全文获取类型
收费全文 | 228945篇 |
免费 | 14995篇 |
国内免费 | 49篇 |
专业分类
243989篇 |
出版年
2021年 | 1773篇 |
2018年 | 3125篇 |
2017年 | 3024篇 |
2016年 | 3666篇 |
2015年 | 3201篇 |
2014年 | 4438篇 |
2013年 | 6322篇 |
2012年 | 7581篇 |
2011年 | 8163篇 |
2010年 | 5749篇 |
2009年 | 4877篇 |
2008年 | 7281篇 |
2007年 | 7579篇 |
2006年 | 7266篇 |
2005年 | 6810篇 |
2004年 | 6952篇 |
2003年 | 6696篇 |
2002年 | 6650篇 |
2001年 | 9384篇 |
2000年 | 9100篇 |
1999年 | 7106篇 |
1998年 | 2132篇 |
1997年 | 1959篇 |
1996年 | 1820篇 |
1992年 | 5624篇 |
1991年 | 5881篇 |
1990年 | 5866篇 |
1989年 | 5819篇 |
1988年 | 5442篇 |
1987年 | 5068篇 |
1986年 | 4635篇 |
1985年 | 4850篇 |
1984年 | 3819篇 |
1983年 | 3146篇 |
1982年 | 2056篇 |
1981年 | 1761篇 |
1980年 | 1757篇 |
1979年 | 3439篇 |
1978年 | 2665篇 |
1977年 | 2446篇 |
1976年 | 2429篇 |
1975年 | 2951篇 |
1974年 | 3252篇 |
1973年 | 3233篇 |
1972年 | 2888篇 |
1971年 | 2707篇 |
1970年 | 2322篇 |
1969年 | 2243篇 |
1968年 | 2141篇 |
1967年 | 1895篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
961.
MICHAEL D. BAKER CHARLES R. VOSSBRINCK JAMES J. BECNEL JOSEPH V. MADDOX 《The Journal of eukaryotic microbiology》1997,44(3):220-225
ABSTRACT. Sequences of the small subunit rRNA genes of Amblyospora californica and an Amblyospora sp. from Culex salinarius were determined. These sequences were compared phylogenetically with 16 other microsporidia. The results suggest Amblyospora forms a sister taxon to the rest of the microsporidia examined. The basal position of Amblyospora is discussed with respect to the evolution of microsporidian life cycles. These sequences represent the longest microsporidian small subunit rRNA genes sequenced to date, 1,359 and 1,358 bp, respectively. Structural features and GC content (49% for both) are comparable to those of other microsporidia which have been sequenced. 相似文献
962.
963.
964.
965.
966.
967.
The data presented in this work indicate that specific antisera to P. aeruginosa and Proteus antigens can be produced by using extracts from these microorganisms, destroyed by ultrasonic treatment or by multiple freezing and thawing, for the immunization of rabbits. Blood serum samples from patients with purulent septic complications were studied for the presence of P. aeruginosa and Proteus antigens in ELISA with the use of peroxidase-labeled antibodies from antisera to P. aeruginosa and Proteus. This investigation revealed that during the first 3 days from the beginning of the clinical manifestations of the complications P. aeruginosa and Proteus antigens were detected in 86.4% and 83.4% of the patients, respectively. In the subsequent bacteriological study of wound discharge from these patients the corresponding microflora was detected. 相似文献
968.
969.
V N Gorbacheva N I Lebedev M V Miakinnikova T M Ovcharenko 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1982,(9):42-45
Clinical, bacteriological, serological and epidemiological studies of ozena morbidity among the population of Minsk were carried out in 1970-1980. On January 1, 1981, the ozena morbidity rate among the inhabitants of Minsk was 26.72%. Ozena was found to affect mainly children and women. A wide spread of the family foci of this disease (31.68%) was revealed. The results of this study indicate that the source of K. ozaenae is a sick person who begins to excrete the bacteria in the prodromal period of the disease and may continue to excrete them for many years. The transfer of K. ozaenae occurs probably by droplet or contact infection. The droplet infection is less active in the absence of symptoms (coughing, sneezing) facilitating excretion of the infective agent into the air and in cases of the low susceptibility of persons to ozena. The main measures for controlling ozena are the timely detection and sanitation of the sources of ozena, as well as the current disinfection of the infection foci in apartments. 相似文献
970.