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排序方式: 共有132条查询结果,搜索用时 15 毫秒
91.
Cadmium toxicity in Nostoc UAM208: protection by calcium 总被引:1,自引:0,他引:1
92.
AS Glen D Anderson CJ Veltman PM Garvey M Nichols 《New Zealand journal of zoology.》2016,43(2):127-137
A major challenge in controlling overabundant wildlife is monitoring their populations, particularly as they decline to very low density. Camera traps and wildlife detector dogs are increasingly being used for this purpose. We compared the cost-effectiveness of these two approaches for detecting feral cats (Felis catus) on two pastoral properties in Hawke's Bay, North Island, New Zealand. One property was subject to intensive pest removal, while the other had no recent history of pest control. Camera traps and wildlife detector dogs detected cats at similar rates at both sites. The operating costs of each method were also comparable. We identify a number of advantages and disadvantages of each technique, and suggest priorities for further research. 相似文献
93.
Forage shrub production in the Mediterranean region is frequently limited by soil water availability. To study plant responses to water deficit under such conditions is important for improving crop management and for selecting better yielding forage shrub species. Pre-dawn leaf water potential (Ψpd), plant leaf area (PLA), leaf area per stem (LAs), leaf appearance rate (LAR1;), leaf senescence rate (LSR), individual leaf area (LA) and maximal leaf elongation rate (LER) were studied throughout the year for Medicago arborea (MA) and Medicago citrina (MC) under irrigated (control) and low rainfall field conditions, at the experimental field site of the University of the Balearic Islands in Spain. With irrigation, the highest LA and LER were observed in autumn and spring and the lowest in winter and summer. LAR; was similar for both species in autumn and winter. Throughout the spring, LAR1 was higher for MC compared to MA. PLA was similar for both species during the autumn, winter and spring seasons; however, during the summer PLA of MA was significantly reduced by 53%. This decline was attributed to higher leaf senescence during seed maturity. As a consequence, MC maintained higher leaf area (∼ 5 m2 plant−1) than MA (3 m2 plant−1). Under natural field conditions, soil water deficit increased from February to late August. The main effect of water stress was a marked reduction in LAR1, LA and LER reflected in lower LAs and PLA. Leaf area was severely reduced for both species during the summer, but much more intensively in MA, which developed full leaf senescence. Thus, MC maintained higher PLA than MA (0.5 m2 compared to 0.0 m2). Throughout the year, but especially in the driest months, MC was superior to MA in leaf growth parameters and PLA. 相似文献
94.
Environmental contamination with various insecticides remains an actual problem. In this connection, investigation of toxicologic hazard of insecticides is essential. In this work, effects of the type II pyrethroids (fenvalerate, cypermethrin and deltamethrin) on Daphnia magna were determined. It was found for the first time that not only low doses (up to 10(-12) M) of the above-mentioned chemicals but also extremely low doses (up to 10(-29) M) showed toxicological action on the invertebrates both at optimal (23 +/- 0.5 degrees C) and increased (28 +/- 0.5 degrees C) temperature. At higher temperature, toxic effects were more pronounced. 相似文献
95.
A M PRADOS-LIGERO J BASCÓN-FERNANDEZ C CALVET-PINÓS C CORPAS-HERVÍAS A LARA RUIZ J M MELERO-VARA M J BASALLOTE-UREBA 《The Annals of applied biology》2002,140(3):247-253
Soil solarisation was consistently efficacious in reducing inoculum density to undetectable levels in a field naturally‐infested with Sclerotium cepivorum. This treatment delayed epidemic onset of white rot of garlic 2–3 months as compared with the untreated control or the inoculation of planting furrows with Glomus intraradices. Furthermore, significant reductions of disease incidence and of the standardised AUDPC were also observed in solarised plots, resulting in quantitative and qualitative yield improvement. Similar effects were observed in plots planted with tebuconazole‐treated cloves, confirming previous results, whereas Trichoderma harzianum was ineffective as a biocontrol agent, when applied to planting furrows. The inoculation of plots with G. intraradices before planting, in three consecutive years, was neither effective for disease control nor on the development of garlic, although the root systems of garlic plants from all the experimental treatments were heavily mycorrhizal at harvest, indicating the presence of native arbuscular mycorrhizal propagules in the soil and their survival after soil solarisation. 相似文献
96.
Hominins are smaller, slower, and weaker than most large mammals, yet they have been eating meat from freshly killed large mammals since before the invention of sophisticated weaponry. It is thought that they could have achieved this seemingly impossible feat through persistence hunting, a practice powered by endurance running. Essentially, one or more hunters pursue a prey animal in the heat of the day until it reaches the point of hyperthermia. This allows a hunter to safely kill the weakened animal at close range using methods such as beating, strangling, or spearing. The energy balance of this approach to getting food is controversial and has not been calculated previously. We examined the energy costs and gains of persistence hunting through several energy returned on investment (EROI) calculations based on synthesizing available field and laboratory data on the energy used by the hunters and the energy returned from the greater kudu (Tragelaphus strepsiceros). We estimate that the EROI of these hunter-gatherers hunting a kudu ranged from 26:1 to 69:1. The net energy gained from such an effort would sustain an average sized !Kung family for 6.7 to 11.2 days. The “profit” energy within these ranges would have supported the early human societies that practiced persistence hunting, contributing to the often-noted “leisure” characterizing many foraging societies (Sahlins 1974). 相似文献
97.
98.
A. Kochevenko Y. Ratushnyak D. Kornyeyev O. Stasik L. Porublyova S. Kochubey T. Suprunova Y. Gleba 《Plant cell reports》2000,19(6):588-597
Fertile cybrid plants of three subclones, B1A, B3A, B4A were regenerated from the single colony obtained after the fusion
of mesophyll protoplasts of plastome chlorophyll-deficient mutant Lycopersicon peruvianum var 'dentatum' (line 3767) and γ-irradiated mesophyll protoplasts of L. esculentum (cv 'Quedlinburger Frühe Liebe'). Cytogenetic, isozyme, RAPD, morphological and restriction analyses all showed that the
subclones had the nuclear genome of L. peruvianum var 'dentatum' and plastome genome of L. esculentum, while the mitochondrial genome was altered. No phenotypical traits that could be taken as evidence of plastome-genome incompatibility
in the cybrid subclones were observed. Genetic functionality of all subclones was proven by the backcrossing analysis. To
study the functionality of the cybrid plants we also carried out an analysis of their photosynthetic system. Data on chlorophyll-a
and -b content, analyses of the fluorescence induction curves, intensity of CO2 assimilation, pigment-protein complexes and polypeptides of thylakoid membranes showed the absence of structural and functional
abnormalities in the photosynthetic apparatus of the cybrid plants. We concluded that the plastome of L. esculentum is able to effectively interract with the nuclear genome of L. peruvianum var 'dentatum' and together with the recombined chondriome can support genetic functionality of cybrid plants of the peruvianum tomato.
Received: 5 October 1998 / Revision received: 28 May 1999 / Accepted: 12 July 1999 相似文献
99.
Brendan AS McIntyre Cantas Alev Hiroshi Tarui Lars M Jakt Guojun Sheng 《BMC developmental biology》2008,8(1):21
Background
In addition to erythrocytes, embryonic blood contains other differentiated cell lineages and potential progenitor or stem cells homed to changing niches as the embryo develops. Using chicken as a model system, we have isolated an enriched pool of circulating non red blood cells (nRBCs) from E4 and E6 embryos; a transition period when definitive hematopoietic lineages are being specified in the peri-aortic region. 相似文献100.