全文获取类型
收费全文 | 29093篇 |
免费 | 1094篇 |
国内免费 | 2篇 |
专业分类
林业 | 4714篇 |
农学 | 1748篇 |
基础科学 | 193篇 |
5804篇 | |
综合类 | 1482篇 |
农作物 | 2593篇 |
水产渔业 | 2799篇 |
畜牧兽医 | 6494篇 |
园艺 | 1335篇 |
植物保护 | 3027篇 |
出版年
2023年 | 155篇 |
2022年 | 162篇 |
2021年 | 345篇 |
2020年 | 350篇 |
2019年 | 244篇 |
2018年 | 3163篇 |
2017年 | 3134篇 |
2016年 | 1729篇 |
2015年 | 553篇 |
2014年 | 611篇 |
2013年 | 882篇 |
2012年 | 1823篇 |
2011年 | 2967篇 |
2010年 | 2509篇 |
2009年 | 1593篇 |
2008年 | 2076篇 |
2007年 | 2277篇 |
2006年 | 676篇 |
2005年 | 784篇 |
2004年 | 698篇 |
2003年 | 716篇 |
2002年 | 507篇 |
2001年 | 310篇 |
2000年 | 308篇 |
1999年 | 237篇 |
1998年 | 75篇 |
1997年 | 65篇 |
1996年 | 49篇 |
1995年 | 65篇 |
1994年 | 40篇 |
1993年 | 47篇 |
1992年 | 88篇 |
1991年 | 69篇 |
1990年 | 66篇 |
1989年 | 67篇 |
1988年 | 63篇 |
1987年 | 49篇 |
1986年 | 48篇 |
1985年 | 51篇 |
1984年 | 44篇 |
1983年 | 35篇 |
1979年 | 36篇 |
1974年 | 29篇 |
1973年 | 21篇 |
1972年 | 23篇 |
1971年 | 23篇 |
1970年 | 27篇 |
1969年 | 27篇 |
1968年 | 29篇 |
1967年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
106.
107.
Physiological Response of Multiple Contrasting Rice (Oryza sativa L.) Cultivars to Suboptimal Temperatures
下载免费PDF全文
![点击此处可从《Journal of Agronomy and Crop Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. M. Rachoski A. Vidal O. A. Ruiz A. B. Menéndez A. A. Rodríguez 《Journal of Agronomy and Crop Science》2015,201(2):117-127
The physiological response of multiple rice cultivars, eighteen initially and eight cultivars later on, to suboptimal temperatures (ST) conditions was investigated in laboratory and outdoor experimental conditions. Treatment with ST decreased growth in different extents according to the cultivar and affected the PSII performance, determined by chlorophyll fluorescence fast‐transient test, and stomatal conductance, regardless the experimental condition. Two groups of cultivars could be distinguished on the base of their growth and physiological parameters. The group of cultivars presenting higher growths displayed optimal JIP values, and higher instantaneous water use efficiency (WUEi), due to a lower Gs under ST, unlike cultivars showing lower growth values, which presented worse JIP values and could not adjust their Gs and hence their WUEi. In this work, we detected at least two cultivars with superior tolerance to ST than the cold tolerant referent Koshihikari. These cultivars could be used as parents or tolerance donors in breeding for new crop varieties. On other hand, positive and significant correlations between data obtained from laboratory and outdoor experiments suggest that laboratory measurements of most of the above mentioned parameters would be useful to predict the response of rice cultivars to ST outdoor. 相似文献
108.
Isabel Oliveira Cosentino Mario Felipe Alvarez Balaro Felipe Seabra Cardoso Leal Lucas de Figueiredo Cardoso Barbosa Fernanda Martins Gonçalves Gabriel Feliciano Felizardo Marina Monteiro Netto Felipe Zandonadi Brandão 《Reproduction in domestic animals》2020,55(11):1655-1659
This study aimed to evaluate the exogenous progesterone (P4) effect on the luteal function from Day 16 to Day 21 of the oestrous cycle in inseminated goats with unknown pregnancy status. A total of 54 does passed through a short progestin-based synchronization protocol and, on Day 16 of the following oestrous cycle, 27 does received a new P4 device which was retained until Day 21. Blood samples were collected daily from all does during this period, as well as on Day 24. Pregnancy diagnoses were performed on Day 30. Serum P4 values from 26 animals (GNPSP: Group of non-pregnant does with second sponge: n = 8; GNPNSP: Group of non-pregnant does without second sponge: n = 6; GPSP: Group of pregnant does with second sponge: n = 5; GPNSP: Group of pregnant does without second sponge: n = 7) were determined by radioimmunoassay commercial kits. No P4 differences were found between groups (GNPSP: 3.1 ± 2.8; 1.7 ± 1.8; 0.4 ± 1.0; and 0.0 ± 0.0 vs. GNPNSP: 4.4 ± 1.8; 3.0 ± 2.2; 0.8 ± 0.8; and 0.0 ± 0.0 or GPSP: 4.2 ± 1.0; 3.4 ± 0.6; 3.3 ± 1.6; 3.2 ± 0.9; 3.6 ± 1.2; 3.5 ± 1.3; 2.7 ± 1.3 vs. GPNSP: 4.4 ± 1.6; 3.6 ± 1.5; 3.7 ± 1.5; 3.8 ± 1.4; 3.2 ± 1.2; 3.1 ± 1.2; 3.6 ± 1.1; D16, D17, D18, D19, D20, D21, D24, respectively) or for the interaction of group and time. In conclusion, a second progestogen device had no effect on luteolysis or early pregnancy in the following oestrous cycle. 相似文献
109.