全文获取类型
收费全文 | 448305篇 |
免费 | 55664篇 |
国内免费 | 280篇 |
出版年
2018年 | 3822篇 |
2017年 | 3505篇 |
2016年 | 5457篇 |
2015年 | 8168篇 |
2014年 | 9153篇 |
2013年 | 12865篇 |
2012年 | 14839篇 |
2011年 | 14949篇 |
2010年 | 9866篇 |
2009年 | 9127篇 |
2008年 | 13045篇 |
2007年 | 13522篇 |
2006年 | 12225篇 |
2005年 | 12033篇 |
2004年 | 11802篇 |
2003年 | 11242篇 |
2002年 | 10747篇 |
2001年 | 21628篇 |
2000年 | 21754篇 |
1999年 | 17387篇 |
1998年 | 6214篇 |
1997年 | 6468篇 |
1996年 | 6295篇 |
1995年 | 5693篇 |
1994年 | 5748篇 |
1993年 | 5566篇 |
1992年 | 13644篇 |
1991年 | 12957篇 |
1990年 | 12639篇 |
1989年 | 12494篇 |
1988年 | 11157篇 |
1987年 | 10781篇 |
1986年 | 9868篇 |
1985年 | 9647篇 |
1984年 | 8180篇 |
1983年 | 7067篇 |
1982年 | 5519篇 |
1981年 | 5000篇 |
1980年 | 4648篇 |
1979年 | 7682篇 |
1978年 | 5914篇 |
1977年 | 5425篇 |
1976年 | 5061篇 |
1975年 | 5362篇 |
1974年 | 5806篇 |
1973年 | 5655篇 |
1972年 | 5099篇 |
1971年 | 4725篇 |
1970年 | 3920篇 |
1969年 | 3848篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
C Chechan X Marchandise J Lekieffre 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(4):991-996
The mean of Rubidium rates in human plasma is found in the range of 0,1 mg/l with poor fluctuations; it is significantly less in woman than in man. There is a good linear correlation between rates in plasma and in red cell, rates which are in the same relation than potassium ones. Mean urinary clearance of rubidium is 16 ml/mm but there are large variations. 相似文献
202.
203.
204.
205.
206.
207.
Three hundred and thirty specimens of 7 species of passerine birds from South Bass Island, Ottawa County, Ohio, were examined for helminth parasites. The total number of helminth specimens collected was 4,333. Forty-one helminth taxa were identified. Ten species of helminths were identified as having foci of infection on the island. An index of association for these 10 species is presented. The low association revealed between helminth species utilizing common species of intermediate hosts indicated that a single intermediate host specimen is likely to harbor infective stages of only one species of parasitic helminth. An index of similarity is presented to express the species importance relationships of the helminth faunas of the 7 species of birds: red-winged blackbirds (Agelaius phoeniceus), blue jays (Cyanocitta cristata), brown-headed cowbirds (Molothrus ater), common grackles (Quiscalus quiscula), house sparrows (Passer domesticus), starlings (Sturnus vulgaris), and robins (Turdus migratorius). The results reveal that competition between these avian species for invertebrate food resources helps to maximize the transmission of those helminth populations which utilize these same invertebrates as intermediate hosts. The aggregation of birds into mixed feeding flocks insures a heavy loading of the feeding grounds with agents infective for the invertebrate populations. 相似文献
208.
209.
210.
S. Renaud S. Guillemard M.-C. Eberlé-Pouzeratte C. Lemanski P. Faurous J.-C. Artus 《Médecine Nucléaire》2009,33(7):415-424
ObjectiveTo evaluate the contribution of FDG-PET in the management of anal carcinoma, with special emphasis on its impact on therapeutic strategy.Materials and methodsFrom March 2005 to August 2008, 48 PET were performed on 43 patients with anal epidermoid carcinoma, in initial staging (IS: 20 exams), therapeutic response assessment (TRA: 11), and recurrence assessment (RA: 17). We compared initial therapeutic strategies defined on conventional assessment results, to final ones chosen after PET.ResultsPET revealed lesions that were undetected by conventional investigation in 23% of cases (IS: 25%; TRA: 18%; RA: 23%) and cleared suspicious lesions in 21% of cases (IS: 10%; TRA: 18%; RA: 35%). It influenced the therapeutic strategy, and sometimes even modified it radically, in 44% of cases (IS: 35%; TRA: 54%; RA: 47%). This therapeutic impact was stronger in settings with diagnostic ambiguity, in which PET allowed to specify the diagnosis and to orientate consequently the therapeutic choice.ConclusionPET is interesting in the management of anal carcinoma, especially in uncertain diagnostic settings, in which the metabolic information brought allows to influence the therapeutic choice in almost half of the cases. 相似文献