全文获取类型
收费全文 | 39341篇 |
免费 | 1985篇 |
国内免费 | 4405篇 |
专业分类
林业 | 4363篇 |
农学 | 5849篇 |
基础科学 | 3640篇 |
6475篇 | |
综合类 | 12465篇 |
农作物 | 2235篇 |
水产渔业 | 1463篇 |
畜牧兽医 | 5350篇 |
园艺 | 1402篇 |
植物保护 | 2489篇 |
出版年
2024年 | 177篇 |
2023年 | 547篇 |
2022年 | 1419篇 |
2021年 | 1837篇 |
2020年 | 1706篇 |
2019年 | 1597篇 |
2018年 | 1178篇 |
2017年 | 1627篇 |
2016年 | 1461篇 |
2015年 | 1964篇 |
2014年 | 1836篇 |
2013年 | 2206篇 |
2012年 | 2719篇 |
2011年 | 2857篇 |
2010年 | 2607篇 |
2009年 | 2393篇 |
2008年 | 2166篇 |
2007年 | 2063篇 |
2006年 | 1952篇 |
2005年 | 1764篇 |
2004年 | 814篇 |
2003年 | 708篇 |
2002年 | 571篇 |
2001年 | 598篇 |
2000年 | 676篇 |
1999年 | 837篇 |
1998年 | 774篇 |
1997年 | 661篇 |
1996年 | 594篇 |
1995年 | 638篇 |
1994年 | 505篇 |
1993年 | 436篇 |
1992年 | 458篇 |
1991年 | 341篇 |
1990年 | 301篇 |
1989年 | 203篇 |
1988年 | 164篇 |
1987年 | 126篇 |
1986年 | 63篇 |
1985年 | 34篇 |
1984年 | 31篇 |
1983年 | 17篇 |
1982年 | 26篇 |
1981年 | 20篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1977年 | 4篇 |
1966年 | 4篇 |
1964年 | 5篇 |
1956年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
季节会影响到大鲵肌肉的脂肪及钙的含量,肝脏的脂肪、钙及游离氨基酸的含量,饥饿对肌肉的酸化成分不产生影响,但饥饿程度的增加,会对肝脏脂肪无氮浸出物及游离氨基酸产生影响;繁殖前雌性大鲵的肌肉肝脏的肪肪含量均高于雄性的。 相似文献
3.
4.
M P Yang R Goitsuka H Tsujimoto M Onuma A Hasegawa 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(4):757-761
The association of tumor-associated antigen (TAA) on the proliferation of BLV-infected lymphoblastoid B-cell lines (BL2M3 and BL312) was investigated. Flow cytometric analysis of the expression of TAA with monoclonal antibody (mAb) c143 showed high expression of TAA on the surfaces of BL2M3 and BL312 cells. A large amount of TAA was found in the culture supernatant of BL2M3 and BL312 cells as well as in the lysates of BL2M3 and BL312 cells. Culture supernatant but not lysates of BL2M3 and BL312 cells promoted the growth of either BL2M3 cells or BL312 cells. Furthermore, this growth promoting activity in culture supernatants of BL2M3 and BL312 cells was inhibited in a dose-dependent manner when cultured with mAb c143. These results suggested that TAA may be involved in the growth factor-mediated cell growth of bovine B-lymphoblastoid cell lines expressing TAA on their cell surface. 相似文献
5.
6.
7.
8.
Cheng-Zhe Ren Hui-Min Gao Jun Dai Wen-Zhuo Zhu Fei-Fei Xu Yun Ye Xiao-Ling Zhang Qiao Yang 《Marine drugs》2022,20(5)
Microalgae host varied microbial consortium harboring cross-kingdom interactions with fundamental ecological significance in aquatic ecosystems. Revealing the complex biofunctions of the cultivable bacteria of phycosphere microbiota is one vital basis for deeply understanding the mechanisms governing these dynamic associations. In this study, a new light-yellow pigmented bacterial strain LZ-28 was isolated from the highly-toxic and harmful algal bloom-forming dinoflagellate Alexandrium catenella LZT09. Collective phenotypic and genotypic profiles were obtained to confidently identify this strain as a new Mameliella alba member. Comparative genomic analysis showed that strain LZ-28 shared highly similar functional features with other four marine algae-derived M. alba strains in spite of their distinctive isolation sources. Based on the bioactivity assaying, the mutual growth-promoting effects between bacterial strain LZ-28 and algal strain LZT09 were observed. After the culture conditions were optimized, strain LZ-28 demonstrated an extraordinary production ability for its bioflocculanting exopolysaccharides (EPS). Moreover, the portions of two monosaccharides glucose and fucose of the EPS were found to positively contribute to the bioflocculanting capacity. Therefore, the present study sheds light on the similar genomic features among the selected M. alba strains, and it also reveals the potential pharmaceutical, environmental and biotechnological implications of active EPS produced by this new Mameliella alba strain LZ-28 recovered from toxic bloom-forming marine dinoflagellate. 相似文献
9.
10.