全文获取类型
收费全文 | 540篇 |
免费 | 42篇 |
出版年
2022年 | 3篇 |
2021年 | 15篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 18篇 |
2014年 | 29篇 |
2013年 | 24篇 |
2012年 | 39篇 |
2011年 | 24篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 29篇 |
2007年 | 32篇 |
2006年 | 31篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 13篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1969年 | 4篇 |
1968年 | 2篇 |
排序方式: 共有582条查询结果,搜索用时 984 毫秒
91.
G Lucotte M Kaminski 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(4):888-891
Polymorphism of plasma esterases in quail is very important. Phenotypic frequences of genetic variants of three esterases are examined and they show a high proportion of heterozygotes. The maintenance of this polymorphism is supposed to be due to the organophosphorus pesticides. 相似文献
92.
93.
Veith Weilnhammer Merve Fritsch Meera Chikermane Anna-Lena Eckert Katharina Kanthak Heiner Stuke Jakob Kaminski Philipp Sterzer 《Current biology : CB》2021,31(13):2868-2880.e8
- Download : Download high-res image (245KB)
- Download : Download full-size image
94.
Domestic dogs are skillful at using the human pointing gesture. In this study we investigated whether dogs take contextual information into account when following pointing gestures, specifically, whether they follow human pointing gestures more readily in the context in which food has been found previously. Also varied was the human''s tone of voice as either imperative or informative. Dogs were more sustained in their searching behavior in the ‘context’ condition as opposed to the ‘no context’ condition, suggesting that they do not simply follow a pointing gesture blindly but use previously acquired contextual information to inform their interpretation of that pointing gesture.Dogs also showed more sustained searching behavior when there was pointing than when there was not, suggesting that they expect to find a referent when they see a human point. Finally, dogs searched more in high-pitched informative trials as opposed to the low-pitched imperative trials, whereas in the latter dogs seemed more inclined to respond by sitting. These findings suggest that a dog''s response to a pointing gesture is flexible and depends on the context as well as the human''s tone of voice. 相似文献
95.
Heterosis in the codominance model: electrophoretic studies of proteins in the chicken-quail hybrid.
G Lucotte M Kaminski A Perramon 《Comparative biochemistry and physiology. B, Comparative biochemistry》1978,60(2):169-171
1. Electrophoretical comparisons was carried out on qualitative and quantitative differences of three proteins in the cock-quail hybrid: albumin, immunoglobulin and hemoglobin. All three components correspond to situations of codominance. 2. Heterosis was demonstrated twice: the immunological potentialities of the hybrid are increased by its possession of two types of Ig G; the affinity of hemoglobin for oxygen can be better regulated in the hybrid than in both parental species. 3. Proportions of the codominant parental components in the hybrid are different in the case of the three investigated proteins; this fact probably reflects the relative importance of the quantitative regulation of gene products in the hybrid. 相似文献
96.
Egg white proteins, hemoglobin, serum proteins and enzymes from Phasianus colchicus have been examined by starch gel electrophoresis. All three genetic parameters, mean proportion of loci polymorphic per population (P), mean numbers of alleles per locus (A), and mean proportion of loci heterozygous per individual (H), are given. Comparison were made between the proteins of the related species Coturnix coturnix japonica, and the variation of pheasant proteins is discussed in connexion with the genetic structure of the population studied. 相似文献
97.
98.
A large number of nucleoside analogues and 2′-deoxynucleoside triphosphates (dNTP) have been synthesized to interfere with DNA metabolism. However, in vivo the concentration and phosphorylation of these analogues are key limiting factors. In this context, we designed enzymes to switch nucleobases attached to a deoxyribose monophosphate. Active chimeras were made from two distantly related enzymes: a nucleoside deoxyribosyltransferase from lactobacilli and a 5′-monophosphate-2′-deoxyribonucleoside hydrolase from rat. Then their unprecedented activity was further extended to deoxyribose triphosphate, and in vitro biosyntheses could be successfully performed with several base analogues. These new enzymes provide new tools to synthesize dNTP analogues and to deliver them into cells. 相似文献
99.
Kamil Dobrzyn Nina Smolinska Marta Kiezun Karol Szeszko Edyta Rytelewska Katarzyna Kisielewska Marlena Gudelska Tadeusz Kaminski 《Acta veterinaria Scandinavica》2018,60(1):76
Background
Orexin A (OXA) and orexin B (OXB) are hypothalamic-derived peptides that participate in the regulation of energy metabolism, food intake and reproductive function by influencing the hypothalamic-pituitary-ovarian axis. Orexins are also produced in the endometrium, myometrium and placenta, which suggests that they could act as a link between energy metabolism and the reproductive system. Changes in the expression of orexin and the orexin receptor genes and proteins during the oestrous cycle and early gestation in pigs imply that orexin activity may be regulated by local factors within the uterus. The aim of this study was to investigate the influence of progesterone (P4) on the expression of orexin system genes, and proteins in the porcine uterus during early gestation. Gene expression was analyzed by real-time PCR. Adiponectin secretion was determined by ELISA, and the receptors proteins content was defined using western blot analysis.Results
In the endometrium, P4 enhanced OXA secretion on days 10 to 11 of gestation and OXB secretion on days 12 to 13. In the myometrium, P4 inhibited the secretion of both orexins on days 15 to 16 and OXB secretion also on days 12 to 13. In the endometrium, P4 inhibited the expression of orexin receptor 1 (OX1R) protein at nearly all times analyzed, whereas the expression of orexin receptor 2 (OX2R) protein was inhibited only on days 15 to 16 of gestation. In the myometrium, P4 stimulated OX1R protein expression on days 12 to 13 and 15 to 16 of gestation and inhibited OX1R protein expression on days 27 to 28. The expression of OX2R protein in the myometrium increased on days 12 to 13 and decreased on days 10 to 11 and 15 to 16.Conclusions
The results indicate that P4 could regulate the expression of the orexin system in the porcine uterus during early pregnancy, which suggests the presence of a local feedback loop that could play an important role in the regulation of maternal metabolism during pregnancy. The findings may contribute to the existing knowledge of the mechanisms linking maternal energy metabolism with the regulation of the reproductive system during pregnancy.100.
L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three
loci in all vertebrates examined, with the exception of lampreys, which
have a single LDH locus. Biochemical characterizations of LDH proteins have
suggested that a gene duplication early in vertebrate evolution gave rise
to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of
lineages more recently. Although some phylogenetic studies of LDH protein
sequences have supported this pattern of gene duplication, others have
contradicted it. In particular, a number of studies have suggested that
Ldh-C represents the earliest divergence among vertebrate LDHs and that it
may have diverged from the other loci well before the origin of
vertebrates. Such hypotheses make explicit statements about the
relationship of vertebrate and invertebrate LDHs, but to date, no closely
related invertebrate LDH sequences have been available for comparison. We
have attempted to provide further data on the timing of gene duplications
leading to multiple vertebrate LDHs by determining the cDNA sequence of the
LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other
LDH sequences provide strong support for the duplications giving rise to
multiple vertebrate LDHs having occurred after vertebrates diverged from
tunicates. The timing of these LDH duplications is consistent with data
from a number of other gene families suggesting widespread gene duplication
near the origin of vertebrates. With respect to the relationships among
vertebrate LDHs, our data are not consistent with previous claims that
Ldh-C represented the earliest divergence. However, the precise
relationships among some of the main lineages of vertebrate LDHs were not
resolved in our analyses.
相似文献