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排序方式: 共有172条查询结果,搜索用时 78 毫秒
1.
H. Neubauer L. D. Sprague R. Zacharia H. Tomaso S. Al Dahouk R. Wernery U. Wernery H. C. Scholz 《Zoonoses and public health》2005,52(5):201-205
Burkholderia mallei causes glanders or farcy in solipeds, a disease that must be reported to the OIE (Office International des Epizooties, Paris, France). The number of reported outbreaks has increased steadily during the last decade. Serodiagnosis is hampered by the considerable number of false‐positives and ‐negatives of the internationally prescribed tests. The major problem leading to low sensitivity and specificity of complement fixation test (CFT) and enzyme‐linked immunosorbent assay (ELISA) has been linked to the test antigens currently used, i.e. crude preparations of whole cells. Future perspectives for the development and evaluation of serological test kits using well‐characterized single antigens are discussed in the light of recent molecular research on B. mallei and the closely related saprozoonotic agent B. pseudomallei. 相似文献
2.
The isolation and identification of Yersinia enterocolitica from minced meat on CIN agar medium is still one of the major problems in food microbiology because of the low selectivity of cefsulodin–irgasan–novobiocin (CIN) agar. A total of 198 minced meat samples were collected from commercial establishments (butcher shops and supermarkets) in seven German cities in order to investigate the sensitivity and specificity of three identification techniques suitable for the differentiation of Y. enterocolitica within the rich background flora on CIN agar plates. As expected isolation of Y. enterocolitica from minced meat on CIN agar medium after 72 h enrichment in peptone, sorbitol and bile salts (PSB) broth was difficult because all plates were abundantly covered with numerous ‘typical’Yersinia‐like colonies of bull's eye appearance as well as with atypical colonies. Based on the phenotype of the colonies it was possible to detect colonies showing Yersinia‐like growth on CIN agar in 52 samples (26%). For identification of Y. enterocolitica the API 20E system (bioMerieux, Nürtingen, Germany), the Yersinia identification kit (Merlin, Bornheim‐Hersel, Germany) and a 16S rRNA based PCR assay were compared. Only in one sample (0.5%) a Y. enterocolitica strain was detected by all methods. Of the three identification systems tested for routine laboratory diagnostics the API 20E system was found to be the most suitable tool to identify Y. enterocolitica colonies within the rich background flora from minced meat samples on CIN agar plates. 相似文献
3.
The novel β2‐toxin of Clostridium perfringens has recently been described as the cause of enteric diseases in animals. The biological activity of β2‐toxin is similar to that of the β1‐toxin with a possibly weaker cytotoxic activity. However, the production of β2‐toxin in vitro is not seen in all β2‐toxin‐gene (cpb2)‐positive C. perfringens strains, and to deduce a clinical importance solely from the detection of cpb2 is difficult. Detection of cpb2‐positive C. perfringens from various animal species with and without enteric diseases demonstrates the wide distribution of cpb2 in nature, and the presence of cpb2 gene is therefore not considered a risk by itself. Predisposing factors like low trypsin activity in the intestinal tract, antibiotic and/or antiphlogistic treatment or changes in diet can result in the selection of β2‐toxigenic C. perfringens which may lead to enteritis or enterotoxaemia. 相似文献
4.
Theonella swinhoei is a fairly common inhabitant of reefs throughout the Indian and Pacific Oceans. Metabolomic analyses of samples of T. swinhoei collected in different depths in the Gulf of Aqaba revealed two chemotypes differing in the profiles of the theonellamides they produce, some of which seem to be unknown. Driven by this finding, we examined a sample of T. swinhoei collected more than 40 years ago in the southern part of the Gulf of Aqaba. Large-scale extract of this sample yielded four theonellamides, the known theopalauamide (4), as the major component, and three new metabolites, theonellamide J (1), 5-cis-Apoa-theopalauamide (2), and theonellamide K (3), as the minor components. The planar structure of these complex cyclic glycopeptides was elucidated by combination of 1D and 2D NMR techniques and HRESIMS. The absolute configuration of the amino acids was established by Marfey’s and advanced Marfey’s methods, and the absolute configuration of its galactose unit using “Tanaka’s method” for monosaccharides. The biological activity of the pure compounds was tested for antibacterial activity and for cytotoxicity to HTC-116 cell line. The compounds presented significant cytotoxicity against the HTC-116 cell line, illuminating the importance of the Apoa subunit for the activity. 相似文献
5.
Ninety sexually mature Cherax quadricarinatus females were exposed to various combinations of photoperiod and temperature for 2 months during the summer. Females were randomly assigned to either “winter” “semi-winter” or “summer” simulation treatments. In the “winter” treatment, crayfish were exposed to a simulated winter photoperiod (gradual decrease from 14L:10D to 10L:14D, 4 weeks at short day length followed by gradual increase to 14L:10D) and temperature (gradual decrease from 27 to 15 °C, held for 4 weeks, and then gradual increase to 27 °C). In the “semi-winter” treatment, crayfish were exposed to a simulated winter photoperiod and a summer temperature (27–29 °C). In the “summer” treatment, the crayfish were exposed to summer water temperatures and a photoperiod of 14L:10D. Following the 2 months of conditioning, the females were stocked for 7 months in small groups with males under environmental conditions similar to those of the “summer” treatment. All females were individually tagged and molting and spawning events were monitored. Females exposed to “semi-winter” conditioning in the summer, demonstrated a threefold increase in the rate of first spawning during the winter (December–February) compared with the other females. Crayfish breeders can easily implement these findings since shifting the breeding season into the winter only requires shortening of the photoperiod in the summer. The stocking of ponds in the spring with large nursed juveniles that hatched from eggs spawned in the winter, would allow the attainment of market size at the end of the limited growout season in temperate zones. 相似文献
6.
A nine-year-old, intact female dalmatian with diabetes mellitus and a renal abscess is described. The renal abscess was treated surgically by nephrectomy, and the diabetes mellitus resolved with ovariohysterectomy. Abdominal ultrasound and ultrasound-guided aspiration of the abscess were helpful in establishing a diagnosis. To the authors' knowledge, this is the first report of a renal abscess in a dog with diabetes mellitus. 相似文献
7.
In Europe, Phytophthora ramorum basically infects Rhododendron and Viburnum. To prevent the spread of the new quarantine organism in nurseries more knowledge about the transmission biology of this pathogen is necessary. For this reason the pathways of spread for P. ramorum on the two main host plants have been studied for the first time. Under practical field conditions inoculated plants were placed as sources of infections in a larger stock. Over 3?months the development of infestation was recorded. The pathogen showed a poor potential of spread. At the end of the trial only 1.0% of Rhododendron and 0.3% of Viburnum were infested with P. ramorum. Typical symptoms could be observed. On Rhododendron the pathogen caused a branch dieback. Stems showed a brown discoloration, which starts usually at the tip of the twig and moved towards the base. Infected Viburnum showed a stem base rot with wilting symptoms. Additionally rhododendrons were natural infested with Phytophthora citricola. This pathogen caused the same symptoms like P. ramorum and spread much faster. Investigations of leaf litter showed that both Phytophthora species had colonized the ground. This observation and the pattern of spread indicate that inoculum on the ground has been transmitted to arial plant parts via rainsplash. There is little evidence that P. ramorum has been transmitted directly from plant to plant via splashwater or air. 相似文献
8.
Edna Sharon Ilan Chet Ada Viterbo Meira Bar-Eyal Harel Nagan Gary J. Samuels Yitzhak Spiegel 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):247-258
Trichoderma (T.
asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived
eggs and second-stage juveniles (J2) were parasitized by Trichoderma
asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma
asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without
gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi.
The gelatinous matrix specifically induced J2 immobilization by T.
asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation
of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca2+-dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes.
All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinous-matrix-coated
nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching
and appressoria-like structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated
in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of
Trichoderma isolates and their parasitic capabilities on M. javanica, elucidating the importance of the gelatinous matrix in the fungal parasitism. 相似文献
9.
The optimal conditions required to market Trichoderma as a biocontrol agent against soilborne fungi and nematodes are discussed. These include a proper formulation, an efficient delivery system, and alternative methods for Trichoderma's application.The implementation of Trichoderma in integrated pest management (IPM) can be achieved using a soil treatment which combines reduced amounts of biocides/fungicides and the Trichoderma preparation. Biocontrol activity can be increased by combining two (or more) types of biocontrol agents. Moreover, the construction of a genetically modified Trichoderma can lead to the improvement of certain traits which are absent or not highly expressed in the native microorganism isolated from its natural habitat.Different Trichoderma harzianum and T. lignorum isolates were tested for their nematicidal activity against the root-knot nematode Meloidogyne javanica. In short-term experiments, improved growth of nematode-infected plants and decreases in the root-galling index and the number of eggs per gram of root were achieved when nematode-infested soils were pre- exposed to the T. harzianum preparations. A long-term experiment resulted in improved growth and higher yield of nematode-infected plants, but no significant change in the galling index, either by pre-exposure of the fungus to the soil or by enrichment in the root-ball.As biocontrol is an integral part of the IPM philosophy, judicious use of Trichoderma against soilborne pathogens, when demonstrated to be consistently effective, practical and economic, can serve as a model for the introduction and implementation of other biocontrol means into IPM. 相似文献
10.
Mayada Gwida Maged El-Ashker Falk Melzer Mohamed El-Diasty Mohamed El-Beskawy Heinrich Neubauer 《Irish veterinary journal》2015,69(1):3