全文获取类型
收费全文 | 10315篇 |
免费 | 794篇 |
专业分类
11109篇 |
出版年
2021年 | 98篇 |
2020年 | 49篇 |
2019年 | 85篇 |
2018年 | 103篇 |
2017年 | 123篇 |
2016年 | 157篇 |
2015年 | 252篇 |
2014年 | 334篇 |
2013年 | 552篇 |
2012年 | 440篇 |
2011年 | 471篇 |
2010年 | 306篇 |
2009年 | 288篇 |
2008年 | 476篇 |
2007年 | 496篇 |
2006年 | 448篇 |
2005年 | 499篇 |
2004年 | 489篇 |
2003年 | 484篇 |
2002年 | 394篇 |
2001年 | 385篇 |
2000年 | 403篇 |
1999年 | 344篇 |
1998年 | 116篇 |
1997年 | 138篇 |
1996年 | 111篇 |
1995年 | 126篇 |
1994年 | 100篇 |
1993年 | 106篇 |
1992年 | 240篇 |
1991年 | 228篇 |
1990年 | 241篇 |
1989年 | 198篇 |
1988年 | 189篇 |
1987年 | 175篇 |
1986年 | 153篇 |
1985年 | 150篇 |
1984年 | 124篇 |
1983年 | 106篇 |
1982年 | 86篇 |
1981年 | 71篇 |
1980年 | 57篇 |
1979年 | 85篇 |
1978年 | 84篇 |
1977年 | 68篇 |
1976年 | 47篇 |
1975年 | 42篇 |
1974年 | 50篇 |
1973年 | 43篇 |
1972年 | 49篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Flavonoids: potent inhibitors of arachidonate 5-lipoxygenase 总被引:2,自引:0,他引:2
T Yoshimoto M Furukawa S Yamamoto T Horie S Watanabe-Kohno 《Biochemical and biophysical research communications》1983,116(2):612-618
Various flavonoids were found to be relatively selective inhibitors of arachidonate 5-lipoxygenase which initiates the biosynthesis of leukotrienes with the activity of slow reacting substance of anaphylaxis. Cirsiliol (3',4',5-trihydroxy-6,7-dimethoxyflavone) was most potent, and the enzyme partially purified from rat basophilic leukemia cells was inhibited by 97% at a concentration of 10 microM (IC50, about 0.1 microM). 12-Lipoxygenases from bovine platelets and porcine leukocytes were also inhibited but at higher concentrations (IC50, about 1 microM), and fatty acid cyclooxygenase purified from bovine vesicular gland was scarcely affected. The compound at 10 microM suppressed by 99% the immunological release of slow reacting substance of anaphylaxis from passively sensitized guinea pig lung (IC50, about 0.4 microM). 相似文献
62.
A new simple and sensitive in-vitro method for the diagnosis of type 1 (IgE-mediated) hypersensitivity in man is described. Sliced human skin is passively sensitized by reaginic serum from allergic patients and the presence of antigen-specific IgE on the sensitized slices is detected by assay of antigen-evoked histamine release. Serum from 12 out of 14 patients with clinical respiratory allergy and positive skin tests gave significant antigen-specific histamine release. This method, which is essentially an in-vitro model of the Prausnitz-Küstner reaction, should prove of value in the diagnosis of human reaginic hypersensitivity in man. 相似文献
63.
64.
65.
66.
67.
68.
Relative Activities of NAD- and NADP-Isocitric Dehydrogenases in Bean Mitochondria Modified by Glycerol or NADP 下载免费PDF全文
Yukio Yamamoto 《Plant physiology》1969,44(2):262-266
Mitochondria from cotyledons of Vigna sesquipedalis (L.) Fruwirth (starchy seed) showed no NAD-isocitric dehydrogenase (NAD-IDH) activity by the methods which have been known to be useful for the detection of NAD-IDH in mitochondria of plants including castor bean and alaska pea. When the Vigna cotyledon mitochondria were treated with glycerol, NAD-IDH activity appeared and NADP-isocitric dehydrogenase (NADP-IDH) activity was inhibited. The inhibition of mitochondrial NADP-IDH by glycerol was overcome by the addition of excess NADP.On the other hand, NADP-IDH activity in the soluble fraction of cell components was only slightly inhibited by glycerol and no NAD-IDH activity was elicited.It was postulated that NADP-IDH in mitochondria is converted to NAD-IDH by glycerol and back to NADP-IDH with NADP by the alteration in the spatial configuration of the enzyme. However, there could be 2 proteins as the other possibility.The NADP-IDH in the soluble fraction which is not subject to such alteration is different from the mitochondrial NADP-IDH. 相似文献
69.
70.