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91.
产β—葡萄糖苷酶真菌诱变菌株快速筛选方法 总被引:1,自引:0,他引:1
报道了一种快速筛选产β-葡萄糖管酶真菌诱变菌株的方法。该法利用ρNPG经β-葡萄糖苷酶水解,水解产物ρNP在碱性条件下显色的原理。采用自制的特殊初筛平皿.经一年多的实践应用表明此法具有简便、灵敏、筛子消耗量小、筛选效率高等优点。 相似文献
92.
J. F. Esquivel 《Entomologia Experimentalis et Applicata》2011,140(2):163-170
Southern green stink bugs, Nezara viridula (L.) (Hemiptera: Pentatomidae), and related species are significant pests of cotton, Gossypium hirsutum L. (Malvaceae), in the USA Cotton Belt. Using their stylets, adults introduce pathogens of cotton into cotton bolls, and preliminary data indicate nymphs can also ingest these pathogens. However, data are lacking regarding stylet penetration potential of N. viridula nymphs, and records of stylet penetration by adults are typically determined after damage has occurred. In this study, rostral segments of all developmental stages of N. viridula were measured to estimate potential stylet penetration depth using a novel mathematical model. Overall mean stylet penetration estimates for all stages ranged from 135.3 μm for first instars to 2 389.3 μm for adult females. Potential stylet penetration significantly increased as the insect progressed through nymphal stages. Penetration was also significantly affected by insect posture while feeding. Overall minimum and maximum observed lengths of rostrum ranged from 835.3 μm (first instars) to 7 088.2 μm (adult females), and mean rostral lengths were significantly different between all stages. This report establishes conservative baselines of potential stylet penetration depths by all nymphal stages and both adult sexes of N. viridula. Additionally, the model presented here can be used to estimate potential stylet penetration for other Hemiptera and closely related insects with similar modes of feeding. In conjunction with crop phenology data, accurate estimates of potential stylet penetration will allow more proactive approaches to pest management in a wide range of high‐value cash crops affected worldwide by N. viridula. 相似文献
93.
Enrique Gino Medrano Jesus Esquivel Alois Bell Jeremy Greene Phillip Roberts Jack Bacheler James Marois David Wright Robert Nichols Juan Lopez 《Current microbiology》2009,59(4):405-412
Recently, we showed that the southern green stink bug (SGSB), Nezara viridula (L.), can transmit Pantoea agglomerans (Ewing and Fife), an opportunistic bacterium, into green cotton bolls resulting in plant disease. Here, we hypothesized that
our established model could be used to determine if the SGSB was a general, non-discriminate vector by using two other opportunistic
bacterial pathogens of bolls (Pantoea
ananatis [Serano] and Klebsiella
pneumoniae [Schroeter]) and the known fungal pathogen Nematospora coryli (Peglion). Variants of P. ananatis (strain Pa-1R) and K. pneumoniae (strain Kp 5-1R) selected for rifampicin (Rif) resistance were used as bacterial opportunists. N.
coryli was detected only from laboratory-reared SGSB directly exposed to the fungus. Both Pa-1R and Kp 5-1R were recovered from
SGSB previously provided a contaminated food source (2 days), sterile food (5 days), and then harvested after being caged
on bolls (2 days) at levels reaching 103 and 104 colony forming units (cfus) per insect, respectively. However, bolls caged with insects infected with Pa-1R or Kp 5-1R and
with evidence of feeding did not become diseased nor were either opportunists detected from boll tissues. Insects infected
with N. coryli transmitted the pathogen, which resulted in diseased bolls and fungi concentrations reached 106 cfus/g locule tissue at 2 weeks following the caging period. Notably, each of the three pathogens independently caused boll
disease when mechanically inoculated using a needle puncture. Generally, these results suggest that cotton pathogen acquisition
by the SGSB was not sufficient to determine whether the insects were disease vectors of the opportunists. 相似文献
94.
95.
96.
N Kanzaki RM Giblin-Davis RH Scheffrahn H Taki A Esquivel KA Davies EA Herre 《PloS one》2012,7(8):e43865
Background
The molecular operational taxonomic unit (MOTU) has recently been applied to microbial and microscopic animal biodiversity surveys. However, in many cases, some of the MOTUs cannot be definitively tied to any of the taxonomic groups in current databases. To surmount these limitations, the concept of “reverse taxonomy” has been proposed, i.e. to primarily list the MOTUs with morphological information, and then identify and/or describe them at genus/species level using subsamples or by re-isolating the target organisms. Nevertheless, the application of “reverse taxonomy” has not been sufficiently evaluated. Therefore, the practical applicability of “reverse taxonomy” is tested using termite-associated nematodes as a model system for phoretic/parasitic organisms which have high habitat specificity and a potential handle (their termite host species) for re-isolation attempts.Methodology
Forty-eight species (from 298 colonies) of termites collected from the American tropics and subtropics were examined for their nematode associates using the reverse taxonomy method and culturing attempts (morphological identification and further sequencing efforts). The survey yielded 51 sequence types ( = MOTUs) belonging to 19 tentatively identified genera. Within these, four were identified based on molecular data with preliminary morphological observation, and an additional seven were identified or characterized from successful culturing, leaving eight genera unidentified.Conclusions
That 1/3 of the genera were not successfully identified suggests deficiencies in the depth of available sequences in the database and biological characters, i.e. usually isolated as phoretic/parasitic stages which are not available for morphological identification, and too many undiscovered lineages of nematodes. Although there still is the issue of culturability of nematodes, culturing attempts could help to make reverse taxonomy methods more effective. However, expansion of the database, i.e., production of more DNA barcodes tied to biological information by finding and characterizing additional new and known lineages, is necessary for analyzing functional diversity. 相似文献97.
Protein degradation in C3 and C4 plants with particular reference to ribulose bisphosphate carboxylase and glycolate oxidase 总被引:9,自引:0,他引:9
Determining the degradation characteristics of proteins is difficult due to
the lack of appropriate methodologies, particularly in the case of leaf
proteins. Previous studies suggest that ribulose bisphosphate carboxylase
(RuBP carboxylase; EC 4.1.1.39) proteolysis may be fundamentally different
in C3 and C4 plants. To test this hypothesis, the relative degradation
rates of the total soluble protein, RuBP carboxylase and glycolate oxidase
(EC 1.1.3.1) in the second leaves of intact C3 (Triticum
aestivum L.) and C4 (Zea mays L) and
Sorghum bicolor L.)plants was measured. The
methodology utilized involved an efficient procedure to label the leaf
proteins, the use of a double-labelling method to measure protein
degradation and a single-step purification of the labelled proteins under
study. RuBP carboxylase is subjected to continuous degradation in all
plants investigated. Its rate of degradation is higher for Z.
mays, intermediate for T. aestivum and
lower for S. bicolor. When the rate of RuBP
carboxylase degradation was compared with that of the total soluble protein
a differential pattern was obtained for the plant species examined: whereas
maize presents a faster rate of RuBP carboxylase degradation than of the
total soluble protein, wheat and sorghum show similar rates. However, the
rate of RuBP carboxylase proteolysis in the three plant species studied is
much lower than the rate of glycolate oxidase degradation. The results
obtained indicate that, under the conditions of study, the degradation
characteristics of plant RuBP carboxylase, as those of glycolate oxidase,
are species specific, in a way suggesting that they do not depend on the
type of photosynthetic metabolism of the species considered (C3 or
C4). 相似文献
98.
R Docampo F S Cruz A Boveris R P Muniz D M Esquivel 《Archives of biochemistry and biophysics》1978,186(2):292-297
β-Lapachone, an antimicrobial agent, was reduced by Trypanosoma cruzi epimastigotes to a semiquinone radical. It markedly increased the generation of superoxide anion and hydrogen peroxide in intact cells. Using NADH as electron donor, β-lapachone also increased significantly the rate of H2O2 generation in epimastigote homogenates. Incubation of epimastigotes with β-lapachone stimulated lipid peroxidation. 相似文献
99.
100.
Mário C BarrosoJúnior Guilherme P Esteves Thiago P Nunes Lucia MG Silva Alvaro CD Faria Pedro L Melo 《Biomedical engineering online》2011,10(1):14