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131.
Pigment producing in vitro cells of Vaccinium pahalae (ohelo) were tested for their ability to survive cryopreservation and
retain pigment-production capacity after encapsulation-dehydration. Preculture of cells for 6 to 8 days in a medium containing
1.0 M sucrose was essential before dehydration. Reduction of bead water content before quenching in liquid nitrogen was highly
correlated (r = 0.94) with increased survival rate in cells after cryopreservation. Dehydration of beads for 4 h was satisfactory
for survival of cells. After quenching in liquid nitrogen, colored cells became pale, but pigment content was recovered once
cells resumed growth. After three subcultures, cells regained their maximum capacity for pigment accumulation. The percentage
of colored-to-total cell volume was not influenced by cryopreservation. Encapsulation-dehydration and cryopreservation did
not diminish the capacity of cells to produce anthocyanins and other flavonoids.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
132.
R T Damian M R Powell M L Roberts J D Clark M A Stirewalt F A Lewis 《International journal for parasitology》1985,15(3):333-344
Young, captivity-born male baboons (Papio cynocephalus) were vaccinated with γ-irradiated (500 Gy) cryopreserved Puerto Rican strain schistosomula of S. mansoni. Protection against heterologous, normal Kenyan Strain S. mansoni challenge infection was erratic and partial; and two putative correlates of immunity, reduced worm fecundity and change in worm location (anterior shift) were not observed. However, immunization of baboons with this vaccine resulted in a stimulated immune system. Both cellular and humoral anamnesis were demonstrable in vaccinated-challenged baboons. Schistosome infection-associated IgM hypergammaglobulinema was also greatly reduced in vaccinated-challenged baboons. On the other hand, IgG antibodies to adult, egg, and cercarial antigens were increased after challenge infection in preimmunized baboons. Vaccination appears to have resulted in a redirection of the immune system into anti-parasite channels, but this more specific immune response was insufficient to confer good protection against challenge infection in this experiment. The dampening effect of the vaccine on the hypergammaglobulinemia of schistosomiasis is another candidate for a possible “anti-pathogenesis” effect of irradiated schistosome larval vaccines, to be added to the reduced granuloma size already reported (Damian, Roberts, Powell, Clark, Lewis &; Stirewalt, 1984) to occur in these vaccinated baboons. Together, they could increase the potential benefit of live, irradiated vaccines for schistosomiasis. Human trials with vaccines only partially protective against challenge infections may therefore ultimately be warranted. 相似文献
133.
Tony H. H. Chen Kutty K. Kartha Lawrence V. Gusta 《Plant Cell, Tissue and Organ Culture》1985,4(2):101-109
Wheat (Triticum aestivum L. cv. Norstar) suspension cultures and regenerable calli initiated from immature embryos can be cryopreserved in liquid nitrogen temperature (–196°C) by slow freezing (0.5°C/min) in the presence of a mixture of DMSO and sucrose or sorbitol. Cold hardening or ABA treatment before cryopreservation increased the freezing resistance and improved the survival of wheat suspension culture in liquid nitrogen. Callus culture, established from immature embryos, prefrozen in 5% DMSO and 0.5M sorbitol survived liquid nitrogen storage and resumed plant regeneration after thawing. The results confirm the feasibility of long term preservation of wheat embryo callus by cryopreservation and retention of plant regeneration ability.Abbreviations ABA
Abscisic acid
- 2,4-D
2,4-Dichlorophenoxyacetic acid
- DMSO
Dimethylsulfoxide
- LN
Liquid nitrogen
- TTC
2,3,5-triphenyltetrazolium chloride
NRCC No. 23850. 相似文献
134.
A. H. Sathananthan S. C. Ng A. O. Trounson A. Bongso S. S. Ratnam J. Ho H. Mok M. N. Lee 《Molecular reproduction and development》1988,21(4):385-401
Preovulatory mouse oocytes and 2-cell embryos were frozen with dimethyl sulfoxide and propanediol by an ultrarapid method. The survival of frozen oocytes was low (33–34%) compared to that of 2-cell embryos (78–79%) with either cryoprotectant. Development to blastocysts after postthaw culture was about 7–15% for oocytes and 79–80% for the embryos. Ultrarapid freezing preserves cell structure quite well as revealed by electron microscopy, but meiotic oocytes and late 2-cell embryos undergoing mitosis showed evidence of spindle disorganization involving loss or clumping of microtubules resulting in some scattering of chromosomes. Embryos developed from frozen eggs showed clear evidence of micronuclear formation and incomplete incorporation of chromosomal material into main nuclei. These experiments confirm our observations on freezing of human oocytes and show that spindle microtubules are sensitive to freeze-thawing and that cryopreservation could cause chromosomal aberrations during early development. A cautious approach to the introduction of oocyte freezing in human in vitro fertilization (IVF) programs is advocated. 相似文献
135.
Matthew L. Skiles Katherine S. Brown William Tatz Kristen Swingle Heather L. Brown 《Cytotherapy》2018,20(4):564-575
Background
Umbilical cord (UC) tissue can be collected in a noninvasive procedure and is enriched in progenitor cells with potential therapeutic value. Mesenchymal stromal cells (MSCs) can be reliably harvested from fresh or cryopreserved UC tissue by explant outgrowth with no apparent impact on functionality. A number of stem cell banks offer cryopreservation of UC tissue, alongside cord blood, for future cell-based applications. In this setting, measuring and monitoring UC quality is critical.Materials and Methods
UC explants were evaluated using a plating and scoring system accounting for cell attachment and proliferation. Explant scores for fresh and cryopreserved-then-thawed tissue from the same UC were compared. Metabolic activity of composite UC tissue was also assayed after exposure of the tissue to conditions anticipated to affect UC quality and compared with explant scores within the same UC.Results
All fresh and cryopreserved tissues yielded MSC-like cells, and cryopreservation of the tissue did not prevent the ability to isolate MSCs by the explant method. Thawed UC tissue scores were 91% (±0.6%; P?=?0.0009) that of the fresh, biologically identical tissue. Within the same UC, explant scores correlated well to both cell yield (R2?=?0.85) and tissue metabolic activity (R2?=?0.69).Discussion
A uniform explant scoring assay can provide information about the quality of composite UC tissue. Such quantitative measurement is useful for analysis of tissue variability and process monitoring. Additionally, a metabolic assay of UC tissue health provides results that correlate well to explant scoring results. 相似文献136.
137.
138.
Vegetatively propagated material offers many advantages over seed material in forest tree breeding research and in reforestation programmes. Evidence is accumulating to suggest that using somatic embryos in forestry is a viable option. However, before somatic embryos can be used optimally in forestry, basic research aimed at increasing the number of responsive genotypes as well as the age of the primary explant is needed. This in turn requires the establishment of a basic understanding of the physiological and molecular processes that underlie the development of somatic embryos. The functions of genes and their developmental and tissue specific regulation are studied using transient and stable transformation techniques.The process of somatic embryogenesis can be divided into different steps: (1) initiation of somatic embryos from the primary explant, (2) proliferation of somatic embryos, (3) maturation of somatic embryos and (4) plant regeneration. Cortical cells in the primary explant are stimulated to go through repeated divisions so that dense nodules are formed from which somatic embryos differentiate. The first formed somatic embryos continue to proliferate and give rise to embryogenic cell lines. Embryogenic cell lines of Picea abies can be divided into two main groups A and B, based on morphology, growth pattern and secretion of proteins. Our results suggest that extracellular proteins play a crucial role in embryogenesis of Picea abies. Somatic embryos from group A can be stimulated to go through a maturation process when treated with abscisic acid. Mature somatic embryos can develop into plants.Abbreviations ABA
abscisic acid
- BA
N6-benzyladenine
- 2,4-D
dichlorophenoxy acetic acid 相似文献
139.
Cryopreservation of the milt of the northern pike 总被引:1,自引:0,他引:1
I. Babiak J. Glogowski M. J. Luczynski † D. Kucharczyk ‡ M. Luczynski § 《Journal of fish biology》1995,46(5):819-828
Seven published extenders, three thawing media and two thawing temperatures were tested in order to determine their suitability for cryopreservation of northern pike ( Esox lucius L.) sperm. Sperm motility during successive steps of cryopreservation was evaluated. Erdahl and Graham's extender with the addition of egg yolk proved to be the most efficient (maximum hatching rate of 74.5%) when semen was thawed in 120 m m NaCl solution warmed up to 30° C. No correlations between motility of sperm (diluted in extenders or diluted in extenders and then activated with thawing solution) and the subsequent hatching success were observed. The relationship between motility of thawed sperm and its fertilization ability was considerable, but correlation was not significant. Spermatozoa frozen in some extenders were frequently motile after thawing but they were not able to fertilize the eggs, this resulted in a poor hatching rate. Depending on the extender, the addition of yolk induced either positive or detrimental effects on fertilization success. 相似文献
140.
Summary The photosynthetic cell suspension culture of soybean [Glycine max (L.) Merr. cv. Corsoy] (SB-M) was successfully cryopreserved in liquid nitrogen using a preculture and controlled freezing
to −40° C (two-step) freezing method. The effective method included a preculture treatment with gradually increasing levels
of sorbitol added to the 3% sucrose already present in the medium. The cells were then placed in a cryoprotectant solution
[10% DMSO (dimethylsulfoxide) and 9.1% sorbitol, or 10% DMSO and 8% sucrose], incubated for 30 min at 0° C, cooled at a rate
of 1° C/min to −40° C, held at −40° C for 1 h, and then immersed directly into liquid nitrogen. The cells were thawed at 40°
C and then immediately placed in liquid culture medium. The cell viabilities immediately after thawing were 75% or higher
in all cases where cell growth resumed. The original growth rate and chlorophyll level of the cells was recovered within 40
to 47 d. If the sorbitol level was not high enough or the preculture period too short, growing cultures could not be recovered.
Likewise, survival was not attained with cryoprotectant mixtures consisting of 15% DMSO, 15% glycerol, and 9.1% sucrose or
15% glycerol and 8% sucrose. The successful method was reproducible, thus allowing long-term storage of this and certain other
unique photosynthetic suspension cultures in liquid nitrogen. 相似文献