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91.
92.
硼硅酸盐生物玻璃的制备及其体外生物活性和降解性 总被引:7,自引:0,他引:7
采用熔融法制备了NaO-CaO-SiO2-P2O5-B2O3玻璃,用质量损失分析、pH值测定和X射线衍射、电子显微镜以及电感耦合等离子体离子浓度分析法表征玻璃与稀K2HPO4溶液的类生物反应,研究了这类玻璃的生物活性和生物降解性.结果表明:当玻璃中B2O3/SiO2的摩尔比为3:1时,生物活性较好.随着B2O3与SiO2的摩尔比减小,玻璃的降解速度变慢,获得的羟基磷灰石结晶度较低.利用此特性可控制生物玻璃的降解速度,从而与骨细胞生长速度相匹配.因此,此类硼硅酸盐生物活性玻璃有望在硬组织工程支架材料中得到应用. 相似文献
93.
研究了呼吸法、基质去除法、微生物细胞增殖法等4种有关好氧生物降解酸性偶氮染料的测定方法,为污染物的生物降解性能研究以及开发生物处理技术提供参考和实践指导. 相似文献
94.
Biodegradable copolymers of 2‐methylene‐1,3‐dioxepane (MDO) and styrene (ST) were synthesized by free‐radical copolymerization using di‐t‐butyl peroxide (DTBP) as the initiator. The copolymers containing ester units were characterized by Fourier transform infrared (FTIR), 1H‐NMR, and 13C‐NMR spectroscopy. Their molecular weight and polydispersity index were determined by gel permeation chromatography (GPC). In vitro enzymatic degradation of poly(MDO‐co‐ST) was performed at 37°C in phosphate buffer solution (PBS, pH = 7.4) in the presence of Pseudomonas lipase or crude enzyme extracted from earthworm. The experiment showed that incorporating ester units into C? C backbone chain of polystyrene would result in a biodegradable copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1146–1151, 2007 相似文献
95.
Urszula Laska A. Wilk Irena Maliszewska Ludwik Syper 《Journal of surfactants and detergents》2006,9(2):115-124
In the search for environmentally safe surfactants made from inexpensive and renewable sources, the interest has mainly been
focused on new saccharide derivatives. This report describes the synthesis of newly designed nonionic gemini compounds comprising
two reduced sugar headgroups, two alkyl tails, and a 1,1′-ethylenebisurea entity as the spacer linking two amphiphilic glucose-derived
moieties. Thus, the series of N,N′-bis[(3-alkyl-3-deoxy-d-glucitol)ureido]ethylenediamines (bis(CnGT), with Cn=n-C9H9, n-C6-H13, n-C8H17, n-C10H21, or n-C12H25), were prepared using a convenient procedure starting from easily accessible reagents such as d-glucose, n-alkylamines, urea, and ethylenediamine. Their structure and purity were confirmed by means of elemental analysis, electrospray
ionization mass spectrometry, and 1H and 13C nuclear magnetic resonance spectroscopy. Additionally, the present contribution introduces selected properties of these
surfactants, including their thermotropic behavior and biological properties. The presence of two phase transition points,
determined using the differential scanning calorimetry method, indicates liquid-crystalline mesophase formation upon heating.
Furthermore, using the closed-bottle test (OECD Guideline 301D) as well as the biological oxygen demand test for insoluble
substances for biodegradability measurements, it has been concluded that the tested glucose-derived gemini structures achieve
more than 60% biodegradation after 64–75 test days. All tested surfactants were practically nontoxic to bacteria, yeast, and
molds. Owing to their fitting aggregation ability as well as their nontoxicity, they constitute an interesting group of surfactants
for various applications. 相似文献
96.
Linear alkylbenzene 总被引:1,自引:0,他引:1
J. L. G. de Almeida M. Dufaux Y. Ben Taarit C. Naccache 《Journal of the American Oil Chemists' Society》1994,71(7):675-694
Linear alkylbenzene (LAB) was introduced in the mid-1960s as a raw material for cleaning products. Since then, continuing
and explosive research on its biodegradation and on its environmental and human toxicity has been performed. The efficiency
of linear alkylbenzene sulfonate as surfactant is clearly established, and it is one of the safest and most cost-effective
products in widespread commercial use. The aim of the present paper is to survey the most important developments and understandings
of the chemistry of LAB production and of its physical and environmental properties. The expected consequence of this analytical
survey is to envisage the continuous challenges for the detergents industry in catalytic production of LAB, better control
of selectivity, replacement of corrosive and mineral liquid acid catalyst by heterogeneous acid catalyst and the maintenance
of competitiveness of LAB with respect to natural alcohols. 相似文献
97.
陶帅 《杭州电子科技大学学报》2011,(4):177-180
锅炉的炉温控制一直是工业生产中的关键环节,锅炉对象具有强耦合、大延时、大惯性特征.传统PID控制由于模型匹配不佳在实际操作上会有较大的温度波动.该文将模糊数学与预测控制相结合应用在锅炉炉温的控制上,并与传统的控制方法进行了比对,仿真结果表明该方法能解决炉温控制波动较大的难题,对锅炉炉温这一类大延时系统有较好的适用性. 相似文献
98.
矿井涌水量预测方法的发展 总被引:12,自引:0,他引:12
对矿井涌水量的多种预测及计算方法进行分析和总结,将各种方法的应用范围与限制进行综合分析,探讨各方法的改进,进行实用性的评价;确定性数学模型法和不确定性方法相结合的方法将是矿井涌水量预测计算的主要发展方向;提出与一些发展迅速的新技术相结合进行矿井涌水量预测的可能性。 相似文献
99.
100.
二级处理出水中有机物的分级特性 总被引:1,自引:0,他引:1
为研究二级出水中有机物的化学特性,以哈尔滨市W污水处理厂为研究对象,利用XAD树脂将二级处理出水中的有机物分级为5个组分:疏水性有机酸(HPO-A)、疏水性中性有机物(HPO-N)、过渡亲水性有机酸(TPI-A)、过渡亲水性中性有机物(TPI-N)和亲水性有机物(HPI).采用氯化反应实验、可生物降解溶解性有机碳和尺寸分布测定,以及紫外和红外光谱分析考察二级处理出水中不同有机组分的特性.结果表明:HPO-A是加氯消毒时产生三卤甲烷的主要有机组分.各有机组分中,溶解性有机碳(DOC)(<0.025μm)均是主要的有机碳形式和主要的三卤甲烷前体物.各组分的可生化性为:HPI>TPI-A>HPO-A>TPI-N>HPO-N.各组分的芳香性为:HPO-N>HPO-A>TPI-N>TPI-A>HPI.HPO-N和TPI-N中碳氢化合物的含量较高.在二级处理出水中,HPO-A和HPI的含量相对较高,是主要的有机组分.此外,不同有机组分的化学特性不同. 相似文献