全文获取类型
收费全文 | 1647篇 |
免费 | 219篇 |
国内免费 | 1篇 |
出版年
2021年 | 19篇 |
2020年 | 21篇 |
2019年 | 45篇 |
2018年 | 35篇 |
2016年 | 28篇 |
2015年 | 34篇 |
2014年 | 34篇 |
2013年 | 66篇 |
2012年 | 40篇 |
2011年 | 70篇 |
2010年 | 43篇 |
2009年 | 44篇 |
2008年 | 61篇 |
2007年 | 64篇 |
2006年 | 60篇 |
2005年 | 55篇 |
2004年 | 31篇 |
2003年 | 45篇 |
2002年 | 52篇 |
2001年 | 54篇 |
2000年 | 32篇 |
1999年 | 43篇 |
1998年 | 41篇 |
1997年 | 24篇 |
1996年 | 28篇 |
1995年 | 26篇 |
1994年 | 15篇 |
1993年 | 23篇 |
1992年 | 34篇 |
1991年 | 36篇 |
1990年 | 24篇 |
1989年 | 48篇 |
1988年 | 32篇 |
1987年 | 38篇 |
1985年 | 28篇 |
1984年 | 25篇 |
1983年 | 29篇 |
1982年 | 21篇 |
1981年 | 30篇 |
1980年 | 23篇 |
1979年 | 22篇 |
1978年 | 18篇 |
1977年 | 28篇 |
1976年 | 17篇 |
1975年 | 24篇 |
1974年 | 16篇 |
1973年 | 22篇 |
1972年 | 29篇 |
1971年 | 17篇 |
1970年 | 19篇 |
排序方式: 共有1867条查询结果,搜索用时 15 毫秒
1.
2.
3.
H R Warner 《Journal of bacteriology》1983,154(3):1451-1454
The thermophile Thermus sp. strain X-1, grown at 70 degrees C, contains uracil-DNA glycosylase and apurinic endonuclease activities, both of which are known to have roles in the repair of DNA damaged by heat. Both of these activities have temperature optima of about 70 degrees C. However, neither of these activities is present in quantities significantly greater than that found in Escherichia coli grown at 37 degrees C. Therefore, it appears that thermophilic organisms may not contain greatly elevated levels of the enzymes thought to be involved in the repair of DNA damaged by heat. 相似文献
4.
A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan. 相似文献
5.
6.
7.
8.
9.
10.
Margot S. Kruskall MD Elizabeth E. Eynon Zuheir Awdeh Chester A. Alper Edmond J. Yunis 《Immunogenetics》1987,26(4-5):216-219
The HLA class I antigen B44 is found in each of two different extended major histocompatibility haplotypes (allele combinations of HLA-B, HLA-DR, and complement genes BF, C2, C4A, and C4B in linkage disequilibrium). Using isoelectric focusing, two variants of HLA-B44 were identified. The basic variant was found in all cell lines with the extended haplotype HLA-B44, DR7, FC31, and the acidic variant in all cell lines with the extended haplotype HLA-B44, DR4, SC30. The occurrence of each antigen variant with a unique extended haplotype explains previous observations concerning the nonrandom association of B44 variants with DR antigens. 相似文献