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841.
高压旋喷桩造防渗墙因其厚度均匀,强度高,质量好,被广泛运用于堤防工程的防渗加固和部分深基础工程的基坑支护,但施工中环境污染严重。根据高喷灌浆施工的工艺特点。结合长江重要堤防隐蔽工程环境保护实践,探讨了高喷灌浆施工环境污染及控制措施。  相似文献   
842.

Objective

To develop a realistic simulation model for laparotomy-assisted fetoscopic spina bifida aperta (SBa) surgery, to be used for training purposes and preoperative planning.

Methods

The predefined general requirement was a realistic model of an exteriorized uterus, allowing all neurosurgical steps of the intervention. The uterus was modelled using ultrasound and MRI images of a 25 weeks’ gravid uterus, consisting of flexible polyurethane foam coated with pigmented silicone. The fetal model, contained an opening on the dorsal side for a customizable spinal insert with all the aspects of a SBa, including a cele, placode, and myofascial and skin layer. The model was assessed in a series of validation experiments.

Results

Production costs are low, uterus and fetus are reusable. Placental localization and the level and size of the spinal defect are adjustable, enabling case-specific adaptations. All aspects of the simulator were scored close to realistic or higher for both appearance and functional capacities.

Conclusions

This innovative model provides an excellent training opportunity for centers that are starting a fetoscopic SBa repair program. It is the first simulation model with adjustable spinal defect and placental localisation. Further objective validation is required, but the potential for using this model in preoperative planning is promising.  相似文献   
843.
The low activity of Anammox bacteria at low temperatures and competition from nitrite oxidation bacteria(NOB) when treating low strength wastewater have been major bottlenecks in implementing Anammox in mainstream wastewater treatment. By intermittent high strength feeding(IHSF) and stepwise temperature reduction, stable operation of a granular Anammox reactor was realized at low temperatures(down to 15°C) for 28 days when treating low strength synthetic wastewater. The nitrogen loading rate reached 1.23–1.34 kgN/m~3/day,and the total nitrogen removal rate reached 0.71–0.98 kgN/m~3/day. The IHSF enriched the Anammox sludge in high strength cycles and compensated for sludge loss in low strength cycles, and the high concentration of ammonium in high strength cycles inhibited NOB. The 16 SrRNA gene sequencing results revealed that Candidatus Kuenenia was predominant in the reactor at low temperatures.  相似文献   
844.
为探讨外源微生物对枸杞枝条粉基质化发酵堆体腐熟进程的影响,采用随机区组设计〔T1(CK),枸杞枝条粉150 kg;T2,枸杞枝条粉150 kg+尿素4.15 kg;T3,T2+粗纤维降解菌Ⅰ 75 g;T4,T2+粗纤维降解菌Ⅱ 75 g;T5,T2+锯末专用复合益菌75 g;T6,T2+EM菌液75 g;T7,T2+纤维素酶制剂75 g〕,以尿素为氮源,研究添加外源微生物对枸杞枝条粉基质化发酵过程中发酵指标参数的影响.结果表明:堆腐发酵至第6天时,各处理组的温度均达到最高值,其中,T3的温度达到68.2 ℃,T2~T7内部温度超过50 ℃的时间依次为6、9、9、7、8、7 d.外源微生物菌剂的施用增加了枸杞枝条粉腐熟发酵后的湿容重、干容重、总孔隙度、通气孔隙、持水孔隙.至发酵结束后,各处理组的湿容重在0.43~0.47 g/cm3之间,T6的增幅最大.堆腐发酵过程中w(NH4+-N)变化呈先增后减的变化规律,发酵至第21天时,T4达784.81 mg/kg;w(NO3--N)呈逐渐增加的趋势,在发酵14~49 d之间的增幅最大,其中,T3的平均日增加值最大,为16.02 mg/(kg·d),而发酵70 d后各处理组w(NO3--N)逐渐趋于平稳.发酵前21 d w(TOC)呈近直线下降,发酵前14 d w(TN)呈直线上升;堆腐发酵至第49天时,T2~T7的GI(germination index,发芽指数)均高于50%,其中,T7为73.92%,较T1(CK)高出26.52%;发酵至第91天时,T1~T7的GI均超过85%.研究显示,枸杞枝条发酵堆体基质化过程中添加尿素+粗纤维降解菌Ⅰ(Ⅱ)、尿素+EM菌液、尿素+锯末专用复合益菌等更有助于加快基质化进程、缩短发酵时间、提高发酵效率,可为枸杞枝条基质化工厂利用提供理论支撑.   相似文献   
845.
以Landsat ETM/ TM影像为主要数据源,采用人机交互的方式提取了1990~2017年间6期乐清湾海岸线。利用马尔科夫矩阵法计算了滩涂转化规律,并按照年份进行岸线和海岸湿地变迁分析。结合当地相关资料,开展了乐清湾区域海岸线和海岸湿地变化的驱动力分析。结果表明:乐清湾岸线以人工岸线为主,岸线变化剧烈,变化速率分布不均,海岸湿地的变化整体面积变化不大,其中人工湿地主要由自然滩涂湿地转化而来,人类围填是乐清湾海岸线和海岸湿地变迁的主要因素。  相似文献   
846.
灾害损失等级划分的模糊灾度判别法   总被引:25,自引:8,他引:25  
作者应用模糊模式识别理论于灾害损失等级划分的研究,提出了模糊灾度概念,并建立了模糊灾度等级的隶属函数,从而给出了一种可用于灾害损失等级划分的模糊灾度判别法。  相似文献   
847.
Over the past decade, the Chinese government has developed several plans regulations and policy measures related to the development of renewable energy technologies and has implemented a series of pilot projects. Chinese policymakers have spent several years studying how renewable energy policy models that have been used internationally could be implemented in China. Programs are currently underway to implement pilot renewable portfolio standards, or mandatory market shares (MMS) for renewable energy, in several provinces. This paper examines the primary institutions that are involved in promoting renewable policies in China, the structure of the policies that currently are being drafted, and the status of the complementary, national-level renewable energy law being drafted to provide a legal basis for ongoing local and national-level policies. It then examines the legal requirements for promoting renewable energy legislation under the Chinese law-making system. Finally, it provides recommendations for  相似文献   
848.
大型水库是我国特大、大中型城市集中式饮用水供水源地且兼具调蓄洪峰、农田灌溉、旅游观光等多种功能.浙皖丘陵地区饮用水水库分布广泛,夏季因藻类增殖而面临一定的水质风险.本研究借助总氮(TN)、总磷(TP)、叶绿素(Chl a)、透明度(SDD)等水质参数,以及基于以上参数所构建的综合富营养指数(TLI),结合有色可溶性有机物(CDOM)吸收光谱、三维荧光光谱(EEMs)及平行因子分析法(PARAFAC),试图揭示浙皖丘陵地区共计12个饮用水库夏季营养水平、CDOM光谱特征及环境指示意义.结果表明,本研究调查水库的TLI处于25.0~48.8范围内,属中营养水平,对应a254为7.0~10.2 m-1.TP与Chl a、TLI、a254、陆源类腐殖酸C2均具有显著的相关性(p<0.01),表明TP是饮用水水库藻类增殖的主要制约因子,且与TLI关联密切.水库中Chl a浓度普遍较低,平均值为(8.4±5.7)μg·L-1,且与类酪氨酸C1、类色氨酸C3不存在显著相关性(p>0.05),说明藻源C...  相似文献   
849.
Wu  Kangming  Cui  Wang  Ren  Guofa  An  Jing  Zheng  Kewen  Zeng  Xiangying  Ouyang  Minghui  Yu  Zhiqiang 《Environmental Chemistry Letters》2023,21(4):1943-1949
Environmental Chemistry Letters - Shale gas extraction is increasing worldwide in the context of the energy crisis, yet the associated pollution by this industrial activity is poorly known. Here we...  相似文献   
850.

In this study, an approach for the facile, rapid, energy-saving, and sensitive determination of Fe3+ and Cr(VI) was developed. L-arginine/D-glucose carbon quantum dots (Arg/Glu-CQDs), with a photoluminescence quantum yield of 21%, were synthesized from L-arginine and D-glucose through a facile, hydrothermal process. The maximum emission wavelength of Arg/Glu-CQDs was observed at 450 nm, under an excitation wavelength of 365 nm. In addition, Arg/Glu-CQDs exhibited a sensitive and selective response to Fe3+ compared to Fe2+ and other metal ions. The Arg/Glu-CQDs’ fluorescence was noticeably quenched through the inner filter effect (IFE) when Arg/Glu-CQDs were mixed with Fe3+. Accordingly, the Arg/Glu-CQDs/Fe2+ system could selectively detect Cr(VI); Cr(VI) could oxidize Fe2+ to Fe3+ and quench the fluorescence. The fluorescence sensor system (i.e., the Arg/Glu-CQDs/Fe2+ system) showed high sensitivity and excellent selectivity for the detection of Fe3+ and Cr(VI) in river water samples. Satisfactory detection efficiencies ranging from 97.07 to 103.46% were obtained. The cytotoxicity of Arg/Glu-CQDs was evaluated through an MTT assay using A549 cells as the target, to extend the application of Arg/Glu-CQDs to biological systems; the MTT assay indicated that the Arg/Glu-CQDs is non-cytotoxicity. Arg/Glu-CQDs were also successfully imaged in A549 cells indicating further application possibilities in bioimaging.

Graphical abstract

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