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91.
Eucalypt growth in monoculture and silvopastoral systems with varied tree initial densities and spatial arrangements 总被引:1,自引:1,他引:0
Ranieri R. Paula Geraldo G. Reis Maria G. F. Reis Sílvio N. Oliveira Neto Helio G. Leite Raul C. N. Melido Hortênsia N. S. Lopes Felippe C. Souza 《Agroforestry Systems》2013,87(6):1295-1307
Brazil has large stretches of degraded land, mainly occupied by pasture. Recently, the Brazilian government created a program providing financial support to recover these lands throughout the country by establishing agroforestry systems, among others. To select the most appropriate initial spatial arrangements and tree planting density for such systems, the plant growth and leaf area index (LAI) of a Eucalyptus camaldulensis clone were evaluated in five spatial arrangements: 3.6 × 2.5 m, and 3.3 × 3.3 m (monoculture), and (2 × 2) + 10 m, (3 × 3) + 9 m, and 9 × 3 m (silvopastoral systems), with 1,111, 918, 833, 556 and 370 plants per hectare, respectively. The arrangement did not affect plant height growth (p > 0.05) up to 50 months. The average diameter was affected by plant proximity in the planting line, being smaller (p < 0.05) in the arrangements (2 × 2) + 10 m, and 3.6 × 2.5 m, and by the number of lines in the rows, as the plants in the single line arrangement (9 × 3 m) attained the highest diameter. Individual volumes of high initial density stand were lower than in the silvopastoral systems. The arrangements (2 × 2) + 10 m, 3.6 × 2.5 m, and 3.3 × 3.3 m did not differ (p > 0.05) in volume per hectare, which was higher (p < 0.05) than for the other arrangements studied. LAI decreased with age and it was higher (p < 0.01) in the monoculture as compared to the silvopastoral systems. The silvopastoral system can be established in the (2 × 2) + 10 m arrangement for high biomass production besides having the additional benefit of financial returns from the pasture, as compared with the monoculture. The 9 × 3 m arrangement is preferable for large diameter log production. 相似文献
92.
Adriana Schultz Moreira Laura González-Torres Raul Olivero-David Sara Bastida Juana Benedi Francisco J. Sánchez-Muniz 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(3):290-298
The effects of diets including restructured meats (RM) containing Wakame or Nori on total liver glutathione status, and several
antioxidant enzyme gene expressions and activities were tested. Six groups of ten male growing Wistar rats each were fed a
mix of 85% AIN-93 M diet and 15% freeze-dried RM for 35 days. The control group (C) consumed control RM, the Wakame (W) and
the Nori (N) groups, RM with 5% Wakame and 5% Nori, respectively. Animals on added cholesterol diets (CC, CW, and CN) consumed
their corresponding basal diets added with cholesterol (2%) and cholic acid (0.4%). Alga and dietary cholesterol significantly
interact (P < 0.002) influencing all enzyme expressions but not activities. The cholesterol supplement decreased most enzyme expression
and activity. W-RM vs. C-RM increased (P < 0.05) expression of GPx, GR, Mn-SOD, and Cu,Zn-SOD and decreased that of catalase. N-RM vs. C-RM increased (P < 0.05) expression of catalase and Mn-SOD. GR activity increased in W-RM rats while SOD activity increased, but that of Se-GPx
decreased in N animals. W-RM increased total and reduced glutathione and decreased the redox index. CN diet induced significantly
lower plasma cholesterol levels (P < 0.001) than the CW diet. In conclusion, Nori-RM is a hypocholesterolemic food while Wakame-RM is an antioxidant food. This
should be taken into account when including this kind of RM as potential functional foods in human. 相似文献
93.
This paper addresses the issue of automatic wood defect classification. A tree-structure support vector machine (SVM) is proposed
to classify four types of wood knots by using images captured from lumber boards. Simple and effective features are proposed
and extracted by partitioning the knot images into three distinct areas, followed by utilizing a novel order statistic filter
to yield an average pseudo color feature in each area. Excellent results have been obtained for the proposed SVM classifier
that is trained by 800 wood knot images. Performance evaluation has shown that the proposed SVM classifier resulted in an
average classification rate of 96.5% and false alarm rate of 2.25% over 400 test knot images. Future work will include more
extensive tests on large data set and the extension of knot types. 相似文献
94.
95.
Survival,male morphotypes,female and male proportion,female reproductive status and tag loss in crosses among three populations of freshwater prawn Macrobrachium rosenbergii (de Man) in India 下载免费PDF全文
Bindu R Pillai Kanta D Mahapatra Raul W Ponzoni Lopamudra Sahoo P L Lalrinsanga Wagdy Mekkawy Hooi Ling Khaw Nguyen H Nguyen Swagathika Mohanty Sovan Sahu Gunamaya Patra 《Aquaculture Research》2015,46(11):2644-2655
The present study examined the variation in survival, proportion of male morphotypes, female and male proportion, female reproductive status and tag losses in nine crosses from a complete (3 × 3) diallel mating of three populations of Macrobrachium rosenbergii in India. The populations originated from Gujarat (north‐west), Kerala (south‐west) and Odisha (east), representing different agro‐ecological regions in India. Progeny from 60 families (4773 juveniles) were individually tagged and reared for 16–17 weeks in earthen ponds. Binary logistic regression was used to analyse the data. Survival rate was greatest (0.88) for Kerala × Odisha (KO; the first letter represents the sire), whereas it was lowest (0.75) for both Kerala × Kerala (KK) and Gujarat × Kerala (GK). Significantly greater proportions of large male morphotypes were observed in KK cross and in combinations involving Kerala population. The highest proportion of immature females, as well as of non‐berried females, was observed in the Odisha × Odisha (OO) cross. Tag loss was greatest for KK (0.35) and lowest for GG (0.19). We found significant variations among crosses for all studied traits suggesting the possibility of including them in genetic improvement programmes of this species. 相似文献
96.
Leaf‐cutting ants are generally recognized as important pest species in Neotropical America. They are eusocial insects that exhibit social organization, foraging, fungus‐cultivation, hygiene and a complex nest structure, which render their management notoriously difficult. A lack of economic thresholds and sampling plans focused on the main pest species preclude the management of leaf‐cutting ants; such management would facilitate their control and lessen insecticide overuse, particularly the use of insecticidal baits. Recent restrictions on the use of synthetic compounds for such purposes impose additional challenges for the management of leaf‐cutting ants. Considerable effort has been exerted regarding these challenges, which are addressed herein, but which also remain challenges that are yet to be conquered. © 2013 Society of Chemical Industry 相似文献
97.
98.
Diogo Alagador Maria Trivi?o Jorge Orestes Cerdeira Raul Brás Mar Cabeza Miguel Bastos Araújo 《Landscape Ecology》2012,27(2):291-301
Habitat fragmentation is one of the greatest threats to biodiversity. To minimise the effect of fragmentation on biodiversity,
connectivity between otherwise isolated habitats should be promoted. However, the identification of linkages favouring connectivity
is not trivial. Firstly, they compete with other land uses, so they need to be cost-efficient. Secondly, linkages for one
species might be barriers for others, so they should effectively account for distinct mobility requirements. Thirdly, detailed
information on the auto-ecology of most of the species is lacking, so linkages need being defined based on surrogates. In
order to address these challenges we develop a framework that (a) identifies environmentally-similar habitats; (b) identifies
environmental barriers (i.e., regions with a very distinct environment from the areas to be linked), and; (c) determines cost-efficient
linkages between environmentally-similar habitats, free from environmental barriers. The assumption is that species with similar
ecological requirements occupy the same environments, so environmental similarity provides a rationale for the identification
of the areas that need to be linked. A variant of the classical minimum Steiner tree problem in graphs is used to address
c). We present a heuristic for this problem that is capable of handling large datasets. To illustrate the framework we identify
linkages between environmentally-similar protected areas in the Iberian Peninsula. The Natura 2000 network is used as a positive
‘attractor’ of links while the human footprint is used as ‘repellent’ of links. We compare the outcomes of our approach with
cost-efficient networks linking protected areas that disregard the effect of environmental barriers. As expected, the latter
achieved a smaller area covered with linkages, but with barriers that can significantly reduce the permeability of the landscape
for the dispersal of some species. 相似文献
99.
Diego A. Bolívar-Silva Nelsa Maria P. Guedes Raul Narciso C. Guedes 《Journal of pest science》2018,91(2):707-716
Resource limitation is an important determinant of life history and behavior while mediating competition and reproduction among organisms. Discreet and closed systems such as grain kernels and seeds impose drastic restrictions to grain beetles that spend their immature stages within a single kernel selected by their mother. This is the case of internally feeding stored grain beetles, such as the grain weevils. Female egg-laying decisions and larval competition largely determine resource limitation for such insects where clustered egg distribution and contest competition with larval interference and cannibalism take place. As the clustered eggs within a grain lead to larval competition and conspecific weevil larvae face each other off during development allowing the emergence of one or two larvae per kernel, we hypothesized that such competition and consequent cannibalism will have fitness consequences for the competing individuals and their offspring. Thus, larvae of the granary weevil (Sitophilus granarius L.) and the maize weevil (Sitophilus zeamais Motsch.) were subjected to larval competition with cannibalism, and lack of it, to assess the potential fitness consequence of cannibalism on these non-carnivorous pest species of stored grains. Larval cannibalism reduced developmental time of maize weevil, but not of granary weevil. However, such condition led to heavier adult weevils of both species exhibiting higher reproductive output generating more and better quality progeny than non-cannibal weevils. These findings indicate direct nutritional benefits of cannibalism to grain weevils favoring their status of key pest species of stored cereal grains. 相似文献
100.