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51.
以盘龙江滨水植物为研究对象,采取实地调查、数据收集和数据处理的研究方法,对48个样方及74个典型群落进行了深入调查。分析并总结了盘龙江滨水植物群落的特征,提出了滨水绿地植物发展的建议以供滨水绿地的景观设计与营造参考。  相似文献   
52.
工程扰动严重破坏原有地形地貌和生态植被,加剧生态环境的恶化与生态系统的退化,为减少水土流失和浅层滑坡,加速植被恢复和生态修复,对工程扰动区植被群落恢复进行研究是比较有意义的课题。研究选择生态治理后处于自然恢复期的石葵河作为研究对象,对工程扰动区不同水位的植被恢复进行季节性监测和实地调查,统计河道边坡植被恢复种类及数量、植被群落类型及其结构特征。经调查统计,常水位以上植被种类为43种,常水位以下只有17种;常水位以上Pielou均匀度指数为0.774,而常水位以下Pielou均匀度指数仅为0.397;常水位以上基本形成乔灌草垂直分布的植被群落结构,常水位以下全部是草本植物。说明水位变化对工程扰动区植被恢复有很大影响,水位变化不仅对植被恢复种类和数量有影响,而且还影响植被的生活型和生长型。  相似文献   
53.
探究河道水体中浮游动物群落分布的变化及影响因素对河道水体生物多样性的维持和水生生态系统保护具有非常重要的意义。本研究于2017年9月至2018年8月对上海徐汇区代表性的城市河道进行了环境因子和浮游动物群落结构的周年调查,共采集到浮游动物32种,其中轮虫25种,桡足类4种,枝角类3种。全年浮游动物优势种12种,包括轮虫10种,桡足类1种,枝角类1种。不同季节环境因子差异显著,浮游动物种数、丰度和生物量均为夏季最高,冬季最低。浮游动物的典范对应分析(CCA)显示,氮磷比、叶绿素a浓度和溶解氧是影响该水体浮游动物群落差异的显著环境因子。运用水质理化因子、多样性指数及浮游动物优势种进行水质污染水平评价,判断该河流水质状况属于中污型。调查结果可为上海市城市河道生态环境保护提供理论支撑。  相似文献   
54.
黑龙江水系鲤科鱼类名录   总被引:2,自引:0,他引:2  
根据《中国动物志硬骨鱼钢鲤形目(中卷)》列出黑龙江水系鲤科鱼类名录,即9亚科38属59种,订正中名称。  相似文献   
55.
流域植被作为基础的自然"本底",在构建和维护河流生态系统稳定方面有着重要作用。通过对生态恢复定义及模式的探析,以流域植物为主要分析对象,浅析其界定与特征。以郪江流域大英段生态恢复项目为载体,展开流域植物景观规划研究,阐述总体策略引导下的植物评价及规划。  相似文献   
56.
海洋沉积物中重金属含量测定样品前处理方法研究   总被引:9,自引:0,他引:9  
采用正交设计试验法对测定海洋沉积物中重金属含量的样品前处理方法进行了比较研究。结果表明。在王水、氢氟酸、高氯酸消解体系下,采用微波消解一原子吸收分光光度法测定重金属含量,省时,试剂用量少,结果准确,重现性好。  相似文献   
57.
1. Adult caddisflies were collected using non‐attracting Malaise traps at four sites on a small headwater stream from May to November 1990. Sites S1 and S2 were most natural and upstream of a reservoir; where S3 was located in the bypass channel, and S4, downstream. 2. The flight period for each species is recorded to provide baseline data. Flight activity patterns fall into two groupings: (a) species with a flight activity of 3–4 months, and (b) those species with a short flight period of up to 6 weeks. 3. Sixty‐one species from 15 families were collected, including the endangered Red Data Book species Tinodes pallidulus McLachlan. 4. Significant differences in community parameters are shown among all sites, many species apparently having local catchment areas. The influence of artificial habitats, the open bypass channel and adjacent reservoir, is clearly demonstrated. 5. The data illustrate the potential of using adult caddisflies in conservation assessment of small streams. Working with adults is taxonomically rigorous and they are useful bioindicators of the environmental quality of the valley floor corridor. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
58.
  • 1. Wastes from feed and faeces can result in the deposition of contaminants in sediments around aquaculture sites. Five types of feed pellet, a commercial fish oil and 76 sediment samples collected under and up to 100 m away from salmon aquaculture cages in the south‐western Bay of Fundy between 1998 and 2000 were analysed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides.
  • 2. Five alkylated naphthalenes (aNAs) were consistently detected in fish oil (116–180 ng g?1, per aNA), in pellets (25–51 ng g?1, dry weight, per aNA), and sediments (<1–45 ng g?1, dry weight, per aNA). Other PAHs were detected at variable levels in feed or in sediments.
  • 3. IUPAC congener 153 (a PCB) and p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE) were detected more frequently than other chlorinated targets in oil (108 ng g?1 and 176 ng g?1 respectively), feed (<1–14 ng g?1 and 1.7–28.2 ng g?1 respectively) and sediments (<0.08–3 ng g?1 and <0.5–7 ng g?1 respectively).
  • 4. Trends were observed during the first year of sediment sampling (1998), with higher organic carbon, PCBs and p,p′‐DDE levels below the cages than 50 m away. The PAHs other than aNA showed an opposite trend with distance. In 1999, levels of p,p′‐DDE and PCBs were somewhat reduced under the cages, but were detected up to 100 m away from the cages.
  • 5. Levels of aNA tended to be higher at some sites in 1999 relative to 1998, reflecting variability in feed and/or differential transport or degradation of contaminants relative to the environmental background. When detected, mean levels of PCBs and DDE were 2–10 times lower in 2000 than in 1999, and PAHs were 30–40% lower in 2000 than in 1999.
  • 6. Interpretation of the results is done cautiously, since the exact locations of the sites sampled is only known to an intermediate facilitating the work between farmers and scientists. Levels of contaminants are compared with international results, interpreted relative to potential toxicity, uptake from feed, from deposited sediments, and in the framework of an aquaculture decision‐support system published recently.
Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
59.
随着我国城市化进程的加快,城市生态环境面临着越来越严峻的考验,为了促进城市的可持续发展,构建城市绿地生态网络、维护城市生态系统的稳定性成为众多领域研究的重点。河流作为城市绿地生态网络的核心空间结构,开放空间作为绿地生态网络的基础,二者关系的研究对构建城市绿地生态网络具有重要意义。在研究河流与开放空间耦合关系的基础上,结合对城市绿地生态网络含义、功能机制、评价指标的分析,以南阳市为例,提出河流与开放空间耦合的城市绿地生态网络构建方法。  相似文献   
60.
Recreationists who encounter more people than their normative tolerance for seeing others usually feel more crowded than those encountering fewer than their norm. This research note extends this observation–norm–evaluation relationship (e.g., encounter–norm–crowding) to other evaluations and indicators. Data were from a survey of anglers on the Gulkana National Wild River in Alaska (n = 288). Respondents who encountered more people than their norm felt more crowded than those encountering fewer than their norm. When impacts from other social indicators (e.g., camping within sight or sound of other groups, fishing area competition) exceeded user norms, crowding was higher and satisfaction with overall trip quality was lower than for those experiencing less than their norms. When impacts from resource indicators (e.g., litter, impacted campsites) exceeded norms, satisfaction with both environmental quality and trip quality were lower than for those experiencing less than their norms. The encounter–norm– crowding generalization, therefore, extended to other indicators and evaluations.  相似文献   
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