全文获取类型
收费全文 | 1092篇 |
免费 | 47篇 |
国内免费 | 70篇 |
专业分类
化学 | 530篇 |
晶体学 | 15篇 |
力学 | 22篇 |
综合类 | 6篇 |
数学 | 6篇 |
物理学 | 72篇 |
综合类 | 558篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 30篇 |
2021年 | 44篇 |
2020年 | 46篇 |
2019年 | 24篇 |
2018年 | 20篇 |
2017年 | 26篇 |
2016年 | 31篇 |
2015年 | 41篇 |
2014年 | 63篇 |
2013年 | 66篇 |
2012年 | 45篇 |
2011年 | 56篇 |
2010年 | 44篇 |
2009年 | 79篇 |
2008年 | 50篇 |
2007年 | 66篇 |
2006年 | 62篇 |
2005年 | 51篇 |
2004年 | 52篇 |
2003年 | 44篇 |
2002年 | 30篇 |
2001年 | 28篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 19篇 |
1997年 | 12篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
排序方式: 共有1209条查询结果,搜索用时 0 毫秒
71.
Verheyen S. Blaton N. Kinget R. Van den Mooter G. 《Journal of Thermal Analysis and Calorimetry》2003,73(2):563-576
The effect of grinding on the physical properties and pharmaceutical performance of solid dispersions made of poly(ethylene)
glycol 6000 (PEG6000) and temazepam or diazepam was studied using differential scanning calorimetry (DSC), X-ray powder diffraction
and dissolution experiments. DSC-analysis of flash-cooled dispersions revealed that amorphous PEG present immediately after
grinding crystallised upon aging mainly into the twice folded modification and to a small extent into the extended form. DSC-analysis
of dispersions kept in the slab form for 1 month and subsequently ground, revealed that in the abscence of the grinding impulse
crystallisation of PEG6000 takes place in the same way as in dispersions ground immediately after preparation and then aged
for 1 month. Grinding solid dispersions immediately after preparation resulted in superior dissolution properties compared
with solid dispersions kept in the monolith-slab form and subsequently ground. This difference in dissolution properties was
found to be attributed to the drug and not to the polymer, more precisely, it was suggested that the drug particle size in
ground dispersions was smaller than in dispersions kept in the slab form and subsequently ground. These findings suggest that
grinding of solid dispersions immediately after preparation is the preparation method of choice instead of liquid filling
of hard gelatin capsules resulting in monoliths.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
72.
Production waste of primary lithium batteries constitutes a considerable secondary lithium feedstock. Although the recycling of lithium batteries is a widely studied field of research, the metallic residues of non-rechargeable lithium battery production are disposed of as waste without further recycling. The risks of handling metallic Li on a large scale typically prevent the metal from being recycled. A way out of this situation is to handle Li in an aqueous solution, from where it can be isolated as Li2CO3. However, the challenge in hydrometallurgical treatment lies in the high energy release during dissolution and generation of H2. To reduce these process-related risks, the Li sheet metal punching residues underwent oxidative thermal treatment from 300 to 400 °C prior to dissolution in water. Converting Li metal to Li2O in this initial process step results in an energy release reduction of ∼70 %. The optimal oxidation conditions have been determined by experimental design varying three factors: temperature, Li metal sheet thickness, and residence time. With 96.9±2.6 % almost the entire Li amount is converted to Li2O, after 2.5 h treatment at 400 °C for a Li sheet thickness of 1.99 mm. Final precipitation with CO2 yields 85.5±3.0 % Li2CO3. Using pure Li sheets, the product Li2CO3 is obtained in battery-grade quality (>99.5 %). Non-precipitated Li is recirculated into the process on the stage of dissolving Li2O, thus avoiding loss of material. 相似文献
73.
Four commercially available formulations containing iron, zinc, and manganese were subjected to dissolution profile testing during 60 min and the dissolution was analyzed by ion chromatography. The obtained curves were analyzed directly by principal component analysis (PCA). The main trend (87.1% of variance) was connected with average dissolution percentage over the investigated time. The second component (11.2% of variance) is connected with shape of dissolution profile. All metals behave in the similar way and the differences were connected with excipients. An additional fit was completed on 12 kinetic models: first order kinetics (4 variants), Higuchi (2 variants), Hixson-Crowell (2 variants), Korsemeyer-Peppas, Logistic (2 variants), Peppas-Sahlin, Quadratic (2 variants), Weibull (3 variants), and Zero order kinetics (2 variants). The ranking of the fitting was performed by Akaike information criteria (AIC) values with additional PCA analysis on them, an approach presented in literature for the first time. The main trend (67.4% of variance) was connected with average fit. The second (14.8% of variance) is connected with differences of fitting ability to investigated dissolution curves. This methodology brought an overall look to trends and variances inside obtained data, both the profile shape and fitting ability to particular models. 相似文献
74.
75.
台湾地区儿童虐待包括对儿童进行的身体虐待、性虐待、精神虐待及忽视。针对儿童虐待案件,台湾地区在立法层面以《儿童及少年福利与权益保护法》及《家庭暴力防治法》为主,制定了一系列对不法行为的规制与惩处措施;地区干预层面,也已建立起相当完善的地区干预防治体系,包括司法干预及行政救援。其中司法干预以民事保护令与刑事程序为主,行政救援则以“内政部”家庭暴力暨性侵害防治中心之案件行政化处理工作为重点。以地区亲权视野,对台湾地区儿童虐待的法律渊源及防治体系进行分析,旨在探寻我国内地儿童权利保护完善之策。 相似文献
76.
小额诉讼程序和速裁程序皆为我国民事诉讼简易化程序改革之产物,两者既有相同之处又有相异之点。从司法改革趋势来看,速裁程序日益凸显其实践价值,小额诉讼程序则逐渐式微。但是,不能因速裁程序之"兴盛",小额诉讼程序之"没落",而在倡举速裁程序之时,完全摒弃小额诉讼程序之功能性价值。毕竟,小额诉讼程序与速裁程序并无本质上的冲突和矛盾,两者均有值得引鉴的内在机制。所以,改进和整合小额诉讼程序和速裁程序,将小额诉讼程序置于速裁程序之中,成为速裁程序一部分更为合理。 相似文献
77.
最近两年来某些地方法院为解决"执行难"问题而进行的大胆尝试——主动执行,可以说是对以往被动司法、被动执行的司法原则和司法理念的直接挑战,在理论界与实务界引起不少争议。通过探讨表明,主动执行有其法理上的正当性与现实的必要性。 相似文献
78.
司法正义要求国家公平或公正地保护刑事诉讼中各方主体的合法利益。就中国现实情况而言.民愤在一定程度上影响了司法正义的实现。社会之所以需要刑事辩护律师,是因为他们能够为社会的发展进步提供有价值的刑事法律服务,能够为司法正义的实现提供现实支持。 相似文献
79.
我国农业保险必须实行强制性保险 总被引:2,自引:0,他引:2
匡绍君 《贵州师范大学学报(社会科学版)》2009,(2)
自20世纪80年代中期以来,我国农业保险的发展一直处于萎缩甚至停滞状态.为解决这一问题,我国在实行政策性农业保险的同时,还必须实行强制性保险,这也符合保险所要求的大数法则、分散原理和规模经济性.而且,政策支持要考虑区域差异性. 相似文献
80.
黎慢 《贵州工业大学学报(自然科学版)》1989,18(1):91-96
本试验专门从铝土矿中采集并分离,制得了富含高岭石的矿块,用该矿块定量地研究了温度、时间和石灰添加量等因素对高岭石溶解性能以及对拜耳赤泥相成分、相变化的影响,并且计算出了赤泥的相组成。 相似文献