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   2402篇
  免费   106篇
  国内免费   11篇
耳鼻咽喉   83篇
儿科学   41篇
妇产科学   24篇
基础医学   272篇
口腔科学   17篇
临床医学   317篇
内科学   511篇
皮肤病学   14篇
神经病学   143篇
特种医学   63篇
外科学   459篇
综合类   27篇
预防医学   48篇
眼科学   34篇
药学   222篇
中国医学   14篇
肿瘤学   230篇
  2022年   17篇
  2021年   39篇
  2019年   24篇
  2018年   31篇
  2017年   23篇
  2016年   17篇
  2015年   34篇
  2014年   47篇
  2013年   48篇
  2012年   87篇
  2011年   93篇
  2010年   57篇
  2009年   52篇
  2008年   90篇
  2007年   79篇
  2006年   80篇
  2005年   76篇
  2004年   78篇
  2003年   74篇
  2002年   98篇
  2001年   109篇
  2000年   89篇
  1999年   93篇
  1998年   30篇
  1997年   25篇
  1996年   16篇
  1995年   18篇
  1994年   14篇
  1992年   53篇
  1991年   57篇
  1990年   51篇
  1989年   80篇
  1988年   49篇
  1987年   58篇
  1986年   77篇
  1985年   93篇
  1984年   41篇
  1983年   44篇
  1982年   20篇
  1981年   17篇
  1979年   41篇
  1978年   28篇
  1977年   19篇
  1976年   18篇
  1975年   25篇
  1974年   26篇
  1973年   22篇
  1970年   29篇
  1969年   24篇
  1968年   18篇
排序方式: 共有2519条查询结果,搜索用时 15 毫秒
91.
92.
We have systematically characterized gene expression patterns in 49 adult and embryonic mouse tissues by using cDNA microarrays with 18,816 mouse cDNAs. Cluster analysis defined sets of genes that were expressed ubiquitously or in similar groups of tissues such as digestive organs and muscle. Clustering of expression profiles was observed in embryonic brain, postnatal cerebellum, and adult olfactory bulb, reflecting similarities in neurogenesis and remodeling. Finally, clustering genes coding for known enzymes into 78 metabolic pathways revealed a surprising coordination of expression within each pathway among different tissues. On the other hand, a more detailed examination of glycolysis revealed tissue-specific differences in profiles of key regulatory enzymes. Thus, by surveying global gene expression by using microarrays with a large number of elements, we provide insights into the commonality and diversity of pathways responsible for the development and maintenance of the mammalian body plan.  相似文献   
93.
94.
BACKGROUND: Spinocerebellar ataxia type 1 (SCA1) is one of the autosomal dominant neurodegenerative disorders commonly linked to pathological expansion of the CAG repeat of the relevant gene. Nuclear inclusions and neurodegeneration are both triggered by this pathological expansion of the CAG/polyglutamine repeat on ataxin-1, but it remains to be determined whether or not nuclear inclusion formation is associated with accelerated neurodegeneration. OBJECTIVE: To examine the influence of nuclear inclusions on nuclear size and deformity in human brains from patients suffering from SCA1. MATERIAL: Pontine sections of brains obtained at necropsy from seven patients with SCA1 and five controls. METHODS: The size and deformity of each neuronal nucleus was quantified. Nuclei with and without inclusions were examined separately to assess the possible influence of nuclear inclusions on neurodegeneration. RESULTS: Nuclear shrinkage and deformity were more marked in SCA1 brains than in controls. This shrinkage was attenuated in neurones containing nuclear inclusions. CONCLUSIONS: The existence of nuclear inclusions in SCA1 is presumably linked to a mechanism that attenuates rather than accelerates nuclear shrinkage. This in vivo finding may provide a clue to constructing a rational therapeutic strategy for combating neurodegeneration associated with nuclear inclusions.  相似文献   
95.
A 57-year-old woman was hospitalized with a left renal artery aneurysm (RAA). The aneurysm measured 35 mm in diameter and was located at the renal artery bifurcation. We performed a laparoscopic nephrectomy using a retroperitoneal approach and performed an ex vivo repair of the renal artery. The reconstructed kidney was then autotransplanted at the left iliac fossa. The patient's postoperative course was uneventful. A laparoscopic nephrectomy and ex vivo repair are both considered to be effective for treating complex RAA.  相似文献   
96.
BACKGROUND: The prognosis for the hepatocellular carcinoma (HCC) patient is affected by invasion and metastases. The attenuated expression of adherens junction protein epithelial-cadherin (E-cad) correlates with a more malignant potential in HCC. However, the potential of the claudin (CL) family of tight junctional proteins for HCC prognosis has remained unrecognized. MATERIALS AND METHODS: We immunohistochemically examined the expression of CL-1 and E-cad in resected specimens from 55 HCC cases. The percentage of CL-1- or E-cad-positive cells was counted in HCC cells and the surrounding hepatocytes and scored as 0 (0%), 1 (1-33%), 2 (34-66%), and 3 (67-100%). The expression of CL-1 or E-cad was considered "preserved" if the score in HCC was equal to or more than that in the surrounding hepatocytes, and "attenuated" if not so. RESULTS: In nontumorous tissue, CL-1 and E-cad were observed at the lateral surface of hepatocytes and biliary epithelial cells. In well-differentiated HCCs, the expression of CL-1 and E-cad was preserved in 12 of 14 cases. In poorly differentiated HCCs, E-cad expression was preserved in 9 of 18 cases, while CL-1 expression was preserved in only 4 cases (P<0.01 versus well-differentiated HCCs). HCCs with portal invasion showed significantly attenuated CL-1 expression than those without portal invasion (P<0.05). The survival rate after hepatectomy for HCC with attenuated CL-1 expression was significantly lower than that for HCC with preserved CL-1 expression. CONCLUSIONS: Attenuated expression of CL-1 closely correlates with the dedifferentiation and portal invasion of HCC. Down-regulated CL-1 expression may serve as a potential marker for a poor prognosis in HCC.  相似文献   
97.
98.
99.
We previously reported that about 80% of vesicular glutamate transporter 3 (VGLUT3)‐positive cells displayed immunoreactivity for serotonin, but the others were negative in the rat midbrain raphe nuclei, such as the dorsal (DR) and median raphe nuclei (MnR). In the present study, to investigate the precise distribution of VGLUT3‐expressing nonserotonergic neurons in the DR and MnR, we performed double fluorescence in situ hybridization for VGLUT3 and tryptophan hydroxylase 2 (TPH2). According to the distribution of VGLUT3 and TPH2 mRNA signals, we divided the DR into six subregions. In the MnR and the rostral (DRr), ventral (DRV), and caudal (DRc) parts of the DR, VGLUT3 and TPH2 mRNA signals were frequently colocalized (about 80%). In the lateral wings (DRL) and core region of the dorsal part of the DR (DRDC), TPH2‐producing neurons were predominantly distributed, and about 94% of TPH2‐producing neurons were negative for VGLUT3 mRNA. Notably, in the shell region of the dorsal part of the DR (DRDSh), VGLUT3 mRNA signals were abundantly detected, and about 75% of VGLUT3‐expressing neurons were negative for TPH2 mRNA. We then examined the projection of VGLUT3‐expressing nonserotonergic neurons in the DRDSh by anterograde and retrograde labeling after chemical depletion of serotonergic neurons. The projection was observed in various brain regions such as the ventral tegmental area, substantia nigra pars compacta, hypothalamic nuclei, and preoptic area. These results suggest that VGLUT3‐expressing nonserotonergic neurons in the midbrain raphe nuclei are preferentially distributed in the DRDSh and modulate many brain regions with the neurotransmitter glutamate via ascending axons. J. Comp. Neurol. 518:668–686, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   
100.
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