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191.
Senear DF Tretyachenko-Ladokhina V Opel ML Aeling KA Hatfield GW Franklin LM Darlington RC Alexander Ross JB 《Nucleic acids research》2007,35(6):1761-1772
E. coli Integration host factor (IHF) condenses the bacterial nucleoid by wrapping DNA. Previously, we showed that DNA flexibility compensates for structural characteristics of the four consensus recognition elements associated with specific binding (Aeling et al., J. Biol. Chem. 281, 39236–39248, 2006). If elements are missing, high-affinity binding occurs only if DNA deformation energy is low. In contrast, if all elements are present, net binding energy is unaffected by deformation energy. We tested two hypotheses for this observation: in complexes containing all elements, (1) stiff DNA sequences are less bent upon binding IHF than flexible ones; or (2) DNA sequences with differing flexibility have interactions with IHF that compensate for unfavorable deformation energy. Time-resolved Förster resonance energy transfer (FRET) shows that global topologies are indistinguishable for three complexes with oligonucleotides of different flexibility. However, pressure perturbation shows that the volume change upon binding is smaller with increasing flexibility. We interpret these results in the context of Record and coworker's model for IHF binding (J. Mol. Biol. 310, 379–401, 2001). We propose that the volume changes reflect differences in hydration that arise from structural variation at IHF–DNA interfaces while the resulting energetic compensation maintains the same net binding energy. 相似文献
192.
Human prostate glandular epithelial cells have the unique capability of accumulating high levels of zinc. This is essential to inhibit m-aconitase activity so that citrate can accumulate for secretion into prostatic fluid, which is a major function of the prostate gland. As a result, the Krebs cycle is truncated with the consequence of the lost ATP production that would result from citrate oxidation. The cellular accumulation of zinc also inhibits mitochondrial terminal oxidation and respiration. In addition to these metabolic effects, zinc accumulation exhibits anti-proliferative effects via its induction of mitochondrial apoptogenesis. Zinc accumulation also inhibits the invasive/migration activities in malignant prostate cells. The anti-proliferative effects and the effects on invasion and migration occur through zinc activation of specific intracellular signaling pathways. Consequently, these effects impose anti-tumor actions by zinc. The ability of prostate cells to accumulate zinc is due to the expression and activity of the zinc uptake transporter, ZIP1. To avoid the anti-tumor effects of zinc, in prostate cancer the malignant prostate cells exhibit a silencing of ZIP1 gene expression accompanied by a depletion of cellular zinc. Therefore we regard ZIP1 as a tumor suppressor gene in prostate cancer. In addition to prostate cells, similar tumor suppressor effects of zinc have been identified in several other types of tumors. 相似文献
193.
Glaros AG Kim-Weroha N Lausten L Franklin KL 《Applied psychophysiology and biofeedback》2007,32(3-4):149-154
This study tested the hypothesis that a habit reversal program emphasizing awareness and reduction of masticatory muscle activity
would significantly reduce pain in patients diagnosed with chronic temporomandibular disorder (TMD) and would be a competitive
alternative to a behaviorally-modified dental intervention. Eight individuals diagnosed with TMD were randomly assigned to
a splint therapy or habit reversal group. Patients in the splint group received an interocclusal appliance (splint) fabricated
from acrylic and were instructed to wear the splint day and night up to a maximum of 20 h per day. Patients in the habit reversal
group were given a pager and instructed to check tooth position and masticatory muscle tension when paged. Paging occurred
approximately once every 2 h during the day, but not at night. Both groups were instructed to avoid tooth contact and relax
the masticatory muscles during the 4 weeks of active treatment. Outcome data were collected at 1 month and 1 year post-treatment
intervals. Pain decreased significantly for both groups and did not differ between groups. Habit reversal may be as effective
as a behaviorally-modified splint therapy for TMD-related pain. 相似文献
194.
Pseudomonas aeruginosa is intrinsically resistant to the hydrophobic biocide triclosan, and yet it can be sensitized to low concentrations by permeabilization of the outer membrane using compound 48/80. A selective plating assay revealed that compound 48/80-permeabilized YM64, a triclosan-recognizing efflux pump-deficient variant, was unable to initiate growth on a medium containing triclosan. Macrobroth dilution assay data revealed that treatment with compound 48/80 synergistically decreased minimal inhibitory concentrations of the hydrophobic antibacterial agents rifamycin SV and chloramphenicol for all cell envelope variant strains examined. A low concentration of triclosan exerted a transient bactericidal effect on permeabilized wild-type strain PAO1, after which exponential growth resumed within 4 h. Permeabilized strain YM64 was unable to overcome the inhibition; yet, both strains remained susceptible to chloramphenicol for as long as 6 h, thereby suggesting that the outer membrane remained permeable to nonpolar compounds. These data support the notion that the transitory nature of compound 48/80 sensitization to triclosan in P. aeruginosa does not involve obviation of the hydrophobic diffusion pathway through the outer membrane. The inability of strain YM64 to overcome the synergistic effect of compound 48/80 and triclosan strongly suggests that triclosan-recognizing efflux pumps are involved in maintaining viability in wild-type cells whose outer membranes are otherwise compromised. 相似文献
195.
The spotted owl (Strix occidentalis) is a threatened species in many areas of its western North American range. Concomitant with its decline has been a rapid
invasion of its range and habitat by barred owls (Strix varia), a native species that was restricted, until relatively recently, to eastern North America. We assess the theoretical potential
for negative interactions between these two owls by examining size dimorphism and ecological relationships within various
owl assemblages throughout the world. We then review the anecdotal, natural history, modeling, and experimental evidence that
suggest barred owls may negatively affect spotted owls with at least a potential for the competitive exclusion of spotted
owls by barred owls throughout all or part of the former’2019;s range. While it is widely accepted that barred owls are either
causing or exacerbating declines of spotted owl populations, there are confounding factors, such as habitat loss and bad weather
that also may contribute to declines of spotted owls. Both theory and empirical information suggest that barred owls are likely
to have negative effects on spotted owl range and density, but the degree of the impact is not predictable. There is a conservation
conundrum here, in that the barred owl is a native species that has expanded its range westwards, either naturally or with
a degree of human facilitation, and now constitutes a major threat to the viability of another native species, the threatened
spotted owl. We propose that only through carefully designed experiments involving removal of barred owls will we be able
to determine if recent declines in spotted owl populations are caused by barred owls or by other factors. It is rare in conservation
science that replicate study areas exist for which we also have long-standing demographic information, as is the case with
the spotted owl. Removal experiments would take advantage of the wealth of data on spotted owls, and allow ecologists to assess
formally the impacts of an invasive species on a threatened species, as well as to suggest mitigation measures. 相似文献
196.
Joseph B. Buchanan R. J. Gutiérrez Robert G. Anthony Tim Cullinan Lowell V. Diller Eric D. Forsman Alan B. Franklin 《Biological invasions》2007,9(6):679-691
The conservation of Spotted Owl (Strix occidentalis) populations has been one of the most controversial and visible issues in United States conservation history. Coincident
with declines in Spotted Owl populations over the last three decades has been the invasion of Barred Owls (Strix varia) throughout the range of the Northern Spotted Owl (S. o. caurina) and into the range of the California Spotted Owl (S. o. occidentalis). This invasion has confused the reasons behind recent Spotted Owl declines because anecdotal and correlative information
strongly suggests that Barred Owls are a new factor influencing the declines. There is great uncertainty about all aspects
of the invasion, and this has sparked discussion about appropriate management and research responses regarding the effects
of this invasion on Spotted Owls. We present a set of possible responses to address the issue, and we discuss the relative
merits of these with regard to their efficacy given the current state of knowledge. We recommend that research specifically
aimed at learning more about the interspecific relationships of these two owls throughout the range of sympatry should begin
immediately. Approaches that seem unlikely to be useful in the short-term either because they do not facilitate knowledge
acquisition, are relatively costly, or would be technically less feasible, should not be considered viable at this time. We
believe the consequences of the invasion are potentially dire for the Spotted Owl and that research and management actions,
including the use of adaptive management, are required to inform the near- and long-term decision-making process for conservation
of Spotted Owls. 相似文献
197.
Linam Franklin Limmer Matt A. Tappero Ryan Seyfferth Angelia L. 《Plant and Soil》2022,477(1-2):135-152
Plant and Soil - Rice is a staple crop worldwide and a silicon (Si) hyperaccumulator with Si levels reaching 5–10% of its mass; this can result in desilication and Si-deficiency if plant... 相似文献
198.
199.
Reciprocal Modulation of Histone Deacetylase Inhibitors Sodium Butyrate and Trichostatin A on the Energy Metabolism of Breast Cancer Cells 下载免费PDF全文
200.
Patrick Lall Andrew J. Lindsay Sara Hanscom Tea Kecman Elizabeth S. Taglauer Una M. McVeigh Edward Franklin Mary W. McCaffrey Amir R. Khan 《The Journal of biological chemistry》2015,290(30):18817-18832
Rab GTPases recruit effector proteins, via their GTP-dependent switch regions, to distinct subcellular compartments. Rab11 and Rab25 are closely related small GTPases that bind to common effectors termed the Rab11 family of interacting proteins (FIPs). The FIPs are organized into two subclasses (class I and class II) based on sequence and domain organization, and both subclasses contain a highly conserved Rab-binding domain at their C termini. Yeast two-hybrid and biochemical studies have revealed that the more distantly related Rab14 also interacts with class I FIPs. Here, we perform detailed structural, thermodynamic, and cellular analyses of the interactions between Rab14 and one of the class I FIPs, the Rab-coupling protein (RCP), to clarify the molecular aspects of the interaction. We find that Rab14 indeed binds to RCP, albeit with reduced affinity relative to conventional Rab11-FIP and Rab25-FIP complexes. However, in vivo, Rab11 recruits RCP onto biological membranes. Furthermore, biophysical analyses reveal a noncanonical 1:2 stoichiometry between Rab14-RCP in dilute solutions, in contrast to Rab11/25 complexes. The structure of Rab14-RCP reveals that Rab14 interacts with the canonical Rab-binding domain and also provides insight into the unusual properties of the complex. Finally, we show that both the Rab coupling protein and Rab14 function in neuritogenesis. 相似文献