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131.
Sodium lactate delays toxin production by Clostridium botulinum in cook-in-bag turkey products 总被引:2,自引:0,他引:2
Comminuted raw turkey, containing 1.4% sodium chloride, 0.3% sodium phosphate, and 0 (control), 2.0, 2.5, 3.0, or 3.5% sodium lactate, was inoculated with a 10-strain mixture of proteolytic type A and B Clostridium botulinum spores. The inoculated turkey was vacuum packaged and cooked by immersion in heated water to an internal temperature of 71.1 degrees C. Samples were incubated at 27 degrees C for up to 10 days. Five samples per treatment were examined for botulinal toxin at specific intervals. Sodium lactate exhibited an antibotulinal effect which was concentration dependent. Processed turkey containing 0, 2.0, 2.5, 3.0, or 3.5% sodium lactate was toxic after 3, 4 to 5, 4 to 6, 7 or 7 to 8 days, respectively. Subsequent studies with a broth medium revealed that lactate, not the sodium ion, was the principal factor in delaying botulinal-toxin formation. 相似文献
132.
S Notermans T Chakraborty M Leimeister-W?chter J Dufrenne K J Heuvelman H Maas W Jansen K Wernars P Guinee 《Applied and environmental microbiology》1989,55(4):902-906
A total of 284 strains of Listeria, including all known serovars and biovars together with Listeria grayi and Listeria murrayi, were biotyped and serotyped. Biotyping and serotyping could be done in 2 days. A gene probe encoding a delayed hypersensitivity factor (DTH) was used in the detection of pathogenic biotypes and serotypes of the tested strains. The gene was found in all 117 tested Listeria monocytogenes strains of serogroups 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4c, 4d, 4e, 4ab, and 7. It was also present in Listeria ivanovii. Of 78 L. monocytogenes strains of serogroup 4b, 77 strains contained the gene, whereas it was absent in all 10 tested L. monocytogenes strains of serogroup 4a. Furthermore, the gene was absent in Listeria seeligeri, L. grayi, L. murrayi, and L. innocua of serogroups 3c, 4b, and 6a and in L. welshimeri of serogroups 1/2b, 3b, 6a, and 6b. Since L. monocytogenes and L. ivanovii are the only two biotypes of the genus Listeria considered pathogens, the data obtained indicate that the DNA probe tested may be a useful tool in the detection of virulent Listeria isolates in clinical, environmental, and food samples. 相似文献
133.
Mechanism and optimized conditions for PEG mediated DNA transfection into plant protoplasts 总被引:3,自引:0,他引:3
Experimental conditions influencing DNA uptake efficiency by maize protoplasts in polyethyleneglycol (PEG) mediated transfection experiments have been studied systematically. The data provide evidence that the extracellular DNA is precipitated efficiently by combined action of PEG together with divalent cations and DNA is taken up by the plant protoplasts in the precipitated form. The particle size is strongly effected by the pH of the PEG solution. At optimal pH 6– 6.5 a very fine and homogenous precipitate forms in presence of Ca2+ and Mg2+ ions and is efficiently incorporated by maize and rice protoplasts.Abbreviations CAT
Chloramphenicolacetyl transferase
- DAPI
4,6-Diamidino-2-Phenylindole
- HEPES
N-2-Hydroxyethylpiperazine-N-2- ethanesulfonic acid
- MES
2(N-Morpholino)ethanesul fonic acid
- PEG
Polyethyleneglycol
- SW
seawater 相似文献
134.
The presumed blood-brain barrier to 6-OH-DA was studied in 25–36 day old rats with high (30 mg/kg) and low (0.14 mg/kg) dose intravenous 6-OH-DA-1-14C. From measurements of radioactivity in heart, brain and plasma, the authors conclude that a blood-brain barrier to 6-OH-DA exists in this species. 相似文献
135.
Comparison of the resA1 and polA1 Mutations in Isogenic Strains of Escherichia coli K-12 总被引:1,自引:0,他引:1 下载免费PDF全文
Barry W. Glickman Cornelis A. Van Sluis Gerda Van Der Maas Arthur Rrsch 《Journal of bacteriology》1973,114(3):951-955
Strains carrying either the polA1 or resA1 mutation are deficient in DNA polymerase I, and the polA1 and resA1 mutations do not complement in merozygotes. The effect of these mutations in otherwise identical genetic backgrounds was studied: after ultraviolet irradiation both strains degrade their DNA more rapidly and more extensively than the wild-type strains. However, after X-ray irradiation the resA1 strain shows little DNA breakdown and repairs its single-strand breaks. In contrast, the polA1 strain degrades its DNA extensively, and single-strand breaks are not repaired. Moreover, the resA1 strain is capable of supporting the growth of a red(-) bacteriophage lambda, whereas the polA1 strain is not. 相似文献
136.
Chromosomal Integration of F′ Factors in Recombination-Deficient Hfr Strains of Escherichia coli 下载免费PDF全文
In matings between F′ donors and recombination-deficient Hfr recipients, we isolated progeny which transferred both episomal markers and Hfr markers early and with high frequency. A number of these progeny had two integrated sex factors. Investigation of these double Hfr strains showed that the F′ nearly always integrated in a homologous region of the chromosome. In any particular mating system integration was specific as to location and direction of chromosome transfer. 相似文献
137.
Halicyclops korodiensis Onabamiro was recorded in plankton samples of the brackish waters of the Warri River, Nigeria, West Africa. It is redescribed
and figured. 相似文献
138.
The analysis of traumatic fractures can provide valuable information concerning the affects of sociopolitical factors upon
the health of prehistoric populations. However, such information can only be acquired by implementing a quantitative demographic
approach. The present research applies such a method to longbone fractures in two medieval Christian populations excavated
from ancient Nubia. Long-bones of two hundred and eighteen individuals from an early (550 to 750 A.D.) Christian cemetery
and 188 individuals from a late (750 to 1450 A.D.) Christian cemetery were examined for evidence of traumatic fracture. Analysis
included a determination of fracture rates, age and sex related fracture patterns, and rate of fracture per years at risk.
The results of this study indicate that the majority of fractures in both cemeteries were likely caused by accidental falls.
Fractures resulting from direct (possibly interpersonal) violence were found in both samples, though at a higher frequency
in the early Christian population (27% versus 16%). Middle-aged adults (particularly males) of the early cemetery exhibited
a higher than expected risk to fractures indicating an activity related cause of injury. In contrast, the late Christian population
showed a marked increase in fractures among both children and the elderly. This distribution may reflect changes in health
and residential architecture which occurred during the late Christian period. 相似文献
139.
An evaluation of plant-borne factors promoting the solubilization of alkaline rock phosphates 总被引:4,自引:0,他引:4
T. Bekele B. J. Cino P. A. I. Ehlert A. A. Van Der Maas A. Van Diest 《Plant and Soil》1983,75(3):361-378
Summary Four experiments are described in which the uptake patterns of various crop species were shown to enhance the solubilization
of alkaline rock phosphates. In most cases, such enhancements resulted from soil acidification brought about by the alkaline
uptake patterns. In one case, the enhancement may have stemmed primarily from a high Ca-uptake rate, which might be responsible
for a shift in mass-action equilibria favoring the solubilization of rock phosphates. High uptake of Ca is expected to serve
two purposes: 1. it acts in creating alkaline uptake patterns causing a decline in soil pH, and 2. it promotes a shift in
mass-action equilibria. 相似文献
140.
James F. Leckman James W. Maas D. Eugene Redmond George R. Heninger 《Life sciences》1980,26(25):2179-2185
Repeated (N=15) administration of clonidine (0,1,5 μg/kg,p.o.) to three normotensive male subjects resulted in significant decreases in plasma free 3-methoxy-4-hydroxyphenethyleneglycol (MHPG) at three hours for both the 1 μg/kg dose (p < .05) and the 5 μg/kg dose (p < .01) when compared to concentrations following placebo. The mean decrement in plasma free MHPG following a 5 μg/kg dose was 36%. Systolic blood pressure fell a mean of 17 mmHg after 1 μg/kg and 37 mmHg after 5 μg/kg of clonidine. The application of a clonidine challenge test to assess noradrenergic receptor sensitivity is discussed. 相似文献