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41.
Finely ground ore material (90%–200 mesh) was subjected to acid microbiological leaching in 20% and 30% (wt/vol) suspensions. The rate of aeration was maintained at 2 and 4 1/min · 1. After the onset of the microbiological phase of leaching, the solubilization of iron was initially rapid but was succeeded by Fe(III) precipitation. Major differences were apparent between inoculated and uninoculated suspensions for each metal analyzed (Fe, Al, Co, Cu, Ni, Zn). The sulfur balance in leach residues indicated elevated levels of elemental S and sulfate in the inoculated systems. 相似文献
42.
Human alveolar macrophage fibronectin: synthesis, secretion, and ultrastructural localization during gelatin-coated latex particle binding 总被引:14,自引:4,他引:10
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Human pulmonary alveolar macrophages synthesized and secreted several characteristic high molecular weight proteins for at least 7 d in vitro. Immunoprecipitates of medium and cell lysates from metabolically labeled cultures with specific anti-human plasma fibronectin IgG contained one major labeled polypeptide of molecular weight 440,000 (unreduced) or 220,000 (reduced). An identical polypeptide in conditioned medium from radiolabeled macrophages bound specifically to gelatin-Sepharose, demonstrating that alveolar macrophages synthesized and secreted a molecule immunologically and functionally similar to fibronectin. Fibronectin was the major newly synthesized and secreted polypeptide of freshly harvested alveolar macrophages. Pulse-chase experiments revealed that newly synthesized fibronectin was rapidly secreted into medium, approximately 50 percent appearing by 1 h and 80 percent by 8 h. Immunoperoxidase staining using antifibronectin F(ab’)(2)-peroxidase conjugates revealed the majority of immunoreactive fibronectin to be intracellular, localized to endoplasmic reticulum and Golgi apparatus. No extracellular matrix fibronectin was visualized, and cell surface staining was rarely seen, usually appearing only at sites where cells were closely apposed and not at sites of macrophage-substrate attachment. Similar immunostaining of fibroblast cultures revealed cell surface-associated fibrillar fibronectin. Ultrastructural localization of fibronectin during binding and phagocytosis of gelatin-coated and plain latex particles revealed fibronectin only on gelatin-latex beads and at their cell binding sites. Neigher plain latex beads nor their cell membrane binding sites stained for fibronectin. These results demonstrate that fibronectin is a major product of human alveolar macrophages, is rapidly secreted, and is localized at cell membrane binding sites for gelatin-coated particles. In view of the known binding properties of fibronectin, it may serve as an endogenous opsonic factor promoting the binding of staphylococcus, denatured collagen, fibrin, or other macromolecules to macrophages in the lower respiratory tract. 相似文献
43.
On the phospholipids of Bacillus megaterium 总被引:12,自引:0,他引:12
44.
45.
Phylogenetic screening of the human genome: identification of differentially hybridizing repetitive sequence families 总被引:1,自引:0,他引:1
The phi-screen, a method of phylogenetic screening, can be employed to
detect repetitive sequence families that differentially hybridize between
closely related species. Such differences may involve sequence divergence
or variations in copy number, including total presence versus absence of a
family of repeated DNA. We present the results of a phi-screen comparing
the human genome to that of the prosimian, Galago crassicaudatus. Three
human repetitive families that are divergent or not present in galago have
been detected. One of these families is described in detail; it is similar
among the anthropoids but is present in a lower copy number and/or
divergent form in prosimians. The family is clearly related to the
transposon-like human element (THE) described by Paulson et al. (1985).
THEs have long terminal repeats reminiscent of retroviruses but are unique
in that they have no sequence similarity to known mammalian retroviruses.
The sequence of a solo long terminal repeat, found unassociated with THE
internal sequence, is presented. This family member, THE p2, is bordered by
a 5-bp target-site repeat and is interrupted by the insertion of an Alu
element. A solo THE element sequenced by Wiginton et al. (1986) contains an
insertion of Alu at precisely the same position as does THE p2.
相似文献
46.
The alcohol dehydrogenase (Adh) region from five planitibia subgroup
species of Hawaiian picture-wing Drosophila has been cloned. A total of 15
kb of DNA in and around the Adh gene has been compared among the five
species. Genetic distances were calculated to determine evolutionary
relationships. These distances agree with previous distances determined by
protein polymorphism and DNA hybridization techniques and can be
interpreted in terms of specific island colonization and speciation
(founder) events over the past 5 Myr. Examination of the restriction maps
of the cloned Adh region from the five species shows many instances of
small deletions, insertion of a transposable element in D. heteroneura, and
the existence of a highly variable region on the 3' side of the Adh gene.
Clustering relationships and rates of DNA change are calculated and
compared with the relationship found for other species of Drosophila.
相似文献
47.
Biological ferric iron production was combined with ferric sulphate leaching of chalcopyrite concentrate and the effects of pH, Fe3+, temperature and solids concentration on the leaching were studied. The copper leaching rates were similar at pH of 1.0-1.8 and in the presence of 7-90 g L-1 Fe3+ despite massive iron precipitation with 90 g L-1 Fe3+. Increase of the leaching temperature from 50 degrees C to 86 degrees C and solids concentration from 1% to 10% increased the copper leaching rate. Increase in solids concentration from 1% to 10% decreased the copper yields from 80% to 40%. Stepwise addition of ferric iron did not improve the copper yields. CuFeS2, Ag and Cu1.96S potentials indicated the formation of a passivating layer, which consisted of jarosite and sulphur precipitates and which was responsible for the decreased leaching rates. 相似文献
48.
Dogan Karadag Annukka E. Mkinen Elena Efimova Jaakko A. Puhakka 《Bioresource technology》2009,100(23):5790-5795
Batch experiments were conducted to investigate the thermophilic biohydrogen production using an enrichment culture from a Turkish hot spring. Following the enrichment, the culture was heat treated at 100 °C for 10 min to select for spore-forming bacteria. H2 production was accompanied by production of acetate, butyrate, lactate and ethanol. H2 production was associated by acetate–butyrate type fermentation while accumulation of lactate and ethanol negatively affected the H2 yield. H2 production was highest in the temperature range from 49.6 to 54.8 °C and optimum values for initial pH and concentrations of iron, yeast extract and glucose were 6.5, 40 mg/l, 4–13.5 g/l, respectively. PCR–DGGE profiling showed that the heat treated culture consisted of species closely affiliated to genus Thermoanaerobacterium. 相似文献
49.
Annukka E. Mäkinen Anna H. Kaksonen Jaakko A. Puhakka 《Extremophiles : life under extreme conditions》2009,13(3):505-510
A thermophilic, rod-shaped, motile, Gram-positive, spore-forming bacterium strain 70BT was isolated from a geothermally active underground mine in Japan. The temperature and pH range for growth was 50–81°C (optimum
71°C) and 6.2–9.8 (optimum pH 7–7.5), respectively. Growth occurred in the presence 0–2% NaCl (optimum 1% NaCl). Strain 70BT could utilize glucose, fructose, mannose, mannitol, pyruvate, cellobiose and tryptone as substrates. Thiosulfate was used
as electron acceptor. Major whole-cell fatty acids were iso-C15:0, C16:0 DMA (dimethyl acetal), C16:0 and anteiso-C15:0. The G+C mol% of the DNA was 44.2%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the closest relatives
of strain 70BT were Thermosediminibacter oceani DSM 16646T (94% similarity) and Thermosediminibacter litoriperuensis DSM 16647 (93% similarity). The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain 70BT represents a novel species in a new genus, for which the name Thermovorax subterraneus gen. nov., sp. nov. is proposed. The type strain of Thermovorax subterraneus is 70BT (=DSM 21563 = JCM 15541). 相似文献
50.
Wagner Vital Gustavo Lazzaro Rezende Leonardo Abreu Jorge Moraes Francisco JA Lemos Itabajara da Silva VazJr Carlos Logullo 《BMC developmental biology》2010,10(1):25