全文获取类型
收费全文 | 24194篇 |
免费 | 1719篇 |
国内免费 | 9篇 |
出版年
2023年 | 113篇 |
2022年 | 263篇 |
2021年 | 609篇 |
2020年 | 367篇 |
2019年 | 488篇 |
2018年 | 618篇 |
2017年 | 510篇 |
2016年 | 860篇 |
2015年 | 1279篇 |
2014年 | 1433篇 |
2013年 | 1782篇 |
2012年 | 2051篇 |
2011年 | 1991篇 |
2010年 | 1255篇 |
2009年 | 1083篇 |
2008年 | 1482篇 |
2007年 | 1402篇 |
2006年 | 1286篇 |
2005年 | 1171篇 |
2004年 | 1068篇 |
2003年 | 992篇 |
2002年 | 829篇 |
2001年 | 203篇 |
2000年 | 199篇 |
1999年 | 222篇 |
1998年 | 157篇 |
1997年 | 151篇 |
1996年 | 110篇 |
1995年 | 116篇 |
1994年 | 126篇 |
1993年 | 108篇 |
1992年 | 110篇 |
1991年 | 106篇 |
1990年 | 126篇 |
1989年 | 102篇 |
1988年 | 101篇 |
1987年 | 85篇 |
1986年 | 84篇 |
1985年 | 85篇 |
1984年 | 61篇 |
1983年 | 64篇 |
1982年 | 57篇 |
1981年 | 57篇 |
1980年 | 39篇 |
1979年 | 63篇 |
1978年 | 57篇 |
1977年 | 44篇 |
1976年 | 38篇 |
1975年 | 41篇 |
1974年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Sebastián Moran Miguel Vizoso Anna Martinez-Cardús Antonio Gomez Xavier Matías-Guiu Sebastián M Chiavenna Andrés G Fernandez Manel Esteller 《Epigenetics》2014,9(6):829-833
A formalin-fixed paraffin-embedded (FFPE) sample usually yields highly degraded DNA, which limits the use of techniques requiring high-quality DNA, such as Infinium Methylation microarrays. To overcome this restriction, we have applied an FFPE restoration procedure consisting of DNA repair and ligation processes in a set of paired fresh-frozen (FF) and FFPE samples. We validated the FFPE results in comparison with matched FF samples, enabling us to use FFPE samples on the Infinium HumanMethylation450 Methylation array. 相似文献
2.
Silk fibroin with the alanyl carboxyl carbon enriched with 13C was obtained by giving a diet containing 13C-enriched alanine to the larvae of Bombyx mori and Antheraea pernyi at the fifth instar. Sericin-free fibroin fibers were prepared from cocoons, and gut was made from the liquid silk in the gland. The final 13C content was about 13%. Cross polarization/magic angle sample spinning spectra at 25 MHz and 75 MHz were measured for each sample at different orientations. Spectra were simulated using the principal values and orientations of the shielding tensor in the alanine crystal. The results indicate that the beta-structure of the fibroin may be a little more flattened than the typical pleated sheet beta-structure. 相似文献
3.
4.
When rats received glucagon or insulin every 2 h after partial hepatectomy (Hx), hepatic putrescine content was increased above control levels at 6 and 12 h, respectively. When the two hormones were combined, the increased levels were additive. Hepatic ornithine decarboxylase activity was above control levels at 12 h after insulin treatment. Hepatic spermidine N1-acetyltransferase activity was enhanced at 6 h only when glucagon was dosed. Putrescine administration from 0 to 4 h or from 6 to 10 h increased hepatic DNA synthesis to similar levels 22 h after Hx. These results suggest that glucagon and insulin additively stimulate hepatic putrescine production after Hx. This may explain the cooperative stimulation of liver regeneration by both hormones. 相似文献
5.
6.
7.
Anna Morcom 《The journal of the Royal Anthropological Institute》2014,20(4):788-789
8.
9.
10.