全文获取类型
收费全文 | 777篇 |
免费 | 70篇 |
专业分类
847篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 28篇 |
2012年 | 38篇 |
2011年 | 38篇 |
2010年 | 29篇 |
2009年 | 20篇 |
2008年 | 33篇 |
2007年 | 32篇 |
2006年 | 27篇 |
2005年 | 31篇 |
2004年 | 33篇 |
2003年 | 27篇 |
2002年 | 22篇 |
2001年 | 19篇 |
2000年 | 22篇 |
1999年 | 15篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1992年 | 7篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 19篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1982年 | 5篇 |
1960年 | 6篇 |
1947年 | 5篇 |
1938年 | 7篇 |
1936年 | 11篇 |
1935年 | 7篇 |
1933年 | 9篇 |
1932年 | 10篇 |
1931年 | 10篇 |
1929年 | 7篇 |
1923年 | 4篇 |
1920年 | 5篇 |
1918年 | 4篇 |
排序方式: 共有847条查询结果,搜索用时 15 毫秒
841.
Reconstruction of the eyebrow in the pediatric burn patient 总被引:2,自引:0,他引:2
We have reviewed our experience with reconstruction of eyebrow alopecia secondary to thermal injury in the pediatric patient. Reconstruction was performed with free composite strip grafts or vascularized island pedicle flaps. The complication rates for eyebrows reconstructed with vascularized island pedicles with respect to loss of a significant portion of the flaps (30.8 percent) and malalignment of the grafts (23.1 percent) were significantly greater (p less than 0.001) than the significant tissue loss (10.6 percent) or graft malalignment (7.9 percent) observed for free composite grafts. Hair density was more predictably restored with the free composite graft technique (p = 0.0004). The patients reconstructed with composite grafts had 89.4 percent acceptable results in contrast to 38.5 percent acceptable results obtained with the island pedicle technique. Based on these findings, we reserve the use of the vascularized island pedicle technique for male patients with unilateral alopecia and heavy hair density in the remaining eyebrow and in cases where free composite grafts have failed. The remaining patients are initially treated with free composite grafts with acceptable results in the overwhelming majority of cases. 相似文献
842.
Environmental temperature strongly affects physiology of ectotherms. Small ectotherms, like Drosophila, cannot endogenously regulate body temperature so must rely on behavior to maintain body temperature within a physiologically permissive range. Here we review what is known about Drosophila thermal preference. Work on thermal behavior in this group is particularly exciting because it provides the opportunity to connect genes to neuromolecular mechanisms to behavior to fitness in the wild. 相似文献
843.
S Weiner A Veis E Beniash T Arad J W Dillon B Sabsay F Siddiqui 《Journal of structural biology》1999,126(1):27-41
Peritubular dentin (PTD) is a relatively dense mineralized tissue that surrounds the tubules of coronal tooth dentin. It is composed mainly of crystals of carbonated apatite together with a small amount of collagen. Its mode of formation has been investigated by studying the relatively dense particles isolated from a powdered preparation. Electron microscopic examination of the PTD particles, including 3-dimensional image reconstruction and electron diffraction, shows that the organization of the crystals of PTD is very similar to that of the adjacent intertubular dentin (ITD). The latter contains relatively large amounts of collagen and the carbonated apatite crystals are closely associated with the collagen matrix. The proteins present in the PTD particles are soluble after decalcification and stain with Stains All. The principal protein has higher molecular weight and a quite different amino acid composition than the phosphophoryns of the intertubular dentin. The interface between the PTD and the ITD shows structural continuity. These data show how two distinct carbonated apatite-based mineralized tissues can be organized and formed contiguously within the same organ by utilizing different sets of matrix proteins. 相似文献
844.
845.
Two male siblings presented in infancy with hyponatraemia. Levels of plasma renin activity and aldosterone were elevated. Sodium supplementation was necessary to maintain normal sodium balance. Urinary sodium concentration and renal epithelial exchange between sodium and potassium were normal; however, salivary sodium concentrations were markedly elevated with sweat sodium levels being in the upper normal range. Excess salivary sodium loss accounted for sodium depletion in these cases who present a new variant of pseudohypoaldosteronism associated with normal renal sodium transport. 相似文献
846.
847.
A new species,Symplocos incahuasensis Sagást. & Dillon, is described and illustrated, and its relationships are discussed. A key to the small-leaved Peruvian species
is provided. 相似文献