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   1834篇
  免费   127篇
  2023年   15篇
  2022年   22篇
  2021年   51篇
  2020年   28篇
  2019年   39篇
  2018年   48篇
  2017年   45篇
  2016年   79篇
  2015年   111篇
  2014年   108篇
  2013年   123篇
  2012年   167篇
  2011年   154篇
  2010年   100篇
  2009年   82篇
  2008年   109篇
  2007年   83篇
  2006年   98篇
  2005年   85篇
  2004年   72篇
  2003年   80篇
  2002年   55篇
  2001年   17篇
  2000年   15篇
  1999年   18篇
  1998年   15篇
  1997年   20篇
  1996年   9篇
  1995年   12篇
  1994年   10篇
  1993年   6篇
  1992年   7篇
  1991年   10篇
  1990年   5篇
  1989年   2篇
  1988年   5篇
  1987年   2篇
  1986年   2篇
  1985年   3篇
  1984年   6篇
  1983年   5篇
  1982年   5篇
  1981年   4篇
  1980年   3篇
  1977年   3篇
  1974年   4篇
  1973年   2篇
  1972年   2篇
  1968年   2篇
  1966年   2篇
排序方式: 共有1961条查询结果,搜索用时 31 毫秒
1.
Salt-sensitive hypertension is a major risk factor for renal impairment leading to chronic kidney disease. High-salt diet leads to hypertonic skin interstitial volume retention enhancing the activation of the tonicity-responsive enhancer-binding protein (TonEBP) within macrophages leading to vascular endothelial growth factor C (VEGF-C) secretion and NOS3 modulation. This promotes skin lymphangiogenesis and blood pressure regulation. Whether VEGF-C administration enhances renal and skin lymphangiogenesis and attenuates renal damage in salt-sensitive hypertension remains to be elucidated. Hypertension was induced in BALB/c mice by a high-salt diet. VEGF-C was administered subcutaneously to high-salt-treated mice as well as control animals. Analyses of kidney injury, inflammation, fibrosis, and biochemical markers were performed in vivo. VEGF-C reduced plasma inflammatory markers in salt-treated mice. In addition, VEGF-C exhibited a renal anti-inflammatory effect with the induction of macrophage M2 phenotype, followed by reductions in interstitial fibrosis. Antioxidant enzymes within the kidney as well as urinary RNA/DNA damage markers were all revelatory of abolished oxidative stress under VEGF-C. Furthermore, VEGF-C decreased the urinary albumin/creatinine ratio and blood pressure as well as glomerular and tubular damages. These improvements were associated with enhanced TonEBP, NOS3, and lymphangiogenesis within the kidney and skin. Our data show that VEGF-C administration plays a major role in preserving renal histology and reducing blood pressure. VEGF-C might constitute an interesting potential therapeutic target for improving renal remodeling in salt-sensitive hypertension.  相似文献   
2.
3.
Established osteoblast-like (OB) cells infected with the bone tumor-inducing C-type retrovirus OA MuLV remained nontumorigenic over 104 cell culture passages. DNA histograms revealed a new cell population with a stem line peak at 5c. A second OA MuLV-infected OB cell line underwent neoplastic transformation with increasing passage level. These cells showed diffuse aneuploidy. Stepwise linear discriminant analysis of the chromatin structure of control, OA MuLV-infected, and FBR osteosarcoma virus-transformed cell lines resulted in various levels of discrimination ranging between 79.6% for control cells versus nontumorigenic OA MuLV-infected cells, and 96.6% for nontumorigenic OA MuLV-infected cells versus FBR osteosarcoma virus-transformed cells. OA MuLV-infected tumorigenic cells and FBR osteosarcoma virus-transformed cells were discriminated at a 93.6% level.  相似文献   
4.
Summary -Hydroxybutyric acid (GHB) is a natural compound of mammalian brain synthesized from GABA. The characteristics of its synthesis, transport, release, distribution and turnover, in addition to the presence of a high affinity binding site for this substance in brain are in favor of a modulator role for GHB. The effects of hydrolytic enzymes on the specific binding capacity of GHB have been studied in the present work. Phospholipases A2 and C, neuraminidase and Pronase markedly decrease GHB binding to crude synaptosomal membranes from rat brain. This effect is time and enzyme concentration dependent. Trypsin, under the conditions employed, is less active. The inhibitory effects of phospholipases is correlated with phospholipid hydrolysis. Lysophospholipids, in the absence of bovine fatty acid free serum albumin partially inhibit GHB binding. The action of neuraminidase has been followed by sialic acid release and modifications of the ganglioside profile. The effects of phospholipase C and of neuraminidase are completely different to those on GABA binding sites. These results represent further data concerning the molecular existence of specific GHB binding sites on rat brain membranes.Abbreviations GHB -hydroxybutyrate - LPC L--lysophosphatidylcholine - LPE Lysophosphatidylethanolamine - PC Phosphatidylcholine - PE Phosphatidylethanolamine - BSA Bovine Serum Albumin  相似文献   
5.
6.
7.
N Luz  E Beck 《Journal of virology》1991,65(12):6486-6494
A cellular 57-kDa protein (p57) that binds specifically to the internal translation initiation site in the 5' untranslated region of foot-and-mouth disease virus RNA was detected in cell extracts of different mammalian species by UV cross-linking. The protein binds to two distinct sites of the translation control region which have as the only common sequence a UUUC motif. The first binding site consists of a conserved hairpin structure, whereas the second binding site contains an essential pyrimidine-rich region without obvious secondary structure. Competition experiments indicate that the complexes with the two binding sites were formed by a single p57 species. The protein binds also to the 5' untranslated region of other picornaviruses. Results from footprint analyses with foot-and-mouth disease RNA suggest the participation of additional cellular factors in the translation initiation complex.  相似文献   
8.
9.
The sulfated glycosaminoglycans synthesized by human smooth muscle cells isolated from different organs were identified on the basis of electrophoretic mobility, enzymatic degradation with specific mucopolysaccharidases and by the type of degradation products formed. The results obtained indicated that chondroitin sulfate and heparan sulfate were the main glycosaminoglycans found, that most of the labeled glycosaminoglycans were found in the pericellular pool, and that no marked differences were observed in the sulfated glycosaminoglycan composition of the smooth muscle cells obtained from different organs. 'Liver connective tissue cells', isolated from pathological livers (which had been shown to possess biochemical and physiological features typical of smooth muscle cells) showed a pattern of glycosaminoglycan synthesis similar to that of the smooth muscle cells.  相似文献   
10.
This paper reports a study of body height in the adult Jewish population of Israel, comparing native-born with immigrant groups. The sample tested included 1,411 men and 961 women, all clinically healthy according to the results of multiphasic screening. The phenomenon observed in other immigration-absorbing countries also holds for Israel: native Israelis are significantly taller than their immigrant counterparts. The findings were verified over different age and working activity strata, and thus may be taken to reflect the influence of better socioeconomic and environmental conditions on the bodily development of those born in Israel.  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