全文获取类型
收费全文 | 60431篇 |
免费 | 10046篇 |
国内免费 | 1556篇 |
专业分类
化学 | 57059篇 |
晶体学 | 583篇 |
力学 | 1399篇 |
综合类 | 1篇 |
数学 | 4213篇 |
物理学 | 8778篇 |
出版年
2023年 | 170篇 |
2022年 | 446篇 |
2021年 | 664篇 |
2020年 | 1635篇 |
2019年 | 2925篇 |
2018年 | 1312篇 |
2017年 | 946篇 |
2016年 | 3914篇 |
2015年 | 3975篇 |
2014年 | 4043篇 |
2013年 | 5371篇 |
2012年 | 4773篇 |
2011年 | 4189篇 |
2010年 | 3970篇 |
2009年 | 3798篇 |
2008年 | 3994篇 |
2007年 | 3281篇 |
2006年 | 2907篇 |
2005年 | 2962篇 |
2004年 | 2616篇 |
2003年 | 2241篇 |
2002年 | 2847篇 |
2001年 | 1984篇 |
2000年 | 1793篇 |
1999年 | 680篇 |
1998年 | 300篇 |
1997年 | 323篇 |
1996年 | 355篇 |
1995年 | 274篇 |
1994年 | 289篇 |
1993年 | 289篇 |
1992年 | 281篇 |
1991年 | 211篇 |
1990年 | 165篇 |
1989年 | 149篇 |
1988年 | 145篇 |
1987年 | 125篇 |
1986年 | 106篇 |
1985年 | 174篇 |
1984年 | 113篇 |
1983年 | 105篇 |
1982年 | 125篇 |
1981年 | 94篇 |
1980年 | 81篇 |
1978年 | 85篇 |
1977年 | 89篇 |
1976年 | 99篇 |
1975年 | 103篇 |
1974年 | 83篇 |
1973年 | 107篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Asner DM Athanas M Bliss DW Brower WS Masek G Paar HP Gronberg J Korte CM Kutschke R Menary S Morrison RJ Nakanishi S Nelson HN Nelson TK Qiao C Richman JD Roberts D Ryd A Tajima H Witherell MS Balest R Cho K Ford WT Lohner M Park H Rankin P Smith JG Alexander JP Bebek C Berger BE Berkelman K Bloom K Browder TE Cassel DG Cho HA Coffman DM Crowcroft DS Dickson M Drell PS Dumas DJ Ehrlich R Elia R Gaidarev P Garcia-Sciveres M Gittelman B Gray SW Hartill DL Heltsley BK Henderson S Jones CD 《Physical review D: Particles and fields》1996,53(3):1039-1050
993.
994.
995.
996.
Imazethapyr is the herbicide developed for use in leguminous crops. In this study, flow-injection liposome immunoanalysis (FILIA) has been shown to be capable of measuring imazethapyr in a buffered solution with a detection limit of 0.1 ppb through the optimization process. Protein A coated glass beads covalently conjugated with antibody were contained in a glass column, and this column was used as an immunoreactor. Liposomes which encapsulated a fluorescent dye, sulforhodamine B (SRB) or carboxyfluorescein (CF), generated the analytical signal. By loading larger volumes of sample onto the column, it was shown that the detection limit could be lowered. Liposomes containing carboxyfluorescein gave more sensitive response and a lower detection limit than those with sulforhodamine B. Also, improved response was obtained by using a smaller flow cell in the fluorescence detector due to the reduced dilution effect. 相似文献
997.
Summary Polyethylene oxide (PEO)-based polymers with hydroxy, methoxy, and aminopropoxy terminal groups were coated on diol functionalized and hexamethyldisilazane end-capped silica particles. Proton-donor and proton-acceptor test solutes, including carboxylic acids, hydroxy-containing compounds, arylamines, and alkylamines were used to evaluate the chromatographic performances of these polymer coated particles under SFC conditions with neat CO2 as mobile phase. It was found that the particles coated with hydroxy-terminated PEO were suitable for the separation of proton-donor compounds such as hydroxy-containing compounds and carboxylic acids, and the particles coated with aminopropoxy-terminated PEO could be used for the separation of amines. That is, the proton-accepting stationary phase is suitable for the separation of proton accepting solutes, including strong basic alkylamines (pKb4), using neat CO2 as mobile phase, while the protondonating stationary phase is suitable for the separation of proton-donating compounds such as carboxylic acids (pKa4). Hydrogen bond basicity was found to be a critical factor for the chromatography of basic amines. Low volatility acidic and basic drugs were chromatographed using the new stationary phases. The stability of the PEO coated particles was determined by measuring the loss of organic carbon under SFC conditions. It was found that approximately 18 % of the coating (average molecular weight of 15,000) was washed out of the particles by supercritical CO2 after 7 h at 350 atm and 50°C 相似文献
998.
999.
1000.