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601.
Transgenic tea [Camellia sinensis (L.) O. Kuntze cv. Kangra Jat] plants obtained by Agrobacterium-mediated transformation of somatic embryos 总被引:1,自引:0,他引:1
A protocol for the production of transgenic tea [Camellia sinensis (L.) O. Kuntze cv. Kangra Jat] was developed via Agrobacterium-mediated genetic transformation of somatic embryos. Two disarmed Agrobacterium tumefaciens strains, EHA 105 and LBA 4404, both carrying the binary plasmid p35SGUSINT with the nptII gene and gus-intron were evaluated as vector systems. A number of parameters were tested with respect to maximizing transformation efficiency. While pre-culture, wounding and acetosyringone treatment were inhibitory, the bacterial growth phase (optical density; OD600 = 0.6), cell density (109/ml), co-cultivation period (5 days) and pH of the co-cultivation medium (5.6) had positive effects on transformation. Following co-cultivation, globular somatic embryos were placed on multiplication medium and stressed with kanamycin (50 µg/ml). Further selection occurred in the maturation and germination medium at an elevated kanamycin level (75 µg/ml). An average of 40% transient expression was evident based on the GUS histochemical assay. Kanamycin-resistant, GUS-positive embryos were germinated, and the resulting microshoots were multiplied in vitro. Integration of the transgenes into the tea nuclear genome was confirmed by PCR analysis using nptII- and gus-specific primers and by Southern hybridization using an nptII-specific probe. The transgenic shoots were micrografted onto seed-grown rootstocks of cv. Kangra Jat and eventually hardened in a walk-in polyhouse. This is the first report on the production of transgenic tea. 相似文献
602.
By mutagenesis with N-methyl N-nitro-N-nitrosoguanidine, in two steps, a number of methionine plus threonine double auxotrophs have been isolated from a glutamate producing Arthrobacter globiformis, excreting L-lysine in good amounts. For the three potent mutants tested the medium of WHITE was adjudged to be the best. Biotin, ammonium chloride and glucose was found to be optimum at 5 μg l?1, 40 mM and 4% level, respectively. With such optimal C and N source, the strain MT 35 yielded 28.0 g lysine l?1 of medium in flask culture. 相似文献
603.
ZnS nanocrystals were prepared both in the form of mesoporous powder and thin films by one step thermal decomposition technique from a single-source procure (SSP) [Zn(SOCPh)2Lut2·H2O]. The final product was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), N2 adsorption-desorption isotherm, UV-Vis absorption spectroscopy and photoluminescence (PL) study. Structural analyses of the prepared ZnS revealed the formation of cubic crystallites with diameters around 5 and 10 nm for the thin films and powder materials, respectively. On the other hand, the powder form showed mesoporous nature (type IV isotherm) with an average pore diameter of 37.9 Å and BET specific surface area of 51.73 m2/g. 相似文献
604.
This paper presents atmospheric pollen concentrations of fifteen entomophilous trees of Eastern India. The period of anthesis and anther dehiscence varied from morning to evening. Insects and other flower visitors were found to accelerate the mechanism of pollen dispersal. The highest pollen concentration was for 267/m3 in Aegle marmelos followed in decreasing order by Eucalyptus globosus (207/m3), Cassia siamea (186/m3), C. fistula (180/m3), Delonix regia (171/m3), Butea monosperma (159/m3), Bombax ceiba (156/m3), Tectona grandis (144/m3), Terminalia arjuna (138/m3), Moringa oleifera (126/m3), Anthocephalus chinensis (114/m3), Syzygium cumini (96/m3), Dillenia indica (30/m3), Syzygium jambos (27/m3), and Kleinhovia hospita (2/m3). 相似文献
605.
L Chen R N Re O Prakash D Mondal 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1991,196(3):280-283
Because of the known capacity of angiotensin II to serve as a growth factor in multiple tissues, we elected to study the effects of renin-angiotensin system inhibition on the growth of human SH-SY5Y neuroblastoma cells. Cells were treated with captopril (0.05-5 mg/ml), enalapril, or enalaprilat (0.02-5 mg/ml) or saralasin (0.1-0.25 mg/ml). In all cases, statistically significant reductions in cell growth were seen over 5 days of culture. In additional experiments, captopril and enalaprilat significantly decreased thymidine incorporation into DNA in these cells. The administration of angiotensin II in the presence of captopril partially offset these suppressive effects. 相似文献
606.
Analysis of 3H-thymidine autoradiograms of late third instar larval salivary glands of Drosophila pseudoobscura revealed a unique example of asynchrony of replication in the autosome complement. The two autosomal arms, 2 and 3, show similar labeling pattern during the initial phases, DD to 3C, and thereafter, the chromosome 3 has fewer labeled sites than chromosome 2 until the most terminal pattern, 1D. Detailed sitewise analysis of 3H-thymidine labeling shows that while nearly 54% of the sites examined in chromosome 2 have a labeling frequency greater than 50%, only 13% of all sites in chromosome 3 have labeling frequency at that range. The number of labeled sites on chromosome 3 plotted against that on chromosome 2 shows a hyperbolic profile rather than a linear relationship. The silver grain ratio of the 2nd to 3rd increases from 1.5 to 3.1 through different stages of the cycle. These results suggest that both chromosomes start replication simultaneously but the third chromosome appears to complete the replication earlier than the second. These data open up the possibility of separate control mechanisms for the initiation and termination of DNA replication in polytene chromosomes.This paper is dedicated to the memory of the late Prof. H. D. Berendes. 相似文献
607.
Shoot buds from the saplings and the fruit bearing plants of Carica papaya L.. var. Honey Dew (papaya) initially treated with Gentamycin were cultured in modified MS media, each with a different hormonal combination, for the establishment of cultures and multiplication and rooting of plants. About 43% of explants from fruit bearing plants and 69% of those from saplings remained free of contamination and retained regeneration capacity when treated in 500 mg/l Gentamycin. For the establishment of the explants a medium containing 1 mg/l GA3 and 2 mg/l kinetin was necessary. When established buds were transferred to medium containing 1 mg/l NAA and 3 mg/l kinetin, calli were initiated at cut ends of shoot buds; multiplication started on transfer to NAA (0.1 mg/l) and BAP (0.5 mg/l) medium. Cultures have been maintained for the last twenty months without any loss in multiplication rate. Rooting was induced in medium with reduced salt concentration containing 2 mg/l IBA. Shoot elongation was induced after prolonged culture in the same rooting medium.Abbreviations MS
Murashige and Skoog, 1962
- SH
Schenk and Hildebrandt, 1972
- GA3
Gibberellic acid
- Kn
Kinetin
- NAA
Napthaleneacetic acid
- BAP
6 -Benzylaminopurine
- IBA
Indole-3-butyric acid
- IAA
Indole-3-acetic acid 相似文献
608.
609.
Chiranjit Maity Saptadip Samanta Suman K. Halder Pradeep K. Das Mohapatra Bikas R. Pati Malabendu Jana Keshab C. Mondal 《Biotechnology and Bioprocess Engineering》2011,16(2):312-319
The aim of this study was to produce two isozymes of α-amylase by immobilization of a newly isolated soil bacterium. The bacterium
was identified as Bacillus thuringiensis CKB19 on the basis of its 16S rRNA profile. Enzyme production by free cells increased linearly with cell growth up to 34
h in starch containing enriched liquid media. The active bacterial cells were immobilized in Caalginate beads, and operational
stability of the entrapped cell was optimized for amylase production. Enzyme production was optimal at an alginate concentration
of 2 g% (w/v), calcium chloride concentration of 1 M, and with 300 beads (each bead contained 2 × 107 cells)/250 mL flask. Amylase production by the immobilized cells was about 3 times higher than free cell fermentation after
34 h of incubation. It was observed that the immobilized bacterium secreted two different amylases (Am-I and Am-II) into the
culture fluid. The molecular masses of Am-I and Am-II were 59.6 and 44.7 kd, respectively, and showed optimum activity at
pH 5.0 and 9.0. Both amylases showed optimum activity at 40°C and were stable at the same temperature, with losses of only
10 and 20% (for Am I and Am II, respectively) of their original activities after 24 h of incubation. Further, both amylases
were salt tolerant (up to 4 M NaCl) and hydrolyzed raw starchy foods into glucose. All these characteristics make this enzyme
mixture suitable for use as a digestive aid and for the improvement of digestibility of animal feed ingredients. 相似文献
610.