首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3854篇
  免费   347篇
  国内免费   206篇
  2024年   10篇
  2023年   148篇
  2022年   143篇
  2021年   242篇
  2020年   160篇
  2019年   190篇
  2018年   163篇
  2017年   104篇
  2016年   123篇
  2015年   179篇
  2014年   279篇
  2013年   278篇
  2012年   160篇
  2011年   195篇
  2010年   175篇
  2009年   185篇
  2008年   217篇
  2007年   215篇
  2006年   187篇
  2005年   143篇
  2004年   149篇
  2003年   128篇
  2002年   101篇
  2001年   84篇
  2000年   49篇
  1999年   61篇
  1998年   59篇
  1997年   38篇
  1996年   38篇
  1995年   39篇
  1994年   26篇
  1993年   44篇
  1992年   23篇
  1991年   11篇
  1990年   8篇
  1989年   5篇
  1988年   6篇
  1987年   4篇
  1986年   5篇
  1985年   6篇
  1984年   2篇
  1983年   4篇
  1982年   10篇
  1981年   1篇
  1980年   3篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
  1974年   1篇
排序方式: 共有4407条查询结果,搜索用时 31 毫秒
1.
The growth-associated protein B-50 also termed GAP-43, F1, pp46, P-57 and neuromodulin is a nervous tissuespecific protein kinase C (PKC) substrate that is considered to play a major role in neurite formation, regeneration, and neuroplasticity. We describe the isolation of seven mouse monoclonal antibodies (Mabs) directed against B-50. The Mabs are produced against the bovine B-50, selected by ELISA for cross-reactivity with its human counterpart, and evaluated on Western blots in comparison with the well-characterized affinity-purified rabbit polyclonal antibodies to rat-B-50. The Western blots show that the Mabs NM1, NM4, and NM6 recognize specifically the B-50 of bovine, human, and rat brain extract and the purified PKC phosphorylated and unphosphorylated rat B-50 isoforms. The Mabs NM2 and NM3 cross-react with bovine B-50 immunoreactive c-kinase substrate (BICKS), a protein sharing a 17 amino acid sequence homology with B-50. Two Mabs are useful for the detection of B-50 immunoreactivity in formalin-fixed human and rat brain tissues. In human specimen of the hippocampus, a characteristic neuropil distribution of B-50 is detected by the Mabs. In human muscle, Mabs reveal B-50 in nerve bundles and in axons at motor end plates. Thus, these Mabs are useful in investigating the function and localization of the B-50 protein.  相似文献   
2.
Fish finders have already been widely available in the fishing market for a number of years.However,the sizes of these fishfinders are too big and their prices are expensive to suit for the research of robotic fish or mini-submarine.The goal of thisresearch is to propose a low-cost fish detector and classifier which suits for underwater robot or submarine as a proximity sensor.With some pre-condition in hardware and algorithms,the experimental results show that the proposed design has good per-formance,with a detection rate of 100 % and a classification rate of 94 %.Both the existing type of fish and the group behaviorcan be revealed by statistical interpretations such as hovering passion and sparse swimming mode.  相似文献   
3.
4.
5.
6.
《Developmental cell》2022,57(9):1193-1207.e7
  1. Download : Download high-res image (146KB)
  2. Download : Download full-size image
  相似文献   
7.
1IntroductionElbo(ECG)offersalotofilllcorralltinfondionforthediagnosisOfheartdis-eases.Berz1,seahaormalEChcax[lrins>llleu"knownsituations,thcycanbeCSUghtinthelongti1Ylecontin~11xHlltoriDg.ndterrnoultonngsystemwhichcanrecord24-hoUrECGdataisoneofeffectiveme~toprovidethefun~.AlthOUghthehag6scaleICmorestohavebeeddevelopepbedeavailabletostorelOngtboeECGdsta,itisveqdifficultyandtioublesomethatalopnUmbeOfdstaisprasersandstoredortiallsillltted.InthedigitedECGdata,thereare…  相似文献   
8.
《Neuron》2020,105(6):1077-1093.e7
Download : Download video (97MB)  相似文献   
9.
We present a simple model describing the transition between the prefiring, firing and postfiring phases of a single neuron in a large neural net. Using typical values for the physiological parameters that enter the model, we find average interspike times that are close to those reported in experimental measurements.  相似文献   
10.
1. Recombinant retroviruses were used to introduce a temperature-sensitive v-src gene and oncogenic c-Ha-ras into PC12 cells, and stable cell lines expressing these genes were established. 2. As previously reported, expression of v-src (Alema et al., 1985) or c-Ha-ras (Noda et al., 1985) in PC12 cells results in neurite outgrowth resembling that induced by NGF. We report here that v-src but not oncogenic c-Ha-ras induces a stable morphologic neuronal differentiation similar to treatment with NGF. Oncogenic c-Ha-ras-induced neurite outgrowth is not stable with long-term culture, rather the cells revert to an undifferentiated morphology with altered cell cycle kinetics. 3. The stable neuronal phenotype induced by v-src and NGF is characterized by the functional expression of dihydropyridine-insensitive calcium currents.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号