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991.
Broccoli (Brassica oleracea L. var. ‘Italica’) is a recognized health-promoting vegetable and shows a moderate sensitivity to salinity. As very little is known about the effect of salt stress on broccoli plants, the objective was to evaluate nitrogen (N), phosphorous (P), and sulfur (S) nutrition in plants grown under saline conditions. For this objective, the contents of nitrate, phosphate, and sulfate, and total nitrogen, phosphorus, and sulfur, as well as related metabolic enzymes, were determined for plants grown with 0, 20, 40, 60, 80, or 100 mM sodium chloride (NaCl) for two weeks. Nitrate, phosphate, and sulfate concentration in leaves and roots showed a maximum at 40–60 mM NaCl. Up to these salt levels, broccoli plants showed a normal development, but over these salt levels, broccoli plants showed a decrease of nitrate reductase and an increase of the acid phosphatase. From 60 to 100 mM NaCl, the nutritional disorders indicated that the threshold of resistance was exceeded.  相似文献   
992.
Experiments suggest that biodiversity enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools (multifunctionality). However, the relationship between biodiversity and multifunctionality has never been assessed globally in natural ecosystems. We report here on a global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth's land surface and support over 38% of the human population. Multifunctionality was positively and significantly related to species richness. The best-fitting models accounted for over 55% of the variation in multifunctionality and always included species richness as a predictor variable. Our results suggest that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in drylands.  相似文献   
993.
During development of the mammalian cerebral cortex, radial glial cells (RGCs) generate layer-specific subtypes of excitatory neurons in a defined temporal sequence, in which lower-layer neurons are formed before upper-layer neurons. It has been proposed that neuronal subtype fate is determined by birthdate through progressive restriction of the neurogenic potential of a common RGC progenitor. Here, we demonstrate that the murine cerebral cortex contains RGC sublineages with distinct fate potentials. Using in vivo genetic fate mapping and in vitro clonal analysis, we identified an RGC lineage that is intrinsically specified to generate only upper-layer neurons, independently of niche and birthdate. Because upper cortical layers were expanded during primate evolution, amplification of this RGC pool may have facilitated human brain evolution.  相似文献   
994.
Recent findings on the molecular damage occurring in the stallion spermatozoa are reviewed. Mechanisms leading to cell death or survival are briefly overviewed, and recent discoveries on molecular pathways leading to sperm death and sublethal damage are discussed. Increasing the understanding of this particular area may disclose clues to develop new strategies to improve current sperm conservation methods.  相似文献   
995.
996.
The economic importance of sheep production is increasing worldwide simultaneously with the emergence of parasitic resistance. This study aimed to survey the current situation of management practices and parasite resistance in sheep flocks in S?o Paulo state, Brazil. A questionnaire was given to 35 sheep farmers to obtain information related to flock management practices. Of these flocks, 30 were submitted to the fecal egg count reduction test (FECRT) with at least one of the five following anthelmintics: albendazole, closantel, ivermectin, levamisole, and moxidectin, for comparison against an untreated control group. In the survey, the median number animals per flock was 301, mainly of the Santa Ines breed (in 75.8% of the flocks) and crossbred animals (in 54.5% of the flocks). The predominant farming system was semi-intensive (82.9%), using rotational grazing (80%). Selective treatment was based on FAMACHA grade (47.1%) and in clinical signs (41.2%). The most often applied anthelmintics were macrocyclic lactones (42.9-54.2% in the last three applications). Considering the anthelmintics employed in this study, 10.7% of the farms' flocks were resistant to three, 35.7% to four, and 53.6% to all five anthelmintics. The main helminth genera observed before and after treatments were Haemonchus sp. (75.8%) and Trichostrongylus sp. (19.1%), but all observed genera (Cooperia sp., Oesophagostomum sp., and Strongyloides sp.) were detected by the FECRT. Considering efficacy values less than or equal to 90% in the FECRT as resistant, 100% of flocks were resistant to albendazole and ivermectin, 96.6% to moxidectin, 92.9% to closantel, and 53.6% to levamisole. It is thus possible to conclude that multidrug resistance is widespread in sheep flocks in S?o Paulo state, Brazil, and this involves all prevalent helminth genera.  相似文献   
997.
Caulerpin (1a), a bis-indole alkaloid from the marine algal Caulerpa sp., was synthesized in three reaction steps with an overall yield of 11%. The caulerpin analogues (1b–1g) were prepared using the same synthetic pathway with overall yields between 3% and 8%. The key reaction involved a radical oxidative aromatic substitution involving xanthate (3) and 3-formylindole compounds (4a–4g). All bis-indole compounds synthesized were evaluated against the Mycobacterium tuberculosis strain H37Rv, and 1a was found to display excellent activity (IC50 0.24 µM).  相似文献   
998.
This study reports the occurrence of Toxoplasma gondii in the brain of three striped dolphins (Stenella ceoruleoalba) found stranded on the Ligurian Sea coast of Italy between 2007 and 2008. These animals showed a severe, subacute to chronic, non-purulent, multifocal meningo-encephalitis, with the cerebral parenchyma of two dolphins harbouring protozoan cysts and zoites immunohistochemically linked to T. gondii. Molecular, phylogenetic and mutation scanning analyses showed the occurrence of Type II and of an atypical Type II T. gondii isolates in one and two dolphins, respectively. In spite of the different molecular patterns characterizing the above T. gondii genotypes, the brain lesions observed in the three animals showed common microscopic features, with no remarkable differences among them. The role of T. gondii in causing the meningo-encephalitis is herein discussed.  相似文献   
999.
Asian citrus psyllid, Diaphorina citri (Kuwayama), preferentially orient toward citrus hosts infected with the phytopathogenic bacterium, Candidatus liberibacter asiaticus (CLas) the agent of citrus greening (Huanglongbing, HLB), compared to uninfected counterparts. We investigated whether this preference for the odors of infected plants could be useful for the development of an attract-and-kill (AK) device for D. citri. Twenty-nine blends of volatile organic compounds derived from the odor of citrus infected with CLas were tested in laboratory olfactometer tests, and two blends were also assessed under field conditions. A seven component blend of tricosane: geranial: methyl salicylate: geranyl acetone: linalool: phenylacetaldehyde: (E)-β-ocimene in a 0.40: 0.06: 0.08: 0.29: 0.08: 0.06: 0.03 ratio released from a proprietary slow-release matrix attracted twice more D. citri to yellow sticky traps compared with blank control traps. The attractive blend was subsequently co-formulated with spinosad insecticide into a slow-release matrix to create a prototype AK formulation against D. citri. This formulation effectively reduced the population density of D. citri up to 84% as measured with tap counts when deployed at a density of eight 2.5 g dollops per tree as compared with untreated controls in small plot field trials conducted in citrus orchards. Psyllid populations were not statistically affected at a deployment rate of four dollops per tree. Our results indicate that an AK formulation incorporating spinosad and a volatile blend signature of citrus greening into a slow-release matrix may be useful to suppress D. citri populations.  相似文献   
1000.
In all, 72 samples of raw materials for equine feed were collected from farms located in different parts of northern Italy, and the presence of deoxynivalenol (DON) and T-2 toxin was evaluated using enzyme-linked immunosorbent assay. DON was detected in 38.9% of the samples tested, at levels ranging from 0.2 to 1.9 mg/kg. Maize was found to have the highest concentrations of DON, whereas barley was found to be the most commonly contaminated grain (73.3%). T-2 toxin was found in maize and rice bran at levels ranging from 12 to 102 μg/kg, with an overall incidence of 12.3% in the samples analyzed. In almost all the samples, T-2 toxin was found only in combination with DON. The occurrence of contamination observed in this survey, especially the presence of DON, is noteworthy. The levels detected are not very high, but even long-term exposure to low doses of these mycotoxins may represent a threat to horse health.  相似文献   
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