全文获取类型
收费全文 | 140篇 |
免费 | 5篇 |
国内免费 | 6篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 13篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有151条查询结果,搜索用时 593 毫秒
91.
Anders Jarnemo 《European Journal of Wildlife Research》2008,54(2):327-333
Red deer Cervus elaphus is a highly appreciated and intensively managed game species throughout Europe. A common management objective is a sustainable
harvest of large trophies. In southern Sweden, management has mainly aimed at preserving the nominate subspecies C. elaphus elaphus. Seasonal migration of red deer males may, however, complicate both harvest management as well as conservation efforts. I
used individually identified male red deer in southern Sweden to observe distance travelled from rutting areas to areas used
by males in summer and winter. Adult males were identified by antler shape and photo-documented during rut. Photos from the
rut were compared to trophies of deer harvested or found dead, to found cast antlers and to stags photographed during summer.
From 1969 to 2007, a distance between rutting ground and summer/winter quarters was established for 96 identified stags. An
average distance of 14 km and a maximum distance of 47 km were recorded between rut and summer/winter observations. The seasonal
migration of males increases the risk of overexploitation of males with harvest in both rutting areas and wintering areas.
Harvest management and conservation efforts may fail if males seasonally migrate outside the management unit. The results
suggest that seasonal migration must be considered in harvest management and conservation and that there is a need for a regulation
of male harvest. Furthermore, the study stresses that the success in deer management of single hunting units, may be largely
dependent on the harvest policies in the near surroundings as well as in areas tenths of kilometres away, suggesting that
a successful management must rely on co-operation and co-ordination on a landscape scale. 相似文献
92.
了解母体林麝(Moschus berezovskii)产后及幼体林麝断奶前后的免疫力和应激水平变化特征,可为特殊时期母体及幼体林麝的有效保护与饲养管理提供理论依据。该研究于2010年4至9月,采集哺乳期母体和幼体林麝的粪便样品,通过酶联免疫法对粪便提取液中免疫球蛋白(IgG、IgM和sIgA)以及皮质醇含量进行测定。利用SPSS 22.0对不同阶段母体和幼体林麝粪便样品中的免疫球蛋白和皮质醇水平进行单因素方差分析(one way-ANOVA)及多重比较。母体林麝粪便中IgG、IgM和sIgA的含量测定结果表明,粪便中IgG与IgM含量在分娩后的初期阶段处于较高水平,随着时间推移含量逐渐减少并保持基本稳定,且IgG与IgM表现出类似的变化趋势;sIgA含量在分娩后持续上升,一直持续到第14周后基本保持稳定。幼体林麝粪便中IgG、IgM和sIgA含量测定结果表明,免疫球蛋白表现出明显的变化规律,IgG和IgM含量在断奶(第11周龄左右)后明显下降,sIgA含量在断奶后有所下降,但变化不显著;在第16周龄左右,IgG和IgM含量再次升高,并随着时间的推移趋于稳定,sIgA则无显著变化。母体林麝皮质醇的数据结果表明,其产后的6周内,皮质醇处于较高水平,在第11周左右(断奶期)皮质醇水平有小幅度的升高。幼体林麝皮质醇的数据显示,其在出生后的第11周龄左右(断奶期)皮质醇含量同样呈现出与母体林麝类似的升高趋势,表明断奶这一行为对母体以及幼体林麝均造成一定的生理压力。综上,母体林麝产后的6周内是管护工作的敏感期,幼体林麝成长的第9 ~ 15周龄是其存活关键期。 相似文献
93.
94.
Christian Pitra Steffen Rehbein Walburga Lutz 《European Journal of Wildlife Research》2005,51(4):237-241
To determine the geographical origin of the sika deer (Cervus nippon) naturalized in Germany and Austria, we sequenced the mitochondrial control region for 214 individuals. Adding these sequences to previously published data from native sika deer across its natural geographic range, the total comes to 245, extending what is already known about the geographical variation in this sequence in Cervus nippon. From these sequences, a neighbour-joining tree was constructed. This tree showed that the 49 different mitochondrial (mt)DNA types are grouped into three distinct phylogenetic clusters, which correspond to different geographic areas. Similarities between sequences of the naturalized sika deer and those described from native sika deer from both southern Honshu, Kyushu with associated islands, and northern Honshu suggest that the ancestors of the sika deer populations in Germany and Austria originated from the Japanese archipelago. In contrast, there is no evidence that female sika deer of Chinese, Taiwanese or north Vietnamese origin were involved in the ancestry of the present sika population in Germany and Austria. 相似文献
95.
96.
中国大陆梅花鹿mtDNA控制区序列变异及种群遗传结构分析 总被引:17,自引:0,他引:17
测定了37只中国大陆梅花鹿(Cervus nippon)不同种群mtDNA控制区5′端351 bp的序列,共发现23个变异位点,定义了5种单元型。分子变异分析表明,中国大陆梅花鹿出现了显著的种群分化(Φm=0.45,Fst=0.60,P<0.001),支持把分布于东北、华南和四川的梅花鹿种群归入各自独立的管理单元。中国大陆、日本南部和日本北部之间无共享单元型,且有25个鉴别位点。最小跨度网络图(Minimum spannlng network,MSN)和基于最大似然法和邻接法的系统发生分析均把单元型聚类为对应于中国大陆、日本南部和日本北部的三个单系,其中中国大陆和日本南部梅花鹿有相对较近的亲缘关系,支持日本梅花鹿的祖先通过至少两个大陆桥从亚洲迁移到日本的观点。 相似文献
97.
梅花鹿的繁殖性能及数量遗传的研究 总被引:1,自引:0,他引:1
鹿茸是珍贵的滋补药品,鹿肉是低脂高蛋白肉食品。如能提高鹿的繁殖力和体重,就能提高鹿茸和鹿肉的产量。本文是对东北梅花鹿(Cervus nippon hortulorum模式亚种)在四川的繁殖性能和数量遗传的研究。 相似文献
98.
Jack P. Hayes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(4):453-459
Summary I compared the maximal aerobic metabolic rates (
), field metabolic rates (FMR), aerobic reserves (
-FMR), and basal metabolic rates (BMR) of wild and recently captured deer mice from low (440 m) and high (3800 m) altitudes. To separate the effects of the thermal environment from other altitudinal effects, I examined mice from different altitudes, but similar thermal environments (i.e., summer mice from high altitude and winter mice from low altitude). When the thermal environment was similar,
, FMR, and aerobic reserve of low and high altitude mice did not differ, but BMR was significantly higher at high altitude. Thus, in the absence of thermal differences, altitude had only minor effects on the aerobic metabolism of wild or recently captured deer mice.At low altitude, there was significant seasonal variation in
, FMR, and aerobic reserve, but not BMR. BMR was correlated with
, but not with FMR. The significant positive correlation of BMR with
indicates a cost of high
, because higher BMR increases food requirements and energy use during periods of thermoneutral conditions.Abbreviations
BMR
basal metabolic rate
-
FMR
field metabolic rate
-
partial pressure of oxygen
-
T
a
ambient temperature
-
T
b
body temperature
-
T
e
operative temperature
-
maximal aerobic metabolic rate 相似文献
99.
Botanical and chemical compositions of the rumen contents of 58 Sika deer on Mt Goyo, northern Japan, collected from summer
of 1988 to spring of 1989, were analyzed.Sasa nipponica, a dwarf bamboo, was important in summer (35.0%) and winter (61.4%), but it decreased to 5.6% and was replaced by browse
leaves in fall, and to 28.0% and was replaced by dead leaves, twigs and bark of woody plants in winter. Crude protein was
20–25% lower in the washed fraction than in the gross fraction. It was highest (16.2%) in summer and lowest (8.6%) in winter.
High protein content in summer and fall foods was attributed to forb and browse leaves. Seasonal fluctuation in protein content
in the foods of these Sika deer was greater than red deer on Rhum, Scotland and smaller than wapiti in Yellowstone National
Park, Wyoming, USA. Climatically, winter severity of Mt Goyo is intermediate between the two localities, which seems to explain
the seasonal fluctuation of the protein level. Crude fiber wasca 33% in the ‘washed’ fraction, and did not change seasonally. 相似文献
100.
东北梅花鹿是东北虎豹国家公园主要的大型食草动物之一,是东北虎豹的主要猎物,对针阔混交林群落的维持有关键的作用,探究其遗传多样性及空间遗传格局对东北梅花鹿的保护以及国家公园生态系统的健康至关重要。在国家公园珲春保护区内,通过非损伤方法获得遗传样本,利用微卫星标记,研究该梅花鹿种群的空间遗传格局及其影响因素。结果表明:本研究区梅花鹿种群平均期望杂合度为0.721,遗传多样性较为丰富。有限的扩散能力常常导致种群在遗传距离上具有显著的空间自相关模式,本研究区梅花鹿种群在0-1km距离等级内在遗传距离上具有显著的空间自相关现象,据此可推测,该地区梅花鹿扩散距离为1km左右。STRUCTURE分析表明,珲春地区梅花鹿种群不存在明显的遗传分化。各种空间变量可以显著影响物种的遗传分化。本研究选取海拔、坡度、坡向、地表起伏率、人类干扰5个变量,研究其对梅花鹿种群遗传结构的影响,这5个变量多被认为与大中型哺乳动物扩散阻碍相关。依据5个变量建立了336个阻力模型,并进行偏曼特尔检验。其中,依据海拔、坡向、地表起伏率、人类干扰假设建立的246个阻力模型与遗传距离之间的关系并不显著,综合所有变量的15个生境适宜性模型阻力模型与遗传距离的关系也都不显著。在依据坡度假设建构的75个阻力模型中,只有1个模型与遗传距离有显著的正相关关系,该模型同时也是在控制空间自相关影响后,在所有模型中与遗传距离相关性最高的模型。根据该模型推测,最适宜梅花鹿扩散的坡度为10°,梅花鹿可能倾向于利用缓坡进行扩散。结果对东北虎豹国家公园梅花鹿种群的保护具有重要意义。 相似文献