全文获取类型
收费全文 | 6838篇 |
免费 | 623篇 |
国内免费 | 3篇 |
专业分类
7464篇 |
出版年
2023年 | 44篇 |
2022年 | 120篇 |
2021年 | 236篇 |
2020年 | 101篇 |
2019年 | 134篇 |
2018年 | 153篇 |
2017年 | 108篇 |
2016年 | 220篇 |
2015年 | 383篇 |
2014年 | 354篇 |
2013年 | 428篇 |
2012年 | 598篇 |
2011年 | 546篇 |
2010年 | 353篇 |
2009年 | 276篇 |
2008年 | 385篇 |
2007年 | 407篇 |
2006年 | 347篇 |
2005年 | 322篇 |
2004年 | 331篇 |
2003年 | 267篇 |
2002年 | 247篇 |
2001年 | 74篇 |
2000年 | 59篇 |
1999年 | 64篇 |
1998年 | 71篇 |
1997年 | 41篇 |
1996年 | 33篇 |
1995年 | 25篇 |
1994年 | 41篇 |
1993年 | 41篇 |
1992年 | 46篇 |
1991年 | 45篇 |
1990年 | 30篇 |
1989年 | 38篇 |
1988年 | 20篇 |
1987年 | 23篇 |
1986年 | 22篇 |
1985年 | 26篇 |
1984年 | 28篇 |
1983年 | 29篇 |
1982年 | 23篇 |
1981年 | 16篇 |
1980年 | 24篇 |
1979年 | 27篇 |
1978年 | 28篇 |
1977年 | 19篇 |
1976年 | 18篇 |
1974年 | 19篇 |
1971年 | 20篇 |
排序方式: 共有7464条查询结果,搜索用时 0 毫秒
961.
962.
963.
Epoxy derivatives of aromatic polycyclic hydrocarbons. The preparation of benz[a]anthracene 8,9-oxide and 10,11-dihydrobenz[a]anthracene 8,9-oxide and their metabolism by rat liver preparations 下载免费PDF全文
P. Sims 《The Biochemical journal》1971,125(1):159-168
The syntheses of 10,11-dihydrobenz[a]anthracene 8,9-oxide, benz[a]anthracene 8,9-oxide and 9-hydroxybenz[a]anthracene are described, together with those of a number of related compounds. The epoxides react both chemically and enzymically with water to yield the corresponding dihydrodiols and with reduced glutathione to form glutathione conjugates, and they react chemically with N-acetylcysteine to yield the corresponding mercapturic acids. 8,9-Dihydro-8,9-dihydroxybenz[a]anthracene, formed enzymically from benz[a]anthracene 8,9-oxide, was identical with a dihydrodiol formed when benz[a]anthracene was metabolized by rat liver homogenates. Similarly 10,11-dihydrobenz[a]anthracene 8,9-oxide yielded a dihydrodiol identical with the product formed when 10,11-dihydrobenz[a]anthracene was metabolized. 相似文献
964.
965.
966.
Vernon I. Cheadle Ernest M. Gifford Jr. Katherine Esau 《Biotechnic & histochemistry》1953,28(2):49-53
A technic is described for producing critically stained preparations of phloem tissue. The preparations promise to be relatively stable. Sections of fixed unembedded or of embedded (paraffin or celloidin) phloem, cambium, and xylem are (1) stained in Foster's tannic acid-ferric chloride combination; (2) treated with 1% NaHCOg in 25% or 50% ethyl alcohol for 30 minutes; (3) stained in a saturated solution of lacmoid (made alkaline by adding a few ml. of 1% NaHCO3 in 25% alcohol) for 12 to 18 hours; (4) dehydrated and cleared in a series composed of 1% solution of NaHCOs in 50% ethyl alcohol, 80%, 95%, and absolute alcohol, equal proportions of absolute alcohol, clove oil, and xylene, and finally pure xylene; and (5) mounted in a neutral resin. Callose and lignified secondary walls are blue or blue-green in color, cellulose walls and stainable protoplasmic contents are generally light brown. The technic has been successful with sections from 5 to 40μ in thickness, and the staining has been satisfactory for both color and black and white photomicrography. 相似文献
967.
F.-Nora Vögtle Björn Brändl Austin Larson Manuela Pendziwiat Marisa W. Friederich Susan M. White Alice Basinger Cansu Kücükköse Hiltrud Muhle Johanna A. Jähn Oliver Keminer Katherine L. Helbig Carolyn F. Delto Lisa Myketin Dirk Mossmann Nils Burger Noriko Miyake Audrey Burnett Ingo Helbig 《American journal of human genetics》2018,102(4):557-573
968.
969.
970.