全文获取类型
收费全文 | 407767篇 |
免费 | 37582篇 |
国内免费 | 942篇 |
出版年
2018年 | 14109篇 |
2017年 | 12833篇 |
2016年 | 10902篇 |
2015年 | 5626篇 |
2014年 | 6258篇 |
2013年 | 8910篇 |
2012年 | 13614篇 |
2011年 | 22048篇 |
2010年 | 18059篇 |
2009年 | 13813篇 |
2008年 | 17893篇 |
2007年 | 19782篇 |
2006年 | 8614篇 |
2005年 | 8560篇 |
2004年 | 9102篇 |
2003年 | 8874篇 |
2002年 | 8542篇 |
2001年 | 14524篇 |
2000年 | 14475篇 |
1999年 | 11496篇 |
1998年 | 4026篇 |
1997年 | 4151篇 |
1996年 | 3936篇 |
1995年 | 3800篇 |
1994年 | 3804篇 |
1993年 | 3718篇 |
1992年 | 9825篇 |
1991年 | 9423篇 |
1990年 | 9218篇 |
1989年 | 8946篇 |
1988年 | 8364篇 |
1987年 | 7998篇 |
1986年 | 7213篇 |
1985年 | 7320篇 |
1984年 | 6050篇 |
1983年 | 5319篇 |
1982年 | 4177篇 |
1981年 | 3692篇 |
1980年 | 3512篇 |
1979年 | 6094篇 |
1978年 | 4548篇 |
1977年 | 4272篇 |
1976年 | 3968篇 |
1975年 | 4300篇 |
1974年 | 4651篇 |
1973年 | 4716篇 |
1972年 | 4590篇 |
1971年 | 4324篇 |
1970年 | 3440篇 |
1969年 | 3334篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
901.
902.
Feather samples from 117 birds, representing 11 species, were examined for keratinophilic fungi. Of these, 63 (53.8%) were found to be positive. Nine species of fungi classified in 6 genera were isolated: Aphanoascus terreus (1.7%), Chrysosporium indicum (26.4%), Chrys. tropicum (11.1%) the Chrysosporium state of Aphanoascus spp. (2.5%), the Chrysosporium state of Arthroderma tuberculatum (3.4%), Ctenomyces serratus (0.8%), Gymnoascoideus petalosporus (7.6%), Malbranchea spp. (6.8%), Rollandina hyalinospora (6.8%). Passer domesticus (the house sparrow) harboured the largest varieties of keratinophilic fungi: the Chrysosporium state of Arthroderma tuberculatum was found to be associated with it selectively. The associations of these keratinophilic fungi with birds were non-clinical in nature. 相似文献
903.
904.
905.
Kevin B. Potts 《Journal of Mammalian Evolution》2010,17(3):221-222
906.
907.
A high molecular weight glycoprotein (450,000) was obtained from thrombin-treated duck thrombocytes by barium citrate adsorption technique followed by heparin-agarose affinity chromatography. Amino acid composition (high number of acidic amino acids and cystine) as well as carbohydrate contents (1.3 per cent hexosamine, 0.9 per cent sialic acid and 1.5 per cent hexose) showed similarity to mammalian platelet thrombospondin. 相似文献
908.
909.
Medical skills should be developed by the staffs of smaller hospitals for the differential study of patients with symptoms resembling those of poliomyelitis in order to provide the rudiments of care for the occasional patient with mild poliomyelitis, to recognize the indications which point to the necessity of superior technical assistance, and to decide when it is appropriate to move patients to better equipped centers. The impetuous acquisition of mechanical aids for the treatment of special problems will be effective in small communities only to the extent that this equipment is kept serviceable and is operated by persons of sufficient skill. Epidemic situations in a small community can be met only by mobilization of facilities under adequate direction and by integration of care with that provided by larger treatment centers. 相似文献
910.