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31.
Josephine Geertsen Keller Kirstine Mejlstrup Hymller Maria Eriksen Thorsager Noriko
Y Hansen Jens
Uldum Erlandsen Cinzia Tesauro Anne
Katrine
W Simonsen Anne
Bech Andersen Kamilla Vands
Petersen Lise
Lolle Holm Magnus Stougaard Brage
Storstein Andresen Peter Kristensen Rikke Frhlich Birgitta
R Knudsen 《Nucleic acids research》2022,50(11):6332
32.
Tryptophan hydroxylase oxidizes L-tryptophan to 5-hydroxy-L-tryptophan in the rate-determining step of serotonin biosynthesis. We have determined the X-ray crystal structure (1.7 A) of a truncated functional form of human tryptophan hydroxylase with the bound cofactor analogue 7,8-dihydro-L-biopterin, providing the first atomic-resolution information for the catalytic domain of this important enzyme. Comparison of the three-dimensional structures of all three members of the aromatic amino acid hydroxylase family--tyrosine hydroxylase, phenylalanine hydroxylase, and tryptophan hydroxylase--reveals important differences at the active sites. 相似文献
33.
Abstract
Seasonal variation in bacterioplankton abundance, biomass, and bacterioplankton production was studied over eight years in
hypertrophic Lake S?byg?rd. Biologically, the lake is highly variable; this is due mainly to large interannual variation in
fish recruitment. Bacterioplankton production was low during winter, typically 1–3 × 107 cells l−1 h−1, and high during summer, albeit greatly fluctuating with maximum rates typically ranging from 60 to 90 × 107 cells l−1 h−1 (or 0.4 to 0.6 mg C l−1 day−1). Less pronounced variations were found in bacterioplankton abundance, which typically ranged from 3–8 × 109 cells l−1 in winter to 15–30 × 109 cells l−1 during summer. The specific growth rate of bacterioplankton varied from 0.02–0.2 d−1 in winter to 0.5–2.3 day−1 during summer. Interpolated mean bacterioplankton production, in terms of carbon, ranged from 0.08 to 0.16 mg C l−1 day−1, corresponding to 1.6–5.5% of the phytoplankton production, while biomass ranged from 0.28 to 0.36 mg C l−1, corresponding to 1.9–4.6% of the phytoplankton biomass. We conducted regression analysis, relating the bacterioplankton
variables to a number of environmental variables, and evaluated the interannual parameter variability. Chlorophyll a and phytoplankton production contributed less to the variation in the bacterioplankton variables than in most previous analyses
using data from less eutrophic systems. We suggest that the proportion of phytoplankton production that is channelized through
bacterioplankton in lakes decreases with increasing trophic state and decreasing mean depth. This probably reflects a concurrent
increase in fish predation on macrozooplankton and loss by sedimentation. An important part of the residual variation in the
equations hitherto proposed in the literature could be explained by variation in macrozooplankton biomass and pH > 10.2. A
negative effect of high pH on bacterioplankton production was confirmed by laboratory experiments. The impact of different
zooplankton varies considerably, with Daphnia seeming to have a negative impact on bacterioplankton abundance and, thereby, indirectly on bacterioplankton production,
while Bosmina, rotifers, and cyclopoid copepods seem to stimulate both abundance and production. Bosmina apparently also stimulate the bacterioplankton specific growth rate.
Received: 8 February 1996; Accepted: 16 July 1996 相似文献
34.
Niels Thyssen Mogens Erlandsen Erik Jeppesen Christian Ursin 《International Review of Hydrobiology》1987,72(4):405-429
The rate coefficient K2 for the exchange of oxygen between flowing water and the atmosphere (reaeration) has been studied in six Danish streams covering a relatively wide range of hydraulic conditions, pollutional loading, and macrophyte abundance. 103 K2-measurements were performed in 1978–85. 82 measurements were obtained applying 5 different indirect methods all balancing the sources and sinks of stream dissolved oxygen under conditions of normal operation of the system (3 methods) and under artificial depletion of the oxygen concentration of the stream water by addition of sodium sulphite (2 methods). 21 K2-values were determined directly applying a gaseous tracer (krypton-85) for reaeration. Guidelines for selecting a proper method to determine K2 knowing macrophyte biomass and loading characteristics of the particular stream are provided. 相似文献
35.
36.
OD Røe A Szulkin E Anderssen A Flatberg H Sandeck T Amundsen SE Erlandsen K Dobra SH Sundstrøm 《PloS one》2012,7(8):e40521
Background
Pemetrexed, a multi-folate inhibitor combined with a platinum compound is the first-line treatment of malignant mesothelioma, but median survival is still one year. Intrinsic and acquired resistance to pemetrexed is common, but its biological basis is obscure. Here we report for the first time a genome-wide profile of acquired resistance in the tumour from an exceptional case with advanced pleural mesothelioma and almost six years survival after 39 cycles of second-line pemetrexed/carboplatin treatment.Methodology and Principal Findings
Genome-wide analysis with Illumina BeadChip Kit of 25,000 genes was performed on mRNA from pre-treatment and post-resistance biopsies from this individual as well on case and control samples from our previously published study (in total 17 samples). Cell specific expression of proteins encoded by selected genes were analysed by immunohistochemistry. Serial serum levels of CA125, CYFRA21-1 and SMRP levels were examined. TS protein, the main target of pemetrexed was overexpressed. Proteins and genes related to DNA damage response, elongation and telomere extension and repair related directly and indirectly to platinum resistance were overexpressed, as the CHK1 protein and the genes CHEK2, LIG3, POLD1, POLA2, FANCD2, PRPF19, RECQ5 respectively, the last two not previously described in mesothelioma. We observed a down-regulation of leukocyte transendothelial migration and cell adhesion molecules pathways. Silencing of NT5C in two mesothelioma cell lines did not sensitize the cells to Pemetrexed. Proposed resistance markers are TS, KRT7/ CK7, TYMP/ thymidine phosphorylase and down-regulated SPARCL1 and CDKN1B. Moreover, comparison of the primary expression of the sensitive versus a primary resistant case showed multi-fold overexpressed DNA repair, cell cycle, cytokinesis, and spindle formation in the latter. Serum CA125 and SMRP reflected the clinical and radiological course and tumour burden.Conclusions
Genome-wide microarray of mesothelioma pre- and post-resistance biopsies indicated a novel resistance signature to pemetrexed/carboplatin that deserve validation in a larger cohort. 相似文献37.
NM Kouyoumdzian NL Rukavina Mikusic G Cao MR Choi SL Della Penna BE Fernández 《Biotechnic & histochemistry》2016,91(8):510-521
We studied the effects of tempol, an oxygen radical scavenger, on hydrosaline balance in rats with acute sodium overload. Male rats with free access to water were injected with isotonic (control group) or hypertonic saline solution (0.80 mol/l NaCl) either alone (Na group) or with tempol (Na-T group). Hydrosaline balance was determined during a 90 min experimental period. Protein expressions of aquaporin 1 (AQP1), aquaporin 2 (AQP2), angiotensin II (Ang II) and endothelial nitric oxide synthase (eNOS) were measured in renal tissue. Water intake, creatinine clearance, diuresis and natriuresis increased in the Na group. Under conditions of sodium overload, tempol increased plasma sodium and protein levels and increased diuresis, natriuresis and sodium excretion. Tempol also decreased water intake without affecting creatinine clearance. AQP1 and eNOS were increased and Ang II decreased in the renal cortex of the Na group, whereas AQP2 was increased in the renal medulla. Nonglycosylated AQP1 and eNOS were increased further in the renal cortex of the Na-T group, whereas AQP2 was decreased in the renal medulla and was localized mainly in the cell membrane. Moreover, p47-phox immunostaining was increased in the hypothalamus of Na group, and this increase was prevented by tempol. Our findings suggest that tempol causes hypernatremia after acute sodium overload by inhibiting the thirst mechanism and facilitating diuresis, despite increasing renal eNOS expression and natriuresis. 相似文献
38.
39.
40.
Dr. N. S. Halmi J. A. Parsons S. L. Erlandsen Theresa Duello 《Cell and tissue research》1975,158(4):497-507
Growth hormone and prolactin cells were immunostained in human hypophyses with antibody against rat growth hormone or prolactin and the peroxidase-antiperoxidase complex. Growth hormone cells were round and, in normal pituitaries, arranged in sizable groups. Prolactin cells occurred singly and were less numerous; they were often extensively branched. Only a few prolactin cells stained with carmoisine. Incubation of the antibody with an excess of the appropriate antigen greatly diminished or abolished immunostaining; absorption of anti-prolactin with growth hormone often enhanced it. Prolactin cells were somewhat hypertrophied and hyperplastic in a neonate. Many of them stained with carmoisine. An even greater hypertrophy and hyperplasia of these cells (which pushed apart the growth hormone cells) was found in a lactating woman. Immunostained giant prolactin cells were also observed. Staining of the prolactin cells with carmoisine was extensive. Upon prolonged exposure to anti-growth hormone antibody, ACTH/MSH cells also showed immunostaining which was abolished by absorption of the antiserum with growth hormone but not with synthetic 1-24ACTH. Growth hormone cells evidently correspond to the alpha acidophils of Romeis, prolactin cells in lactation to his eta cells; the relation of his epsilon cells to the pleomorphic "resting" prolactin cells is not clear. 相似文献