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101.
Changes in tomato fruit expansion rate and carbohydrate content have been assessed during treatments designed to alter the carbon import rate. Because fruit expansion is sensitive to plant water status, the relationship with carbon import is difficult to assess, and thus, the diameter growth rate of young fruit was measured on plants maintained at positive water potentials. The detached top metre of a tomato plant was supplied with water, through the cut stem base, at a pressure of 0.08 MPa. Developing fruit on the stem continued to grow at high rates for up to 2 d. Fruit diameter growth rate after plant detachment was directly proportional to temperature. Plants acclimated to different continuous irradiances for 5 d before detachment gave fruit growth rates after plant detachment which were directly proportional to the irradiance up to 7 MJ m−2d−1 photosynthetically active radiation (PAR). In continuous darkness, fruit growth rate remained unchanged for 20 h and then declined to less than 40% of the original rate over the following 30 h. On re-exposure to light, about 5 h elapsed before fruit growth rate increased but the growth rate stabilized at approximately 50% of the rate in continuously illuminated plants. During darkness, both fruit starch and hexose content decreased in comparison to illuminated controls, but on re-illumination, carbohydrate content increased before carbon was allocated to structural growth. Heat-killing the phloem of the fruit pedicel caused an immediate, but temporary, cessation of growth. After a partial recovery, expansion growth continued, but more slowly than in untreated fruit and at steadily declining rates. Starch and hexose sugars were not used to provide substrates for growth and starch synthesis was maintained. Continuing cell expansion was assumed to have been supported by water import via the xylem. Thus, fruit expansion may be related to carbon accumulation in most circumstances, but the changing allocation of imported carbon to storage and cell expansion may modify this relationship. 相似文献
102.
PATRICIA S. SHERROD GERALDINE A. JUNE WALLACE H. ANDREWS R. MIGUEL AMAGUANA THOMAS S. HAMMACK 《Journal of Rapid Methods and Automation in Microbiology》1994,3(1):37-57
The sensitivity of the original versus the modified Salmonella-Tek enzyme immunoassay (EIA) was compared for recovery of Salmonella spp. from selected low-moisture foods. Serial tenfold dilutions were inoculated into incubated post enrichment media (dilution-to-extinction approach). Results indicated no significant difference between the original and modified Salmonella-Tek EIAs. A comparison of the modified Salmonella-Tek EIA and the modified GENE-TRAK Salmonella assay, using the same approach, also showed no significant differences.
The effectiveness of the assays was then compared using a second approach (dry bulk inoculation). A lyophilized culture was inoculated into bulk food. Replicate 25-g test portions were used in a 3-way comparison of the effectiveness of the modified Salmonella-Tek EIA, the modified GENE-TRAK Salmonella assay, and the standard culture method approved by the Association of Official Analytical Chemists (AOAC) International and recommended in the Food and Drug Administration's Bacteriological Analytical Manual. Of 460 test portions examined, 307 gave positive reactions with the modified Salmonella-Tek EIA, 298 with the modified GENE-TRAK Salmonella assay, and 292 with the AOAC/BAM culture method. 相似文献
The effectiveness of the assays was then compared using a second approach (dry bulk inoculation). A lyophilized culture was inoculated into bulk food. Replicate 25-g test portions were used in a 3-way comparison of the effectiveness of the modified Salmonella-Tek EIA, the modified GENE-TRAK Salmonella assay, and the standard culture method approved by the Association of Official Analytical Chemists (AOAC) International and recommended in the Food and Drug Administration's Bacteriological Analytical Manual. Of 460 test portions examined, 307 gave positive reactions with the modified Salmonella-Tek EIA, 298 with the modified GENE-TRAK Salmonella assay, and 292 with the AOAC/BAM culture method. 相似文献
103.
Schneider's cell lines 1, 2 and 3 derived from embryonic stages of Drosophila melanogaster were examined by scanning electron microscopy, histochemical staining procedures, and SDS polyacrylamide disc gel electrophoresis. Although the three lines showed some similarities when compared by each of these methods, differences between the lines were observed as well. The surface features of the cells in each line showed morphologic as well as age dependent distinctions when examined in the scanning electron microscope. The intracellular distribution and amount of periodic acid-Schiff positive (PAS+), α-amylase sensitive material was also distinct for each of the lines. Approximately one-third of line 1 cells contained PAS+ hyaluronidase-sensitive material localized within a cytoplasmic vesicle whereas less than 1% of the cells of lines 2 and 3 contained such material. SDS polyacrylamide disc gel electrophoresis revealed PAS+ material in a soluble fraction of line 2 cells and in the 100,000 μ g pellet of line 3 cells, but no PAS+ bands in similar fractions of line 1 cells were detected. 相似文献
104.
PETER ANDREWS 《Zoological Journal of the Linnean Society》1982,74(3):233-244
Relationships of the catarrhine primates based on morphological similarity are presented and then combined with habitat data to determine polarity of ecological change in the catarrhines. The ancestral habitat of two sister-groups is estimated by combining that of the sister groups, so that if they share one habitat type the ancestral condition is taken to be that type, or if they differ the ancestral condition is taken to be both alternatives. Analysed in this way the ancestral habitat preference of the Catarrhini is tropical lowland forest, and while the Hominoidea retain this primitive condition, the Cercopithecoidea are derived with a savanna habitat preference. Most hominoids retain the primitive forest habitat condition, and those groups that are associated with woodland-savanna habitats, notably the ramapitbecines and hominines, therefore share a derived habitat preference. There is no evidence, however, that this arose through common ancestry, and it is concluded that the functional similarities between the two groups could have arisen through parallel adaptation to the same habitat type. Similarly, many of the extant cercopithecoid groups that are now forest living may have re-entered forest independently. The derived savanna habitat preference of the cercopithecoids is linked with a number of morphological characters that also are derived with respect to catarrhine ancestry, and these include their terrestrial and/or their above-branch adaptations, and their specialized digestive, dietary and dental adaptations. In contrast, the hominoids that retain the primitive catarrhine habitat preference also retain the primitive condition in all these characters. 相似文献
105.
Cocksfoot mottle virus (CfMV) and cynosurus mottle virus (CyMV) had similar, but not identical, host-ranges within the Gramineae. Each infected fifteen out of forty-one species tested, considerably fewer than phleum mottle virus (PMV), but unlike PMV both infected Triticum aestivum (wheat), causing a lethal mottle. The species most useful for differentiating CfMV, CyMV and PMV are listed. Some species appear especially susceptible to virus infection. 相似文献
106.
The effects of different applied NO3 concentrations onextension growth and final length and area of leaves 14of five cereals and six pasture grasses of temperate originwere examined. Increased applied NO3 in the range 0.150mol m3; caused decreased duration of growth but increasedgrowth rate and final length of leaves 24 of the cerealsAvena saliva, Hordeum vulgare, Secale cereale x Triticosecaleand Triticum aestivum. For all cereals, increased NO3resulted in increased area of leaves 1-4. Pasture grasses weresupplied either 0.5 or 50 mol m3; NO3. Increasedapplied NO3 (0.550 mol m3) resulted indecreased duration of growth and increased growth rate and finalarea of leaves 14 of Bromus willdenowii leaves 24of Festuca arundinaceae and leaves 3 and 4 of Lolium multiflorum.In addition, length of leaves 3 and 4 of B. willdenowii increasedwith increased NO3. Increased NO3 resulted in increased areaof leaves 24 of Daciylis glomerata and Lolium perenneand leaves 3 and 4 of Phalaris aquatica but had no effect onextension growth of all three species. Avena saliva L., oat, Hordeum vulgare L., barley, Secale cereaie L., rye, x Triticosecale Wittm, triticale, Triticum aestivum L., wheat, Bromus willdenowii Kunth, prairie grass, Dactylis glomerata L., cocksfoot, Festuca arundinaceae Shreb, tall fescue, Lolium multiflorum Lam, Italian ryegrass, Lolium perenne L, perennial ryegrass, Phalaris aquatica L, nitrate,, leaf extension, leaf expansion 相似文献
107.
108.
Chlorophenoxyacetate weed-killers have been tested for the control of aquatic weeds in the canals of the Sudan Gezira. Using water in tanks, it was shown that 10 parts per million of sodium 2-methyl-4-chlorophenoxyacetate (Methoxone) or of sodium 2:4-dichlorophenoxyacetate (Fernoxone) would kill most of the angiospermous water-weeds found in the Gezira area.
Small-scale field experiments, using channels of known water capacity, have shown that not only leaves and stems but also seeds and underground rhizomes were killed in treated stagnant water, provided that the weed-killers were applied as dusts. The water remained toxic to crop plants for approximately 7 weeks after treatment.
In a large-scale experiment in 1950, treating normal irrigation canals, temporary weed clearance was attained, re-infestation was delayed, and one major canal, 4.5 km. long, remained weed-free 12 months after treatment. 相似文献
Small-scale field experiments, using channels of known water capacity, have shown that not only leaves and stems but also seeds and underground rhizomes were killed in treated stagnant water, provided that the weed-killers were applied as dusts. The water remained toxic to crop plants for approximately 7 weeks after treatment.
In a large-scale experiment in 1950, treating normal irrigation canals, temporary weed clearance was attained, re-infestation was delayed, and one major canal, 4.5 km. long, remained weed-free 12 months after treatment. 相似文献
109.
A note on the selection of data transformations 总被引:1,自引:0,他引:1
110.