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451.
Effects of Cd, Pb, and Ni on three freshwater green algae, Ankistrodesmus falcatus, Scenedesmus obliquus, and Chlorococcum spp., were studied. Cadmium and Pb had slight stimulatory effects on growth at lower concentrations (0.1 to 1.0 ppm) while they were lethal at higher concentrations (> 5 ppm). Nickel was not lethal between 0.1 and 10.0 ppm. When combined, both Cd and Ni and Cd and Pb showed interaction on A. falcatus. No interaction was noted between Pb and Ni. 相似文献
452.
Ravi Kumar asthana Pramod Kumar Pandey Sureshwar Prasad Ingh 《Water, air, and soil pollution》1990,52(3-4):263-276
Ni inhibited photoautotrophic growth, nitrogenase activity, oxygenic photosynthesis (O2-evolution, 14CO2-uptake) and respiratory O2-uptake in the diazotrophic cyanobacterium, Nostoc muscorum. 14CO2-uptake was more sensitive to Ni compared to nitrogenase activity, O2evolution or respiratory O2-uptake. Lower Ni concentrations (1 μ.M and 5 μM) stimulated N2ase as well as RuBPcase (ribulose bisphosphate carboxylase) activity. It is proposed that Ni inhibition is mainly through the regulation of RuBPcase activity in the cyanobacterium. 相似文献
453.
Twelve profiles representing the principal soils of five major agricultural areas (Al-Kharj, Gassim, Hofuf, Taif and Wadi Dawasir) in Saudi Arabia were described and sampled by horizons. Laboratory analyses were then made of the samples to characterize the profiles more completely. Analyses were also made for certain nutrient elements to get some measure of their levels in the soils.The profiles are tentatively classified in the Entisol and Aridisol orders of the American taxonomy. Five Entisol profiles were considered to be Fluvents and two Psamments. Four Aridisol profiles were considered to be Argids and one an Orthid.All of the profiles are saline and calcareous and most are also sandy. Furthermore, amounts of nutrient elements such as phosphorus, iron and zinc in surface layers are below minimum levels established for similar soils in earlier investigations in other countries. Consequently, the soils are believed to lack sufficient quantities of several elements for optimum plant growth. Successful use of the soils will thus require reductions in salinity, increased levels of nutrient elements, and skillful irrigation to provide adequate moisture. 相似文献
454.
A salinity-tolerant strains of Rhizohium able to grow and fix nitrogen in symbiosis with lentil (Lens esculenta) in saline soil was derived frorn effective Rhizobium strain RL 5. A forced mutation with the mutagen nitrosoguanidine resulted in the isolation of five different mutant strains. The salinity tolerance, streptomycin resistance, growth, nodulation behaviour and relative efficiency of symbiotic N2-fixation of these strains were studied. Among the five mutants and parent, LM 4 and LM 1 successfully tolerated 200 μ g ml?1 streptomycin and 1.5%NaCl. These two mutants also significantly increased number and dry weight of nodules per plant, dry matter yield of the crop and N2-fixation. Between the two, LM 4 seemed generally the better. 相似文献
455.
Chumki Bhattacharjee Nagenahalli Huchappa Manjunath Doddananjappa Theertha Prasad 《Journal of Crop Science and Biotechnology》2009,12(4):253-260
Proteinase inhibitors play a significant role in plant defense against insect pests and phytopathogens by inhibiting their
proteases. A thermotolerant monomeric trypsin inhibitor with molecular weight ∼18kD was purified from Cocculus hirsutus (ChTI) using trypsin sepharose affinity column. Western blot analysis using ChTI IgY revealed its presence in vegetative
parts and seeds. The second and third instar larvae of H. armigera fed with ChTI (5000TIU/ml) resulted in 84.59 and 58.71% reduction in mean larval weight respectively. An increase in the
larval growth period was observed in ChTI fed larvae at all instars and inhibitor fed larvae could not complete their life
cycle. ChTI caused 74 and 59.53% inhibition of bovine trypsin and Helicoverpa gut proteases respectively. ChTI exhibited strain specificity and inhibited growth and development of plant fungal pathogens.
Bioassay studies on yeast strains indicated that ΔYNK and MNN1 are more sensitive to ChTI. The results suggest that phosphodiester
linkage in cell wall components is likely to be the key determinants for binding of ChTI. Taken together, these studies indicate
that ChTI is a potential candidate for development of transgenic plants against foliar diseases and insect pests. 相似文献
456.
457.
Alpana Anupam Jahangir Imam Syed Mohammad Quatadah Anantha Siddaiah Shankar Prasad Das Mukund Variar Nimai Prasad Mandal 《水稻科学》2017,24(1):10-20
We genotyped 74 rice germplasms including Tripura's local landraces, improved varieties, cultivars and breeding lines and other rice varieties using molecular markers for genetic diversity, drought QTLs, and blast resistance genes. The number of alleles per locus ranged from 2 to 5 with an average of 2.9. The polymorphic information content value per locus ranged from 0.059 (RM537) to 0.755 (RM252) with an average of 0.475. Cluster analysis based on 30 simple sequence repeat markers revealed 5 clusters and also indicated the presence of variability within the rice accessions. The drought QTL qDTY2.1 was found in 56.0% of germplasms and qDTY1.1 was detected in only 6.8% of the germplasms. Out of seven rice blast resistance genes screened, only two rice varieties, RCPL-1-82 and Buh Vubuk (Lubuk), were positive for four blast resistance genes while only Releng possessed two blast resistance genes. Among 74 rice germplasms, only three accessions, Releng, RCPL1-82 and Buh Vubuk (Lubuk), possessed both drought-related QTLs and blast resistance genes. Overall, the 74 indigenous rice genotypes showed low level of genetic diversity, which is in contrast to high level of genetic diversity among rice varieties in northeast India, where highlights the good farming practice, conservation of germplasms and the limitation of molecular markers employed in this study. The presence of both drought related QTLs and blast resistance genes in some of the germplasms can be useful in future breeding programmes. 相似文献
458.
Satyajit Saurabh Dinesh Prasad Ambarish S. Vidyarthi 《Journal of Crop Science and Biotechnology》2017,20(2):81-87
The pointed gourd (Trichosanthes dioica Roxb.) is an important cucurbit reported for its medicinal value, therapeutic potential, and as a popular delicacy (especially in Indian cuisine). Being nutritive and desirous, it has potential to feed the nations and addresses their nutritional security and economic prosperity. The plant is usually vegetatively propagated and cultivated for fruits during summer and rainy seasons. The limited supply of planting material, limits cultivation and production. The present study was in anticipation for direct organogenesis, callus induction, and somatic embryo formation from leaf and node explants of T. dioica Roxb. In this study, the MS medium supplemented with 0.5 mg/L BA and 0.5 mg/L 2,4-D was found to be most efficient for callus induction, followed by 0.5 mg/L Kn and 0.5 mg/L 2,4-D. The embryogenic callus was developed by sub-culturing of node callus in the same media. The scanning electron microscopic (SEM) analysis revealed the presence of embryogenic cell clusters having globular embryos, which were found irresponsive to develop further. Through direct organogenesis, the node explants have responded to produce true-to-type plants for propagation. It was observed that MS supplemented with 1.0 mg/L BA was efficient for shoot proliferation, and 0.5 mg/L IAA was found more efficient for root development. Notably, the plant remains unexplored in its potential for improvement involving molecular breeding and tissue culture. These results may be effective to produce genetically stable plants on a large scale and aid the genetic improvement of pointed gourds. 相似文献
459.
Rajeev Raghavan G. Prasad Benno Pereira P.H. Anvar Ali L. Sujarittanonta 《水产资源保护:海洋与淡水生态系统》2009,19(1):67-74
- 1. Denison's Barb, Puntius denisonii (Day) is an endemic and endangered cyprinid fish of the Western Ghats biodiversity hotspot in peninsular India, which is the focus of an organized yet undocumented fishery targeting juveniles for the international aquarium trade.
- 2. Research on P. denisonii has been very limited and there has been no systematic effort to assess and monitor their abundance, distribution and populations.
- 3. Anecdotal and circumstantial evidence indicates a highly restricted distribution, low abundance, declining populations, low catch per unit effort and increasing market prices, providing evidence of an impending conservation crisis and the need for urgent management of wild stocks.
- 4. This paper reviews current knowledge, provides results from the authors' field study and suggests priorities for conservation and management actions for P. denisonii in the streams of Kerala.
460.
Field trials were conducted in cabbage (Brassica oleracea var capitata), cauliflower (B oleracea var botrytis) and knol khol (B oleracea gongylodes) crops at two different locations in Karnataka State (India) to optimize the timing of insecticide applications to control the diamondback moth, Plutella xylostella, using sex pheromone traps. Our results indicate that applications of cartap hydrochloride as insecticide during a 12–24 h period after the pheromone traps had caught on average 8, 12 and 16 males per trap per night in cabbage, cauliflower and knol khol, respectively, were significantly more effective than regular insecticide sprays at 7, 9, 12 or 15 days after transplantation. This was demonstrated by estimation of the mean number of eggs and larvae per plant, the percentage of holes produced, as well as the marketable yield of the three crops at each location. A good correlation between the immature stages, infestation level, the estimated crop yield and the number of moths caught in pheromone traps was also found, indicating the usefulness of pheromone‐based monitoring traps to predict population densities of the pest. © 2001 Society of Chemical Industry 相似文献