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991.
The intracellular signaling pathways mediating the nuclear exclusion of the androgen receptor (AR) by melatonin were evaluated
in PC3 cells stably transfected with the AR. The melatonin-induced nuclear exclusion of the AR by melatonin (100 nM, 3 h)
was blocked by LY 83583 (an inhibitor of guanylyl cyclases). 8-Bromo-cGMP (a cell-permeable cGMP analog), mimicked the effect
of melatonin, as did ionomycin (a calcium ionophore) and PMA [an activator of protein kinase C (PKC)], and their effects were
blocked by GF-109203X (a selective PKC inhibitor). BAPTA (an intracellular calcium chelator) blocked the effects of melatonin
and 8-bromo-cGMP but not of PMA. Inhibition or activation of the protein kinase A pathway did not affect basal or melatonin-mediated
AR localization. We conclude that the melatonin-mediated rise in cGMP elicits AR nuclear exclusion via a pathway involving
increased intracellular calcium and PKC activation. These results define a novel signaling pathway that regulates AR localization
and androgen responses in target cells.
Received 31 July 2001; received after revision 18 September 2001; accepted 30 October 2001 相似文献
992.
D.T.A. Lamport 《Cellular and molecular life sciences : CMLS》2001,58(10):1363-1385
This review of the living cell wall [1] and its protein components is in two parts. The first is anecdotal. A personal account
spanning over 40 years research may perhaps be an antidote to one stereotypical view of scientists as detached and humorless.
The second part deals with the meaning of function, particularly as it applies to hydroxyproline-rich glycoproteins. Function
is a difficult word to define objectively. However, with help from such luminaries as Humpty Dumpty: "A word means what I
want it to mean, neither more nor less," and Wittgenstein: "Giving examples of usage ... is the only way to talk about meaning,"
it is possible to construct a ziggurat representing increasingly complex levels of organization from molecular structure to
ecology. Forty years ago I suggested that hydroxyproline-rich structural proteins played a key role in cell wall functioning.
But because the bulk of the wall is carbohydrate, there has been an understandable resistance to paradigm change. Expansins,
paradoxically, contribute greatly to this resistance because their modus operandi as cell-wall-loosening proteins is based
on the idea that they break hydrogen bonds between polysaccharide chains allowing slippage. However, this view is not consistent
with the recent discovery [Grobe et al. (1999) Eur. J. Biochem 263: 33-40] that β-expansins may be proteases, as it implies that the extensin network is not a straightjacket but a substrate for expansin
in muro. Such a direct role for extensins in both negative and positive regulation of cell expansion and elongation may constitute
a major morphogenetic mechanism operating at all levels of plant growth and development. 相似文献
993.
Mechanisms of self-incompatibility in flowering plants 总被引:14,自引:0,他引:14
Self-incompatibility is a widespread mechanism in flowering plants that prevents inbreeding and promotes outcrossing. The
self-incompatibility response is genetically controlled by one or more multi-allelic loci, and relies on a series of complex
cellular interactions between the self-incompatible pollen and pistil. Although self-incompatibility functions ultimately
to prevent self-fertilization, flowering plants have evolved several unique mechanisms for rejecting the self-incompatible
pollen. The self-incompatibility system in the Solanaceae makes use of a multi-allelic RNase in the pistil to block incompatible pollen tube growth. In contrast, the Papaveraceae system appears to have complex cellular responses such as calcium fluxes, actin rearrangements, and programmed cell death
occurring in the incompatible pollen tube. Finally, the Brassicaceae system has a receptor kinase signalling pathway activated in the pistil leading to pollen rejection. This review highlights
the recent advances made towards understanding the cellular mechanisms involved in these self-incompatibility systems and
discusses the striking differences between these systems.
Received 10 May 2001; received after revision 20 June 2001; accepted 20 June 2001 相似文献
994.
995.
灰色关联分析在大麦种质综合评价上的应用 总被引:2,自引:2,他引:0
李绥艳 《农业系统科学与综合研究》2001,17(2):118-118,121
应用灰色关联分析法对高蛋白大麦种质进行综合评价,结果表明,该方法简单易行、结果全面、客观。 相似文献
996.
T. Nakaki B. C. Wise D. M. Chuang R. Kato 《Cellular and molecular life sciences : CMLS》1989,45(9):879-881
Summary The effects of serotonin on the formation of inositol phosphates and protein phosphorylation were examined in cultured smooth muscle cells. Serotonin stimulated the formation of [3H]inositol monophosphate, [3H]inositol bisphosphate and [3H]inositol trisphosphate. This effect was prevented by 5-HT2 specific antagonist, 6-methyl-1-(1-methylethyl)ergoline-8-carboxylic acid, 2-hydroxy-1-methylpropyl ester [Z]-2-butenedioate (LY53857). Serotonin stimulated the phosphorylation of many polypeptides, among which a 20 kDa polypeptide was the most prominent. The phosphorylation was also inhibited by LY53857. LY53857 alone produced no effects on protein phosphorylation. The 20 kDa polypeptides were also phosphorylated by the addition of 12-O-tetradecanoylphorbol-13-acetate. These results suggest that serotonin stimulates protein phosphorylation through 5-HT2 receptors and possibly activates protein kinase C in intact vascular smooth muscle cells.Part of the data contained in this paper was presented at the 74th local meeting of the Japanese Society of Pharmacology at Kanagawa. 相似文献
997.
一个犬凝集素基因VIP36的人类同源基因cDNA的克隆、染色体定位和表达谱分析 总被引:10,自引:10,他引:0
从人的胎脑cDNA文库中克隆到一条犬凝集素基因VIP36的人类同源基因,此cDNA序列全长2430bp,拟编码一个382个氨基酸残基的蛋白,它编码的蛋白与犬VIP36有52%的同源性,因此将其命名为人类VIP36L基因,应用辐射杂交方法,钭该基因定位在人2号染色体的分子标记D2S388和D2S113之间,采用基因芯片杂交的方法研究其表达谱情况,发现该基因在胎皮和肝癌组织中表达量较高。 相似文献
998.
绿色荧光蛋白基因mgfp4在水稻愈伤组织中的瞬时表达 总被引:10,自引:0,他引:10
采用基因枪方法将适用于高等植物的绿色荧光蛋白基因mgfp4转化到水稻愈伤组织之中,获得高效瞬时表达,在荧光显微镜和激光共聚焦显微镜下观察到强烈绿色荧光。绿色荧光蛋白mGFP4生色团形成迅速,转化4h后就能观察到绿色荧光,并且持续时间较长,2d后才基本消退。 相似文献
999.
Neurodegeneration changes in primary central nervous system neurons transfected with the Alzheimer-associated neuronal thread protein gene 总被引:6,自引:0,他引:6
The AD7c-NTP gene is over-expressed in brains with Alzheimer's disease (AD), and increased levels of the corresponding protein
are detectable in cortical neurons, brain tissue extracts, cerebrospinal fluid, and urine beginning early in the course of
AD neurodegeneration. In the present study, we utilized a novel method to transfect post-mitotic primary neuronal cell cultures,
and demonstrated that over-expression of the AD7c-NTP gene causes cell death and neuritic sprouting, two prominent abnormalities
associated with AD. These results provide further evidence that aberrantly increas-ed AD7c-NTP expression may have a role
in AD-type neurodegeneration. In addition, we demonstrate that primary post-mitotic neurons can be efficiently transfected
with conventional recombinant plasmid DNA to evaluate the effects of gene over-expression in relevant in vitro models.
Received 31 January 2001; received after revision 31 March 2001; accepted 4 April 2001 相似文献
1000.
本文通过试验证明,水解时间影响水解度和蛋白回收率.进一步从凝胶色谱分析中可以看出,肽分子的分布是连续的。随着水解时间的延长,水解程度提高,小肽分子的数量增多。 相似文献