全文获取类型
收费全文 | 2947篇 |
免费 | 456篇 |
国内免费 | 11篇 |
出版年
2021年 | 48篇 |
2018年 | 35篇 |
2017年 | 35篇 |
2016年 | 51篇 |
2015年 | 69篇 |
2014年 | 107篇 |
2013年 | 93篇 |
2012年 | 137篇 |
2011年 | 138篇 |
2010年 | 107篇 |
2009年 | 60篇 |
2008年 | 133篇 |
2007年 | 106篇 |
2006年 | 110篇 |
2005年 | 97篇 |
2004年 | 92篇 |
2003年 | 98篇 |
2002年 | 80篇 |
2001年 | 95篇 |
2000年 | 81篇 |
1999年 | 93篇 |
1998年 | 53篇 |
1997年 | 37篇 |
1996年 | 35篇 |
1995年 | 31篇 |
1993年 | 33篇 |
1992年 | 63篇 |
1991年 | 70篇 |
1990年 | 65篇 |
1989年 | 70篇 |
1988年 | 57篇 |
1987年 | 69篇 |
1986年 | 58篇 |
1985年 | 68篇 |
1984年 | 36篇 |
1983年 | 55篇 |
1982年 | 32篇 |
1981年 | 44篇 |
1980年 | 31篇 |
1979年 | 38篇 |
1978年 | 40篇 |
1976年 | 50篇 |
1975年 | 36篇 |
1974年 | 37篇 |
1973年 | 37篇 |
1972年 | 46篇 |
1971年 | 40篇 |
1969年 | 24篇 |
1968年 | 26篇 |
1857年 | 31篇 |
排序方式: 共有3414条查询结果,搜索用时 171 毫秒
1.
The sequential cytological events of the regeneration process, after partial excision of the gastrocnemius muscle in the rat, were followed by light and electron microscopy. During the first 2 days after injury leukocytes and macrophages infiltrate into the traumatized area. Myogenic regeneration is then characterized by mainly two repair mechanisms. Mononucleated cells, that populate the excised area, most probably fuse together to give rise to newly formed multinucleated myotubes that further develop to striated myofibers. Another mechanism involves the repair of injured muscle fibers by the possible fusion of mononucleated cells with their necrotic cut ends. Consequently, by addition of nuclei and new muscular material, sarcoplasmic outgrowths from the injured fibers are formed. It is concluded that mainly two repair mechanisms are involved in the regeneration process following partial excision of a muscle: addition of new muscle fibers in a process similar to that of embryonic myogenesis and also meristic growth from the injured fibers. 相似文献
2.
Chromosomal RNA: an artifact of preparation? 总被引:2,自引:0,他引:2
3.
ACTH stimulation of adenyl cyclase in adrenal homogenates 总被引:6,自引:0,他引:6
4.
5.
6.
肺癌在中国恶性肿瘤的发病率位居第一,随着低剂量薄层CT在肺癌筛查中的广泛应用,临床发现更多表现为非完全实性结节的肺腺癌,目前众多研究使CT影像学特征和肺腺癌病理的关系得到更进一步的认知,虽然CT能对部分非完全实性结节做出定性和定位诊断,但仍有部分非完全实性结节诊断困难,PET-CT结合了病灶的代谢信息和精确的定位信息,从而提高对肺部结节诊断的敏感性、特异性、准确性,综合多个文献PET-CT在非完全实性结节中的诊断分期价值较CT无明显提升,却在评估预后和制定合适手术方案上可以起到一定的作用,本文就PET-CT在SSN中的应用价值进行阐述。 相似文献
7.
Expression patterns of the T antigen and the cryptic T antigen in rat fetuses: detection with the lectin amaranthin 总被引:4,自引:0,他引:4
T Sata C Zuber S J Rinderle I J Goldstein J Roth 《The journal of histochemistry and cytochemistry》1990,38(6):763-774
The lectin amaranthin, purified from the seeds of Amaranthus caudatus, has been shown to react specifically with the Gal beta 1,3GalNAc-alpha and the NeuAc alpha 2,3Gal beta 1,3GalNAc-alpha sequence which represent the T antigen and the cryptic T antigen, respectively. We report here the development of labeling techniques that apply amaranthin to stain paraffin sections from rat fetuses. Amaranthin staining was inhibited by pre-incubation of lectin-gold complexes with 10 mM Gal beta 1,3GalNAc-alpha-O-benzyl (synthetic T antigen) or 10 mM Gal beta 1,3GalNAc-alpha-O-aminophenylethyl-human serum albumin (T antigen neoglycoprotein), asialoglycophorin, asialofetuin, and asialomucin. The beta-elimination reaction also abolished the lectin staining demonstrating specificity for O-glycosidically linked structures. A comparison with monoclonal anti-T antigen antibody immunostaining demonstrated that amaranthin detects the T antigen and its cryptic form in tissue sections. Application of the galactose oxidase-Schiff sequence abolished amaranthin (and anti-T antibody) binding to the T antigen but not to its cryptic form, and therefore permitted their differentiation in tissue sections. Histochemical evidence was obtained indicating that amaranthin is a more specific anti-T reagent than peanut lectin. Data are presented that show the differential expression of the T antigen and the cryptic T antigen in organs and cells of rat fetuses late in gestation. Therefore, amaranthin can be used for histochemical detection of the T antigen and the cryptic T antigen, and facilitates discrimination between them. 相似文献
8.
New series of lipoxins isolated from human eosinophils 总被引:1,自引:0,他引:1
Granulocytes from human eosinophilic donors were incubated with arachidonic acid or 15-hydroxyeicosatetraenoic acid (15-HETE) and stimulated with the ionophore A23187. The eicosanoids were extracted with reversed-phase cartridges and subjected to RP-HPLC analysis. When extracts from eosinophil-enriched populations were analysed and compared with extracts from human neutrophils, three additional peaks were detected which coeluted with 15-hydroxy-delta 13-trans-15H derivatives of leukotriene C4, D4 and E4 in different HPLC systems. The recorded absorbance spectra of the eluted compounds and the standards were identical and showed a maximum at 307 nm which is characteristic for a conjugated tetraene system with a bathochromic shift by the sulfur moiety in alpha-position to the tetraene system. The compound which coeluted with the 15-hydroxy-LTC4 standard was treated with gamma-glutamyltransferase and converted to the corresponding leukotriene D4 derivative. The results indicate that interaction between the 5- and 15-lipoxygenase pathways leads to the formation of a new series of arachidonic acid metabolites in human eosinophils. Since the biosynthetic route is similar to that of lipoxin A4 and lipoxin B4, we suggest the trivial names lipoxin C4, D4 and E4. 相似文献
9.
10.