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81.
82.
Hiroyuki Abe Shoko Yamashita Takeshi Satoh Hiroyoshi Hoshi 《Molecular reproduction and development》2002,61(1):57-66
In this study, the quantitative fluctuation of cytoplasmic lipid droplets (LD) and cryotolerance were investigated in bovine embryos derived from in vitro-matured (IVM) and in vitro-fertilized (IVF) oocytes developed in different culture systems using serum-free or serum-containing media. The serum-free cultures were grown using IVMD101 medium in conjunction with bovine cumulus/granulosa cell (BCGC) cocultures or IVD101 medium without BCGC cocultures, and the serum-containing cultures were grown in the presence of BCGC cocultures using HPM199 medium supplemented with 5% calf serum (HPM199 + CS). Large numbers of sudanophilic LD were present in the cytoplasm of bovine embryos from 2-cell to hatched blastocyst stages, and the number and size differed between the embryos cultured in serum-free and serum-supplemented media. In the embryos cultured in HPM199 + CS, large (2-6 microm in diameter) sudanophilic LD increased significantly from the morula to the blastocyst stages. Throughout the embryonic development, the embryos developed in serum-free cultures with and without BCGC cocultures had numerous sudanophilic LD, but most of these droplets were small (<2 microm in diameter) and large LD were less numerous than those embryos cultured in HPM199 + CS. Giant LD (>6 microm in diameter) were frequently observed in morulae and blastocysts (including early blastocysts) developed in HPM199 + CS. Electron microscopic observations demonstrated that large LD were abundant in the cytoplasm of trophoblast and embryonic (inner cell mass) cells of blastocysts cultured in HPM199 + CS. These large LD were identified as osmophilic LD, an indication that these lipid inclusions contained a significant proportion of unsaturated lipids. Many elongated mitochondria were found in embryos developed in IVMD101 and IVD101 at the morula and early blastocyst stages, whereas many of the mitochondria in the morulae developed in HPM199 + CS were of an immature form such as spherical or ovoid shape. The survival and hatching rates of embryos (morulae, early blastocysts, and blastocysts) produced in serum-free media (both IVMD101 and IVD101) after post-thaw culture were superior to those of embryos produced in serum-containing medium. These results showed that bovine embryos cultured in serum-containing medium abnormally accumulated cytoplasmic lipids into their cytoplasm and the excess accumulation of cytoplasmic LD in embryos may affect the cryotolerance of embryos. 相似文献
83.
H. Etienne F. Anthony S. Dussert D. Fernandez P. Lashermes B. Bertrand 《In vitro cellular & developmental biology. Plant》2002,38(2):129-138
Summary The important advances in coffee biotechnological techniques which have been made particularly during the last 10yr could
benefit the coffee breeder in practice and open new perspectives for the development of new varieties. The molecular phylogeny
of Coffea species has been established using DNA sequence data. The molecular markers have revealed an extremely reduced genetic diversity
in Coffea arabica L. in comparison to C. canephora. However, wild accessions collected in the Ethiopian highlands appeared to constitute a valuable gene reservoir. A complete
genetic linkage map of C. canephora was reported and additional ones are being constructed, particularly on C. arabica. The integration of Molecular Assisted Selection in coffee breeding promises to drastically increase the efficiency of breeding
programs. Economically important genes of the caffeine biosynthetic pathway or genes encoding for seed storage proteins have
been isolated. The high performance already achieved in the in vitro propagation process by somatic embryogenesis offers the possibility to mass propagate superior hybrids in different countries
of both C. arabica (selected F1 hybrids) and C. canephora (rootstock variety). Pilot productions by somatic embryogenesis currently permit preparation for commercial application.
Somaclonal variation was observed. The percentage of the off-types can vary between 3 and 10% depending on the genotype. Seed
cryopreservation enables a routine use for long-term conservation of coffee genetic resources. Transgenic plants have been
obtained for the C. arabica and C. canephora cultivated species through Agrobacterium-mediated transformation which constitutes the technique now currently used to transfer directly genes in coffee plants. 相似文献
84.
Samia S. Al-Ababneh Nabila S. Karam Rida A. Shibli 《In vitro cellular & developmental biology. Plant》2002,38(6):602-607
Summary The objective of this study was to establish a cryopreservation protocol for sour orange (Citrus aurantium L.). Cryopreservation was carried out via encapsulation-dehydration, vitrification, and encapsulation-vitrification on shoot
tips excised from in vitro cultures. Results indicated that a maximum of 83% survival and 47% regrowth of encapsulated-dehydrated and cryopreserved
shoot tips was obtained with 0.5M sucrose in the preculture medium and further dehydration for 6 h to attain 18% moisture content. Dehydration of encapsulated
shoot tips with silica gel for 2h resulted in 93% survival but only 37% regrowth of cryopreserved shoot tips. After preculturing
with 0.5M sucrose, 80% of the vitrified cryopreserved shoots survived when 2M sucrose plus 10% dimethyl sulfoxide (DMSO) was used as a cryoprotectant for 20 min at 25°C. Survival and regrowth of vitrified
cryopreserved shoot tips were 67% and 43%, respectively, when 0.4M sucrose plus 2M glycerol was used as a loading solution followed by application of 100% plant vitrification solution (PVS2) for 20 min. Increased
duration of exposure to the loading solution up to 60 min increased survival (83%) and regrowth (47%) of cryopreserved shoot
tips. With encapsulation-vitrification, dehydration with 100% PVS2 for 2 or 3 h at 0°C resulted in 50 or 57% survival and
30 or 40% regrowth, respectively, of cryopreserved shoot tips. 相似文献
85.
86.
《Cryobiology》2016,72(3):529-536
To evaluate the effects slow-freezing and vitrification on three dimensional in vitro culture of preantral follicles, ovaries of 12–14 days old female NMRI mice were isolated and randomly assigned to fresh control, slow-freezing and vitrification groups. Slow-freezing was performed using programmable freezer. Vitrification was carried out in a medium consisting of ethylene glycol (EG) and dimethyl sulphoxide (Me2SO) by needle immersion method. middle sized preantral follicles were mechanically isolated and cultured for 12 days in 0.7% sodium alginate gel. The follicles development and quantitative expression of oocyte specific genes (Bmp15, Gdf9, Fgf8) and the growth related genes (Igf1, Kit, Kit-l) were assessed after 1, 8 and 12 days of culture. Both cryopreserved groups showed reduction of follicular survival rates compared to the control group on days 8 and 12 of culture (P < 0.05). Antrum formation rates reduced in slow-freezing after 12 days of culture (P < 0.05). Evaluation of gene expression showed reduction of Bmp15, Gdf9, Fgf8, Kit and Kit-l during 12 days of culture (P < 0.05). Kit and Kit-l expression in slow-freezing group significantly reduced on day 8 of culture (p < 0.05). Igf1 expression was lower in slow-freezing group on 1st day of culture than vitrification and control groups (P < 0.05). Finally, intergroup comparison showed same expression pattern of genes after 12 days of culture. Thus, cryopreservation of mouse ovaries by both methods can preserve most developmental parameters and expression of maturation genes. However, vitrification is a better method for cryopreservation of mouse ovaries due to greater antrum formation and expression of growth related markers. 相似文献
87.
Artificial inseminations using fresh semen were successful inLemur fulvus mayottensis. Inseminations with frozen semen are in progress. 相似文献
88.
《Cryobiology》2019
While biological systems are typically studied under isobaric (constant pressure) conditions, recent reports on the bio-thermodynamics of isochoric (constant volume) systems point to their potential for subfreezing-temperature preservation of biological matter. This preliminary study, in which we report that pancreatic islets can survive multi-day preservation at high subfreezing temperatures in an isochoric chamber without osmotic cryoprotective agents (CPA), highlights the potential of isochoric cryopreservation in an application of clinical value. 相似文献
89.
《Cryobiology》2016,73(3):225-231
This study evaluates the effect of undissolved air on isochoric freezing of aqueous solutions. Isochoric freezing is concerned with freezing in a constant volume thermodynamic system. A possible advantage of the process is that it substantially reduces the percentage of ice in the system at every subzero temperature, relative to atmospheric freezing. At the pressures generated by isochoric freezing, or high pressure isobaric freezing, air cannot be considered an incompressible substance and the presence of undissolved air substantially increases the amount of ice that forms at any subfreezing temperature. This effect is measurable at air volumes as low as 1%. Therefore eliminating the undissolved air, or any separate gaseous phase, from the system is essential for retaining the properties of isochoric freezing. 相似文献
90.
《Cryobiology》2018
The rate at which lethal intracellular ice forms during sperm cryopreservation is highly dependent on the cooling protocol. The present work compares two cooling protocols for use with Iberian ibex (Capra pyrenaica) sperm by assessing the effects on the motility, viability, and size of frozen-thawed sperm cells. Ejaculates, obtained from six adult ibex males via transrectal, ultrasound-guided massage of the accessory sex glands plus electroejaculation if necessary, were cooled via either 1) Protocol 1 (decelerating cooling), involving cooling in liquid nitrogen vapor from 5 °C to −35 °C (40 °C/min), from −35 °C to −65 °C (17 °C/min), and then from −65 °C to −85 °C (3 °C/min); or 2) Protocol 2 (accelerating cooling) involving cooling in a biological freezer from 5 °C to −5 °C (4 °C/min), from −5 °C to −110 °C (25 °C/min), and then from −110 °C to −140 °C (35 °C/min). Compared to fresh ejaculates, sperm quality at thawing was found to be reduced by both protocols (p < .05), but especially by Protocol 1. Sperm head size was also significantly reduced by both protocols, although the Protocol 1 sperm heads were also significantly smaller than those of Protocol 2 sperms heads (p < .05). In fresh sperm samples, clustering analyses revealed two subpopulations of sperms with different morphometric characteristics, SP1 with larger cells, and SP2 with smaller cells. Both cooling protocols caused reduction in the proportion of SP1 cells, and an increase in the proportion of SP2 cells. In conclusion, the decelerating cooling protocol (Protocol 1) caused greater cryodamage to the sperm cells than the accelerating protocol (Protocol 2). 相似文献