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101.
Anu Liikanen Eeva Ratilainen Sanna Saarnio Jukka Alm Pertti J. Martikainen Jouko Silvola 《Freshwater Biology》2003,48(3):500-511
SUMMARY 1. The effects of increasing CO2 and nitrogen loading and of a change in water table and temperature on littoral CH4, N2O and CO2 fluxes were studied in a glasshouse experiment with intact sediment cores including vegetation (mainly sedges), taken from a boreal eutrophic lake in Finland. Sediments with the water table held at a level of 0 or at ?15 cm were incubated in an atmosphere of 360 or 720 p.p.m. CO2 for 18 weeks. The experiment included fertilisation with NO3– and NH4+ (to a total 3 g N m?2). 2. Changes in the water table and temperature strongly regulated sediment CH4 and cCO2 fluxes (community CO2 release), but did not affect N2O emissions. Increase in the water table increased CH4 emissions but reduced cCO2 release, while increase in temperature increased emissions of both CO2 and CH4. 3. The raised CO2 increased carbon turnover in the sediments, such that cCO2 release was increased by 16–26%. However, CH4 fluxes were not significantly affected by raised CO2, although CH4 production potential (at 22 °C) of the sediments incubated at high CO2 was increased. In the boreal region, littoral CH4 production is more likely to be limited by temperature than by the availability of carbon. Raised CO2 did not affect N2O production by denitrification, indicating that this process was not carbon limited. 4. A low availability of NO3– did severely limit N2O production. The NO3– addition caused up to a 100‐fold increase in the fluxes of N2O. The NH4+ addition did not increase N2O fluxes, indicating low nitrification capacity in the sediments. 相似文献
102.
Eeva Therman Gloria E. Sarto Catherine G. Palmer Hanna Kallio Carter Denniston 《Human genetics》1979,50(1):59-64
Summary In three women with a 46,XXq- chromosome constitution, the length of the deletion was expressed as the ratio of the remaining part of Xq to Xp
. In one of them (KH) this ratio was 0.33, in another (GE) 0.59, and in the third (AP) the ratio fell between these values. The break in KH is more or less on the border of the Q-dark proximal region. A comparison with relevant X-autosomal translocations indicates that the X inactivation center lies near, but not at the border of, the Q-dark and the adjoining bright region (c and d). 相似文献
103.
We have isolated the infiltrating inflammatory cells from rejecting rat kidney allografts via collagenase-DNase dispersion and 1g velocity sedimentation. A representative cell sample, devoid of blood contamination and subclass-specific cell losses, is thus obtained in a functionally viable state. The infiltrating inflammatory cells display an immunologically specific in vitro cytotoxicity to donor-strain lymphoblasts. The peak cytotoxicity takes place in the graft before it takes place in the lymphatic system of the recipient rat. The allograft-infiltrating cytotoxic cells display a far wider distribution profile in 1g velocity than do the recipient spleen killer cells. The donor-strain lymphoblasts are highly sensitive to the lytic effect of both allograft-infiltrating and spleen killer cells, but the transplant parenchymal cells, consisting mainly of tubular and glomerular cells, are relatively insensitive. The findings suggest heterogeneity of the effector cells in the allograft infiltrate vs that in the spleen, and indicate that different structures of the target organ are differently sensitive to cellular cytotoxicity. 相似文献
104.
The occurrence of chromosome breaks and reunion of sister chromatids in lymphocytes of two patients with Bloom's syndrome has been compared with those found in X-rayed and control cells. The distribution of breaks in BS is non-random both between and within chromosomes, the centric regions of certain chromosomes being preferentially involved. The following working hypotheses are put forward: When chromosome breaks in human lymphocytes occur in G0— G1, practically no sister chromatid reunion (SCR) takes place, whereas ends created by an S—G2 break show a considerable tendency to SCR. We propose further that chromosome aberrations in BS mainly result from breaks in S—G2, including possible U-type rejoining of sister chromatid exchanges. Fragments extra to an intact chromosome complement result from a chromatid break or an asymmetrical chromatid translocation in a previous mitosis. 相似文献
105.
Koskinen H Pehkonen P Vehniäinen E Krasnov A Rexroad C Afanasyev S Mölsa H Oikari A 《Biochemical and biophysical research communications》2004,320(3):745-753
We used high-density cDNA microarray in studies of responses of rainbow trout fry at sublethal ranges of beta-naphthoflavone, cadmium, carbon tetrachloride, and pyrene. The differentially expressed genes were grouped by the functional categories of Gene Ontology. Significantly different response to the studied compounds was shown by a number of classes, such as cell cycle, apoptosis, signal transduction, oxidative stress, subcellular and extracellular structures, protein biosynthesis, and modification. Cluster analysis separated responses to the contaminants at low and medium doses, whereas at high levels the adaptive reactions were masked with general unspecific response to toxicity. We found enhanced expression of many mitochondrial proteins as well as genes involved in metabolism of metal ions and protein biosynthesis. In parallel, genes related to stress and immune response, signal transduction, and nucleotide metabolism were down-regulated. We performed computer-assisted analyses of Medline abstracts retrieved for each compound, which helped us to indicate the expected and novel findings. 相似文献
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109.
Eeva Heinaru Eve Vedler Jekaterina Jutkina Merit Aava & Ain Heinaru 《FEMS microbiology ecology》2009,70(3):231-242
The complete 83 042-bp nucleotide sequence of the IncP-9 naphthalene degradation plasmid pNAH20 from Pseudomonas fluorescens PC20 exhibits striking similarity in size and sequence to another naphthalene (NAH) plasmid pDTG1. However, the positions of insertion sequence (IS) elements significantly alter both catabolic and backbone functions provided by the two plasmids. In pDTG1, insertion of a pCAR1 IS Pre1 -like element disrupts expression of the lower naphthalene operon and this strain utilizes the chromosomal pathway for complete naphthalene degradation. In pNAH20, this operon is intact and functional. The transfer frequency of pNAH20 is 100 times higher than that of pDTG1 probably due to insertion of the pCAR1 IS Pre2 -like element into the mpfR gene coding for a putative repressor of the mpf operon responsible for mating pilus formation. We also demonstrate in situ plasmid transfer – we isolated a rhizosphere transconjugant strain of pNAH20, P. fluorescens NS8. The plasmid pNS8, a derivative of pNAH20, lacks the ability to self-transfer as a result of an additional insertion event of IS Pre2 -like element that disrupts the gene coding for VirB2-like major pilus protein MpfA. The characteristics of the strain PC20 and the conjugal transfer/mobilization capacity of pNAH20 (or its backbone) make this strain/plasmid a potentially successful tool for bioremediation applications. 相似文献
110.
David G Parr Asger Dirksen Eeva Piitulainen Chunqin Deng Marion Wencker Robert A Stockley 《Respiratory research》2009,10(1):75