全文获取类型
收费全文 | 178篇 |
免费 | 15篇 |
国内免费 | 17篇 |
专业分类
化学 | 76篇 |
晶体学 | 2篇 |
力学 | 20篇 |
综合类 | 1篇 |
数学 | 27篇 |
物理学 | 84篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 13篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 10篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 10篇 |
2004年 | 10篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 0 毫秒
1.
In this paper, by using Seshadri constants for subschemes, the author establishes a second main theorem of Nevanlinna theory for holomorphic curves intersecting closed subschemes in (weak) subgeneral position. As an application of his second main theorem,he obtain a Brody hyperbolicity result for the complement of nef effective divisors. He also give the corresponding Schmidt’s subspace theorem and arithmetic hyperbolicity result in Diophantine approximation. 相似文献
2.
辉光等离子体辅助化学气相沉积低温合成金刚石薄膜的研究 总被引:5,自引:0,他引:5
采用辉光放电等离子体增强化学气相沉积 (GP CVD)技术在低温条件下合成了高品质的亚微米金刚石薄膜 ,并通过对合成过程的实时发射光谱诊断确定了 [CH4 H2 ]系统参与金刚石合成反应的主要荷能粒子。对合成过程的研究表明 :采用这种技术能使电子增强热丝化学气相沉积 (EACVD)合成高品质金刚石薄膜的温度从 85 0℃降至 (340± 5 )℃ ;薄膜低温合成中的主要荷能粒子为CH3 、CH ,CH+ 、H 等 ,其中过饱和原子氢保证了高品质金刚石薄膜的合成 ;根据光诊断和探针测量的结果推断近表面辉光放电可在基片表面形成电偶极层 ,该偶极层是进行超常态反应的必要环境 ,并在低温合成中起重要作用 相似文献
3.
相控声波测井的模拟实验研究 总被引:14,自引:0,他引:14
自行设计和制作了两个小型的四阵元相控线阵并进行了指向性测量,通过调节施加于相邻阵元的激励信号的延迟时间,既可以改变相控线阵声波辐射器辐射能量的方向,又可以改变辐射声束主瓣的角宽,测量结果与理论计算结果的一致性良好。分别把自行制作的小型相控线阵声波辐射器和水听器置于充液微型铝质和混凝土模型井中进行了声波测井模型实验。实验结果表明,随着相邻阵元的激励信号的延迟时间的增加,相控线阵的辐射声束指向角不断变大,先后满足滑行纵波临界折射和滑行横渡临界折射条件,先后使充液井孔中的滑行纵波、滑行横波和斯通利波分别得到加强。通过恰当选择相控线阵的阵元间距和声波频率,可以明显增大相控线阵辐射声束的角宽,使其覆盖所有地层的第一临界角的范围,从而无须在井下不断调整辐射声束方向即可实现相控声波连续测井。 相似文献
4.
采用微流控技术结合悬浮聚合方法实现了百微米级含膦配体聚苯乙烯微胶囊的可控制备, 微胶囊尺寸在320~420 μm范围内可调, 且单分散性好. 扫描电子显微镜、能量散射光谱和电感耦合等离子发射光谱结果证实了其形貌和组成的均匀性及钯负载的可控性和有效性. 以溴代芳烃与苯硼酸的Suzuki偶联反应为模型反应评价了负载Pd(PPh3)4的百微米级微胶囊的催化性能, 发现其性能与文献报道的7~8 μm的同类催化剂微胶囊接近, 且均优于均相催化剂; 该催化剂经简单过滤后, 可实现多次循环使用, 未发现活性物种的流失. 该法实现了连续制备, 因而有助于提高制备的效率和可控性. 另外, 所制百微米级催化剂微胶囊在固定床反应器内具有较高催化剂浓度和机械性能, 且优于浆态床中使用的微米级催化剂微胶囊. 相似文献
5.
Shufang Wang Huiling Li Kun Zhao Songqing Zhao Mingjing Chen Jingchun Chen Jianglong Wang Guangsheng Fu 《Applied Physics A: Materials Science & Processing》2011,105(2):407-410
A heterojunction was fabricated by growing a layer of Bi2Sr2Co2O
y
thin film on the 0.7 wt% Nb-doped SrTiO3 substrate. Such heterojunction showed good rectifying characteristics over a wide temperature range, and its transport mechanism
under the forward bias can be attributed to a space charge limited conduction mechanism via defects near the interface of
the heterojunction. Photovoltaic properties of the heterojunction were studied by using both continuous-wave and pulsed irradiations
and the results can be well explained by the photovoltaic effect of a p–n junction. 相似文献
6.
Lichang Yin Yunzuo Liu Jingbin Lu Guangyi Zhao Xianfeng Li Xiaoguang Wu Guangsheng Li Shuxian Wen Chunxiang Yang 《The European Physical Journal A - Hadrons and Nuclei》2001,11(4):379-383
High-spin states of 160Lu have been studied through the 144Sm( 19F, 3n) reaction. The previously known πh
11/2⊗υi
13/2 yrast band is extended from I
π = 21- to 25- and a four quasiparticle band with configuration πh
11/2[523]7/2 -⊗υh
9/2[521]3/2 -⊗ (υi
13/2)2 is reported.
Received: 21 May 2001 / Accepted: 19 July 2001 相似文献
7.
新三氮烯类试剂之一,2-羧基-4-溴苯基重氮氨基偶氮苯,在pH11.0的Na_2B_4O_7-NaOH缓冲介质中,有非离子表面活性剂TritonX-100及阴离子表面活性剂SDS的共同存在下,可与Ag(Ⅰ)生成稳定的2∶1红色配合物,红色配合物的λ_(max)=540nm,表观摩尔吸光系数ε_(540)=1.10×10 ̄5L·mol ̄(-1)·cm ̄(-1)。Ag量在0-10μg/25mL符合比尔定律。方法用于工业废水中痕量Ag的测定,结果满意。 相似文献
8.
Xu Ziyi Fu Taotao Zhu Chunying Jiang Shaokun Ma Youguang Wang Kai Luo Guangsheng 《Electrophoresis》2019,40(3):376-387
For revealing the dynamics of partially obstructed breakup of bubbles in microfluidic Y‐junctions, the combination of dimensionless power‐law and geometric model was applied to study the effects of capillary number, bubble length, and channel angle on the bubble rupture process. In the squeezing process, the gas‐liquid interface curve follows the parabolic model. For the evolution of the bubble neck during breakup, the increase of the bubble length, the channel angle, and the capillary number leads to the decrease of the focus distance α. The chord m increases with the increase of the capillary number and the decrease of the bubble length, and it would reach the maximum value when the channel angle is 90°. In the fast pinch‐off stage during bubble breakup, the bubble's neck curve no longer conforms to the parabolic model so the focus and chord no longer exist. For the evolution of the bubble head during breakup, the value of γ approaches 1 with the increase of the capillary number and the bubble length, and with the close of the channel angle to 90°. It is found that the quadrilateral model can be applied for the partially obstructed rupture of bubbles in the symmetrical microfluidic Y‐junction. 相似文献
9.
Qi Zhang Yunlong Shao Boye Li Yuanyuan Wu Jingying Dong Dongtang Zhang Yanan Wang Yong Yan Xiayan Wang Qiaosheng Pu Guangsheng Guo 《Chemical science》2021,12(11):4111
The analysis of single living cells, including intracellular delivery and extraction, is essential for monitoring their dynamic biochemical processes and exploring intracellular heterogeneity. However, owing to the 2D view in bright-field microscopy and optical distortions caused by the cell shape and the variation in the refractive index both inside and around the cells, achieving spatially undistorted imaging for high-precision manipulation within a cell is challenging. Here, an accurate and visual system is developed for single-cell spatial manipulation by correcting the aberration for simultaneous bright-field triple-view imaging. Stereo information from the triple view enables higher spatial resolution that facilitates the precise manipulation of single cells. In the bright field, we resolved the spatial locations of subcellular structures of a single cell suspended in a medium and measured the random spatial rotation angle of the cell with a precision of ±5°. Furthermore, we demonstrated the visual manipulation of a probe to an arbitrary spatial point of a cell with an accuracy of <1 pixel. This novel system is more accurate and less destructive for subcellular content extraction and drug delivery.We achieved the low-damage spatial puncture of single cells at specific visual points with an accuracy of <65 nm. 相似文献
10.