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   3646篇
  免费   319篇
  国内免费   73篇
  2024年   8篇
  2023年   82篇
  2022年   108篇
  2021年   141篇
  2020年   100篇
  2019年   134篇
  2018年   108篇
  2017年   102篇
  2016年   70篇
  2015年   109篇
  2014年   180篇
  2013年   196篇
  2012年   125篇
  2011年   173篇
  2010年   111篇
  2009年   146篇
  2008年   160篇
  2007年   163篇
  2006年   163篇
  2005年   123篇
  2004年   155篇
  2003年   112篇
  2002年   110篇
  2001年   90篇
  2000年   77篇
  1999年   76篇
  1998年   68篇
  1997年   52篇
  1996年   65篇
  1995年   70篇
  1994年   63篇
  1993年   49篇
  1992年   46篇
  1991年   62篇
  1990年   45篇
  1989年   54篇
  1988年   39篇
  1987年   25篇
  1986年   30篇
  1985年   31篇
  1984年   34篇
  1982年   30篇
  1981年   25篇
  1980年   18篇
  1979年   20篇
  1978年   21篇
  1977年   15篇
  1976年   10篇
  1973年   10篇
  1971年   10篇
排序方式: 共有4038条查询结果,搜索用时 15 毫秒
1.
《Developmental cell》2021,56(21):2952-2965.e9
  1. Download : Download high-res image (167KB)
  2. Download : Download full-size image
  相似文献   
2.
Summary The horseradish-peroxidase (HRP) technique was used to visualize the cell bodies of axons projecting to the goldfish pituitary. Following intravenous injections of HRP, HRP reaction products were observed in axons of the rostral pars distalis, proximal pars distalis, neurointermediate lobe, pituitary stalk and in axons coursing from the pituitary into the hypothalamus. HRP-labelled cells in the brain were localized in two regions only — the nucleus preopticus (NPO) pars magnocellularis and pars parvocellularis, and the nucleus lateralis tuberis (NLT) of the hypothalamus. These observations suggest that the NPO and NLT are the source of the neurosecretory innervation of the goldfish pituitary.  相似文献   
3.
《Cell reports》2020,30(1):164-172.e4
  1. Download : Download high-res image (143KB)
  2. Download : Download full-size image
  相似文献   
4.
Parkin mutations produce Parkinson’s disease (PD) in humans and nigrostriatal dopamine lesions related to increased free radicals in mice. We examined the effects of NP7, a synthetic, marine derived, free radical scavenger which enters the brain, on H2O2 toxicity in cultured neurons and glia from wild-type (WT) and parkin null mice (PK-KO).NP7, 5-10 μM, prevented the H2O2 induced apoptosis and necrosis of midbrain neuronal and glial cultures from WT and PK-KO mice. NP7 suppressed microglial activation and the H2O2 induced drop-out of dopamine neurons. Furthermore, NP7 prevented the increased phosphorylation of ERK and AKT induced by H2O2. NP7 may be a promising neuroprotector against oxidative stress in PD.  相似文献   
5.
6.
Summary This study is concerned with electron-microscopic observations on endocrine or paracrine cells in the fundic gastric mucosa of the bullfrog. Also, an attempt was made to identify the histamine-releasing cells involved in the secretagogue response. At least three distinct endocrine-like cell types were found. The classification is based on the appearance of secretory granules and other organelles, and the relationship of endocrine-like cells with other cells in the tissue. The amphibian endocrine-like cells resemble the ECL, D and EC cells of mammals. Type-I (ECL) cells showed degranulation after repeated stimulation with tetragastrin (TG), acetylcholine (ACh) and K+ depolarizing solution, all of which release histamine.  相似文献   
7.
8.
《Current biology : CB》2020,30(5):827-839.e4
  1. Download : Download high-res image (204KB)
  2. Download : Download full-size image
  相似文献   
9.
Using immunohistochemical labeling against acetylated a‐tubulin and serotonin in combination with confocal laser scanning microscopy and 3D‐reconstruction, we investigated the temporary freshwater pond inhabitant Branchinella sp. (Crustacea: Branchiopoda: Anostraca) for the first time to provide detailed data on the development of the anostracan nervous system. Protocerebral sense organs such as the nauplius eye and frontal filament organs are present as early as the hatching stage L0. In the postnaupliar region, two terminal pioneer neurons grow from posterior to anterior to connect the mandibular neuromeres. The first protocerebral neuropil to emerge is not part of the central complex but represents the median neuropil, and begins to develop from L0+ onwards. In stage L3, the first evidence of developing compound eyes is visible. This is followed by the formation of the visual neuropils and the neuropils of the central complex in the protocerebrum. From the deutocerebral lobes, the projecting neuron tract proceeds to both sides of the lateral protocerebrum, forming a chiasma just behind the central body. In the postnaupliar region, the peripheral nervous system, commissures and connectives develop along an anterior–posterior gradient after the fasciculation of the terminal pioneer neurons with the mandibular neuromere. The peripheral nervous system in the thoracic segments consists of two longitudinal neurite bundles on each side which connect the intersegmental nerves, together with the ventral nervous system forming an orthogon‐like network. Here, we discuss, among other things, the evidence of a fourth nauplius eye nerve and decussating projecting neuron tract found in Branchinella sp., and provide arguments to support our view that the crustacean frontal filament (organ) and onychophoran primary antenna are homologous. J. Morphol. 277:1423–1446, 2016. © 2016 Wiley Periodicals, Inc.  相似文献   
10.
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