全文获取类型
收费全文 | 740篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
林业 | 42篇 |
农学 | 44篇 |
116篇 | |
综合类 | 48篇 |
农作物 | 107篇 |
水产渔业 | 56篇 |
畜牧兽医 | 333篇 |
园艺 | 9篇 |
植物保护 | 26篇 |
出版年
2023年 | 5篇 |
2022年 | 22篇 |
2021年 | 26篇 |
2020年 | 15篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 25篇 |
2016年 | 22篇 |
2015年 | 30篇 |
2014年 | 39篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 51篇 |
2010年 | 30篇 |
2009年 | 28篇 |
2008年 | 59篇 |
2007年 | 47篇 |
2006年 | 38篇 |
2005年 | 43篇 |
2004年 | 39篇 |
2003年 | 36篇 |
2002年 | 29篇 |
2001年 | 20篇 |
2000年 | 14篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1993年 | 2篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有781条查询结果,搜索用时 0 毫秒
91.
So Young Kim Myoung-Sook Shin Geum Jin Kim Hyukbean Kwon Myong Jin Lee Ah-Reum Han Joo-Won Nam Chan-Hun Jung Ki Sung Kang Hyukjae Choi 《Marine drugs》2021,19(8)
The epithelial–mesenchymal transition (EMT) of cancer cells is a crucial process in cancer cell metastasis. An Aquimarina sp. MC085 extract was found to inhibit A549 human lung cancer cell invasion, and caprolactin C (1), a new natural product, α-amino-ε-caprolactam linked to 3-methyl butanoic acid, was purified through bioactivity-guided isolation of the extract. Furthermore, its enantiomeric compound, ent-caprolactin C (2), was synthesized. Both 1 and 2 inhibited the invasion and γ-irradiation-induced migration of A549 cells. In transforming growth factor-β (TGF-β)-treated A549 cells, 2 inhibited the phosphorylation of Smad2/3 and suppressed the EMT cell marker proteins (N-cadherin, β-catenin, and vimentin), as well as the related messenger ribonucleic acid expression (N-cadherin, matrix metalloproteinase-9, Snail, and vimentin), while compound 1 did not suppress Smad2/3 phosphorylation and the expression of EMT cell markers. Therefore, compound 2 could be a potential candidate for antimetastatic agent development, because it suppresses TGF-β-induced EMT. 相似文献
92.
Takahisa YAMADA Seiki SASAKI Shin SUKEGAWA Takeshi MIYAKE Tatsuo FUJITA Hiroyuki KOSE Mitsuo MORITA Youichi TAKAHAGI Hiroshi MURAKAMI Fumiki MORIMATSU Yoshiyuki SASAKI 《Animal Science Journal》2009,80(4):486-489
Marbling, defined by the amount and distribution of intramuscular fat, is an economically important trait of beef cattle in Japan. The endothelial differentiation , sphingolipid G-protein-coupled receptor , 1 ( EDG1 ) gene has been considered as a positional functional candidate for the gene responsible for marbling. We have recently reported that 2 single nucleotide polymorphisms (SNPs), c.-312A > G in the 5' untranslated region (UTR) and c.*446G > A in the 3' UTR in EDG1 were associated with marbling in Japanese Black beef cattle, but this was not functional and a causal mutation for marbling. In the present study, we detected 2 novel SNPs, referred to as g.1475435G > A and g.1471620G > T , in the 5' flanking region of the EDG1 between low-marbled and high-marbled steer groups, which were previously shown to have EDG1 expression differences in musculus longissimus muscle. The g.1475435G > A SNP seemed not to segregate in Japanese Black beef cattle. The g.1471620G > T SNP was associated with the predicted breeding value for beef marbling standard number by the analyses using Japanese Black beef cattle population. Based on these findings, we hypothesized that the g.1471620G > T SNP might have an impact on EDG1 expression and also marbling. 相似文献
93.
We studied the effects of hyperhydricity on subcellular ultrastructure and physiology of leaves during in vitro regeneration of apple plants. Morphological, anatomical and ultrastructural differences between healthy leaf tissues obtained from greenhouse-grown plants and healthy and hyperhydric leaves obtained from shoots raised from nodal shoot explants in a bioreactor were investigated by electron microscopy and confocal laser scanning microscopy. Compared with healthy leaves, hyperhydric leaves showed abnormal, often discontinuous development of the epidermis and cuticle. Stomata were malformed. The leaf lamina appeared thickened and was characterized by poor differentiation between the palisade and spongy mesophyll tissue. Hyperhydric leaves had a significantly lower chloroplast number per cell and chloroplasts showed reduced thylakoid stacking compared with healthy leaves. Hyperhydricity resulted in a general decrease in concentrations of reduced and oxidized pyridine nucleotides, reflecting a reduction in metabolic activity. The activities of antioxidant enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase were higher in hyperhydric leaves than in healthy leaves, indicating that hyperhydricity was associated with oxidative stress. Chlorophyll fluorescence measurements provided evidence of oxidative damage to the photosynthetic machinery in hyperhydric leaves: photochemical efficiency of photosystem II, effective quantum efficiency and photochemical quenching were all lower in hyperhydric leaves compared with healthy leaves. 相似文献
94.
A melt-process was used to prepare high molecular weight Poly(vinyl chloride) (PVC) films without the use of a conventional
plasticizer and heat stabilizer. Rigid PVC powder was swollen with dimethylformamide containing 4∼10 vol% water to reduce
its melting temperature. The swollen powder was pressed at a relatively low temperature of 75∼125 °C to form a film shape,
and then washed and dried. The visible light transmittance, X-ray diffraction, density and the tensile properties of the resulting
films were examined to estimate the success or failure of film formation. The films could be produced by not only the melt-process
but also a compression-process using the rigid, highly swollen PVC powder. The resulting films had no voids, which are generally
observed in PVC products formed by a solution process. The minimum temperature for these processes decreased with decreasing
water content in the mixture: The minimum temperatures according to the water content in the mixture to produce faultless
films through the melt-process were 4 %–105 °C, 6 %–115 °C, 8 and 10 %–125 °C, while those through the compression process
were 4 %–95 °C, 6 and 8 %–105 °C, 10 %–115 °C. 相似文献
95.
Tae Joung Ha Jin Hwan Lee Sang-Ouk Shin Seong-Hyu Shin Sang-Ik Han Hyun-Tae Kim Jong-Min Ko Myong-Hee Lee Keum-Yong Park 《Journal of Crop Science and Biotechnology》2009,12(2):79-86
This study assessed the altitudinal variations in the anthocyanin and isoflavone contents of six black seed coated soybean
[Glycine max (L.) Merrill] cultivars. The black soybean cultivars Heugcheong, Seonheuk, Geomjeong 1, Geomjeong 2, Cheongja 2, and Cheongja
3 were planted at Milyang (12 m above mean sea level — low altitude) and Muju (600 m — high altitude), Korea on 10 June 2005
and 2006. The total anthocyanin and isoflavone contents and individual components were investigated by reverse-phase high
performance liquid chromatography (HPLC). All black soybean cultivars cultivated in high altitude possessed significantly
higher total anthocyanin (p < 0.01) and isoflavone (p < 0.01) contents than those grown in low altitude. For anthocyanin composition, cyanidin-3-O-glucoside, cyanidin-3-O-galactoside, and peonidin-3-O-glucoside contents were significantly higher while delphinidin-3-O-glucoside contents was significantly lower at high altitude. The composition of individual isoflavones, 6″-O-malonyldaidzin, and 6″-O-malonylgenistin contents significantly increased at high altitude. 相似文献
96.
本文介绍了茶产业集群的概念和中国茶产业集群发展的特征。中国茶产业集群发展兼具阶段性;自发性形成和外生性形成机制并存;茶产业效应从第一产业向第二、第三产业快速辐射效应明显。笔者就进一步促进中国茶产业集群的发展,提出了需要进一步加强的支持体系。 相似文献
97.
Taejo Kim Juan L. Silva Pramuk Parakulsuksatid Dja Shin Wang 《Journal Of Aquatic Food Product Technology》2013,22(4):385-393
One collagenase (CLS1®) and two proteases (Proleather FG-F® and Protease N®) were used to deskin the peritoneal membrane of catfish nuggets. The factors were used in a full factorial experiment design: enzyme solution concentration (0.2, 0.3, and 0.4% by weight), temperature of enzyme solution (30, 37, and 44°C), and immersion time (10, 15, and 20 min). Contour plots showed that the enzyme Proleather FG-F® maximized whiteness of catfish nuggets at 40–44°C for 15–19 min. Treatment of the enzyme Proleather FG-F® at 0.2% for 15 min had the highest yield (103.4%) at 44°C. Enzymatic skinning has potential in removing the peritoneal membrane from catfish nuggets, improving color (whiteness), and yield. 相似文献
98.
99.
Evaluation of dietary methionine requirement of male Korean native ducks for 3 weeks post‐hatching 下载免费PDF全文
Samiru S. Wickramasuriya Eunjoo Kim Taeg Kyun Shin Nu Ri Kim Jung Min Heo 《Animal Science Journal》2017,88(10):1595-1600
A total of 336 1‐day‐old male Korean native ducks (KND) were used in a completely randomized design with seven dietary methionine levels (0.30–0.90% with 0.1% increment) to determine the methionine requirement of male Korean native ducks for 3 weeks after hatching. Each dietary treatment had six replicates with eight ducklings per pen. One duckling from each pen (n = 6) was sacrificed to weigh empty body and drumsticks at the end of the experiment. Final body weight and weight gain of 3 weeks old KND were increased with increasing dietary methionine levels up to 0.4%, and then decreased (P < 0.05) with a further increasing dietary methionine level. In contrast, feed conversion ratio of the KND decreased up to 0.4% and increased (P < 0.05) with the increasing dietary methionine level. Both empty body weight and proportions of empty body weight were linearly increased (P < 0.05) while the dietary methionine level elevated up to 0.4%. Estimated dietary methionine requirement for maximum body weights, daily gain and minimum feed conversion ratio were 0.36, 0.39 and 0.40%, respectively, when it was fitted into linear‐ and quadratic‐plateau models. 相似文献
100.