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11.
Toni Gabaldón Christophe Dessimoz Julie Huxley-Jones Albert J Vilella Erik LL Sonnhammer Suzanna Lewis 《Genome biology》2009,10(9):1-3
A report of the 24th International Conference on Yeast Genetics and Molecular Biology, Manchester, UK, 19-24 July 2009. 相似文献
12.
LL. Lloyd 《The Annals of applied biology》1943,30(4):358-364
The incidence of the sewage fly, Psychoda alternata Say, breeding almost free from other insect competitors in a bacteria bed at Huddersfield is examined. Its general seasonal trend is marked by periods of peak output explained on the theory that there are two successions of generations running persistently and alternating with one another. Such behaviour has previously been demonstrated for another sewage fly, Spaniotoma minima , and has been shown to be instituted by irregular temperatures in autumn and spring. In Psychoda alternata a special type of intraspecific competition is set-up in the warmer months when the cycles are rapid, for the larvae of one succession must start life in a bed just depleted of food by the other. Therefore large and small outbursts of the fly tend to alternate. The discharges of solids from the bed have a detailed periodicity corresponding to the alternations in the successions of the fly. 相似文献
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Although gammalinolenic acid (GLA) and eicosapentaenoic acid (EPA) have independently been reported to suppress growth of cancer cells, their relative potencies are unknown. To determine the possible attenuating efficacies of dietary GLA or EPA on prostate carcinogenesis, we hereby report the in vitro effects of GLA, EPA and their 15-lipoxygenase (15-LOX) metabolites: 15(S)-HETrE and 15(S)-HEPE, respectively, on growth and arachidonic acid (AA) metabolism in human androgen-dependent (LNCaP) and androgen-independent (PC-3) prostatic cancer cells in culture. Specifically, both cells were preincubated respectively with the above PUFAs. Growth was determined by [3H]thymidine uptake and AA metabolism by HPLC analysis of the extracted metabolites. Our data revealed increased biosynthesis of prostaglandin E2 (PGE2) and 5-hydroxyeicosatetraenoic acid (5(S)-HETE) by both cells. Preincubation of the cells with 15(S)-HETrE or 15(S)-HEPE more markedly inhibited cellular growth and AA metabolism when compared to precursor PUFAs. Notably, 15(S)-HETrE exerted the greatest inhibitory effects. These findings therefore imply that dietary GLA rather than EPA should better attenuate prostate carcinogenesis via its in vivo generation of 15(S)-HETrE, thus warranting exploration. 相似文献
15.
In the rainfed lowlands, temporary loss of soil-water saturation during crop growth is a common factor limiting rice (Oryza
sativa L.) yield but its effects on phosphorus (P) availability are poorly understood. Rice plants were transplanted into
pots containing soils that were either continuously flooded, maintained at field capacity or flooded and then dried to field
capacity for 3 weeks during the vegetative stage. A black clay soil (Kandic Plinthaquult) and a sandy soil (Plinthustalf)
from south-east Cambodia were compared with or without amendments by rice straw and P fertilizer.
Under continuously flooded conditions, the growth of rice was vigorous without straw addition and there was a strong response
of rice growth to the addition of P fertilizer. The soil underwent reduction, which increased pH from 4.2 to 5.5 or 6.0, in
the black clay or sandy soil, respectively. By contrast, a loss of soil-water saturation 3 weeks before panicle initiation
(PI) markedly impaired the growth of rice. This was not through any effect of water stress, and the growth reductions were
not as strong as with continued loss of soil-water saturation from transplanting to PI. Fluctuations in soil pH and Eh corresponded
closely to changes in soil-water regimes. Growth reductions were attributed to reduced shoot P levels resulting from the decline
in P availability during the loss of soil-water saturation. The addition of rice straw stimulated soil reduction and lessened
changes in soil pH and Eh during the loss of soil-water saturation in both soils. Straw addition enhanced P uptake by the
rice plants during loss of soil-water saturation, but its beneficial effects could not be attributed to the direct addition
of P, N or K to the soils. Thus the application of rice straw may be effective in lessening the effects of temporary loss
of soil-water saturation on rice growth in lowland rice soils by minimising the decline in P availability.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Background
Distance-based methods are popular for reconstructing evolutionary trees thanks to their speed and generality. A number of methods exist for estimating distances from sequence alignments, which often involves some sort of correction for multiple substitutions. The problem is to accurately estimate the number of true substitutions given an observed alignment. So far, the most accurate protein distance estimators have looked for the optimal matrix in a series of transition probability matrices, e.g. the Dayhoff series. The evolutionary distance between two aligned sequences is here estimated as the evolutionary distance of the optimal matrix. The optimal matrix can be found either by an iterative search for the Maximum Likelihood matrix, or by integration to find the Expected Distance. As a consequence, these methods are more complex to implement and computationally heavier than correction-based methods. Another problem is that the result may vary substantially depending on the evolutionary model used for the matrices. An ideal distance estimator should produce consistent and accurate distances independent of the evolutionary model used. 相似文献19.
Induction of cytochrome P-450IA1, IA2, IIB1, IIB2 and IIE1 by broccoli in rat liver and colon 总被引:2,自引:0,他引:2
Ingestion of broccoli or other cruciferous vegetables inhibits the induction of cancer by chemicals and modifies some cytochrome P-450 enzyme activities. The effect of dietary broccoli on the levels of P450IA and IIB mRNA and proteins in rat liver and colon has been studied. Rats were fed a ten percent broccoli diet for 7 days. The expression of the cytochrome P-450 forms was altered to a different extent in the liver and colon. The level of total P450IA mRNA in the liver was increased by the broccoli together with the P450IA1 and IA2 proteins. Colonic P450IA1 mRNA and protein were induced by the broccoli diet, whereas only P450IA2 protein and not mRNA was detectable in colon, but the protein level was unaffected by the broccoli diet. Liver P450IIB and IIE1 proteins were increased by the broccoli diet, whereas the level of P450IIB mRNAs was not affected. In contrast, the P450IIB mRNA levels were reduced but the protein levels were increased in colon and we suggest that a feedback mechanism caused the decrease of the P450IIB mRNAs levels. Because the ratio between activation and deactivation may be an important risk determinant, we conclude that the protective effect of the broccoli diet on chemically induced tumors in rodents may be caused by the broccoli-induced changes in P450IA and IIB associated enzyme activities. 相似文献
20.
Palmfeldt J Vang S Stenbroen V Pavlou E Baycheva M Buchal G Monavari AA Augoustides-Savvopoulou P Mandel H Gregersen N 《Journal of proteome research》2011,10(5):2389-2396
Deficiency of the sulfide metabolizing protein ETHE1 is the cause of ethylmalonic encephalopathy (EE), an inherited and severe metabolic disorder. To study the molecular effects of EE, we performed a proteomics study on mitochondria from cultured patient fibroblast cells. Samples from six patients were analyzed and revealed seven differentially regulated proteins compared with healthy controls. Two proteins involved in pathways of detoxification and oxidative/reductive stress were underrepresented in EE patient samples: mitochondrial superoxide dismutase (SOD2) and aldehyde dehydrogenase X (ALDH1B). Sulfide:quinone oxidoreductase (SQRDL), which takes part in the same sulfide pathway as ETHE1, was also underrepresented in EE patients. The other differentially regulated proteins were apoptosis inducing factor (AIFM1), lactate dehydrogenase (LDHB), chloride intracellular channel (CLIC4) and dimethylarginine dimethylaminohydrolase 1 (DDAH1). These proteins have been reported to be involved in encephalopathy, energy metabolism, ion transport, and nitric oxide regulation, respectively. Interestingly, oxidoreductase activity was overrepresented among the regulated proteins indicating that redox perturbation plays an important role in the molecular mechanism of EE. This observation may explain the wide range of symptoms associated with the disease, and highlights the potency of the novel gaseous mediator sulfide. 相似文献