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41.
Social insect colonies operate without central control or any global assessment of what needs to be done by workers. Colony organization arises from the responses of individuals to local cues. Red harvester ants (Pogonomyrmex barbatus) regulate foraging using interactions between returning and outgoing foragers. The rate at which foragers return with seeds, a measure of food availability, sets the rate at which outgoing foragers leave the nest on foraging trips. We used mimics to test whether outgoing foragers inside the nest respond to the odor of food, oleic acid, the odor of the forager itself, cuticular hydrocarbons, or a combination of both with increased foraging activity. We compared foraging activity, the rate at which foragers passed a line on a trail, before and after the addition of mimics. The combination of both odors, those of food and of foragers, is required to stimulate foraging. The addition of blank mimics, mimics coated with food odor alone, or mimics coated with forager odor alone did not increase foraging activity. We compared the rates at which foragers inside the nest interacted with other ants, blank mimics, and mimics coated with a combination of food and forager odor. Foragers inside the nest interacted more with mimics coated with combined forager/seed odors than with blank mimics, and these interactions had the same effect as those with other foragers. Outgoing foragers inside the nest entrance are stimulated to leave the nest in search of food by interacting with foragers returning with seeds. By using the combined odors of forager cuticular hydrocarbons and of seeds, the colony captures precise information, on the timescale of seconds, about the current availability of food. 相似文献
42.
43.
Michal Sorek Jacob Douek Tamar Guy-Haim Noa Simon-Blecher Baruch Rinkevich 《Zoology in the Middle East.》2016,62(4):331-341
Fluorescent-amplified fragment length polymorphism (FAFLP) fingerprinting assay was used to compare the genetic diversity within and between tadpole shrimps (Notostraca) populations of Lepidurus apus (n=7) and Triops cancriformis (n=2) from rain pools in Israel. Each ephemeral water body has revealed a unique fingerprint pattern with an entailed genetic drift between nearby ponds. High similarity of genotypic diversity within each geographic area led to three clusters of water bodies, north, south and center of Israel. FAFLP assays on several newly hatched individuals of T. cancriformis revealed high identity amongst kin, as compared to L. apus where newly hatched from the same maternal source showed high diversity. Results indicate that T. cancriformis populations from Israel are probably parthenogenetic as indicated by clonal structures. The higher genetic variability in the L. apus populations and in laboratory-hatched specimens indicates the existence of sexual reproduction. 相似文献
44.
Through its various metabolites, vitamin A controls essential physiological functions. Both naturally occurring metabolites and novel retinoid analogues have shown effectiveness in many clinical settings that include skin diseases and cancer, and in animal models of human conditions affecting vision. In this review, we analyze several potential retinoid-based therapies from the point of view of drug metabolism and transport to target tissues. We focus on the endogenous factors that affect the absorption, transport, and metabolism of retinoids by taking into account data obtained from the analysis of animal models that lack the enzymes or proteins involved in the storage and absorption of retinoids. We also discuss findings of toxicity associated with retinoids in an effort to improve the outcome of retinoid-based therapies. In this context, we review evidence that esterification of retinol and retinol-based drugs within target tissues provides one of the most efficient means to improve the absorption and to reduce the toxicity associated with pharmacological doses of retinoids. Future retinoid-based therapeutic strategies could involve targeted delivery mechanisms leading to lower toxicity and improved effectiveness of retinoids. 相似文献
45.
46.
Marash L Liberman N Henis-Korenblit S Sivan G Reem E Elroy-Stein O Kimchi A 《Molecular cell》2008,30(4):447-459
DAP5 is an eIF4G protein previously implicated in mediating cap-independent translation in response to cellular stresses. Here we report that DAP5 is crucial for continuous cell survival in nonstressed cells. The knockdown of endogenous DAP5 induced M phase-specific caspase-dependent apoptosis. Bcl-2 and CDK1 were identified by two independent screens as DAP5 translation targets. Notably, the activity of the Bcl-2 IRES was reduced in DAP5 knockdown cells and a selective shift of Bcl-2 mRNA toward light polysomal fractions was detected. Furthermore, a functional IRES was identified in the 5'UTR of CDK1. At the cellular level, attenuated translation of CDK1 by DAP5 knockdown decreased the phosphorylation of its M phase substrates. Ectopic expression of Bcl-2 or CDK1 proteins partially reduced the extent of caspase activation caused by DAP5 knockdown. Thus, DAP5 is necessary for maintaining cell survival during mitosis by promoting cap-independent translation of at least two prosurvival proteins. 相似文献
47.
48.
Costas J Carrera N Domínguez E Vilella E Martorell L Valero J Gutiérrez-Zotes A Labad A Carracedo A 《Human genetics》2009,124(6):607-613
The number and frequency of susceptibility alleles at loci associated to most psychiatric disorders is largely unknown, in
spite of its relevance for the design of studies aiming to find these alleles. Both, common polymorphisms and rare mutations
may contribute to the genetic susceptibility to complex psychiatric disorders, being the relative relevance of each type of
variation currently under debate. Here, we confirmed the existence of a common protective haplotype against schizophrenia
at the dopamine D3 receptor (DRD3) gene, by replication and pooled analysis with previous data (Mantel–Haenszel χ2
P value = 0.00227; OR = 0.79, 95% CI 0.68–0.92, based on 794 cases and 1,078 controls from three independent populations of
European origin). This protective haplotype is at very low frequency in Sub-Saharan Africans (median 0.06) and at intermediate
frequencies in other populations (median 0.25). We also revealed, by examining the patterns of linkage disequilibrium around
this gene, that the protective haplotype has reached high frequency in non-African populations due to selection acting, most
probably, on a linked functional polymorphism, the non-synonymous single nucleotide polymorphism Ser9Gly (rs6280), also at
DRD3. Thus, this finding shows that the natural selection may play a role in the existence of common alleles conferring different
susceptibility to schizophrenia.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
49.
Noa Schwartz Tamar Rubinstein Linda C Burkly Christopher E Collins Irene Blanco Lihe Su Bernard Hojaili Meggan Mackay Cynthia Aranow William Stohl Brad H Rovin Jennifer S Michaelson Chaim Putterman 《Arthritis research & therapy》2009,11(5):R143
Introduction
TNF-like weak inducer of apoptosis (TWEAK) has been implicated as a mediator of chronic inflammatory processes via prolonged activation of the NF-κB pathway in several tissues, including the kidney. Evidence for the importance of TWEAK in the pathogenesis of lupus nephritis (LN) has been recently introduced. Thus, TWEAK levels may serve as an indication of LN presence and activity.Methods
Multicenter cohorts of systemic lupus erythematosus (SLE) patients and controls were recruited for cross-sectional and longitudinal analysis of urinary TWEAK (uTWEAK) and/or serum TWEAK (sTWEAK) levels as potential biomarkers of LN. The performance of TWEAK as a biomarker for nephritis was compared with routinely used laboratory tests in lupus patients, including anti-double stranded DNA antibodies and levels of C3 and C4.Results
uTWEAK levels were significantly higher in LN patients than in non-LN SLE patients and other disease control groups (P = 0.039). Furthermore, uTWEAK was better at distinguishing between LN and non-LN SLE patients than anti-DNA antibodies and complement levels, while high uTWEAK levels predicted LN in SLE patients with an odds ratio of 7.36 (95% confidence interval = 2.25 to 24.07; P = 0.001). uTWEAK levels peaked during LN flares, and were significantly higher during the flare than at 4 and 6 months prior to or following the flare event. A linear mixed-effects model showed a significant association between uTWEAK levels in SLE patients and their disease activity over time (P = 0.008). sTWEAK levels, however, were not found to correlate with the presence of LN or the degree of nephritis activity.Conclusions
High uTWEAK levels are indicative of LN, as opposed to non-LN SLE and other healthy and disease control populations, and reflect renal disease activity in longitudinal follow-up. Thus, our study further supports a role for TWEAK in the pathogenesis of LN, and provides strong evidence for uTWEAK as a candidate clinical biomarker for LN. 相似文献50.