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101.
We report the first study with the aim to estimate heritability in a wild population, a nest box breeding population of blue tits. We estimated heritability as well as genetic and phenotypic correlations of resting metabolic rate (RMR), body mass and tarsus length with an animal model based on data from a split cross‐fostering experiment with brood size manipulations. RMR and body mass, but not tarsus length, showed significant levels of explained variation but for different underlying reasons. In body mass, the contribution to the explained variation is mainly because of a strong brood effect, while in RMR it is mainly because of a high heritability. The additive variance in RMR was significant and the heritability was estimated to 0.59. The estimates of heritability of body mass (0.08) and tarsus length (0.00) were both low and based on nonsignificant additive variances. Thus, given the low heritability (and additive variances) in body mass and tarsus length the potential for direct selection on RMR independent of the two traits is high in this population. However, the strong phenotypic correlation between RMR and mass (0.643 ± 0.079) was partly accounted for by a potentially strong, although highly uncertain, genetic correlation (1.178 ± 0.456) between the two traits. This indicates that the additive variance of body mass, although low, might still somewhat constrain the independent evolvability of RMR. 相似文献
102.
Charlotte Åström Markus Lindkvist Lage Burström Gunnevi Sundelin J. Stefan Karlsson 《Journal of electromyography and kinesiology》2009,19(3):407-415
Exposure to vibration is suggested as a risk factor for developing neck and shoulder disorders in working life. Mechanical vibration applied to a muscle belly or a tendon can elicit a reflex muscle contraction, also called tonic vibration reflex, but the mechanisms behind how vibration could cause musculoskeletal disorders has not yet been described. One suggestion has been that the vibration causes muscular fatigue. This study investigates whether vibration exposure changes the development of muscular fatigue in the trapezius muscle. Thirty-seven volunteers (men and women) performed a sub-maximal isometric shoulder elevation for 3 min. This was repeated four times, two times with induced vibration and two times without. Muscle activity was measured before and after each 3-min period to look at changes in the electromyography parameters. The result showed a significantly smaller mean frequency decrease when performing the shoulder elevation with vibration (?2.51 Hz) compared to without vibration (?4.04 Hz). There was also a slightly higher increase in the root mean square when exposed to vibration (5.7% of maximal voluntary contraction) compared to without (3.8% of maximal voluntary contraction); however, this was not statistically significant. The results of the present study indicate that short-time exposure to vibration has no negative acute effects on the fatiguing of upper trapezius muscle. 相似文献
103.
Tatiana de Oliveira Sato Helenice Jane Cote Gil Coury Gert-Åke Hansson 《Journal of electromyography and kinesiology》2009,19(4):704-709
Flexible goniometers are useful for direct movement measurements. Crosstalk due to rotation between the endblocks is well known. However, even without any rotation, some crosstalk can occur. The objective of this study was to elucidate the effect of, and compensate for, the inherent crosstalk in biaxial goniometers, with specific relevance for applications with one dominating movement direction. Six biaxial goniometers (M110, Biometrics Ltd., Gwent, UK) were evaluated. A precision jig, for simulating pure flexion/extension angles, was constructed. Each sensor produced a consistent and specific crosstalk pattern, when tested over a ±100° range of motion. A procedure for correction for the inherent crosstalk of individual goniometer, based on polynomial adjust, is presented. The method for compensation, which reduced the root mean square error from, on average for the six goniometers, 3.7° (range 1.8–10.1°) to 0.35° (0.12–0.55°), might be required for obtaining valid goniometer measurements, e.g. of valgus/varus of the knee during gait flexion/extension movements. 相似文献
104.
Åsa Lankinen 《Journal of genetics》2009,88(2):205-215
Understanding the genetics of a polymorphic trait is important to predict its likely evolution. In Collinsia heterophylla, the upper petal lip colour can be either be white or white with a purple band, while the lower petal lip colour is invariably
purple. Because the corolla is only partly polymorphic, the polymorphism can not have evolved due to a mutation where a pigment
was lost in the entire plant, which is common in other polymorphic species. In a previous study, high frequency of the purple
band was found in populations with darker flowers, indicating possible selection for this trait. In this study, I determined
inheritance of the colour polymorphism using two populations (one with only white morph and other with both morphs). I conducted
experimental crosses within and between floral morphs to determine whether patterns of segregation in offspring conform to
single-gene predictions. Data from F1, F2, F3 and backcross progeny are consistent with a genetic model of one major locus with presence of the band being completely dominant,
as indicated in earlier studies using distantly related populations. A novel finding in this study was that the two morphs
did not show a difference in seed germination frequency or seedling survival. This trait can thus be valuable as a genetic
marker. Even though more thorough ecological data are needed to understand the potential selection pressures on upper petal
lip colour in C. heterophylla, its simple inheritance may indicate the possibility of fast evolutionary response to selective forces acting on this trait. 相似文献
105.
VESNA MILANKOV JASMINA LUDOŠKI GUNILLA STÅHLS JELENA STAMENKOVIĆ ANTE VUJIĆ 《Zoological Journal of the Linnean Society》2009,155(4):819-833
This paper examines molecular and phenotypic variability in the widely spread European hoverfly species complex Merodon avidus. Herein, based on the mitochondrial DNA (mtDNA) sequences of the cytochrome c oxidase subunit I (COI) and morphometric wing parameters, M. avidus is shown to comprise a complex of cryptic species, and one variety is redefined as a valid species: M. bicolor Gil Collado, 1930 (as var. of spinipes). The species M. bicolor, M. avidus A, and M. avidus B were clearly delimited based on their wing size. A total of 29 M. avidus and M. bicolor individuals presented 20 mtDNA haplotypes, four of which were shared by M. avidus A and M. avidus B, three were confined to M. bicolor, seven to M. avidus A, and six to M. avidus B. Sequence divergences between lineages occurring in the Balkan and in Spain ranged from 4.93 to 6.0 (uncorrected p in %) whereas divergences between M. avidus A and M. avidus B were 0.26 to 1.56. Divergence among morphologically identified individuals of M. avidus A and M. avidus B species ranged from 0.13 to 1.58, and from 0.13 to 0.52, respectively. The phenotypic substructuring and observed genetic uniqueness of populations in spatially and temporally fragmented M. avidus taxa were used to identify genetic units. The early split of two allopatric lineages, Spanish M. bicolor and Balkan M. avidus, was followed by diversification in each lineage. Present‐day morphological uniformity masks much of the genetic complexity of lineages within the M. avidus complex. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 819–833. 相似文献
106.
Martin Frenkel Carsten Külheim Hanna Johansson Jänkänpää Oskar Skogström Luca Dall'Osto Jon Ågren Roberto Bassi Thomas Moritz Jon Moen Stefan Jansson 《BMC plant biology》2009,9(1):12-16
Background
Plant performance is affected by the level of expression of PsbS, a key photoprotective protein involved in the process of feedback de-excitation (FDE), or the qE component of non-photochemical quenching, NPQ. 相似文献107.
108.
Relationships Between Tree and Soil Properties in Picea abies and Pinus sylvestris Forests in Sweden
The exchange of elements between plants and the soil in which they are growing creates reciprocal control of their element
composition. Within plants, the growth rate hypothesis from ecological stoichiometry implies a strong coupling between C,
N, and P. No similar theory exists for predicting relationships between elements in the soil or relationships between plants
and the soil. We used a data set of element concentrations in needles and humus of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) forests in Sweden to investigate the extent to which relationships between elements (C, N, P, S, K, Ca, Mg, Fe, Mn, Al)
can be observed within and between plants and soils. We found element composition to be more strongly controlled in needles
than in humus. Elements that are covalently bound were also more strongly controlled, with no apparent differences between
macro- and micronutrients. With the exception of N/C, there were surprisingly few relationships between elements in needles
and humus. We found no major differences between the two tree species studied, but investigations of additional forest types
are needed for firm conclusions. More control over element composition was exercised with respect to N than C, particularly
in needles, so it might be advantageous to express nutrient concentrations relative to N rather than on a dry weight or carbon
basis. Variations in many ecosystem variables appeared to lack ecological significance and thus an important task is to identify
the meaningful predictors. 相似文献
109.
Donald Blomqvist Angela Pauliny Mikael Larsson Lars-Åke Flodin 《BMC evolutionary biology》2010,10(1):33
Background
Inbreeding and loss of genetic diversity are expected to increase the extinction risk of small populations, but detailed tests in natural populations are scarce. We combine long-term population and fitness data with those from two types of molecular markers to examine the role of genetic effects in a declining metapopulation of southern dunlins Calidris alpina schinzii, an endangered shorebird. 相似文献110.