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101.
小麦冠层反射光谱与植株水分状况的关系 总被引:21,自引:3,他引:21
研究了不同土壤水、氮条件下小麦冠层光谱反射特征与叶片和植株水分状况的相关性.结果表明,在小麦主要生育期,冠层叶片含水率与460~510、610~680和1480~1500nm波段范围内的光谱反射率有较高的相关性,植株含水率与810~870nm波段范围内的光谱反射率密切相关.在整个生长期内,小麦冠层叶片含水率与460~1500nm波段范围内的光谱反射率均有良好相关性,植株含水率与560~1480nm波段范围内光谱反射率的相关性均达到极显著水平.冠层叶片(CL)、上层叶(UL)和下层叶片(LL)含水率与光谱指数的相关程度为CL>LL>UL.冠层叶片和植株含水率与比值指(R(610,560))和光谱指数(R(610,560)/ND(810,610))呈极显著线性负相关,与归一化指数((R810-R610)/(R810+R610))呈极显著线性正相关.其中,用光谱指数(R(610,560)/ND(810,610))监测不同生育期小麦冠层叶片和植株含水率的效果最好。 相似文献
102.
崇明东滩盐沼土壤重金属含量的高光谱估算模型 总被引:5,自引:0,他引:5
高光谱遥感技术现已被广泛应用于地表矿物成份的识别以及它的含量、植物化学成份的估测,土壤调查等方面的研究。利用地物光谱仪测定了长江口崇明东滩盐沼土壤的光谱信息,根据EO-1卫星Hyperion高光谱仪的波段设置,提取各波段平均波长的光谱反射率,并结合实验室实测的土壤重金属含量,应用偏最小二乘法(PLS),预测盐沼土壤重金属含量。结果表明,盐沼土壤重金属Zn、Cr、Cu预测值与实测值相关系数分别达到0.822**、0.761**和0.775**,均为极显著相关,其实测值与预测值的平均相对误差为4%、3%和4%。研究结果可以为高光谱遥感技术反演盐沼土壤重金属含量,进一步应用空间或航空遥感进行大尺度环境污染遥感、遥测信息提取和反演提供技术支撑。 相似文献
103.
Physiological characterization of the compound eye in monarch butterflies with focus on the dorsal rim area 总被引:4,自引:0,他引:4
Julia Stalleicken Thomas Labhart Henrik Mouritsen 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(3):321-331
The spectral, angular and polarization sensitivities of photoreceptors in the compound eye of the monarch butterfly (Danaus plexippus) are examined using electrophysiological methods. Intracellular recordings reveal a spectrally homogenous population of UV
receptors with optical axes directed upwards and ≥10° to the contralateral side. Based on optical considerations and on the
opsin expression pattern (Sauman et al. 2005), we conclude that these UV receptors belong to the anatomically specialized dorsal rim area (DRA) of the eye. Photoreceptors
in the main retina with optical axes <10° contralateral or ipsilateral have maximal sensitivities in the UV (λmax≤340 nm), the blue (λmax=435 nm) or in the long-wave range (green, λmax=540 nm). The polarization sensitivity (PS) of the UV receptors in the DRA is much higher (PS=9.4) than in the UV cells (PS=2.9)
or green cells (PS=2.8) of the main retina. The physiological properties of the photoreceptors in the DRA and in the main
retina fit closely with the anatomy and the opsin expression patterns described in these eye regions. The data are discussed
in the light of present knowledge about polarized skylight navigation in Lepidopterans. 相似文献
104.
105.
Phototaxis in water fleas (Daphnia magna) is differently influenced by visible and UV light 总被引:3,自引:0,他引:3
U. C. Storz R. J. Paul 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,183(6):709-717
The effects of vertical illumination with monochromatic lights on phototaxis of Daphnia magna in a test chamber were determined at five levels of equal quantal flux density (between 188 and 6.42 · 10−5 nEinstein). Visible adaptation light (500 nm) and subsequent spectral test light had the same quantal flux density. The animals
reacted to ultraviolet light (260–380 nm) with negative phototaxis, whereas visible light (420–600 nm) caused positive phototaxis.
Action spectra were determined, based on the evaluation of different parameters of phototactic behavior. The maximum spectral
sensitivity in the ultraviolet was found at 340 nm. The maximum spectral efficiency in the visible varied in dependence on
light intensity. Ecological consequences of the results are discussed.
Accepted: 3 August 1998 相似文献
106.
Mating in the black soldier fly (BSF) is a visually mediated behaviour that under natural conditions occurs in full sunlight. Artificial light conditions promoting mating by BSF were designed based on the spectral characteristics of the compound eye retina. Electrophysiological measurements revealed that BSF ommatidia contained UV-, blue- and green-sensitive photoreceptor cells, allowing trichromatic vision. An illumination system for indoor breeding based on UV, blue and green LEDs was designed and its efficiency was compared with illumination by fluorescent tubes which have been successfully used to sustain a BSF colony for five years. Illumination by LEDs and the fluorescent tubes yielded equal numbers of egg clutches, however, the LED illumination resulted in significantly more larvae. The possibilities to optimize the current LED illumination system to better approximate the skylight illuminant and potentially optimize the larval yield are discussed. 相似文献
107.
108.
Megha Munjal 《Inorganica chimica acta》2011,377(1):144-154
The present work shows three new amide-based ligands H2L1, H2L2 and H2L3 and their nickel and copper complexes. The X-ray structural analysis substantiate that the ligands constitute a square-based basal plane around the metal center. The crystal structures also show interesting solid state packing due to hydrogen-bonding and various weak C?H interactions. The solution-based spectral studies support the solid-state geometry observed for these complexes. The electrochemical results show that the Ni3+/2+ and Cu3+/2+ redox couple primarily depends on the N4 donors composed of Namide and Namine atoms. It was observed that the ligands H2L1 and H2L2 are better suited to stabilize the Cu(III) species whereas ligand H2L3 is ideal for the stabilization of Ni(III) species. On the basis of electrochemical findings, transient Ni3+ species were generated and characterized by the absorption spectroscopy. 相似文献
109.
Myopia is a common ophthalmic deficiency. The structure and function of choroid layer is assumed to be associated with myopia. In this study, a laboratory developed spectral domain optical coherence tomography scanning system is used to image human eyes. The axial resolution of the system is about 7 μm, and the acquisition rate is 100 kHz. Firstly, a cross-sectional image was acquired by averaging 100 images from imaging posterior segment of each eye. The choroid thickness was measured by 11 discrete points. The average thickness of normal human eyes was (0.296 ± 0.126) mm, whereas the average choroid thickness of myopic eyes was (0.220 ± 0.095) mm. Afterwards, the T test is used to calculate the data statistically. The analysis of the final result is based on the average thickness measured and the thickness of each measuring point. There was a significant difference in choroid thickness between myopia and normal eyes (P value < 0.01), which indicates that the choroid thickness of myopia was significantly thinner than that of normal eyes. Besides, there are findings that the choroidal thickness in nasal side is thinner than that in the fovea and temporal side in each eye. The choroidal thickness on temporal side in myopia eye has the most significant difference comparing with that in normal eye. The comprehensive evaluation of myopia and normal choroidal thickness using spectral domain optical coherence tomography may provide an important reference for the development of medical methods for diagnosis and treatment of myopia. 相似文献
110.
It is basic question in biology and other fields to identify the characteristic properties that on one hand are shared by
structures from a particular realm, like gene regulation, protein–protein interaction or neural networks or foodwebs, and
that on the other hand distinguish them from other structures.
We introduce and apply a general method, based on the spectrum of the normalized
graph Laplacian, that yields representations, the spectral plots, that allow us
to find and visualize such properties systematically. We present such
visualizations for a wide range of biological networks and compare them with
those for networks derived from theoretical schemes. The differences that we find
are quite striking and suggest that the search for universal properties of
biological networks should be complemented by an understanding of more specific
features of biological organization principles at different scales.
相似文献
Jürgen JostEmail: |