全文获取类型
收费全文 | 263篇 |
免费 | 20篇 |
专业分类
林业 | 19篇 |
农学 | 10篇 |
基础科学 | 1篇 |
31篇 | |
综合类 | 13篇 |
农作物 | 7篇 |
水产渔业 | 44篇 |
畜牧兽医 | 146篇 |
园艺 | 1篇 |
植物保护 | 11篇 |
出版年
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 18篇 |
2014年 | 10篇 |
2013年 | 20篇 |
2012年 | 9篇 |
2011年 | 17篇 |
2010年 | 11篇 |
2009年 | 15篇 |
2008年 | 12篇 |
2007年 | 12篇 |
2006年 | 15篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1993年 | 1篇 |
1986年 | 2篇 |
1963年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有283条查询结果,搜索用时 31 毫秒
171.
皱缩型收缩是低中等密度桉树人工林木材被用于实木产品加工时最难以克服的缺陷之一.为此,本研究对种植在广西国营东门林场的3种易皱缩桉树(尾叶桉,巨桉,尾巨桉)木材的基本密度,微纤丝角(MFA),纤维双倍壁厚(DWT), 射线薄壁组织率(RP), 单位胞壁收缩率,总收缩率和残余皱缩几个与皱缩相关的材性指标进行了研究.结果表明:1)单位胞壁收缩率与基本密度具有极强的线性正相关性,与纤维双倍壁厚表现出中等至强的线性正相关性,而与射线薄壁组织率和微纤丝角呈现弱至中等的线性负相关性.基本密度能作为单独因子很好的预测单位胞壁收缩率(R2≥0.9412); 2)总收缩率与基本密度、纤维双倍壁厚、射线薄壁组织率具有弱至中等的线性正相关性,与微纤丝角呈现线性弱的负相关性.基本密度和上述3个解剖指标均不能单独作为预测总收缩率的因子(R2≤0.5712); 3)残余皱缩与基本密度和纤维双倍壁厚表现弱的线性负相关性,与微纤丝角呈现弱的线性正相关性,与射线薄壁组织率则表现了强的线性正相关性.因此,射线薄壁组织率是较好的残余皱缩的预测因子(R2≥0.7454). 相似文献
172.
Enkhbold BAZARRAGCHAA Takahiro HIONO Norikazu ISODA Hirotaka HAYASHI Masatoshi OKAMATSU Yoshihiro SAKODA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(11):1694
Sporadic spreads of swine-origin influenza H3N2 variant (H3N2v) viruses were reported in humans, resulting in 437 human infections between 2011 and 2021 in the USA. Thus, an effective vaccine is needed to better control a potential pandemic for these antigenically distinct viruses from seasonal influenza. In this study, a candidate vaccine strain with efficient growth capacity in chicken embryos was established through serial blind passaging of A/Indiana/08/2011 (H3N2)v in mice and chicken embryos. Seven amino acid substitutions (M21I in PA; A138T, N165K, and V226A in HA; S312L in NP; T167I in M1; G62A in NS1 proteins) were found in the passaged viruses without a major change in the antigenicity. This mouse- and egg-adapted virus was used as a vaccine and challenge strain in mice to evaluate the efficacy of the H3N2v vaccine in different doses. Antibodies with high neutralizing titers were induced in mice immunized with 100 µg of inactivated whole-virus particles, and those mice were significantly protected from the challenge of homologous strain. The findings indicated that the established strain in the study was useful for vaccine study in mouse models. 相似文献
173.
174.
175.
Hiroyuki Matsunari Hiroshi Hashimoto Kentaro Oda Yoshitsugu Masuda Hitoshi Imaizumi Kazuhisa Teruya Hirofumi Furuita Takeshi Yamamoto Kazuhisa Hamada Keiichi Mushiake 《Aquaculture International》2012,20(5):981-992
The effect of algae with different DHA contents used for the enrichment of rotifers on the growth performance, survival, and swim bladder inflation of larval amberjack Seriola dumerili was investigated. Rotifers were enriched with freshwater Chlorella vulgaris containing three levels of DHA (rotifer containing DHA 0.04, 0.60, 1.32?g DHA 100?g?1 DM) and Nannochloropsis (0.04?g DHA 100?g?1 DM; 2.54?g EPA 100?g?1DM). The larvae were fed the enriched rotifers in triplicate from 3?days post-hatch for 7?days in static condition. The same algae used for rotifer enrichment were supplied to the larval tanks. Growth and survival rate of fish fed the rotifers enriched with Nannochloropsis were higher than those of fish fed the rotifers enriched with all three Chlorella treatments. Swim bladder inflation was lowest in fish fed the rotifers enriched with Nannochloropsis. The proportion of EPA was higher in fish fed the rotifers enriched with Nannochloropsis, while that of DHA increased proportionally with the DHA levels in the rotifers enriched with Chlorella. These results suggest that rotifers enriched with Nannochloropsis (EPA-rich rotifers) are effective to enhance growth and survival, but DHA instead of EPA is essential to improve the swim bladder inflation in amberjack larvae. 相似文献
176.
Matsuda K Ohtsuka H Ichijho T Kawamura S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(1):75-77
The effect of dietary administration of bananas on immunocytes in calves was investigated. Twenty Fl hybrid calves were used in this study (treated group n=10, control group n=10). Banana (2 g/kg BW) was administered to the calves for 5 days. Leukocyte subsets were examined on days 0, 5, 10, and 15. The numbers CD3+, (CD3+)CD45R-, and (CD3+)TcR+ cells significantly increased between day 0 and day 5 in the treated group (P<0.01), and were significantly higher on day 5 in the treated group relative to the control group (P<0.05). These data showed that feeding banana to calves increased T-lymphocytes, suggesting it might be possible to enhance protective functions against infections. 相似文献
177.
Yoshinobu UEMOTO Takashi KIKUCHI Hikaru NAKANO Shuji SATO Tomoya SHIBATA Hiroshi KADOWAKI Kazuo KATOH Eiji KOBAYASHI Keiichi SUZUKI 《Animal Science Journal》2012,83(5):375-385
The leptin receptor (LEPR) gene is considered a candidate gene for fatness traits. It is located on SSC 6 in a region in which quantitative trait loci (QTLs) for backfat thickness (BF), fat area ratios, and serum leptin concentration (LEPC) have previously been detected in a Duroc purebred population. The objectives of the present study were to identify porcine LEPR polymorphisms and examine the effects of LEPR polymorphisms on fatness traits in this same population. The Duroc pigs (226 to 953 pigs) were evaluated for BF, fat area ratios using image analysis, and LEPC. A total of seven single nucleotide polymorphisms (SNPs) in the full‐length LEPR coding region were identified in pigs from the base population. Four non‐synonymous SNPs of the LEPR gene and 15 microsatellite markers on SSC 6 were then genotyped in all pigs. During candidate gene analysis, we detected significant effects of the non‐synonymous SNP c.2002C>T in exon 14 on all traits. In fine mapping analysis, significant QTLs for BF, fat area ratios, and LEPC were detected near the LEPR gene in the same region. These results indicated that the c.2002C>T SNP of LEPR has a strong effect on BF, fat area ratios and LEPC. 相似文献
178.
179.
Seiya MAEHARA Yoshiki ITOH Sho HOSHINO Miri HAYASHI Yosuke ITO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1335-1338
The purpose of this study was to evaluate the dark adaptation time in canine
electroretinography (ERG) using a contact lens electrode with a built-in LED. Twelve eyes
of six normal laboratory beagle dogs were used and exposed to steady room light at 500 lux
for 30 min for light adaption. ERG was recorded at different time points during dark
adaptation in sedated and light-adapted beagles. The stimulus intensity was 0.0096
cd/m2/sec. The b-wave amplitude increased significantly until 25 min of dark
adaptation, whereas no significant changes in amplitudes were observed after 30 min. Dark
adaptation for more than 25 min would be necessary for accurate ERG in canine ERG using a
contact lens electrode with a built-in LED. 相似文献
180.
Miyuki MORI Takeshi HAYASHI Yoshihiro ISOZAKI Naoki TAKENOUCHI Miki SAKATANI 《The Journal of reproduction and development》2015,61(5):423-429
In this study, the effect of heat shock on frozen-thawed blastocysts was evaluated using in
vitro-produced (IVP) bovine embryos. In experiment 1, the effects of 6 h of heat shock at 41.0 C on
fresh blastocysts were evaluated. HSPA1A expression as a reflection of stress was increased
by heat shock (P < 0.05), but the expressions of the quality markers IFNT and
POU5F1 were not affected. In experiment 2, frozen-thawed blastocysts were incubated at 38.5
C for 6 h (cryo-con) or exposed to heat shock at 41.0 C for 6 h (cryo-HS). Then, blastocysts were cultured at
38.5 C until 48 h after thawing (both conditions). Cryo-HS blastocysts exhibited a decreased recovery rate:
HSPA1A expression was dramatically increased compared with that in fresh or cryo-con
blastocysts at 6 h, and IFNT expression was decreased compared with that in cryo-con
blastocysts at 6 h (both P < 0.05). Cryo-con blastocysts at 6 h also exhibited higher
HSPA1A expression than fresh blastocysts (P < 0.05). At 48 h after thawing, the number
of hatched blastocysts and blastocyst diameter were lower in cryo-HS blastocysts (P < 0.05). Cryo-con
blastocysts showed lower POU5F1 levels at 48 h than fresh, cryo-con or cryo-HS blastocysts at
6 h (P < 0.05), but their POU5F1 levels were not different from those of cryo-HS
blastocysts at 48 h. These results indicated that application of heat shock to frozen-thawed blastocysts was
highly damaging. The increase in damage by the interaction of freezing-thawing and heat shock might be one
reason for the low conception rate in frozen-thawed embryo transfer in summer. 相似文献