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51.
Two highly enriched cultures containing Dehalococcoides spp. were used to study the effect of aceticlastic methanogens on reductive vinyl chloride (VC) dechlorination. In terms of aceticlastic methanogens, one culture was dominated by Methanosaeta, while the other culture was dominated by Methanosarcina, as determined by fluorescence in situ hybridization. Cultures amended with 2-bromoethanesulfonate (BES), an efficient inhibitor of methanogens, exhibited slow VC dechlorination when grown on acetate and VC. Methanogenic cultures dominated by Methanosaeta had no impact on dechlorination rates, compared to BES-amended controls. In contrast, methanogenic cultures dominated by Methanosarcina displayed up to sevenfold-higher rates of VC dechlorination than their BES-amended counterparts. Methanosarcina-dominated cultures converted a higher percentage of [2-(14)C]acetate to (14)CO(2) when concomitant VC dechlorination took place, compared to nondechlorinating controls. Respiratory indices increased from 0.12 in nondechlorinating cultures to 0.51 in actively dechlorinating cultures. During VC dechlorination, aqueous hydrogen (H(2)) concentrations dropped to 0.3 to 0.5 nM. However, upon complete VC consumption, H(2) levels increased by a factor of 10 to 100, indicating active hydrogen production from acetate oxidation. This process was thermodynamically favorable by means of the extremely low H(2) levels during dechlorination. VC degradation in nonmethanogenic cultures was not inhibited by BES but was limited by the availability of H(2) as electron donor, in cultures both with and without BES. These findings all indicate that Methanosarcina (but not Methanosaeta), while cleaving acetate to methane, simultaneously oxidizes acetate to CO(2) plus H(2), driving hydrogenotrophic dehalorespiration of VC to ethene by Dehalococcoides. 相似文献
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Dr. Frank Schneider Hans Heimann Regina Mattes Werner Lutzenberger Niels Birbaumer 《Applied psychophysiology and biofeedback》1992,17(3):203-214
Findings on depressive patients indicate that depressives have electrophysiological characteristics similar to those of schizophrenics, in that they exhibit reduced Contingent Negative Variation (CNV) amplitudes and more distinct Postimperative Negative Variations (PINVs) than normal controls. In a biofeedback experiment, 8 medicated male inpatients with the DSM III-R diagnosis of “Bipolar Disorder, Depressive,” and “Major Depression” demonstrated no impairment in the self-regulation of Slow Cortical Potentials (SCP) in comparison to schizophrenics in terms of increasing and suppressing negativity. Continuous visual SCP feedback is presented to the patient as a horizontally moving rocket in a video game format. The direction changes of the rocket represented SCP changes at each point in time, recorded by the central EEG (based on the pretrial baseline). Depressives demonstrated SCP self-regulation across 20 sessions, although with many between-and-within variations. The 8 male controls were unable to regulate their SCPs across 5 sessions. This result contradicts other findings of our laboratory on normal controls. Motivational factors and insufficient operant reinforcement (financial reward) may have facilitated this effect. 相似文献
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Molecular evolution of mitochondrial 12S RNA and cytochrome b sequences in the pantherine lineage of Felidae 总被引:4,自引:2,他引:2
DNA sequence comparisons of two mitochondrial DNA genes were used to infer
phylogenetic relationships among 17 Felidae species, notably 15 in the
previously described pantherine lineage. The polymerase chain reaction
(PCR) was used to generate sequences of 358 base pairs of the mitochondrial
12S RNA gene and 289 base pairs of the cytochrome b protein coding gene.
DNA sequences were compared within and between 17 felid and five nonfelid
carnivore species. Evolutionary trees were constructed using phenetic,
cladistic, and maximum likelihood algorithms. The combined results
suggested several phylogenetic relationships including (1) the recognition
of a recently evolved monophyletic genus Panthera consisting of Panthera
leo, P. pardus, P. onca, P. uncia, P. tigris, and Neofelis nebulosa; (2)
the recent common ancestry of Acinonyx jubatus, the African cheetah, and
Puma concolor, the American puma; and (3) two golden cat species, Profelis
temmincki and Profelis aurata, are not sister species, and the latter is
strongly associated with Caracal caracal. These data add to the growing
database of vertebrate mtDNA sequences and, given the relatively recent
divergence among the felids represented here (1-10 Myr), allow 12S and
cytochrome b sequence evolution to be addressed over a time scale different
from those addressed in most work on vertebrate mtDNA.
相似文献
57.
Monocyte activation by an oral immunomodulator (bestatin) in lymphoma patients following autologous bone marrow transplantation 总被引:2,自引:0,他引:2
Kazuhiko Ino Philip J. Bierman Michelle L. Varney Dean G. Heimann Charles A. Kuszynski Sheryl A. Walker J. E. Talmadge 《Cancer immunology, immunotherapy : CII》1996,43(4):206-212
Bestatin (ubenimex), an inhibitor of aminopeptidase, is an oral immunomodulator that binds to CD13 (aminopeptidase N) on
macrophages/monocytes. To examine its immunomodulatory effect after high-dose therapy and autologous bone marrow transplantation
(BMT), a dose-finding phase Ib trial was conducted with 30 Hodgkin’s disease and non-Hodgkin’s lymphoma patients who received
no drug (control), 10 and 30 mg (low dose), or 90 and 180 mg (high dose) of bestatin daily for 60 days following autologous
BMT. Bestatin administration was initiated when the absolute neutrophil count was greater than 250/mm3 on 2 consecutive days.
The serum neopterin levels, an indicator of monocyte/macrophage activation, increased in the high-dose group compared to the
control group (not significantly) and the low-dose group (significantly). Similarly, the colony-stimulating activity in the
sera was significantly increased in the high-dose group compared to the control and low-dose groups. We also examined the
expression of cell-surface markers on monocytes in these patients by fluorescent cytometry analysis. There was no significant
difference either in the frequency or absolute number of monocytes (CD14+) among the three groups at any time. However, a significant increase in the frequency of CD16(FcgRIII)-positive monocytes
(a marker of activation) was observed in the high-dose group compared to controls from day 14 to day 60 after the start of
bestatin administration. Further, the frequency of HLA-DR+ monocytes (another marker of activation) was significantly increased in the high-dose group. These results indicate that
bestatin at higher doses (90 and 180 mg daily), but not lower doses, activates macrophages/monocytes, as demonstrated by phenotypic
marker (HLA-DR and CD16) up-regulation, and this provides augmentation of neopterin and colony-stimulating activity in the
serum of patients following autologous BMT.
Received: 24 June 1996 / Accepted 13 September 1996 相似文献
58.
Sea urchin Hox genes: insights into the ancestral Hox cluster 总被引:3,自引:0,他引:3
We describe the Hox cluster in the radially symmetric sea urchin and
compare our findings to what is known from clusters in bilaterally
symmetric animals. Several Hox genes from the direct-developing sea urchin
Heliocidaris erythrogramma are described. CHEF gel analysis shows that the
Hox genes are clustered on a < or = 300 kilobase (kb) fragment of DNA,
and only a single cluster is present, as in lower chordates and other
nonvertebrate metazoans. Phylogenetic analyses of sea urchin, amphioxus,
Drosophila, and selected vertebrate Hox genes confirm that the H.
erythrogramma genes, and others previously cloned from other sea urchins,
belong to anterior, central, and posterior groups. Despite their radial
body plan and lack of cephalization, echinoderms retain at least one of the
anterior group Hox genes, an orthologue of Hox3. The structure of the
echinoderm Hox cluster suggests that the ancestral deuterostome had a Hox
cluster more similar to the current chordate cluster than was expected Sea
urchins have at least three Abd-B type genes, suggesting that Abd-B
expansion began before the radiation of deuterostomes.
相似文献
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