全文获取类型
收费全文 | 167篇 |
免费 | 11篇 |
专业分类
林业 | 8篇 |
36篇 | |
综合类 | 9篇 |
农作物 | 3篇 |
水产渔业 | 29篇 |
畜牧兽医 | 71篇 |
园艺 | 1篇 |
植物保护 | 21篇 |
出版年
2023年 | 1篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 5篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 17篇 |
2003年 | 9篇 |
2002年 | 16篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有178条查询结果,搜索用时 15 毫秒
1.
Maria Caridad Montalvo Villalba Chantal J. Snoeck Licel de los Angeles Rodriguez Lay Aurélie Sausy Dayesi Hernández López Marite Bello Corredor Barbara Marrero Sanchéz Judith M. Hübschen 《Zoonoses and public health》2023,70(1):58-68
Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination. 相似文献
2.
This article addresses the German debate on the issue of the common welfare designation of public forests. In the first part,
drawing on two case studies, the political discourse on the issue is introduced. Two major competing ‘story lines’ can be
made out that are both based on a long tradition of controversially discussed concepts of regulatory forest policy. While
they both emphasise that common welfare services in forestry run counter to profit orientation, they fundamentally differ
with regard to the consequences for forest policy, e.g., considering the degree of state intervention. Afterwards, an overview
on the scientific debate on common welfare in the German context is given, and different concepts of common welfare determination
are distinguished. Existing approaches of common welfare determination in German forest policy are related to these concepts
and discussed. It is argued that the common welfare designation of the public forest is only insufficiently implemented by
the actual governance arrangements. Based on this consideration, eventually, the implementation of a procedural concept of
common welfare operationalisation in Germany’s public forests at the local level is proposed. While such a concept will not
solve all complex problems related to the determination of common welfare in public forestry, it would notably contribute
to a more operational definition of common welfare in public forestry and a more informed public debate on the issue. 相似文献
3.
Bergeron C Gafner S Clausen E Carrier DJ 《Journal of agricultural and food chemistry》2005,53(8):3076-3080
The aqueous extract of American skullcap (Scutellaria lateriflora L. (S. lateriflora), Lamiaceae) has been traditionally used by North American Indians as a nerve tonic and for its sedative and diuretic properties. Recent reports stated that flavonoids and possibly amino acids are responsible for the anxiolytic activity. As a part of our search for environmentally friendly solvents to extract the active components from medicinal plants, we used S. lateriflora in a comparison of accelerated solvent extraction (ASE) using water, and supercritical fluid extraction (SFE) using CO2 and 10% EtOH as modifier, at different temperatures. Flavonoids and amino acids were quantified by HPLC-UV and HPLC-MS, respectively. The flavonoid content was compared with conventional extraction methods (hot water extraction and 70% ethanol). The use of ASE at 85 degrees C with water as solvent gave the best results for flavonoid glycosides and amino acids, whereas SFE gave higher yields of flavonoid aglycones. However, the results obtained for total flavonoids were not significatively superior to hot water extraction or 70% aqueous EtOH extract. 相似文献
4.
Goutailler G Guillard C Faure R Païssé O 《Journal of agricultural and food chemistry》2002,50(18):5115-5120
The solar photolytic behavior of the pesticide 4,6-diamino-2-cyclopropyl-pyrimidine-5-carbonitrile, currently known as dicyclanil, has been mimicked in a photoreactor operating with an artificial light flux. The rate and pathway of degradation were performed. An additional study, using TiO(2) photocatalysis, has been achieved in order to determine the efficiency of photocatalysis to degrade the molecule. The catalyst was titania Degussa P-25. The aim of this article was the identification of the intermediate products formed during the irradiation, to establish the degradation pathway of dicyclanil. The kinetics of the reactions were followed by liquid chromatography with a diode array detector (LC-DAD). Most of the organic compounds occurring during the photodegradation have been identified by means of liquid chromatography and mass spectrometry coupled techniques (HPLC-MS). Additional analyses were carried out to evaluate the mineralization rates into nitrate and ammonium ions. 相似文献
5.
Patricia C. Duarte Cahuê F.R. Paz Alvaro P.L. Oliveira Thairê P. Maróstica Leticia O. Cota Rafael R. Faleiros 《Veterinary anaesthesia and analgesia》2017,44(4):943-950
Objective
To investigate the nociceptive and clinical effects of buffering a lidocaine–epinephrine solution with sodium bicarbonate in caudal epidural block in mares.Study design
Prospective randomized controlled trial.Animals
Six mixed-breed mares weighing 350–440 kg.Methods
Each animal was administered two caudal epidural injections, 72 hours apart, using different solutions prepared immediately before injection. The control solution was 7 mL 2% lidocaine hydrochloride with epinephrine hemitartrate (1:200,000) added to 3 mL sterile water for injection (pH 2.9). The alkalinized solution was 7 mL of lidocaine–epinephrine solution added to 2.3 mL sterile water for injection and 0.7 mL 8.4% sodium bicarbonate (pH 7.4). Nociception was evaluated by response to skin pinching at 31 sites in the sacral region and around the perimeter of the anogenital area (distances of 10, 15 and 20 cm) before, and 5, 10 and 15 minutes after epidural injection, then every 15 minutes until the return of nociception in all evaluated sites. The onset and duration times, and intensity of ataxia (grades 0 to 3) were recorded. The paired t test was used to compare the onset and duration of anesthesia and ataxia (p < 0.05).Results
Alkalization of the solution resulted in significant decreases in the average time of onset of loss of nociception in the sacral region (40%) and around the perimeter of the anogenital area extending up to 5 cm (36%) and from 5 to 10 cm (32%) from the anus and vulva. Alkalization also decreased the average duration of ataxia (33%), without affecting the duration and extent of anesthesia or the degree of ataxia.Conclusions and clinical relevance
Alkalization of lidocaine–epinephrine solution is advantageous in shortening the duration of ataxia and hastening the onset of anesthesia in areas adjacent to the anogenital area, without reducing the duration of epidural anesthesia, in mares. 相似文献6.
Gene expression pattern of digestive and antioxidant enzymes during the larval development of reared Atlantic bluefin tuna (ABFT), Thunnus thynnus L. 下载免费PDF全文
7.
The objective of this study is to identify possible causes of the high winter mortality noted in juvenile Mercenaria mercenaria notata in eastern Canada. The percentage mortality, shell growth, concentration of energy reserves, and production of cryoprotectant
molecules were compared between notata and native quahogs kept at intertidal and subtidal levels. Overwintering mortality
of the notata strain reached 47.2% and was 3–9 times higher than that of the native strain. Shell increment was higher in
the native than in the notata strain and also at the intertidal than at the subtidal level. The quahogs from the subtidal
zone had a higher concentration of protein than those from the intertidal zone in August and April but a lower concentration
in February. The notata strain had a lower concentration of lipids and glucose (34.9 and 0.21 mg g−1 dry weight) than the native strain (42.2 and 0.28 mg g−1 dry weight). Thermal hysteresis was detected in none of the quahog groups. High winter mortality in the notata strain seems
to be caused, in part, by a lower capacity to stock lipid compared with the native strain. The higher concentration of glucose
in the native strain may favour survival in cold water by helping to reduce the freezing point of the animals’ fluids. 相似文献
8.
9.
Castro SM Van Loey A Saraiva JA Smout C Hendrickx M 《Journal of agricultural and food chemistry》2004,52(18):5724-5729
Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 degrees C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 degrees C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55-57 degrees C) and a biphasic model for higher temperatures (58-70 degrees C). The enzyme showed a stable behavior toward high-pressure/temperature treatments. 相似文献
10.
Chantal Hamel Yolande Dalpé Claude Lapierre Régis R. Simard Donald L. Smith 《Biology and Fertility of Soils》1996,21(3):160-165
The dynamics of mycorrhizae under disturbance created by crop production is not well understood. A 3-year experiment was undertaken on a nutrient-poor and acidic land that had last been cultivated in the early 1970s. We observed the effects of cropping spring barley (Hordeum vulgare L.) under four P-fertilizer levels and four levels of lime, in a minimum (rototillage), a reduced (chisel), or a conventional tillage system, on the mycorrhizal receptiveness of the host (maximum level of mycorrhizal colonization, as measured at harvest) and soil infectivity most probable number method. The host receptiveness decreased with time, while crop yields and soil infectivity increased simultaneously with time. Liming increased mycorrhizal colonization of barley roots and soil infectivity. P additions decreased root colonization but did not significantly affect the most probable number valuse. Slightly higher soil infectivity estimates were found under reduced tillage. 相似文献