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981.
? Premise of the study: Polyploidy has been shown to affect different plant traits and modulate interactions between plants and other organisms, such as pollinators and herbivores. However, no information is available on whether it can also shape the functioning of mycorrhizal symbiosis. ? Methods: The mycorrhizal growth response was assessed for three angiosperms with intraspecific ploidy variation. Different cytotypes of Aster amellus, Campanula gentilis, and Pimpinella saxifraga were either left uninoculated or were inoculated with arbuscular mycorrhizal (AM) fungi in a pot experiment. After 3 mo of cultivation in a greenhouse, plant growth, phosphorus concentration in the shoot biomass, and development of the AM symbiosis were evaluated. ? Key results: No significant ploidy-specific differences in AM development were recorded. The inoculation led to consistently greater phosphorus uptake; however, the effect on plant growth differed considerably among plant species, populations, ploidy levels, and AM species. A salient ploidy-specific response was observed in A. amellus. Whereas diploid plants benefited from AM inoculation, the hexaploids consistently showed negative or no-growth responses (depending on the AM species). In contrast to A. amellus, no interactions between inoculation and ploidy were observed in C. gentilis and P. saxifraga. ? Conclusions: The first evidence is provided of a ploidy-specific response of a mycotrophic plant to AM fungi. Our results demonstrate the complexity of interaction between plants and associated AM fungi, with the ploidy level of the host plant being one component that may modulate the functioning of the symbiosis. 相似文献
982.
Bauera E Williams BA Voigt C Mosenthin R Verstegen MW 《Archives of animal nutrition》2010,64(5):394-411
Increased carbohydrate fermentation, compared with protein fermentation, could benefit gut health. In two in vitro experiments, the effect of carbohydrate-rich feed ingredients on fermentation characteristics of ileal chyme from pigs was assessed, using the cumulative gas production technique. Ingredients of the first experiment included gums, inulins, pectins, transgalacto-oligosaccharides, lactose and xylan. In the second experiment, a gum, pectin and transgalacto-oligosaccharides were added at different starting weights, to determine their effects on fermentation characteristics of chyme, in relation to differences in the carbohydrate concentrations. In comparison to fermentation of chyme alone, added carbohydrates led to higher total gas production (p < 0.05), faster maximum rate of gas production (except for xylan) (p < 0.05), and a decreased branched-chain fatty acids to straight chain fatty acids ratio (BCR) (p < 0.05). In the second experiment, for all carbohydrate ingredients, the BCR decreased with increasing starting weights (p < 0.05). If these supplemented dietary carbohydrates were to reach the terminal ileum of the living animal, carbohydrate fermentation in the large intestine could be stimulated, which is known to have beneficial effects on host health. 相似文献
983.
984.
985.
Genotypic and environmental variation in specific leaf area in a widespread Alpine plant after transplantation to different altitudes 总被引:1,自引:0,他引:1
Specific leaf area (SLA) is an important plant functional trait as it is an indicator of ecophysiological characteristics
like relative growth rate, stress tolerance and leaf longevity. Substantial intraspecific variation in SLA is common and usually
correlates with environmental conditions. For instance, SLA decreases with increasing altitude, which is understood as adjustment
to temperature. It is generally assumed that intraspecific variation is mostly the result of environmentally induced phenotypic
plasticity, but genetic effects may also be present, due to local adaptation or genetic drift. In this study, genotypic and
environmental effects on SLA were experimentally separated for the widespread Alpine bell flower Campanula thyrsoides by transplanting plants to three common gardens at contrasting altitudes (600, 1,235 and 1,850 m a.s.l.). Seeds were sampled
from 18 populations in four phylogeographic regions within the European Alps. A strong plastic response was observed: SLA
decreased with increasing altitude of the common gardens (22.0% of variation). The phylogeographic regions were differentiated
in SLA in the common gardens (10.1% of variation), indicating that SLA is at least partly genetically determined. Plants from
the six easternmost populations experienced a submediterranean climate and showed decreased SLA values in the three common
gardens compared to populations to the west, which may be explained as adaptation to drought. Within these submediterranean
populations, SLA decreased with altitude of origin in two out of three common gardens. Concluding, SLA shows strong phenotypic
plasticity as well as substantial genetic effects, the latter probably being the result of adaptation to local conditions
rather than genetic drift. 相似文献
986.
Eva Š?astná 《Steroids》2010,75(10):721-1636
A series of keto steroids were reduced with sodium borohydride in the presence of cerium(III) chloride or samarium(III) iodide (Luche reduction). The ratios of axial and equatorial alcohols were determined by HPLC and the results were compared with those obtained by a standard sodium borohydride reduction. The best results were obtained with the 2-keto derivative 1, 7-keto derivatives 5 and 6, and 12-keto derivative 8 where the cerium(III) ion addition resulted in the inversion of the axial/equatorial ratios. The Luche reduction of the 20-keto derivative 11 improved the proportion of the (20S)-alcohol in a mixture of (20S)/(20R) alcohols up to 35% from 5% in a standard sodium borohydride reduction. 相似文献
987.
Célia Ferreira Sónia Silva Fábio Faria-Oliveira Eva Pinho Mariana Henriques Cândida Lucas 《BMC microbiology》2010,10(1):238
Background
GUP1 gene was primarily identified in Saccharomyces cerevisiae being connected with glycerol uptake defects in association with osmotic stress response. Soon after, Gup1p was implicated in a complex and extensive series of phenotypes involving major cellular processes. These include membrane and wall maintenance, lipid composition, bud-site selection, cytoskeleton orientation, vacuole morphology, secretory/endocytic pathway, GPI anchors remodelling, and lipid-ordered domains assembly, which is compatible with their inclusion in the Membrane Bound O-acyl transferases (MBOAT) family. In mammals, it has been described as a negative regulator of the Sonic hedgehog pathway involved in morphogenesis, differentiation, proliferation, among other processes. 相似文献988.
Siegbert Rieg Benjamin Meier Eva Fähnrich Anja Huth Dirk Wagner Winfried V Kern Hubert Kalbacher 《BMC microbiology》2010,10(1):61
Background
Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the activity of human α-defensins human neutrophil peptides (HNPs) 1-3, human β-defensin (hBD)-3 and cathelicidin LL-37 as well as bovine β-defensins lingual and tracheal antimicrobial peptides (LAP, TAP) and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. 相似文献989.
Eva García-Ruiz Diana Maté Antonio Ballesteros Angel T Martinez Miguel Alcalde 《Microbial cell factories》2010,9(1):17
Background
In the picture of a laboratory evolution experiment, to improve the thermostability whilst maintaining the activity requires of suitable procedures to generate diversity in combination with robust high-throughput protocols. The current work describes how to achieve this goal by engineering ligninolytic oxidoreductases (a high-redox potential laccase -HRPL- and a versatile peroxidase, -VP-) functionally expressed in Saccharomyces cerevisiae. 相似文献990.
Eva Falck Sandra Karlsson Jessica Carlsson Gisela Helenius Mats Karlsson Karin Klinga-Levan 《Cancer cell international》2010,10(1):46
Glutathione peroxidase 3 (GPX3) is one of the key enzymes in the cellular defense against oxidative stress and the hepatocyte
growth factor receptor, (MET) has been suggested to be influenced by the GPX3 gene expression. In a previous microarray study performed by our group, Gpx3 was identified as a potential biomarker for rat endometrial adenocarcinoma (EAC), since the expression was highly downregulated
in rat EAC tumors. Herein, we have investigated the mRNA expression and Gpx3 and Met in rat EAC by real time quantitative PCR (qPCR), and the methylation status of Gpx3. In addition we have examined the expression of GPX3 and MET in 30 human EACs of different FIGO grades and 20 benign endometrial tissues. We found that the expression of GPX3 was uniformly down regulated in both rat and human EAC, regardless of tumor grade or histopathological subtype, implying
that the down-regulation is an early event in EAC. The rate of Gpx3 promoter methylation reaches 91%, where biallelic methylation was present in 90% of the methylated tumors. The expression
of the Met oncogene was slightly upregulated in EACs that showed loss of expression of Gpx3, but no tumor suppressor activity of Gpx3/GPX3 was detected. Preliminary results also suggest that the production of H2O2 is higher in rat endometrial tumors with down-regulated Gpx3 expression. A likely consequence of loss of GPX3 protein function would be a higher amount of ROS in the cancer cell environment.
Thus, the results suggest important clinical implications of the GPX3 expression in EAC, both as a molecular biomarker for EAC and as a potential target for therapeutic interventions. 相似文献