全文获取类型
收费全文 | 198篇 |
免费 | 21篇 |
出版年
2023年 | 1篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 12篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 13篇 |
2011年 | 12篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 13篇 |
2006年 | 13篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 13篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1934年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 437 毫秒
81.
82.
Jens Jørgen Christensen Peter Gerner-Smidt Brita Bruun 《FEMS immunology and medical microbiology》1995,12(1):43-46
Abstract Restriction enzyme analysis typing with Hin fI, Hae III and Pst I was performed on Moraxella (Branhamella) catarrhalis strains consecutively collected from children suspected of respiratory tract infection and the type strain. Use of Hin fI gave the most distinct patterns. Great polymorphism was seen among strains. 相似文献
83.
J. Nielsen G. Bruun Petersen A. J. Therkelsen Kirsten Riber Christensen Gudrun Dahl Ursula Friedrich Anders Frøland Petrea Jacobsen Mogens Krogh-Jensen Margareta Mikkelsen Jan Mohr Erik Niebuhr John Philip Jørgen Schultz-Larsen Niels Skakkebæk Jacob Visfeldt Eva Zeuthen 《Human genetics》1973,19(1):67-74
Summary The seasonal variation in frequency of birth of 297 patients with karyotypes 47,XXY, 47,XYY, 47,XXX and 45,X registered in the Danish Cytogenetic Central Register until January 1st, 1971, was significantly different from the variation expected. The frequency of conception was higher than expected in June, July and August and lower in September, October and December. The variation in frequency of birth of the 791 patients with trisomy 21 was not significantly different from the expected value.There was no coincidence between the peak frequency of conception of children with aneuploid sex chromosome abnormalities and the peak frequency of a number of infectious diseases.It is concluded that the cause of the seasonal variation in frequency of conception and birth of children with aneuploid sex chromosome abnormalities is unknown. A number of possible factors are mentioned.
Zusammenfassung Bei den 297 Patienten mit Karyotypen 47,XXY, 47,XYY, 47,XXX und 45,X, die bis zum 1. Januar 1971 im Dänischen Cytogenetischen Centralergister registriert worden sind, unterschied sich die jahreszeitliche Variation in der Geburtenhäufigkeit signifikant von der erwarteten Variation. Die Konzeptionshäufigkeit war in den Monaten Juni, Juli und August erhöht und im September, Oktober und Dezember erniedrigt, wohingegen die Variation in der Geburtenhäufigkeit von 791 Patienten mit Karyotypen 47,XX order XY,+21 Abnormitäten nicht signifikant unterschiedlich von der erwarteten Variation war.Es fand sich kein Zusammentreffen zwischen dem Häufigkeitsgipfel der Konzeption von Kindern mit aneuploiden Geschlechtschromosomenabnormitäten und dem Gipfel einer Reihe von Infektionskrankheiten.Daraus wird geschlossen, daß die Ätiologie der jahreszeitlichen Variation der Konzeptions-häufigkeit und Geburten von Kindern mit aneuploiden Geschlechtschromosomenabnormitäten unbekannt ist. Eine Reihe möglicher Faktoren wird erwähnt.相似文献
84.
Torger Bruun 《Phytochemistry》1976,15(8):1261-1263
The presence of free fatty acids in Cetraria nivalis and Cladonia gonecha has been demonstrated. Saturated wax esters occur in Cetraria cucullata and C. nivalis, whilst free alkanols were found in C. cucullata. Triglycerides in C. nivalis were detected by their MS fragmentation patterns. Hexa(α-hydroxyisovalerate) is present in C. nivalis and Cl. gonecha, and the presence of ribitol in C. nivalis was demonstrated by identification of its acetonide in an acetone extract. 相似文献
85.
Are ungulates in forests concerns or key species for conservation and biodiversity? Reply to Boulanger et al. (DOI: 10.1111/gcb.13899)
下载免费PDF全文
![点击此处可从《Global Change Biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
86.
Competition between folding and glycosylation in the endoplasmic reticulum. 总被引:6,自引:0,他引:6
下载免费PDF全文
![点击此处可从《The EMBO journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Using carboxypeptidase Y in Saccharomyces cerevisiae as a model system, the in vivo relationship between protein folding and N-glycosylation was studied. Seven new sites for N-glycosylation were introduced at positions buried in the folded protein structure. The level of glycosylation of such new acceptor sites was analysed by pulse-labelling under two sets of conditions that are known to reduce the rate of folding: (i) addition of dithiothreitol to the growth medium and (ii) introduction of deletions in the propeptide. A variety of effects was observed, depending on the position of the new acceptor sites. In some cases, all the newly synthesized mutant protein was modified at the novel site while in others no modification took place. In the most interesting category of mutants, the level of glycosylation was dependent on the conditions for folding. This shows that folding and glycosylation reactions can compete in vivo and that glycosylation does not necessarily precede folding. The approach described may be generally applicable for the analysis of protein folding in vivo. 相似文献
87.
Functional complementation by electroporation of human BACs into mammalian fibroblast cells. 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J A Hejna P L Johnstone S L Kohler D A Bruun C A Reifsteck S B Olson R E Moses 《Nucleic acids research》1998,26(4):1124-1125
Bacterial Artificial Chromosomes (BACs) have been used to complement a metabolic defect and to transfer a drug resistance marker into mammalian cells by electroporation. The selectable markers are stable and the recipient cells have BAC DNA integrated into the chromosomes as shown by fluorescent in situ hybridization, PCR and Southern hybridization. 相似文献
88.
Wibke Christel Sander Bruun Jakob Magid Witold Kwapinski Lars Stoumann Jensen 《Plant and Soil》2016,401(1-2):93-107
Aims
The aim was to study effects of slurry acidification, separation technology and thermal processing on the availability of P in soil amended with the solid fraction of pig slurry.Methods
Acidified and non-acidified slurry were separated using different technologies: screw press (SCR), decanting centrifuge (DEC) and drainage after chemical pretreatment (CHE). Solids and pyrolysed (400 °C or 600 °C, char) or combusted (625 °C, ash) solids were applied to two soils, with triple superphosphate (TSP) as a reference. Soil P availability was determined over 12 weeks using diffusive gradients in thin films (DGT).Results
The initial availability of P from DEC and CHE solids was similar to TSP in both soils. After 6 weeks no significant difference was observed between DEC solids and DEC chars. Acidification did not significantly affect P availability in the solids-amended soils over time, but it did affect P availability with the thermally processed materials.Conclusions
Application of separated pig slurry solids generally increased soil P availability initially, but declining with time, indicating soil P fixing reactions. Chars and ashes on the other hand showed lower initial P availability, but remained constant or increased slightly with chars yielding P availability similar to solids after 12 weeks.89.
Mafalda Resende Sisse B. Ditlev Morten A. Nielsen Silas Bruun Henrik Clausen Thor G. Theander Madeleine Dahlbäck 《International journal for parasitology》2009,39(11):1195-1204
Individuals living in areas with high Plasmodium falciparum transmission acquire immunity to malaria over time and adults have a markedly reduced risk of contracting severe disease. However, pregnant women constitute an important exception. Pregnancy-associated malaria is a major cause of mother and offspring morbidity, such as severe maternal anaemia and low birth-weight, and is characterised by selective accumulation of parasite-infected erythrocytes (IE) in the placenta. A P. falciparum protein named VAR2CSA, which belongs to the large P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) family, enables the IE to bind chondroitin sulphate A (CSA) in the placenta. Knock-out studies have demonstrated the exclusive capacity of VAR2CSA to mediate IE binding to CSA, and it has been shown that four of the six Duffy-binding-like (DBL) domains of VAR2CSA have the ability to bind CSA in vitro. In this study, we confirm the CSA-binding of these DBL domains, however, the analysis of a number of DBL domains of a non-VAR2CSA origin shows that CSA-binding is not exclusively restricted to VAR2CSA DBL domains. Furthermore, we show that the VAR2CSA DBL domains as well as other DBL domains also bind heparan sulphate. These data explain a number of publications describing CSA-binding domains derived from PfEMP1 antigens not involved in placental adhesion. The data suggest that the ability of single domains to bind CSA does not predict the functional capacity of the whole PfEMP1 and raises doubt whether the CSA-binding domains of native VAR2CSA have been correctly identified. 相似文献
90.
Environmental Consequences of the Demise in Swidden Cultivation in Montane Mainland Southeast Asia: Hydrology and Geomorphology 总被引:1,自引:0,他引:1
Alan D. Ziegler Thilde B. Bruun Maite Guardiola-Claramonte Thomas W. Giambelluca Deborah Lawrence Nguyen Thanh Lam 《Human ecology: an interdisciplinary journal》2009,37(3):361-373
The hydrological and geomorphological impacts of traditional swidden cultivation in Montane Mainland Southeast Asia are virtually
inconsequential, whereas the impacts associated with intensified replacement agricultural systems are often much more substantial.
Negative perceptions toward swiddening in general by governments in the region beginning half a decade ago have largely been
based on cases of forest conversion and land degradation associated with (a) intensified swidden systems, characterized by
shortened fallow and extended cropping periods and/or (b) the widespread cultivation of opium for cash after the Second World
War. Neither of these practices should be viewed as traditional, subsistence-based swiddening. Other types of intensive agriculture
systems are now replacing swiddening throughout the region, including semi-permanent and permanent cash cropping, monoculture
plantations, and greenhouse complexes. The negative impacts associated with these systems include changes in streamflow response,
increased surface erosion, a higher probability of landslides, and the declination in stream water quality. Unlike the case
for traditional swiddening, these impacts result because of several factors: (1) large portions of upland catchments are cultivated
simultaneously; (2) accelerated hydraulic and tillage erosion occurs on plots that are cultivated repetitively with limited
or no fallowing to allow recovery of key soil properties, including infiltration; (3) concentrated overland flow and erosion
sources are often directly connected with the stream network; (4) root strength is reduced on permanently converted hillslopes;
(5) surface and ground water extraction is frequently used for irrigation; and (6) and pesticides and herbicides are used.
Furthermore, the commercial success of these systems relies on the existence of dense networks of roads, which are linear
landscape features renowned for disrupting hydrological and geomorphological systems. A new conservation focus is needed to
reduce the impacts of these intensified upland agricultural practices. 相似文献