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   202451篇
  免费   19263篇
  国内免费   11226篇
耳鼻咽喉   1636篇
儿科学   2855篇
妇产科学   1999篇
基础医学   24796篇
口腔科学   3840篇
临床医学   24497篇
内科学   24797篇
皮肤病学   2342篇
神经病学   8201篇
特种医学   6540篇
外国民族医学   65篇
外科学   18655篇
综合类   39812篇
现状与发展   41篇
一般理论   12篇
预防医学   17102篇
眼科学   4066篇
药学   24082篇
  186篇
中国医学   13727篇
肿瘤学   13689篇
  2024年   684篇
  2023年   2711篇
  2022年   7328篇
  2021年   9383篇
  2020年   7248篇
  2019年   5629篇
  2018年   5956篇
  2017年   6070篇
  2016年   5432篇
  2015年   8407篇
  2014年   10770篇
  2013年   11343篇
  2012年   16189篇
  2011年   17075篇
  2010年   13344篇
  2009年   11179篇
  2008年   12448篇
  2007年   12268篇
  2006年   11175篇
  2005年   9700篇
  2004年   7230篇
  2003年   6699篇
  2002年   5491篇
  2001年   4751篇
  2000年   3953篇
  1999年   2966篇
  1998年   1735篇
  1997年   1862篇
  1996年   1339篇
  1995年   1257篇
  1994年   1149篇
  1993年   811篇
  1992年   1001篇
  1991年   911篇
  1990年   811篇
  1989年   742篇
  1988年   668篇
  1987年   569篇
  1986年   545篇
  1985年   445篇
  1984年   378篇
  1983年   305篇
  1982年   278篇
  1981年   230篇
  1980年   200篇
  1979年   201篇
  1978年   193篇
  1977年   212篇
  1976年   192篇
  1974年   159篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
PurposeWe previously demonstrated that the functional inactivation of DAL-1 and TOB1 promotes an aggressive phenotype in gastric cancer cells, but the links between both genes and the survival of patients with gastric cancer are unknown. Here, we investigated the correlations of the expression levels of DAL-1 and TOB1 with the progression of gastric cancer.MethodsA total of 270 patients who underwent resectable gastrectomy were included. The expression of DAL-1 and TOB1 was detected by immunohistochemistry.ResultsLow expression of DAL-1 in cancer tissue was significantly associated with tumor site (p < 0.05), histological grade (p < 0.01), depth of invasion (p < 0.05), lymph node metastasis status (p < 0.05), Lauren classification (p < 0.001), and clinical stage (p < 0.01). A lower level of TOB1 was observed in gastric cancer patients with diffuse type disease compared to patients with either intestinal or mixed type disease (p < 0.001). Additionally, Spearman’s correlation analysis revealed that decreased expression of DAL-1 was positively correlated with low TOB1 expression (r=0.304, p < 0.001). The survival analysis showed that low levels of DAL-1 and TOB1 were significantly associated with poor survival of gastric cancer patients (p <0.001 and p < 0.05, respectively).ConclusionThe downregulation of DAL-1 and TOB1 expression is associated with shorter survival of gastric cancer patients. Hence, DAL-1 and TOB1 may be considered potential novel markers for predicting the outcomes of patients with gastric cancer.  相似文献   
63.
1. To investigate Genkwa Flos hepatotoxicity, a cell metabolomics strategy combined with serum pharmacology was performed on human HL-7702 liver cells in this study.

2. Firstly, cell viability and biochemical indicators were determined and the cell morphology was observed to confirm the cell injury and develop a cell hepatotoxicity model. Then, with the help of cell metabolomics based on UPLC-MS, the Genkwa Flos group samples were completely separated from the blank group samples in the score plots and seven upregulated as well as two down-regulated putative biomarkers in the loading plot were identified and confirmed. Besides, two signal molecules and four enzymes involved in biosynthesis pathway of lysophosphatidylcholine and the sphingosine kinase/sphingosine-1-phosphate pathway were determined to investigate the relationship between Genkwa Flos hepatotoxicity and these two classic pathways. Finally, the metabolic pathways related to specific biomarkers and two classic metabolic pathways were analyzed to explain the possible mechanism of Genkwa Flos hepatotoxicity.

3. Based on the results, lipid peroxidation and oxidative stress, phospholipase A2/lysophosphatidylcholine pathway, the disturbance of sphingosine-1-phosphate metabolic profile centered on sphingosine kinase/sphingosine-1-phosphate pathway and fatty acid metabolism might be critical participators in the progression of liver injury induced by Genkwa Flos.  相似文献   

64.
Gastric cancer, one of the most common disease, has become a major public health problem worldwide. Cisplatin (DDP) has been a widely used drug for the treatment of cancer, also usually applied in gastric cancer in clinic. However, the side effects including toxicity and drug-resistance restricted the usage of DDP in clinic, so we prepared a DDP-complexed hydrogel (DDP-Gel) and investigated its efficacy in gastric cancer. For in vivo studies, MKN45-Luc cells were injected into BLAB/C node mice subcutaneously to establish gastric cancer with orthotopically grown tumors. Mice bearing tumors were treated with normal saline, DDP and DDP-Gel. Body weight and survival condition were observed and recorded. The treatment efficacy in vivo was detected by luciferase imaging and histological evaluation was performed by H&E staining of different organs. Additionally, normal ICR mice were treated with different doses of DDP/DDP-Gel to calculate their LD50 in vivo. The results showed that DDP-Gel prolonged survival time and ameliorated body weight changes of mice bearing tumors. DDP-Gel exhibited higher efficacy to inhibit tumor growth and metastasis, compared to DDP. Besides, LD50 of DDP-Gel was 166.0?mg/kg, 13.2 folds higher than DDP. As a conclusion, DDP-Gel showed a more effective and safer function than DDP in gastric cancer, which indicating that DDP-Gel might be a novel strategy for gastric cancer therapy.  相似文献   
65.
Neuroscience and Behavioral Physiology - Objective. To determine the frequency, structure, and severity of cognitive impairments in patients with bipolar affective disorder (BAD) in remission....  相似文献   
66.
目的 通过阿霉素(Dox)复制大鼠慢性心力衰竭(CHF)模型,观察Liguzinediol对CHF大鼠心功能的影响。方法 通过血流动力学观察Liguzinediol对Dox(腹腔注射,2 mg/kg)诱导的CHF大鼠左心室内压最大上升/下降速率(±dp/dtmax)、左心室内压(LVSP)、动脉收缩压(ASP)、动脉舒张压(ADP)和心率(HR)的变化;观察Liguzinediol对血清一氧化氮(NO)、一氧化氮合成酶(NOS)、超氧化物歧化酶(SOD)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)以及血浆中丙二醛(MDA)的影响。结果 Liguzinediol能增加LVSP、+dp/dtmax、ASP、ADP、AP、HR,降低-dp/dtmax(P<0.05~0.01);降低NO、iNOS以及MDA的浓度,同时增强了SOD的活性(P<0.05~0.01);抑制IL-6和TNF-α的生成(P<0.05~0.01)。结论 Liguzinediol可明显改善Dox诱导的CHF大鼠血流动力学指标,减少模型大鼠炎症因子的释放以及抑制氧自由基的生成。   相似文献   
67.
68.
69.
70.
双环[1.1.1]戊烷(BCP)是一种具有三维立体结构的桥环骨架,其作为苯环、叔丁基和炔烃的生物电子等排体,已经在药物化学领域得到广泛的应用。随着BCP应用范围的扩大,BCP及其衍生物的合成日益成为研究的热点。本文对BCP衍生物的主要合成策略和方法进行总结,旨在为新药研发人员提供参考。  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