全文获取类型
收费全文 | 98篇 |
免费 | 4篇 |
专业分类
102篇 |
出版年
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 5篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1964年 | 3篇 |
1962年 | 1篇 |
排序方式: 共有102条查询结果,搜索用时 8 毫秒
81.
Chromosome studies in the superfamily Bovoidea 总被引:1,自引:0,他引:1
The chromosome morphology of about 50 species of Bovoidea has now been investigated. Although the diploid number varies from 30 to 60 among these species, the fundamental number (NF) varies only (with but three exceptions) from 58 to 62. This indicates an almost exclusive use of the Robertsonian fusion mechanism of karyotype evolution in this group of species which represent 30 different genera. All known cytogenetic information on the Bovoidea has been summarized and a complete bibliography is presented for each species. Karyotypes and data on a number of previously unstudied species are presented. 相似文献
82.
Tissue from six human extragonadal teratomas was obtained for cytogenetic study. These included two gluteal lesions in infant females, and one each of thyroid, mediastinal, sacral and gastric teratomas in males. Tissue culture characteristics indicated tumor growth. All tumors, except the mediastinal lesion showed the presumed karyotype of its host, XX or XY. The mediastinal mass was tetraploid XXYY and contained an X chromatin body and double Y bodies. Our data support the concept that extragonadal teratomas in males and females arise mitotically from diploid cells and are more similar to identical twins. No heterosexual (XX) tumors were seen in males which would be expected in parthenogenetic tumors. The sex chromatin positive tumors seen in earlier studies may have resulted from polyploidy. Thus, male and female extragonadal teratomas have a different origin from the postmeiotic ovarian teratomas. 相似文献
83.
Prenatal diagnosis of trisomy 9. 总被引:1,自引:0,他引:1
A male karyotype with trisomy 9 (47,XY,+9) was identified in amniotic fluid cells from a 40-year-old pregnant woman. After termination of the pregnancy by saline abortion, the cytogenetic diagnosis was confirmed in a cell line grown from placental tissue. Microscopic and gross pathological findings in the fetus were compared to 1 case with trisomy 9 and 3 with trisomy 9 mosaicism reported in the literature. A distinct clinical syndrome appears to be associated with this rare autosomal trisomy. 相似文献
84.
85.
A model of the carbohydrate recognition domain CRD, residues 111-245, of
hamster galectin-3 has been made using homology modeling and dynamics
minimization methods. The model is based on the known x-ray structures of
bovine galectin-1 and human galectin-2. The oligosaccharides
NeuNAc-alpha2,3-Gal-beta1,4-Glc and GalNAc-alpha1, 3-
[Fuc-alpha1,2]-Gal-beta1,4-Glc, known to be specific high-affinity ligands
for galectin-3, as well as lactose recognized by all galectins were docked
in the galectin-3 CRD model structure and a minimized binding conformation
found in each case. These studies indicate a putative extended
carbohydrate-binding subsite in the hamster galectin- 3 involving Arg139,
Glu230, and Ser232 for NeuNAc-alpha2,3-; Arg139 and Glu160 for
fucose-alpha1,2-; and Arg139 and Ile141 for GalNAc-alpha1,3- substituents
on the primary galactose. Each of these positions is variable within the
whole galectin family. Two of these residues, Arg139 and Ser232, were
selected for mutagenesis to probe their importance in this newly identified
putative subsite. Residue 139 adopts main-chain dihedral angles
characteristic of an isolated bridge structural feature, while residue 232
is the C-terminal residue of beta- strand-11, and is followed immediately
by an inverse gamma-turn. A systematic series of mutant proteins have been
prepared to represent the residue variation present in the aligned
sequences of galectins-1, - 2, and -3. Minimized docked models were
generated for each mutant in complex with NeuNAc-alpha2,3-Gal-beta1,4-Glc,
GalNAc-alpha1, 3-[Fuc- alpha1,2]-Gal-beta1,4- Glc, and Gal-beta1,4-Glc.
Correlation of the computed protein-carbohydrate interaction energies for
each lectin- oligosaccharide pair with the experimentally determined
binding affinities for fetuin and asialofetuin or the relative potencies of
lactose and sialyllactose in inhibiting binding to asiolofetuin is
consistent with the postulated key importance of Arg139 in recognition of
the extended sialylated ligand.
相似文献
86.
Reassembly of flagellar B (alpha beta) tubulin into singlet microtubules: consequences for cytoplasmic microtubule structure and assembly 下载免费PDF全文
B(alpha beta) tubulin was obtained from a homogeneous class of microtubules, the incomplete B subfiber of sea urchin sperm flagellar doublet microtubules, by thermal fractionation. The thermally derived soluble B tubulin fraction (100, 000 g-h) repolymerizes in vitro, yielding microtubule-like structures. The microtubule-associated protein (MAP) composition and certain assembly parameters of thermally derived B tubulin are different from those reported for sonication- derived flageller tubulin and purified vertebrate tubulin. The "microtubules" reassembled from thermally prepared B tubulin are composed of 12-15 protofilaments (73% possess 14 protofilaments). A certain number possess a single "adlumenal component" applied to their inside walls, regardless of the number of protofilaments. Following the first cycle of polymerization, 81% of the B tubulin and essentially 100% of the MAPs remain cold insoluble. Evidence suggests that B tubulin assembles faithfully into a B lattice, creating a j seam between two protofilaments that are laterally bonded in a A-lattice configuration. The significance of these seams is discussed in relation to the mechanism of microtubule assembly, the stability of observed ribbons of protofilaments, and the three-dimensional organization of microtubule-associated components. 相似文献
87.
Java language has been demonstrated to be an effective tool in supporting medical image viewing in Russia. This evaluation was completed by obtaining a maximum of 20 images, depending on the client's computer workstation from one patient using a commercially available computer tomography (CT) scanner. The images were compared against standard CT images that were viewed at the site of capture. There was no appreciable difference. The client side is a lightweight component that provides an intuitive interface for end users. Each image is loaded in its own thread and the user can begin work after the first image has been loaded. This feature is especially useful on slow connection speed, 9.6 Kbps for example. The server side, which is implemented by the Java Servlet Engine works more effective than common gateway interface (CGI) programs do. Advantages of the Java Technology place this program on the next level of application development. This paper presents a unique application of Java in telemedicine. 相似文献
88.
Shaun A Tauck Jesse R Olsen Jarrod RC Wilkinson Riley J Wedlake Kathleen C Davis James G Berardinelli 《Reproductive biology and endocrinology : RB&E》2010,8(1):89
Background
The physiological mechanism by which bulls stimulate resumption of ovarian cycling activity in postpartum, anovular, suckled cows after calving may involve the concurrent activation of the hypothalamic-hypophyseal-ovarian (HPO) axis and hypothalamic-hypophyseal-adrenal (HPA) axis. Thus, the objectives of this experiment were to determine if characteristics of temporal patterns of cortisol and luteinizing hormone (LH) in postpartum, anovular, beef cows are influenced by acute exposure to bulls. The null hypotheses were that daily, temporal characteristics of cortisol and LH concentration patterns do not differ between cows exposed acutely to bulls or steers. 相似文献89.
90.