全文获取类型
收费全文 | 289篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
林业 | 27篇 |
农学 | 18篇 |
51篇 | |
综合类 | 9篇 |
农作物 | 5篇 |
水产渔业 | 18篇 |
畜牧兽医 | 146篇 |
园艺 | 2篇 |
植物保护 | 18篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 33篇 |
2012年 | 7篇 |
2011年 | 23篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 16篇 |
2007年 | 10篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1971年 | 4篇 |
1969年 | 1篇 |
1967年 | 2篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有294条查询结果,搜索用时 0 毫秒
291.
5-Reductase inhibitory activity of methanol extracts of the heartwood of 13 tropical wood species were examined. Strong 5-reductase inhibitory activity was observed withShorea species. From melapi (Shorea sp.), two known resveratrol trimers, vaticanol A and ampelopsin C, and two novel trimers were isolated as active compounds. The structures of the two novel resveratrol trimers were elucidated by one- and two-dimensional nuclear magnetic resonance spectroscopic analyses, including1H-1HCOSY, HMQC, and HMBC. The compounds were named melapinol A and melapinol B. There were no significant differences among the 5-reductase inhibitory activities of the four resveratrol trimers, which were significantly stronger than those of-linolenic acid and epigallocatechin gallate, known 5-reductase inhibitors. 相似文献
292.
Yasuhiro Suzuki Yoshio Sano Tetsuya Ishikawa Tomoko Sasaki Ushio Matsukura Hiro‐Yuki Hirano 《Cereal Chemistry》2003,80(2):184-187
The effects of environmental temperature (21 vs. 28°C) during rice seed development on the starch characteristics (apparent amylose content, amylopectin chain length distribution, and gelatinization properties) of nonwaxy Taichung 65 (T65), waxy Taichung (T65wx), du2‐2 mutated low‐amylose strain Taichung (76‐3/T65), and Koshihikari were studied. Amylose contents increased with decreasing environmental temperatures. Analysis of the amylopectin chain length distribution showed that the relative amounts of long chains with degree of polymerization (DP) > 25 in all starches decreased if maturation occurred at 21°C. Gelatinization onset, peak, and conclusion temperatures and enthalpies decreased with decreasing environmental temperatures. Of all starches studied, the du2‐2 mutated low‐amylose Taichung (76‐3/T65) was most affected by maturation temperatures. These results indicate that the du2‐2 mutated low‐amylose Taichung (76‐3/T65) may be a useful strain in understanding biochemical and genetic starch biosynthesis response to slight changes in temperature. 相似文献
293.
Naoko Miki Keiji Sakamoto Takashi Nishimoto Ken Yoshikawa Yoshio Hada 《Journal of Forest Research》2001,6(3):181-186
We examined the relationship between the incidence of pine wilt disease and moisture conditions in the stand level ofPinus densiflora Sieb. et Zucc. forests in the warm-temperate zone of the western part of Japan. For this analysis, pine trees killed by pine
wilt disease were distinguished from the suppressed trees by their position in the layer of the pine forest stand. The drainage
area, which is small in the upper part and large in the lower part of the slope, was adopted for representing the moisture
conditions in the soil of the slope. The percentage of the pine trees killed by pine wilt disease increased as the size of
the drainage area increased. This result suggested that the incidence of pine wilt disease tended to be high in areas with
moist conditions. Pine trees attacked by the pinewood nematode die from extensive water deficit due to tracheid cavitations.
Pine wilt disease mainly emerges in the summer when the soil water conditions become especially severe, and the radical water
stress is thought to accelerate the disease. It was assumed that pine trees in the plots with the small drainage area resisted
the influence of the attack of the pinewood nematode because pine trees in the plots with the small drainage area encountered
long-term water stress and acquired drought tolerance. Pine trees in the plots with the large drainage area were presumed
to be well established in the moist conditions and not to have acquired drought tolerance. The drought tolerance of pine trees
was thought to be an important factor in resistance to pine wilt disease. 相似文献
294.
Yoshio Kunimune Yasushi Mitsunaga Kazuyoshi Komeyama Masanari Matsuda Toru Kobayashi Tsutomu Takagi Takeshi Yamane 《Fisheries Science》2011,77(4):521-532
Seasonal habitat use by nigorobuna Carassius auratus grandoculis Temminck et Schlegel and gengoroubuna Carassius cuvieri (Temminck et Schlegel) in Lake Biwa was investigated using acoustic telemetry. Twenty-three nigorobuna and 11 gengoroubuna
specimens caught using set-nets in the lake’s south basin were surgically fitted with acoustic transmitters and then released.
Signals from the fishes were recorded by 23 receivers installed around the lake. Between April and June 2007, the first spawning
season after release, signals were received from all tagged fishes. Thereafter, until the second spawning season, signals
were collected from 26 and 45% of released nigorobuna and gengoroubuna individuals, respectively. Seasonal habitat preferences
for these species were studied by distance-based analysis. The analysis revealed that nigorobuna tended to stay near their
spawning area in the south basin of the lake throughout the year, whilst gengoroubuna tended to show a seasonal migration
pattern between the north and south basins. After the spawning season, the latter species migrated to the north basin where
it remained until the next spawning season, when it returned to the south basin. This is the first report of seasonal migration
of nigorobuna and gengoroubuna in Lake Biwa. 相似文献