全文获取类型
收费全文 | 4618篇 |
免费 | 279篇 |
国内免费 | 3篇 |
出版年
2022年 | 25篇 |
2021年 | 51篇 |
2020年 | 29篇 |
2019年 | 53篇 |
2018年 | 53篇 |
2017年 | 67篇 |
2016年 | 100篇 |
2015年 | 137篇 |
2014年 | 155篇 |
2013年 | 283篇 |
2012年 | 272篇 |
2011年 | 271篇 |
2010年 | 181篇 |
2009年 | 187篇 |
2008年 | 254篇 |
2007年 | 263篇 |
2006年 | 240篇 |
2005年 | 253篇 |
2004年 | 253篇 |
2003年 | 239篇 |
2002年 | 233篇 |
2001年 | 102篇 |
2000年 | 81篇 |
1999年 | 94篇 |
1998年 | 44篇 |
1997年 | 52篇 |
1996年 | 44篇 |
1995年 | 36篇 |
1994年 | 27篇 |
1993年 | 48篇 |
1992年 | 84篇 |
1991年 | 68篇 |
1990年 | 52篇 |
1989年 | 68篇 |
1988年 | 47篇 |
1987年 | 37篇 |
1986年 | 50篇 |
1985年 | 41篇 |
1984年 | 40篇 |
1983年 | 32篇 |
1982年 | 35篇 |
1981年 | 24篇 |
1980年 | 15篇 |
1979年 | 22篇 |
1978年 | 20篇 |
1976年 | 14篇 |
1975年 | 16篇 |
1974年 | 16篇 |
1972年 | 14篇 |
1970年 | 12篇 |
排序方式: 共有4900条查询结果,搜索用时 781 毫秒
41.
Differential expression and distribution of chicken skeletal- and smooth-muscle-type alpha-actinins during myogenesis in culture 总被引:13,自引:11,他引:2 下载免费PDF全文
Antibodies to chicken fast skeletal muscle (pectoralis) alpha-actinin and to smooth muscle (gizzard) alpha-actinin were absorbed with opposite antigens by affinity chromatography, and four antibody fractions were thus obtained: common antibodies reactive with both pectoralis and gizzard alpha-actinins ([C]anti-P alpha-An and [C]anti-G alpha-An), antibody specifically reactive with pectoralis alpha-actinin ([S]anti-P alpha-An), and antibody specifically reactive with gizzard alpha-actinin ([S]anti-G alpha-An). In indirect immunofluorescence microscopy, (C)anti-P alpha-An, (S)anti-P alpha-An, and (C)anti-G alpha- An stained Z bands of skeletal muscle myofibrils, whereas (S)anti-G alpha-An did not. Although (S)anti-G alpha-An and two common antibodies stained smooth muscle cells, (S)anti-P alpha-An did not. We used (S)anti-P alpha-An and (S)anti-G alpha-An for immunofluorescence microscopy to investigate the expression and distribution of skeletal- and smooth-muscle-type alpha-actinins during myogenesis of cultured skeletal muscle cells. Skeletal-muscle-type alpha-actinin was found to be absent from myogenic cells before fusion but present in them after fusion, restricted to Z bodies or Z bands. Smooth-muscle-type alpha- actinin was present diffusely in the cytoplasm and on membrane- associated structures of mononucleated and fused myoblasts, and then confined to membrane-associated structures of myotubes. Immunoblotting and peptide mapping by limited proteolysis support the above results that skeletal-muscle-type alpha-actinin appears at the onset of fusion and that smooth-muscle-type alpha-actinin persists throughout the myogenesis. These results indicate (a) that the timing of expression of skeletal-muscle-type alpha-actinin is under regulation coordination with other major skeletal muscle proteins; (b) that, with respect to expression and distribution, skeletal-muscle-type alpha-actinin is closely related to alpha-actin, whereas smooth-muscle-type alpha- actinin is to gamma- and beta-actins; and (c) that skeletal- and smooth- muscle-type alpha-actinins have complementary distribution and do not co-exist in situ. 相似文献
42.
Summary When the red-light grown protonema ofAdiantum capillus-veneris was transferred to the dark, the nucleus ceased its migration ca. 5 hours before cell plate formation (Mineyuki andFuruya 1980). To see whether the nucleus was held by some cytoplasmic structure during nuclear positioning, protonemata were treated with various centrifugal forces at different stages of the cell cycle. Nuclei of G1 phase were easily displaced by centrifugation at 360×g for 15 minutes, but those of G2 or M phase were not displaced by it, suggesting that the nuclei were held by some cytoplasmic elements in G2 or M phase. This nuclear anchoring was not detectable in protonemata that were treated with 5mM colchicine. With this treatment, the nucleus did not stop its migration at late G2 and moved even in prophase. And the retardation of organelle movement which was observed in cytoplasm on the lateral side of the nucleus after the cessation of premitotic nuclear migration (Mineyuki andFuruya 1984) was not observed in the presence of colchicine. Thus the nuclei appear to be held by colchicine-sensitive structure in cytoplasm between the lateral surface of the nucleus and cell wall during the premitotic nuclear positioning. Electron micrographs showing cytoplasmic microtubules were consistent with the idea.Abbreviations PPN
Premitotic positioning of the nucleus
- L region
Cytoplasm between the lateral surface of the nucleus and cell wall (seeMineyuki
et al. 1984) 相似文献
43.
Coexistence of cardiac-type and fast skeletal-type myosin light chains in embryonic chicken cardiac muscle 总被引:4,自引:0,他引:4
Myosin from embryonic chicken ventricle contained a light chain component which comigrated with fast skeletal myosin light chain 1 (Lf1) on two dimensional electrophoresis in addition to cardiac type light chains (Lc1 and Lc2). Immunoblot analysis showed that this minor light chain band reacted with anti-Lf1 antibody. Antigens binding with anti-Lc1 and anti-Lf1 antibodies were located on myofibrils in embryonic cardiac muscle cells in vivo and in vitro. From these observations, we conclude that a small amount of Lf1 exists in embryonic chicken cardiac muscle. 相似文献
44.
Pairs of neurons were differentially stained by intracellular injection of the divalent cations, nickel and cobalt. Pairs of neuronal tracts could be similarly labelled following immersion of their axon bundles in the markers described. Use of nickel and a 4 : 6 mixture of cobalt and nickel according to the protocols presented here revealed the morphology of cricket neuron processes as thin as 1 μm in diameter and yielded a favourable contrast between the cells marked, as well as with respect to the background of unstained tissue. 相似文献
45.
Differentiation of myosin in chick embryos 总被引:14,自引:0,他引:14
46.
47.
The effect of an analog of LH-RH, (Des-Gly-NH210, Proethylamide9)-LH-RH, on LH release, was studied in one bull with azooapermia, and one cow with cystic follicle. The single intravenous injection of 100 μg LH-RH analog caused abrupt and marked increase in serum LH and the high levels of LH were maintained for 3 hours. The highest levels of serum LH were 48 and 114 times as high as the pre-treatment levels in a bull and a cow, respectively. Further studies are being undertaken to evaluate this compound for improving reproductive function in cattle. 相似文献
48.
Localization of 6S component of a alpha-actinin at Z-band 总被引:29,自引:0,他引:29
49.
Atrophy of the lymphoid tissues of mice induced by extracts of the submaxillary gland 总被引:2,自引:0,他引:2
50.