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   79416篇
  免费   7546篇
  国内免费   5368篇
耳鼻咽喉   837篇
儿科学   873篇
妇产科学   1222篇
基础医学   10434篇
口腔科学   1405篇
临床医学   10447篇
内科学   11572篇
皮肤病学   1027篇
神经病学   4381篇
特种医学   3086篇
外国民族医学   53篇
外科学   8328篇
综合类   10673篇
现状与发展   21篇
一般理论   22篇
预防医学   4894篇
眼科学   2948篇
药学   8412篇
  65篇
中国医学   4147篇
肿瘤学   7483篇
  2024年   90篇
  2023年   1091篇
  2022年   1619篇
  2021年   3490篇
  2020年   2981篇
  2019年   2881篇
  2018年   3067篇
  2017年   2540篇
  2016年   2641篇
  2015年   3802篇
  2014年   4716篇
  2013年   4167篇
  2012年   6178篇
  2011年   6616篇
  2010年   4078篇
  2009年   3089篇
  2008年   4289篇
  2007年   4234篇
  2006年   4256篇
  2005年   4090篇
  2004年   2774篇
  2003年   2534篇
  2002年   2075篇
  2001年   1792篇
  2000年   1775篇
  1999年   2045篇
  1998年   1273篇
  1997年   1264篇
  1996年   957篇
  1995年   907篇
  1994年   779篇
  1993年   495篇
  1992年   601篇
  1991年   514篇
  1990年   478篇
  1989年   423篇
  1988年   371篇
  1987年   292篇
  1986年   250篇
  1985年   212篇
  1984年   129篇
  1983年   88篇
  1982年   42篇
  1981年   53篇
  1980年   31篇
  1979年   64篇
  1978年   24篇
  1974年   27篇
  1973年   18篇
  1968年   16篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
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   

52.
53.
International Urology and Nephrology - Autosomal dominant polycystic kidney disease (ADPKD) is considered as a tumor-like disease because there are many biological similarities between ADPKD and...  相似文献   
54.
55.
56.
Gold nanoparticle is an important photothermal conversion material in photothermal imaging and photothermal therapy research. There are diverse gold nanoparticles, including gold nanospheres, gold nanorods, gold nanocages, gold nanoshells and gold nanostars. Among them, gold nanostar (AuNS) possesses more excellent prospective imaging contrast agent for cancer diagnosis than other shapes of gold nanoparticles because of its larger photon interception area and cross section as well asscattering characteristics. The properties of AuNS are susceptible to synthetic methods and conditions. In this study, we presented surfactant-free methods to synthesize AuNS, discussed the relationship of AuNS characterization with the synthetic conditions and tested its photothermal effect. The results indicated that length and number of branches in AuNSs were the main factor for absorption wavelength in photothermal conversion, and the AuNSs could be more precisely controlled by changing the synthesis conditions.  相似文献   
57.
58.
BackgroundForkhead box protein P1 (FOXP1) has been suggested as a prognostic marker in several malignant tumors. However, the significance of FOXP1 in esophageal squamous cell carcinoma (ESCC) is still unclear. The purpose of this study was to investigate the expression pattern of FOXP1 in normal esophageal tissue and ESCC and to analyze the clinicopathological significance and prognostic value of FOXP1 in ESCC.MethodsFOXP1 was detected by immunohistochemistry using tissue microarrays containing tumor tissues and adjacent normal tissues from 270 ESCC patients with oncological follow-up data.ResultsNormal esophageal tissues predominantly showed an exclusive nuclear FOXP1 (n-FOXP1) expression pattern, and no exclusive cytoplasmic FOXP1 (c-FOXP1) staining was found. In ESCC, the expression rates of exclusive n-FOXP1-positive, exclusive c-FOXP1-positive, both nuclear and cytoplasmic positive and complete negative were 14.4%, 28.9%, 10.4% and 46.3%, respectively. High n-FOXP1 expression was significantly correlated with decreased postoperative recurrence and distant metastasis (P < 0.05). Furthermore, elevated c-FOXP1 expression was significantly associated with regional lymph node metastasis and distant metastasis (P < 0.05). High c-FOXP1 expression had an effect on shorter overall survival (OS) time, but the difference was not statistically significant (P > 0.05). Kaplan–Meier analysis showed that ESCC patients with high n-FOXP1 expression survived significantly longer than patients with low n-FOXP1 expression. Multivariate analysis confirmed that patients with high n-FOXP1 staining exhibit good prognosis and n-FOXP1 was an independent factor for ESCC prognosis.ConclusionsOur results suggest that FOXP1 plays an essential role in ESCC progression and prognosis and may be a useful biomarker for predicting survival.  相似文献   
59.
60.

Background

Previous studies suggest that dexmedetomidine has a protective effect against local anaesthetic-induced nerve injury in regional nerve blocks. Whether this potentially protective effect exists in the context of diabetes mellitus is unknown.

Methods

A diabetic state was established in adult male Sprague–Dawley rats with intraperitoneal injection of streptozotocin. Injections of ropivacaine 0.5%, dexmedetomidine 20 μg kg?1 (alone and in combination), or normal saline (all in 0.2 ml) were made around the sciatic nerve in control and diabetic rats (n=8 per group). The duration of sensory and motor nerve block and the motor nerve conduction velocity (MNCV) were determined. Sciatic nerves were harvested at post-injection day 7 and assessed with light and electron microscopy or used for pro-inflammatory cytokine measurements.

Results

Ropivacaine and dexmedetomidine alone or in combination did not produce nerve fibre damage in control non-diabetic rats. In diabetic rats, ropivacaine induced significant nerve fibre damage, which was enhanced by dexmedetomidine. This manifested with slowed MNCV, decreased axon density, and decreased ratio of inner to outer diameter of the myelin sheath (G ratio). Demyelination, axon disappearance, and empty vacuoles were also found using electron microscopy. An associated increase in nerve interleukin-1β and tumour necrosis factor-α was also seen.

Conclusions

Ropivacaine 0.5% causes significant sciatic nerve injury in diabetic rats that is greatly potentiated by high-dose dexmedetomidine. Although the dose of dexmedetomidine used in this study is considerably higher than that used in clinical practice, our data suggest that further studies to assess ropivacaine (alone and in combination with dexmedetomidine) use for peripheral nerve blockade in diabetic patients are warranted.  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