全文获取类型
收费全文 | 3319篇 |
免费 | 203篇 |
国内免费 | 13篇 |
出版年
2023年 | 17篇 |
2022年 | 32篇 |
2021年 | 96篇 |
2020年 | 71篇 |
2019年 | 86篇 |
2018年 | 118篇 |
2017年 | 96篇 |
2016年 | 128篇 |
2015年 | 204篇 |
2014年 | 201篇 |
2013年 | 253篇 |
2012年 | 288篇 |
2011年 | 274篇 |
2010年 | 151篇 |
2009年 | 132篇 |
2008年 | 165篇 |
2007年 | 179篇 |
2006年 | 131篇 |
2005年 | 113篇 |
2004年 | 105篇 |
2003年 | 76篇 |
2002年 | 82篇 |
2001年 | 60篇 |
2000年 | 69篇 |
1999年 | 47篇 |
1998年 | 25篇 |
1997年 | 22篇 |
1996年 | 22篇 |
1995年 | 13篇 |
1994年 | 7篇 |
1993年 | 14篇 |
1992年 | 22篇 |
1991年 | 27篇 |
1990年 | 18篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 10篇 |
1986年 | 16篇 |
1985年 | 9篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1957年 | 6篇 |
1953年 | 7篇 |
排序方式: 共有3535条查询结果,搜索用时 15 毫秒
1.
2.
The involvement of gibberellins in the control of flowering of sunflower was studied by direct application of GA3 to the apex of the plants, analysis of the endogenous levels of gibberellin-like substances at different plant ages, and indirectly by the application of paclobutrazol, an inhibitor of gibberellin synthesis. GA3 speeded-up flower initiation and floral apex development. The time of GA3 application was more critical than the amount of GA3 applied. The endogenous levels of gibberellin-like compounds increased significantly by day 15 after sowing. The application of paclobutrazol markedly delayed floral initiation and this effect was also depedent on plant age. Both GA3 and paclobutrazol had their greatest effects between 10 and 20 days after sowing suggesting that an increase in gibberellins in that time period plays a role in floral initiation. 相似文献
3.
Cassandre Leverrier Giana Almeida Lucia Espinosa-Mu noz Gérard Cuvelier 《Food biophysics》2016,11(3):235-247
This work investigates the impact of structural parameters on the rheological behaviour of apple purees. Reconstructed apple purees from 0 g/100 g up to 2.32 g/100 g of insoluble solids content and varying in particle size were prepared. Three different particle size distributions were obtained by mechanical treatment only, to modify both size and morphology of the particles without modifying the intrinsic rigidity of the cell walls. Rheological measurements showed that the insoluble solids content have a first order effect on the rheological behaviour of the suspensions: three concentrations domains were observed in both dynamic and flow measurements. A model is proposed for each domain. The existence of a weak network between particles is clearly shown over a critical concentration of insoluble solids (cell walls) depending on particle size distribution (semi-diluted domain). In a concentrated domain, particles are on close packing conditions and their apparent volume begin to shrink. Particle size and shape also play an important role on the rheological behaviour of reconstructed apple puree. Due to their irregular shape, cell clusters clog the medium at lower concentration compared to individual cells. 相似文献
4.
5.
6.
7.
8.
9.
Almeida AP 《Theriogenology》1987,27(2):329-335
A comparison between different superovulatory treatments in dairy cattle was carried out at a commercial embryo transfer unit in Israel. Both pregnant mare serum gonadotrophin (PMSG) and follicle stimulating hormone (FSH) were used, either alone or combined with Syncromate B (SMB). The use of PMSG + SMB significantly decreased the number of corpora lutea present at the time of embryo collection 7 d after insemination, as compared with other treatment regimens. Consequently, a significantly lower number of ova was found in those animals treated with PMSG + SMB. Better superovulatory responses were obtained when FSH, rather than PMSG, was used, regardless of whether they were administered alone or combined with SMB. It was clear that the use of SMB combined either with PMSG or FSH resulted in poorer responses than when either gonadotrophin was used alone. 相似文献
10.
Alberto Barros M. Carmo Tavares Sérgio Castedo M. Salomé Pereira M. Purificação Tavares M. Almeida e Costa 《Human genetics》1987,75(4):388-390
Summary A double balanced reciprocal translocation involving four chromosomes, t(1;19;6;14) (1p11; 19p11; 6q25; 14q21), was found in the phenotypically normal husband in a couple referred because of repeated abortions. Reciprocal translocations, t(6;14), had been transmitted by his mother, his father being apparently homozygous for a translocation comprising pairs 1 and 19-t(1;19)(1;19). The genetic consequences of this complex chromosomal rearrangement are analyzed. 相似文献