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61.
62.
Carin I. Jarl Gunnel M. Karlsson Janet F. Bornman Chris H. Bornman 《In vitro cellular & developmental biology. Plant》1994,30(1):4-9
Summary The production of hybrid seed is facilitated if one parent possesses a male-sterile cytoplasm. Introduction of the cytoplasm
of male-sterile radish (Raphanus sativus L.) into rapeseed (Brassica napus L.) results not only in transfer of the desirable male-sterile trait but induces a chlorophyll defect in the backcrossed
male-sterile plants. In this study we show that the defect manifests itself in two different ways in the alloplasmic plants:
a) smaller and fewer chloroplasts with an impaired ultrastructure and b) an increase in chlorophyll fluorescence. Defective
chloroplasts were characterized by a reduction in both the number and size of grana, the latter due to poor stacking of thylakoids
and with frequent discontinuity in the intergranal thylakoid systems. The changed chloroplast morphology and the increase
in chlorophyll fluorescence are probably the cause of the lowered photosynthetic efficiency associated with the alloplasmic
plants. We propose that the deficiency is the result of incompatibility between the genomes of the radish chloroplast and
the rapeseed nucleus. Supporting this hypothesis are studies of male-sterile rapeseed plants in which, by protoplast fusion,
the radish chloroplasts were substituted by those of normal male-fertile rapeseed. Such plants showed complete restoration
of their photosynthetic potential and displayed both normal chloroplast ultrastructure and normal levels of chlorophyll fluorescence. 相似文献
63.
Zusammenfassung In Extrakten wachsender Kulturen von Acanthamoeba castellanii konnte ein cellulose-abbauendes Enzymsystem nachgewiesen werden. Es besteht aus einer reduzierende Zucker abspaltenden Komponente mit einem pH-Optimum bei 4, einer viscositätsverändernden Komponente mit einem pH-Optimum bei 6 und einer -Glucosidase mit einem pH-Optimum von 3,5. Bei pH 4 sind die Celluloseabbauprodukte Cellobiose und Glucose, bei pH 6 höhermolekulare Oligosaccharide.Während der Entwicklung in einem nährstofffreien Salzmedium nehmen die Cellulaseaktivitäten ab: Vor dem Start der Cellulosesynthese sind noch etwa 30% der ursprünglich vorhandenen Celluloseaktivität nachzuweisen, fertige Cysten besitzen noch etwa 10% der Aktivität.Die Bedeutung des Cellulassenzymsystems wird ausgehend von der Tatsache diskutiert, daß die Excystierung ohne Abbau der Cystenwand, in die die Cellulose eingelagert ist, stattfindet.
The cellulase enzymes system during growth and development of Acanthamoeba castellanii
It could be shown that extracts of growing cultures of Acanthamoeba castellanii contained a cellulose degrading system. Reducing sugars are split off by one component of this system at an optimum of pH 4, another enzyme changes the viscosity at an optimum of pH 6, and a third component is a -glucosidase with an optimum at pH 3.5. At pH 4 the cellulose degradation products are cellobiose and glucose; at pH 6 higher molecular weight oligosaccharides are produced.During the development from trophozoites to cysts in a nutrient-free medium, the activities of both cellulases decline: Prior to the start of cellulose synthesis only 30%, and in cysts only 10% of the original existing activities are detectable.The biological function of the cellulase enzyme system is discussed together with a consideration of the fact that excystment takes place without digestion of the cyst wall in which the cellulose is deposited.相似文献
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Thomas Alderliesten Laurent M. A. Favie Robert W. Neijzen Volker Auw?rter Cora H. A. Nijboer Roland E. J. Marges Carin M. A. Rademaker Jürgen Kempf Frank van Bel Floris Groenendaal 《PloS one》2014,9(12)
MethodsEight newborn piglets (weight 1.4–3.0 kg) were used. Heart rate, blood pressure, regional cerebral saturation, and electrocortical brain activity were measured continuously. All experiments had a 30 min. baseline period, followed by three 60 min. periods of argon ventilation alternated with 30 min argon washout periods. Two animals were ventilated with increasing concentrations of argon (1h 30%, 1 h 50%, and 1 h 80%), two were subjected to 60 min. hypoxia (FiO2 0.08) before commencing 50% argon ventilation, and two animals received hypothermia following hypoxia as well as 50% argon ventilation. Two animals served as home cage controls and were terminated immediately.ResultsArgon ventilation did not result in a significant change of heart rate (mean ± s.d. −3.5±3.6 bpm), blood pressure (−0.60±1.11 mmHg), cerebral oxygen saturation (0.3±0.9%), electrocortical brain activity (−0.4±0.7 µV), or blood gas values. Argon ventilation resulted in elevated argon concentrations compared to the home cage controls (34.5, 25.4, and 22.4 vs. 7.3 µl/ml).ConclusionVentilation with up to 80% argon during normoxia, and 50% argon after hypoxia did not affect heart rate, blood pressure, cerebral saturation and electrocortical brain activity. Clinical safety studies of argon ventilation in humans seem justified. 相似文献
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Tobias Backström Eva Brännäs Jan Nilsson Hanna Carlberg Kajsa Johansson Carin Magnhagen 《Journal of fish biology》2021,98(4):1192-1195
Carotenoid pigmentation in Salvelinus alpinus has been connected to stress responsiveness in earlier studies. This has, however, only been tested with time-consuming image analysis from photos. Here, we used quick visual categorization of carotenoid pigmentation to investigate the stress responsiveness of the extreme groups. The visually selected charr were then exposed to a net restraint stressor. Arctic charr with few spots also had a lower stress responsiveness compared to charr with many spots. Thus, visual selection could be used as a simple method within aquaculture. 相似文献
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Stephan?C?A?WensEmail author Carin?M?van Gelder Michelle?E?Kruijshaar Juna?M?de Vries Nadine?A?M?E?van der Beek Arnold?J?J?Reuser Pieter?A?van Doorn Ans?T?van der Ploeg Esther?Brusse 《Orphanet journal of rare diseases》2013,8(1):182