全文获取类型
收费全文 | 7327篇 |
免费 | 329篇 |
国内免费 | 1篇 |
出版年
2023年 | 35篇 |
2022年 | 28篇 |
2021年 | 85篇 |
2020年 | 98篇 |
2019年 | 136篇 |
2018年 | 272篇 |
2017年 | 246篇 |
2016年 | 331篇 |
2015年 | 253篇 |
2014年 | 350篇 |
2013年 | 530篇 |
2012年 | 415篇 |
2011年 | 548篇 |
2010年 | 322篇 |
2009年 | 223篇 |
2008年 | 389篇 |
2007年 | 433篇 |
2006年 | 466篇 |
2005年 | 409篇 |
2004年 | 338篇 |
2003年 | 380篇 |
2002年 | 297篇 |
2001年 | 188篇 |
2000年 | 162篇 |
1999年 | 110篇 |
1998年 | 63篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 22篇 |
1994年 | 19篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 20篇 |
1990年 | 14篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 26篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 18篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1953年 | 18篇 |
1952年 | 40篇 |
1888年 | 14篇 |
1887年 | 14篇 |
1883年 | 9篇 |
排序方式: 共有7657条查询结果,搜索用时 31 毫秒
1.
2.
Judyta Kruk Irena Baranowska Bogusaw Buszewski Sylwia Bajkacz Bartosz Kowalski Magdalena Ligor 《Chirality》2019,31(2):138-149
Plant material is a rich source of valuable compounds such as flavanones. Their different forms influence bioavailability and biological activity, causing problems with the selection of plant material for specific purposes. The purpose of this research was to determine selected flavanone (eriodictyol, naringenin, liquiritigenin, and hesperetin) enantiomer contents in free form and bonded to glycosides by an RP‐UHPLC‐ESI‐MS/MS method. Different parts (stems, leaves, and flowers) of goldenrod (Solidago virgaurea L.), lucerne (Medicago sativa L.), and phacelia (Phacelia tanacetifolia Benth.) were used. The highest content of eriodictyol was found in goldenrod flowers (13.1 μg/g), where it occurred mainly as the (S)‐enantiomer, and the greatest proportion of the total amount was bonded to glycosides. The richest source of naringenin was found to be lucerne leaves (4.7 μg/g), where it was mainly bonded to glycosides and with the (S)‐enantiomer as the dominant form. Liquiritigenin was determined only in lucerne, where the flowers contained the highest amount (1.2 μg/g), with the (R)‐enantiomer as dominant aglycone form and the (S)‐enantiomer as the dominant glycosylated form. The highest hesperetin content was determined in phacelia leaves (0.38 μg/g), where it was present in the form of a glycoside and only as the (S)‐enantiomer. A comparison of the different analyte forms occurring in different plant parts was performed for the first time. 相似文献
3.
4.
Agnieszka Fischer Danuta Wiechuła Lidia Postek-Stefańska Jerzy Kwapuliński 《Biological trace element research》2009,132(1-3):19-26
The study shows the results of research on the concentrations of metals (Cd, Pb, Mn, Cu, Cr, Fe, Zn, Na, K, Mg, and Ca) in deciduous and permanent teeth with respect to their location in the oral cavity (maxilla, mandible). It has been found that the concentrations of metals were significantly higher in the deciduous teeth than in permanent ones. Regression analysis and principal component analysis revealed an increased dynamics of the processes of binding the elements by the hydroxyapatite of deciduous teeth. Higher concentrations of the metals were found in the maxilla permanent and deciduous teeth than in the mandible ones. 相似文献
5.
6.
7.
S Kardaszewicz K Rozak-Lesiak Z Rusinowska A Grzesiak 《Folia haematologica (Leipzig, Germany : 1928)》1985,112(6):957-963
Results of treatment obtained in 273 patients with HD from 1971 to 1980 were compared with 240 patients with HD in the period from 1951 to 1970. All patients in our material were analysed by taking into consideration the histological type and the clinical stage. We confirmed the prolongation of the survival time in the patients with HD in last ten years to 18 months. The introduction of polychemotherapy contributed to this observation. 相似文献
8.
9.
Julius Głowacki 《Plant Systematics and Evolution》1909,59(2):51-53
Ohne Zusammenfassung 相似文献
10.