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81.
The purpose of the study was to evaluate the quality of Toki-shakuyaku-san extract granules (TJ-23) using chemiluminescence (CL). A linear relationship was obtained between the log value of the CL of TJ-23 and the reaction temperature. An excellent correlation (r= 0.999) was found between the slope of this curve (ΔA) and the colour intensity due to the browning reaction occurring at the early stage of the Maillard reaction.  相似文献   
82.
《Journal of Asia》2023,26(3):102080
Light traps equipped with light emitting diodes (LEDs) have been applied to manage some phototactic insect pests. The diamondback moth, Plutella xylostella, is a cosmopolitan insect pest to be seriously harmful to many cruciferous plants. The present research focused on evaluating the phototactic behavior responses of the moths to several wavelengths and photon flux densities of LED lights under laboratory and field conditions. The results from the laboratory showed that the highest phototactic behavior responses of P. xylostella moths were recorded for UV (380 nm) LED light under 1.5 µmol m−2 s−1 and 2.5 µmol m−2 s−1. The moths were more attracted to light traps equipped with 4 LEDs and 6 LEDs of 380 nm, respectively, between 20:00 and 22:00 than the other groups and night times in the field. The finding from the field was consistent with the results from the laboratory. We found that the 380 nm LED light results in the strongest attraction rate of the moths by 92.4 % and the moths caught in light trap with the UV LEDs was 1.62 times more than that with a black light. These data clearly demonstrate that P. xylostella moths have a high sensitivity to 380 nm, therefore, a 380 nm LED light trap could be useful for monitoring and controlling the moths.  相似文献   
83.
Increasing exposure to climate warming-related drought and heat threatens forest vitality in many regions on earth, with the trees' vulnerability likely depending on local climatic aridity, recent climate trends, edaphic conditions, and the drought acclimatization and adaptation of populations. Studies exploring tree species' vulnerability to climate change often have a local focus or model the species' entire distribution range, which hampers the separation of climatic and edaphic drivers of drought and heat vulnerability. We compared recent radial growth trends and the sensitivity of growth to drought and heat in central populations of a widespread and naturally dominant tree species in Europe, European beech (Fagus sylvatica), at 30 forest sites across a steep precipitation gradient (500–850 mm year−1) of short length to assess the species' adaptive potential. Size-standardized basal area increment remained more constant during the period of accelerated warming since the early 1980s in populations with >360 mm growing season precipitation (April–September), while growth trends were negative at sites with <360 mm. Climatic drought in June appeared as the most influential climatic factor affecting radial growth, with a stronger effect at drier sites. A decadal decrease in the climatic water balance of the summer was identified as the most important factor leading to growth decline, which is amplified by higher stem densities. Inter-annual growth variability has increased since the early 1980s, and variability is generally higher at drier and sandier sites. Similarly, within-population growth synchrony is higher at sandier sites and has increased with a decrease in the June climatic water balance. Our results caution against predicting the drought vulnerability of trees solely from climate projections, as soil properties emerged as an important modulating factor. We conclude that beech is facing recent growth decline at drier sites in the centre of its distribution range, driven by climate change-related climate aridification.  相似文献   
84.
 不同放牧强度下高寒灌丛植物在生长发育、生理生态,物质生产和群落结构等方面主要有以下变化:1.在高寒灌丛草场,禾草类、莎草类和灌丛类植物的叶面积指数和平均生长速率随着放牧强度的减轻而增大;随着放牧强度的增加而减小。植株平均高度,植被盖度水平也与放牧强度呈负相关(p<0.01)。2.各项生长分析参数中:叶面积比率(LAR)、叶面积干重比(SLA)和叶干重比(LWR)与放牧强度之间存在负相关。叶面积指数(LAI)与地上生物量呈正相关(p<0.5),地上部现存在量与放牧强度呈负相关(p<0.01)。3.不同放牧强度条件下,高寒灌丛中的禾草类、莎草类、灌丛类和杂类草植物的种类组成和数量变化明显。其中禾草类和莎草类、灌丛类植物的生物量和种类组成比例在重度放牧下减少,在轻度放牧下增大。反之,重度放牧下杂类草的组成和数量明显增加,而轻度放牧下其比例降低。  相似文献   
85.
The response properties of R1–6 type photoreceptors of the blowfly (Calliphora vicina) were investigated using 1- to 600-ms light steps with contrasts from -1.00 to +1.12 at different adapting backgrounds. To prevent activation of voltage-dependent K+-channels, some photoreceptors were treated with ionophoretically injected tetraethylammonium. The linearity and time-course of the photoresponses depended on the adapting background and the duration of the contrast stimulus. At low backgrounds photoresponses were approximately linear regardless of the contrast step duration. However, at higher backgrounds photoreceptors produced, with long contrast steps of opposite polarities, larger and slower hyperpolarizing responses than depolarizing ones, but linear responses with equal time-courses to transient (2ms) contrast changes. The early rising phases of photoresponses were independent of the contrast signal duration, deviated to the same extent from the steady-state potential and steepened as the value of contrast was increased. The photoreceptor contrast gain increased with the background, but its value depended on the duration, the magnitude, and the polarity of the contrast step. Tetraethylammonium linearised the photoreceptor membrane, increased and delayed photoresponses probably by blocking the shunting of the outwardly rectifying potassium channels. These effects did not strongly influence on the photoreceptors' characteristic non-linear contrast dependence on light adaptation.Abbreviations LED light emitting diode - TEA tetraethylammonium ion  相似文献   
86.
Intracellular recordings and dye injections were used to examine mutual coupling among slow abdominal postural motoneurons in the 4th abdominal ganglion in crayfish (Procambarus clarkii). Intracellular current injection into one motoneuron altered the spike firing rate of some of its synergists. Depending on the polarity of the injected current, the premotor effect on the synergists was excitatory or inhibitory. The magnitude of the effect was intensity dependent. No dye coupling was found among the motoneurons following injection of Lucifer yellow. The morphological basis of the coupling was examined by differential filling of motoneuron pairs, one with horseradish peroxidase and the other with Lucifer yellow. The stained motoneurons were simultaneously visualized under light microscopy to determine the proximity of their differently colored dendrites. It was thus possible to locate the site of the presumed monosynaptic contacts between them. Combined physiological and morphological evidence suggests that these neurons are mutually coupled, forming part of an integrative system for abdominal posture control in crayfish.  相似文献   
87.
Mnemiopsin 1 (Mn1) and Mnemiopsin 2 (Mn2) are photoproteins found in Mnemiopsis leidyi. We have tried to answer the question of whether the structural features of photoproteins can explain the observed activity data. According to the activity measurements data, they have the same characteristic wavelength. However, the initial intensity of Mn2 is significantly higher than that of Mn1, and decay time of Mn1 (0.92 s−1) is lower than that of Mn2 (1.46 s−1). The phylogenetic analysis demonstrates that, compared with Obelin and Aequorin from Obelia longissima and Aequorea victoria, respectively, a gene modification event may have caused the expansion of the N-terminal side of all photoproteins from M. leidyi. An in silico study has shown that the stability of the photoprotein–substrate complex of Mn2 is higher than that of Mn1, indicating a higher affinity of the substrate for Mn2 compared with Mn1. It was revealed that the active EF-hand loops 1 and III in Mn2 is locally more rigid compared with those in Mn1. We concluded that different stability of the photoprotein complexes leads to different initial intensity. While different patterns of the local dynamics of loops I and III may influence the decay rate.  相似文献   
88.
黄翀  王淑璇  李贺 《生态学报》2023,43(13):5453-5465
滨海湿地是迁徙水鸟的重要迁飞通道和主要栖息地,评估沿海迁徙水鸟栖息地适宜性及变化态势能为栖息地的合理规划与管理提供科学参考,对迁徙水鸟的保护有重要意义。选择紧邻城市和乡村的深圳湾和雷州湾为研究区,在水鸟栖息地生态系统类型分类的基础上,通过层次分析法确定水鸟栖息地适宜性评价因子,设计栖息地、食物、水分、人类干扰条件及其子类的权重,对栖息地适宜性进行等级划分,分析比较2010-2019年迁徙水鸟栖息地适宜性的时空分布差异,探索适宜性变化差异的原因并给出合理化建议。结果表明:(1)2010-2019年深圳湾有193.4 hm2强干扰区域转变化为中等及弱干扰;雷州湾有16.36 hm2的中等干扰转化为弱、无干扰;(2)深圳湾栖息地适宜性以中等适宜类型为主,2010年和2019年面积占比分别为83.74%和88.71%;雷州湾栖息地适宜性主要以较适宜和中等适宜类型为主,2010年面积占比为86.72%,2010-2019年面积占比基本不变,总体适宜性高于深圳湾。(3)2010-2019年,深圳湾不适宜和较适宜面积分别减少245.54 hm2和26.37 hm2,均转化为中等适宜类型;雷州湾有24.31 hm2的中等和较适宜栖息地转化为适宜类型。  相似文献   
89.
李智慧  王凯  徐丽萍 《生态学报》2023,43(5):2128-2140
环境规制作为实现旅游低碳发展的重要动力之一,也是实现旅游业“碳达峰、碳中和”目标的有效路径。基于综合指数法和“自下而上”法,测度2005—2019年中国大陆30个省份(中国港澳台及西藏统计数据尚缺)的环境规制水平和旅游业碳排放强度,并借助面板回归模型和面板门槛模型探讨了环境规制对旅游业碳排放强度的影响及其区域异质性。结果表明:(1)研究期内,中国整体旅游业碳排放强度呈下降趋势;其中,中部地区下降趋势最为明显,其次分别为西部、东部和东北地区。(2)中国环境规制水平呈增长态势,其规制效应对胡焕庸线右侧的地区更为显著,并呈现出自东向西递减的梯度分布特征。(3)中国环境规制对旅游业碳排放强度存在明显的“倒逼减排”效应,但东北地区却存在一定的“绿色悖论”现象;环境规制对旅游业碳排放强度的影响存在单一阈值,当旅游能源强度小于阈值时,存在显著的“倒逼减排”效应,当旅游能源强度超过阈值时则存在“绿色悖论”效应。(4)东部地区环境规制未通过门槛效应检验;中部地区存在单个门槛值,环境规制有效促进旅游业碳排放强度的下降,不存在“绿色悖论”现象;西部和东北地区分别存在单、双门槛效应,环境规制对旅游业碳排放强度...  相似文献   
90.
城市生态环境和城市化之间的关系是城市可持续发展的关键。研究不同城市化水平下植被覆盖的长时间演变趋势,对理解城市化过程对植被生长动态的影响,城市更新以及推进城市绿化的科学管理具有重要意义。然而,目前对城市内部沿城乡梯度植被生长趋势差异的认识还比较有限。以我国城市化发展最为强烈的长三角地区为研究对象,基于2000-2020年长三角归一化植被指数数据,采用趋势分析和地理探测器方法,探究了长三角地区城市内部植被覆盖演变城乡差异,并从土地利用/覆被变化和城市化发展的角度解析其成因。研究结果表明:(1)2000-2020年长三角地区植被总体呈绿化趋势,植被明显绿化占最大比例(52.06%),轻微绿化与稳定不变地区占31.68%,零星分布的褐化区占6.82%。(2)城市老城区植被覆盖变化总体呈现返绿趋势(0.016/10 a),新城区褐化明显(-0.019/10 a),农郊区绿化突出(0.023/10 a)。在上海、南京和杭州等人口城市化水平较高的城市中,老城区土地利用变化强度最高,其绿化趋势也最高,体现了城市更新过程对绿地空间的促进作用;而在人口城市化水平相对较低的宣城、蚌埠和阜阳等城市,土地利用变化强度相对较低的农郊区也呈现明显的绿化趋势,更多的是受到区域生态保护的影响。(3)土地城市化是长三角地区老城区和新城区植被覆盖变化的主导因子,而城市化因子对农郊区解释程度总体不显著。从长三角总体区域看,城镇人口比重、不透水面积/总面积以及地区生产总值三者对植被覆盖演变存在显著影响,其中城镇人口比重影响最大。  相似文献   
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