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81.
Harry J. Wichers Marien P. Harkes Randy R. J. Arroo 《Plant Cell, Tissue and Organ Culture》1990,23(2):93-100
The 5-methoxypodophyllotoxin contents of plants, cell cultures and regenerated plants of Linum flavum are compared. It is demonstrated that cell cultures are able to produce amounts of 5-methoxypodophyllotoxin that are comparable to the concentration in fully differentiated plants. The production of 5-methoxy-podophyllotoxin depends on the hormonal balance of the growth medium. The use of 2,4-dichlorophenoxyacetic acid as the growth regulator is favourable for 5-methoxypodophyllotoxin production when compared to naphthylacetic acid. The 5-methoxypodophyllotoxin accumulation appears to be positively related to the internal cell volume. 相似文献
82.
83.
Hector E. Flores Paula J. Sgrignoli 《In vitro cellular & developmental biology. Plant》1991,27(3):139-142
Summary The lengthy dormancy requirement of yew seeds can be overcome with a simple in vitro method. Viable embryos were excised from
seeds ofTaxus brevifolia and four cultivars ofT. media over a range of developmental stages. Embryos were cultured in several basal media formulations (Whites’, Gamborg’s B5 and
Murashige and Skoog’s) under dark or light. After a lag period of 1 to 2 wk, embryos of both species germinated precociously.
Germination rates of up to 70% were obtained withT. media cv. Hicksi embryos. The highest rates of germination were obtained in White’s and MS media. Embryos excised from green seeds
with undeveloped arils showed the highest germination rates. As the seeds approached maturity, in vitro germination rates
of the excised embryos declined dramatically. Green seeds and seeds with developing arils could be stored at 5° C without
large loss in embryo germination. Seeds with fully developed arils could be stored frozen at −20° C for 1 wk while still allowing
about 50% of embryo germination. At least 30% of the precociously germinated embryos of both species were able to develop
into full seedlings. Our method appears to be generally applicable toTaxus spp.
This research was supported by a grant from the Hawaii Biotechnology Group, Inc. 相似文献
84.
85.
C. H. Yung E. A. Wernsman 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(3):381-384
Summary In tobacco (Nicotiana tabacum L.), anther-derived doubled haploid populations have been shown to exhibit large amounts of unexpected genetic variation and a severe depression in cured leaf yield when compared to conventionally inbred genotypes from comparable sources. A previous study had predicted that the yield depression observed in a doubled haploid population-derived from a near homozygous cultivar, NC95, might be overcome through a recurrent selection program. In the current study, progress from three cycles of full-sib family selection for improved yield in an anther-culture derived population of NC95 was measured, as well as the remaining genetic variation within the population. A design II experiment was conducted in the population following three cycles of selection. Results indicate that the NC95 yield level has been recovered in the third selection cycle population. Although most of the genetic variation in the population appears to be exhausted, the additive genetic variance among maternal half-sib families for yield is significant, and it appears that continued yield improvement can be made through recurrent selection. Significant additive-genetic variance for yield was found among maternal half-sib families but was essentially zero among the paternal half-sib families, suggesting that remaining genetic variation is not being transmitted through pollen. One possible explanation results from the phenomenon of DNA amplification that can occur during the anther culture process, and that may enable extraordinary recombinational events and reduce the viability of male gametes. 相似文献
86.
Cell membrane stability (CMS) in suspension cultures of two groundnut cultivars was studied under polyethylene glycol(PEG)-induced water stress. There was a negative relationship between PEG concentration in the medium and membrane stability measured as electrolyte leakage. The CMS values in the cell cultures correlated well with the whole plant tissue and permitted the differentiation of cultivars based on their known response to drought stress. The cell membrane stability was lower (more electrolyte leakage) when cells were grown in culture as compared to the intact plant tissue. Kadiri-3, the drought tolerant cultivar maintained higher CMS than JL-24, the drought susceptible one. With increasing PEG levels the concentration of Potassium in cultured cells declined in both cultivars. However, Kadiri-3 maintained higher K values than JL-24 accompanied with greater cell membrane stability. Total soluble sugars also increased with increasing stress in both cultivars; the increase being higher in Kadiri-3. There was no significant change in the total free amino acids but proline accumulated markedly in both varieties. However, no relationship was found between proline levels and CMS. The results demonstrated that CMS test can also be used under in vitro conditions to differentiate the drought tolerant and susceptible cultivars and the cellular K level has a positive relationship with membrane stability. 相似文献
87.
Cornelia Speth Jörg T. Epplen Ilse Oberbäumer 《In vitro cellular & developmental biology. Animal》1991,27(8):646-650
Summary Oligonucleotide fingerprinting was applied to investigate the relatedness of several cell lines that were established between
1973 and 1977 from a teratocarcinoma. We were able to distinguish cell lines derived at different times. In addition, sublines
from one cell line (PYS-2) could be discriminated by using a combination of different probes. Therefore multilocus fingerprinting
with oligonucleotides is a useful method for monitoring changes in cell lines kept in culture for many generations.
This work was supported by the Deutsche Forschungsgemeinschaft (OB 66/2-1) and by the VW-Stiftung. 相似文献
88.
David A. Smith John L. Glover Laurace E. Townsend Diane E. Maupin 《In vitro cellular & developmental biology. Animal》1991,27(12):914-920
Summary Myocardial cell culture methods are now well established for animal and fetal human tissue. We present here a method for harvesting
and culturing adult human atrial myocardiocytes. Cells are obtained from fresh atrial tissue normally discarded after being
removed to cannulate the right atrium during open heart surgery. The atrial tissue is minced and then digested using collagenase.
The single cell suspension is initially cultured in serum-containing growth medium, then transferred to defined medium, selective
for myocardial cell growth. The cells are characterized by immunoperoxidase stains and transmission electron microscopy. The
cultured cells stain positive for myoglobin, whereas control cultured fibroblasts and endothelial cells do not. Electron microscopy
shows the presence of numerous myofibrils, Z-bodies, pleomorphic mitochondria, and secretory granules. The chronological age
of the donor was an important factor in culturing the adult tissue, the younger tissue correlated with a higher success rate.
This method provides a means for in vitro study of human adult myocardial cells and provides guidelines for appropriate atrial
tissue to use. 相似文献
89.
Charles D. Laughlin 《Human nature (Hawthorne, N.Y.)》1991,2(3):171-213
Ample evidence from various quarters indicates that the perceptual-cognitive competence of the pre- and perinatal human being
is significantly greater than was once thought. Some of the evidence of this emerging picture of early competence is reviewed,
and its importance both as evidence of the biogenetic structural concept of “neurognosis” and for a theory of enculturation
is discussed. The literature of pre- and perinatal psychology, especially that of developmental neuropsychology, psychobiology,
and social psychophysiology, is incorporated, and some of the implications of these data for a theory of enculturation are
suggested.
This paper was presented at the annual meeting of the American Anthropological Association, Washington, D.C., November 1989.
Charles D. Laughlin, Professor of Anthropology at Carleton University, Ottawa, Canada, has done ethnographic fieldwork among
the So of northeastern Uganda and among Tibetan lamas in Nepal and India. He completed postdoctoral studies in neurophysiology
at the Institute of Neurological Sciences, University of Pennsylvania. He is editor of both theNeuroanthropology Network Newsletter and thePre- and Peri-Natal Psychology Journal. 相似文献
90.
《European journal of cell biology》2022,101(3):151256
An in vitro bone triple culture involving human primary osteoblasts, osteocytes and osteoclasts enables the investigation of bone healing factors, drugs or biomaterials in a model system for native bone tissue. The present study analyses the impact of Sr2+ as well as hypoxic cultivation (5% O2 content or chemically induced by Co2+) on bone cells. The three cell types were cultivated together in the presence of 100 µM Sr2+, hypoxic conditions or in the presence of 75 µM Co2+. After cultivation the cell types were separated and analysed on mRNA and protein level individually. In response to Sr2+ osteoblasts showed a downregulation of IBSP expression and a stimulation of ALP activity. Osteocyte gene marker expression of PDPN, MEPE, RANKL, OPG, osteocalcin and likewise the amount of secreted osteocalcin was reduced in the presence of Sr2+. Activity of osteoclast-specific enzymes TRAP and CAII was enhanced compared to the Sr2+ free control. Hypoxic conditions induced by both 5% O2 or a Co2+ treatment led to decreased DNA content of all bone cells and downregulated expression of osteoblast markers ALPL and IBSP as well as osteocyte markers PDPN, RANKL and OPG. In addition, Co2+ induced hypoxia decreased gene and protein expression of osteocalcin in osteocytes. In response to the Co2+ treatment, the TRAP gene expression and activity was increased. This study is the first to analyse the effects of Sr2+ or hypoxia on triple cultures with primary human bone cells. The investigated in vitro bone model might be suitable to reduce animal experiments in early stages of biomaterial and drug development. 相似文献