全文获取类型
收费全文 | 701篇 |
免费 | 39篇 |
专业分类
林业 | 69篇 |
农学 | 29篇 |
基础科学 | 4篇 |
170篇 | |
综合类 | 45篇 |
农作物 | 39篇 |
水产渔业 | 60篇 |
畜牧兽医 | 236篇 |
园艺 | 18篇 |
植物保护 | 70篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 10篇 |
2021年 | 28篇 |
2020年 | 38篇 |
2019年 | 32篇 |
2018年 | 30篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 17篇 |
2014年 | 36篇 |
2013年 | 39篇 |
2012年 | 47篇 |
2011年 | 56篇 |
2010年 | 28篇 |
2009年 | 32篇 |
2008年 | 51篇 |
2007年 | 46篇 |
2006年 | 24篇 |
2005年 | 28篇 |
2004年 | 26篇 |
2003年 | 33篇 |
2002年 | 28篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 3篇 |
排序方式: 共有740条查询结果,搜索用时 15 毫秒
91.
Significant improvement of shrimp growth performance by growth hormone‐releasing peptide‐6 immersion treatments 下载免费PDF全文
Amílcar Arenal Juana María Lugo Reynold Morales Leonardo Martín Ramón Franco Rodríguez Jannel Acosta Antonio Morales Jorge Duconge Mario Pablo Estrada 《Aquaculture Research》2017,48(9):4632-4645
Growth hormone‐releasing peptide‐6 (GHRP‐6) is one of the earliest developed synthetic peptidyl growth hormone secretagogue receptor agonists. These compounds mimic the effect of the endogenous ligand ghrelin. In vertebrates, ghrelin is a potent circulating orexigenic hormone with functional roles in controlling food intake, energy expenditure, adiposity, growth hormone secretion and immunity. Ghrelin has been studied mainly in vertebrates; thus, little is known about its role in invertebrates, including crustaceans. We first evaluated the effect of GHRP‐6 injection over feed intake in shrimp and its effects on shrimp growth when the peptide was administrated by successive immersion baths. GHRP‐6 increased feed intake, body weight and size, the number of rostral spines and gill branches, protein concentration and haemocyte number in treated shrimps. We also evaluated the peptide uptake and clearance in a pharmacokinetics, using [H3]GHRP‐6 administered to postlarvae. Given a limited exposure and efficient clearance of the peptide‐associated radioactivity from larvae, our findings suggested that GHRP‐6‐treated Litopenaeus vannamei can be consumed safely by humans after aquaculture applications. These results propose that GHRP‐6 could be an additional tool to study growth physiology in crustaceans and also a promising candidate for development into a new biotechnology product for improving shrimp growth and quality. 相似文献
92.
Mario A. Burgos-Aceves Rafael Campos-Ramos Danitzia A. Guerrero-Tortolero 《Fish physiology and biochemistry》2010,36(4):1263-1269
The peripheral blood cells and differential blood profile of captive female and male leopard grouper Mycteroperca
rosacea are described for aquacultural purposes. Basophilic, polychromatic, and orthochromic erythroblasts were observed as immature
erythrocytes that develop into mature erythrocytes. Young erythrocytes were not evident, and bi-lobed erythrocytes were extremely
scarce. Types of leukocytes included lymphocytes; three types of granulocytes (basophiles, eosinophiles, and neutrophiles);
monocytes; and a specialized amoeboid-like macrophage in the blood, which has not been previously described in fish-blood
literature. Thrombocytes were commonly observed. There was significantly higher erythropoiesis in males. Granulocytes and
lymphocytes of females were significantly higher than males, whereas monocytes and thrombocytes were not. 相似文献
93.
94.
Margarita P. Gonzlez Gmez Loreto Ovalle Mylena Menanteau Claudia Spinetto Renato Oyarzún Mario Rivas Cristian Oyarzo 《Journal of fish diseases》2019,42(8):1143-1149
A major challenge for Chilean salmon farming is infestation by the ectoparasite Caligus rogercresseyi. In addition, there is evidence that a loss of chemotherapeutic treatment efficacy against important fish pathogens is occurring in salmon farming, including antiparasitic efficacy. Currently, there are known techniques that allow the determination of the susceptibility profile of parasites to antiparasitic treatment. However, there is scarce information about both threshold values and categorization of antiparasitic susceptibility for C. rogercresseyi. Bioassay technique allowed the determination of both mean values and the natural variation of EC50%, which were contrasted with available susceptibility thresholds. Results allowed to determine that parasites from the native fish host, Eleginops maclovinus, are susceptible to azamethiphos, deltamethrin and cypermethrin treatments, showing a high susceptibility profile to antiparasitics. 相似文献
95.
Rmi Cousin Hugo Groult Chanez Manseur Romain Ferru-Clment Mario Gani Rachel Havret Claire Toucheteau Grgoire Prunier Batrice Colin Franck Morel Jean-Marie Piot Isabelle Lanneluc Kvin Baranger Thierry Maugard Ingrid Fruitier-Arnaudin 《Marine drugs》2021,19(10)
Sugar-based molecules such as heparins or natural heparan sulfate polysaccharides have been developed and widely studied for controlling heparanase (HPSE) enzymatic activity, a key player in extracellular matrix remodelling during cancer pathogenesis. However, non-enzymatic functions of HPSE have also been described in tumour mechanisms. Given their versatile properties, we hypothesized that sugar-based inhibitors may interfere with enzymatic but also non-enzymatic HPSE activities. In this work, we assessed the effects of an original marine λ-carrageenan derived oligosaccharide (λ-CO) we previously described, along with those of its native counterpart and heparins, on cell viability, proliferation, migration, and invasion of MDA-MB-231 breast cancer cells but also of sh-MDA-MB-231 cells, in which the expression of HPSE was selectively downregulated. We observed no cytotoxic and no anti-proliferative effects of our compounds but surprisingly λ-CO was the most efficient to reduce cell migration and invasion compared with heparins, and in a HPSE-dependent manner. We provided evidence that λ-CO tightly controlled a HPSE/MMP-14/MMP-2 axis, leading to reduced MMP-2 activity. Altogether, this study highlights λ-CO as a potent HPSE “modulator” capable of reducing not only the enzymatic activity of HPSE but also the functions controlled by the HPSE levels. 相似文献
96.
Ioannis E. Papadakis Mario M. Zaiss Yiannos Kyriakou Georgios Georgiou Pascal Divanach Constantinos C. Mylonas 《Aquaculture (Amsterdam, Netherlands)》2009,286(1-2):45-52
The influence of the absence of Artemia nauplii from larval diet protocols on growth and digestive system ontogeny was studied using histological techniques in the shi drum (Umbrina cirrosa). One group of larvae was reared using the standard intensive rearing protocol, which offers a combination of enriched rotifers (Brachionus plicatilis), Artemia spp. nauplii and artificial diet (Std-group). Another group was reared using the same protocol, but without the offering of Artemia nauplii (group No-Artemia). The ontogenesis of the digestive system from hatching to metamorphosis was a very rapid process, and there were no differences between the two feeding regimes in the temporal appearance of the various components of the digestive system. The first organised presence of the hepatic and pancreatic tissue appeared at 2–3 d after hatching (dah), suggesting that these organs function from a very early developmental stage. In the No-Artemia larvae between 13 and 29 dah there was a reduction in the height of enterocytes in the intestinal mucosa, a progressive flattening of the primary intestinal folds in the anterior and posterior intestine and a decrease in lipid stores in the liver, suggesting a period of relative starvation. However, by the end of the study at 41 dah, there were no significant differences in body length, intestinal morphology or liver lipid stores between larvae reared under the two feeding regimes. The study suggests that the diet may influence the maturation and/or function, but not the ontogeny of the digestive system. Furthermore, the rapid differentiation of the digestive system in shi drum and the prompt recovery of the No-Artemia larvae from the symptoms of starvation by 29 dah, indicate a plasticity during ontogenesis and the ability of larvae to adapt to artificial diets at very early developmental stages. 相似文献
97.
Gaëlle Roudaut Mario Maglione Dagmar van Dusschoten Martine Le Meste 《Cereal Chemistry》1999,76(1):70-77
The molecular mobility in low-moisture (<9%, web) white bread was studied as a function of temperature using pulsed-proton nuclear magnetic resonance (NMR), and dielectric and dynamic mechanical spectroscopies. The water was mobile, even in glassy samples. Different processes below glass transition temperature (sub-Tg) were observed, and a relaxation map of the studied system was drawn. These results have been interpreted and extrapolated to suggest that the Tg is not a universal predictive parameter for the physical stability of glassy food. 相似文献
98.
Early life history connectivity of Antarctic silverfish (Pleuragramma antarctica) in the Ross Sea 下载免费PDF全文
Cassandra M. Brooks Jilda Alicia Caccavo Julian Ashford Robert Dunbar Kimberly Goetz Mario La Mesa Lorenzo Zane 《Fisheries Oceanography》2018,27(3):274-287
A recent population hypothesis for Antarctic silverfish (Pleuragramma antarctica), a critical forage species, argued that interactions between life history and circulation associated with glacial trough systems drive circumpolar distributions over the continental shelf. In the Ross Sea, aggregations of eggs and larvae occur under fast ice in Terra Nova Bay, and the hypothesis predicted that dispersing larvae encounter outflow along the western side of Drygalski Trough. The outflow advects larvae towards the shelf‐break, and mixing with trough inflow facilitates return toward the inner shelf. To examine the hypothesis, we compared samples of P. antarctica collected near Coulman Island in the outflow, along Crary Bank in the inflow, and a third set taken over the rest of the Ross Sea. We ruled out misidentification using an innovative genetic validation. Silverfish larvae comprised 99.5% of the catch, and the highest population densities were found in Drygalski Trough. The results provided no evidence to reject the population hypothesis. Abundance indices, back‐calculated hatching dates, length distributions and growth were congruent with a unified early life history in the western Ross Sea, constrained by cryopelagic early stages in Terra Nova Bay. By contrast, a sample in the Bay of Whales revealed much smaller larvae, suggesting either a geographically separate population in the eastern Ross Sea, or westward connectivity with larvae spawned nearby by fish sourced from troughs upstream in the Amundsen Sea. These results illustrate how hypotheses that integrate population structure with life history can provide precise spatial predictions for subsequent testing. 相似文献
99.
Patrícia Pereira Machado Fábio Steiner Alan Mario Zuffo Rafael Alves Machado 《Potato Research》2018,61(2):169-182
The adequate supply of boron (B) and zinc (Zn) can improve the structural integrity and permeability of cell membranes, which is a defence mechanism against fungi infection. A greenhouse experiment was conducted to investigate the effect of the application of B and Zn on plant growth and the incidence and severity of potato early blight, a destructive foliar disease of potato crop caused by Alternaria grandis E.G. Simmons. Potato plants (Solanum tuberosum L. cv. Ágata) were grown in 11-l pots filled with sandy soil, unfertilized or fertilized with 5 mg kg?1 B and 5 mg kg?1 Zn (either alone or in combination). Potato plants were inoculated with isolates of Alternaria grandis at 40 days after planting. Early blight incidence and severity were evaluated visually 7 days after inoculation with A. grandis isolates. Disease incidence ranged from 16 to 41% infected leaves, and was significantly highest in the treatment with the application of B, followed by the control, and lowest with application of Zn and B + Zn. Early blight severity ranged from 2.5 to 25%, and was significantly higher in the unfertilized treatment than in those fertilized with Zn either alone or in combination with B. These findings suggest that Zn plays a critical role in potato tolerance to early blight and should be considered as a preventive measure in the disease management plan, since application of zinc reduced the incidence and severity of potato early blight. However, the physiological basis of this remains unknown. 相似文献
100.