全文获取类型
收费全文 | 199篇 |
免费 | 20篇 |
国内免费 | 1篇 |
出版年
2021年 | 5篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 8篇 |
2009年 | 16篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 2篇 |
1963年 | 1篇 |
排序方式: 共有220条查询结果,搜索用时 171 毫秒
1.
Continuous intravenous infusion of oxytocin (3 micrograms/h) between Days 13 and 21 after oestrus delayed return to oestrus by 7 days (length of cycle 23.3 +/- 0.6 days compared to 16.6 +/- 0.2 days in control ewes). At a lower infusion rate (0.3 micrograms/h) oxytocin delayed luteolysis in only 2 of 5 ewes. Treatment from Day 14, when luteolysis had already begun, was ineffective. Delay of luteal regression by oxytocin had no effect on the length of subsequent cycles. Measurement of circulating progesterone concentrations and luteal weight showed that prolongation of the oestrous cycle was due to prevention of luteal regression. Luteal regression and behavioural oestrus were induced during continuous oxytocin administration begun on Day 13 when cloprostenol was given on Day 15 (mean cycle length, 17.3 +/- 0.21 days). Continuous oxytocin infusion from Day 13 blocked the rise in uterine oxytocin receptor concentrations which normally precedes oestrus. Mean receptor concentrations in caruncular and intercaruncular endometrium and in myometrium were 76, 36 and 9 fmol/mg protein on Day 17 in ewes receiving continuous oxytocin (3 micrograms/h); in control ewes these values were 675, 638 and 130 fmol/mg protein respectively at oestrus. Receptor concentrations on the day of oestrus in ewes receiving oxytocin and cloprostenol were not significantly different from those in control ewes (649, 852, and 109 fmol/mg protein respectively). Since cloprostenol, a PGF-2 alpha analogue, overcame the antiluteolytic action of oxytocin, it is suggested that continuous oxytocin treatment may inhibit uterine production of PGF-2 alpha, possibly by down regulating the uterine oxytocin receptor.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
2.
Genome structure and virion polypeptides of the primate herpesviruses Herpesvirus aotus types 1 and 3: comparison with human cytomegalovirus. 总被引:7,自引:5,他引:2 下载免费PDF全文
A Ebeling G Keil B Nowak B Fleckenstein N Berthelot P Sheldrick 《Journal of virology》1983,45(2):715-726
Two serologically distinguishable primate herpesviruses, Herpesvirus aotus type 1 and type 3, were examined with regard to their genomes and structural polypeptides. The duplex DNA genomes of these two viruses were found to be essentially identical in molecular weight (Mr approximately equal to 145 X 10(6)) and guanine plus cytosine composition (55%). Both contained unique and inverted repeat nucleotide sequences of the same size and arrangement, which, as judged by DNA-DNA hybridization and restriction enzyme analyses, were at least 95% homologous. In addition, no differences were observed in electrophoretic profiles of virion polypeptides. Because of their great similarity with respect to these criteria, the two viruses ought to be considered independent isolates (or strains) of a single virus, which should be designated H. aotus type 1. The elevated molecular weight and presence of two sets of inverted repeat sequences closely resemble the structure of the human cytomegalovirus genome. However, no sequence homology (less than 5%) nor similarity in virion polypeptides was detected between H. aotus type 1 and human cytomegalovirus. 相似文献
3.
4.
1. An ALGOL computer programme is presented for the calculation of the results of amino acid analysis. 2. The suggestion is made that a similar approach could be made to other tedious and repetitive biochemical calculations. 相似文献
5.
The rad16 gene of Schizosaccharomyces pombe: a homolog of the RAD1 gene of Saccharomyces cerevisiae. 总被引:6,自引:2,他引:4 下载免费PDF全文
A M Carr H Schmidt S Kirchhoff W J Muriel K S Sheldrick D J Griffiths C N Basmacioglu S Subramani M Clegg A Nasim et al. 《Molecular and cellular biology》1994,14(3):2029-2040
The rad10, rad16, rad20, and swi9 mutants of the fission yeast Schizosaccharomyces pombe, isolated by their radiation sensitivity or abnormal mating-type switching, have been shown previously to be allelic. We have cloned DNA correcting the UV sensitivity or mating-type switching phenotype of these mutants and shown that the correcting DNA is encompassed in a single open reading frame. The gene, which we will refer to as rad16, is approximately 3 kb in length, contains seven introns, and encodes a protein of 892 amino acids. It is not essential for viability of S. pombe. The predicted protein is the homolog of the Saccharomyces cerevisiae RAD1 protein, which is involved in an early step in excision-repair of UV damage from DNA. The approximately 30% sequence identity between the predicted proteins from the two yeasts is distributed throughout the protein. Two-hybrid experiments indicate a strong protein-protein interaction between the products of the rad16 and swi10 genes of S. pombe, which mirrors that reported for RAD1 and RAD10 in S. cerevisiae. We have identified the mutations in the four alleles of rad16. They mapped to the N-terminal (rad10), central (rad20), and C-terminal (rad16 and swi9) regions. The rad10 and rad20 mutations are in the splice donor sequences of introns 2 and 4, respectively. The plasmid correcting the UV sensitivity of the rad20 mutation was missing the sequence corresponding to the 335 N-terminal amino acids of the predicted protein. Neither smaller nor larger truncations were, however, able to correct its UV sensitivity. 相似文献
6.
Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews
(genus Sorex) for the region between the tRNA(Pro) and the conserved
sequence block-F revealed variable numbers of 79-bp tandem repeats. These
repeats were found in all 19 individuals sequenced, representing three
subspecies and one closely related species of the masked shrew group (Sorex
cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an
outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an
adjacent 76-bp imperfect copy of the tandem repeats. One individual was
heteroplasmic for length variants consisting of five and seven copies of
the 79-bp tandem repeat. The sequence of the repeats is conducive to the
formation of secondary structure. A termination-associated sequence is
present in each of the repeats and in a unique sequence region 5' to the
tandem array as well. Mean genetic distance between the masked shrew taxa
and the pygmy shrew was calculated separately for the unique sequence
region, one of the tandem repeats, the imperfect repeat, and these three
regions combined. The unique sequence region evolved more rapidly than the
tandem repeats or the imperfect repeat. The small genetic distance between
pairs of tandem repeats within an individual is consistent with a model of
concerted evolution. Repeats are apparently duplicated and lost at a high
rate, which tends to homogenize the tandem array. The rate of D- loop
sequence divergence between the masked and pygmy shrews is estimated to be
15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid
sequence evolution in shrews may be due either to their high metabolic rate
and short generation time or to the presence of variable numbers of tandem
repeats.
相似文献
7.
8.
大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育 总被引:1,自引:0,他引:1
本实验用免疫组织化学ABC法研究了大鼠胼胝体内神经肽Y免疫反应阳性(NPY-IR)纤维的生后发育。结果发现,许多NPY-IR纤维在大鼠出生时便存在于胼胝体内。NPY-IR胼胝体纤维的密度在生后1周内继续逐渐增高,在第2周内达到最高峰。之后,NPY-IR胼胝体纤维的密度逐渐下降,至第3周末时接近成年时的水平,即仅有少量NPY-IR纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多NPY-IR胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。 相似文献
9.
Measurements of venoarterial concentration differences across the ovary in anesthetized sheep have demonstrated that the ovary secretes ovine neurophysin I/II (oNP I/II) and that this process is stimulated by the prostaglandin F2 alpha analogue, cloprostenol. A parallel increase in the secretion of oxytocin (OT) was observed in response to cloprostenol, and the mean molar ratio of oNP I/II to OT secreted was 1.2. There was no detectable ovarian secretion of oNP III. Secretion of oNP I/II and OT was absent after hysterectomy. The data support other evidence indicating that the corpus luteum synthesizes OT, and confirm that the neurophysin associated with OT in the sheep is oNP I/II. 相似文献
10.