全文获取类型
收费全文 | 224篇 |
免费 | 61篇 |
国内免费 | 28篇 |
专业分类
化学 | 95篇 |
晶体学 | 1篇 |
力学 | 24篇 |
综合类 | 1篇 |
数学 | 53篇 |
物理学 | 139篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 9篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 19篇 |
2013年 | 21篇 |
2012年 | 34篇 |
2011年 | 32篇 |
2010年 | 32篇 |
2009年 | 17篇 |
2008年 | 11篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有313条查询结果,搜索用时 15 毫秒
71.
电解还原法是近年来国际上逐步使用的一种新的卤化银颗粒尺寸和分布测定的方法.用此方法,我们研制了我国第一台微机化的测量仪。这台仪器可以测量直径从0.1μm至40μm的所有各种卤化银颗粒,而且全部操作,包括信号的提取、识别、数字化转换以及数据处理都是自动进行。与过去常用的测量方法,如电镜图象分析法、离心沉降法以及激光散射法相比,此方法测量快速,测量精度高并且设备投资少,操作方便.此外,我们还对电解法与电镜法的测试结果作了比较。 相似文献
72.
The compositional homogeneity of a poly (ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer sample was found to have a uniform composition as a function of elution volume over the major portion of sample from GPC method. However within one elution fraction, the copolymer chains, although having the same hydrodynamic volume, may have some difference in composition. Two fractions with different composition were obtained by precipitation in ethanol. Some low molar mass copolymers were also separated by a TLC technique from the copolymer sample. 相似文献
73.
Xiaoxiao Dong Hong Zhao Zhihang Wang Miray Ouzounian Travis Shihao Hu Yongjian Guo Lipeng Zhang Quan Xu 《中国化学快报》1990,30(12):2333-2337
Enhanced dry self surfaces were fabricated which could dislodge up to 24.6% of contaminated particles with as few as 4 steps. 相似文献
74.
通过对广东医学院第二附属医院辖区海滨管区2003-01-01至2005-12-31出生的儿童559人免疫后检测其乙肝病毒表面抗体(抗-HBs),了解乙型肝炎疫苗(HepB)免疫成功率。结果表明,免疫成功率为84.26%,比2002年广东省调查儿童免疫后抗-HBs阳转率(62.18%)明显提高。提示HepB有较好的免疫效果,因此提高新生儿的HepB全程接种率和HepB第1针及时接种率,是控制乙肝的关键。 相似文献
75.
Chenchen Zhou He Jia Shuaishuai Liang Yongjian Li Jiang Li Haosheng Chen 《Journal of polymer science. Part A, Polymer chemistry》2022,60(11):1750-1757
Polyhedral milliparticles (PMPs) have promising applications in self-assembly, tissue engineering, mechanical engineering, and photonics. The shapes and sizes of the PMPs have great impact on their functions. To date, the reported methods for adjusting the shapes and sizes of PMPs are still limited. Especially, it remains a challenge to fabricate the PMPs with high asymmetry. Here, we present a facile and efficient approach that focuses on the alteration of the relative positions between the microchannel and the UV light to tailor the shaping process of the PMPs. By tuning the rotation angle and translation displacement, a variety of monodisperse PMPs with both centrosymmetric and noncentrosymmetrical structures are synthesized, including tetrahedra, pentahedra, hexahedra, and so forth. Moreover, the polymeric PMPs are loaded with silica nanoparticles and further sintered into silica. The obtained silica PMPs hold great potential for the applications such as machining tools, abrasives, and electronics. 相似文献
76.
77.
We introduce the definition of pseudoorthoalgebras and discuss some relationships between orthomodular lattices and pseudoorthoalgebras.
Then we study the conditions that a pseudoeffect algebra is isomorphic to an “internal direct product” of ideals generated
by orthogonal principal elements. At last, we give some characterizations of central elements in pseudoeffect algebras. 相似文献
78.
79.
80.
ZHU Zhiyan ZHU Zhenghe TANG Changhuan TANG Yongjian & GAO Tao . Institute of Atomic Molecular Physics Sichuan University Chengdu China . China Academy of Engineering Physics Mianyang China 《中国科学G辑(英文版)》2005,48(5):575-584
The ionic charge state distribution is an important diagnostics parameter for laser in-ertia confinement fusion (LICF). It is usually obtained by solving Saha equation or using some other models, such as local thermodynamic equilibrium (LTE), corona equilibrium (CE), collision-radiation (CR) and average atom (AA); however, these methods are rather limited for high-Z element plasma. The theory of entropy fluctuation is also a pos-sible method[1]. Lawrence Livermore National Laboratory (… 相似文献