全文获取类型
收费全文 | 342篇 |
免费 | 29篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 26篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 16篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 10篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1968年 | 3篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1964年 | 4篇 |
1963年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有371条查询结果,搜索用时 15 毫秒
61.
The opening of the Suez Canal in 1869 enabled the invasion of more than 100 alien fish species into the Mediterranean. The aim of the present study was to compare the diet of native and alien fish species and to identify possibly shared food resources. We examined the diet composition of 13 of the most abundant fish species (6 alien, 7 native) on shallow soft bottom off southern Israel. All 13 species are omnivorous/carnivorous. The native fish exhibited a wider diversity of food types than the aliens. Alien fish prey upon and are preyed by native species as well as by other alien fish. A high level of diet overlap was found among some species, the aliens Saurida lessepsianus and Scomberomorus commerson overlapped with the native Synodus saurus; and the alien Nemipterus randalli with the native species Pagrus caeruleostictus, Lithognathus mormyrus and Pagellus erythrinus. The identified diet overlap is discussed, and the possibility of competitive interactions between these species is considered. 相似文献
62.
L. Lo Cicero V. Catara C. P. Strano P. Bella P. Madesis A. R. Lo Piero 《Biologia Plantarum》2017,61(1):169-177
Glutathione transferases (GSTs) mainly catalyze the nucleophilic addition of glutathione to a large variety of hydrophobic molecules participating to the vacuole compartmentalization of many toxic compounds. In this work, the putative tolerance of transgenic tobacco plants over-expressing CsGSTU genes towards the chloroacetanilide herbicide alachlor was investigated. Our results show that the treatment with 0.0075 mg cm-3 of alachlor strongly affects the growth of both wild type and transformed tobacco seedlings with the sole exception of the transgenic lines overexpressing CsGSTU2 isoform that are barely influenced by herbicide treatment. In order to correlate the in planta studies with enzyme properties, recombinant CsGSTs were in vitro expressed and tested for GST activity using alachlor as substrate. The recombinant GSTU2 enzyme was twice more active than GSTU1 in conjugating alachlor to GSH thus indicating that CsGSTU2 might play a crucial role in the plant defense against the herbicide. Moreover, as a consequence of the infiltration with a bacterial suspension of the P. syringae pv. tabaci, transgenic tobacco plants but not wild type plants bestowed the capability to limit toxic metabolite diffusion through plant tissues as indicated by the absence of chlorotic halos formation. Consequently, the transgenic tobacco plants described in the present study might be utilized for phytoremediation of residual xenobiotics in the environment and might represent a model for engineering plants that resist to pathogen attack. 相似文献
63.
Erzsbet Mernyk Sndor Bartha Lili Kczn Rebeka Jjrt Vivien Resch Gbor Paragi Mt Vgvlgyi Attila Hunyadi Bella Bruszel Istvn Zupk Renta Minorics 《Journal of enzyme inhibition and medicinal chemistry》2021,36(1):1931
Microwave-assisted phospha-Michael addition reactions were carried out in the 13α-oestrone series. The exocyclic 16-methylene-17-ketones as α,β-unsaturated ketones were reacted with secondary phosphine oxides as nucleophilic partners. The addition reactions furnished the two tertiary phosphine oxide diastereomers in high yields. The main product was the 16α-isomer. The antiproliferative activities of the newly synthesised organophosphorus compounds against a panel of nine human cancer cell lines were investigated by means of MTT assays. The most potent compound, the diphenylphosphine oxide derivative in the 3-O-methyl-13α-oestrone series (9), exerted selective cell growth-inhibitory activity against UPCI-SCC-131 and T47D cell lines with low micromolar IC50 values. Moreover, it displayed good tumour selectivity property determined against non-cancerous mouse fibroblast cells. 相似文献
64.
Schluter C Lam KK Brumm J Wu BW Saunders M Stevens TH Bryan J Conibear E 《Molecular biology of the cell》2008,19(4):1282-1294
Endosomal transport is critical for cellular processes ranging from receptor down-regulation and retroviral budding to the immune response. A full understanding of endosome sorting requires a comprehensive picture of the multiprotein complexes that orchestrate vesicle formation and fusion. Here, we use unsupervised, large-scale phenotypic analysis and a novel computational approach for the global identification of endosomal transport factors. This technique effectively identifies components of known and novel protein assemblies. We report the characterization of a previously undescribed endosome sorting complex that contains two well-conserved proteins with four predicted membrane-spanning domains. Vps55p and Vps68p form a complex that acts with or downstream of ESCRT function to regulate endosomal trafficking. Loss of Vps68p disrupts recycling to the TGN as well as onward trafficking to the vacuole without preventing the formation of lumenal vesicles within the MVB. Our results suggest the Vps55/68 complex mediates a novel, conserved step in the endosomal maturation process. 相似文献
65.
Foraminiferal analyses carried out on the VTR01/8 core (Tremiti Islands, Adriatic Sea) lead to the reconstruction of the paleoenvironmental evolution of the area. Although the core site is located at about 1000 km from the Po delta, this study shows that the installation of the recent sedimentological and run-off system (with a shore parallel clay-belt) is similar to that described at sites much closer to the Po delta. The statistical analysis singled out four associations that correspond to four distinct environments. The ecological preferences of the most abundant taxa that characterize each environment reveal that from the bottom of the core to − 50 cm, there is a slight increase of the water depth after which the water depth increases until the present level. Association A (that comprises subclusters A1, A2 and A3) is characterized by shallow-water taxa (e.g., Ammonia beccarii, Quinqueloculina spp. and Elphidium granosum) showing that in the past an infralittoral environment typified the Tremiti High. The subclusters of Association A show that during the deposition of the lower part of the core there had been an alternation of phases characterized by different degrees of riverine influence: the site was at first under the influence of river outflow (A2) that later bypassed the core site (A3) and then came back, although located further away than before (A1). With the rising of the sea level, the Tremiti High became only marginally affected by river influence because the core site is located at a considerable distance from the Po outlets and seaward with respect to the center of the modern mud-belt. As a matter of fact, association B (Bulimina marginata, Cassidulina carinata and Textularia spp.), which starts at − 46 cm, shows the typical characteristics of the modern mud-belt outer-shelf assemblage, although the presence of opportunistic species is limited by the distant position with respect to the Po delta. 相似文献
66.
Bella Devassy Tony Dinesh Goyal Sunil Khanna 《International biodeterioration & biodegradation》2009,63(4):462-469
The decolorization potential of two bacterial consortia developed from a textile wastewater treatment plant showed that among the two mixed bacterial culture SKB-II was the most efficient in decolorizing individual as well as mixture of dyes. At 1.3 g L?1 starch supplementation in the basal medium by the end of 120 h decolorization of 80–96% of four out of the six individual azo dyes Congo red, Bordeaux, Ranocid Fast Blue and Blue BCC (10 mg L?1) was noted. The culture exhibited good potential ability in decolorizing 50–60% of all the dyes (Congo red, Bordeaux, Ranocid Fast Blue and Blue BCC) when present as a mixture at 10 mg L?1. The consortium SKB-II consisted of five different bacterial types identified by 16S rDNA sequence alignment as Bacillus vallismortis, Bacillus pumilus, Bacillus cereus, Bacillus subtilis and Bacillus megaterium which were further tested to decolorize dyes. The efficient ability of this developed consortium SKB-II to decolorize individual dyes and textile effluent using packed bed reactors is being carried out. 相似文献
67.
Priolo A Vasta V Fasone V Lanza CM Scerra M Biondi L Bella M Whittington FM 《Animal : an international journal of animal bioscience》2009,3(3):454-460
A 2 × 2 factorial experiment was carried out to evaluate the effect of herbage or concentrate feeding system and tannin addition to diet on skatole and indole in ruminal fluid and adipose tissue and meat sensory properties. Twenty-eight male lambs aged 45 days were randomly assigned to one of two feeding systems (vetch green herbage or concentrates, n = 14) and within feeding system to one supplement (quebracho tannins added to the diet or none). Animals were kept in singular pens and slaughtered at the age of 105 days. Indole (P < 0.05) and skatole (P < 0.01) concentrations in ruminal fluid were higher in lambs fed herbage compared to those given concentrates. Skatole in ruminal fluid tended to be present at lower concentrations in animals that received the tannin supplementation (P = 0.07). Indole was also higher in the caudal fat of animals fed green vetch compared to those fed concentrate (P = 0.04). Skatole concentration was lower in the fat of lambs fed concentrates compared to those given herbage (P = 0.05) and was lower in the fat of animals supplemented with tannins compared to the animals not supplemented (P = 0.01). Sheep meat odour was lower in meat from animals supplemented with tannins compared to those not supplemented (P < 0.01). It is concluded that tannins are more effective in reducing skatole formation in ruminants when they are associated with concentrate diets than green herbages. 相似文献
68.
69.
Irit Cohen Myriam Maoz Hagit Turm Sorina Grisaru-Granovsky Bella Maly Beatrice Uziely Einat Weiss Rinat Abramovitch Eithan Gross Oded Barzilay Yun Qiu Rachel Bar-Shavit 《PloS one》2010,5(6)
Background
While protease-activated-receptor 1 (PAR1) plays a central role in tumor progression, little is known about the cell signaling involved.Methodology/Principal Findings
We show here the impact of PAR1 cellular activities using both an orthotopic mouse mammary xenograft and a colorectal-liver metastasis model in vivo, with biochemical analyses in vitro. Large and highly vascularized tumors were generated by cells over-expressing wt hPar1, Y397Z hPar1, with persistent signaling, or Y381A hPar1 mutant constructs. In contrast, cells over-expressing the truncated form of hPar1, which lacks the cytoplasmic tail, developed small or no tumors, similar to cells expressing empty vector or control untreated cells. Antibody array membranes revealed essential hPar1 partners including Etk/Bmx and Shc. PAR1 activation induces Etk/Bmx and Shc binding to the receptor C-tail to form a complex. Y/A mutations in the PAR1 C-tail did not prevent Shc-PAR1 association, but enhanced the number of liver metastases compared with the already increased metastases obtained with wt hPar1. We found that Etk/Bmx first binds via the PH domain to a region of seven residues, located between C378-S384 in PAR1 C-tail, enabling subsequent Shc association. Importantly, expression of the hPar1-7A mutant form (substituted A, residues 378-384), which is incapable of binding Etk/Bmx, resulted in inhibition of invasion through Matrigel-coated membranes. Similarly, knocking down Etk/Bmx inhibited PAR1-induced MDA-MB-435 cell migration. In addition, intact spheroid morphogenesis of MCF10A cells is markedly disrupted by the ectopic expression of wt hPar1. In contrast, the forced expression of the hPar1-7A mutant results in normal ball-shaped spheroids. Thus, by preventing binding of Etk/Bmx to PAR1 -C-tail, hPar1 oncogenic properties are abrogated.Conclusions/Significance
This is the first demonstration that a cytoplasmic portion of the PAR1 C-tail functions as a scaffold site. We identify here essential signaling partners, determine the hierarchy of binding and provide a platform for therapeutic vehicles via definition of the critical PAR1 -associating region in the breast cancer signaling niche. 相似文献70.
Ferrous iron‐ and ammonium‐rich diffuse vents support habitat‐specific communities in a shallow hydrothermal field off the Basiluzzo Islet (Aeolian Volcanic Archipelago).
下载免费PDF全文
![点击此处可从《Geobiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)