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81.
The long-term benthic disturbance experiment (BENDEX) was started on the eastern Weddell Sea shelf off Austasen (Antarctica)
during ‘Polarstern’ cruise ANT XXI/2 in December 2003 to simulate the impact of grounding icebergs on the seabed and follow
the steps and timescales of recovery of disturbed benthos and demersal fish communities. Here, we report the basic approach
and first results for this experimental field study. By means of 11 densely-placed hauls with a modified bottom trawl, a seabed
area of approximately 100 × 1000 m was artificially scoured to inflict a similar damage to the benthic habitats as a grounding
iceberg. Before the disturbance event and 11 days after it, the seafloor communities were sampled (invertebrate assemblages
by multibox corers, the fish fauna by trawl hauls) and comparatively analyzed. Sediment texture and chemistry was not significantly
altered by the heavy disturbance inflicted by repeated trawling, whereas the fauna was negatively affected. Invertebrate benthic
biomass was drastically reduced by a factor of 10, while mean abundances were only slightly reduced. Demersal fish biomass
and abundance were slightly but not significantly smaller after the disturbance. Effects of disturbance became more evident
in the composition of the fish fauna, with Trematomus pennelli and T. hansoni being dominant at disturbed sites, whereas Chionodraco myersi was the dominant species in trawl catches from undisturbed stations. 相似文献
82.
83.
Kenn Gerdes 《The EMBO journal》2009,28(3):171-172
84.
Hanne N. Rasmussen Bjarke Veierskov Jens Hansen-Møller Rikke Nørbæk Ulrik Bräuner Nielsen 《Journal of Plant Growth Regulation》2009,28(2):154-166
Conifer trees are routinely manipulated hormonally to increase flowering, branching, or adjust crown shape for production
purposes. This survey of internal cytokinin levels provides a background for such treatments in Abies nordmanniana, a tree of great economic interest. Reference points in the crown and root system were sampled destructively in 4- and 6-year-old
trees and analyzed for a range of cytokinins by LC-MS/MS. No seasonal patterns were detected in the root samples, and a major
portion of cytokinin was in conjugated forms. Dramatic and consistent seasonal changes occurred in the crown, at levels 17–65 times
higher than in the root. Predominant among crown cytokinins was ZR, except in the needles where IPR was also prominent. Within
the crown, cytokinin profiles in different organs differed consistently. The leader bud showed a pronounced mid-June minimum,
and a maximum later in summer. Subapical buds showed the same June minimum but peaked in mid autumn at a much lower level.
Maxima in these buds were preceded by peaks in the subapical stem. Parallel patterns were observed in homologous tissues on
branches.This pattern is consistent with two surges beginning in the uppermost stem tissues leading to subsequent accumulation
or stimulated production within the buds. Strong differential hormonal profiles between adjacent buds with different fates
agree with recent evidence of localized cytokinin production. The data suggest a reduced role of root-derived cytokinins in
crown development. Practical cytokinin treatments for crown-shape regulation require close attention to dosage as well as
precise timing and positioning. 相似文献
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87.
The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure reliable results. Current methods of protein staining for 2D-PAGE, protein labelling for two-dimensional difference gel electrophoresis, gel-based expression analysis and protein identification by MS are summarised. The uses of gel-free MS-based strategies (MuDPIT, iTRAQ, ICAT and SILAC) are also discussed. Proteomic technologies promise to shed new light onto ocular disease processes that could lead to the discovery of strong novel biomarkers and therapeutic targets useful in many ophthalmic conditions. 相似文献
88.
Synthesis and biological evaluation of novel PDMP analogues 总被引:1,自引:0,他引:1
Hillaert U Boldin-Adamsky S Rozenski J Busson R Futerman AH Van Calenbergh S 《Bioorganic & medicinal chemistry》2006,14(15):5273-5284
A new series of hybrid PDMP analogues, based both on PDMP and styryl analogues of natural ceramide, has been synthesized from D-serine. The synthetic route was developed such that future introduction of different aryl groups is straightforward. Biological evaluation, both in vitro on rat liver Golgi fractions as well as in HEK-293 and COS-7 cells, revealed two lead compounds with comparable inhibitory potency as PDMP, which could be elaborated to more potent inhibitors. 相似文献
89.
Synthesis, dopamine and serotonin transporter binding affinities of novel analogues of meperidine 总被引:1,自引:0,他引:1
Lomenzo SA Izenwasser S Gerdes RM Katz JL Kopajtic T Trudell ML 《Bioorganic & medicinal chemistry letters》1999,9(23):3273-3276
A series of meperidine analogues was synthesized and the binding affinities for the dopamine and serotonin transporters were determined. The substituents on the phenyl ring greatly influenced the potency and selectivity of these compounds for the transporter binding sites. In general, meperidine (3) and its analogues were more selective for serotonin transporter binding sites and the esters 9 were more potent than the corresponding nitriles 8. The 3,4-dichloro derivative 9e was the most potent ligand of the series for dopamine transporter binding sites while the 2-naphthyl derivative 9g exhibited the most potent binding affinity and was highly selective for serotonin transporter binding sites. 相似文献
90.