全文获取类型
收费全文 | 648篇 |
免费 | 51篇 |
专业分类
699篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 12篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 18篇 |
2015年 | 31篇 |
2014年 | 39篇 |
2013年 | 36篇 |
2012年 | 43篇 |
2011年 | 48篇 |
2010年 | 26篇 |
2009年 | 25篇 |
2008年 | 41篇 |
2007年 | 33篇 |
2006年 | 23篇 |
2005年 | 33篇 |
2004年 | 29篇 |
2003年 | 26篇 |
2002年 | 38篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1973年 | 6篇 |
1965年 | 3篇 |
1963年 | 4篇 |
1959年 | 2篇 |
1956年 | 2篇 |
1950年 | 2篇 |
1949年 | 4篇 |
排序方式: 共有699条查询结果,搜索用时 0 毫秒
11.
Annemarie Plessl 《Plant Systematics and Evolution》1963,110(2-3):194-269
Ohne ZusammenfassungEin Teil der vorliegenden Untersuchungen wurde stark gekürzt schon 1949 veröffentlicht (siehe das Literaturverzeichnis). Wie die Entwicklung der Lichenologie in den folgenden Jahren zeigte, haben diese umfangreichen Untersuchungen nichts an Aktualität verloren, vielmehr gewonnen, und 相似文献
12.
Ohne Zusammenfassung 相似文献
13.
Ohne Zusammenfassung 相似文献
14.
Willem‐Jan Emsens Lennart Suselbeek Ben T. Hirsch Roland Kays Annemarie J. S. Winkelhagen Patrick A. Jansen 《Biotropica》2013,45(1):88-93
Animals that rely on refuges for safety can theoretically increase their foraging area without simultaneously increasing predation risk and travel costs by using more refuges. The key prediction of this theory, a negative correlation between food abundance, home range size and the number of refuges used, has never been empirically tested. We determined how home range size and refuge use by the Central American agouti (Dasyprocta punctata) varied across a gradient of abundance of the agoutis' principal food source: seeds and fruits of the palm Astrocaryum standleyanum. We used both manual and automated radio telemetry to measure space use of 11 agoutis during 2 mo of the Astrocaryum fruiting season, and of another set of 10 agoutis during 6 mo in which the animals largely relied on cached Astrocaryum seeds. We found that agoutis living in areas of lower food density had larger home ranges, and that all individuals used multiple refuges. The number of refuges, however, was not correlated with home range size. Consequently, agoutis that had larger home ranges roamed farther from their refuges. These results suggest that agoutis increase their home range size in response to food scarcity at the cost of their safety. 相似文献
15.
Annemarie Voorberg-van der Wel Anne-Marie Zeeman Sandra M. van Amsterdam Alexander van den Berg Els J. Klooster Shiroh Iwanaga Chris J. Janse Geert-Jan van Gemert Robert Sauerwein Niels Beenhakker Gerrit Koopman Alan W. Thomas Clemens H. M. Kocken 《PloS one》2013,8(1)
A major challenge for strategies to combat the human malaria parasite Plasmodium vivax is the presence of hypnozoites in the liver. These dormant forms can cause renewed clinical disease after reactivation through unknown mechanisms. The closely related non-human primate malaria P. cynomolgi is a frequently used model for studying hypnozoite-induced relapses. Here we report the generation of the first transgenic P. cynomolgi parasites that stably express fluorescent markers in liver stages by transfection with novel DNA-constructs containing a P. cynomolgi centromere. Analysis of fluorescent liver stages in culture identified, in addition to developing liver-schizonts, uninucleate persisting parasites that were atovaquone resistant but primaquine sensitive, features associated with hypnozoites. We demonstrate that these hypnozoite-forms could be isolated by fluorescence-activated cell sorting. The fluorescently-tagged parasites in combination with FACS-purification open new avenues for a wide range of studies for analysing hypnozoite biology and reactivation. 相似文献
16.
Marion Herens Evert Jan Bakker Johan van Ophem Annemarie Wagemakers Maria Koelen 《PloS one》2016,11(2)
Physical inactivity is most commonly found in socially vulnerable groups. Dutch policies target these groups through community-based health-enhancing physical activity (CBHEPA) programs. As robust evidence on the effectiveness of this approach is limited, this study investigated whether CBHEPA programs contribute to an increase in and the maintenance of physical activity in socially vulnerable groups. In four successive cohorts, starting at a six-month interval, 268 participants from 19 groups were monitored for twelve months in seven CBHEPA programs. Data collection was based on repeated questionnaires. Socio-economic indicators, program participation and coping ability were measured at baseline. Physical activity, health-related quality of life and on-going program participation were measured three times. Self-efficacy and enjoyment were measured at baseline and at twelve months. Statistical analyses were based on a quasi-RCT design (independent t-tests), a comparison of participants and dropouts (Mann-Whitney test), and multilevel modelling to assess change in individual physical activity, including group level characteristics. Participants of CBHEPA programs are socially vulnerable in terms of low education (48.6%), low income (52.4%), non-Dutch origin (64.6%) and health-related quality of life outcomes. Physical activity levels were not below the Dutch average. No increase in physical activity levels over time was observed. The multilevel models showed significant positive associations between health-related quality of life, self-efficacy and enjoyment, and leisure-time physical activity over time. Short CBHEPA programs (10–13 weeks) with multiple trainers and gender-homogeneous groups were associated with lower physical activity levels over time. At twelve months, dropouts'' leisure-time physical activity levels were significantly lower compared to continuing participants, as were health-related quality of life, self-efficacy and enjoyment outcomes. BMI and care consumption scored significantly higher among dropouts. In conclusion, Dutch CBHEPA programs reach socially vulnerable, but not necessarily inactive, groups in terms of socio-economic and health-related quality of life outcomes. Our findings suggest that CBHEPA programs particularly contribute to physical activity maintenance in socially vulnerable groups, rather than to an increase in physical activity behaviour over time. 相似文献
17.
Basic Domains Target Protein Subunits of the RNase MRP Complex to the Nucleolus Independently of Complex Association 总被引:6,自引:0,他引:6 下载免费PDF全文
Hans van Eenennaam Annemarie van der Heijden Rolf J. R. J. Janssen Walther J. van Venrooij Ger J. M. Pruijn 《Molecular biology of the cell》2001,12(11):3680-3689
The RNase MRP and RNase P ribonucleoprotein particles both function as endoribonucleases, have a similar RNA component, and share several protein subunits. RNase MRP has been implicated in pre-rRNA processing and mitochondrial DNA replication, whereas RNase P functions in pre-tRNA processing. Both RNase MRP and RNase P accumulate in the nucleolus of eukaryotic cells. In this report we show that for three protein subunits of the RNase MRP complex (hPop1, hPop4, and Rpp38) basic domains are responsible for their nucleolar accumulation and that they are able to accumulate in the nucleolus independently of their association with the RNase MRP and RNase P complexes. We also show that certain mutants of hPop4 accumulate in the Cajal bodies, suggesting that hPop4 traverses through these bodies to the nucleolus. Furthermore, we characterized a deletion mutant of Rpp38 that preferentially associates with the RNase MRP complex, giving a first clue about the difference in protein composition of the human RNase MRP and RNase P complexes. On the basis of all available data on nucleolar localization sequences, we hypothesize that nucleolar accumulation of proteins containing basic domains proceeds by diffusion and retention rather than by an active transport process. The existence of nucleolar localization sequences is discussed. 相似文献
18.
Molecular clones of the mouse t complex derived from microdissected metaphase chromosomes 总被引:27,自引:0,他引:27
Dan Röhme Howard Fox Bernhard Herrmann Anna-Maria Frischauf Jan-Erik Edström Paul Mains Lee M. Silver Hans Lehrach 《Cell》1984,36(3):783-788
Fragments of the proximal half of mouse chromosome 17 including the t-complex region were microdissected from metaphase spreads. DNA was isolated from a pool of such fragments, and was cloned on microscale. Individual clones were used to probe genomic digests of DNA from a pair of Chinese hamster cell lines with or without mouse chromosome 17, and livers of congenic inbred lines of mice carrying wild-type and/or t-haplotype forms of chromosome 17. The data obtained indicate that 95% of the low copy number microclone inserts recognize DNA sequences present on mouse chromosome 17. It has been possible to use one-third of these clones to identify restriction-fragment-length polymorphisms between wild-type and t-haplotype DNA on a congenic background. These results demonstrate that these clones have been derived from the t-complex or regions closely linked to it. Clones of this type should provide starting points for a molecular analysis of this region of the mouse genome. 相似文献
19.
Ronald Bontrop Marcel Tilanus Marlies Mikulski Marja van Eggermond Annemarie Termijtelen Marius Giphart 《Immunogenetics》1986,23(6):401-405
HLA-DR molecules were isolated from eight different HLA-DR3 homozygous B-cell lines by immunoprecipitation with monoclonal antibodies, and they were subsequently analyzed by two-dimensional gel electrophoresis. We found that HLA-DR3 homozygous B-cell lines of consanguineous origin express two types of HLA-DR molecules. One type of HLA-DR molecule was present in all the cell lines tested, whereas the second DR molecule appears to be polymorphic. DNA isolated from the different HLA-DR3 homozygous cell lines was studied by Southern blot analysis to determine whether any DR restriction fragment length polymorphism could be observed. Polymorphisms detected at both the product and genomic level have been compared to each other, and their relations to the serological (HLA-DR) and cellular (HLA-D and LB-Q1) typing data will be discussed.No reprints available 相似文献
20.
Thomas F. Holzman Christine C. Chung Rohinton Edalji David A. Egan Earl J. Gubbins Annemarie Rueter Gail Howard Lana K. Yang Terry M. Pederson Grant A. Krafft et al. 《Journal of Protein Chemistry》1990,9(6):663-672
The gene for human preprorenin was obtained from total RNA prepared from primary human chorion cells. An expression vector was constructed containing an SV40 early promoter, a human preprorenin cDNA, bovine growth hormone poly-A addition signal, and a dihydrofolate reductase (dhfr) expression cassette. This vector was inserted into the DXB-11 Chinese hamster ovary (CHO) cell line. The recombinant protein was exported by CHO cells into the tissue culture media. At harvest the prorenin levels ranged from 1–5 mg/L. For prorenin isolation the cell culture supernatants were processed by filtration, concentration, dialysis, and batch extraction. Preparative-scale isolation of prorenin was accomplished using blue-dye chromatography and size-exclusion chromatography. The isolated prorenin yielded a single SDS-gel band with Mr 40,000. The proprotein was characterized with respect to N-terminal sequence and N-linked sugar composition. Trypsin-activated renin prepared from the proprotein was characterized with respect to N-terminal sequence andpH-activity profile. Enzyme activity was measured with a newly developed fluorogenic peptide substrate containing the P6-P3 sequence of human angiotensinogen. 相似文献