首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   376篇
  免费   26篇
  国内免费   3篇
  2022年   2篇
  2020年   2篇
  2017年   6篇
  2016年   8篇
  2015年   13篇
  2014年   15篇
  2013年   12篇
  2012年   14篇
  2011年   14篇
  2010年   21篇
  2009年   20篇
  2008年   22篇
  2007年   24篇
  2006年   7篇
  2005年   11篇
  2004年   16篇
  2003年   11篇
  2002年   16篇
  2001年   10篇
  2000年   14篇
  1999年   7篇
  1998年   12篇
  1997年   8篇
  1996年   7篇
  1995年   4篇
  1994年   3篇
  1993年   5篇
  1992年   8篇
  1991年   9篇
  1990年   8篇
  1989年   6篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   5篇
  1984年   3篇
  1983年   2篇
  1982年   3篇
  1981年   4篇
  1979年   2篇
  1978年   5篇
  1977年   2篇
  1975年   3篇
  1974年   5篇
  1973年   6篇
  1972年   2篇
  1971年   5篇
  1970年   2篇
  1969年   3篇
  1965年   2篇
排序方式: 共有405条查询结果,搜索用时 15 毫秒
11.
Abstract

Post-construction avifauna investigations were undertaken at Project West Wind, Meridian Energy Limited's 62-turbine wind farm on the Wellington south coast. These investigations were required in accordance with the resource consent conditions to quantify the level of avian mortalities occurring at the wind farm, particularly in regard to New Zealand falcon (Falco novaeseelandiae), kākā (Nestor meridionalis) and kererū (Hemiphaga novaeseelandiae). This is the first comprehensive study at a New Zealand operating wind farm. The methods included three field components necessary to calculate annual estimates of mortalities across the wind farm site: routine turbine searches; carcass detection trials; and carcass removal trials. Results from years 1 and 2 of a three-year programme are presented. To date, mortalities have been recorded for 17 taxa at 18 of the 24 study turbines. There have been no recorded mortalities of falcon, kākā or kererū. Australasian harrier (Circus approximans) has been the species for which the most mortalities have been recorded. Overall estimated annual mortality rates for years 1 and 2 were calculated to be approximately six and five birds per turbine respectively.  相似文献   
12.
The transmembrane protein nephrin is a key component of the kidney slit diaphragm that contributes to the morphology of podocyte foot processes through signaling to the underlying actin cytoskeleton. We have recently reported that tyrosine phosphorylation of the cytoplasmic tail of nephrin facilitates recruitment of Nck SH2/SH3 adaptor proteins and subsequent actin remodeling and that phosphorylation of the Nck binding sites on nephrin is decreased during podocyte injury. We now demonstrate that Nck directly modulates nephrin phosphorylation through formation of a signaling complex with the Src family kinase Fyn. The ability of Nck to enhance nephrin phosphorylation is compromised in the presence of a Src family kinase inhibitor and when the SH3 domains of Nck are mutated. Furthermore, induced loss of Nck expression in podocytes in vivo is associated with a rapid reduction in nephrin tyrosine phosphorylation. Our results suggest that Nck may facilitate dynamic signaling events at the slit diaphragm by promoting Fyn-dependent phosphorylation of nephrin, which may be important in the regulation of foot process morphology and response to podocyte injury.  相似文献   
13.
A LS Houde  C C Wilson  B D Neff 《Heredity》2013,111(6):513-519
The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non-additive genetic and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non-additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss whether the similarities in architectures of these populations is the result of natural selection across a common juvenile environment.  相似文献   
14.
We provide guidance for monitoring whether human activities affect the physiology or behavior of marine mammals and, if so, whether those effects may lead to changes in survival and reproduction at the population level. We suggest that four elements be included in designing and implementing such a monitoring program. The first is development of a theory of change: a set of mechanistic hypotheses that outline why a given activity might be expected to have one or more measurable effects on individuals and populations, and ideally the magnitude, timing, and duration of the effects. The second element, definition of biologically meaningful effect sizes, ultimately facilitates the development of a monitoring program that can detect those magnitudes of effect with the desired levels of precision. The third element, selection of response variables for monitoring, allows inference to whether observed changes in the status of individuals or populations are attributable to a given activity. Visual observations, passive acoustic and tagging instruments, and direct physical measurements all can provide data that facilitate quantitative hypothesis testing. The fourth element is specification of the temporal sequence of monitoring. These elements also can be used to inform monitoring of the responses of other taxonomic groups to human activities.  相似文献   
15.
16.
Cells harvested from Fanconi anemia (FA) patients show an increased hypersensitivity to the multifunctional DNA damaging agent mitomycin C (MMC), which causes cross-links in DNA as well as 7,8-dihydro-8-oxoguanine (8-oxoG) adducts indicative of escalated oxidative DNA damage. We show here that the Drosophila multifunctional S3 cDNA, which encodes an N-glycosylase/apurinic/apyrimidinic (AP) lyase activity was found to correct the FA Group A (FA(A)) and FA Group C (FA(C)) sensitivity to MMC and hydrogen peroxide (H2O2). Furthermore, the Drosophila S3 cDNA was shown to protect AP endonuclease deficient E. coli cells against H(2)O(2) and MMC, and also protect 8-oxoG repair deficient mutM E. coli strains against MMC and H2O2 cell toxicity. Conversely, the human S3 protein failed to complement the AP endonuclease deficient E. coli strain, most likely because it lacks N-glycosylase activity for the repair of oxidatively-damaged DNA bases. Although the human S3 gene is clearly not the genetic alteration in FA cells, our results suggest that oxidative DNA damage is intimately involved in the overall FA phenotype, and the cytotoxic effect of selective DNA damaging agents in FA cells can be overcome by trans-complementation with specific DNA repair cDNAs. Based on these findings, we would predict other oxidative repair proteins, or oxidative scavengers, could serve as protective agents against the oxidative DNA damage that occurs in FA.  相似文献   
17.
In personal interviews, people surrendering their dogs and cats to 12animal shelters in 4 regions of the country discussed their reasons for relinquishing their companion animals and answered questions about their own characteristics and those of their pet. The interviews identified 71 reasons for relinquishment. Personal issues lead the class of reasons for relinquishment of cats and ranked 3rd among those given for relinquishment of dogs. The top 3 health and personal issues cited for giving up cats were allergies of a family member to cats, owner's personal problems, and anew baby. For dogs, the top 3 reasons cited were lack of time for the dog, owner's personal problems, and allergies. Analysis of these health and personal issues suggests that education and counseling before and after acquisition of a pet, as well as the availability of temporary accommodations for pets during times of personal crisis, may reduce relinquishments.  相似文献   
18.
Temperate regions of Australia have extensive commercial plantations of Monterey pine, Pinus radiata D. Don. Replacement of indigenous forests by P. radiata is likely to have significant effects on assemblages of native Lepidoptera, and has been considered a major threat to native fauna through displacing native species. However, many species of Lepidoptera, including ennomine geometrid moths in the genus Chlenias Guenèe, have adopted P. radiata as a larval host. Comparisons were made of oviposition preferences and nutritional ecology of Chlenias auctaria Guenée on P. radiata and two native host plants [Acacia mearnsii De Wild. (Mimosaceae) and Eucalyptus obliqua LHérit (Myrtaceae)]. Females showed no significant oviposition preference for any of the three hosts. Growth of sixth instar larvae was significantly less on P. radiata than on the native hosts. Pupal weights were significantly lower, suggesting that the fitness of moths reared on P. radiata will be significantly reduced. The life history strategy of C. auctaria, which includes dispersal of first instar larvae by ballooning, may predispose this species to feed on poor quality hosts, and this may be common to other polyphagous species found feeding on P. radiata in southern hemisphere plantations. The impact of P. radiata may have a long term effect on lepidopteran communities, beyond the simple replacement of indigenous host plants leading to extirpations of feeding specialists.  相似文献   
19.
20.
A 14-year-old Native American girl from the Iroquois Nation was referred as a potential patient with the syndrome of Apparent Mineralocorticoid Excess. Instead, her evaluation revealed resistance to glucocorticoids, mineralocorticoids, and androgens. She lacked Cushingoid features in spite of significantly high cortisol levels. Menstruation was regular and there was no clinical evidence of masculinization despite high serum androgen levels in the male range. The patient's sister had similar clinical features. Partial resistance to exogenous glucocorticoid and mineralocorticoid administration was well demonstrated in both patients. It is proposed that these patients represent the first cases of partial resistance to multiple steroids, possibly owing to a coactivator defect.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号