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931.
Sun Mi Shin Kyu Suk Cho Min Sik Choi Sung Hoon Lee Seol-Heui Han Young-Sun Kang Hee Jin Kim Jae Hoon Cheong Chan Young Shin Kwang Ho Ko 《Neurochemical research》2010,35(7):976-985
In response to brain injury, microglia migrate and accumulate in the affected sites, which is an important step in the regulation
of inflammation and neuronal degeneration/regeneration. In this study, we investigated the effect of urokinase-type plasminogen
activator (uPA) on the BV-2 microglial cell migration. At resting state, BV-2 microglial cells secreted uPA and the release
of uPA was increased by ATP, a chemoattractant released from injured neuron. The migration of BV-2 cell was significantly
induced by uPA and inhibited by uPA inhibitors. In this condition, uPA increased the activity of matrix metalloproteinase
(MMP-9) and the inhibition of MMP activity with pharmacological inhibitors against either uPA (amiloride) or MMP (phenanthrolene
and SB-3CT) effectively prevented BV2 cell migration. Interestingly, the level of MMP-9 protein and mRNA in the cell were
not changed by uPA. These results suggest that the increase of MMP-9 activity by uPA is regulated at the post-translational
level, possibly via increased activation of the enzyme. Unlike the uPA inhibitor, plasmin inhibitor PAI-1 only partially inhibited
uPA-induced cell migration and MMP-9 activation. The incubation of recombinant MMP-9 with uPA resulted in the activation of
MMP-9. These results suggest that uPA plays a critical role in BV-2 microglial cell migration by activating pro-MMP-9, in
part by its direct action on MMP-9 and also in part by the activation of plasminogen/plasmin cascade. 相似文献
932.
Jung Eun Hwang Joon Ki Hong Chan Ju Lim Huan Chen Jihyun Je Kyung Ae Yang Dool Yi Kim Young Ju Choi Sang Yeol Lee Chae Oh Lim 《Plant cell reports》2010,29(8):905-915
The phytocystatins of plants are members of the cystatin superfamily of proteins, which are potent inhibitors of cysteine
proteases. The Arabidopsis genome encodes seven phytocystatin isoforms (AtCYSs) in two distantly related AtCYS gene clusters. We selected AtCYS1 and AtCYS2 as representatives for each cluster and then generated transgenic plants expressing the GUS reporter gene under the control of each gene promoter. These plants were used to examine AtCYS expression at various stages of plant development and in response to abiotic stresses. Histochemical analysis of AtCYS1 promoter- and AtCYS2 promoter-GUS transgenic plants revealed that these genes have similar but distinct spatial and temporal expression patterns
during normal development. In particular, AtCYS1 was preferentially expressed in the vascular tissue of all organs, whereas AtCYS2 was expressed in trichomes and guard cells in young leaves, caps of roots, and in connecting regions of the immature anthers
and filaments and the style and stigma in flowers. In addition, each AtCYS gene has a unique expression profile during abiotic stresses. High temperature and wounding stress enhanced the expression
of both AtCYS1 and AtCYS2, but the temporal and spatial patterns of induction differed. From these data, we propose that these two AtCYS genes play important, but distinct, roles in plant development and stress responses. 相似文献
933.
Deepa Alex Emilia Conceição Leong Zai‐Jun Zhang Gloria Tse Ho Yan Shuk‐Han Cheng Chi‐Weng Leong Zhen‐Hua Li Kai‐Heng Lam Shun‐Wan Chan Simon Ming‐Yuen Lee 《Journal of cellular biochemistry》2010,109(2):339-346
Angiogenesis plays an important role in the development of neoplastic diseases such as cancer. Resveratrol and its derivatives exert antiangiogenic effects, but the mechanisms of their actions remain unclear. The aim of this study was to evaluate the antiangiogenic activity of resveratrol and its derivative trans‐3,5,4′‐trimethoxystilbene in vitro using human umbilical vein endothelial cells (HUVECs) and in vivo using transgenic zebrafish, and to clarify their mechanisms of action in zebrafish by gene expression analysis of the vascular endothelial growth factor (VEGF) receptor (VEGFR2/KDR) and cell‐cycle analysis. trans‐3,5,4′‐Trimethoxystilbene showed significantly more potent antiangiogenic activity than that of resveratrol in both assays. In zebrafish, trans‐3,5,4′‐trimethoxystilbene caused intersegmental vessel regression and downregulated VEGFR2 mRNA expression. Trans‐3,5,4′‐trimethoxystilbene also induced G2/M cell‐cycle arrest, most specifically in endothelial cells of zebrafish embryos. We propose that the antiangiogenic and vascular‐targeting activities of trans‐3,5,4′‐trimethoxystilbene result from the downregulation of VEGFR2 expression and cell‐cycle arrest at G2/M phase. J. Cell. Biochem. 109: 339–346, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
934.
Oh Yeun Kwon Kyounghee Hwang Jeom‐A Kim Kwangmyung Kim Ick Chan Kwon Hyun Kyu Song Hyesung Jeon 《Journal of cellular biochemistry》2010,111(2):508-519
Fe65 and Dab1 are adaptor proteins that interact with the cytoplasmic domain of amyloid precursor protein (APP) via phosphotyrosine‐binding (PTB) domain and that affect APP processing and Aβ production. Co‐expression of Dab1 with Fe65 and APP resumed nuclear translocation of Fe65 despite of its cytoplasmic anchor, APP. The decreased amount of Fe65 bound to APP was shown in co‐immunoprecipitation assay from the cells with Dab1 which also displayed the effect on APP processing. These data suggested that Fe65 and Dab1 compete for binding to APP. Surprisingly, we found that Fe65 interacts with Dab1 via C‐terminal region of Dab1 and unphosphorylated Dab1 is capable of binding Fe65. Dab1 interacts with the low‐density lipoprotein receptor‐related protein (LRP) as well as APP through its PTB domain. Dab1 significantly decreased the amount of APP bound to LRP and the level of secreted APP and APP‐CTF in LRP expressing cells, unlike Fe65. It implies that overexpression of Dab1 diminish LRP–APP complex formation, resulting in altered APP processing. The competition for overlapped binding site among adaptor proteins may be related to the regulation mechanism of APP metabolism in various conditions. J. Cell. Biochem. 111: 508–519, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
935.
Hyeong Cheol Park Chan Young Park Sung Cheol Koo Mi Sun Cheong Kyung Eun Kim Min Chul Kim Chae Oh Lim Sang Yeol Lee Dae-Jin Yun Woo Sik Chung 《Plant cell reports》2010,29(11):1297-1304
Plants express many calmodulins (CaMs) and calmodulin-like (CML) proteins that sense and transduce different Ca2+ signals. Previously, we reported divergent soybean (Glycine max) CaM isoforms (GmCaM4/5) with differential abilities to activate CaM-dependent enzymes. To elucidate biological functions
of divergent CaM proteins, we isolated a cDNA encoding a CML protein, AtCML8, from Arabidopsis. AtCML8 shows highest identity with GmCaM4 at the protein sequence level. Expression of AtCML8 was high in roots, leaves, and flowers but low in stems. In addition, the expression of AtCML8 was induced by exposure to salicylic acid or NaCl. AtCML8 showed typical characteristics of CaM such as Ca2+-dependent electrophoretic mobility shift and Ca2+ binding ability. In immunoblot analyses, AtCML8 was recognized only by antiserum against GmCaM4 but not by GmCaM1 antibodies.
Interestingly, AtCML8 was able to activate phosphodiesterase (PDE) but did not activate NAD kinase. These results suggest
that AtCML8 acts as a CML protein in Arabidopsis with characteristics similar to soybean divergent GmCaM4 at the biochemical levels. 相似文献
936.
Koichiro Koyama Yusuke Hirasawa Takahiro Hosoya Teh Chin Hoe Kit-Lam Chan Hiroshi Morita 《Bioorganic & medicinal chemistry》2010,18(12):4415-4421
Eight new indole alkaloids, alpneumines A–H (1–8) were isolated from the Malaysian Alstonia pneumatophora (Apocynaceae) and their structures were determined by MS and 2D NMR spectroscopic methods. Alpneumines E and G (5 and 7), vincamine, and apovincamine showed anti-melanogenesis in B16 mouse melanoma cells. 相似文献
937.
938.
Comparing the 3D structures of proteins is an important but computationally hard problem in bioinformatics. In this paper, we propose studying the problem when much less information or assumptions are available. We model the structural alignment of proteins as a combinatorial problem. In the problem, each protein is simply a set of points in the 3D space, without sequence order information, and the objective is to discover all large enough alignments for any subset of the input. We propose a data-mining approach for this problem. We first perform geometric hashing of the structures such that points with similar locations in the 3D space are hashed into the same bin in the hash table. The novelty is that we consider each bin as a coincidence group and mine for frequent patterns, which is a well-studied technique in data mining. We observe that these frequent patterns are already potentially large alignments. Then a simple heuristic is used to extend the alignments if possible. We implemented the algorithm and tested it using real protein structures. The results were compared with existing tools. They showed that the algorithm is capable of finding conserved substructures that do not preserve sequence order, especially those existing in protein interfaces. The algorithm can also identify conserved substructures of functionally similar structures within a mixture with dissimilar ones. The running time of the program was smaller or comparable to that of the existing tools. 相似文献
939.
Young Sik Cho Seung Yeon Park Hee Suk Shin Francis Ka-Ming Chan 《Molecules and cells》2010,29(4):327-332
Cell death occurs spontaneously or in response to external stimuli, and can be largely subdivided into apoptosis and necrosis
by the distinct morphological and biochemical features. Unlike apoptosis, necrosis was recognized as the passive and unwanted
cell demise committed in a non-regulated and disorganized manner. However, under specific conditions such as caspase intervention,
necrosis has been proposed to be regulated in a well-orchestrated way as a backup mechanism of apoptosis. The term programmed
necrosis has been coined to describe such an alternative cell death. Recently, at least some regulators governing programmed
necrosis have been identified and demonstrated to be interconnected via a wide network of signal pathways by further extensive
studies. There is growing evidence that programmed necrosis is not only associated with pathophysiological diseases, but also
provides innate immune response to viral infection. Here, we will introduce recent updates on the molecular mechanism and
physiological significance of programmed necrosis. 相似文献
940.