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91.
Veneault-Fourrey C Barooah M Egan M Wakley G Talbot NJ 《Science (New York, N.Y.)》2006,312(5773):580-583
Rice blast is caused by the fungus Magnaporthe grisea, which elaborates specialized infection cells called appressoria to penetrate the tough outer cuticle of the rice plant Oryza sativa. We found that the formation of an appressorium required, sequentially, the completion of mitosis, nuclear migration, and death of the conidium (fungal spore) from which the infection originated. Genetic intervention during mitosis prevented both appressorium development and conidium death. Impairment of autophagy, by the targeted mutation of the MgATG8 gene, arrested conidial cell death but rendered the fungus nonpathogenic. Thus, the initiation of rice blast requires autophagic cell death of the conidium. 相似文献
92.
Jenifer R. Gold Tamara L. Grubb Sherry Cox Lais Malavasi Nicholas L. Villarino 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2022,36(2):792
BackgroundThe repeated administration of high doses of gabapentin may provide better analgesia in horses than current clinical protocols.Hypothesis and ObjectivesAdministration of gabapentin at 40 and 120 mg/kg PO q 12 h for 14 days will not alter serum biochemistry findings or cause adverse effects. Our objectives were to evaluate the effect of gabapentin on serum biochemistry, physical examination, and plasma pharmacokinetics of gabapentin.AnimalsSix healthy adult mares.MethodsHorses received 40 and 120 mg/kg of gabapentin orally q 12 h for 14 days. Horses were examined and scored for ataxia and sedation daily. Serum biochemistry variables were analyzed before treatment and days 7 and 14 after gabapentin administration. Plasma disposition of gabapentin was evaluated after the first and last drug administration. Pharmacokinetic parameters were estimated using noncompartmental analysis.ResultsNo changes occurred in physiologic or biochemical variables. Median (range) maximal plasma gabapentin concentrations (μg/mL) after the last dose (day 15) were 7.6 (6.2‐11) and 22 (14‐33) for 40 mg/kg and 120 mg/kg doses respectively. Maximal concentration of gabapentin was reached within 1 hour after drug administration. Repeated administration of gabapentin resulted in a median (range) area under the curve (AUC0‐12 hours) last/first dose ratio of 1.5 (1.00‐2.63) and 2.92 (1.4‐3.8) for the 40 and 120 mg/kg regimens, respectively.Conclusion and Clinical ImportanceOur results suggest that horses tolerate gabapentin up to 120 mg/kg PO q 12 h for 14 days. The analgesic effect of the dosage regimens evaluated in our study warrants further research. 相似文献
93.
David Bruce Lewis Nancy B. Grimm Tamara K. Harms John D. Schade 《Landscape Ecology》2007,22(6):911-924
Nutrient dynamics in rivers affect biogeochemical fluxes from land to oceans and the atmosphere. Fluvial ecosystems are thus
important environments for understanding spatial variability in nutrient concentrations. At the San Pedro River in semi-arid
Arizona, USA, we investigated how variability in dissolved inorganic nitrogen (DIN) was regulated by subsystem type and hydrological
flowpaths. The three subsystems we compared were the riparian zone, parafluvial (gravel bar) zone, and surface stream. DIN
concentration was greater in the riparian zone than in the surface stream, suggesting that the riparian zone retains DIN and
is a source of N for the surface stream. Parafluvial zones were too variable to generalize how they regulate DIN. Our hypothesis
that subsystem type regulates DIN oxidation was too simple. The riparian and parafluvial zones host a mosaic of oxidizing
and reducing conditions, as they exhibited highly variable ammonium to nitrate (NH4+:NO3−) ratios. Surface stream DIN was dominated by NO3−. Along a subsurface flowpath in the riparian zone, we did not observe spatial covariation among the N forms and transformations
involved in mineralization. We also compared spatial variability in solute concentrations between flowpaths and non-flowpath
reference areas. Our mixed results suggest that spatial variability is regulated in part by flowpaths, but also by solute-specific
processing length along a flowpath. To understand the distribution of N in fluvial ecosystems, subsystem type and flowpaths
are readily discernable guides, but they should be coupled with other mechanistic factors such as biota and soil type. 相似文献
94.
95.
Nisha Aravind Mike Sissons Narelle Egan Christopher M. Fellows Jaroslav Blazek Elliot P. Gilbert 《Cereal Chemistry》2012,89(2):84-93
β‐Glucan is known to have valuable properties for preventative health and is finding widespread use in foods. This study investigated the benefit of adding a commercial source of β‐glucan, Barley Balance (BB) flour, as a functional ingredient in spaghetti. Durum wheat semolina was substituted with BB at levels of 7.5, 15, and 20%, from which spaghetti was prepared on a laboratory scale. The substitution of BB increased the β‐glucan content of semolina from 0.3 to 6% in uncooked and 8% in cooked pasta. Antioxidant activity (measured by 2,2‐diphenyl‐1‐picrylhydrazyl) increased with BB and did not decline significantly on processing and cooking. Compared with the control, 7.5% BB had no or minimal effect on pasta cooking loss, stickiness, water absorption, aroma, and sensory texture. However, at higher doses, pasta became less yellow and more brown, firmer, of inferior aroma, more rubbery, and chewy, but less floury to the mouth. The extent of starch digestion decreased with increasing quantities of BB, suggesting that BB may lower glycemic index, with microscopy data suggesting that this decrease was mediated through the development of a more intensive fiber or fiber/protein matrix retarding enzymatic access to starch granules. 相似文献
96.
Galina F. Antonova Tamara N. Varaksina Tatiana V. Zheleznichenko Victoria V. Stasova 《Wood Science and Technology》2014,48(5):919-936
Lignin deposition at consecutive secondary wall thickening stages of early and late xylem cells during annual ring wood formation in Scots pine (Pinus sylvestris L.) stems was studied. Lignin patterns, isolated by thioglycolic acid method, consisted of alcohol-soluble (LTGA-I) and alkali-soluble (LTGA-II) fractions. The sum of two fractions, being the total lignin content, gradually increased in the course of lignification. However, the increments of lignin amount at each development stage of early and late tracheids were different. The intensity of lignin deposition increased in the course of earlywood tracheid maturation and decreased toward the end of latewood cell differentiation. The deposition of two lignin fractions in each layer of forming wood also occurred oppositely. The increment of LTGA-I descended, whereas that of LTGA-II increased from the beginning to the end of early xylem lignification. In contrast, LTGA-I increment dropped, whereas LTGA-II rose during late xylem lignification. Gel permeation chromatography showed that the lignins, formed at the beginning of lignification, were more homogeneous and had higher molecular weight compared with the lignins at the end of cell differentiation. Besides, the content of cellulose, estimated as the residue after lignin isolation, and of cell wall substances, presented as cell wall cross-section areas, at consecutive maturation stages of early and late xylem cells have been found to be different. The data show that lignin deposition occurred in different conditions and with opposite dynamics during early and late xylem formation. 相似文献
97.
Jose Antonio Grande Antonio Jiménez Sixto Romero María Luisa de la Torre Tamara Gómez-Olivera 《Water, air, and soil pollution》2010,212(1-4):299-307
In this work, the determination of moving averages is proposed as a method for quantifying metal, arsenic, and sulfate discharges into a water course undergoing acid mine drainage processes which flows into a public water supply dam in the Iberian Pyrite Belt. The analysis of the results obtained by applying moving averages shows that the highest metal and sulfate concentrations occur in October, coinciding with the first rainfall and the sponging of mine dumps, with November and December being the months when the highest contributions to the Andevalo Dam take place. The discharge of acid mine waters with its corresponding metal load into the Andevalo Dam means, for a single hydrological year, more than 6,000 t of sulfates, almost 600 t of iron, and 1 t of As, of special relevance for the hydrochemical quality of the stored waters. When they arrive at the dam, these metals precipitate, since the water pH is near 7, and remain latent in the bottom sediment as long as the chemical makeup of the dam water does not change. 相似文献
98.
Grubb TL Schlipf JW Riebold TW Cebra CK Poland L Zawadzkas X Mailhot N 《Veterinary anaesthesia and analgesia》2006,33(6):351-355
OBJECTIVE: To determine the minimum alveolar concentration (MAC) of desflurane in llamas and alpacas. DESIGN: Prospective study. Animals Six healthy adult llamas and six healthy adult alpacas. PROCEDURE: Anesthesia was induced with desflurane delivered with oxygen through a mask. An endotracheal tube was inserted, and a port for continuous measurement of end-tidal and inspired desflurane concentrations was placed between the endotracheal tube and the breathing circuit. After equilibration at an end-tidal-to-inspired desflurane concentration ratio >0.90 for 15 minutes, a 50-Hz, 80-mA electrical stimulus was applied to the antebrachium until a response was obtained (i.e. gross purposeful movement) or for up to 1 minute. The vaporizer setting was increased or decreased to effect a 10-20% change in end-tidal desflurane concentration, and equilibration and stimulus were repeated. The MAC was defined as the average of the lowest end-tidal desflurane concentration that prevented a positive response and the highest concentration that allowed a positive response. RESULTS: Mean +/- SD MAC of desflurane was 7.99 +/- 0.58% in llamas and 7.83 +/- 0.51% in alpacas. CONCLUSIONS AND CLINICAL RELEVANCE: The MAC of desflurane in llamas and alpacas was in the range of that reported for other species. 相似文献
99.
Tamara Begdullayeva Kirsten M. Kienzler Elena Kan Nazar Ibragimov John P. A. Lamers 《Irrigation and Drainage Systems》2007,21(3-4):237-250
Water and land salinization, caused by ill-practiced irrigation and drainage is acute and widespread in Karakalpakstan, Uzbekistan.
A crop frequently grown in these marginal areas is sorghum because of its capability to adapt to saline conditions. However,
the salt uptake potential of local varieties for salt-ameliorative purposes, as well as possible income-generation benefits,
have not yet been studied. Therefore, field experiments on low, medium and highly saline soils were conducted using four sorghum
cultivars (S. vulgare, S. cernuum, S. durra, and S. technicum). The effect of soil salinity on biomass, stover and grain yield, the baking and feed quality, and total water soluble salt
(TDS) accumulation, was assessed according to varieties, plant fractions and growth phases. Results showed that S. cernuum had the highest grain yield on the low (5.13 t ha−1), medium (6.05 t ha−1) and highly (3.3 t ha−1) saline soil. S. technicum showed the lowest growth potential under all salinity levels. TDS accumulation varied between 406 and 185 kg ha−1 depending on variety, site, plant fractions and growth stage. Irrespective of the soil salinity levels and varieties, TDS
was highest in stover and leaves, while highest TDS uptake, mainly chlorides and bicarbonates, occurred between booting and
flowering. Baking quality of all varieties was extremely low, whereas the in-vitro feed was assessed as of medium quality.
The findings indicate the scope of local sorghum varieties for phytomelioration of marginal lands in Karakalpakstan, while
concurrently satisfying a wider range of rural livelihood needs. 相似文献
100.
Tamara E.C. Kraus Robert J. Zasoski William R. Horwath 《Soil biology & biochemistry》2004,36(2):309-321
Tannins are purported to be an important factor controlling nitrogen cycling in forest ecosystems, and the ability of tannins to bind proteins in protein-tannin complexes is thought to be the primary mechanism responsible for these effects. In this study, we examined the influence of well-characterized tannins purified from five different plant species on C and N dynamics of a forest soil A horizon. Tannic acid, a commonly used and commercially available hydrolyzable tannin (HT), and cellulose were also included for comparison. With the exception of tannins from huckleberry (Vaccinium ovatum), the amendments increased respiration 1.4-4.0 fold, indicating that they were acting as a microbial C source. Tannic acid was significantly more labile than the five purified tannins examined in this study. All treatments decreased net N mineralization substantially, through greater N immobilization and decreased mineralization. The six tannins inhibited gross ammonification rates significantly more than cellulose. This suggests that added tannins had effects in addition to serving as an alternative C source. Tannins purified from Bishop pine (Pinus muricata) were the only tannins that significantly inhibited potential gross nitrification rates, however, rates were low even in the control soil making it difficult to detect any inhibition. Differences in tannin structure such as condensed versus HTs and the hydroxylation pattern of the condensed tannin B-ring likely explain differences observed among the tannin treatments. Contrary to other studies, we did not find that condensed tannins were more labile and less inhibitory than HTs, nor that shorter chained tannins were more labile than longer chained tannins. In addition to supporting the hypothesis that reduced N availability in the presence of tannins is caused by complexation reactions, our data suggests tannins act as a labile C source leading to increased N immobilization. 相似文献