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991.
Rita M. Moraes Hemant Lata Joko Sumyanto Ana M. S. Pereira Bianca W. Bertoni Vaishali C. Joshi Nirmal D. Pugh Ikhlas A. Khan David S. Pasco 《Plant Cell, Tissue and Organ Culture》2011,106(2):309-315
Tissue culture techniques have been used to establish and maintain a repository of medicinal Echinacea. In vitro clones obtained from hypocotyls of germinated seeds, varied macroscopically, microscopically and exhibited variation
in immune enhancing activity. Two in vitro produced clones of Echinacea tennesseensis (Beadle) Small (ETN 03 and ETN 11) were identified as high and low activity based on the activation of human monocytes. Phenotypic
analyses of ETN 03 and ETN 11 clones were done using AFLP (Amplified Fragment Length Polymorphism) assay. Results of the AFLP
assay revealed that no mutation has occurred during in vitro multiplication, storage, and acclimatization into soil. Plants
of ETN 03, ETN 11 clones were cultivated for two growing seasons. Extracts of their dry leaves and roots exhibited immune
enhancing activity; however, the variation in activity noticed between clones during micropropagation diminished and was no
longer statistically relevant. 相似文献
992.
Pilar Pérez Aitor Alonso Gloria Zita Rosa Morcuende Rafael Martínez-Carrasco 《Plant Growth Regulation》2011,65(3):439-447
Increases in growth temperature have been observed to affect photosynthesis differently under long-term exposure to ambient-
and twice ambient-air CO2 concentrations. This study investigates the causes of this interaction in wheat (Triticum aestivum L.) grown in the field over two consecutive years under temperature gradient chambers in ambient (370 μmol mol−1) or elevated (700 μmol mol−1) atmospheric CO2 concentrations and at ambient or ambient +4°C temperatures, with either a low or a high nitrogen supply. The photosynthesis-internal
CO2 response curves and the activity, activation state, kcat and amount of Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) were measured, as well as the soluble protein concentration
in flag leaves at ear emergence and 8–15 days after anthesis. A high nitrogen supply increased Vcmax, the Rubisco amount and activity and soluble protein contents, but did not significantly change the Rubisco kcat. Both elevated CO2 and above ambient temperatures had negative effects on Vcmax and Rubisco activity, but at elevated CO2, an increase in temperature did not decrease Vcmax or Rubisco activity in relation to ambient temperature. The amounts of Rubisco and soluble protein decreased with elevated
CO2 and temperature. The negative impact of elevated CO2 on Rubisco properties was somewhat counteracted at elevated temperatures by an increase in kcat. This effect can diminish the detrimental effects on photosynthesis of combined increases of CO2 and temperature. 相似文献
993.
Variation in global codon usage bias among prokaryotic organisms is associated with their lifestyles
Background
It is widely acknowledged that synonymous codons are used unevenly among genes in a genome. In organisms under translational selection, genes encoding highly expressed proteins are enriched with specific codons. This phenomenon, termed codon usage bias, is common to many organisms and has been recognized as influencing cellular fitness. This suggests that the global extent of codon usage bias of an organism might be associated with its phenotypic traits. 相似文献994.
Biotas from all ecosystems need to respond to factors that determine habitat suitability. These factors originate from different
scales. Effects can be assumed to be hierarchical in the order large-scale geographic > regional > local > small-scale in-habitat
factors. We aimed at the identification of general patterns by comparisons between ecosystems (forest floor snails, hololimnic
stream macroinvertebrates) and across scales, and include potential seasonal effects. Sampling sites displayed signs of naturalness,
such as high levels of deadwood accumulation in the forests, or a lack of artificial stream bed fixation plus a “good” to
“high” score for the assemblage-derived Multimetric Index (MMI) in the streams. Terrestrial and aquatic assemblages of non-emergent
taxa fluctuated independent of seasonal effects. They differed in their relative correlation with environmental matrices with
quasi-concentric effects in forests, and longitudinal effects in streams. Large-scale factors, namely geographic position,
strongly influenced assemblage turnover, but the effect is based on a high covariation between geographic position and environmental
factors. We thus extracted variables that best explained species turnover after correcting for spatio-temporal effects. The
terrestrial community assembling was habitat-based and mainly responded to soil acidification, distance to disturbances, and
regional scale deforestation and deciduous/mixed forest cover. The stream assemblages were structured by regional pasture
cover, organic pollution, regional deciduous forest cover and microlithal cover. Apparently, community assembly occurs along
with changes in regional forest cover and the transport of nutrients and matter that can originate from a distance, irrespective
of ecosystem and assumed “naturalness”. 相似文献
995.
Survase SA Jurgens G van Heiningen A Granström T 《Applied microbiology and biotechnology》2011,91(5):1305-1313
Clostridium beijerinckii DSM 6423 was studied using different continuous production methods to give maximum and stable production of isopropanol and
n-butanol. In a single-stage continuous culture, when wood pulp was added as a cell holding material, we could increase the
solvent productivity from 0.47 to 5.52 g L−1 h−1 with the yield of 54% from glucose. The overall solvent concentration of 7.51 g L−1 (39.4% isopropanol and 60.6% n-butanol) with the maximum solvent productivity of 0.84 g L−1 h−1 was obtained with two-stage continuous culture. We were able to run the process for more than 48 overall retention times
without losing the ability to produce solvents. 相似文献
996.
Zorrilla-Fontanesi Y Cabeza A Domínguez P Medina JJ Valpuesta V Denoyes-Rothan B Sánchez-Sevilla JF Amaya I 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(5):755-778
Breeding for fruit quality traits in strawberry (Fragaria × ananassa, 2n = 8x = 56) is complex due to the polygenic nature of these traits and the octoploid constitution of this species. In order to
improve the efficiency of genotype selection, the identification of quantitative trait loci (QTL) and associated molecular
markers will constitute a valuable tool for breeding programs. However, the implementation of these markers in breeding programs
depends upon the complexity and stability of QTLs across different environments. In this work, the genetic control of 17 agronomical
and fruit quality traits was investigated in strawberry using a F1 population derived from an intraspecific cross between two contrasting selection lines, ‘232’ and ‘1392’. QTL analyses were
performed over three successive years based on the separate parental linkage maps and a pseudo-testcross strategy. The integrated
strawberry genetic map consists of 338 molecular markers covering 37 linkage groups, thus exceeding the 28 chromosomes. 33
QTLs were identified for 14 of the 17 studied traits and approximately 37% of them were stable over time. For each trait,
1–5 QTLs were identified with individual effects ranging between 9.2 and 30.5% of the phenotypic variation, indicating that
all analysed traits are complex and quantitatively inherited. Many QTLs controlling correlated traits were co-located in homoeology
group V, indicating linkage or pleiotropic effects of loci. Candidate genes for several QTLs controlling yield, anthocyanins,
firmness and l-ascorbic acid are proposed based on both their co-localization and predicted function. We also report conserved QTLs among
strawberry and other Rosaceae based on their syntenic location. 相似文献
997.
Variation in the shell colour and banding polymorphism in the land snail Cepaea nemoralis was studied in 260 populations in the region of Gdańsk, northern Poland. Unlike in other regions of Poland, many populations
contain brown shells. Populations from shaded habitats have higher frequencies of brown than those from open and intermediate
habitats, largely at the expense of yellow shells. Nearly all brown shells are also unbanded. Apart from this disequilibrium,
banding morphs among yellow and pink shells show no relationship to habitat. There are no broad geographical trends in morph-frequencies,
but there are very strong correlations among populations very close together, revealed both by pairwise analysis and Moran’s
I. Principal Component Analyses show that these correlations relate to overall genetic similarity at the loci involved. The
populations are at the north-eastern limits of the species’ range; habitats are mostly anthropogenic, and comparisons with
studies in two urban areas (Wrocław, SW Poland, and Sheffield, central England) suggest that the patterns of variation seen
are a product of human transport of propagules followed by local dispersal. The effect of habitat here is much less marked
than in regions much further west, but it indicates that natural selection has occurred. 相似文献
998.
999.
Paul Bangirana Peter Allebeck Michael J Boivin Chandy C John Connie Page Anna Ehnvall Seggane Musisi 《BMC neurology》2011,11(1):96
Background
Infection with severe malaria in African children is associated with not only a high mortality but also a high risk of cognitive deficits. There is evidence that interventions done a few years after the illness are effective but nothing is known about those done immediately after the illness. We designed a study in which children who had suffered from severe malaria three months earlier were enrolled into a cognitive intervention program and assessed for the immediate benefit in cognitive, academic and behavioral outcomes. 相似文献1000.
Masson pine (Pinus massoniana L.) trees in the Pearl River Delta have shown growth decline since late 1980s, particularly those around industrially polluted
regions. As nitrogen is an important nutritional element composing functional proteins, structural proteins and photosynthetic
machinery, investigation on nitrogen allocation is helpful to understand nutrient alteration and its regulation mechanism
in response to pollution stress. Current year (C) and 1-year old needles (C + 1) of five mature trees were sampled in industrially
polluted site and unpolluted natural reserve for bioassay. Needles of declining trees had significantly higher leaf nitrogen
per unit area (NL) but lower photosynthetic capacity (P
max), which resulted in lower photosynthetic nitrogen use efficiency (PNUE) than those of healthy trees. Nitrogen fraction to
the photosynthetic apparatus in the C and C + 1 needles at polluted site was 27 and 22%, significantly lower than the corresponding
healthy needles (48 and 32%). The content of structural proteins was positively correlated with NL in C and C + 1 needles. Moreover, the C and C + 1 needles of declining trees had about 1.8 times structural protein as those
of healthy trees, suggesting that more nitrogen allocation to structural protein are needed for stronger structural defenses
under polluted stress. Decreases in PNUE of declining pine trees could be partially explained by increases in structural protein
nitrogen. 相似文献