全文获取类型
收费全文 | 10020篇 |
免费 | 823篇 |
国内免费 | 1篇 |
出版年
2023年 | 40篇 |
2021年 | 69篇 |
2020年 | 86篇 |
2019年 | 75篇 |
2018年 | 180篇 |
2017年 | 219篇 |
2016年 | 235篇 |
2015年 | 228篇 |
2014年 | 272篇 |
2013年 | 436篇 |
2012年 | 752篇 |
2011年 | 832篇 |
2010年 | 428篇 |
2009年 | 260篇 |
2008年 | 619篇 |
2007年 | 683篇 |
2006年 | 603篇 |
2005年 | 526篇 |
2004年 | 492篇 |
2003年 | 491篇 |
2002年 | 454篇 |
2001年 | 310篇 |
2000年 | 332篇 |
1999年 | 164篇 |
1998年 | 102篇 |
1997年 | 84篇 |
1996年 | 102篇 |
1995年 | 78篇 |
1994年 | 87篇 |
1993年 | 83篇 |
1992年 | 80篇 |
1991年 | 83篇 |
1990年 | 77篇 |
1989年 | 70篇 |
1988年 | 74篇 |
1987年 | 53篇 |
1986年 | 71篇 |
1985年 | 77篇 |
1984年 | 75篇 |
1983年 | 75篇 |
1982年 | 79篇 |
1981年 | 70篇 |
1980年 | 69篇 |
1979年 | 80篇 |
1978年 | 54篇 |
1977年 | 62篇 |
1976年 | 54篇 |
1975年 | 32篇 |
1974年 | 41篇 |
1973年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
101.
102.
103.
104.
Serum activities of aspartate aminotransferase (AspAT = GOT), alanine aminotransferase (AlAT = GPT), and total lactate dehydrogenase (LDH) have been investigated in newborn calves, pigs, and lambs. In the two latter species the LDH isoenzyme distribution in serum was also studied. Blood samples were taken at frequent intervals from birth to 48–72 hrs. post partum. Calves and pigs were born with very low serum enzyme values, whereas lambs showed a picture more similar to what has been reported in human infants. In all species a marked temporary enzyme increase occurred during the first 24–48 hrs. This elevation was found not to be due to colostrum feeding, since a parallel increase was found in starved animals. Possible regulating mechanisms are discussed. The LDH isoenzyme pattern proved to be more stable than total LDH in the early post-natal period. The percentage isoenzyme distribution, however, showed characteristic differences from that found in adult animals of the same species. 相似文献
105.
Summary The isolation, morphology and growth chracteristics of pure cultures of a Thiothece, Lamprocystis and Thiodictyon strain are described.Their carotenoid composition is reported. The Thiothece strain produced in addition to okenone (1), several related ketocarotenoids, among which a demethylated okenone (6) was identified by a small scale total synthesis. Thiodictyon and Lamprocystis produced carotenoids of the rhodopinal (previously warmingone) series, the latter organism contained as major carotenoids a lycopenol (4), not previously found in Nature, and a cross-conjugated lycopenal (2), previously called anhydro-warmingone.Part 7. Acta chem. scand. 21, 2185 (1967). 相似文献
106.
107.
108.
109.
110.