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221.
Babesia canis canis is the most frequent causative agent of canine babesiosis in Central Europe, frequently causing severe disease. Recently, many new endemic foci of this disease have been reported from European countries. Growing incidence of canine babesiosis was recorded also in Slovakia during the last decade, from first cases in eastern Slovakia ten years ago to recent cases all over the south of the country. We have used nested PCR-RFLP method to study prevalence of B. c. canis in its natural tick vector Dermacentor reticulatus, collected at three geographically isolated lowland areas of southern Slovakia situated in the southeast, southwest, and west of Slovakia, respectively. The highest prevalence of B. c. canis was observed in D. reticulatus from eastern Slovakia (14.7%; n=327), whereas the prevalence in southwest was significantly lower (2.3%; n=1205). Notably, all 874 D. reticulatus ticks collected at Záhorská ní?ina lowland (W Slovakia) were B. c. canis-negative. Recorded differences in Babesia prevalence concurs well with the shift in incidence of clinical cases of canine babesiosis as observed by vet practitioners. Presented results revealed that eastern Slovakia represents an area of high risk of B. c. canis infection, whereas western areas of the country still remain Babesia canis-free. 相似文献
222.
Daalkhaijav Damiran Timothy DelCurto Scott L. Findholt Bruce K. Johnson Martin Vavra 《Strength and Conditioning Journal》2013,66(1):106-109
We conducted a study to compare the bite-count technique (BC) of estimating forage intake and synthesized diet quality to direct estimates of diet quantity and quality with the use of the rumen evacuation technique (RE). We used four rumen-fistulated steers to evaluate both techniques. Four enclosures in a mixed-conifer rangeland were used. Each enclosure contained two 0.25-ha paddocks that were either nonstocked or stocked by cattle to remove 32 ± 4% of standing crop. We recorded bite-count data during foraging bouts for each steer in each paddock, and then evacuated each rumen following each foraging bout during summer (August). Paddocks stocked prior to each 20-min trial had a reduced (P < 0.05) quantity of forage consumed regardless of technique. BC and RE gave similar (P > 0.10) results on diet quantity and digestibility. However, BC-derived estimates were lower (P < 0.05) for crude protein (CP), acid detergent fiber (ADF), ash, and neutral detergent fiber (NDF). In summary, although BC has the advantage of not requiring rumen-fistulated animals, it did not yield comparable results to RE under range conditions with dense and diverse vegetation. Therefore, investigators should calibrate bite-count technique against fistula technique to solve any accuracy problem in their specific experimental conditions whenever possible. 相似文献
223.
Precision Agriculture - Site-specific weed management (SSWM) can provide significant herbicide savings but requires the reliable detection of weed populations. In this work, the effect of sample... 相似文献
224.
Background
During their movements in the wild, wood mice (Apodemus sylvaticus) distribute small objects, such as leaves or twigs, which are often visually conspicuous. Our experiments demonstrate that these marks serve as points of reference during exploration. Way-marking, as we call it, may diminish the likelihood of losing an "interesting" location, perhaps following disturbance by, for example, a predator or conspecific. Way-marks, being readily portable, may be a less confusing method of marking ephemeral sites than scent marks. They may also be a safer option for local navigation insofar as scent marks can easily be detected by a predator. 相似文献225.
Martin Flaj
hans Pavel Kvasni
ka Petr Rb 《Aquaculture (Amsterdam, Netherlands)》1993,110(3-4):243-248
A high incidence of spontaneous triploidy was found in tench broodstock hormonally treated to induce spawning but without positive response. Triploidy was also observed in random samples of fingerlings from four tench lines. Triploidy was evaluated by counting Ag-stained NORs in erythrocyte nuclei and was confirmed in 62.5% of the broodstock and in a range from 0.00% to 34.62% in fingerlings. Discrimination of tench diploids and triploids based on differences in shape and length of pelvic fins was tested in the broodstock and also in stocks of earlier artificially induced triploid tench by means of the above-mentioned cytogenetic approach and shown to be a rapid method with a high accuracy (96.43%). Natural disposition for egg overripening is one of the possible causes of highly frequent spontaneous triploidy in the analyzed samples. Genetic predisposition, i.e. occurrence of a recessive allele responsible for the failure of the 2nd polar body extrusion when homozygous, was hypothesized as another possible cause of spontaneous triploidy, based on analysis of the relationships among the tench lines. 相似文献
226.
Cultured cells from pineal glands of human fetuses release into their media a substance that has antidiuretic and hydroosmotic activities. The ratio of these activities as well as their susceptibility to tryptic digestion, specific oxidative inactivation by tyrosinase, and reductive inactivation by sodium thioglycollate, indicates the presence of a basic peptide, presumably identical with arginine vasotocin. The total amount of this peptide released into the culture media during 38 days of incubation is about ten times greater than the amount contained in nonincubated pineal glands from fetuses of the same age, strongly suggesting that fetal ependymal cells from the pineal gland can synthesize in vitro a peptide similar to arginine vasotocin. 相似文献
227.
Asara et al. (Reports, 13 April 2007, p. 280) reported sequencing of Tyrannosaurus rex proteins and used them to establish the evolutionary relationships between birds and dinosaurs. We argue that the reported T. rex peptides may represent statistical artifacts and call for complete data release to enable experimental and computational verification of their findings. 相似文献
228.
The long-term development of stand characteristics and tree spatial patterns (TSP), their mutual relation, and linkage to site and tree species were studied in the Boubín primeval forest (protected since 1858). Surveys were carried out in 1851, 1961/1964, 1972, 1984/1989, 1996 and 2010 on one to six research plots sized 0.58-1.00 ha. To see how results from these surveys could be generalized, results were also compared with whole-area data sets (46 ha) from 1972 to 2010.The proportion of Abies alba continually decreased, from 20% in 1851 to 2-3% in 2010. This decrease started no later than at the beginning of the 20th century. In contrast, the proportion of Fagus sylvatica slightly increased. The sum of dead and living wood volume was stable during the 159 year period, with deviations of only up to 5%. From 1961/64 to 2010, the number of living trees continually decreased, but the mean-tree volume and volume of dead wood increased. The distribution of dead wood always differed from the distribution of living trees.A random TSP was always most common, which seems to be typical for this type of forest. This was true even when A. alba was gradually forced out from the stand structure. Nevertheless, the pronounced decrease of A. alba found during the 1961/64 survey compared with 1851 was reflected in a tendency towards clustering, as gaps from A. alba dieback gradually closed. In these gaps, competitive pressure was lower, resulting in more clustered distributions. Regular distribution was recorded only rarely. F. sylvatica maintained a random or clustered TSP over long periods, depending on site conditions. On water-affected plots, it had a consistently higher tendency towards clustering. The only step change in TSP occurred due to Hurricane Emma in 2008. Otherwise, the most marked TSP changes over time were found for Picea abies, in which there was a gradual trend from clustered to random, connected with a decreasing number of individuals.The main reason for the decline of A. alba and the decreased number of living trees from 1961/64-2010 was the on-going effect of a high stock of red deer at the turn of the 19th and 20th centuries. The decreasing trend in the number of living trees showed no marked change, even 60 years after the game pressure was strongly reduced. However, the vertical structure became increasingly homogenized due to the long-term absence of severe abiotic and/or biotic disturbances. 相似文献
229.
Gilbert MT Tomsho LP Rendulic S Packard M Drautz DI Sher A Tikhonov A Dalén L Kuznetsova T Kosintsev P Campos PF Higham T Collins MJ Wilson AS Shidlovskiy F Buigues B Ericson PG Germonpré M Götherström A Iacumin P Nikolaev V Nowak-Kemp M Willerslev E Knight JR Irzyk GP Perbost CS Fredrikson KM Harkins TT Sheridan S Miller W Schuster SC 《Science (New York, N.Y.)》2007,317(5846):1927-1930
Although the application of sequencing-by-synthesis techniques to DNA extracted from bones has revolutionized the study of ancient DNA, it has been plagued by large fractions of contaminating environmental DNA. The genetic analyses of hair shafts could be a solution: We present 10 previously unexamined Siberian mammoth (Mammuthus primigenius) mitochondrial genomes, sequenced with up to 48-fold coverage. The observed levels of damage-derived sequencing errors were lower than those observed in previously published frozen bone samples, even though one of the specimens was >50,000 14C years old and another had been stored for 200 years at room temperature. The method therefore sets the stage for molecular-genetic analysis of museum collections. 相似文献
230.
Jiří Skuhrovec Miloslav Zouhar Marie Maňasová Pavel Nový Matěj Božik 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(6):489-495
Purpose: Plant-derived essential oils and their encapsulations have recently received increasing interest as an alternative to synthetic biopesticides suitable for integrated pest management and organic farming. In this study, combinations of essential oils (EO) from Rosmarinus officinalis with Cymbopogon citratus and Pelargonium graveolens with Thymus vulgaris in two formulations including encapsulate were tested for their potential for wheat protection against adults and larvae of Oulema melanopus (L.).Materials and methods: The chemical composition of the essential oils was analyzed by gas chromatography-mass spectrometry (GC-MS). Testing of insecticidal activity of the evaluated substances was conducted with 2.5?ml of tested combinations of EOs sprayed on the paper. Ten adults or larvae of O. melanopus were placed into a vessel. Control of mortality of O. melanopus specimens was assessed after 24?h after establishment of the experiment.Results and conclusions: Tarsal contact toxicity assay showed the effectiveness of EO in concentration against O. melanopus larvae and adults in both formulations (essential oil and encapsulation) causing 100% mortality within 24?h. These results indicate the great potential of these essential oils and their encapsulations for future use in crop protection against insect pests. 相似文献