全文获取类型
收费全文 | 1943篇 |
免费 | 9篇 |
国内免费 | 17篇 |
专业分类
系统科学 | 9篇 |
丛书文集 | 16篇 |
教育与普及 | 1篇 |
理论与方法论 | 7篇 |
现状及发展 | 877篇 |
研究方法 | 58篇 |
综合类 | 997篇 |
自然研究 | 4篇 |
出版年
2012年 | 28篇 |
2011年 | 28篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 35篇 |
2007年 | 39篇 |
2006年 | 41篇 |
2005年 | 67篇 |
2004年 | 78篇 |
2003年 | 36篇 |
2002年 | 26篇 |
2001年 | 56篇 |
2000年 | 55篇 |
1999年 | 57篇 |
1996年 | 10篇 |
1994年 | 259篇 |
1992年 | 37篇 |
1991年 | 21篇 |
1990年 | 35篇 |
1989年 | 33篇 |
1988年 | 34篇 |
1987年 | 31篇 |
1986年 | 29篇 |
1985年 | 44篇 |
1984年 | 29篇 |
1983年 | 18篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 27篇 |
1979年 | 60篇 |
1978年 | 23篇 |
1977年 | 38篇 |
1976年 | 28篇 |
1975年 | 28篇 |
1974年 | 38篇 |
1973年 | 43篇 |
1972年 | 43篇 |
1971年 | 42篇 |
1970年 | 39篇 |
1969年 | 38篇 |
1968年 | 42篇 |
1967年 | 46篇 |
1966年 | 30篇 |
1965年 | 21篇 |
1964年 | 18篇 |
1959年 | 14篇 |
1958年 | 16篇 |
1957年 | 17篇 |
1956年 | 12篇 |
1955年 | 13篇 |
排序方式: 共有1969条查询结果,搜索用时 46 毫秒
191.
The sponge Dysidea herbacea (Keller) was found to possess hemagglutinins. The major component, DHA-I, is a protein with a mol. wt of 26,000, which dissociates into subunits of equal size (14,000). It contains large amounts of glutamic acid and aspartic acid residues, but no half-cystine, methionine or histidine residues. DHA-I reacted with rabbit and human AB0 erythrocytes. D-galactose and lactose were effective inhibitors of DHA-I. The sponge also contained a minor component(s) which reacted preferentially with rabbit erythrocytes but not with human AB0 erythrocytes. 相似文献
192.
193.
194.
The atrial and ventricular myosin light chains of human, monkey and sheep hearts were compared by dodecylsulfate polyacrylamide gel electrophoresis. The atrial light chain 2 and ventricular light chain 2 are similar among these mammals. However, the atrial light chain 1 of monkey has different electrophoretic mobility from those of human and sheep. The monkey ventricular light chain 1 has same mobility as that of sheep but different from that of human. 相似文献
195.
196.
Light-dependent antibody labelling of photoreceptors 总被引:1,自引:0,他引:1
Monoclonal antibodies are tools widely used to analyse the structure of the nervous system. Whereas some labelling patterns are highly reproducible, others appear to vary from one preparation to the next, as we noticed in particular for some antibodies with respect to photoreceptor labelling. To establish whether some of this variability can be linked to functional criteria, we tested for light-dependence. We found two antibodies that label photoreceptor outer segments, only when the retina has been illuminated, and a third antibody that has a selective affinity for dark-adapted outer segments. The two antibodies against light-activated sites are primarily directed against the highly phosphorylated neurofilament subunit at relative molecular mass 200,000 (200K). One of them, RT97, recognizes on immunoblots, in addition to neurofilaments, a light-activated epitope on a protein that resembles the photopigment rhodopsin, presumably a phosphorylation-dependent site. Antibodies like those described here may allow the study of physiological processes such as light and dark adaptation using morphological techniques. 相似文献
197.
198.
Mild acidic treatment increases the rheumatoid factor titre of some sera and synovial fluids (SF) in rheumatoid arthritis (RA), juvenile RA (JRA) and most frequently in rheumatoid vasculitis. This unmasking of 'hidden' RF in serum and SF samples correlated with the RF-immune complexes (RF-IC) and complexed C4 present in the 3% polyethylene glycol (PEG) precipitates, indicating that by means of 'hidden' RF measurements RF-ICs are possibly detected. This method seems to provide a diagnostic tool for detecting RF-ICs in RA and other related diseases. 相似文献
199.
Penfluridol, a neuroleptic with diphenylbutyl piperidine structure, blocked the dopamine-sensitive adenylate cyclase in homogenates of corpus striatum and substantia nigra of rats, probably by a competitive antagonism versus dopamine. 相似文献
200.