全文获取类型
收费全文 | 1082篇 |
免费 | 49篇 |
国内免费 | 8篇 |
专业分类
化学 | 752篇 |
晶体学 | 15篇 |
力学 | 34篇 |
数学 | 137篇 |
物理学 | 201篇 |
出版年
2023年 | 9篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 24篇 |
2019年 | 21篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 43篇 |
2015年 | 39篇 |
2014年 | 40篇 |
2013年 | 79篇 |
2012年 | 77篇 |
2011年 | 112篇 |
2010年 | 69篇 |
2009年 | 57篇 |
2008年 | 85篇 |
2007年 | 52篇 |
2006年 | 59篇 |
2005年 | 80篇 |
2004年 | 69篇 |
2003年 | 54篇 |
2002年 | 36篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1981年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1139条查询结果,搜索用时 15 毫秒
1.
Ji Yong Bae Dae‐Woong Jung Chan Bae Jeong Hong‐Seung Kim Jung Dae Kim Hyun‐Joo Ro Sangmi Jun Dong Uk Kim Jun Min Kim Gi‐Ra Yi Gaehang Lee Ki Soo Chang 《Particle & Particle Systems Characterization》2019,36(7)
The plasmonic photothermal (PPT) characteristics of gold nanostructures have been extensively investigated theoretically and experimentally due to their potential for use materials science and industry. The management of the size and shape of gold nanoparticles has been a key issue in the development of better solutions for PPT heat generation because their size and shape determine their resultant photothermal properties. However, the light absorption of gold nanostructures is mainly dependent on the wavelength and orientation of the incident light; hence, maintaining uniform size and shape is critical for achieving maximum photothermal energy. Morphologically homogeneous spherical gold nanoparticles, or super gold nanospheres prepared by slowly etching uniform octahedral gold nanoparticles, demonstrate better PPT heat generation compared with commercially available nonsmooth gold nanoparticles (GNSs). The PPT heating experiments show a maximum temperature difference of 5.7 °C between the super and ordinary GNSs with the same average maximum Feret's diameters, which result from the more efficient PPT heat power generation (20.6%) of the super GNSs. In an electromagnetic‐wave simulation, the super GNSs show lower polarization dependence and a 24.6% higher absorption cross‐section than ordinary GNSs. 相似文献
2.
3.
LeRoy B. Beasley Young Bae Jun Seok-Zun Song 《Czechoslovak Mathematical Journal》2018,68(4):1055-1066
Let ?+ be the semiring of all nonnegative integers and A an m × n matrix over ?+. The rank of A is the smallest k such that A can be factored as an m × k matrix times a k×n matrix. The isolation number of A is the maximum number of nonzero entries in A such that no two are in any row or any column, and no two are in a 2 × 2 submatrix of all nonzero entries. We have that the isolation number of A is a lower bound of the rank of A. For A with isolation number k, we investigate the possible values of the rank of A and the Boolean rank of the support of A. So we obtain that the isolation number and the Boolean rank of the support of a given matrix are the same if and only if the isolation number is 1 or 2 only. We also determine a special type of m×n matrices whose isolation number is m. That is, those matrices are permutationally equivalent to a matrix A whose support contains a submatrix of a sum of the identity matrix and a tournament matrix. 相似文献
4.
Shiv Poojan Seung-Hyun Bae Jae-Woong Min Eun Young Lee Yura Song Hee Yeon Kim Hye Won Sim Eun-Kyung Kang Young-Ho Kim Hae-Ock Lee Yourae Hong Woong-Yang Park Hyonchol Jang Kyeong-Man Hong 《Experimental & molecular medicine》2020,52(7):1102
To elucidate the epigenetic mechanisms of drug resistance, epigenetically reprogrammed H460 cancer cells (R-H460) were established by the transient introduction of reprogramming factors. Then, the R-H460 cells were induced to differentiate by the withdrawal of stem cell media for various durations, which resulted in differentiated R-H460 cells (dR-H460). Notably, dR-H460 cells differentiated for 13 days (13dR-H460 cells) formed a significantly greater number of colonies showing drug resistance to both cisplatin and paclitaxel, whereas the dR-H460 cells differentiated for 40 days (40dR-H460 cells) lost drug resistance; this suggests that 13dR-cancer cells present short-term resistance (less than a month). Similarly, increased drug resistance to both cisplatin and paclitaxel was observed in another R-cancer cell model prepared from N87 cells. The resistant phenotype of the cisplatin-resistant (CR) colonies obtained through cisplatin treatment was maintained for 2–3 months after drug treatment, suggesting that drug treatment transforms cells with short-term resistance into cells with medium-term resistance. In single-cell analyses, heterogeneity was not found to increase in 13dR-H460 cells, suggesting that cancer cells with short-term resistance, rather than heterogeneous cells, may confer epigenetically driven drug resistance in our reprogrammed cancer model. The epigenetically driven short-term and medium-term drug resistance mechanisms could provide new cancer-fighting strategies involving the control of cancer cells during epigenetic transition.Subject terms: Tumour heterogeneity, Epigenetics 相似文献
5.
6.
Daewha Hong KiEun Bae Dr. Duckshin Park Houngkyung Kim Seok‐Pyo Hong Mi‐Hee Kim Dr. Bong Soo Lee Dr. Sangwon Ko Prof. Dr. Seokwoo Jeon Xu Zheng Prof. Dr. Wan Soo Yun Prof. Dr. Yang‐Gyun Kim Prof. Dr. Insung S. Choi Prof. Dr. Jungkyu K. Lee 《化学:亚洲杂志》2015,10(3):568-571
Direct patterning of streptavidin and NIH 3T3 fibroblast cells was successfully achieved over a large‐area pristine graphene sheet on Si/SiO2 by aryl azide‐based photografting with the conventional UV lithographic technique and surface‐initiated, atom transfer radical polymerization of oligo(ethylene glycol) methacrylate. 相似文献
7.
8.
Yong Weon Yi Hyo Jin Kang Edward Jeong Bae Seunghoon Oh Yeon-Sun Seong Insoo Bae 《Experimental & molecular medicine》2015,47(2):e143
An F-box protein, β-TrCP recognizes substrate proteins and destabilizes them through ubiquitin-dependent proteolysis. It regulates the stability of diverse proteins and functions as either a tumor suppressor or an oncogene. Although the regulation by β-TrCP has been widely studied, the regulation of β-TrCP itself is not well understood yet. In this study, we found that the level of β-TrCP1 is downregulated by various protein kinase inhibitors in triple-negative breast cancer (TNBC) cells. A PI3K/mTOR inhibitor PI-103 reduced the level of β-TrCP1 in a wide range of TNBC cells in a proteasome-dependent manner. Concomitantly, the levels of c-Myc and cyclin E were also downregulated by PI-103. PI-103 reduced the phosphorylation of β-TrCP1 prior to its degradation. In addition, knockdown of β-TrCP1 inhibited the proliferation of TNBC cells. We further identified that pharmacological inhibition of mTORC2 was sufficient to reduce the β-TrCP1 and c-Myc levels. These results suggest that mTORC2 regulates the stability of β-TrCP1 in TNBC cells and targeting β-TrCP1 is a potential approach to treat human TNBC. 相似文献
9.
Hyewon Ryoo Hyung Bin Bae Dr. Young‐Min Kim Dr. Jin‐Gyu Kim Dr. Seongsu Lee Prof. Sung‐Yoon Chung 《Angewandte Chemie (International ed. in English)》2015,54(27):7963-7967
Using spinel‐type Li(Mn1.5Ni0.5)O4 with two different cations, Mn and Ni, in the oxygen octahedra as a model system, we show that a cation ordering transition takes place through the formation of Frenkel‐type point defects. A series of experimental results based on atomic‐scale observations and in situ powder diffractions along with ab initio calculations consistently support such defect‐mediated transition behavior. In addition to providing a precise suggestion of the intermediate transient states and the resulting kinetic pathway during the transition between two phases, our findings emphasize the significant role of point defects in ordering transformation of complex oxides. 相似文献
10.
Jinhwang Kim Hyeon-Min Cha Mikyung Park Dileep K. Singh Gi H. Bae Seong H. Kim Ikyon Kim 《Journal of heterocyclic chemistry》2020,57(9):3279-3293
A new chemical space was generated via C2-functionalization of 3-arylbenzofurans. Mannich reaction of 3-arylbenzofurans with secondary amines and formaldehyde allowed for installation of aminomethyl unit at C2 position of benzofurans. A formyl group at C2 site introduced as a result of Vilsmeier-Haack formylation of 3-arylbenzofurans was employed as a reacting partner for three-component Kabachnik-Fields reaction with various amines and triethyl phosphite to give a wide variety of aminomethylphosphonates. Furthermore, several benzo[d]oxazoles and pyrrolo[1,2-a]quinoxalines were prepared by using the formyl group. Biological screening of the synthesized compounds revealed that the benzofuran bearing a pyrrolo[1,2-a]quinoxaline moiety ( 5b ) most potently inhibited the viability of human blood cancer cells, but not solid tumor cells. Caspase activity assay, analysis of Annexin V-positive cells, and Western blot analysis indicated that 5b -induced death of human lymphoma U937 cells could result from its potential to induce the caspase-dependent apoptotic death of blood cancer cells with inhibition of ERK activation. 相似文献