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91.
D. R. Lynch J. C. Miller L. M. Kawchuk C. A. Schaupmeyer J. Holley J. Panford D. K. Fujimoto D. Waterer J. Wahab B. Rex M. S. Goettel 《American Journal of Potato Research》2000,77(4):241-244
AC Stampede Russet has a maincrop maturity, and the tubers reach maximum size in western Canada in early to mid-September. The tubers are attractive with russet skin, shallow eyes, an oblong shape, and are very uniform in size. The cultivar is suitable for french fry or fresh market (count carton) production. It appears to perform best under irrigated conditions. The cultivar provides the industry with a russet-skinned, dual purpose russet cultivar with high yield, low defect levels, excellent fresh market appeal, and good storage quality for both the french fry and fresh market industries. 相似文献
92.
Jacobs Z Roberts RG Galbraith RF Deacon HJ Grün R Mackay A Mitchell P Vogelsang R Wadley L 《Science (New York, N.Y.)》2008,322(5902):733-735
The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa-the Still Bay and Howieson's Poort industries-that are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies. We report ages for nine sites from varied climatic and ecological zones across southern Africa that show that both industries were short-lived (5000 years or less), separated by about 7000 years, and coeval with genetic estimates of population expansion and exit times. Comparison with climatic records shows that these bursts of innovative behavior cannot be explained by environmental factors alone. 相似文献
93.
94.
Effect of the pyrrole polymerization mechanism on the antioxidative activity of nonenzymatic browning reactions 总被引:2,自引:0,他引:2
The present investigation was undertaken to study how the antioxidative activity (AA) of nonenzymatic browning reactions is changing at the same time that the browning (by the pyrrole polymerization mechanism) is being produced. The antioxidative activities of eight model pyrroles (pyrrole, 1-methylpyrrole, 2,5-dimethylpyrrole, 1,2,5-trimethylpyrrole, 2-acetylpyrrole, 2-acetyl-1-methylpyrrole, pyrrole-2-carboxaldehyde, and 1-methyl-2-pyrrolecarboxaldehyde) as well as the browning reaction of 2-(1-hydroxyethyl)-1-methylpyrrole (HMP) and the dimer (DIM) produced during HMP browning were determined. The results obtained suggest that the AAs observed in nonenzymatic browning reactions are the result of the AAs of the different oxidized lipid/amino acid reaction products formed. Thus, the different pyrrole derivatives produced in these reactions had different AAs, and the highest AAs were observed for alkyl-substituted pyrroles without free alpha-positions. Because some of these pyrrole derivatives are implicated in nonenzymatic browning production and this browning production implies the loss of hydroxyl groups and the transformation of some pyrroles with one type of substitution into others, changes in AA during browning production were observed, and the resulting DIM derivative was more antioxidant than HMP or higher polymers. These results explain the AA observed in fatty acid/protein mixtures after slight oxidation and suggest that, when the pyrrole polymerization mechanism is predominant, slightly browned samples may be more antioxidant than samples in which nonenzymatic browning has been highly developed. 相似文献
95.
Comparison of two procedures to evaluate phosphate‐fertilizing field trials Growth response of agricultural crops to different input levels (e.g., fertilizer rates) can be described by the “law of diminishing increments”, which has been formulated mathematically amongst others by Mitscherlich (1928) and von Boguslawski and Schneider (1962, 1963, 1964). In the present paper, the economically optimal phosphate‐fertilizer requirements in 43 long‐term phosphate (P)‐fertilization experiments were calculated using equations on the basis of the yield functions of Mitscherlich or von Boguslawski and Schneider, respectively. For three field trials with linear or disproportionately high yield responses on P fertilization, none of the two procedures could be used. The same held for four trials with maximum yields already appearing at the first fertilization level. Similar P‐fertilization optima were calculated for 36 trials following the “law of diminishing increments”, resulting in a highly significant correlation (R2 = 0.946) between both procedures. The correlation coefficients between the phosphate balance at the calculated optimum profitability and CAL‐P content in the soils at trial start were R2 = 0.70 (Mitscherlich, 1928) and R2 = 0.65 (von Boguslawski and Schneider, 1962, 1963, 1964), respectively. An optimal soil P content of 8–10 mg CAL‐P (100 g soil)–1 was deduced. Both methods are applicable to calculate the optimum phosphate‐fertilizer requirement if yield effects due to P fertilization follow the “law of diminishing increments” and the increments of fertilization levels in each trial are established in a way that diminishing yield increments can be expected. 相似文献
96.
McDougall GJ Gordon S Brennan R Stewart D 《Journal of agricultural and food chemistry》2005,53(20):7878-7885
Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrate from black currant (Ribes nigrum L.). These compounds had UV-vis spectra similar to those of delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, but eluted before all previously described anthocyanins on reversed phase HPLC. Mass spectrometric data indicated that they were rutinoside derivatives of novel aglycons 304 amu greater than delphinidin and cyanidin, respectively. The compounds were partly purified by semipreparative HPLC and gave MS and MS2 spectra consistent with anthocyanin rutinosides covalently linked to epigallocatechin or gallocatechin. These compounds are similar in structure to compounds thought to influence color and quality in red wines and strawberry juice products. There was also evidence for the presence of a range of other flavanol-anthocyanin condensation products. The compounds were present at differing levels in juices of 10 black currant varieties, which were roughly correlated to the content of the parent anthocyanins. The flavanol-anthocyanin products were present in polyphenol-enriched concentrates obtained by solid phase extraction, in commercially produced concentrates, and in fresh extracts of black currants. This suggests that the compounds were not artifacts formed during concentration or purification. However, differences in their comparative contents may be related to the lability of the parent anthocyanins during processing. Although present at low levels, the flavanol-anthocyanin products may influence color or quality parameters of black currant juices, and they may confer enhanced stability to the biological activities reported for their anthocyanin parents. 相似文献
97.
98.
Rex A. Omonode Tony J. Vyn Doug R. Smith Pter Hegymegi Anita Gl 《Soil & Tillage Research》2007,95(1-2):182-195
Although the Midwestern United States is one of the world's major agricultural production areas, few studies have assessed the effects of the region's predominant tillage and rotation practices on greenhouse gas emissions from the soil surface. Our objectives were to (a) assess short-term chisel (CP) and moldboard plow (MP) effects on soil CO2 and CH4 fluxes relative to no-till (NT) and, (b) determine how tillage and rotation interactions affect seasonal gas emissions in continuous corn and corn–soybean rotations on a poorly drained Chalmers silty clay loam (Typic Endoaquoll) in Indiana. The field experiment itself began in 1975. Short-term gas emissions were measured immediately before, and at increasing hourly intervals following primary tillage in the fall of 2004, and after secondary tillage in the spring of 2005, for up to 168 h. To quantify treatment effects on seasonal emissions, gas fluxes were measured at weekly or biweekly intervals for up to 14 sampling dates in the growing season for corn. Both CO2 and CH4 emissions were significantly affected by tillage but not by rotation in the short-term following tillage, and by rotation during the growing season. Soil temperature and moisture conditions in the surface 10 cm were significantly related to CO2 emissions, although the proportion of variation explained by temperature and moisture was generally very low (never exceeded 27%) and varied with the tillage system being measured. In the short-term, CO2 emissions were significantly higher for CP than MP and NT. Similarly, mean seasonal CO2 emissions during the 2-year period were higher for CP (6.2 Mg CO2-C ha−1 year−1) than for MP (5.9 Mg CO2-C ha−1 year−1) and NT (5.7 Mg CO2-C ha−1 year−1). Both CP and MP resulted in low net CH4 uptake (7.6 and 2.4 kg CH4-C ha−1 year−1, respectively) while NT resulted in net emissions of 7.7 kg CH4-C ha−1 year−1. Mean emissions of CO2 were 16% higher from continuous corn than from rotation corn during the two growing seasons. After 3 decades of consistent tillage and crop rotation management for corn and soybean producing grain yields well above average in the Midwest, continuous NT production in the corn–soybean rotation was identified as the system with the least soil-derived C emissions to the atmosphere from among those evaluated prior to and during corn production. 相似文献
99.
Edurne Aguiriano Magdalena Ruiz Rosario Fité Jose M. Carrillo 《Genetic Resources and Crop Evolution》2006,53(8):1543-1552
In this work gliadin proteins were used to analyse the genetic variability in a sample of the durum wheat Spanish collection
conserved at the CRF-INIA. In total 38 different alleles were identified at the loci Gli-A1, Gli-A3, Gli-B5, Gli-B1, Gli-A2 and Gli-B2. All the gliadin loci were polymorphic, possessed large genetic diversity and small and large differentiation within and
between varieties, respectively. The Gli-A2 and Gli-B2 loci were the most polymorphic, the most fixed within varieties and the most useful to distinguish among varieties. Alternatively,
Gli-B1 locus presented the least genetic variability out of the four main loci Gli-A1, Gli-B1, Gli-A2 and Gli-B2. The Gli-B1 alleles coding for the gliadin γ-45, associated with good quality, had an accumulated frequency of 69.7%, showing that the
Spanish germplasm could be a good source for breeding quality. The Spanish landraces studied showed new gliadin alleles not
catalogued so far. These new alleles might be associated with specific Spanish environment factors. The large number of new
alleles identified also indicates that durum wheat Spanish germplasm is rather unique. 相似文献
100.
Daoubi M Hernández-Galán R Benharref A Collado IG 《Journal of agricultural and food chemistry》2005,53(17):6673-6677
Eleven beta-himachalene derivatives were tested, using the poisoning food technique, for their potential antifungal activity against the phytopathogen Botrytis cinerea. Compounds 1-11 displayed moderate activity, whereas the 6,7-diol derivative (12) produced an inhibition of 91% after 6 days. The microbial transformation of 12 was investigated and yielded four new compounds hydroxylated at positions C-5 (13), C-2 (14), C-4 (15), and C-12 (16). The structures were established on the basis of their spectroscopic data including two-dimensional NMR analysis (HMQC, HMBC, nOesy) and nOes. The results obtained from biotransformation experiments shed further light on the detoxification mechanism of the phytopathogenic fungus against this compound and give an indication of the structural modifications that may be necessary if substrates of this type are to be further developed as selective fungal control agents for B. cinerea. 相似文献