全文获取类型
收费全文 | 5799篇 |
免费 | 347篇 |
国内免费 | 1篇 |
出版年
2021年 | 66篇 |
2020年 | 27篇 |
2019年 | 41篇 |
2018年 | 59篇 |
2017年 | 59篇 |
2016年 | 84篇 |
2015年 | 127篇 |
2014年 | 202篇 |
2013年 | 263篇 |
2012年 | 263篇 |
2011年 | 294篇 |
2010年 | 150篇 |
2009年 | 142篇 |
2008年 | 255篇 |
2007年 | 261篇 |
2006年 | 253篇 |
2005年 | 281篇 |
2004年 | 232篇 |
2003年 | 240篇 |
2002年 | 265篇 |
2001年 | 234篇 |
2000年 | 248篇 |
1999年 | 180篇 |
1998年 | 97篇 |
1997年 | 58篇 |
1996年 | 51篇 |
1995年 | 55篇 |
1994年 | 54篇 |
1993年 | 52篇 |
1992年 | 122篇 |
1991年 | 136篇 |
1990年 | 105篇 |
1989年 | 106篇 |
1988年 | 122篇 |
1987年 | 99篇 |
1986年 | 91篇 |
1985年 | 85篇 |
1984年 | 60篇 |
1983年 | 63篇 |
1982年 | 45篇 |
1980年 | 35篇 |
1979年 | 49篇 |
1978年 | 43篇 |
1977年 | 27篇 |
1976年 | 30篇 |
1975年 | 35篇 |
1974年 | 31篇 |
1973年 | 35篇 |
1971年 | 34篇 |
1970年 | 29篇 |
排序方式: 共有6147条查询结果,搜索用时 125 毫秒
101.
The effects of photoperiod on the sex expression of cucumberflowers were examined in relation to the endogenous GA and ethyleneproduction with short day (SD)- and long day (LD)-sensitivecultivars under controlled environmental conditions. Growth of plants was greatly reduced under LD in both typesof cultivars. Reflecting this, GA activity was greater and ethyleneevolution less in plants grown under SD than in those underLD. However, the number of pistillate flowers increased underSD and LD in SD- and LD-sensitive cultivar, respectively, indicatingthat a change in sex expression did not coincide with hormonalchanges in the SD-sensitive cultivar. Thus, the effect of photoperiodon the sex expression was found to be separate, at least inpart, from the effect of GA or ethylene in cucumber. (Received September 16, 1982; Accepted December 7, 1982) 相似文献
102.
103.
Quantitative isolation of total glycosphingolipids from animal cells 总被引:49,自引:0,他引:49
The quantitative isolation of total glycosphingolipids from crude lipid extracts without contamination from other lipid classes is described. The method consists of (a) acetylation of total lipids with pyridine and acetic anhydride, (b) separation of acetylated glycolipids from nonglycolipids on a magnesia-silica gel (Florisil) column, and (c) deacetylation of glycolipid in chloroform-methanol-sodium methoxide. This method is useful for determination of microgram quantities of glycolipids derived from less than 1 ml of packed cells. 相似文献
104.
105.
Possible site of flavonoid synthesis in the photosynthetic apparatus (Short Communication) 下载免费PDF全文
Koshi Saito 《The Biochemical journal》1974,144(2):431-432
Chloroplasts were prepared in aqueous suspension from buckwheat (Fagopyrum esculentum Moench.) seedlings, and the incorporation of [1-(14)C]acetic acid into quercetin (3,5,7,3',4'-pentahydroxyflavone) by the isolated chloroplast preparations was investigated. 相似文献
106.
107.
Comparison of the Pathogenicity for Mice of Mycobacterium fortuitum and Mycobacterium abscessus 总被引:3,自引:0,他引:3 下载免费PDF全文
The pathogenicity for mice of 12 strains of Mycobacterium abscessus was compared with that for 8 strains of M. fortuitum. Both species caused lesions in kidneys and produced "spinning disease" resulting from inner ear infections. No major differences in pathogenicity of these two species were demonstrated. Strain to strain variation was marked, especially with M. abscessus. For example, 1.6 x 10(6) organisms of strain 11188 of M. abscessus produced death in four of five animals within 42 days, whereas strain 380 of M. abscessus failed to produce any deaths within 42 days. In the case of M. fortuitum, the greatest mortality observed was one of five animals, yet the incidence of spinning disease and kidney disease occurred earlier postinfection than in mice infected with M. abscessus. Histologically, abscess formation by a strain of M. abscessus was greater than by a strain of M. fortuitum, but this difference cannot be interpreted as a species difference. 相似文献
108.
109.
110.