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341.
Journal of Pest Science - Silicon (Si) accumulation in plants is widely recognised as an effective physical defence against chewing herbivores. However, its effects on some feeding guilds such as... 相似文献
342.
Arsenic mobility and groundwater extraction in Bangladesh 总被引:13,自引:0,他引:13
Harvey CF Swartz CH Badruzzaman AB Keon-Blute N Yu W Ali MA Jay J Beckie R Niedan V Brabander D Oates PM Ashfaque KN Islam S Hemond HF Ahmed MF 《Science (New York, N.Y.)》2002,298(5598):1602-1606
High levels of arsenic in well water are causing widespread poisoning in Bangladesh. In a typical aquifer in southern Bangladesh, chemical data imply that arsenic mobilization is associated with recent inflow of carbon. High concentrations of radiocarbon-young methane indicate that young carbon has driven recent biogeochemical processes, and irrigation pumping is sufficient to have drawn water to the depth where dissolved arsenic is at a maximum. The results of field injection of molasses, nitrate, and low-arsenic water show that organic carbon or its degradation products may quickly mobilize arsenic, oxidants may lower arsenic concentrations, and sorption of arsenic is limited by saturation of aquifer materials. 相似文献
343.
Jahirul Islam Lukmanur Rahman Bhuiyan Abdul Ghani 《Irrigation and Drainage Systems》1991,5(4):351-362
The study was conducted in Monsoon (Transplanted Aman) at BRRI farm, Joydebpur, from 1978–1987, to determine the impact and viability of supplemental irrigation. The results of 8 years of experimentation indicate that the impact of supplemental irrigation mainly depends on rainfall distribution patterns and the last precipitation of the season. Generally, the late transplanted crops suffer from moisture stress when the last rainfall ceases by the first week of October. Under this situation, one timely supplemental irrigation of 60 mm could produce about 58% more yield, and the consequent benefit cost ratio of supplemental irrigation would be 5.3 to 14.5, which is highly profitable. The study reveals that if the last rainfall continues up to the third week of October, the supplemental irrigation is still profitable. When sufficient rainfall occurs in November, there is no need for supplemental irrigation, even in late transplanting, and continuous standing water is not required for rice cultivation provided the rain water can be managed properly.Abbreviations BADC
Bangladesh Agriculture Development Corporation
- B/C Ratio
Benefit Cost Ratio
- BRRI
Bangladesh Rice Research Institute
- HYV
High Yielding Variety 相似文献
344.
Md. Ahasanul Hoque Mohammad Mahmudul Hassan Enamul Haque Amir Hossan Shaikat Shahneaz Ali Khan Abdul Alim Lee Francis Skerratt Ariful Islam Hein Min Tun Ravi Dissanayake Tapan Kumar Day Nitish Chandra Debnath Mat Yamage 《Preventive veterinary medicine》2014
A survey of gastrointestinal parasitic infection as determined by faecal examination was conducted among domestic and wild birds in Bangladesh. Birds were sampled from households, wet markets and wetlands in Chittagong and Greater Sylhet districts during April 2012 to February 2013. Mist nets were used to catch resident wild and migratory birds. The overall prevalence of parasitic infection ranged among locations from 25 to 55% in indigenous domestic ducks (live bird samples = 304), 20% in resident wild birds (environmental faecal samples = 40) and 40% in migratory birds (live bird samples = 35). The prevalence of parasitic infection was significantly higher in indigenous domestic ducks collected during summer (39%) than winter (22%) (p = 0.04). In domestic indigenous ducks and Muscovy ducks, both single and multiple types of parasitic infections were found. However, other domestic birds and wild birds often had a single type of parasitic infection. Ascaridia spp. with an average egg load of 50–900, was commonly detected in faecal samples of domestic and wild birds in this study. Other identified parasites were Capillaria spp. and Heterakis spp. both in domestic and wild birds. Improvement of biosecurity measures for household duck farms through educating and motivating household farmers could help mitigate the effects of parasitic infection on production. 相似文献
345.
A.?MilsteinEmail author M.?S.?Islam M.?A.?Wahab A.?H.?M.?Kamal S.?Dewan 《Aquaculture International》2005,13(6):501-518
Coastal shrimp aquaculture in Bangladesh is mostly practiced in an agricultural unit called a Gher, which is a special type
of agricultural field with elevated surrounding embankments/borders situated by the side of a river that is used to grow rice
in winter and shrimp in summer. Ghers of different sizes are managed in different ways. An on-farm project was carried out
to study the effects of Gher size and their related management practices on water quality, shrimp production and the economic
returns of shrimp farming in the Southwest coastal region of Bangladesh. We present here the results of this project with
respect to water quality as explored through factor analysis, which was applied as a way to understand the nature and extent
of the effects of different variables. For the majority of the variables and factors, one-half to two-thirds of their variability
was explained by changes over time (months), and a further one-quarter to one-third was explained by Gher size and associated
management practices. The alternating dry/monsoon season and water management practices determined long-term and large-scale
(annual) water exchange in the Ghers that mainly affected processes related to live and dead particles suspended in the water
column. Processes related to decomposition and nitrification were more dependent on short-term (days) water circulation in
the Ghers, which is turn was reliant on the time span between the exchanges of water in the Ghers and river. Our results show
that improved management leads to higher natural and shrimp productivity in the smaller Ghers and strongly support the argument
put forward by the policy makers and scientific community in Bangladesh that the smaller the Gher, the better they can be
managed and the better the possibility of increased shrimp survival and production. 相似文献
346.
Summary Application of 200 to 800 mg/l silver nitrate (AgNO3) to the female kakrol or teasle gourd (Momordica dioica Roxb.) plant was effective for inducing hermaphrodite flowers. Pollen grain viability of the hermaphrodite flowers was as high as that of normal male flowers. Crossing among female genotypes of different fruit morphotypes, taking pollen from the induced hermaphrodite flowers, produced fruits and seeds. Sex of hybrids between female and normal male segregated into male and female in equal proportion, while the hybrids from female homo-sexual crosses produced only female plants. This indicated that sex of kakrol is controlled by a single factor; male being heterozygous and the female is homozygous recessive. The possibility to evaluate both parents for fruit characteristics should facilitate breeding. 相似文献
347.
Substituting Ability of Individual Barley Chromosomes for Wheat Chromosomes 1. Substitutions Involving Barley Chromosomes 1, 3 and 6 总被引:1,自引:0,他引:1
In order to determine the genetic relatedness of individual barley chromosomes to wheat chromosomes, ‘Betzes’ barley chromosomes 1, 3 and 6 were substituted for individual ‘Chinese Spring’ wheat chromosomes of homoeologous groups 7, 3 and 6, respectively. The substitution status of these lines has been confirmed using isozyme selective markers, chromosome pairing behaviour in F1 hybrids between the substitution lines and the appropriate double ditelocentric stocks of wheat, and hybridization of cDNA probes to the genomic DNA digests of these substitution lines. Each of the three barley chromosomes provided genetic compensation for the wheat chromosomes they replaced in the substitution plants. From the basis of this compensation with respect to plant vigour and fertility, barley chromosomes 1, 3 and 6 have been designated 7H, 3H and 6H. 相似文献
348.
The mildew reactions of the second generation of doubled haploid (DH) plants, derived from anther culture of crosses among three spring barley lines carrying different Mla mildew resistance alleles and the cv. ‘Pallas’, were analyzed by using a set of three European and one Israeli mildew isolate. The results indicated, (1) a significant level of distortion segregation in favour of resistant DH genotypes, which was possibly due to linkage of mildew resistance genes on chromosome 5 with genes for plant regeneration and (2) various degrees of dominance for the different resistance genes studied as well as the possible action of modifier genes. 相似文献
349.
Nahar Sharmin Hasan Md. Faruk Sikdar Biswanath Islam Md. Asadul 《Journal of Crop Science and Biotechnology》2021,24(5):521-531
Journal of Crop Science and Biotechnology - The present investigation was carried out to investigate the effects of rhizosphere bacteria on growth and rice yields. Also, isolation and... 相似文献
350.
小麦叶片的衰老会导致产量的损失,而叶绿素降解是小麦叶片衰老的明显特征,分析小麦叶绿素降解过程中脱植基反应的相关基因叶绿素酶(TaCLH)和脱镁叶绿素水解酶(TaPPH)在春性小麦叶片衰老过程中的作用,为解析小麦叶绿素降解的分子机制提供参考。以10个春性小麦品种为参试材料,对衰老过程中TaCLH和TaPPH的相对表达量进行测定,结合不同品种在开花后不同时期的相对叶绿素含量(SPAD)、功能绿叶面积(GLAD)和叶绿素荧光参数的变化规律,研究叶片衰老过程中TaCLH和TaPPH与SPAD、GLAD和叶绿素荧光参数的相关关系。结果表明,TaPPH的相对表达量与GLAD、SPAD及叶绿素荧光参数[ETR、Fv/Fm、Y(Ⅱ)]等生理指标之间存在极显著负相关关系,与TaCLH相对表达量存在极显著正相关关系,表明TaPPH在春小麦叶绿素降解过程的脱植基反应中起主要作用。 相似文献