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61.
JINDŘIŠKA BOJKOVÁ KLÁRA KOMPRDOVÁ TOMÁŠ SOLDÁN SVĚTLANA ZAHRÁDKOVÁ 《Freshwater Biology》2012,57(12):2550-2567
1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area. 相似文献
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目的:研究铼.188标记生物分子在肿瘤治疗中的应用。方法:选取小白鼠作为实验的研究对象,将荷瘤鼠的肉瘤切成小块接种到小白鼠身上,达到试验条件时使用,即将没有明显差异的小白鼠16只随机分为4组,每组4只,注射含有铼一188的药物后分别在不同的时间将其处死,之后取出重要器官进行测量分析,进而得出铼一188的应用效果。结果:瘤内注射的要去在不同时间放射性在瘤内的保持率分别为(90.5±7.7)D%(1h),(92.2±8.6)D%(24h),(88.3±10.9)D%(48h)和(91.5±7.6)D%(72h),在荷瘤鼠内注入生理盐水、非放硫化铼和188Re.硫化铼混悬液,肿瘤质量分别为2885.3±1241.3、2839.9±1965.2和98.4±45.5mg。188Re-硫化铼混悬液在生理盐水、磷酸盐缓冲液和小牛血清中均可稳定72h,而且188W-188Re发生器的应用还可以降低188Re-硫化铼混悬液的价格。随着处死时间的延迟,小鼠肿瘤质量和体积逐渐减小,相临两组比较,后组测定值均明显小于前组,数据经统计学比较具有显著差异(P〈0.05)。结论:188Re-硫化铼混悬液是一种适宜的肿瘤治疗剂。 相似文献
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Background
In August 2006 a major epidemic of bluetongue virus serotype 8 (BTV8) started off in North-West Europe. In the course of 2007 it became evident that BTV8 had survived the winter in North-West Europe, re-emerged and spread exponentially. Recently, the European Union decided to start vaccination against BTV8. In order to improve the understanding of the epidemiological situation, it was necessary to execute a cross-sectional serological study at the end of the BT vector season. Cattle were the target species for cross-sectional serological studies in Europe at the end of 2006 and 2007. However, there was no information on the BTV8-seroprevalence in sheep and goats. 相似文献66.
Stephen A. Diamond Peter C. Trenham Michael J. Adams Blake R. Hossack Roland A. Knapp Stacey L. Stark David Bradford P. Stephen Corn Ken Czarnowski Paul D. Brooks Dan Fagre Bob Breen Naomi E. Detenbeck Kathy Tonnessen 《Ecosystems》2005,8(5):462-477
Ultraviolet-B radiation (UV-B, 280–320-nm wavelengths) doses were estimated for 1024 wetlands in six national parks: Acadia
(Acadia), Glacier (Glacier), Great Smoky Mountains (Smoky), Olympic (Olympic), Rocky Mountain (Rocky), and Sequoia/Kings Canyon
(Sequoia). Estimates were made using ground-based UV-B data (Brewer spectrophotometers), solar radiation models, GIS tools,
field characterization of vegetative features, and quantification of DOC concentration and spectral absorbance. UV-B dose
estimates were made for the summer solstice, at a depth of 1 cm in each wetland. The mean dose across all wetlands and parks
was 19.3 W-h m−2 (range of 3.4–32.1 W-h m−2). The mean dose was lowest in Acadia (13.7 W-h m−2) and highest in Rocky (24.4 W-h m−2). Doses were significantly different among all parks. These wetland doses correspond to UV-B flux of 125.0 μW cm−2 (range 21.4–194.7 μW cm−2) based on a day length, averaged among all parks, of 15.5 h. Dissolved organic carbon (DOC), a key determinant of water-column
UV-B flux, ranged from 0.6 (analytical detection limit) to 36.7 mg C L−1 over all wetlands and parks, and reduced potential maximal UV-B doses at 1-cm depth by 1%–87 %. DOC concentration, as well
as its effect on dose, was lowest in Sequoia and highest in Acadia (DOC was equivalent in Acadia, Glacier, and Rocky). Landscape
reduction of potential maximal UV-B doses ranged from zero to 77% and was lowest in Sequoia. These regional differences in
UV-B wetland dose illustrate the importance of considering all aspects of exposure in evaluating the potential impact of UV-B
on aquatic organisms. 相似文献
67.
Vian Azzu Charles Affourtit Eamon P. Breen Nadeene Parker Martin D. Brand 《BBA》2008,1777(10):1378-1383
Uncoupling protein 2 (UCP2) regulates glucose-stimulated insulin secretion in pancreatic beta-cells. UCP2 content, measured by calibrated immunoblot in INS-1E insulinoma cells (a pancreatic beta-cell model) grown in RPMI medium, and INS-1E mitochondria, was 2.0 ng/million cells (7.9 ng/mg mitochondrial protein). UCP2 content was lower in cells incubated without glutamine and higher in cells incubated with 20 mM glucose, and varied from 1.0-4.4 ng/million cells (2.7-14.5 ng/mg mitochondrial protein). This dynamic response to nutrients was achieved by varied expression rates against a background of a very short UCP2 protein half-life of about 1 h. 相似文献
68.
Andrew B. Kingston Jon Marsden‐Smedley Don A. Driscoll Sib Corbett Janet Fenton Rachel Anderson Cathie Plowman Frances Mowling Margie Jenkin Kiyoshi Matsui Kevin J. Bonham Mick Ilowski Peter B. Mcquillan Belinda Yaxley Tim Reid David Storey Lionel Poole Stephen A. Mallick Nicholas Fitzgerald Jamie B. Kirkpatrick Justin Febey Andrew G. Harwood Karyl F. Michaels Mick J. Russell Paul G. Black Louise Emmerson Mic Ah Visoiu John Morgan Shane Breen Simon Gates Mark N. Bantich Jolyon M. Desmarchelier 《Austral ecology》2002,27(2):162-172
Abstract Observations of the large earth bumblebee, Bombus terrestris (L.), in native vegetation were collated to determine the extent to which this exotic species has invaded Tasmanian native vegetation during the first 9 years after its introduction. The range of B. terrestris now encompasses all of Tasmania's major vegetation types, altitudes from sea level to 1260m a.s.L, and the entire breadth of annual precipitation in the state from more than 3200 mm to less than 600 mm. Observations of workers carrying pollen, together with the presence of large numbers of bumblebees at many localities across this range indicate that colonies are frequently established in native vegetation. Evidence that colonies are often successful was obtained from repeated observations of the species during more than 1 year at particular sites. Unequivocal evidence of colonies was obtained from six National Parks, including four of the five in the Tasmanian Wilderness World Heritage Area (WHA). Indeed, the species has been present in the WHA for at least as long as it has in the city of Hobart, where it was first recorded. In southwestern Tasmania, evidence of colonies was obtained up to 40km from gardens, 61 km from small towns and 93 km from large towns. Hence, contrary to previous suggestions, the species is established in the most remote parts of Tasmania and is not dependent on introduced garden plants. Given their strong record of invasion, it is likely that B. terrestris will form feral populations on the mainland of Australia and in many other parts of the world if introduced. Because of their likely negative impacts on native animals and plants, and potential to enhance seed production in weeds, the spread of bumblebees should be avoided. 相似文献
69.
Kim E. Haworth Ira Islam Matthew Breen Wendy Putt Eleni Makrinou Matthew Binns David Hopkinson Yvonne Edwards 《Mammalian genome》2001,12(8):622-629
We describe the construction of a dog embryonic head/neck cDNA library and the isolation of the dog homolog of the Treacher
Collins Syndrome gene, TCOF1. The protein shows a similar three-domain structure to that described for human TCOF1, but the dog gene lacks exon 10 and
contains two exons not present in the human sequence. In addition, exon 19 is differentially spliced in the dog. How these
structural differences relate to TCOF1 phosphorylation is discussed. Isolation of a genomic clone allowed the exon/intron
boundaries to be characterized and the dog TCOF1 gene to be mapped to CF Chr 4q31, a region syntenic to human Chr 5. Genetic analysis of DNA of dogs from 13 different breeds
identified nine DNA sequence variants, three of which gave rise to amino acid substitutions. Grouping dogs according to head
type showed that a C396T variant, leading to a Pro117Ser substitution, is associated with skull/face shape in our dog panel.
The numbers are small, but the association between the T allele and brachycephaly, broad skull/short face, was highly significant
(p= 0.000024). The short period of time during which the domestic dog breeds have been established suggests that this mutation
has arisen only once in the history of dog domestication.
Received: 12 January 2001 / Accepted: 1 April 2001 相似文献
70.