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31.
Ken-ichi Nakamura Naoshi Ishikawa Naotaka Izumiyama Junko Aida Mie Kuroiwa Naoki Hiraishi Mutsunori Fujiwara Atsushi Nakao Tadashi Kawakami Steven S.S. Poon Masaaki Matsuura Motoji Sawabe Tomio Arai Kaiyo Takubo 《Gene》2014
Trisomies 18 and 21 are genetic disorders in which cells possess an extra copy of each of the relevant chromosomes. Individuals with these disorders who survive birth generally have a shortened life expectancy. As telomeres are known to play an important role in the maintenance of genomic integrity by protecting the chromosomal ends, we conducted a study to determine whether there are differences in telomere length at birth between individuals with trisomy and diploidy, and between trisomic chromosomes and normal chromosomes. We examined samples of peripheral blood lymphocytes (PBLs) from 31 live neonates (diploidy: 10, trisomy 18: 10, trisomy 21: 11) and estimated the telomere length of each chromosome arm using Q-FISH. We observed that the telomeres of trisomic chromosomes were neither shorter nor longer than the mean telomere length of chromosomes as a whole among subjects with trisomies 18 and 21 (intra-cell comparison), and we were unable to conclude that there were differences in telomere length between 18 trisomy and diploid subjects, or between 21 trisomy and diploid subjects (inter-individual comparison). Although it has been reported that telomeres are shorter in older individuals with trisomy 21 and show accelerated telomere shortening with age, our data suggest that patients with trisomies 18 and 21 may have comparably sized telomeres. Therefore, it would be advisable for them to avoid lifestyle habits and characteristics such as obesity, cigarette smoking, chronic stress, and alcohol intake, which lead to marked telomere shortening. 相似文献
32.
The use of synthetic oligonucleotides and their analogs to block gene expression by binding the complementary RNA sequences in cells, the antisense principle, has been limited by poor uptake of the agents by cells in culture. This review describes attempts to harness by chemical conjugation the ability of certain peptides that may cross membranes to enhance the cellular uptake of oligonucleotides. These include fusogenic and hydrophobic peptides, nuclear localization signals, receptor targeting and translocating peptides, and various combinations. We also outline briefly some popular methods of peptide–oligonucleotide conjugation. Finally, we review the use of noncovalent peptide additives and the recent studies of conjugates of peptide nucleic acid (PNA) with peptides. 相似文献
33.
The preparation of the thymine peptide nucleicacid (PNA) monomer carrying a 2-nitrophenyl group in position4 is described. This monomer is incorporated into PNAoligomers and reacted with amines to yield PNA oligomerscarrying 5-methylcytosine derivatives. During thedeprotection-modification step two side reactions weredetected: degradation of PNA oligomer from the N-terminal residue and modification of N
4-tert-butylbenzoyl cytosine residue. Protection of the N-terminal position and the use of N
4-acetyl group for the protection of cytosine eliminate these side reactions. 相似文献
34.
刘黎 《分子细胞生物学报》1988,(3)
我们取视网膜基膜作为培养基底,证明了基膜能诱导和调节鸡胚视网膜神经纤维的生长,也可能影响纤维的生长方向。用抗层粘连蛋白的抗血清预先处理基膜,不能改变基膜上视网膜纤维生长的长度和图谱。PNA和抗PNA抗血清预先处理的基膜也不能改变纤维生长的长度,但却能改变生长图谱。神经氨酸酶预处理基膜能减少纤维生长长度。而轻度胰酶处理对纤维生长长度各有不同程度的降低。培养液中加入PNA(100微克/1毫升)24小时内能将视网膜纤维的生长图谱由直束式改变为网格式,其他凝集素(WGA,ConA)均未见这种作用。因此,基膜对纤维生长的作用很可能是多种分子综合作用的结果,其中PNA-受体也许起了重要作用。 相似文献
35.
To enhance understanding of how climate and humans influenced historical fire occurrence in the montane forests of Jasper National Park, we crossdated fire-scar and tree age samples from 172 plots. We tested effects of drought and climatic variation driven by the El Niño-Southern Oscillation (ENSO) and Pacific North American (PNA) pattern on fire occurrence. We also tested whether local droughts were associated with ENSO, PNA, Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation. We used a combination of instrumental and proxy-climate records to test whether climatic variation explained the absence of fire scars in our study area during the 20th century. From 1646 to 1915, 18 fires burned mainly during drier than average years. Drought years, but not fire years, were associated with positive ENSO and PNA indices, corresponding to warmer conditions with reduced snowpacks. Fire frequency varied through time, although no fire scars have formed since 1915. Potential recording trees present at all plots and climate conducive to fire over multiple years provide evidence that human influences superseded climatic variation to explain the lack of fire scars during the 20th century. Fire suppression significantly altered the fire regime after the formation of Jasper National Park, justifying the ongoing mechanical fuel treatments, prescribed and managed wildfires to improve forest resilience to climate change. 相似文献
36.
Leif Christensen Richard Fitzpatrick Brian Gildea Kenneth H. Petersen Henrik F. Hansen Troels Koch Michael Egholm Ole Buchardt Peter E. Nielsen James Coull Rolf H. Berg 《Journal of peptide science》1995,1(3):175-183
Peptide nucleic acids (PNA) were synthesized by a modified Merrifield method using several improvements. Activation by O-(benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate in combination with in situ neutralization of the resin allowed efficient coupling of all four Boc-protected PNA monomers within 30 min. HPLC analysis of the crude product obtained from a fully automated synthesis of the model PNA oligomer H-CGGACTAAGTCCATTGC-Gly-NH2, indicated an average yield per synthetic cycle of 97.1%. N1-benzyloxycarbonyl-N63-methylimidazole triflate substantially outperformed acetic anhydride as a capping reagent. The resin-bound PNAs were successfully cleaved by the ‘low–high’ trifluoromethanesulphonic acid procedure. 相似文献
37.
Isabelle Camby Thierry Janssen Robert De Decker Michel Petein Gil Raviv Jean-Lambert Pasteels Robert Kiss André Danguy 《In vitro cellular & developmental biology. Animal》1996,32(10):633-639
Summary While lectins are known to influence the cell growth of several types of normal and neoplastic tissues, their roles in the
case of prostatic cancer cells remain relatively unexplored. In the present work, we report thein vitro influence of five lectins, namely peanut (PNA), wheat germ (WGA), Concanavalin A (Con A),Griffonia simplicifolia (GSA-IA4), andPhaseolus vulgaris (PHA-L) agglutinins, on the cell proliferation of one androgen-sensitive (LNCaP) and two androgen-insensitive (PC-3 and DU
145) human prostatic cancer cell lines cultured in either 10% or 1% fetal bovine serum (FBS)-supplemented media. The cell
proliferation was assessed by means of the colorimetric 3-(4,5-dimethythiazol-2-yle)2,5-diphenyltetrazolium bromide. (MTT)
assay. Four lectin concentrations were tested (i.e., 0.1, 1, 10, and 100 μg/ml) at five experimental states (i.e., 2, 3, 5,
7, and 9 d following the addition of each lectin to the culture media). Our results demonstrated that the five lectins under
study had a globally significant dose-dependent toxic effect on prostatic cancer cell proliferation. Nevertheless, low doses
of GSA-IA4 and PHA-L significantly (P<0.05 toP<0.001) increased the cell proliferation of confluent PC-3 cells. Increasing the FBS from 1% to 10% in the culture media significantly
antagonized lectin-induced toxicity in the three prostatic cell lines. In conclusion, the present data strongly suggest that
some lectins might influence the proliferation of prostatic carcinoma cells. In addition, because lectins are present in our
diet, and are able to pass into the systemic circulation and thus reach the prostate, the present results suggest that some
lectins might exert an influence on prostate cancer growth under clinical conditions. 相似文献
38.
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40.
Peanut agglutinin (PNA) is a homotetrameric protein with a unique open quaternary structure. PNA shows non-two state profile
in chaotrope induced denaturation. It passes through a monomeric molten globule like state before complete denaturation (Reddyet al 1999). This denaturation profile is associated with the change in hydrodynamic radius of the native protein. Though the molten
globule-like state is monomeric in nature it expands in size due to partial denaturation. The size and shape of the native
PNA as well as the change in hydrodynamic radius of the protein during denaturation has been studied by dynamic light scattering
(DLS). The generation of two species is evident from the profile of hydrodynamic radii. This study also reveals the extent
of compactness of the intermediate state. 相似文献