全文获取类型
收费全文 | 211篇 |
免费 | 15篇 |
专业分类
226篇 |
出版年
2020年 | 6篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 17篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 6篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1961年 | 3篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有226条查询结果,搜索用时 0 毫秒
1.
Although the central and stable position of female rhesus monkeys in semi-free-ranging bands has been observed and described, the position of the developing male in the social group is not as well delineated. The present study is an attempt to describe interactions of 18 males with members of their families. Quantitative observations were made on one band (E) of rhesus monkeys on Cayo Santiago. Incidences of behavior recorded were joining, grooming, and threatening. The resulting data were analyzed by comparing the behavior of the males studied toward members of their genealogy as well as unrelated members of the social group. Behavior of family and non-relatives toward the males was also revealed. Statistical analysis revealed that the male subjects engaged in more positive social interactions within the matrifocal family than with other members of the genealogy, and in turn, more such behavior was observed within the genealogy than with unrelated monkeys. Threatening behavior within the genealogies was infrequent. Age effects were noted in that family members directed more interactions toward younger males and as males matured, they groomed more but joined family members less frequently. These data suggest mechanisms of socialization within the genealogy that may be different from those employed within the unrelated social group. 相似文献
2.
3.
4.
A new simple mouse assay for the in vivo evaluation of CCK antagonists which is based upon visual determination of the gastric emptying of a charcoal meal is described. CCK-8 (24 micrograms/kg s.c.) but not various other peptide and nonpeptide agents effectively inhibited gastric emptying in this test system. The effect of CCK-8 was antagonized by established peripheral CCK antagonists but not representative agents of various other pharmacological classes. The rank order of potency of the CCK antagonists were: L-364,718 (ED50 = 0.01 mg/kg, i.v.; 0.04 mg/kg, p.o.) greater than Compound 16 (ED50 = 1.5 mg/kg, i.v.; 2.0 mg/kg p.o.) greater than asperlicin (ED50 = 14.8 mg/kg i.v.) greater than proglumide (ED50 = 184 mg/kg i.v.; 890 mg/kg, p.o.). Duration of action studies based upon ED50 values determined at various time intervals after oral administration showed that L-364,718 and proglumide are considerably longer acting than Compound 16. Asperlicin (ED50 greater than 300 mg/kg, p.o.) was ineffective as a CCK antagonist when administered orally. These data provide the first direct comparisons of the in vivo potencies of current CCK antagonists and demonstrate the utility of a new simple mouse assay for the in vivo characterization of peripheral CCK antagonists. 相似文献
5.
The influence of the systemic fungicides propiconazole (Tilt 250E) and carbendazim (Bavistin) at field application rates
on the functioning of three arbuscular mycorrhizal fungi was studied. Short-term fungal 32P transport and succinate dehydrogenase (SDH) activity in external hyphae of Glomus intraradices Schenck and Smith, G. claroideum Schenck and Smith and G. invermaium Hall in symbiosis with pea (Pisum sativum L.) were measured. In the experimental system used, the hyphae grew into two root-free hyphal compartments (HCs). The fungicides
were applied to each HC 24 days after sowing and 32P was added to one HC of each pot. Four days later, the fungicide effect on fungal P transport was measured as the difference
in 32P content of treated and untreated plants. SDH activity in fungal hyphae was determined in the HCs given no 32P. Carbendazim severely inhibited 32P transport and SDH activity in external hyphae at an application rate of 0.5 μg g–1 soil. The ergosterol inhibitor propiconazole affected none of these parameters. The fungicides had similar effects on all
three fungal species, although P transport efficiency and SDH activity differed markedly between the fungi.
Accepted: 12 December 1996 相似文献
6.
Cell culture studies on neurofibromatosis (von Recklinghausen). II. Occurrence of glial cells in primary cultures of peripheral neurofibromas 总被引:4,自引:1,他引:3
The occurrence of glial cells in primary cultures established from peripheral neurofibromas of 18 patients with neurofibromatosis (von Recklinghausen) is described. The spindle-shaped cells can be distinguished from fibroblasts on the basis of morphological and ultrastructural criteria. As demonstrated by immunocytochemical analysis, the spindle cells express S-100 protein. Neither glial fibrillar acidic protein nor myelin basic protein can be detected in these cells. In many respects the spindle cells resemble immature Schwann cells in culture. 相似文献
7.
Pre- and postsynaptic adrenergic activation by norepinephrine reuptake inhibitors in the field-stimulated rat vas deferens 总被引:2,自引:0,他引:2
Desipramine (DMI), protriptyline, chlorpromazine, amitriptyline and cocaine, alone or in the presence of prazosin, produced a dose-related inhibition of contractions induced by field stimulation of the rat vas deferens. The inhibition of contractions was readily reversed by yohimbine. In contrast, when yohimbine was first added to the bath, all agents, except chlorpromazine, produced a dose-related enhancement of contractions which were readily reversed by prazosin. The potencies of these agents for induction of contractile inhibition, after prazosin, and contractile enhancement, after yohimbine, were similar. Both of the latter contractile responses of DMI were markedly attenuated or absent in tissues taken from rats pretreated with reserpine and alpha-methyl-para-tyrosine. The data indicate that, in the rat vas deferens, inhibition of norepinephrine reuptake results primarily in presynaptic (α2) receptor activation. Postsynaptic (α1) adrenergic activation by inhibition of norepinephrine reuptake can be demonstrated in this tissue only after presynaptic (α2) receptor blockade. The possible implications of the present studies to the delayed clinical onset of action of tricyclic antidepressants is discussed. 相似文献
8.
9.