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   3855篇
  免费   339篇
  国内免费   82篇
耳鼻咽喉   43篇
儿科学   102篇
妇产科学   104篇
基础医学   511篇
口腔科学   82篇
临床医学   346篇
内科学   889篇
皮肤病学   45篇
神经病学   123篇
特种医学   105篇
外科学   443篇
综合类   291篇
现状与发展   1篇
一般理论   3篇
预防医学   313篇
眼科学   113篇
药学   278篇
中国医学   76篇
肿瘤学   408篇
  2023年   30篇
  2022年   16篇
  2021年   111篇
  2020年   83篇
  2019年   114篇
  2018年   95篇
  2017年   81篇
  2016年   102篇
  2015年   103篇
  2014年   131篇
  2013年   170篇
  2012年   252篇
  2011年   259篇
  2010年   146篇
  2009年   121篇
  2008年   172篇
  2007年   178篇
  2006年   204篇
  2005年   198篇
  2004年   230篇
  2003年   283篇
  2002年   252篇
  2001年   191篇
  2000年   127篇
  1999年   96篇
  1998年   46篇
  1997年   45篇
  1996年   28篇
  1995年   26篇
  1994年   19篇
  1993年   15篇
  1992年   47篇
  1991年   31篇
  1990年   32篇
  1989年   45篇
  1988年   16篇
  1987年   23篇
  1986年   18篇
  1985年   12篇
  1984年   14篇
  1983年   11篇
  1982年   10篇
  1981年   6篇
  1978年   8篇
  1976年   7篇
  1974年   7篇
  1973年   13篇
  1970年   5篇
  1969年   5篇
  1968年   5篇
排序方式: 共有4276条查询结果,搜索用时 15 毫秒
1.
ObjectiveTo evaluate differences in postoperative pain control and opioids requirement in thoracic surgical patients following implementation of an Enhanced Recovery after Thoracic Surgery protocol with a comprehensive postoperative pain management strategy.Material and MethodsA retrospective analysis of a prospectively maintained database of patients undergoing pulmonary resections by robotic thoracoscopy or thoracotomy from January 1, 2017, to January 31, 2019, was conducted. Multimodal pain management strategy (opioid-sparing analgesics, infiltration of liposomal bupivacaine to intercostal spaces and surgical sites, and elimination of thoracic epidural analgesia use in thoracotomy patients) was implemented as part of Enhanced Recovery after Thoracic Surgery on February 1, 2018. Outcome metrics including patient-reported pain levels, in-hospital and postdischarge opioids use, postoperative complications, and length of stay were compared before and after protocol implementation.ResultsIn total, 310 robotic thoracoscopy and 62 thoracotomy patients met the inclusion criteria. This pain management strategy was associated with significant reduction of postoperative pain in both groups with an overall reduction of postoperative opioids requirement. Median in-hospital opioids use (morphine milligram equivalent per day) was reduced from 30 to 18.36 (P = .009) for the robotic thoracoscopy group and slightly increased from 15.48 to 21.0 (P = .27) in the thoracotomy group. More importantly, median postdischarge opioids prescribed (total morphine milligram equivalent) was significantly reduced from 480.0 to 150.0 (P < .001) and 887.5 to 150.0 (P < .001) for the thoracoscopy and thoracotomy groups, respectively. Similar short-term perioperative outcomes were observed in both groups before and following protocol implementation.ConclusionsImplementation of Enhanced Recovery after Thoracic Surgery allows safe elimination of epidural use, better pain control, and less postoperative opioids use, especially a drastic reduction of postdischarge opioid need, without adversely affecting outcomes.  相似文献   
2.
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.  相似文献   
3.
4.
Objective

To evaluate the relationship between compliance check violations, and characteristics of the tobacco retailer and neighborhood social vulnerability in Oklahoma.

Design

This cross-sectional study utilized the US Food and Drug Administration (FDA) Compliance Check Inspections of Tobacco Product Retailers database for 2015–2019. These data were combined with Neighborhood social vulnerability variables using the Centers for Disease Control and Prevention (CDC) Social Vulnerability Index.

Setting

The setting of this study is the state of Oklahoma, USA.

Outcome measures

The outcome variable for this analysis was whether a sale was made to the youth during the compliance check (e.g., violation; yes/no) regardless of the outcome of the violation, and number of violations per a retailer.

Results

We observed a strong association between having a violation and retailer store type, after controlling for socioeconomic vulnerability and percentage of mobile homes. The proportion of a tobacco retailer’s violations also varied by store type.

Conclusions

More targeted enforcements and retailer education by store type may be necessary to increase compliance.

  相似文献   
5.
目的探讨超敏C反应蛋白(hs-CRP)与自发性脑出血患者(SICH)血肿量和预后的相关性。方法选取2016-01-2018-10萍乡市人民医院收治的SICH患者162例。将其分为大量血肿组、小量血肿组,选择同时期江西萍乡市人民医院80例门诊体检者为对照组。检测和比较3组入院时hs-CRP水平,比较预后良好和不良患者的hs-CRP水平,评价血清hs-CRP水平与血肿体积、预后的相关性。结果大量及小量血肿组hs-CRP水平显著高于对照组(P<0.01),且大量血肿组hs-CRP水平显著高于小量血肿组(P<0.05)。预后良好组hs-CRP水平显著低于预后不良组(P<0.05)。SICH患者hs-CRP水平与血肿量大小和GOS评分呈正相关(r=0.452,0.433,P<0.05)。结论SICH患者血清hs-CRP水平显著升高,与血肿量大小和预后明显相关。  相似文献   
6.
Background: H. pylori infection may play a role in the development of colorectal cancers (CRC). We aimed to examine the association between H. pylori infection and the risk of CRC by anatomical locations. Methods: We conducted a case-control study on 91 incidence cases of CRC and 224 hospital controls. CRC was determined by histopathological examinations. H. pylori IgG antibody in serum was tested. We collected data on the diet, nutrition, and lifestyle by the validated semi-quantitative food frequency and demographic lifestyle questionnaire. The odds ratio and 95% confidence interval (OR (95%CI) were estimated for CRC and its subgroups. Results: Overall 54.95% of CRC cases and 42.41% of the controls were H. pylori-seropositive, OR (95%CI): 1.56 (0.88, 2.74), p for trend=0.115. Positive dose-response association in quartiles, highest vs lowest, was observed for total CRC, OR (95%CI): 2.14 (1.00, 4.58), p for trend=0.049, for proximal colon, OR (95%CI): 1.52 (0.37, 6.25), p for trend=0.571), and for distal colon and rectum cancers combined, OR (95%CI): 2.38 (1.03, 5.50), p for trend=0.039. Conclusions: There is a positive association between H. pylori and colorectal cancers, especially distal colon and rectum cancers combined, but additional research is needed to determine the underlying mechanism of chronic H. pylori infection-induced CRC in humans.  相似文献   
7.
8.
9.
10.
The plasma cell malignancy multiple myeloma (MM) is unique among haematological malignancies in its capacity to cause osteoclast‐mediated skeletal destruction. The PI3K/Akt/mTOR pathway mediates proliferation, survival and drug resistance in MM plasma cells and is also involved in regulating the formation and activity of bone‐forming osteoblasts and bone‐resorbing osteoclasts. NVP‐BEZ235 is a dual pan class I PI3K and mTOR inhibitor that is currently undergoing clinical evaluation in several tumour settings. In this study, we examined the anti‐tumorigenic effects of BEZ235 in an immunocompetent mouse model of MM and assessed the effects of BEZ235 on osteoblast and osteoclast formation and function. BEZ235 treatment (50 mg/kg) resulted in a significant decrease in serum paraprotein and tumour burden, and μCT analysis of the proximal tibia revealed a significant reduction in the number of osteolytic bone lesions in BEZ235‐treated animals. Levels of the serum osteoblast marker P1NP were significantly higher in BEZ235‐treated animals, while levels of the osteoclast marker TRAcP5 were reduced. In vitro, BEZ235 decreased MM plasma cell proliferation, osteoclast formation and function and promoted osteoblast formation and function. These findings suggest that, in addition to its anti‐tumour properties, BEZ235 could be useful in treating osteolytic bone disease in MM patients.  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