全文获取类型
收费全文 | 83篇 |
免费 | 4篇 |
专业分类
林业 | 7篇 |
农学 | 7篇 |
基础科学 | 1篇 |
15篇 | |
综合类 | 15篇 |
农作物 | 7篇 |
水产渔业 | 8篇 |
畜牧兽医 | 16篇 |
园艺 | 2篇 |
植物保护 | 9篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 12篇 |
2012年 | 7篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2001年 | 4篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1993年 | 1篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 420 毫秒
1.
Identification of genic SSRs in jute (Corchorus capsularis,Malvaceae) and development of markers for phenylpropanoid biosynthesis genes and regulatory genes 下载免费PDF全文
2.
3.
Song imitation in birds provides good material for studying the basic biology of vocal learning. Techniques were developed for inducing the rapid onset of song imitation in young zebra finches and for tracking trajectories of vocal change over a 7-week period until a match to a model song was achieved. Exposure to a model song induced the prompt generation of repeated structured sounds (prototypes) followed by a slow transition from repetitive to serial delivery of syllables. Tracking this transition revealed two phenomena: (i) Imitations of dissimilar sounds can emerge from successive renditions of the same prototype, and (ii) developmental trajectories for some sounds followed paths of increasing acoustic mismatch until an abrupt correction occurred by period doubling. These dynamics are likely to reflect underlying neural and articulatory constraints on the production and imitation of sounds. 相似文献
4.
V S Panangala T B Haynes R D Schultz A Mitra 《Veterinary immunology and immunopathology》1986,13(1-2):71-84
Immunomodulation with killed Propionibacterium acnes was attempted in guinea pigs simultaneously vaccinated with Brucella abortus strain 19. Two groups, each comprised of 9 guinea pigs, were injected by different routes (s.c. and or i.v.) with 1.4 mg of P. acnes and 5 X 10(8) CFU of B. abortus, S-19, while 3 other groups each received either P. acnes, B. abortus S-19, or saline (s.c.). The antibody titers to B. abortus measured at 6, 10 and 14 weeks after vaccination indicated no significant (P less than 0.01) response in the 2 groups immunopotentiated with P. acnes concurrent with B. abortus S-19 vaccination. The delayed hypersensitivity response to 3 Brucella antigens conducted 8 weeks after immunization did not show a significant difference between the B. abortus S-19 vaccinated group compared with the 2 groups immunopotentiated and vaccinated. However, the proliferative response of lymphocytes to the B. abortus soluble antigen diluted 1:100 indicated significantly enhanced blastogenesis in the (s.c.) immunopotentiated and immunized guinea pigs compared with the B. abortus S-19 vaccinated group. A slightly enhanced response was also observed in the group immunopotentiated (i.v.) and vaccinated (s.c.). The guinea pigs were challenged with B. abortus strain 2308 and necropsied 4 weeks later. The mean splenic CFU of the Brucella in the group immunopotentiated (i.v.) and vaccinated (s.c.) was significantly decreased when compared with the guinea pigs vaccinated with B. abortus S-19 alone. These findings indicated that P. acnes administered simultaneously with B. abortus S-19 vaccine was able to augment the immune response in guinea pigs. Immunomodulation as evidenced by enhanced clearance of B. abortus from the spleens of immunopotentiated animals was presumably brought about by activated macrophages or a T-cell mediated cytolytic mechanism or both. 相似文献
5.
H. M. Tuihedur Rahman Jiban Chandra Deb Gordon M. Hickey Imrul Kayes 《Journal of Forest Research》2014,19(1):12-21
This research contrasts the financial profitability of different agroforestry practices in community-based buffer zone management of Madhupur National Park (MNP), Bangladesh. This park is the second largest in Bangladesh and subjected to enormous anthropogenic pressure and land rights-related conflicts. This paper reports the different agroforestry practices of villagers in different modules of the buffer zone of MNP, identified by a participatory research approach. It then assesses the profitability of each module on the basis of cost–benefit analysis, net present value, internal rate of return, and annualized income. Results indicate three agroforestry systems were being practised in the buffer zone by the participants: agro-silviculture, agro-silvo-horticulture, and combined woodlot and agroforestry. Among these modules, agro-silvo-horticulture was the most profitable, followed by agro-silviculture then combined woodlot and agroforestry. We recognize that not all of the participants can practise intensive agroforestry; our results suggest that the community-based buffer zone management strategy for MNP would benefit from prioritizing agroforestry practices where possible. This will lead to more successful buffer zone management for the conservation of natural forests while supporting the development of local resource-dependent communities. 相似文献
6.
A new mannose-binding lectin was purified from plasma of freshwater fish, rohu (Labeo rohita) by ammonium sulphate precipitation followed by DEAE-cellulose ion-exchange chromatography. The hemagglutinating activity
is strong for neuraminidase-treated rabbit erythrocytes. Mannose, glucose and their derivatives inhibit hemagglutination.
The apparent molecular weight was determined to be 210 kDa in native PAGE. Analysed on SDS-PAGE under reducing and non-reducing
conditions, the protein migrated as a single band of mol.wt. 40,000. The lectin is acidic in nature showing a pI of 4.5. It
is a glycoprotein containing complex glycan part as indicated by carbohydrate analysis using high-pressure anion exchange
chromatography with a pulsed amperometric detector. The N-terminal sequence (WLNGIGTQIPMKITT) shows no significant homology
with known proteins. It appears to be a C-type lectin as Ca2+ is essential for carbohydrate-binding activity. Methyl -α- D-mannopyranoside was found to be the most potent inhibitor among
the monosaccharides and disaccharides tested. Purified lectin was found to induce intracellular superoxide production following
opsonization of E. coli by its own macrophages.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Dietary essentiality of ascorbic acid in rohu larvae: Quantification with ascorbic acid enriched zooplankton 总被引:2,自引:0,他引:2
Carp larvae, like any other fish larvae dependon natural food during first few days of theirlife. In nursery conditions, high mortality andslow larval growth are of common occurrence;sub-optimal nutrition might be a possiblereason for such consequences. To improve thesituation the effect of feeding ascorbicacid-enriched live food on survival, growth,tissue biochemical composition includingascorbate level was evaluated in first feeding(3 days old) larvae (av. wt. 2.2 mg) of therohu carp, Labeo rohita (Ham.) for aperiod of 15 days (temp. 28.6 ± 1 °C)under natural photoperiod. The larvae (stockingdensity 10 l–1) were offered enriched andnon-enriched zooplankton ad libitumfollowing a rigid schedule with four feedingregimes, each having 3 replicates. In treatmentT1, non-enriched zooplankton (Moina,Daphnia, Cyclops, Diaptomus) and in T2,T3, T4 ascorbic acid enriched (12 henrichment) zooplankton [@10%, 20% and 30%ascorbyl palmitate (AP) inclusion in diet ofzooplankton] were offered. Highest survival(90%) and growth (9563% live weight gain)could be seen in T3 group and the lowestin T1 (62% survival and 805% live weightgain), thus confirming the dietary essentialityof ascorbic acid for rohu larvae. Therequirement has been shown to be 1409 µg/gdry diet. Whole body tissue analyses for crudeprotein, total lipid and RNA: DNA ratiofollowed the same trend as that of growthresponse and percent survival. Significantpositive correlation (r = 0.949 and 0.861) couldbe found with muscle RNA/DNA ratio and muscleRNA content with specific growth rate indifferent treatments. Significant differencewas found in tissue ascorbate levels betweenenriched plankton fed groups, being highest in T3. Such live foodmediated vitamin transfer might be an effectivemeans to provide higher plane of nutrition forhigh survival and rapid growth for rohu larva. 相似文献
8.
Li R Mitra N Gratkowski H Vilaire G Litvinov R Nagasami C Weisel JW Lear JD DeGrado WF Bennett JS 《Science (New York, N.Y.)》2003,300(5620):795-798
Transmembrane helices of integrin alpha and beta subunits have been implicated in the regulation of integrin activity. Two mutations, glycine-708 to asparagine-708 (G708N)and methionine-701 to asparagine-701, in the transmembrane helix of the beta3 subunit enabled integrin alphaIIbbeta3 to constitutively bind soluble fibrinogen. Further characterization of the G708N mutant revealed that it induced alphaIIbbeta3 clustering and constitutive phosphorylation of focal adhesion kinase. This mutation also enhanced the tendency of the transmembrane helix to form homotrimers. These results suggest that homomeric associations involving transmembrane domains provide a driving force for integrin activation. They also suggest a structural basis for the coincidence of integrin activation and clustering. 相似文献
9.
Sundareshwar PV Murtugudde R Srinivasan G Singh S Ramesh KJ Ramesh R Verma SB Agarwal D Baldocchi D Baru CK Baruah KK Chowdhury GR Dadhwal VK Dutt CB Fuentes J Gupta PK Hargrove WW Howard M Jha CS Lal S Michener WK Mitra AP Morris JT Myneni RR Naja M Nemani R Purvaja R Raha S Vanan SK Sharma M Subramaniam A Sukumar R Twilley RR Zimmerman PR 《Science (New York, N.Y.)》2007,316(5822):204-205
10.
Md. Abu Hanif Ranjan Mitra Roy Md. Shafiqul Bari Polash Chandra Ray Md. Shoaibur Rahman Md. Faruq Hasan 《Small-Scale Forestry》2018,17(4):505-522
Agroforestry is one of the most sustainable land management systems practiced around the world due to the socioeconomic benefits that it brings to farmers. In Bangladesh, farmers practice agroforestry, applying indigenous knowledge. The present study was designed to identify the present status, management practices and its role in improving the livelihoods of farmers in northern Bangladesh. Data for the study were collected through quantitative and qualitative methods. A total of 29 tree and 38 agricultural crop species were planted by the102 farmers interviewed. Mangifera indica (relative prevalence 49%) is the most predominant species, followed by Eucalyptus camaldulensis (relative prevalence 35.4%). Farmers of northern Bangladesh plant trees in cropland for fruits (90%), fuel wood (87%) and timber production (79%). Fruit trees were planted with wider spacing while forest and fuel wood species were planted with narrower spacing. Farmer’s livelihoods improved enormously by practicing agroforestry as they have more access to food, fodder and fuel wood which is reflected by greater access to livelihood capitals (except social capital). However, farmers have experienced increased incidences of pests and diseases to the annual crops and trees. Agroforestry practices increases species diversity, ensure economic return and sustain farmer’s livelihoods. 相似文献