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排序方式: 共有337条查询结果,搜索用时 78 毫秒
61.
I. Bruni F. De Mattia S. Fluch C. Ferrari M. Corazza E. Dinelli 《Plant biosystems》2016,150(3):449-458
Hybridization between Rhododendron ferrugineum L. and R. hirsutum L. in south-eastern Alps was examined in order to (i) evaluate the breeding direction and the extent of backcrossing between hybrids and the parental species, (ii) define which processes facilitate speciation and maintain species identities and (iii) clarify the role of rock geochemistry in hybridization events. Individuals of three hybrid populations were analysed by morphological and molecular markers. The internal transcribed spacer and trnH–psbA distinguished the parental species and F1 hybrids while only the simple sequence repeat markers recognized genotype classes: F, H, F1, F2, BxF (backcross to R. ferrugineum) and BxH (backcross to R. hirsutum). Combining morphological and molecular data, we found that the tested populations had complex genetic structure: the F1 individuals produce F2 hybrids and backcross to parental species. Due to R. hirsutum phenology, most backcrossing events were with this parental species (asymmetric hybridization). Geochemical analyses indicate that alkaline soil conditions linked to calcareous dolomitic rocks promoted the genetic assimilation of R. hirsutum. In addition, R. x intermedium shows a higher edaphic adaptation than R. hirsutum as it can be found on a wide range of calcareous-dolomitic rocks as well as on weakly acidic soils of natural or anthropogenic origin. 相似文献
62.
基于9个20 m×30 m森林群落样地的调查数据,采用物种丰富度、α和β多样性指数,对辽东山地古石河冰缘地貌不同林型石生、树生苔藓植物物种多样性进行定量研究,采用皮尔逊相关分析方法对其影响因素进行分析。结果显示,古石河冰缘地貌苔藓植物共有26科46属59种;不同林型石生、树生苔藓植物物种丰富度和α多样性指数均为:暗针叶林针阔混交林落叶阔叶林;石生苔藓植物β多样性指数最高为落叶阔叶林-针阔混交林间(0.44),最低为落叶阔叶林-暗针叶林间(0.33);树生苔藓植物β多样性指数最高为针阔混交林-暗针叶林间(0.40),最低为落叶阔叶林-暗针叶林间(0.25);分析表明,林冠层郁闭度、海拔高度是影响辽东山地古石河冰缘地貌森林生态系统苔藓物种多样性的重要因子。 相似文献
63.
A study was undertaken to isolate some fungi exhibiting phosphate-dissolution ability, and to test whether these fungi are
capable of increasing the amount of available P in a calcareous soil treated with rock phosphate (RP) or with triple superphosphate
(TSP) and its subsequent uptake by sorghum (Sorghum bicolor L. Moench).Penicillium sp. and twoAspergillus foetidus (Naka) isolates significantly increased the availability of P in soil treated with RP or TSP during the growing season.Penicillium sp. isolate was more effective in increasing available P in the soil treated with RP or TSP than were Aspergillus isolates.
However, the dry matter and P uptake responses to inoculation with these fungi were better in the soil treated with RP than
in soil treated with TSP. In the TSP treated soil, the fungi achieved their maximum P releasing capacity two weeks earlier
than in soil treated with RP. Positive and significant correlation coefficients among available P, P uptake and dry matter
production at different periods of the growing season were observed following inoculation. However, none of these variables
were found to be significantly correlated with the fungal populations. 相似文献
64.
K. M. Evans P. Y. Ladiges E. Newbigin P. K. Ades 《Plant Systematics and Evolution》2001,227(1-2):105-115
Banksia saxicola A.S. George (Proteaceae) is a rare Australian endemic, found in only two locations in Victoria that are separated by approximately
500 kms: the Grampians and Wilson's Promontory National Parks. The organisation of genetic variation between and within populations
at the two locations was assessed using the Amplified Fragment Length Polymorphism (AFLP) technique. Two populations were
sampled in the Grampians National Park and one population was sampled at Wilson's Promontory. The three populations were genetically
divergent from each other, in particular the Grampians and Wilson's Promontory populations, and this relates to the ancient
geographic isolation of these two regions. The Wilson's Promontory population had lower genetic diversity than either Grampians
populations, consistent with its smaller population size. The findings are important for strategies to conserve B. saxicola.
Received October 3, 2000 Accepted January 3, 2001 相似文献
65.
66.
Nine novel microsatellite loci were isolated from Oplegnathus fasciatus by screening an enriched genomic library using nonradioactive PCR (polymerase chain reaction) techniques. All loci were found to be polymorphic with an average of 8.1 alleles per locus (range 3–15). The mean observed and expected heterozygosities were 0.71 (range 0.40–1.00) and 0.74 (range 0.50–0.90), respectively. Two loci showed significant Hardy–Weinberg disequilibrium at the P < 0.05 level. The high variabilities revealed in this study suggest that these microsatellite loci should provide useful markers for genetic variation monitoring of O. fasciatus. 相似文献
67.
68.
《L'Anthropologie》2019,123(1):66-99
In the North of the plain drained by Calavon and at the foot of the mounts of Vaucluse, the cliff of Baume Brune is long about 900 m. We count 43 natural shelters of which only 10 are marked by painted figures belonging to the schematic iconography of the Neolithic period. The painted shelters are chosen, according among others, to four criteria, which are their dominant visual position, their southern exposure, the “red” tint of their walls and their episodic humidity. While a selection of these criteria might be present in the non-decorated shelters of Baume Brune, all of them are always found in the painted shelters. Yet, sometimes their presence if not so obvious, as there are shelters once painted in red tint whose walls are now covered by small carbonate flowstones formed by the flow of water after centuries of rain events. We also propose that iconography was perceived as a factor contributing to the placement of rock art, for single shelters were chosen by prehistoric artists to paint schematic key themes (male figures, idols, quadrupeds). Finally, we investigate the acoustic dimension of Baume Brune by comparing the distant and close auditory perception of painted and non-painted shelters. In this framework, we argue that shelters with rock art possess the greatest acoustic qualities of the whole cliff. 相似文献
69.
Judy Tasse 《Zoo biology》1986,5(1):27-43
The maternal and paternal behavior of Kerodon rupestris was examined. Quantitative differences between fathers and mothers and between mothers raising young with fathers present and with fathers absent were assessed. Growth rates of young raised by paired females and by lone females were compared. The male provides direct paternal care to the young by engaging in allogrooming, sniffing, and huddling. There is no significant difference between the sexes in the amount of contact promoting behavior given to the offspring, nor are the sexes significantly different in the amount of exploratory sniffing of the offspring. When the male is absent, the female spends a greater amount of time in contact with the young. Young raised by lone females gained significantly more weight than young raised by paired females. The suggestion that indirect paternal care acts to reduce female aggression to the young and relieve the energy expenditure burden of the female is discussed. The results indicate that social experience is gained at the expense of physical nurturing when the male is present. 相似文献
70.
裂隙发育的喀斯特出露基岩生境,虽无土层覆盖却能维持不同生活型植物的水分消耗.然而目前对该类生境植物的水分来源缺乏清晰认识.本研究以植物潜在水分来源相对简单的孤立出露基岩为例,聚焦遮雨(即剔除雨水对浅层水源的补给)1年后仍然生长旺盛的代表性植物种,同时以无遮雨处理样地(即始终接受降雨补给)的同种植物为对照,运用稳定性氢氧同位素技术,结合对植物水势的测定,综合分析了3种典型植物(落叶乔木菜豆树、落叶乔木紫弹树、常绿灌木四子海桐)的水分来源.结果表明: 在降水充沛的雨季,遮雨条件下3种植物均依赖与泉水同位素比率相近的深层水源,这是植物在遮雨1年后仍能正常生长的根本原因;遮雨菜豆树和四子海桐凌晨水势与自然植株无显著差异,表明植物未受水分胁迫,而紫弹树凌晨水势显著低于自然植株,表明其受一定程度的水分胁迫;自然条件下,3种植物茎水同位素比率均显著低于遮雨植株,且处于近期雨水同位素比率波动范围内,表明植物均依赖受近期雨水主导的浅层水源.遮雨和自然条件下,四子海桐正午水势与凌晨水势始终无明显差异,表现出较为保守的水分利用策略;另外2种植物正午水势显著低于凌晨水势,属于偏挥霍型水分利用策略.具备利用浅层和深层水源的能力是喀斯特无土覆盖出露基岩生境植物适应不同水分环境和维持多样化水分利用策略的关键. 相似文献