全文获取类型
收费全文 | 1614篇 |
免费 | 1篇 |
专业分类
化学工业 | 7篇 |
建筑科学 | 1篇 |
轻工业 | 4篇 |
一般工业技术 | 8篇 |
冶金工业 | 1592篇 |
自动化技术 | 3篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 48篇 |
1998年 | 484篇 |
1997年 | 266篇 |
1996年 | 201篇 |
1995年 | 94篇 |
1994年 | 78篇 |
1993年 | 98篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 43篇 |
1986年 | 24篇 |
1985年 | 28篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1978年 | 1篇 |
1977年 | 31篇 |
1976年 | 68篇 |
1955年 | 1篇 |
排序方式: 共有1615条查询结果,搜索用时 7 毫秒
71.
72.
73.
74.
75.
C Wu H Kobayashi B Sun TM Yoo CH Paik OA Gansow JA Carrasquillo I Pastan MW Brechbiel 《Canadian Metallurgical Quarterly》1997,5(10):1925-1934
Distinct differences in in vivo stability of the two diastereomeric C-Functionalized CyDTPA chelating agents, (CHX-A DTPA and CHX-B DTPA, both racemates), as recently reported prompted further investigation as to why differences in configuration produced striking effects on the in vivo stability of their yttrium complexes. To this end, the four individual component stereoisomers of CHX-A and CHX-B were synthesized and ability to bind yttrium was investigated both in vitro and in vivo. 相似文献
76.
77.
An expression cloning screen was used to isolate a novel gene homologous to the extracellular cysteine-rich domain of frizzled receptors. The gene (which we called sizzled for secreted frizzled) was shown to encode a soluble secreted protein, containing a functional signal sequence but no transmembrane domains. Sizzled (szl) is capable of inhibiting Xwnt8 as assayed by (1) dose-dependent inhibition of siamois induction by Xwnt8 in animal caps, (2) rescue of embryos ventralized by Xwnt8 DNA and (3) inhibition of XmyoD expression in the marginal zone. Szl can dorsalize Xenopus embryos if expressed after the midblastula transition, strengthening the idea that zygotic expression of wnts and in particular of Xwnt8 plays a role in antagonizing dorsal signals. It also suggests that inhibiting ventralizing wnts parallels the opposition of BMPs by noggin and chordin. szl expression is restricted to a narrow domain in the ventral marginal zone of gastrulating embryos. szl thus encodes a secreted antagonist of wnt signaling likely involved in inhibiting Xwnt8 and XmyoD ventrally and whose restricted expression represents a new element in the molecular pattern of the ventral marginal zone. 相似文献
78.
79.
80.