全文获取类型
收费全文 | 375篇 |
免费 | 22篇 |
国内免费 | 7篇 |
专业分类
林业 | 39篇 |
农学 | 36篇 |
基础科学 | 7篇 |
65篇 | |
综合类 | 70篇 |
农作物 | 10篇 |
水产渔业 | 15篇 |
畜牧兽医 | 128篇 |
园艺 | 12篇 |
植物保护 | 22篇 |
出版年
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 27篇 |
2012年 | 28篇 |
2011年 | 33篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 11篇 |
2007年 | 24篇 |
2006年 | 20篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有404条查询结果,搜索用时 31 毫秒
1.
Genetic diversity estimates in Cicer using AFLP analysis 总被引:2,自引:0,他引:2
Amplified fragment length polymorphism (AFLP) analysis was used to evaluate the genetic variation among cultivated chickpea and wild Cicer relatives. In total, 214 marker loci were assessed, of which 211 were polymorphic (98.6%) across the 95 accessions that represented 17 species of Cicer. The genetic variation within a species was highest in C. pinnatifidum followed by C. reticulatum and lowest in C. macracanthum. Three main species groups were identified by UPGMA clustering using Nei's pair‐wise distance calculations. Group I included the cultivated species C. arietinum, C. reticulatum and C. echinospermum. Within this group, C. reticulatum accessions were clustered closest to the C. arietinum cultivars ‘Lasseter’, ‘Kaniva’ and ‘Bumper’, supporting the hypothesis that C. reticulatum is the most probable progenitor of the cultivated species. Cicer bijugum, C. judaicum and C. pinnatifidum were clustered together creating group II. Group III contained all nine perennial species assessed and two annual species C. yamashitae and C. cuneatum. The genetic distance detected between group I and group III (0.13) was equivalent to the genetic distance detected between group I and group II (the primary and annual tertiary species, respectively; 0.14). This indicated that the perennial tertiary species may be as valuable for increasing variation to incorporate novel germplasm in the cultigen as the annual tertiary species. 相似文献
2.
Emin Zeki Başkent Ali İhsan Kadıoğulları 《Scandinavian Journal of Forest Research》2014,29(7):121-131
Decision support systems (DSSs) are indispensable tools in preparing a forest management plan for a better combination of multiple forest values. This study attempted to develop and explain a stand-based forest management DSS (Ecosystem-based multiple-use forest planning [ETÇAP]) comprising a traditional simulation, linear programming (LP), metaheuristics and geographic information system. The model consists of five submodels; traditional management approach to handle inventory data, an empirical growth and yield model, a simulation to conceptualize management actions, a LP technique to optimize resource allocation and a simulated annealing approach to directly create a spatially feasible harvest schedule. The ETÇAP model has been implemented in a comparative two case study areas; Denizli–Honaz and Akseki–Ibrad?. Both simulation and optimization models outperformed to the traditional management plan. The periodical change of growing stock, allowable cuts, carbon sequestration and water production are used as performance indicators. The results showed that more amount of wood could be harvested over time compared to traditional level of harvesting. It could be concluded that various management strategies allowed managers to stimulate more decision options for better outputs through intertemporal trade-offs of management interventions as the model provided tools to quantify forest dynamics over time and space. Challenges exist to establish the functional relationships between forest structure and values for better quantification and integration into the management plans. 相似文献
3.
Son Truong NGUYEN Masaharu MOTOKAWA Tatsuo OSHIDA Hideki ENDO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2016,78(2):187-198
Southeast Asia is a region of high biodiversity, containing species of plants and animals that are yet to be
discovered. In this region, bats of the subfamily Kerivoulinae are widespread and diverse with six species
recorded in Vietnam. However, the taxonomy of the Kerivoulinae in Asia is complicated. In our study, we used
diagnostic characters and multivariate analysis to determine morphological differences between the genera
Kerivoula and Phoniscus. We showed that the two genera are distinguishable
by the size of second upper incisors, the shape of skull, nasal sinus, canines, second upper and lower
premolars. In addition, the two genera can be osteometrically separated by measurements of the braincase
height, interorbital width and shape of anterior palatal emargination. Our data clearly revealed the
morphological variations in the skull shape of Kerivoula hardwickii in Vietnam. This suggests
a possible separation into three morphotypes, representing cryptic species supported by statistical
differences with wide variation in skull shape, size and teeth. These results demonstrated Kerivoula
hardwickii can be separated three subspecies, and the result will serve as the basis for the future
assessment and classification of this group in Southeast Asia. 相似文献
4.
5.
In the present study, the effects of cefquinome, a 4th generation cephalosporin, on clinical, biochemical, haematological, and blood gas variables were investigated. Five healthy dogs were injected with cefquinome (1 mg/kg body weight, IM, daily) for 14 days. Negative effects of cefquinome on clinical, biochemical, and haematological variables were not observed, but it did change some blood gas variables. 相似文献
6.
7.
中早熟甜椒新品种中椒11号的选育 总被引:1,自引:0,他引:1
Sweet pepper; Zhongjiao No.11; F1 hybrid.; 【摘要】 中椒11号为中早熟甜椒一代杂种。其母本91-126是利用国内甜、辣椒及国外的甜椒为材料,经杂交、回交、添加杂交和单株选择转育而成的抗病、优质甜椒高代自交系,父本92-2-3为早熟、结果率高、配合力强的甜椒高代自交系。中椒11号熟性中早,定植至采收40d(天)左右,产量3000~5000kg·(667m2)-1,抗逆性强,抗TMV、中抗CMV,耐湿热;适于华南南菜北运基地冬季种植或北方早春保护地及露地早熟栽培;果实长灯笼形,果色绿,肉厚,味甜,商品率高,耐贮运。已在广东、海南、山东、北京等地种植,推广面积达1500hm2。 相似文献
8.
9.
1. This study was conducted using male broiler chickens to determine the effects of ascorbic acid, aspirin, ascorbic acid+aspirin, vitamin E+selenium and ascorbic acid+aspirin+vitamin E+selenium supplementations on haematological parameters and serum superoxide dismutase concentration. 2. One hundred and twenty day-old male Hubbunt broiler chicks were randomly divided into 6 experimental groups of 20 chicks each and placed in different pens. Groups 2, 3, 4, 5 and 6 were given a diet supplemented with ascorbic acid, aspirin (in water), ascorbic acid+aspirin, vitamin E+selenium and ascorbic acid+aspirin+vitamin E+selenium, respectively for 45 d while group 1 was given a commercial broiler diet. 3. There was no significant effect of ascorbic acid, aspirin, ascorbic acid+aspirin, vitamin E+selenium supplementations on any of the haematological parameters (red blood cell, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin concentration, mean corpuscular haemoglobin) in broilers but ascorbic acid+aspirin+vitamin E+selenium supplementation significantly decreased the white blood cell counts. 4. In addition to this, ascorbic acid, aspirin, ascorbic acid+aspirin and ascorbic acid+aspirin+vitamin E+selenium supplementations had no significant effect on the serum superoxide dismutase level, but vitamin E+selenium supplementation increased the serum superoxide dismutase level. 相似文献
10.
随着社会的发展,人们的工作和生活节奏也日益加快。与此同时,工作压力和心理压力也不断增加,在这种情况下,如不注意科学健身和均衡饮食,将会导致人们向亚健康群体过渡。新的饮食习惯、逐渐改善的卫生条件、全球旅行、药品用量和逐步增加的精神压力等都在影响着我们的健康并导致肠胃内菌群失调。肠胃中不均衡的菌群有可能引发免疫力降低、肠胃功能紊乱等常见问题。而益生菌可以有效维护肠道菌群生态平衡,形成生物屏障,抑制有害菌对肠道的侵蚀,提高人体免疫功能,减少毒素在体内的蓄积,防止疾病发生。1益生菌及其功能人体肠道中存在着数十亿种… 相似文献