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41.
Land-use allocation protects the Peruvian Amazon   总被引:2,自引:0,他引:2  
Disturbance and deforestation have profound ecological and socioeconomic effects on tropical forests, but their diffuse patterns are difficult to detect and quantify at regional scales. We expanded the Carnegie forest damage detection system to show that, between 1999 and 2005, disturbance and deforestation rates throughout the Peruvian Amazon averaged 632 square kilometers per year and 645 square kilometers per year, respectively. However, only 1 to 2% occurred within natural protected areas, indigenous territories contained only 11% of the forest disturbances and 9% of the deforestation, and recent forest concessions effectively protected against clear-cutting. Although the region shows recent increases in disturbance and deforestation rates and leakage into forests surrounding concession areas, land-use policy and remoteness are serving to protect the Peruvian Amazon.  相似文献   
42.
Colletotrichum gloeosporioides is an airborne disease which causes significant yield losses in shallots (A. cepa var. ascalonicum) grown in the tropics. Breeding for resistance to this disease in shallots has been scarcely carried out and has been primarily focussed on Allium cepa material. Wild species related to shallot might provide sources of resistance and therefore a screening of this material was carried out. Three different isolates of C. gloeosporioides originating from Brazil, Nigeria and Indonesia, were used in the screening procedure. The accessions screened of A. cepa and A. oschaninii were most susceptible to the three isolates. Partial resistance was observed in accessions of A. altaicum, A. fistulosum, A. galanthum, A. pskemense and A. roylei. The highest level of resistance was found in accessions of A. galanthum and A. fistulosum. A. roylei was highly resistant to the Brazilian isolate but very susceptible to the Nigerian and Indonesian isolates. A genetic analysis of the resistance present in A. roylei to the Brazilian isolated revealed that it is dominantly inherited and most probably determined by more than one gene. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
43.

This study is aimed at determining the maximum inclusion level of tamarind (Tamarindus indica) residues in the diet of goats on intake, digestibility, ingestive behavior, and nitrogen (N) balance. Twenty-four crossbred (Boer × undefined breed) castrated goat kids (5 months old and with an initial weight of 23.9?±?0.3 kg) were assigned in a completely randomized design (4 treatments and 6 replicates). Diets consisted of Tifton 85 (Cynodon sp.) hay as the roughage (400 g/kg) source and concentrate (600 g/kg); the levels of tamarind residue inclusion were 0.0, 7.0, 14.0, and 21.0% on a dry matter (DM) basis. The experimental period lasted 23 days (15 of adaptation and 8 of sampling). Inclusion of tamarind residue in the goat kid diets did not affect (P?>?0.05) the intake and digestibility of DM, crude protein, neutral detergent fiber (NDF), and total digestible nutrient; intake of N, urinary N, and retained N (g/day); time spent ruminating; numbers of times/day feeding, ruminating, or idling; eating efficiency of DM and NDF; number of boluses/day; and amount (g) of DM/bolus. However, there were a linear reduction in ether extract digestibility (P?=?0.011) and a linear decreasing trend in non-fibrous carbohydrate digestibility (P?=?0.083). The addition of tamarind residue had a positive linear effect (P?=?0.041) on the time spent feeding and promoted a decreasing linear trend for the time spent idling (P?=?0.063). It is recommended to include the residue from tamarind fruit at a level of 21% in diets for goat kids, as it does not affect nutrient intake and digestibility and the N balance.

  相似文献   
44.
This study reports egg production by captive wild brill Scophthalmus rhombus, a potential new flatfish species for Southern Europe‐Mediterranean mariculture, as well as seasonal plasma levels of 17β–estradiol, testosterone, 11–ketotestosterone, proteins, triglycerides, glucose and lactate. A mean egg production of 102 800 eggs kg body weight−1 was achieved during the 2005 spawning period (January–March), although a continuous egg supply could only be obtained from some females, which had a higher relative fecundity (261 019±10 393 eggs kg−1) with 12–17 eggs batches released at a mean interval of 3.4 days. Most eggs were obtained with water temperatures ranging from 12 to 14°C, and under increasing temperatures (up to 2.9°C). Potential egg viability (70.1±2.9%), fertilization (72.2±3.4%) and hatching rates (31.9±3.9%) showed high variability, with potential viability tending to decrease as the water temperature increased (mainly between 16 and 17°C) and 0% hatching above 16.6°C. The endocrine changes that brill underwent during late gametogenesis, spawning and postspawning periods were similar to those reported in other Pleuronectiformes. This study establishes an important basis for further research on the biology and physiology of brill reproduction, directed towards the optimization of the breeding techniques used currently.  相似文献   
45.
46.
An outbreak of necrotic enteritis caused by Clostridium perfringens type C was diagnosed in captive collared (Pecari tajacu) and white-lipped (Tayassu pecari) peccaries housed in the Laboratory of Applied Ethology of Universidade Estadual de Santa Cruz located in Ilhéus, State of Bahia, Brazil. Four collared peccaries and three white-lipped peccaries, all juveniles (25-105 days old), were affected. For all affected animals, lethargy and inappetance were followed by sudden death within 24 hours. Histopathology of intestinal wall, culture of C. perfringens type C, and the identification of beta-toxin from intestinal content confirmed the diagnosis.  相似文献   
47.
Electrochemistry can be a valuable instrument to preserve the aquatic environment, first, by elucidating the oxidation-reduction mechanisms of substances having toxicological potential at laboratory scale; second, by aiding through extrapolation to comprise the evolution and fate in the environment of these pollutants and, finally, by establishing the basis of some electrochemical deactivation processes at industrial scale. In this way, this paper deals on studies of a type of highly pollutant substances for the aquatic media such as the S-triazines. The first part of the paper is focused to show the electrochemical reduction behavior of some S-triazines (eleven compounds have been studied). Later, the probable consequences at natural scale of these electroreductive processes are evaluated. Thus, the electrochemical reduction of diluted solutions of s-triazine herbicides and parent compounds takes place at potentials of ?0.90 to ?1.20 V, at very acidic pH values. The electroreduction products generated in all cases have loss the aromaticity and, depending on the compound, the chlorine atom or the –SCH3 group. So, the resulting molecules present lower toxicity than the original compounds. For this reason, the electroreductive way can be an efficient option for the detoxification of S-triazine polluted waters. On the other hand, the natural deactivation of the s-triazines present in natural waters, in addition to the conventional photooxidative route taking place in well illuminated and oxygenated waters, could take place through the reductive process when the waters are essentially anoxic, acidic, and rich in suspended materials. This natural reduction, moreover, could favour the later oxidation or metabolization of the byproducts emanating of the original plaguicides. Finally, the reduction of S-triazines, both forced (industrial water depuration via electrochemical reduction) and no forced (natural aquatic media) requires more negative redox potentials, that is, more reductive environments as the molecules become more complex.  相似文献   
48.
49.
Sunflower (Helianthus annuus L.) has been rated as moderately salt‐resistant, and variability for salt resistance has been detected within this crop. However, variability in salt‐resistance mechanisms has not been assessed. Osmotic tolerance, the relation of salt resistance with whole‐plant Na+ and K+ distribution and tissue Na+ tolerance were investigated in several sunflower inbred lines. Plants were grown under controlled conditions, in pots with sand and perlite irrigated with salinized (NaCl, –0.65 MPa) nutrient solution. Osmotic tolerance was assessed from the initial effects of the salt treatment on plant elongation in eleven sunflower lines. Long‐term salinity responses were evaluated in four of those lines, by assessing whole‐plant growth. A principal components analysis (PCA) was run on relative‐to‐control growth data, and this information was used to establish a relative resistance ranking, which indicated lines HAR2 > HAR1 > HA64 > HAR5. Osmotic tolerance was observed in HA64 and HAR2. The lines showed different degrees of Na+ accumulation, it was very low in some of them, but relative salt resistance was not associated to this trait. Tissue Na+ tolerance was deduced by comparing the percentage of dead leaves as a function of leaf blade Na+ accumulation, and it was higher in HAR1 than in the rest. These results indicate that variability for salt‐resistance mechanisms exists in sunflower. Osmotic tolerance and tissue Na+ tolerance were detected in different lines, highlighting that such variability may be exploited for increasing salt resistance in this crop.  相似文献   
50.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   
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