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261.
叶面施肥对提高库尔勒香梨抗寒相关性的研究 总被引:1,自引:2,他引:1
[目的]采用库尔勒香梨叶片为材料,进行叶面喷肥处理,研究其与提高香梨抗寒性的关系.[方法]通过磷钾肥、氮肥和硼肥进行3次6个不同浓度处理,在人工低温胁迫处理下测定枝条抗寒指标.[结果]各处理之间存在着极显著差异,其中PK2 、N1、N2处理抗寒效果好,各项指标含量均较高.整体分析各项抗寒指标来看,高浓度处理比低浓度处理效果好,硼肥处理没有明显效果.[结论]叶面喷肥处理浓度为0.3;的磷钾肥和0.2;、0.3;的氮肥处理效果较好,尤其是0.3;的磷钾肥在3个抗寒指标中含量均最高,且显著高于对照和其他处理区.各项指标普遍在低温胁迫-28℃时,各处理区处理的抗寒效果不明显.硼肥不能作为提高香梨树抗寒性的叶面肥使用. 相似文献
262.
Declan Tobin Esa A. Mäntysaari Dominic F. Houlihan Anders Kiessling Krisna Rungruangsak-Torrissen Kari Ruohonen 《Aquaculture (Amsterdam, Netherlands)》2006,261(2):510-521
Quantitative genetic analyses of fish composition have been strongly biased towards lipid deposition, rather than protein deposition. This is partly at odds with desires of the modern aquaculture industry, to improve the efficiency of lean growth. Using a quantitative genetic approach, we examined the selection potential in both protein and lipid components of wet weight growth in rainbow trout over a two-year growth period. Two diet treatments were applied to test the hypothesis that an experimental, high protein, low lipid diet (HP) would enhance selection potential compared to the current modern, normal protein, high lipid diet (NP). We found that lipid traits (lipid body weight, percent muscle and body lipid; h2 = 0.40) were more heritable than corresponding protein traits (protein body weight, percent muscle and body protein; h2 = 0.18), indicating a higher selection potential for lipid traits. The results revealed further that breeding for improved lipid composition over the whole growth period is easier than for protein composition. This was shown by the high favourable genetic correlations between differently aged fish for lipid traits. In contrast, the respective correlations for protein traits were low or even negative. Similarly, the genetic correlations between muscle and body composition were higher for lipid than for protein, enhancing selection efforts to change lipid traits. Heritabilities increased with age, implying that selection practiced on old (> 800 g) rather than young (< 60 g) fish should be more effective in achieving a compositional response. Although the diet had a significant effect on the composition traits, there was no general trend for diet differences in heritabilities of either protein or lipid traits. Thus, the hypothesis of increased selection potential on HP diet was not supported. In conclusion, lipid traits are both more variable and exhibit more favourable genetic architecture for selection compared to protein traits. 相似文献
263.
ystein Klakegg Takele Abayneh Aud Kari Fauske Michael Fülberth Henning Srum 《Journal of fish diseases》2019,42(6):789-807
An outbreak of disease characterized by skin ulcers, fin rot and mortality was observed a few days after the transfer of Atlantic salmon (Salmo salar) from a freshwater smolt production facility to a land‐based seawater post‐smolt site. Dead and moribund fish had severe skin and muscle ulcers, often 2–6 cm wide, particularly caudal to the pectoral fins. Microscopic examination of smears from ulcers and head kidney identified long, slender Gram‐negative rods. Histopathological analysis revealed abundance of long, slender Tenacibaculum‐like bacteria in ulcers and affected fins. Genetic characterization using multilocus sequence analysis (MLSA) of seven housekeeping genes, including atpA, dnaK, glyA, gyrB, infB, rlmN and tgt, revealed that the isolates obtained during the outbreak were all clustered with the Tenacibaculum dicentrarchi‐type strain (USC39/09T) from Spain. Two bath challenge experiments with Atlantic salmon and an isolate of T. dicentrarchi from the outbreak were performed. No disease or mortality was observed in the first trial. In the second trial with a higher challenge dose of T. dicentrarchi and longer challenge time, we got 100% mortality within 48 hr. This is the first reported outbreak of disease caused by T. dicentrarchi in Norwegian farmed Atlantic salmon. 相似文献
264.
The antibacterial lectin RegIIIgamma promotes the spatial segregation of microbiota and host in the intestine 总被引:1,自引:0,他引:1
Vaishnava S Yamamoto M Severson KM Ruhn KA Yu X Koren O Ley R Wakeland EK Hooper LV 《Science (New York, N.Y.)》2011,334(6053):255-258
The mammalian intestine is home to ~100 trillion bacteria that perform important metabolic functions for their hosts. The proximity of vast numbers of bacteria to host intestinal tissues raises the question of how symbiotic host-bacterial relationships are maintained without eliciting potentially harmful immune responses. Here, we show that RegIIIγ, a secreted antibacterial lectin, is essential for maintaining a ~50-micrometer zone that physically separates the microbiota from the small intestinal epithelial surface. Loss of host-bacterial segregation in RegIIIγ(-/-) mice was coupled to increased bacterial colonization of the intestinal epithelial surface and enhanced activation of intestinal adaptive immune responses by the microbiota. Together, our findings reveal that RegIIIγ is a fundamental immune mechanism that promotes host-bacterial mutualism by regulating the spatial relationships between microbiota and host. 相似文献
265.
Hirvonen T Tapanainen H Valsta L Hannila ML Aro A Pietinen P 《Public health nutrition》2006,9(6):792-797
OBJECTIVE: To examine the efficacy and safety of foods fortified with calcium in the adult population in Finland. DESIGN: A simulation study based on the FINDIET 2002 Survey, which estimated habitual food consumption, dietary supplement use and nutrient intakes using 48-hour recall and two 3-day food records, and an Internet survey of the consumption of fortified foods and dietary supplements. SETTING/PARTICIPANTS: Participants of FINDIET 2002 were 25-64 years old from five areas (n = 2007). Participants of the Internet-based survey (n = 1537) were over 15 years of age from all over the country. RESULTS: If all potentially fortifiable foods were to be fortified with calcium, the proportion of participants with calcium intake below the recommended level (< 800 mg day(-1)) would decrease from 20.3% to 3.0% in men and from 27.8% to 5.6% in women compared with the situation where no foods were fortified. At the same time, the proportion of participants with calcium intake above the tolerable upper intake level (UL, > 2500 mg day(-1)) would increase from 0.6% to 12.7% in men and from 0.1% to 3.8% in women. However, in a probability-based model (11% of all fortifiable foods to be fortified with calcium) the proportion of participants with calcium intake below the recommended level would be 15.7% in men and 23.2% in women. The proportion with intake above the UL in this model would be 1.2% in men and 0.7% in women. CONCLUSIONS: Food fortification would be a relatively effective and safe way to increase the calcium intake of the Finnish adult population. 相似文献
266.
267.
A series of wet‐cationized starch granules from waxy maize with different degrees of substitution (DS) were solubilized with either 2.2M HCl (lintnerization) or with the α‐amylase of Bacillus amyloliquefaciens. The maximum rate of the enzymatic hydrolysis occurred in starches with intermediate DS. It appeared that the cationic substituents interfered with the binding to the active site of the enzyme at high levels of substitution. The DS remained fairly constant in the granular residues after the enzymatic attack. The rate of the acidic hydrolysis increased with increasing DS but the final level of solubilization slightly decreased. The DS of the residual starch material decreased to 40% of the original level, showing that a large part of the cationic groups was found within the amorphous parts of the granules. A dry‐cationized sample with a high DS was also treated with the acid and lost a major part of its substituents at low levels of lintnerization. Probably most of the substituents were associated with the surface and channels of these granules. The cationized starches possessed branches that were resistant to isoamylase attack and the samples also contained β‐amylolysis resistant dextrins. The proportion of resistant dextrins in the granular residues decreased after lintnerization, but remained constant after the enzymatic hydrolysis. 相似文献
268.
Kari M. Tronsmo Ellen M. Magnus Pernille Baardseth J. David Schofield Anette Aamodt Ellen Mosleth Frgestad 《Cereal Chemistry》2003,80(5):587-595
The rheological properties of dough and gluten are important for end‐use quality of flour but there is a lack of knowledge of the relationships between fundamental and empirical tests and how they relate to flour composition and gluten quality. Dough and gluten from six breadmaking wheat qualities were subjected to a range of rheological tests. Fundamental (small‐deformation) rheological characterizations (dynamic oscillatory shear and creep recovery) were performed on gluten to avoid the nonlinear influence of the starch component, whereas large deformation tests were conducted on both dough and gluten. A number of variables from the various curves were considered and subjected to a principal component analysis (PCA) to get an overview of relationships between the various variables. The first component represented variability in protein quality, associated with elasticity and tenacity in large deformation (large positive loadings for resistance to extension and initial slope of dough and gluten extension curves recorded by the SMS/Kieffer dough and gluten extensibility rig, and the tenacity and strain hardening index of dough measured by the Dobraszczyk/Roberts dough inflation system), the elastic character of the hydrated gluten proteins (large positive loading for elastic modulus [G′], large negative loadings for tan δ and steady state compliance [Je0]), the presence of high molecular weight glutenin subunits (HMW‐GS) 5+10 vs. 2+12, and a size distribution of glutenin polymers shifted toward the high‐end range. The second principal component was associated with flour protein content. Certain rheological data were influenced by protein content in addition to protein quality (area under dough extension curves and dough inflation curves [W]). The approach made it possible to bridge the gap between fundamental rheological properties, empirical measurements of physical properties, protein composition, and size distribution. The interpretation of this study gave indications of the molecular basis for differences in breadmaking performance. 相似文献
269.
Kari M. Tronsmo Ellen Merethe Magnus Ellen Mosleth Frgestad J. David Schofield 《Cereal Chemistry》2003,80(5):575-586
The rheological properties of fresh gluten in small amplitude oscillation in shear (SAOS) and creep recovery after short application of stress was related to the hearth breadbaking performance of wheat flours using the multivariate statistics partial least squares (PLS) regression. The picture was completed by dough mixing and extensional properties, flour protein size distribution determined by SE‐HPLC, and high molecular weight glutenin subunit (HMW‐GS) composition. The sample set comprised 20 wheat cultivars grown at two different levels of nitrogen fertilizer in one location. Flours yielding stiffer and more elastic glutens, with higher elastic and viscous moduli (G′ and G″) and lower tan δ values in SAOS, gave doughs that were better able to retain their shape during proving and baking, resulting in breads of high form ratios. Creep recovery measurements after short application of stress showed that glutens from flours of good breadmaking quality had high relative elastic recovery. The nitrogen fertilizer level affected the protein size distribution by an increase in monomeric proteins (gliadins), which gave glutens of higher tan δ and flatter bread loaves (lower form ratio). 相似文献