全文获取类型
收费全文 | 8087篇 |
免费 | 738篇 |
国内免费 | 1篇 |
出版年
2023年 | 48篇 |
2022年 | 145篇 |
2021年 | 269篇 |
2020年 | 136篇 |
2019年 | 129篇 |
2018年 | 162篇 |
2017年 | 152篇 |
2016年 | 253篇 |
2015年 | 370篇 |
2014年 | 431篇 |
2013年 | 521篇 |
2012年 | 653篇 |
2011年 | 678篇 |
2010年 | 371篇 |
2009年 | 324篇 |
2008年 | 393篇 |
2007年 | 415篇 |
2006年 | 396篇 |
2005年 | 341篇 |
2004年 | 296篇 |
2003年 | 303篇 |
2002年 | 290篇 |
2001年 | 98篇 |
2000年 | 90篇 |
1999年 | 105篇 |
1998年 | 74篇 |
1997年 | 62篇 |
1996年 | 48篇 |
1995年 | 43篇 |
1994年 | 37篇 |
1993年 | 40篇 |
1992年 | 62篇 |
1991年 | 45篇 |
1990年 | 49篇 |
1989年 | 47篇 |
1988年 | 31篇 |
1987年 | 55篇 |
1986年 | 60篇 |
1985年 | 58篇 |
1984年 | 64篇 |
1983年 | 77篇 |
1982年 | 55篇 |
1981年 | 62篇 |
1980年 | 68篇 |
1979年 | 41篇 |
1978年 | 34篇 |
1977年 | 31篇 |
1976年 | 32篇 |
1974年 | 30篇 |
1973年 | 29篇 |
排序方式: 共有8826条查询结果,搜索用时 281 毫秒
141.
D W Green R Aschaffenburg A Camerman J C Coppola P Dunnill R M Simmons E S Komorowski L Sawyer E M Turner K F Woods 《Journal of molecular biology》1979,131(2):375-397
Bovine β-lactoglobulin is a dimer with a molecular weight of 2 × 18,400. In solution it undergoes a pH-dependent transition at pH 7.0 between two alternative structures, named N and R. The structures of four different crystal forms have been determined by multiple isomorphous replacement with heavy-atoms. Two of them, lattices K and X, were crystallised at pH 6.5, corresponding to the N state in solution; and the other two, lattices Y and Z, were crystallised at pH 7.5, corresponding to the R state in solution. The figures of merit of the phase angles determined for these lattices were 0.76, 0.77, 0.80 and 0.80, respectively. The four structures that emerged are similar and show certain features suggestive of α-helices and pleated sheets, but the resolution is insufficient to trace the entire course of the polypeptide chain. No clear distinction can yet be made between the structures above or below pH 7.0, nor between the native molecule and the molecule from which the C-terminal leucine and histidine residues have been cleaved. Analyses at higher resolution are in progress. 相似文献
142.
J E Woods P G Arnold J K Masson G B Irons W S Payne 《Plastic and reconstructive surgery》1979,63(2):235-241
Aggressive resection, with individualized reconstruction by several methods, is of value in many patients with radiation necrosis and/or advanced breast cancer of the chest wall. Although this does not always significantly lengthen survival, it can improve the quality of life markedly in many instances. Remarkably large defects can be reconstructed with single-stage procedures. 相似文献
143.
144.
145.
146.
147.
148.
149.
150.
Levels of the factor VIII complex were found to be raised in patients with chronic renal failure and further raised by regular dialysis. Increased fibrinogen concentrations were also found. These results suggest the existence of a prothrombotic state in uraemia that is exacerbated by haemodialysis. Ristocetin-induced platelet agglutination, however, was depressed in uraemia and worsened by dialysis. This defect may be transferred to normal platelets from dialysed uraemic plasma, suggesting the existence of an inhibitor of the interaction between factor VIII and platelet glycoprotein. These results may help to explain the anomaly of a prolonged bleeding time together with accelerated atherogenesis that is found in patients with uraemia receiving dialysis. 相似文献