全文获取类型
收费全文 | 190篇 |
免费 | 14篇 |
专业分类
林业 | 5篇 |
农学 | 16篇 |
基础科学 | 5篇 |
78篇 | |
综合类 | 9篇 |
农作物 | 23篇 |
水产渔业 | 6篇 |
畜牧兽医 | 31篇 |
园艺 | 6篇 |
植物保护 | 25篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 1篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 7篇 |
2009年 | 13篇 |
2008年 | 13篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1940年 | 1篇 |
排序方式: 共有204条查询结果,搜索用时 18 毫秒
1.
Hokonohara S Singh UM Jha VC Pradhan A Dev S Mandar RK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(6):719-722
A buffalo disease, called "Degnala", causing lameness, edema, gangrenous ulceration of hooves or tail, emaciation, recumbency and eventual death, occurs in Eastern Nepal. Clinical examinations manifested lice eggs on hairs, bradycardia, hypothermia, dehydration, exanthema and icterus. Hematologically, increase of band neutrophil, giant platelet, hypoalbuminemia and hyperglobulinemia were characteristics. Microscopically, dark blue tiny particles were seen on red blood cell (RBC) after Giemsa staining. Administration of tetracycline at an early stage of the disease was effective. 相似文献
2.
The physical properties of fruit are important in designing and fabricating equipment and structures for handling, transporting, processing and storage, and also for assessing quality. The study was conducted to investigate some physical properties of jatropha fruit at various moisture levels. The average length, width, thickness and 1000 mass were 29.31 mm, 22.18 mm, 21.36 mm and 1522.10 g, respectively, at moisture content of 7.97% d.b. The geometric mean diameter increased from 24.03 to 24.70 mm and the sphericity varied between 0.82 and 0.83 as moisture content increased from 7.97% to 23.33% d.b., respectively. In the same moisture range, the bulk and true densities decreased from 278 to 253 and 546 to 435 kg m?3, respectively, whereas the corresponding porosity also decreased from 49.08% to 41.84%. As the moisture content increased from 7.97% to 23.33% d.b., crushing strength was decreased from 275 to 79 N, whereas the angle of repose and surface areas were found to increase from 36.41° to 41.72° and 1815.73 to 1917.59 mm2, respectively. The static coefficient of friction of jatropha fruit increased linearly against the surfaces of three structural materials, namely plywood (47.81%), mild steel (62.88%) and aluminium (34.82%) as the moisture content increased from 7.97% to 23.33% d.b. 相似文献
3.
4.
In the present study, nanofibrils of cellulose are extracted from waste jute fibers using high energy planetary ball milling process in wet condition. The rate of refinement of untreated fibers having non-cellulosic contents was found slower than treated fibers due to strong holding of fiber bundles by non-cellulosic contents. At the end of three hours of wet milling, untreated fibers were refined to the size of 850 nm and treated fibers were refined to the size of 443 nm. In the subsequent stage, composite films of poly lactic acid (PLA) were prepared by solvent casting with 3 wt% loading of untreated jute nanofibrils, treated jute nanofibrils and microcrystalline cellulose. The influence of non-cellulosic contents on mechanical properties of PLA films are investigated based on results of tensile test, dynamic mechanical analysis and differential scanning calorimetry. The maximum improvement was observed in case of treated jute nanofibril/PLA composite film where initial modulus and tensile strength increased by 207.69 % and 168.67 %, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction of treated jute nanofibrils with PLA matrix due to their higher precentage of cellulosic contents and mechanically activated surface. 相似文献
5.
Vishal Mishra Chandrajit Balomajumder Vijay Kumar Agarwal 《Water, air, and soil pollution》2010,209(1-4):489-500
Present research has delineated the biosorption potential of three different nonliving biomasses namely eucalyptus bark saw dust, mango bark saw dust, and pineapple fruit peel with respect to Zn (II) ion removal from liquid phase through batch experiments. The efficacy of Zn (II) ion biosorption onto surface of biosorbents was judged and correlated with biosorbent particle size, surface chemistry, and surface texture. Maximum metal ion uptake capacity, percentage removal, and minimum equilibrium concentration as 1.688 mg/g, 84.4%, and 1.56 mg/l, respectively, was obtained using eucalyptus bark saw dust mediated biosorption followed by mango bark saw dust as 1.028 mg/g, 51.4%, and 4.867 mg/l and pineapple fruit peel as 0.45 mg/g, 22.9%, and 7.71 mg/l, respectively, at a particle size of 0.5 mm. Additionally, present investigation also proved that biosorption efficiency and metal ion interaction with adsorbent surface also depends upon presence of functional groups involved in metal ion adsorption and surface porosity. 相似文献
6.
Studies on reproductive biology are difficult but useful in species like Aegle marmelos (Linn.) Correa which is of considerable socio-economic importance and possess morphogenetic variation and qualities of wider
adaptability to different soils. Cytology, phenology, pollination, breeding system and natural regeneration of wild and cultivated
trees from India revealed the existence of diploid (2n = 18) and tetraploid trees (2n = 36) in Pachmarhi hills and only diploid
trees in Punjab plains and Shiwalik hills. The diploid and tetraploid trees showed normal meiosis and high pollen fertility.
Phenological events which included leaf fall, leaf emergence, floral bud break, flowering and fruiting are nearly the same
in wild and cultivated trees. Natural pollen transfer in the species was highly efficient. Levels of fruit set following open
pollination was quite high and is reduced considerably following hand pollination probably due to some injury caused to stigma
during experiments. Inspite of synchronous nature of anther dehiscence and stigmatic receptivity, selfing in a flower was
avoided due to herkogamy. Some selfing, however, occurred through geitonogamous mode as bagging of panicles yielded 12.21 ± 0.99
to 14.12 ± 0.91% fruit set. High pollen ovule ratio (9,250–10,600) indicated toward the obligate outbreeding nature. The species
suited to insect and wind mode of pollination. High amount of air borne pollen grains deposited on glycerine smeared glass
microscopic slides suggested towards the wind mode of pollination. Though flowers are dull coloured a variety of insects visited
the flowers due to sweet fragrance and stamen/pollen as food reward. Among insect pollinators, honey bee (Apis dorsata) was the major and legitimate pollinator while the rest were either minor pollinators or mere visitors. Inspite of high fruit/seed
set, natural regeneration through seeds was poor as fallen fruits were destroyed by fungal pathogens and white ants. The species
also propagated vegetatively through coppices and root suckers. It lacks agamospermy as bagging of emasculated flowers yielded
no fruit. It is inferred that ‘bael’ which lacks agamospermy reproduced successfully through gamospermy (xenogamy and geitonogamy)
and vegetative mode (coppices and root suckers). We also concluded that tetraploid trees growing in the Pachmarhi hills with
large sized fruits possessed better potentialities in horticulture if planted through root suckers or coppices. 相似文献
7.
8.
Schreier WJ Schrader TE Koller FO Gilch P Crespo-Hernández CE Swaminathan VN Carell T Zinth W Kohler B 《Science (New York, N.Y.)》2007,315(5812):625-629
Femtosecond time-resolved infrared spectroscopy was used to study the formation of cyclobutane dimers in the all-thymine oligodeoxynucleotide (dT)18 by ultraviolet light at 272 nanometers. The appearance of marker bands in the time-resolved spectra indicates that the dimers are fully formed approximately 1 picosecond after ultraviolet excitation. The ultrafast appearance of this mutagenic photolesion points to an excited-state reaction that is approximately barrierless for bases that are properly oriented at the instant of light absorption. The low quantum yield of this photoreaction is proposed to result from infrequent conformational states in the unexcited polymer, revealing a strong link between conformation before light absorption and photodamage. 相似文献
9.
The present study investigated impact of exogenous application of indole acetic acid (IAA; 10 and 100 μM) in pea seedlings under hexavalent chromium (Cr VI; 50, 100 and 250 μM). Cr and 100 μM IAA alone as well as in combination decreased seed germination rate compared to control. However, under Cr phytotoxicity, addition of 10 μM IAA recovered seed germination rate to the level of control. Exposure of pea seedlings to Cr and 100 μM IAA during their early stage caused decrease in fresh mass, length, protein and nitrogen contents of roots and shoots compared to control. Treatment of pea seedlings with Cr resulted in a rapid accumulation of this metal in roots and shoots. Moreover, addition of 100 μM IAA together with Cr, further increased accumulation of this metal in roots and shoots compared to Cr treatments alone. Treatment of pea seedlings with Cr and 100 μM IAA, resulted in a marked decrease in nitrate reductase, nitrite reductase, glutamine synthetase and glutamate synthase (GOGAT) activities (except 50 μM Cr alone for GOGAT), and an increase in ammonium content and glutamate dehydrogenase activity. Parameters related with oxidative stress, i.e. superoxide radicals and reactive carbonyl groups (protein oxidation) were increased by Cr and 100 μM IAA compared to control. By contrast, addition of 10 μM IAA together with Cr, alleviated negative effect of Cr on growth, protein, nitrogen and nitrogen metabolism, and led to decrease in oxidative injuries caused by Cr. The data indicate that 10 μM IAA protects pea seedlings during the early growth period against Cr phytotoxicity by regulating Cr accumulation and oxidative damage. However, addition of 100 μM IAA together with Cr showed opposite responses. 相似文献
10.
Zhiping Shen Vijay Mishra Brian Imison Martin Palmer Robert Fairclough 《Journal of agricultural and food chemistry》2002,50(1):154-160
Orange oil is composed largely of terpene hydrocarbons but is a source of flavor and fragrance compounds (oxygenated) that are present in low concentrations. To increase the ratio of oxygenated compounds to terpene hydrocarbons, orange oil was partially fractionated by adsorption of the oxygenated compounds onto porous silica gel, with full utilization of its adsorbent capacity, and then further purified by desorption into supercritical carbon dioxide. The desorption of 24 compounds was monitored by GC and GC-MS. Adsorption alone removed three-fourths of the terpene hydrocarbons, and fractional extraction by supercritical carbon dioxide (SC-CO(2)) improved the separation further. Response surface methodology was used in the experimental design, and regression analysis was used to determine the effects of process variables. Extraction at low temperatures and flow rates improved separation by SC-CO(2). Decanal was concentrated to 20 times that of the feed oil by using SC-CO(2) at 13.1 MPa, 35 degrees C, and 2 kg/h. The systems were operating at close to equilibrium conditions because of the fine dispersal of the oils and the excellent mass transfer properties of supercritical carbon dioxide. 相似文献