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11.
Ronald S. Kaplan June A. Mayor Renee Blackwell Glenn L. Wilson Stephen W. Schaffer 《Molecular and cellular biochemistry》1991,107(1):79-86
The effect of non-insulin-dependent diabetes mellitus (i.e., NIDDM; type 2 diabetes) on the levels of functional mitochondrial anion transport proteins has been determined utilizing
a chemically-induced neonatal model of NIDDM. We hypothesized that moderate insulin deficiency exacerbated by the insulin
resistance, which is characteristic of NIDDM, would cause changes in mitochondrial anion transporter function that were similar
to those we have previously shown to occur in insulin-dependent diabetes mellitus (i.e., IDDM; type 1 diabetes) (Arch. Biochem. Biophys. 280: 181–191, 1990). Our experimental approach consisted of the extraction
of the pyruvate, dicarboxylate and citrate transport proteins from the mitochondrial inner membrane with Triton X-114 using
rat liver mitoplasts (prepared from diabetic and control animals) as the starting material, followed by the functional reconstitution
of each transporter in a proteoliposomal system. This strategy permitted the quantification of the functional levels of these
three transporters in the absence of the complications that arise when such measurements are carried out with intact mitochondria
(or mitoplasts). We found that experimental NIDDM did not cause significant changes in the extractable and reconstitutable
specific (and total) transport activities of the pyruvate, dicarboxylate, and citrate transporters. These results are in marked
contrast to our previous findings obtained using rats with IDDM and negated our hypothesis. The present results, in combination
with our earlier findings, allow us to conclude that insulin plays an important role in the regulation of mitochondrial anion
transporter function. Accordingly, in this model of NIDDM, where the level of insulin is not profoundly deficient, transporter
function is unaltered, whereas in IDDM, where a profound insulinopenia exists, transporter function is altered. Furthermore,
the present studies suggest that in the neonatal model of NIDDM the three mitochondrial transporters investigated are neither
affected by, nor are they the sites of the well documented hepatic post-receptor insulin resistance which is characteristic
of this disease. 相似文献
12.
Alfredo Munoz-Rivas Charles A. Specht Bruce J. Drummond Eunice Froeliger Charles P. Novotny Robert C. Ullrich 《Molecular & general genetics : MGG》1986,205(1):103-106
Summary Protoplasts of aSchizophyllum commune tryptophan auxotroph (trp1), deficient in indole-3-glycerol phosphate synthetase (IGPS), were transformed to trp+ with plasmid DNA containing the SchizophyllumTRP1 sequence. Efficiencies up to 30 transformants per microgram of plasmid DNA were obtained. Southern blots reveal that the
transforming DNA is integrated in chromosomal DNA. The trp+ phenotype of transformants is stable in meiosis and mitosis. Transformants possess IGPS activity comparable to wild-type
cells. 相似文献
13.
Summary A new method of functional morphological analysis is presented. Combining stereophotogrammetry with the finite element technique, a new approach, permits a three-dimensional numerical stress analysis of arbitrarily shaped bodies to be performed. The stereophotogrammetric method which originated for three-dimensional calculations in the study of surfaces in land surveying is well suited for the determination of the nodal co-ordinates required for the finite element method, an engineering technique developed for behavioural analysis of solids and fluids responding to external forces. This approach was tested in a study of the functional morphology of the bill of an African wading bird, the shoebill Balaeniceps rex. A few findings of that study are given here in order to demonstrate the method. Advantages of the finite element method compared with other techniques for stress analysis of anatomical structures are also discussed. The method presents exciting possibilities for predicting displacement and stress responses more accurately and in much greater detail. The scope of this powerful computerized stress analysis technique is greatly enhanced with the introduction of stereophotogrammetry for determining the three-dimensional co-ordinates of complex anatomical structures. With the finite element method, the properties of the bone structure can be modelled as they occur in the life of the animal. This is not possible with physical models. Furthermore, rare specimens can be analysed non-destructively. 相似文献
14.
Biophysical and Biochemical Studies on Rhinovirus and Poliovirus II. Chemical and Hydrodynamic Analysis of the Rhinovirion 总被引:2,自引:2,他引:0
Chemical analysis of rhinovirus 14 revealed a ribonucleic acid (RNA) content of 29.8% and a high adenylic acid content (35%). A partial specific volume of 0.682 cm3/g was obtained for the rhinovirion. Rhinovirus and poliovirus had identical sedimentation coefficients of 158S. A diffusion coefficient of 1.71 × 10−7 cm2/sec was consistent with a hydrated diameter of 25 nm for the rhinovirion. The calculated molecular weights of the rhinovirion and its genome were 7.1 × 106 and 2.1 × 106 daltons, respectively. Sedimentation analysis of infectious RNA confirmed the similarity of the molecular size of the poliovirus and rhinovirus genomes. 相似文献
15.
16.
Staining patterns suggest that in the adeno-associated satellite virion there exist quasi single-stranded regions which are renatured after extraction to exhibit double strandedness. 相似文献
17.
Summary The pollinium of Epidendrum scutella, both in the anther and on the stigma, was examined with the electron microscope. The sporoderm of the outer tetrads has a sexine and an intine while that of the inner tetrads lacks a sexine, and an intine is formed only after the pollinium is on the stigma. A fibrous wall layer apparently holds the tetrads together. The cytoplasm is filled with plastids, mitochondria, polysomes, vacuoles and vesicles of various sizes, and endoplasmic reticulum (ER) with narrow cisternae. The vegetative nucleus is oval in form and contains a large nucleolus. The generative nucleus is deeply lobed and contains a well-developed nucleolus. The generative cytoplasm lacks both plastids and mitochondria and has little ER. Dictyosomes are present as well as assorted vesicles. A pocket is present between the plasma membrane of the generative cell and the wall; it contains assorted membranes and ribosome-like particles. After the pollen is on the stigma the wall surrounding the generative cell begins to disappear and gaps develop in it.This investigation was carried out during the tenure of a research fellowship from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.Research supported by grants from National Science Foundation (GB-3460) and the Miller Institute for Basis Science at the University of California, Berkeley. The authors would like to thank Miss Mary Ashton for her assistance in the research. 相似文献
18.
Physical Assay and Growth Cycle Studies of a Defective Adeno-Satellite Virus 总被引:29,自引:19,他引:10
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Wade P. Parks Joseph L. Melnick Robert Rongey Heather D. Mayor 《Journal of virology》1967,1(1):171-180
Electron microscopic particle counting of the defective adeno-satellite virus (ASV), by use of pseudoreplication and negative staining with phosphotungstic acid, was shown to be a reproducible quantitative assay procedure. Particles of satellite type 4 that were counted in fluids from infected cultures had the same morphology as particles that banded at a buoyant density of 1.43 g/cc in cesium chloride. Other satellite virus serotypes examined in the same manner had a buoyant density of 1.37 to 1.38 g/cc. A comparison of satellite titers obtained by complement fixation and by particle counting demonstrated that an increase in satellite particles resulted in a corresponding increase in CF titers; however, electron microscopy was at least 10 times more sensitive than complement fixation for detecting satellite virus. Growth cycle studies of satellite virus in cells co-infected with adenovirus, as assayed by particle counting, indicated that the kinetics of satellite virus production closely followed the kinetics of its helper adenovirus production, with an eclipse period of 12 to 16 hr. The eclipse period of the satellite remained the same when cultures were preinfected with satellite 24 hr prior to adenovirus inoculation. However, when cultures were infected with adenovirus 12 hr before satellite virus, the eclipse period of the satellite was shortened to between 4 and 6 hr. Thus, satellite virus replication seems dependent upon a relatively late event in the adenovirus replication cycle. When cells were co-infected with adenovirus and its defective satellite, the yield of adenovirus was markedly reduced from that obtained in cells singly infected with adenovirus. 相似文献
19.
Hydroperoxide inactivation of enzymes within spores of Bacillus megaterium ATCC19213 总被引:2,自引:0,他引:2
Abstract Hydroperoxide inactivation of the protoplast enzymes enolase, aldolase and glucose-6-phosphate dehydrogenase in intact spores of Bacillus megaterium ATCC19213 was assessed by first treating the cells with lethal levels of H2 O2 , then germinating them in the presence of chloramphenicol prior to permeabilization and enzyme assays. Glucose-6-phosphate dehydrogenase proved to be more sensitive to H2 O2 than enolase or aldolase, in agreement with findings for isolated enzymes. Average D values (time for 90% inactivation) for spores treated with 0.50% H2 O2 were 173 min for enolase, 67 min for aldolase and 32 min for glucose-6-phosphate dehydrogenase, compared with a D value of 34 min for spore killing. H2 O2 killing of spores was found to be conditional in that recoveries of survivors were greater on complex medium than on minimal medium. Overall, it appeared that oxidative inactivation of enzymes may be important for hydroperoxide killing of spores. 相似文献
20.
Extremophile research in the European Union: from fundamental aspects to industrial expectations 总被引:5,自引:0,他引:5
Alfredo Aguilar 《FEMS microbiology reviews》1996,18(2-3):89-92