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31.
PCR primers specific for the Mycobacterium tuberculosis complex were used to detect the presence of Mycobacterium bovis BCG (Pasteur) in soil microcosms and Mycobacterium bovis in environmental samples taken from a farm in Ireland with a history of bovine tuberculosis. M. bovis genes were detected in soil at 4 and 21 months after possible contamination. Gene levels were found in the range of 1 x 10(3) to 3.6 x 10(3) gene copies g of soil(-1), depending on the sampling area. Areas around badger setts had the highest levels of detectable genes and were shown to have the highest levels of gene persistence. M. bovis-specific 16S rRNA sequences were detected, providing evidence of the presence of viable cells in Irish soils. Studies of DNA turnover in soil microcosms proved that dead cells of M. bovis BCG did not persist beyond 10 days. Further microcosm experiments revealed that M. bovis BCG survival was optimal at 37 degrees C with moist soil (-20 kPa; 30% [vol/wt]). This study provides clear evidence that M. bovis can persist in the farm environment outside of its hosts and that climatic factors influence survival rates. 相似文献
32.
The present study aimed to verify (1) whether seasonal increases in neotropical populations of Plutella xylostella are directly provoked by regular influxes of migrants, and (2) whether temporal variation in food availability is the ecological process behind such predictable events. Over 3 years, plants that P. xylostella prefers were cultivated and irrigated in order to provide a continuous and abundant supply of food. Nevertheless, seasonal oscillations in the population of the herbivore still occurred. The hypothesis of seasonal availability of host plants could not explain the population pattern. In April, when the insect was practically extinct from the area, an artificial infestation (immigration) with 10,000 pupae established a precocious population. Therefore, the start of the natural cycles of population growth, during July–August, seems to be due to external factors, rather than an improvement in local conditions for resident individuals. In the beginning of the natural cycles, the increase in the density of adults significantly preceded the increase in immatures. Plutella xylostella does not diapause, and therefore immigration is the proximate cause of the seasonal population increases. Hypotheses about local factors are suggested to explain the decreasing phase of the predictable population cycles. 相似文献
33.
Sweeney FP Courtenay O Ul-Hassan A Hibberd V Reilly LA Wellington EM 《Letters in applied microbiology》2006,43(4):364-369
AIMS: To adapt an immunomagnetic capture (IMC) technique to concentrate and cultivate Mycobacterium bovis from environmental samples including soil, faeces and urine. METHODS AND RESULTS: Cells of Myco. bovis BCG and wild-type Myco. bovis were successfully isolated and cultured from seeded and naturally infected materials respectively. The IMC cell recovery estimated by colony forming units (CFUs) counts ranged from 0.10% to 0.16% for spiked media, and 0.15-0.36% for naturally infected soil and faeces. Recovery estimated by cell counts calculated using semi-quantitative PCR ranged from 80.3% to 88.6% for spiked and 84.1-88.2% for naturally infected material. The differences in the recovery rates estimated by CFUs compared with pixel intensity is likely to be due to clustering of cells on culture plates, thereby underestimating the true cell count. CONCLUSIONS: The IMC techniques can be applied to isolate viable wild type Myco. bovis from naturally contaminated environmental samples. SIGNIFICANCE AND IMPACT OF STUDY: Cultivation of Myco. bovis from environmental samples using traditional methods is extremely problematic. Here, we demonstrate a novel development of IMC techniques that will greatly facilitate the study of the organism in situ in order to assess its epidemiological importance in bovine tuberculosis persistence. 相似文献
34.
New softwares for automated microsatellite marker development 总被引:9,自引:0,他引:9
Martins W de Sousa D Proite K Guimarães P Moretzsohn M Bertioli D 《Nucleic acids research》2006,34(4):e31
Microsatellites are repeated small sequence motifs that are highly polymorphic and abundant in the genomes of eukaryotes. Often they are the molecular markers of choice. To aid the development of microsatellite markers we have developed a module that integrates a program for the detection of microsatellites (TROLL), with the sequence assembly and analysis software, the Staden Package. The module has easily adjustable parameters for microsatellite lengths and base pair quality control. Starting with large datasets of unassembled sequence data in the form of chromatograms and/or text data, it enables the creation of a compact database consisting of the processed and assembled microsatellite containing sequences. For the final phase of primer design, we developed a program that accepts the multi-sequence ‘experiment file’ format as input and produces a list of primer pairs for amplification of microsatellite markers. The program can take into account the quality values of consensus bases, improving success rate of primer pairs in PCR. The software is freely available and simple to install in both Windows and Unix-based operating systems. Here we demonstrate the software by developing primer pairs for 427 new candidate markers for peanut. 相似文献
35.
Gerard M. Wellington 《Oecologia》1982,52(3):311-320
Summary In Panamá, vertical zonation of coral species is well marked; branching corals (Pocillopora spp.) predominate in shallow (1–6 m) water while massive forms (Pavona spp.) occupy the deeper (6–10 m) areas of the reef. To test the hypothesis that this zonation represents differential resource utilization (i.e., niche partitioning of food resources), one year manipulative field experiments were conducted at two depths (1 m and 7 m below Mean Lower Sea Level) assessing the relative contribution of light and zooplankton to the nutrition of three Pacific corals: Pocillopora damicornis, Pavona clavus and Pavona gigantea. Also tested were the related hypotheses that (i) energy for the maintenance and growth of corals comes mainly from light, independent of zooplankton supply and (ii) Porter's model, in which coral morphology is a predictor of the phototrophic-heterotrophic capabilities of a particular species. That is, corals with a branching morphology and a small polyp diameter (and short tentacle length) should be primarily phototrophic while those species with larger polyps and/or a massive form should show a greater degree of heterotrophy.The comparison of caged versus control corals indicated that the branching coral, Pocillopora damicornis (polyp diameter — 1 mm) grew independent of zooplankton supply (>95) but was markedly affected by shading. Pavona clavus (massive form with intermediate size polyps — 2 mm) was also negatively affected by shading but this effect was minimized when zooplankton was present. Surprisingly, under ambient light conditions, the growth of this specics was independent of zooplankton (>95); perhaps indicating a facultative reliance on zooplankton especially in shallow water. The third species, Pavona gigan-tea (massive form with largest polyps — 3 mm) was highly dependent on both light and zooplankton and was unable to compensate for the effects of shading by zooplankton feeding. This high dependence on light was unexpected since large polyps, according to Porter's model, would predict a more heterotrophic existence.Under all treatments, in both shallow and deep water, Pocillopora was found to grow more rapidly than either massive species. Thus, this study indicates that zonation on eastern Pacific reefs cannot be explained by depth-related differences in nutritional requirements among the species present. These results do provide the first long-term, experimental field evidence that corals are largely phototrophic organisms. The validity of Porter's model attempting to correlate phototrophic-heterotrophic abilities to morphological characteristics is, at least, partially verified: species with larger tentacles do appear to utilize zooplankton to a greater extent than those species with smaller tentacles. However, the significance of corallum morphology in predicting the mode of nutrient acquisition is unclear. Rather, behavioral patterns (tentacle expansion-contraction cycles) and location on the reef may be more important factors to consider. 相似文献
36.
Ibrahim MM de Angelis R Lima AS Viana de Carvalho GD Ibrahim FM Malki LT de Paula Bichuete M de Paula Martins W Rocha EM 《PloS one》2012,7(3):e33775
Purpose
Fungi are a major cause of keratitis, although few medications are licensed for their treatment. The aim of this study is to observe the variation in commercialisation of antifungal eye drops, and to predict the seasonal distribution of fungal keratitis in Brazil.Methods
Data from a retrospective study of antifungal eye drops sales from the only pharmaceutical ophthalmologic laboratory, authorized to dispense them in Brazil (Opthalmos) were gathered. These data were correlated with geographic and seasonal distribution of fungal keratitis in Brazil between July 2002 and June 2008.Results
A total of 26,087 antifungal eye drop units were sold, with a mean of 2.3 per patient. There was significant variation in antifungal sales during the year (p<0.01). A linear regression model displayed a significant association between reduced relative humidity and antifungal drug sales (R2 = 0.17,p<0.01).Conclusions
Antifungal eye drops sales suggest that there is a seasonal distribution of fungal keratitis. A possible interpretation is that the third quarter of the year (a period when the climate is drier), when agricultural activity is more intense in Brazil, suggests a correlation with a higher incidence of fungal keratitis. A similar model could be applied to other diseases, that are managed with unique, or few, and monitorable medications to predict epidemiological aspects. 相似文献37.
Thomas L Hodgson DA Wentzel A Nieselt K Ellingsen TE Moore J Morrissey ER Legaie R;STREAM Consortium Wohlleben W Rodríguez-García A Martín JF Burroughs NJ Wellington EM Smith MC 《Molecular & cellular proteomics : MCP》2012,11(2):M111.013797
Bacteria in the genus Streptomyces are soil-dwelling oligotrophs and important producers of secondary metabolites. Previously, we showed that global messenger RNA expression was subject to a series of metabolic and regulatory switches during the lifetime of a fermentor batch culture of Streptomyces coelicolor M145. Here we analyze the proteome from eight time points from the same fermentor culture and, because phosphate availability is an important regulator of secondary metabolite production, compare this to the proteome of a similar time course from an S. coelicolor mutant, INB201 (ΔphoP), defective in the control of phosphate utilization. The proteomes provide a detailed view of enzymes involved in central carbon and nitrogen metabolism. Trends in protein expression over the time courses were deduced from a protein abundance index, which also revealed the importance of stress pathway proteins in both cultures. As expected, the ΔphoP mutant was deficient in expression of PhoP-dependent genes, and several putatively compensatory metabolic and regulatory pathways for phosphate scavenging were detected. Notably there is a succession of switches that coordinately induce the production of enzymes for five different secondary metabolite biosynthesis pathways over the course of the batch cultures. 相似文献
38.
Burgess BL Parkinson PF Racke MM Hirsch-Reinshagen V Fan J Wong C Stukas S Theroux L Chan JY Donkin J Wilkinson A Balik D Christie B Poirier J Lütjohann D Demattos RB Wellington CL 《Journal of lipid research》2008,49(6):1254-1267
Cholesterol homeostasis is of emerging therapeutic importance for Alzheimer's disease (AD). Agonists of liver-X-receptors (LXRs) stimulate several genes that regulate cholesterol homeostasis, and synthetic LXR agonists decrease neuropathological and cognitive phenotypes in AD mouse models. The cholesterol transporter ABCG1 is LXR-responsive and highly expressed in brain. In vitro, conflicting reports exist as to whether ABCG1 promotes or impedes Abeta production. To clarify the in vivo roles of ABCG1 in Abeta metabolism and brain cholesterol homeostasis, we assessed neuropathological and cognitive outcome measures in PDAPP mice expressing excess transgenic ABCG1. A 6-fold increase in ABCG1 levels did not alter Abeta, amyloid, apolipoprotein E levels, cholesterol efflux, or cognitive performance in PDAPP mice. Furthermore, endogenous murine Abeta levels were unchanged in both ABCG1-overexpressing or ABCG1-deficient mice. These data argue against a direct role for ABCG1 in AD. However, excess ABCG1 is associated with decreased levels of sterol precursors and increased levels of SREBP-2 and HMG-CoA-reductase mRNA, whereas deficiency of ABCG1 leads to the opposite effects. Although functions for ABCG1 in cholesterol efflux and Abeta metabolism have been proposed based on results with cellular model systems, the in vivo role of this enigmatic transporter may be largely one of regulating the sterol biosynthetic pathway. 相似文献
39.
Reversal of digestive interactions between Pacific reef corals: Mediation by sweeper tentacles 总被引:2,自引:0,他引:2
Gerard M. Wellington 《Oecologia》1980,47(3):340-343
Summary Aggressive interactions among reef corals involving direct interference through extracoelenteric digestion has previously been considered as a potential mechanism for the maintenance of high species diversity. In this report I show that induced development of sweeper tentacles can reverse initial digestive interactions. In the eastern Pacific these reversals contribute to resource monopolization by fast growing pocilloporid corals. This suggests that other mechanisms must account for the maintenance of local species diversity. 相似文献
40.