全文获取类型
收费全文 | 497篇 |
免费 | 29篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 23篇 |
2014年 | 27篇 |
2013年 | 33篇 |
2012年 | 37篇 |
2011年 | 27篇 |
2010年 | 28篇 |
2009年 | 21篇 |
2008年 | 27篇 |
2007年 | 27篇 |
2006年 | 18篇 |
2005年 | 21篇 |
2004年 | 13篇 |
2003年 | 17篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 9篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1967年 | 2篇 |
1853年 | 2篇 |
1852年 | 17篇 |
排序方式: 共有526条查询结果,搜索用时 31 毫秒
101.
Y. Rumpler S. Warter M. Hauwy B. Meier A. Peyrieras R. Albignac J. J. Petter B. Dutrillaux 《American journal of primatology》1995,36(3):239-244
A cytogenetic study of a female Allocebus trichotis was conducted using R-, G-, and C-banding. Its karyotype does not differ from those of the other Cheirogaleinae (Microcebus, Cheirogaleus, and Mirza). The absence of chromosomal rearrangement in speciation in this group is discussed. © 1995 Wiley-Liss, Inc. 相似文献
102.
Mikael Åkesson Linn Svensson Øystein Flagstad Petter Wabakken Jens Frank 《The Journal of wildlife management》2022,86(4):e22206
Large carnivores are elusive and use large areas, which causes monitoring to be challenging and costly. Moreover, management to reduce conflicts and simultaneously ensure long-term population viability require precise population estimates. In Scandinavia, the monitoring of wolves (Canis lupus) is primarily based on counting packs, identifying reproduction, and genetically identifying territorial wolves from noninvasive DNA samples. We assessed the reliability of wolf monitoring in Scandinavia by estimating the detectability of territorial pairs, packs, and reproduction. Our data, comprising snow-tracking data and DNA-identified individuals from 2005–2016, covered 11 consecutive winter monitoring seasons (Oct–Mar). Among 343 cases where we identified a wolf pack, territorial wolves were also detected in the same area during the previous season in 323 (94.2%) cases. In only 6 of the remaining 20 cases, there was no prior knowledge of territorial wolves in the area. Among the 328 detected reproduction events (litter born to a pack), we detected 97% during the monitoring period and identified the rest ≥1 year later from kinship assessments of all DNA-detected individuals. These results suggest that we failed to detect only few packs with reproduction events during the monitoring season that followed breeding. Yearly monitoring of territorial individuals and continuous updates of the pedigree allowed us to retrospectively identify reproduction events and packs that were not identified earlier. 相似文献
103.
Faergestad EM Rye M Walczak B Gidskehaug L Wold JP Grove H Jia X Hollung K Indahl UG Westad F van den Berg F Martens H 《Proteomics》2007,7(19):3450-3461
A novel approach for revealing patterns of proteome variation among series of 2-DE gel images is presented. The approach utilises image alignment to ensure that each pixel represents the same information across all gels. Gel images are normalised, and background corrected, followed by unfolding of the images to 1-D pixel vectors and analysing pixel vectors by multivariate data modelling. Information resulting from the data analysis is refolded back to the image domain for visualisation and interpretation. The method is rapid and suitable for automatic routines applied after the gel alignment. The approach is compared with spot volume analysis to illustrate how this approach can solve persistent problems like mismatch of protein spots, erroneous missing values and failure to detect variation in overlapping proteins. The method may also detect variation in the border area of saturated proteins. The approach is given the name pixel-based analysis of multiple images for the identification of changes (PMC). The method can be used for multiple images in general. Effects of pretreatment of the images are discussed. 相似文献
104.
Oivind J Kanavin Berit Woldseth Egil Jellum Bjorn Tvedt Brage S Andresen Petter Stromme 《Journal of medical case reports》2007,1(1):1-5
Pulmonary emphysema and bronchiectasis in HIV seropositive patients has been described in the presence of injection drug use, malnutrition, repeated opportunistic infections, such as Pneumocytis jirovici pneumonia and Mycobacterium tuberculosis infection, and has been linked to the presence of HIV virus in lung tissue. Given the high burden of pulmonary infections and malnutrition among people living with HIV in resource poor settings, these individuals may be at increased risk of developing pulmonary emphysema, potentially reducing the long term benefit of antiretroviral therapy (ART) if initiated late in the course of HIV infection. In this report, we describe three HIV-infected individuals (one woman and two children) presenting with extensive pulmonary cystic disease. 相似文献
105.
Stefan Drie?en Niklas Berleth Olena Friesen Antje S L?ffler Philip B?hler Nora Hieke Fabian Stuhldreier Christoph Peter Kay O Schink Sebastian W Schultz Harald Stenmark Petter Holland Anne Simonsen Sebastian Wesselborg Bj?rn Stork 《Autophagy》2015,11(9):1458-1470
Autophagy represents an intracellular degradation process which is involved in both regular cell homeostasis and disease settings. In recent years, the molecular machinery governing this process has been elucidated. The ULK1 kinase complex consisting of the serine/threonine protein kinase ULK1 and the adapter proteins ATG13, RB1CC1, and ATG101, is centrally involved in the regulation of autophagy initiation. This complex is in turn regulated by the activity of different nutrient- or energy-sensing kinases, including MTOR, AMPK, and AKT. However, next to phosphorylation processes it has been suggested that ubiquitination of ULK1 positively influences ULK1 function. Here we report that the inhibition of deubiquitinases by the compound WP1130 leads to increased ULK1 ubiquitination, the transfer of ULK1 to aggresomes, and the inhibition of ULK1 activity. Additionally, WP1130 can block the autophagic flux. Thus, treatment with WP1130 might represent an efficient tool to inhibit the autophagy-initiating ULK1 complex and autophagy. 相似文献
106.
Nora Hieke Antje S L?ffler Takeshi Kaizuka Niklas Berleth Philip B?hler Stefan Drie?en Fabian Stuhldreier Olena Friesen Kaivon Assani Katharina Schmitz Christoph Peter Britta Diedrich J?rn Dengjel Petter Holland Anne Simonsen Sebastian Wesselborg Noboru Mizushima Bj?rn Stork 《Autophagy》2015,11(9):1471-1483
Autophagy describes an intracellular process responsible for the lysosome-dependent degradation of cytosolic components. The ULK1/2 complex comprising the kinase ULK1/2 and the accessory proteins ATG13, RB1CC1, and ATG101 has been identified as a central player in the autophagy network, and it represents the main entry point for autophagy-regulating kinases such as MTOR and AMPK. It is generally accepted that the ULK1 complex is constitutively assembled independent of nutrient supply. Here we report the characterization of the ATG13 region required for the binding of ULK1/2. This binding site is established by an extremely short peptide motif at the C terminus of ATG13. This motif is mandatory for the recruitment of ULK1 into the autophagy-initiating high-molecular mass complex. Expression of a ULK1/2 binding-deficient ATG13 variant in ATG13-deficient cells resulted in diminished but not completely abolished autophagic activity. Collectively, we propose that autophagy can be executed by mechanisms that are dependent or independent of the ULK1/2-ATG13 interaction. 相似文献
107.
Gervasi V Nilsen EB Sand H Panzacchi M Rauset GR Pedersen HC Kindberg J Wabakken P Zimmermann B Odden J Liberg O Swenson JE Linnell JD 《The Journal of animal ecology》2012,81(2):443-454
1. Understanding the role of predation in shaping the dynamics of animal communities is a fundamental issue in ecological research. Nevertheless, the complex nature of predator-prey interactions often prevents researchers from modelling them explicitly. 2. By using periodic Leslie-Usher matrices and a simulation approach together with parameters obtained from long-term field projects, we reconstructed the underlying mechanisms of predator-prey demographic interactions and compared the dynamics of the roe deer-red fox-Eurasian lynx-human harvest system with those of the moose-brown bear-gray wolf-human harvest system in the boreal forest ecosystem of the southern Scandinavian Peninsula. 3. The functional relationship of both roe deer and moose λ to changes in predation rates from the four predators was remarkably different. Lynx had the strongest impact among the four predators, whereas predation rates by wolves, red foxes, or brown bears generated minor variations in prey population λ. Elasticity values of lynx, wolf, fox and bear predation rates were -0·157, -0·056, -0·031 and -0·006, respectively, but varied with both predator and prey densities. 4. Differences in predation impact were only partially related to differences in kill or predation rates, but were rather a result of different distribution of predation events among prey age classes. Therefore, the age composition of killed individuals emerged as the main underlying factor determining the overall per capita impact of predation. 5. Our results confirm the complex nature of predator-prey interactions in large terrestrial mammals, by showing that different carnivores preying on the same prey species can exert a dramatically different demographic impact, even in the same ecological context, as a direct consequence of their predation patterns. Similar applications of this analytical framework in other geographical and ecological contexts are needed, but a more general evaluation of the subject is also required, aimed to assess, on a broader systematic and ecological range, what specific traits of a carnivore are most related to its potential impact on prey species. 相似文献
108.
Sigve Nakken Morten Johansen Julien Fillebeen Ole Petter Berge Harald Kirker?d Tor-Kristian Jenssen Eivind Hovig 《Bioinformation》2012,8(22):1119-1122
Experimental models of human tissues and disease phenotypes frequently rely upon immortalized cell lines, which are easily
accessible and simple to use due to their infinite capability of cell division. For decades, cell lines have been used to investigate
cellular mechanisms of disease and the efficacy of drugs, most prominently for human cancers. However, the large body of
knowledge with respect to human cell lines exists primarily in an unstructured fashion, that is, as free text in the scientific
literature. Here we present CellLineMiner, a novel text mining-based web database that provides a comprehensive view of human
cell line knowledge. The application offers a simple search in all indexed cell lines, accompanied by a rapid display of all identified
literature associations. The CellLineMiner is intended to serve as a knowledge resource companion to the cellular model systems
used in biomedical research.
Availability
CellLineMiner is accessible at http://dev.pubgene.com/cellmine 相似文献109.
Grant Murray Barbara Neis Jahn Petter Johnsen 《Human ecology: an interdisciplinary journal》2006,34(4):549-571
Questions centered on the development of local and traditional ecological knowledge and the relationship of that knowledge to the development of conservation and management practices have recently attracted critical attention. We examine these questions with respect to the dynamic commercial fisheries of the Canadian province of Newfoundland and Labrador. The knowledge of fish harvesters coevolves with fishing practices and is embedded in a dynamic socioecological network that extends into and beyond the fisher, fishery households, and communities to include management, technologies, markets, and marine ecological conditions. Changes in these networks have moved knowledge and practices related to fishing in directions defined by policy, science, economic rationality, and new ecological realities. We characterize this movement as a shift along a continuum from local ecological knowledge (LEK) towards globalized harvesting knowledge (GHK) as harvesters become increasingly disconnected from socioecological relationships associated with traditional species and stocks. We conclude with a discussion of how LEK/GHK have interacted over time and space with other knowledge systems (particularly science) to influence management, and suggest that contingent, empirical evaluations of these interactions will provide a fruitful avenue for future interdisciplinary research.
相似文献
Grant MurrayEmail: |
110.
Entringer PF Gondim KC Meyer-Fernandes JR 《Archives of insect biochemistry and physiology》2006,61(1):1-9
In this study, we describe the ability of intact fat body of an insect, Rhodnius prolixus, to hydrolyze extracellular ATP. In these fat bodies, the ATP hydrolysis was low in the absence of any divalent metal, and was stimulated by MgCl(2). Both activities (in the absence or presence of MgCl(2)) were linear with time for at least 30 min. In order to confirm the observed nucleotidase activities as ecto-nucleotidases, we used an impermeant inhibitor, DIDS (4, 4'-diisothiocyanostylbene 2'-2'-disulfonic acid). This reagent inhibited both nucleotidase activities and its inhibitory effect was suppressed by ATP. Both ecto-nucleotidase activities were insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin, ouabain, vanadate, molybdate, sodium fluoride, levamizole, tartrate, p-NPP, sodium phosphate, and suramin. Concanavalin A, activator of some ecto-ATPases, was able to stimulate the Mg(2+)-independent nucleotidase activity, but not the Mg(2+)-dependent one. The Mg(2+)-independent nucleotidase activity was enhanced with increases in the pH in the range between 6.4-8.0, but the Mg(2+)-dependent nucleotidase activity was not affected. Besides MgCl(2) , the ecto-ATPase activity was also stimulated by CaCl(2),() MnCl(2), and SrCl(2), but not by ZnCl(2). ATP, ADP, and AMP were the best substrates for the Mg(2+)-dependent ecto-nucleotidase activity, and CTP, GTP, and UTP produced very low reaction rates. However, the Mg(2+)-independent nucleotidase activity recognized all these nucleotides producing similar reaction rates, but GTP was a less efficient substrate. The possible role of the two ecto-nucleotidase activities present on the cell surface of fat body of Rhodnius prolixus, which are distinguished by their substrate specificity and their response to Mg(2+), is discussed. 相似文献