全文获取类型
收费全文 | 244篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
林业 | 25篇 |
农学 | 27篇 |
基础科学 | 4篇 |
48篇 | |
综合类 | 12篇 |
农作物 | 29篇 |
水产渔业 | 36篇 |
畜牧兽医 | 54篇 |
园艺 | 4篇 |
植物保护 | 15篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 26篇 |
2012年 | 20篇 |
2011年 | 17篇 |
2010年 | 19篇 |
2009年 | 4篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有254条查询结果,搜索用时 15 毫秒
101.
We performed desiccation and storage trials to better under- stand storage behavior of Knema attenuata seeds. Mature seeds with moisture content (MC) of 31% exhibited 73% germination. During the period of desiccation (open lab condition) seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10°C, 0°C, 10°C and 28±2°C (open lab condition) lost their viability within 10 days. Seeds stored in sealed polythene bags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage be- havior of K. attenuata seeds is recalcitrant. Seeds stored in moist condi- tions can, at best, be stored for a period of two months. 相似文献
102.
Lingyu Wang Arun S. Mujumdar Yingqiang Wang Chengpei Zhu 《Journal Of Aquatic Food Product Technology》2013,22(3):226-240
Restructured crispy fish cubes containing Salicornia bigelovii Torr. (S. bigelovii) were developed using microwave vacuum drying. A series of drying experiments and optimization experiments were conducted to optimize the process conditions of microwave vacuum drying. The quality parameters of fish cubes such as crispness, expansion ratio, and sensory score were measured. The optimal expansion ratio and crispness were decided on the basis of optimization experiments by response surface analysis. The results showed that the optimum microwave vacuum conditions were: initial moisture content of surimi was controlled at 60.5% (wet basis, w.b.) and microwave heating for 20 min at the vacuum pressure of 0.090 MPa and microwave power of 11 W/g. The final product had a uniform shape, homogenous texture, pleasant color, and delicious flavor. 相似文献
103.
Juan Wan Yingqiang Wang Arun S. Mujumdar Wang Yong-Jun 《Journal Of Aquatic Food Product Technology》2013,22(6):595-604
Salted grass carp fillets were dried by hot air drying (HD, at 35 and 45°C) and vacuum microwave drying (VMD, at 1, 4, and 7 W/g) to a final moisture content. Compared with hot air drying, the vacuum microwave drying greatly reduced drying time. The rehydration rate constant of salted grass carp fillets dried by microwave vacuum drying at 7-W/g microwave intensity was significantly higher than that of the hot air drying at 35 and 45°C. Compared with hot air drying, the vacuum microwave dried samples had a higher crude fat content (dry basis). The lightness of the samples dried by vacuum microwave drying was higher, and the yellowness was lower than those dried by hot air drying. The drying methods had no significant effect on the hardness and springiness. 相似文献
104.
L.A. Starkey A.W. Barrett M.J. Beall R. Chandrashekar B. Thatcher P. Tyrrell S.E. Little 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):552-555
Background
Ehrlichia ewingii, which causes disease in dogs and people, is the most common Ehrlichia spp. infecting dogs in the United States, but little is known about how long E. ewingii infection persists in dogs.Hypothesis/Objectives
To evaluate the persistence of natural infection with E. ewingii in dogs.Animals
Four Class A Beagles; no previous exposure to ticks or tick‐borne infectious agents.Methods
Dogs were exposed to ticks by weekly walks through tick habitat in north central Oklahoma; dogs positive for infection with Ehrlichia spp. by sequence‐confirmed PCR and peptide‐specific serology were evaluated for 733 days (D). Whole blood was collected once weekly for PCR, and serum was collected once monthly for detection of antibodies to Ehrlichia canis (peptide p16), Ehrlichia chaffeensis (indirect fluorescence antibody [IFA] and variable‐length PCR target [VLPT]), and E. ewingii (peptide p28).Results
All dogs (4/4) became infected with Ehrlichia spp. as evidenced by seroconversion on IFA to E. chaffeensis (4/4); PCR detection of E. ewingii (4/4) and E. chaffeensis (2/4) DNA using both nested and real‐time assays; and presence of specific antibodies to E. ewingii (4/4) and E. chaffeensis (2/4). Infection with E. chaffeensis was not detected after D55. Intermittent E. ewingii rickettsemia persisted in 3 of 4 dogs for as long as 733 days.Conclusions and Clinical Importance
Our data demonstrate that dogs infected with E. ewingii from tick feeding are capable of maintaining infection with this pathogen long‐term, and may serve as a reservoir host for the maintenance of E. ewingii in nature. 相似文献105.
Human filariasis caused by Brugia malayi is still a public health problem in many countries of Asia including India, Indonesia, Malaysia and Thailand. The World Health Organization (WHO) has targeted to eliminate filariasis by the year 2020 by Mass annual single dose Diethylcarbamazine Administration (MDA). Results of the MDA programme after the first phase was less satisfactory than expected. Malayan filariasis caused by B. malayi is endemic in the south of Thailand where domestic cat serves as the major reservoir host. There is no report about the occurrence of B. malayi in dogs. The present work was carried out to find out the incidence of microfilariasis in dogs and also to detect the presence of human filarial infection in dogs, if any. One hundred dogs above 6 months of age presented to the veterinary college Hospital, Mannuthy, Kerala, with clinical signs suggestive of microfilariasis - fever, anorexia, conjunctivitis, limb and scrotal oedema - were screened for microfilariae by wet film examination. Positive cases were subjected to Giemsa staining, histochemical staining and molecular techniques. Results of the study showed that 80% of dogs had microfilariasis; out of which 20% had sheathed microfilaria. Giemsa and histochemical staining character, PCR and sequencing confirmed it as B. malayi. High prevalence of B. malayi in dogs in this study emphasized the possible role of dogs in transmission of human filariasis. 相似文献
106.
Changing governance of the world's forests 总被引:3,自引:0,他引:3
Major features of contemporary forest governance include decentralization of forest management, logging concessions in publicly owned commercially valuable forests, and timber certification, primarily in temperate forests. Although a majority of forests continue to be owned formally by governments, the effectiveness of forest governance is increasingly independent of formal ownership. Growing and competing demands for food, biofuels, timber, and environmental services will pose severe challenges to effective forest governance in the future, especially in conjunction with the direct and indirect impacts of climate change. A greater role for community and market actors in forest governance and deeper attention to the factors that lead to effective governance, beyond ownership patterns, is necessary to address future forest governance challenges. 相似文献
107.
Poly(1,4-phenylene sulfide) (PPS) exhibits good dimensional stability and flame retardant characteristics but its commercial development as fibers is highly limited due to lesser dyeing and finishing characteristics. Hence in the present study, we focused on the anionic and cationic modifications of PPS to enhance its dyeing ability towards disperse, cationic, and anionic dyes. Novel sulfonation and chloromethylation-quaternization of PPS fiber were carried out to achieve an industrially viable dyeing process methodology. The chemically modified PPS fiber is dyed with disperse, cationic, and anionic dyes, and the dyeing adsorption efficiency is quantitatively studied using a dye-o-meter equipped with UV-visible absorption spectroscope. The ideal parameters for dye adsorption were determined as a function of dyeing time, material-toliquor ratio, dyeing temperature, carrier concentration, sulfonation, and chloromethylation. The fastness properties of the dyed fabrics were also studied. Overall, with a maximum dye uptake of 99 % and 90 % achieved for sulfonated PPS and quaternized PPS respectively, the optimized conditions can be readily scaled-up to the commercial dyeing of PPS fiber with disperse, anionic, and cationic dyes. 相似文献
108.
109.
M. Arun R. Radhakrishnan T.N. Ai A.H. Naing I.J. Lee 《The Journal of Horticultural Science and Biotechnology》2016,91(6):562-572
This study aimed to determine ways to improve the growth and salt tolerance of petunia. Effects of polyamines (PAs; spermidine [Spd], spermine [Spm], and putrescine [Put]) and a nitric oxide (NO) donor (sodium nitroprusside [SNP]) were investigated. Initially, we screened petunia cultivars against sodium chloride (0–125 mM). The petunia cultivar Hurrah Red was identified as salt-sensitive cultivar in the basis of salt-effect on seed germination, fresh weight, and root length of seedlings. Treatment of Hurrah Red shoots with nitrogenous compounds improved the number, length, and fresh weight of roots, as well as the length and fresh weight of shoots over those of the control. Furthermore, plantlets rooted in an optimal concentration of Spd (34.5 µM), Spm (24.8 µM), Put (62.1 µM), and SNP (3.9 µM) were treated with 200 mM NaCl for 3 days to assess their tolerance level. Salt-affected plantlets showed higher level of lipid peroxidation, reduced catalase (CAT), peroxidase (POD), polyphenol oxidase (PPO) activities and decreased contents of photosynthetic pigments and polyphenol than those of the control. PAs and SNP treatments significantly elevated photosynthetic pigments, enhanced antioxidant enzymes, and decreased lipid peroxidation in salt-stressed plantlets. Moreover, the growth and salt-tolerance response of petunia was highest when plantlets were exposed to SNP, followed by levels on treatment with Put, Spm, and Spd. Thus, the findings of this study suggested that treatment with exogenous SNP, Put, Spm, and Spd could protect petunia plants against soil salinity and improve their commercial production. 相似文献
110.
Wool fabrics, without any surface treatment, can undergo undesirable and irreversible structural changes of wool fiber during washing under heat and mechanical agitation, leading to high shrinkage of wool garments. The traditional method based on polyamide resin can prevent felting and/or shrinkage of wool textiles, but adversely affect the surface hydrophobicity. In the present study, a treatment solution was developed based on TriSilanolIsooctyl POSS® and 3- mercaptopropyl trimethoxysilane, which created wool surface with increased hydrophobicity and highly resistant to shrinkage or felting, as measured after 3×5A wash cycles (equivalent to 24 domestic washes). After the treatment, the wool fabric appeared to be superhydrophobic with a water contact angle of above 150°, compared to the untreated fabric. The treatment has marginal effect on mechanical performance as observed in tensile properties. Scanning electron microscopic images revealed a coating of POSS® on the wool surface. The dyeing of untreated and treated fabrics appeared to be uniform to the naked eye, though spectrophotometric analysis indicated a difference in the extent of dyeing performance. This research showed that POSS®-based treatment is a potentially effective approach for developing shrink-resistant wool textiles with enhanced surface hydrophobicity, in contrast to traditional chlorine/polyamide resin treatment. 相似文献