全文获取类型
收费全文 | 376篇 |
免费 | 54篇 |
出版年
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 15篇 |
2010年 | 5篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 21篇 |
2001年 | 4篇 |
2000年 | 15篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1980年 | 11篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 8篇 |
1972年 | 6篇 |
1971年 | 9篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1964年 | 4篇 |
1959年 | 4篇 |
1958年 | 3篇 |
1951年 | 3篇 |
1943年 | 5篇 |
1941年 | 3篇 |
1940年 | 3篇 |
1931年 | 3篇 |
排序方式: 共有430条查询结果,搜索用时 718 毫秒
101.
Francis G. Howarth Shelley A. James Wendy McDowell David J. Preston Clyde T. Imada 《Journal of Insect Conservation》2007,11(3):251-261
Lava tube cave ecosystems on the volcanic islands of Hawai‘i support communities of rare and highly specialized cave arthropods.
In these cave ecosystems, plant roots, both living and dead, provide the main energy source for cave animals. Loss of deep-rooted
plants over caves will affect populations of cave-adapted animals living below. Furthermore, the loss of native plant species
will likely eliminate host specific cave animals. Thus, identification of plant roots currently found in caves is necessary
for the development of effective management actions that encourage the growth of appropriate deep-rooted plant species, thereby
protecting the underlying cave ecosystem. We used molecular techniques to identify plant roots found within cave ecosystems
on the islands of Maui and Hawai‘i. Sequences of the internal transcribed spacer (ITS) regions and the 5.8S gene of nuclear
ribosomal DNA from cave roots were compared to sequences of known plant species either collected on the surface over the footprint
of each cave or to sequences accessioned in GenBank. Roots in the cave ecosystem studied on Maui belonged to two alien tree
species: Eucalyptus tereticornis and Grevillea robusta. Within the Hawai‘i cave ecosystem, roots of two plant species were identified: the alien tree G. robusta and the native vine Cocculus orbiculatus. The Maui cave ecosystem supports populations of at least 28 species of arthropods, including eight that are blind obligate
cave inhabitants. The Hawai‘i cave ecosystem supports 18 arthropod species, of which three are cave-adapted. Creating protected
reserves around biologically significant caves, controlling, and preventing the introduction of harmful invasive plant species
within the cave footprint, and encouraging the establishment of deep-rooted native plant species is essential for the continued
survival of the unique ecosystems found within Hawaiian lava tube cave systems. 相似文献
102.
Pía Villanueva Ron Nudel Alexander Hoischen María Angélica Fernández Nuala H. Simpson Christian Gilissen Rose H. Reader Lillian Jara María Magdalena Echeverry Clyde Francks Gillian Baird Gina Conti-Ramsden Anne O’Hare Patrick F. Bolton Elizabeth R. Hennessy SLI Consortium Hernán Palomino Luis Carvajal-Carmona Joris A. Veltman Jean-Baptiste Cazier Zulema De Barbieri Simon E. Fisher Dianne F. Newbury 《PLoS genetics》2015,11(6)
103.
104.
Clark LB Viswanathan P Quigley G Chiang YC McMahon JS Yao G Chen J Nelsbach A Denis CL 《The Journal of biological chemistry》2004,279(14):13616-13623
CCR4, a poly(A) deadenylase of the exonuclease III family, is a component of the multiprotein CCR4-NOT complex of Saccharomyces cerevisiae that is involved in mRNA degradation. CCR4, unlike all other exonuclease III family members, contains a leucine-rich repeat (LRR) motif through which it makes contact to CAF1 and other factors. The LRR residues important in contacting CAF1 were identified by constructing 29 CCR4 mutations encompassing a majority (47 of 81) of residues interstitial to the conserved structural residues. Two-hybrid and immunoprecipitation data revealed that physical contact between CAF1 and the LRR is blocked by mutation of just two alpha-helix/beta-helix strand loop residues linking the first and second repeats. In contrast, CAF16, a potential ligand of CCR4, was abrogated in its binding to the LRR by mutations in the N terminus of the second beta-strand. The LRR domain was also found to contact the deadenylase domain of CCR4, and deletion of the LRR region completely inhibited CCR4 enzymatic activity. Mutations throughout the beta-sheet surface of the LRR, including those that did not specifically interfere with contacts to CAF1 or CAF16, significantly reduced CCR4 deadenylase activity. These results indicate that the CCR4-LRR, in addition to binding to CAF1, plays an essential role in the CCR4 deadenylation of mRNA. 相似文献
105.
Smoot EC 《Plastic and reconstructive surgery》2003,112(1):340-341
106.
A genomewide scan for attention-deficit/hyperactivity disorder in an extended sample: suggestive linkage on 17p11 总被引:11,自引:0,他引:11
下载免费PDF全文
![点击此处可从《American journal of human genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ogdie MN Macphie IL Minassian SL Yang M Fisher SE Francks C Cantor RM McCracken JT McGough JJ Nelson SF Monaco AP Smalley SL 《American journal of human genetics》2003,72(5):1268-1279
Attention-deficit/hyperactivity disorder (ADHD [MIM 143465]) is a common, highly heritable neurobehavioral disorder of childhood onset, characterized by hyperactivity, impulsivity, and/or inattention. As part of an ongoing study of the genetic etiology of ADHD, we have performed a genomewide linkage scan in 204 nuclear families comprising 853 individuals and 270 affected sibling pairs (ASPs). Previously, we reported genomewide linkage analysis of a "first wave" of these families composed of 126 ASPs. A follow-up investigation of one region on 16p yielded significant linkage in an extended sample. The current study extends the original sample of 126 ASPs to 270 ASPs and provides linkage analyses of the entire sample, using polymorphic microsatellite markers that define an approximately 10-cM map across the genome. Maximum LOD score (MLS) analysis identified suggestive linkage for 17p11 (MLS=2.98) and four nominal regions with MLS values >1.0, including 5p13, 6q14, 11q25, and 20q13. These data, taken together with the fine mapping on 16p13, suggest two regions as highly likely to harbor risk genes for ADHD: 16p13 and 17p11. Interestingly, both regions, as well as 5p13, have been highlighted in genomewide scans for autism. 相似文献
107.
A genomewide scan for loci involved in attention-deficit/hyperactivity disorder 总被引:10,自引:0,他引:10
下载免费PDF全文
![点击此处可从《American journal of human genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fisher SE Francks C McCracken JT McGough JJ Marlow AJ MacPhie IL Newbury DF Crawford LR Palmer CG Woodward JA Del'Homme M Cantwell DP Nelson SF Monaco AP Smalley SL 《American journal of human genetics》2002,70(5):1183-1196
Attention deficit/hyperactivity disorder (ADHD) is a common heritable disorder with a childhood onset. Molecular genetic studies of ADHD have previously focused on examining the roles of specific candidate genes, primarily those involved in dopaminergic pathways. We have performed the first systematic genomewide linkage scan for loci influencing ADHD in 126 affected sib pairs, using a approximately 10-cM grid of microsatellite markers. Allele-sharing linkage methods enabled us to exclude any loci with a lambda(s) of > or =3 from 96% of the genome and those with a lambda(s) of > or =2.5 from 91%, indicating that there is unlikely to be a major gene involved in ADHD susceptibility in our sample. Under a strict diagnostic scheme we could exclude all screened regions of the X chromosome for a locus-specific lambda(s) of >/=2 in brother-brother pairs, demonstrating that the excess of affected males with ADHD is probably not attributable to a major X-linked effect. Qualitative trait maximum LOD score analyses pointed to a number of chromosomal sites that may contain genetic risk factors of moderate effect. None exceeded genomewide significance thresholds, but LOD scores were >1.5 for regions on 5p12, 10q26, 12q23, and 16p13. Quantitative-trait analysis of ADHD symptom counts implicated a region on 12p13 (maximum LOD 2.6) that also yielded a LOD >1 when qualitative methods were used. A survey of regions containing 36 genes that have been proposed as candidates for ADHD indicated that 29 of these genes, including DRD4 and DAT1, could be excluded for a lambda(s) of 2. Only three of the candidates-DRD5, 5HTT, and CALCYON-coincided with sites of positive linkage identified by our screen. Two of the regions highlighted in the present study, 2q24 and 16p13, coincided with the top linkage peaks reported by a recent genome-scan study of autistic sib pairs. 相似文献
108.
109.
110.