全文获取类型
收费全文 | 346篇 |
免费 | 20篇 |
国内免费 | 14篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 11篇 |
2017年 | 8篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 11篇 |
2013年 | 22篇 |
2012年 | 6篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 15篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 12篇 |
2005年 | 15篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有380条查询结果,搜索用时 86 毫秒
1.
Ethnobotanical review of wild edible plants in Spain 总被引:5,自引:0,他引:5
JAVIER TARDÍO MANUEL PARDO-DE-SANTAYANA RAMÓN MORALES 《Botanical journal of the Linnean Society. Linnean Society of London》2006,152(1):27-71
This paper compiles and evaluates the ethnobotanical data currently available on wild plants traditionally used for human consumption in Spain. Forty-six ethnobotanical and ethnographical sources from Spain were reviewed, together with some original unpublished field data from several Spanish provinces. A total of 419 plant species belonging to 67 families was recorded. A list of species, plant parts used, localization and method of consumption, and harvesting time is presented. Of the seven different food categories considered, green vegetables were the largest group, followed by plants used to prepare beverages, wild fruits, and plants used for seasoning, sweets, preservatives, and other uses. Important species according to the number of reports include: Foeniculum vulgare , Rorippa nasturtium-aquaticum , Origanum vulgare , Rubus ulmifolius , Silene vulgaris , Asparagus acutifolius , and Scolymus hispanicus . We studied data on the botanical families to which the plants in the different categories belonged, overlapping between groups and distribution of uses of the different species. Many wild food plants have also been used for medicinal purposes and some are considered to be poisonous. This review highlights the rich traditional knowledge on edible plants that has remained in rural Spain. Until recently, many wild plants were used as dietary supplements. However, most of this knowledge survives only in the memory of the elderly, and will probably disappear in a few decades. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 27–71. 相似文献
2.
S SPIEGEL D HOLLAND Y TAM I BAR-YAAKOV L MASLENIN A ROSNER 《The Annals of applied biology》2004,144(2):229-236
Prunus necrotic ringspot virus (PNRSV) was detected in almonds, plum and apricot germplasm accessions and local almond cultivars in Israel. PNRSV was widespread both in wild and cultivated almond trees and uncommon in wild apricots and plums. The possible variation among the PNRSV isolates was initially evaluated by restriction analysis of PCR products representing the CP gene with the endonuclease RsaI and followed by nucleotide sequence analysis of selected isolates. It was concluded that all 13 isolates belong to group PV96, the largest cluster of PNRSV isolates, described previously. Two PNRSV isolates, one from a plum accession and one from an almond cultivar, were found to be distinct members of group PV96 with unique nucleotide modifications not found in other documented isolates of this virus. However, no PNRSV isolate typical to a specific host and/or to the Middle East region could be identified. This study expands the body of data on variability of PNRSV isolates and highlights the importance of assessing the virus status of germplasm collections by applying reliable diagnostic and differentiating methods. 相似文献
3.
Summary The foraging behavior of the subterranean mole rat Spalax ehrenbergi (Rodentia, Spalacidae) was tested according to the framework of optimal foraging theory. We compared the frequencies of food species hoarded in storage chambers of mole rats with the frequencies of these species occurring in the vicinity of the mole rats' nest mounds during the winter and spring seasons. In addition, we examined the food composition of several summer nest mounds. Laboratory observations were conducted in order to test the foraging behavior of mole rats under simulated subterranean conditions. The mole rat is a generalist and collects a variety of food species. Out of 33 plant species that were hoarded by mole rats in the 21 studied nest mounds, 61% (n=20) were geophytes, 21% (n=7) perennial herbs, 15% (n=5) annual herbs and 3% (n=1) dwarf shrubs. The frequency of each collected species in the 16 winter and spring nest mounds is in general accordance with its frequency in the mole rat's territory. This implies that the mole rat randomly samples the food reserve of its territory without special preference or directed search for a particular species. The collection or avoidance of any food item is not dependent on the presence or absence of any other food item. We suggest that the foragin generalism of the mole rat is a product of the constraints of a subterranean niche — the necessity to hoard food as much as possible in a limited time period and the high energetic investment of tunneling to the food items. 相似文献
4.
Summary Color notations of dorsal pelage were analyzed in 451 adult subterranean mole rats, comprising 19 populations and 4 chromosomal species (2n=52, 54, 58 and 60) of the Spalax ehrenbergi superspecies in Israel. In addition, the color notations of soil samples from the collection sites were measured. In an attempt to evaluate the degree of correlation between pelage color of mole rats and the local soil color, each color was compared both macro- and microgeographically. The macrogeographic comparisons were among populations of the 4 chromosomal species, and the microgeographic comparisons were among pairs of geographically neighboring subpopulations which occur under similar climatic conditions but differ in soil type and color. The results indicate that 1. no differences in pelage color notation exist between the sexes; 2. pelage of mole rats is generally characterized by an over-all grayish color, but its shades vary regionally and locally in accordance with varying soil color; 3. a positive correlation was found between pelage and local soil colors in the macrogeographic analysis and this correlation was verified in a microgeographic comparison; 4. specimens from populations of the northern chromosomal species (2n=52, 54) mainly inhabit terra rossa and basalt soils, respectively, with reddish brown tones, and they tend to have a more reddish shade, whereas animals from the central species (2n=58), which inhabits mainly dark soils including alluvial clays, terra rossa and brown rendzina and the souther species 2n=60, which occurs mainly in light soil types such as pale rendzina, sandy loams and loess, tend to have a more yellowish shade. The general appearance of specimens from 2n=58 was dark gray while that of 2n=60 specimens was light gray; 5. mole rats living in xeric environments (particularly 2n=60, but also 2n=54) are lighter than those which live in mesic environments (2n=52, 58). The results support the conclusion that pelage color of strictly subterranean mole rats is subject to selection pressures of overground predation of disharmonious types with their background soil color. The possibility that the pelage color variation and patterns also contributes to better thermoregulation while mole rats are above ground is discussed. 相似文献
5.
Summary Plant survival rate, root disease index and fresh shoot weight of subterranean clover seedlings inoculated with fungal pathogens
(Fusarium avenaceum, F. oxysporum, Phoma medicaginis, Pythium irregulare andRhizoctonia solani, both singly and in combinations) were generally inter-correlated over a wide range of temperature (10, 15, 20 and 25°C)
and moisture conditions (45, 65% water holding capacity and flooding). There was a negative correlation between root disease
index and shoot weight for all treatments exceptF. avenaceum + P. irregulare. Root disease index and seedling survival rate were negatively correlated except forF. oxygsporum, Phoma medicaginis, P. irregulare andF. oxysporum + F. avenaceum. However, a good positive correlation was found between the survival rate and shoot weight for all treatments with the exception
ofPhoma medicaginis. 相似文献
6.
Two new compounds isolated from the fruits of Pedalium murex are characterized as heptatriacontan-4-one and tetratriacontanyl octacosanoate by spectral studies. Pentatriacontane, sitosterol, hexatriacontanoic acid, hentriacontanoic acid, ursolic acid and vanillin have also been isolated and identified. 相似文献
7.
Ravindar Kaur-Sawhney Philip B. Applewhite Arthur W. Galston 《Plant Growth Regulation》1996,18(3):191-199
Thin longitudinal sections cut from pedicels of fifteen cultivars of tomato (Lycopersicon esculentum) were grown in vitro on Murashige-Skoog medium supplemented with various concentrations of different auxins and cytokinins. Isatin (an auxin precursor slowly converted to an active auxin) was the most effective source of auxin for the formation of buds without prior root formation, while zeatin was the most effective cytokinin for growth and development of the buds. Flower buds and ripe fruits developed consistently from explants of the cultivar Pixie Hybrid II treated with 10 M isatin plus 3 M zeatin as the cytokinin. Fruits developed parthenocarpically, grew to a diameter of about 15 mm, ripened promptly, and possessed normal color and flavor.Abbreviations BAP
benzylaminopurine
- IAA
indole-3-acetic acid
- IBA
indole-3-butyric acid
- IPA
isopentyladenosine
- NAA
-napthaleneacetic acid 相似文献
8.
9.
10.
Taposhi Hazra Sampa Kundu Subir Bera Tapan Chakraborty Mahasin Ali Khan 《植物分类学报:英文版》2023,61(6):1079-1090
The Ventilago Gaertn. (Rhamnaceae) is widely distributed in pantropical areas of Africa, Asia, and Australia. However, fossil records of this taxon are sparse, which limits understanding of the evolution and biogeographic history of the genus. In the present study, we report and describe two new fossil species of Ventilago, V. siwalika sp. nov. from the Miocene sediments of Himachal Pradesh, western Himalaya, and V. pliocenica sp. nov. from the Pliocene sediments of Jharkhand, eastern India based on single-winged samaras. Ventilago pliocenica is characterized by a prominent midvein, obtuse to sub-round apex with mucronate tip, longitudinal secondary veins extending the full length of the fruit, and reticulate nature of higher-order veins, the presence of equatorial rim, the hypanthium, and short pedicel. On the other hand, V. siwalika is characterized by a prominent midvein, obtuse to sub-round apex with mucronate tip, longitudinal secondary veins extending the full length of the fruit, and reticulate nature of higher-order veins. Our discovery represents the first unambiguous fossil record of single-winged samara of Ventilago from India and provides valuable insights into the evolution of this genus. In this paper, we also review its biogeographic history and add new information to understand its hypothetical migration route. Present and earlier records of Ventilago also suggest that this genus was a common forest element during Neogene (Miocene time) in Asia. 相似文献