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排序方式: 共有98条查询结果,搜索用时 15 毫秒
1.
Aleš Lebeda Ida Blok 《European journal of plant pathology / European Foundation for Plant Pathology》1990,96(1):51-54
Results are given on the occurrence of sexual compatibility types of seven isolates ofBremia lactucae originating fromLactuca serriola (prickly lettuce). It is concluded that the isolates studied are heterothallic. Both compatibility types (B1 en B2) were determined, but type B2 was prevalent. Sexual recombination ofB. lactucae isolates originating from wild and cultivated lettuce may occur.Samenvatting Zeven isolaten vanBremia lactucae, afkomstig vanLactuca serriola in Tsjechoslowakije, zijn onderzocht op hun sexuele compatibiliteitstype door ze te combineren met Nederlandse fysio's vanB. lactucae, afkomstig van cultuursla (L. sativa), waarvan het compatibiliteitstype (B1 of B2) bekend is. Alle isolaten vanL. serriola bleken heterothallisch te zijn, waarbij type B2 meer werd aangetroffen dan type B1. Sexuele recombinatie vanBremia-isolaten van wildeLactuca-soorten en cultuursla blijkt goed mogelijk te zijn. 相似文献
2.
Aleš Lebeda Michaela Sedlářová James Lynn David A. C. Pink 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(4):431-441
Phenotypic and histological responses of cultivated lettuce (Lactuca sativa) and wild relatives L. saligna, L.␣virosa as well as interspecific crosses derived from L. sativa × L. serriola to two races of Bremia lactucae (CS2, CS9) were investigated. With the exception of L. sativa genotypes, all accessions and hybrids expressed incomplete or complete resistance to both pathogen races, with slight differences at seedling and adult plant stages, respectively. Histological features of the interactions (development of pathogen infection structures and host hypersensitive response to attempted infection) were studied on leaf discs 48 h after inoculation. Interactions with similar phenotypic expression of resistance were characterized by significant variation in rate of development of pathogen infection structures and hypersensitive reactions. Differences found within eight Lactuca spp. accessions and hybrids challenged by two distinct pathogen races are interpreted and discussed. 相似文献
3.
Pavel Šamonil Martin Valtera Stanislav Bek Barbora Šebková Tomáš Vrška Jakub Houška 《European Journal of Forest Research》2011,130(6):1075-1091
Soil variability was assessed in a 74.2-ha area within the Žofínsky prales natural forest. Parameters evaluated for 1765 soil
profiles inside 353 graticule plots were as follows: (1) thickness of organic horizons, (2) thickness and form of mineral
horizons, (3) humus form (HF), (4) soil taxonomic unit (STU) and (5) anomalies. In addition, soil reaction (pHKCl) and oxidizable carbon content (Cox) were measured in the laboratory for 734 samples from the upper mineral (A) and lower mineral (B) horizons. The most frequently
occurring humus form was mor followed by moder, hydromor and peaty T-horizon. Entic Podzols, Dystric Cambisols, Haplic Cambisols,
Albic Podzols, Histic (or Haplic) Gleysols, Endogleyic Stagnosols, Fibric or Hemic or Sapric Histosols and Stagnic Gleysols
were all present at the site despite its homogeneous geological bedrock. Overall coefficient of variance (CV) was lower in
terrestrial soils compared with (semi-)hydromorphic soils. Overall variance decreased in both soil groups with increasing
depth, as did CV differences between the fine (up to 10 m) and the locality scales. The lowest CV values occurred for Cox and pHKCl. The CV values differed between STUs as well. Compared to lower horizons, variograms of upper horizons showed greater autocorrelation
at the intermediate spatial scale (10–320 m)—ranging from 50 to 150 m. Semivariance values, however, reached 70–80% of sill
already at a distance of 10 m. The most significant factor of variability at all studied spatial scales is presumably the
soil disturbance regime, followed by terrain micro-topography and the effect of tree species. 相似文献
4.
Sayyed Mohammad Hadi Alavi Martin Pšenička Tomáš Policar Marek Rodina Jitka Hamáčková Pavel Kozák Otomar Linhart 《Fish physiology and biochemistry》2009,35(4):683-693
Sperm quality of Barbus barbus L. was compared among the three following dietary regimes: Group A, fed 100% commercial diet (Karpico™ containing 33% crude
protein and 6% fat), Group B, fed 78% commercial diet and 22% frozen chironomid (Chironomus plumosus) larvae, and Group C, fed 56% commercial diet and 44% frozen chironomid larvae. Concentrations of polyunsaturated fatty acids
(PUFAs) in Group A, B, and C were 39.1, 42.0, and 44.6, respectively, as a percentage of total fatty acids. Sperm morphology,
volume, concentration and motility, total number of spermatozoa, and osmolality of the seminal plasma were compared during
the spawning season. Dietary regime did not influence sperm volume, concentration, or total number of spermatozoa, osmolality
of seminal plasma, or the percentage of motile sperm, but significantly affected sperm morphology (except for anterior and
posterior parts of the midpiece) and sperm velocity (P < 0.05). Groups B and C showed similar sperm characteristics during the spawning season compared to Group A. Almost all parameters
changed either among or within groups during the spawning season, suggesting differences in terms of the optimal time for
sperm collection. The best time for sperm collection was March for Group A, but April for Groups B and C, when the osmolality
of the seminal plasma measured 289 mOsmol kg−1 and sperm motility was maximal. Spermatogenesis, hydration, and cell decomposition were confirmed as the three major parameters
controlling sperm characteristics during the spawning season. The possible correlation between sperm morphology and motility
requires further study. 相似文献
5.
6.
H. Karimi R. Mansoori Ale Hashem G. Ardalani R. Sadrkhanloo H. Hayatgheibi 《Anatomia, histologia, embryologia》2014,43(6):423-428
The vomeronasal organ (VNO) is a tubular structure in the roof of nasal cavity. The important role of this organ is olfaction of sexual odour. In this study, position, anatomical structure and histology of VNO in Iranian camels (camelus domesticus var. dromedaris persica) were determined. Fourteen healthy male camel heads were collected from an industrial slaughterhouse in Tehran, Iran, for anatomical and histological studies (seven each). The length of VNO and width of dental pad and the number and width of palatine crests were measured. For anatomical studies, the mandible was removed, and maxilla and nasal cavity was cut longitudinally and transversely. For histological studies, the mandible was removed, and first 0.5 cm of initial part of VNO was cut. Then, nasal cavity was cut in some segments with 2 cm thickness. The width of VNO was 3.85 ± 0.31 cm and 1.57 ± 0.18 cm in front and distal parts, respectively. The length of VNO was 15.61 ± 0.59 cm. In histological examinations, VNO was surrounded by J‐shape hyaline cartilage. The lining epithelium of lateral wall of VNO was originated from respiratory epithelium, while it had an olfactory epithelium origin in the medial wall. Lamina propria and tunica submucosa were a cavernous connective tissue with seromucous gland with abundant of serous secretory units. The lumen of VNO opens into nasal cavity. The presence of olfactory epithelium found in our study indicates an important role for VNO in pheromone perception and beginning of sexual behaviour. 相似文献
7.
Steve Peigneur Ale? ?ula Nace Zidar Fiona Chan-Porter Robert Kirby David Madge Janez Ila? Danijel Kikelj Jan Tytgat 《Marine drugs》2014,12(4):2132-2143
Clathrodin is a marine alkaloid and believed to be a modulator of voltage-gated sodium (NaV ) channels. Since there is an urgent need for small molecule NaV channel ligands as novel therapeutics, clathrodin could represent an interesting lead compound. Therefore, clathrodin was reinvestigated for its potency and NaV channel subtype selectivity. Clathrodin and its synthetic analogues were subjected to screening on a broad range of NaV channel isoforms, both in voltage clamp and patch clamp conditions. Even though clathrodin was not found to exert any activity, some analogues were capable of modulating the NaV channels, hereby validating the pyrrole-2-aminoimidazole alkaloid structure as a core structure for future small molecule-based NaV channel modulators. 相似文献
8.
Alex Beharav Dalia Lewinsohn Aleš Lebeda Eviatar Nevo 《Genetic Resources and Crop Evolution》2006,53(3):467-474
A total of 1027 genotypes of wild Lactuca spp. (L. serriola, L. saligna, and L. aculeata), originating from Israel, Jordan, East Turkey, Armenia, Kazakhstan, China, and various other countries in Europe were screened
for resistance to the lettuce downy mildew (Bremia lactucae Regel). The genotypes of L. serriola (N = 962); L. saligna (N = 43); and L. aculeata (N = 22) were tested at the seedling stage with two isolates of B. lactucae (race Bl-21 and Isr-74) isolated from cultivated lettuce in Italy and Israel, respectively. Altogether, the isolates possess
virulence against 17 out of 20 Dm genes/R-factors composing the established differential set of lettuce lines/varieties. They could therefore be used for preliminary
detection of the presence of new resistance factors. A total of 83 and three genotypes of L. serriola and L. saligna, respectively, were resistant to infection by each of the two isolates alone as well as to the infection by a mix of the
two isolates. These genotypes probably carry previously unknown resistance, and therefore could be suitable for exploitation
by breeders and further detailed research. The wild progenitor of lettuce, L. serriola, and related species harbor significant untapped genetic resources for lettuce improvement. 相似文献
9.
Alex Beharav Roi Ben-David Ivana Doležalová Aleš Lebeda 《Genetic Resources and Crop Evolution》2010,57(5):679-686
The wild lettuce, Lactuca aculeata Boiss. et Ky., is closely related and fully interfertile with cultivated lettuce, Lactuca sativa L. Altogether, 155 accessions of this wild species, which is rare conserved within the world’s germplasm collections, were
collected from 12 localities throughout northeastern Israel. Ten of these localities represent different sites across the
Golan Heights, while two, high-density populations were suprisingly found at the Hula Plain (first report of this species
in this region). Lactuca aculeata was recorded at various elevations (222–968 m a.s.l.) and habitats. The taxonomic status of 30 L. aculeata accessions was morphologically validated during ex situ seed regeneration of 31 random accessions representing all 12 localities. Characterization of 12 traits showed that the Israeli
populations of L. aculeata do not exhibit broad morphological variability, but more great levels of variation were obtained for developmental traits.
Relatively little variability was observed in the morphology of cauline leaves or in the distribution of anthocyanin pigmentation
in bracteae. In two cases, L. aculeata plants lacked trichomes in the inflorescence, a typical feature in the majority of plants. These unique collections of wild
lettuce may carry novel sources of genetic variation for a wide range of traits and, thus, should be of interest for careful
evaluation and exploitation in lettuce breeding. 相似文献
10.
Gabriela Barančíková Maria Jarzykiewicz Erika Gömöryová Erika Tobiašová Tadeáš Litavec 《Journal of Soils and Sediments》2018,18(8):2738-2747