全文获取类型
收费全文 | 211篇 |
免费 | 10篇 |
专业分类
林业 | 29篇 |
农学 | 10篇 |
基础科学 | 1篇 |
50篇 | |
综合类 | 15篇 |
农作物 | 11篇 |
水产渔业 | 22篇 |
畜牧兽医 | 49篇 |
园艺 | 10篇 |
植物保护 | 24篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 20篇 |
2013年 | 11篇 |
2012年 | 19篇 |
2011年 | 17篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 15 毫秒
61.
62.
Ewa Tomaszewska Siemowit Muszyski Piotr Dobrowolski Dariusz Wicek Agnieszka Tomczyk‐Warunek Izabela
wietlicka Stefan G. Pierzynowski 《Journal of animal physiology and animal nutrition》2019,103(2):626-643
It has been demonstrated in animal studies that prenatal administration of β‐hydroxy‐β‐methylbutyrate (HMB, metabolite of leucine) influences general growth and mechanical endurance of long bones in newborn offspring in sex‐dependent manner. The present experiment was conducted to evaluate the effect of HMB treatment of pregnant sows on bone development in offspring at weaning. From 70th day until the 90th day of gestation, sows received either a basal diet (n = 12) or the same diet supplemented with HMB (n = 12) at the dose of 0.2 g/kg of body weight/day. Femora obtained from six males and females in each group weaned at the age of 35 days were examined. Maternal HMB treatment significantly enhanced body weight and changed bone morphology increasing femur mechanical strength in both sexes. Maternal HMB supplementation also elevated bone micro‐ and macroelement concentrations and enhanced content of proteoglycans in articular cartilage. Based on the obtained results, it can be concluded that maternal HMB supplementation in the mid‐gestation period significantly accelerated bone development in both sexes by upregulation of a multifactorial system including leptin and osteoprotegerin. However, the sex (irrespective of the HMB treatment) was the factor which influenced the collagen structure in cartilages and trabecular bone, as demonstrated both by the Picrosirius red staining and performed analysis of thermal stability of collagenous tissues. The structural differences in collagen between males and females were presumably related to a different collagen maturity. No studies conducted so far provided a detailed morphological analysis of bone, articular cartilage, growth plate and the activities of the somatotropic and pituitary–gonadal axes, as well as leptin/osteoprotegerin system in weaned offspring prenatally treated with HMB. This study showed also the relationship between the maternal HMB treatment and bone osteometric and mechanical traits, hormones, and growth and bone turnover markers such as leptin, osteoprotegerin and insulin‐like growth factor‐1. 相似文献
63.
Studies were conducted on the effects of various kinds of teleost pituitary gonadotropins on the in vitro maturation of carp oocytes. It was ascertained that after 24 h of incubation with gonadotropins, the highest percentage of oocytes with the nucleus in the migrating or peripheral position, or of mature oocytes, was observed in the case of ciprinide gonadotropins.Centrifuged hypophysial homogenates of the pike, sea-trout and pike-perch displayed a considerably weaker activity. The results obtained are indicative of a specificity of teleost pituitary gonadotropins. 相似文献
64.
Susceptibility of apple genotypes from European genetic resources to fire blight (Erwinia amylovora)
65.
66.
Piotr Parasiewicz Elise L. King J. Angus Webb Mikoaj Piniewski Claudio Comoglio Christian Wolter Anthonie D. Buijse David Bjerklie Paolo Vezza Andreas Melcher Katarzyna Suska 《Fisheries Management and Ecology》2019,26(6):461-473
Floods and droughts are key driving forces shaping aquatic ecosystems. Climate change may alter key attributes of these events and consequently health and distribution of aquatic species. Improved knowledge of biological responses to different types of floods and droughts in rivers should allow the better prediction of the ecological consequences of climate change‐induced flow alterations. This review highlights that in unmodified ecosystems, the intensity and direction of biological impacts of floods and droughts vary, but the overall consequence is an increase in biological diversity and ecosystem health. To predict the impact of climate change, metrics that allow the quantitative linking of physical disturbance attributes to the directions and intensities of biological impacts are needed. The link between habitat change and the character of biological response is provided by the frequency of occurrence of the river wave characteristic—that is the event's predictability. The severity of impacts of floods is largely related to the river wave amplitude (flood magnitude), while the impact of droughts is related to river wavelength (drought duration). 相似文献
67.
Piotr Gąsiorek Daniel Stec Witold Morek Jamila Marnissi Łukasz Michalczyk 《African Zoology》2017,52(2):77-89
The current knowledge of the diversity and distribution of tardigrade species in northern Africa is scarce and far from satisfactory. In this paper we review old and provide new faunistic records for various regions of Tunisia. Among the newly recorded taxa, we found a new heterotardigrade Bryodelphax maculatus sp. nov. The new species belongs to the weglarskae group, characterised by the presence of ventral plates, but differs from its congeners by a different arrangement of ventral plates and by conspicuous groups of cuticular tubercles on the ventral cuticle. The analysis of larval, juvenile and mature instars of the new species revealed, for the first time in heterotardigrades, ontogenetic variability in the development of ventral armature.
http://zoobank.org/urn:lsid:zoobank.org:pub:7EA21201-8C74-4BFD-8EAF-A131A78805F0 相似文献
68.
Maria Skłodowska Ewa Gajewska Elżbieta Kuźniak Artur Mikiciński Piotr Sobiczewski 《Scientia Horticulturae》2010
BTH (S-methylbenzo-1,2,3-thiadiazole-7-carbothiate), an active compound of the commercial preparation Bion, has been studied as an elicitor of resistance to fire blight (Erwinia amylovora) in apple. However, the biochemical mechanisms of its action are not fully elucidated. Our study indicated that BTH at the best time of its protection activity (2–14 days after application) induced changes in prooxidant–antioxidant balance in the leaves of apple trees, but in different ways in the enzymatic and nonenzymatic antioxidants. Glutathione as low molecular antioxidant as well as superoxide anion radical and lipid peroxides as oxidants exhibited changes at the early phase of BTH action. Glutathione-dependent enzymes were strongly affected by the elicitor used. On the 2nd day glutathione transferase (GST) and glutathione peroxidase (GSH-Px) activities increased by about 70% and 30% above the control, respectively. GST activity normalized about the 14th day but GSH-Px at the same time showed 27% of the control value. Among enzymes utilising hydrogen peroxide only catalase showed increase (37%) at the early phase of experiment. Compared with the control, BTH-treated plants did not show changes in ascorbate peroxidase and phenylalanine ammonia-lyase activities. Tocopherol (TOC) level diminished starting from the 7th day after BTH treatment and on the 14th day it was only 28% of the control. It is proposed that extinguishing of BTH-mediated signal resulted from TOC and glutathione action. The diminished ascorbate level at all examined times may play a crucial role in BTH-mediated cell growth regulation. The direct influence of BTH on lipid metabolism should be also taken into consideration. 相似文献
69.
Wiesaw Przybylski Danuta Jaworska Piotr Saek Monika Sobol Maciej Branicki Grzegorz Skiba Stanisawa Raj Urszula Jankiewicz 《Journal of animal physiology and animal nutrition》2019,103(2):593-602
The aim of the study was to evaluate the influence of inulin supply to high‐fat diet rich in saturated fatty acids (SFA) on pork quality and profile of sarcoplasmic protein in drip loss. At 50 days of age, twenty cross‐bred pigs (gilts) were randomly allotted to four groups: the control (C) group fed a standard diet, and three experimental (D1, D2 and D3) groups fed a high‐fat diet rich in SFA. Moreover, pigs from the groups D2 and D3 consumed an extra inulin supply (7% of daily feed intake) from 85 to 120 days of age (for 5 weeks) and from 50 to 120 days of age (for 10 weeks) respectively. The addition of inulin to the diet reduced meaty odour and flavour significantly, improved tenderness and overall sensory quality of pork and additionally influenced ultimate pH, L* colour parameter, lactate level and protein content in meat. The diets also affected the profile of sarcoplasmic proteins. Significant effects were observed for the following enzymes—PK/PGI (pyruvate kinase/phosphoglucose isomerase) and ALD (aldolase), which are related to the intensity of post‐mortem glycolysis. Presented data indicate that long‐term inulin supply to high‐fat diet has a positive effect on technological and sensory quality as well as protein profile of pork. 相似文献
70.
Hamilton SR Bobrowicz P Bobrowicz B Davidson RC Li H Mitchell T Nett JH Rausch S Stadheim TA Wischnewski H Wildt S Gerngross TU 《Science (New York, N.Y.)》2003,301(5637):1244-1246
We report the humanization of the glycosylation pathway in the yeast Pichia pastoris to secrete a human glycoprotein with uniform complex N-glycosylation. The process involved eliminating endogenous yeast glycosylation pathways, while properly localizing five active eukaryotic proteins, including mannosidases I and II, N-acetylglucosaminyl transferases I and II, and uridine 5'-diphosphate (UDP)-N-acetylglucosamine transporter. Targeted localization of the enzymes enabled the generation of a synthetic in vivo glycosylation pathway, which produced the complex human N-glycan N-acetylglucosamine2-mannose3-N-acetylglucosamine2 (GlcNAc2Man3GlcNAc2). The ability to generate human glycoproteins with homogeneous N-glycan structures in a fungal host is a step toward producing therapeutic glycoproteins and could become a tool for elucidating the structure-function relation of glycoproteins. 相似文献