年 | 33篇 |
1985年 | 22篇 |
1984年 | 15篇 |
1983年 | 20篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1975年 | 16篇 |
1974年 | 20篇 |
1973年 | 30篇 |
1972年 | 15篇 |
1970年 | 21篇 |
1969年 | 17篇 |
1968年 | 22篇 |
1901年 | 19篇 |
1897年 | 24篇 |
1896年 | 22篇 |
1895年 | 26篇 |
排序方式: 共有2003条查询结果,搜索用时 31 毫秒
101.
Davis WM 《Science (New York, N.Y.)》1902,15(373):313-314
102.
103.
The specificities of three monoclonal antibodies (MAbs) were investigated using microcytotoxicity, fluorescence microscopy and laser flow cytometry (LFC) techniques. By microcytotoxicity, bovine thymocytes (n = 4) were estimated to be 85% B26A+, 4% TH21A+, and 1% H4+. Nylon wool enriched peripheral blood T lymphocytes (n = 3) were 90% B26A+, 10% TH21A+ and 10% H4+. Adherent B cell enriched fractions (n = 3) were 10% B26A+, 90% TH21A+ and 90% H4+. The two fluorochrome method was used to simultaneously identify lymphocytes that were sIg+ and MAb+. In these experiments, 92% of all sIg+ cells were H4+. An identical result was obtained for TH21A. 85% of all sIg- cells were B26A+. Using LFC, the mean percentages of sIg+, H4+ and TH21A+ PBL (n = 5) were not significantly different. B26A recognized a significantly greater population of cells, equivalent to the expected percentage of T lymphocytes. LFC also revealed two relatively discrete sizes of B26A+ PBL. The larger population overlapped the size range in which sIg+, H4+, TH21A+ PBL were found. The more numerous smaller B26A+ PBL were in a size range in which few sIg+, H4+ and TH21A+ PBL were found. In a study of MAb reactions with PBL of 185 cows, it was shown that in 92% of the animals H4 and TH21A were positively correlated (r = +.93), when H4 and TH21A were negatively correlated with B26A (r = -.94 and r = -.92, respectively). These correlation coefficients indicate a converse relationship between B26A and both H4 and TH21A. The remaining 8% of the animals were heterogeneous in their expression of the H4 and TH21A markers but not the B26A marker. These results provide strong evidence that: 1) B26A is a pan-T lymphocyte MAb in cattle, 2) a small but significant degree of heterogeneity exists in the expression of the epitopes recognized by H4 and TH21A. However, both MAbs recognize all B lymphocytes of most individuals, and 3) using a variety of immunological methods these three MAbs can now reliably be used to assay bovine T and B lymphocytes. 相似文献
104.
105.
106.
107.
108.
The authors discuss the liver's influence on drug disposition in the body and the influence of drugs on the liver. Drug-induced hepatotoxicity with regard to mechanisms and causative agents is discussed, as well as administration of drugs to patients with existing liver disease. 相似文献
109.
110.