全文获取类型
收费全文 | 242937篇 |
免费 | 5679篇 |
国内免费 | 643篇 |
学科分类
工业技术 | 249259篇 |
出版年
2021年 | 2622篇 |
2020年 | 2072篇 |
2019年 | 2539篇 |
2018年 | 4397篇 |
2017年 | 4427篇 |
2016年 | 4635篇 |
2015年 | 3297篇 |
2014年 | 4852篇 |
2013年 | 12629篇 |
2012年 | 7588篇 |
2011年 | 9511篇 |
2010年 | 7690篇 |
2009年 | 8191篇 |
2008年 | 8371篇 |
2007年 | 8369篇 |
2006年 | 6838篇 |
2005年 | 6250篇 |
2004年 | 5946篇 |
2003年 | 5770篇 |
2002年 | 5403篇 |
2001年 | 5322篇 |
2000年 | 5171篇 |
1999年 | 5296篇 |
1998年 | 13629篇 |
1997年 | 9718篇 |
1996年 | 7461篇 |
1995年 | 5357篇 |
1994年 | 4803篇 |
1993年 | 4658篇 |
1992年 | 3448篇 |
1991年 | 3292篇 |
1990年 | 3051篇 |
1989年 | 3109篇 |
1988年 | 2995篇 |
1987年 | 2543篇 |
1986年 | 2437篇 |
1985年 | 2930篇 |
1984年 | 2711篇 |
1983年 | 2468篇 |
1982年 | 2246篇 |
1981年 | 2412篇 |
1980年 | 2216篇 |
1979年 | 2231篇 |
1978年 | 2228篇 |
1977年 | 2648篇 |
1976年 | 3795篇 |
1975年 | 1934篇 |
1974年 | 1831篇 |
1973年 | 1869篇 |
1972年 | 1481篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
1.
2.
3.
4.
5.
Leibetseder Andreas Schoeffmann Klaus Keckstein Jörg Keckstein Simon 《Multimedia Tools and Applications》2022,81(5):6191-6215
Multimedia Tools and Applications - Endometriosis is a common gynecologic condition typically treated via laparoscopic surgery. Its visual versatility makes it hard to identify for non-specialized... 相似文献
6.
7.
Journal of Chemical Ecology - Biocontrol agents such as parasitic wasps use long-range volatiles and host-associated cues from lower trophic levels to find their hosts. However, this chemical... 相似文献
8.
Moghadam Seyedeh Hadis Ashofteh Parisa-Sadat Loáiciga Hugo A. 《Water Resources Management》2022,36(9):3181-3205
Water Resources Management - The water evaluation and planning (WEAP) approach and the invasive weed optimization algorithm (IWOA) are herein employed to determine the optimal operating policies in... 相似文献
9.
Photoresponsive biomaterials are experiencing a transition from in vitro models to in vivo demonstrations that point toward clinical translation. Dynamic hydrogels for cell encapsulation, light-responsive carriers for controlled drug delivery, and nanomaterials containing photosensitizers for photodynamic therapy are relevant examples. Nonetheless, the step to the clinic largely depends on their combination with technologies to bring light into the body. This review highlights the challenge of photoactivation in vivo, and presents strategies for light management that can be adopted for this purpose. The authors’ focus is on technologies that are materials-driven, particularly upconversion nanoparticles that assist in “direct path” light delivery through tissue, and optical waveguides that “clear the path” between external light source and in vivo target. The authors’ intention is to assist the photoresponsive biomaterials community transition toward medical technologies by presenting light delivery concepts that can be integrated with the photoresponsive targets. The authors also aim to stimulate further innovation in materials-based light delivery platforms by highlighting needs and opportunities for in vivo photoactivation of biomaterials. 相似文献
10.
Prof. Andrea Baier Dr. Anne Kokel Dr. William Horton Ewa Gizińska Dr. Garima Pandey Prof. Ryszard Szyszka Prof. Béla Török Prof. Marianna Török 《ChemMedChem》2021,16(12):1927-1932
A set of novel hydrazone derivatives were synthesized and analyzed for their biological activities. The compounds were tested for their inhibitory effect on the phosphorylating activity of the protein kinase CK2, and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the DPPH, ABTS and peroxyl radicals. Several compounds have been identified as good antioxidants as well as potent protein kinase CK2 inhibitors. Most hydrazones containing a 4-N(CH3)2 residue or perfluorinated phenyl rings showed high activity in the radical-scavenging assays and possess nanomolar IC50 values in the kinase assays. 相似文献