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51.
R. Sankar P. S. Devamanoharan G. Raghupathi M. Krishnasamy C. S. Shyamala Devi 《Journal of biosciences》1987,12(3):267-271
Plumbagin was administered to rats at a concentration of 1,2,4,8 and 16 mg per kg body weight. After 24 h lipid peroxide levels
were found to decrease in subcellular fractions of liver. Plumbagin inhibited ascorbate and nicotinafde adenine dinucleotide
phosphate (reduced) dependent lipid peroxidation but was without any effect on cumene hydroperoxide dependent lipid peroxidation.
Injection of 16 mg of plumbagin per kg body weight was found to decrease liver total reduced glutathione and also fcrosomal
glucose-6-phosphatase. The results are discussed with reference to the anti- and prooxidant properties of plumbagin. 相似文献
52.
The G antigen is one of the erythrocyte membrane Rh antigens. The amount of Rh antigen present on the red blood cell is about 10(-15) g and radioactive labeling of membrane proteins is a useful method for its identification and characterization. In this paper, we compare 4 labeling techniques. Using a human monoclonal anti-Rh(G) antibody and an immunofixation technique, we located the G antigen on a polypeptide of an average molecular weight of 28,000 Da. 相似文献
53.
Voltage-dependent depolarization of bacterial membranes and artificial lipid bilayers by the peptide antibiotic nisin 总被引:24,自引:0,他引:24
The peptide antibiotic nisin is shown to disrupt valinomycin-induced potassium diffusion potentials imposed on intact cells of Staphylococcus cohnii 22. Membrane depolarization occurred rapidly at high diffusion potentials while at low potentials nisin-induced depolarization was slower suggesting that nisin requires a membrane potential for activity. This assumption was proven in experiments with planar lipid bilayers (black lipid membranes). Macroscopic conductivity measurements indicated a voltage-dependent action of nisin. The potential must have a trans-negative orientation with respect to the addition of nisin (added to the cis-side) and a sufficient magnitude (ca. -100 mV). With intact cells the threshold potential was lower (-50 to -80 mV at pH 7.5 and below -50 mV at pH 5.5). Single channel recordings resolved transient multistate pores, strongly resembling those introduced by melittin into artificial bilayers. The pores had diameters in the range of 0.2–1 nm, and lifetimes of few to several hundred milliseconds. The results indicate that nisin has to be regarded as a membrane-depolarizing agent which acts in a voltage-dependent fashion.Abbreviations BLM
Black lipid membranes
- CCCP
carbonyl cyanide m-chlorophenylhydrazone
- DOPC
dioleoyl phosphatidylcholine
- PS
phosphatidylserine
- TPP+
tetraphenylphosphonium cation 相似文献
54.
55.
The effect of tin and lead on levels of essential metals (Zn, Cu, Ca, Fe) in rabbit tissues was compared in relation to the route of administration. Animals received intraperitoneally, or per os, SnCl2 (2 mg Sn/kg) or Pb(CH3COO)2 (3.5 mg Pb/kg) every day for 5 d or for 1 mo. Copper, zinc, iron, and calcium were determined by AAS in the liver, kidneys, spleen, brain, bone marrow, and blood; lead and tin concentration were measured in the blood of animals. Tin and lead administered per os caused either no changes or the decreased concentration of endogenous metals in several tissues. The other route of administration (ip) of both metals generally contributed to the increased storage of essential elements. Blood tin levels of tin treated animals were only about less than or equal to 1/10 of blood lead concentrations of rabbits exposed to lead. 相似文献
56.
The viability ofMycobacterium leprae, maintained within 33B Schwannoma cells, was estimated in terms of incorporation of [14C] acetate into its specific phenolic glycolipid-1. This measure of viability was correlated with two other assays,viz., fluorescein diacetate/ethidium bromide staining and mouse footpad growth. Observation of a 2-fold increase in the number
of intracellularMycobacterium leprae over an experimental period of 12 days also corroborated this contention. Furthermore, on addition of anti-leprosy drugs
to these intracellularMycobacterium leprae there was significant decrease in phenolic glycolipid-1 synthesis indicative of loss of viability of the organisms. This
study also established the importance of the host cell for active bacillary metabolism, asMycobacterium leprae maintained in cell-free conditions showed no incorporation into phenolic glycolipid-1. Moreover, compromising the host’s
protein synthesis capacity with cycloheximide, also led to reduction in bacillary metabolism. As this system measures the
metabolic synthesis of a uniqueMycobacterium leprae component, it would be useful for development and screening of compounds acting against specific bacillary targets. 相似文献
57.
Cholesterol binding reserve of hyperlipemic rat serum lipoproteins in chronic ethanol administration
Chronic administration of ethanol in rats caused the reduction of serum cholesterol binding reserve. The very low density
and high density lipoproteins, main serum cholesterol binding reserves, were slightly increased with corresponding increases
in their lipid and protein components during initial stage of alcohol consumption. However, these capacities get deminished
during reversal of hyperlipemia induced by prolonged action of ethanol. This situation may be an early indicator for the initiation
of hepatic damage and a variety of secondary effects of ethanol. 相似文献
58.
A glutathione transferase from human mononuclear leukocytes with a high activity towardtrans-stilbene oxide (GT-tSBO) has been studied in liver and blood from fetus and adults and in blood from neonates. Using starch gel electrophoresis, different phenotypes of GST1 have been determined, GST1 0, GST1 1, and GST1 2. As judged from activity measurements and the fact that only those individuals who express the null allele of GST1, the GST1 0, which has a low activity towardtrans-stilbene oxide, it is concluded that the hepatic transferase GST1 is identical to GT-tSBO, as well as to hepatic transferase μ. In addition, it has been shown that the different genotypes of GST1 1 (GST1 1-1, GST1 1-0) and GST1 2 (GST1 2-2, GST1 2-0) can be separated by measuring the GT-tSBO activity in whole blood from the same individual. It is also demonstrated that GT-tSBO activity is much lower in fetal liver, approximately 10 times, compared with adult liver, while this activity seems to be unchanged in the blood from fetus and adults, as well as in neonates. 相似文献
59.
Andrew Clarke J. Cynan Ellis-Evans Mark W. Sanders Lesley J. Holmes 《Hydrobiologia》1989,172(1):183-191
The copepod Pseudoboeckella poppei (Daday) (Calanoida, Centropagidae) was sampled from Sombre and Heywood Lakes on Signy Island, Antarctica (60° S, 45° W) between January 1984 and March 1985. Sombre Lake is clear and oligotrophic with little phytoplankton and a bottom sediment low in organic content. By contrast Heywood Lake is turbid and mesotrophic; a substantial phytoplankton develops in summer and the bottom sediments are comparatively rich in organics. Both lakes freeze over for much of the year, forcing the copepods to adopt a benthic feeding strategy over winter. Adult Pseudoboeckella feed on phytoplankton when this is available, but also on detritus, diatoms and short algal filaments stirred up from the sediment. In Heywood Lake, male copepods show a smooth seasonal trend in lipid content with lipid being synthesised in early summer and utilised in late summer and winter. The summer increase in lipid content is associated with an increase in dry weight. Female lipid contents show evidence of two peaks of egg production. In Sombre Lake both male and female copepods increase in size during summer and show a wider range of lipid contents than in Heywood Lake; it is likely that this is due to the poorer winter feeding conditions which necessitate the synthesis of a much larger store of reserves during the summer. In contrast to marine calanoid copepods, lipid stores are exclusively triacylglycerol with no trace of wax ester. 相似文献
60.
Biological activities caused by far-infrared radiation 总被引:4,自引:0,他引:4
Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4–16 m) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters. 相似文献