全文获取类型
收费全文 | 599篇 |
免费 | 62篇 |
国内免费 | 1篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 16篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 19篇 |
2017年 | 12篇 |
2016年 | 13篇 |
2015年 | 36篇 |
2014年 | 39篇 |
2013年 | 24篇 |
2012年 | 51篇 |
2011年 | 51篇 |
2010年 | 28篇 |
2009年 | 27篇 |
2008年 | 44篇 |
2007年 | 39篇 |
2006年 | 33篇 |
2005年 | 25篇 |
2004年 | 37篇 |
2003年 | 27篇 |
2002年 | 31篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 3篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有662条查询结果,搜索用时 15 毫秒
131.
N. J. Waltham J. Schaffer J. Buist M. Geyle D. Toby 《Wetlands Ecology and Management》2018,26(6):1143-1156
Importance of community stakeholder participation in coastal freshwater and tidal wetland monitoring and restoration has become increasingly recognised. In Australia, Land and Sea Rangers (LSR) are appointed land and sea custodians from local indigenous communities and under guidance of experts learn a range of scientifically relevant and rigorous sampling techniques to protect and conserve Country. Scientific training to build LSR confidence to tackle restoration and conservation of sensitive and culturally important wetlands is shown here. Between May 2014 and May 2015 three training campaigns were completed where LSR on Boigu and Saibai Islands (the most northern islands in the Torres Straits, Australia), completed water quality and wetland flora/fauna surveys across both islands. Forty wetland fauna species were documented (with a similar wetland assemblage on each ANOSIM P?>?0.4) comprising 35 fish species (including the invasive freshwater climbing perch, Anabas testudineus), two crustaceans, a freshwater turtle (Chelodina oblonga) (a relic freshwater species after the last sea level rise approximately 6,000 years ago in the region), and two mangrove snakes (Myron richardsoni and Fordonia leucobalia) (both snake records represent a range extension). This data was presented at community workshops with the purpose to build LSR confidence, and with the community, develop a plan to conserve wetland cultural and environmental values. Five thematic wetland conservation themes were identified which resulted in agreeing to management actions necessary on both islands. Since the inception of this program in 2014, additional LSR restoration and monitoring programs have extended to wetlands on other islands in the Torres Straits. We advocate the need for more remote area wetland monitoring and management programs facilitated through LSR programs. 相似文献
132.
Garabet G. Toby Tongyao Liu Yang Buyue Xin Zhang Alan J. Bitonti Glenn F. Pierce Jurg M. Sommer Haiyan Jiang Robert T. Peters 《PloS one》2016,11(2)
Introduction
Hemophilia B is an inherited X chromosome–linked disorder characterized by impaired blood clotting owing to the absence of functional coagulation factor IX. Due to the relatively short half-life of factor IX, patients with hemophilia B require frequent factor IX infusions to maintain prophylaxis. We have developed a recombinant factor IX (rFIX) fused to the Fc region of IgG (rFIXFc) with an extended half-life in animals and humans.Materials and Methods
Procoagulant properties of rFIXFc and rFIX (BENEFIX®) were compared to determine the effect of the Fc region on rFIXFc hemostatic function. Specifically, we assessed rFIXFc activation, intermolecular interactions within the Xase complex, inactivation by antithrombin III (AT) and thrombin generation potential compared with rFIX. We also assessed the acute and prophylactic efficacy profiles of rFIXFc and rFIX in vivo in hemophilia B mouse bleeding models.Results and Conclusions
The activation by factor XIa or factor VIIa/tissue factor, inhibition by AT, interaction profiles with phospholipids, affinities for factor VIIIa within the context of the Xase complex, and thrombin generation profiles were similar for rFIXFc and rFIX. Xase complexes formed with either molecule exhibited similar kinetic profiles for factor Xa generation. In acute efficacy models, mice infused with rFIXFc or rFIX were equally protected from bleeding. However, in prophylactic efficacy models, protection from bleeding was maintained approximately three times longer in rFIXFc-dosed mice than in those given rFIX; this prolonged efficacy correlates with the previously observed half-life extension. We conclude that rFIXFc retains critical FIX procoagulant attributes and that the extension in rFIXFc half-life translates into prolonged efficacy in hemophilia B mice. 相似文献133.
Fred H. Pruslin Elisabeth Imesch Ronald Winston Toby C. Rodman 《Molecular reproduction and development》1987,18(2):179-190
The basic nuclear proteins of a fraction of elongating spermatids from human tests and of a fraction of motile spermatozoa from the ejaculate, separated by ion-exchange chromatography, were compared. Analysis by acetic acid-urea polyacrylamide gel electrophoresis (PAGE) showed that, in both fractions, four proteins of lower mobility were coeluted with protamine 1 by 23% guanidinium chloride (GuCI) while protamine 2 alone was eluted by 50% GuCI. Treatment with alkaline phosphatase identified those four proteins as phosphorylated protamines, and cyanogen bromide (CNBr) treatment of the dephosphorylated protamines distinguished them as variants of protamine 2 and not of protamine 1. Thus far, phosphorylated forms of protamine 1 have not been detected in either spermatids or spermatozoa. Those observations indicate that protamine 2 functions in the cycle of phosphorylation-dephosphorylation, which is essential to the process of sperm chromatin condensation, while the role of protamine 1 in human spermiogenesis is not yet defined. The presence of phosphorylated protamine in motile, presumably mature spermatozoa appears to be characteristic of human sperm but not of the sperm of other mammals and is probably the basis for the heterogeneity of chromatin condensation frequently observed in human spermatozoa. 相似文献
134.
135.
As an introduction to the special issue “Vegetation of Circumboreal Coniferous Forests”, a brief history is provided of the development and present state of floristic vegetation surveys of the boreal and mountain coniferous forests of Europe, northern Asia and North America. The focus is on forests assigned to the phytosociological classVaccinio-Piceetea and closely related vegetation types. 相似文献
136.
137.
138.
Zhengdong D Zhang Adam Frankish Toby Hunt Jennifer Harrow Mark Gerstein 《Genome biology》2010,11(3):R26
Background
Unitary pseudogenes are a class of unprocessed pseudogenes without functioning counterparts in the genome. They constitute only a small fraction of annotated pseudogenes in the human genome. However, as they represent distinct functional losses over time, they shed light on the unique features of humans in primate evolution. 相似文献139.
Inconspicuous, secretive, or sparsely distributed species receive relatively little research attention, potentially leading to uncertainty about their status and lack of efforts to conserve them. Karoo dwarf tortoises (Chersobius boulengeri) are endemic to South Africa, spend most of the time in retreats at remote arid locations, and are seldom seen. We conducted a 3-year (2018–2020) mark-recapture study to investigate the size and structure of the only Karoo dwarf tortoise population currently known to exist. The population in the 16-ha core of our study site consisted primarily of adult males and females, at a density of 3.3 individuals/ha. Many individuals had severely worn shells and appeared old. Small individuals (straight carapace length <65 mm) represented just 8% of the population and were mostly recent hatchlings. Overall, tortoises had high estimated survival rates (0.77–0.95; lower 95% confidence limit for the smallest tortoises was 0.16), despite a 15-month drought. The lack of small individuals may reflect low levels of recruitment and population decline. Predation by corvids was an obvious threat to all size classes. We estimated that the local population across the 250-ha study area was 800–900 males and females, and recommend precautionary conservation measures focused on reducing human-subsidized avian predation. 相似文献
140.