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   2595篇
  免费   239篇
  国内免费   24篇
  2858篇
  2024年   6篇
  2023年   39篇
  2022年   56篇
  2021年   84篇
  2020年   78篇
  2019年   65篇
  2018年   103篇
  2017年   74篇
  2016年   66篇
  2015年   108篇
  2014年   174篇
  2013年   163篇
  2012年   150篇
  2011年   192篇
  2010年   130篇
  2009年   97篇
  2008年   129篇
  2007年   136篇
  2006年   114篇
  2005年   79篇
  2004年   94篇
  2003年   78篇
  2002年   75篇
  2001年   42篇
  2000年   18篇
  1999年   17篇
  1998年   23篇
  1997年   27篇
  1996年   16篇
  1995年   26篇
  1994年   29篇
  1993年   27篇
  1992年   17篇
  1991年   19篇
  1990年   19篇
  1989年   12篇
  1988年   10篇
  1987年   11篇
  1986年   8篇
  1985年   20篇
  1984年   45篇
  1983年   34篇
  1982年   36篇
  1981年   24篇
  1980年   16篇
  1979年   25篇
  1978年   18篇
  1977年   7篇
  1974年   5篇
  1971年   5篇
排序方式: 共有2858条查询结果,搜索用时 15 毫秒
1.
2.
Morphometric Analysis of Hepatocellular carcinomaLaiMao-de(来茂德);ChenPei-hui(陈培辉)andZhouShui-yun(周水云)(DepartmentofPathology,Zh...  相似文献   
3.
Enhancement of acetaldehyde-protein adduct formation by L-ascorbate   总被引:5,自引:0,他引:5  
The effect of L-ascorbate on the binding of [14C]acetaldehyde to bovine serum albumin was examined. In the absence of ascorbate, acetaldehyde reacted with albumin to form both unstable (Schiff bases) and stable adducts. Ascorbate (5 mM) caused a time-dependent increase in the formation of total acetaldehyde-albumin adducts, which were comprised mainly of stable adducts. Significant enhancement of adduct formation by ascorbate was observed at acetaldehyde concentrations as low as 5 microM. An ascorbate concentration as low as 0.5 mM was still effective in stimulating stable adduct formation. The electron acceptor, 2,6 dichlorophenolindophenol, prevented the ascorbate-induced increase in albumin-adduct formation. Ascorbate also caused enhanced acetaldehyde adduct formation with other purified proteins, including cytochrome c and histones, as well as the polyamino acid, poly-L-lysine. These results indicate that ascorbate, acting as a reducing agent, can convert unstable acetaldehyde adducts to stable adducts, and can thereby increase and stabilize the binding of acetaldehyde to proteins.  相似文献   
4.
Pretreatment of Chang liver cells with N-ethylmaleimide (0.5 or 1 mM) stimulated Na+-independent uptake of leucine at low concentrations (?1 mM). The stimulatory effect of N-ethylmaleimide on the uptake of leucine measured in Na+-replete medium was completely blocked by the addition of b-2-aminobicyclo[2,2,1]heptane-2-carboxylate (5 mM), which shows that the L system participates in the stimulation. The Na+-dependent uptake of glycine was depressed by N-ethylmaleimide pretreatment. The stimulation of the Na+-independent component of leucine uptake continued for at least 30 min after N-ethylmaleimide treatment, while the inhibition of glycine uptake was progressive with time and the Na+-dependent uptake of leucine became depressed later, after the treatment. It has been demonstrated that treatment of cells with N-ethylmaleimide is capable of increasing the Na+-independent influx of leucine and at the same time slightly decreasing the efflux of it. These results suggest that N-ethylmaleimide attacks the Na+-independent system of amino acid transport at the reactive SH groups(s) of relevant protein(s) in favor of specific activation of that system in this cell.  相似文献   
5.
6.
Against the background of cercarial fine structure, ultrastructural changes were compared in schistosomules of Schistosoma mansoni 30 min and 1 hr after their production in vivo by skin penetration and in vitro by shear pressure. The same developmental pattern was observed in schistosomules of both derivations. In vitro schistosomules, however, developed more slowly, resembled cercariae more closely, and varied less among organisms than did in vivo schistosomules. The greatest morphological changes were observed in the 1-hr in vivo schistosomules. These were as follows: (1) in tegument, formation of transient microvilli, a hepatalaminate outer membrane and accented surface invaginations, loss of glycocalyx, movement outward of cyton vesicles via bridges, accumulation of multilaminate bodies around bridge openings; (2) in the anterior organ (oral sucker), movement of head gland vesicles via the ducts into tegument followed by collapse of the gland fundus, disappearance of the circumfundal cells and two large support cells, and the appearance in these areas of membranes and parenchymal cells; (3) secretion of the acetabular gland contents, collapse of the glands and replacement by membranes and parenchymal cells; (4) peristaltic activity of the digestive tract as shown by alternate areas of lumen constriction and dilation; (5) loss of bladder and contraction of the small aboral collecting tubules; and (6) conversion of heterochromatic parenchymal cell nuclei to euchromatic. In contrast, the 1-hr in vitro shear schistosomules resembled 30-min in vivo schistosomules, retaining many cercarial features.  相似文献   
7.
The liver has an extraordinary regenerative capacity rapidly triggered upon injury or resection. This response is intrinsically adjusted in its initiation and termination, a property termed the “hepatostat”. Several molecules have been involved in liver regeneration, and among them bile acids may play a central role. Intrahepatic levels of bile acids rapidly increase after resection. Through the activation of farnesoid X receptor (FXR), bile acids regulate their hepatic metabolism and also promote hepatocellular proliferation. FXR is also expressed in enterocytes, where bile acids stimulate the expression of fibroblast growth factor 15/19 (FGF15/19), which is released to the portal blood. Through the activation of FGFR4 on hepatocytes FGF15/19 regulates bile acids synthesis and finely tunes liver regeneration as part of the “hepatostat”. Here we review the experimental evidences supporting the relevance of the FXR-FGF15/19-FGFR4 axis in liver regeneration and discuss potential therapeutic applications of FGF15/19 in the prevention of liver failure. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.  相似文献   
8.
9.
摘要 目的:观察腕踝针联合耳穴压豆治疗原发性肝癌(PHC)癌痛的疗效及对心理状态和血清疼痛介质的影响。方法:选取湖南中医药大学第一附属医院2020年3月~2022年12月期间收治的PHC癌痛患者117例,按随机数字表法分为对照组和联合组,例数分别为58例和59例。两组患者均接受常规疼痛处理,对照组患者接受耳穴压豆治疗,联合组在对照组的基础上接受腕踝针治疗。对比两组疼痛缓解率、临床指标、心理状态和疼痛介质水平。结果:联合组的疼痛缓解率高于对照组(P<0.05)。联合组的数字疼痛法(NRS)评分低于对照组,止痛起效时间、每次疼痛持续时间短于对照组,爆发痛次少于对照组(P<0.05)。治疗后,两组焦虑自评量表(SAS)、抑郁自评量表(SDS)评分下降,且联合组低于对照组(P<0.05)。治疗后,两组5-羟色胺(5-HT)、P物质(SP)、前列腺素E2(PGE2)下降,且联合组低于对照组(P<0.05)。结论:腕踝针联合耳穴压豆治疗PHC癌痛,可有效减轻疼痛症状,降低血清疼痛介质水平,同时还可有效调节患者的心理状态,应用价值较好。  相似文献   
10.
摘要 目的:探讨针灸联合逍遥散合半夏厚朴汤治疗肝郁脾虚型抑郁症患者伴胃肠功能紊乱的临床疗效。方法:选取我院2020年5月到2023年5月收治的80例抑郁症伴胃肠功能紊乱患者作为研究对象,中医证型均为肝郁脾虚型,分为观察组与对照组,40例。对照组患者采取逍遥散合半夏厚朴汤治疗,观察组在对照组基础上增加针灸治疗,对比两组患者临床疗效,分别在治疗前后应用汉密尔顿抑郁量表(HAMD)、负性认知加工偏向问卷(NCPBQ)评价抑郁症状和负性认知情况,并对比治疗前后肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)、白细胞介素-6(IL-6)表达水平和胃动素(motilin,MTL)、生长抑素(SS)、胃泌素(GAS)相关血清肠胃激素表达水平,并采用世界卫生组织生活质量-100量表(WHOQOL-100)评估生活质量。结果:观察组治疗总有效率较对照组高(P<0.05);治疗前两组患者HAMD、NCPBQ评分对比无差异(P>0.05),治疗后两组患者均降低,且观察组较对照组低(P<0.05);治疗前两组患者TNF-α、CRP、IL-6相关炎症因子和MTL、SS、GAS相关胃肠激素水平对比无明显差异(P>0.05),治疗后两组患者TNF-α、CRP、IL-6、SS、GAS水平均降低,且观察组较对照组低,MTL水平升高,观察组较对照组高(P<0.05);两组患者治疗后生活质量相关评分均升高,且观察组较对照组高(P<0.05)。结论:针灸联合逍遥散合半夏厚朴汤治疗肝郁脾虚型抑郁症伴胃肠功能紊乱疗效显著,可减轻患者抑郁情绪和负性认知,降低炎症反应,改善胃肠激素水平,提升患者生活质量。  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