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   216427篇
  免费   57238篇
  国内免费   10231篇
耳鼻咽喉   2660篇
儿科学   6165篇
妇产科学   2074篇
基础医学   30907篇
口腔科学   7822篇
临床医学   31478篇
内科学   41842篇
皮肤病学   8849篇
神经病学   19398篇
特种医学   7109篇
外国民族医学   71篇
外科学   26567篇
综合类   29238篇
现状与发展   29篇
一般理论   31篇
预防医学   14995篇
眼科学   4842篇
药学   21901篇
  160篇
中国医学   10592篇
肿瘤学   17166篇
  2024年   394篇
  2023年   1990篇
  2022年   4542篇
  2021年   8259篇
  2020年   10343篇
  2019年   14923篇
  2018年   14452篇
  2017年   15624篇
  2016年   15956篇
  2015年   18299篇
  2014年   19922篇
  2013年   19740篇
  2012年   15415篇
  2011年   16828篇
  2010年   17423篇
  2009年   12300篇
  2008年   10586篇
  2007年   9328篇
  2006年   8970篇
  2005年   8082篇
  2004年   5603篇
  2003年   5348篇
  2002年   4567篇
  2001年   4082篇
  2000年   3822篇
  1999年   3381篇
  1998年   1922篇
  1997年   2008篇
  1996年   1486篇
  1995年   1309篇
  1994年   1110篇
  1993年   711篇
  1992年   858篇
  1991年   739篇
  1990年   618篇
  1989年   573篇
  1988年   464篇
  1987年   434篇
  1986年   355篇
  1985年   265篇
  1984年   177篇
  1983年   113篇
  1982年   74篇
  1981年   91篇
  1980年   62篇
  1979年   82篇
  1978年   33篇
  1977年   20篇
  1976年   25篇
  1974年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Background: Breast cancer (BC) is the most common malignant tumor in women, and its morbidity and mortality are increasing each year, due to the lack of specific clinical symptoms in the early stage of BC, and the lack of diagnostic methods for early breast cancer. Therefore, identifying an effective diagnostic method for early BC has become urgent. Materials and Methods: Breast lesions with a histological diagnosis that were examined by ultrasonic elastography (UE) in our department from June 2020 to December 2021 were reviewed. qRT-PCR was performed to measure the expression levels of miR-144-5p and miR-26b-5p in the plasma of patients with BC. The receiver operating characteristics (ROC) curve and area under the curve (AUC) were used to investigate the potential diagnostic value of miR- 144-5p, miR-26b-5p and the elastographic score in BC. Results: The ultrasonic elastography score(UES) was found to be significantly upregulated in BC compared with that in benign breast lesions, and the AUC, sensitivity and specificity were 0.809, 0.717 and 0.806 for distinguishing BC from benign breast lesions, respectively. miR-144-5p and miR-26b- 5p were found to be upregulated in the plasma of BC patients, and miR-144-5p+miR-26b-5p had 0.781 sensitivity and 0.780 specificity for the diagnosis of BC. Furthermore, we found that the diagnostic performance of miR-144-5p and miR-26b-5p combined with UES for BC had 0.913 sensitivity and 0.890 specificity. Conclusions: The combination of plasma miR-144-5p, miR-26b-5p and UES has a very high clinical application value for the early detection of BC.  相似文献   
2.
3.
目的分析细棒、PEEK棒固定对寰枢关节稳定性的影响。方法采用6具新鲜成人枕骨(occipital bone,Oc)~颈椎C4节段进行测试,模拟以下手术及固定状态:①完整状态;②损伤状态:枢椎齿状突II型骨折;③坚强固定:寰枢椎均采用普通椎弓根螺钉固定,直径3.5 mm钛棒连接;④PEEK棒:直径3.5 mm的PEEK棒连接;⑤细棒:直径2.0 mm钛棒连接。采用重复测量实验设计,在完整、损伤和不同的固定状态下,通过脊柱试验机对标本分别施加1.5 N·m的前屈/后伸、左/右侧弯和左/右轴向旋转的纯力偶矩。采用Optotrak三维运动测量系统连续采集标本运动,分析寰枢椎之间角度运动范围和中性区。结果采用直径3.5 mm的钛棒,2.0 mm的细棒以及3.5 mm的PEEK棒固定后,在前屈、后伸、侧弯和旋转方向上均显著减小了固定节段的运动范围(P<0.05)。直径3.5 mm和2.0 mm的棒固定后的运动范围,在各个方向上无显著性差异。PEEK棒固定的运动范围仅在侧弯方向上大于坚强固定(P=0.005),其他方向无显著性差异。3种固定方式在屈伸、侧弯和旋转方向上均显著减小了固定节段的中性区(P<0.05)。各种固定方式之间相比较,无显著性差异(P>0.05)。结论在寰枢关节采用直径2.0 mm的细棒固定,与坚强固定的稳定性相当。采用直径3.5 mm的PEEK棒固定,在前屈、后伸、旋转方向上与坚强固定的稳定性相当,在侧弯方向上弱于坚强固定。  相似文献   
4.
5.
ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.  相似文献   
6.
Bone mineral density (BMD) is a highly heritable predictor of osteoporotic fracture. GWAS have identified hundreds of loci influencing BMD, but few have been functionally analyzed. In this study, we show that SNPs within a BMD locus on chromosome 14q32.32 alter splicing and expression of PAR-1a/microtubule affinity regulating kinase 3 (MARK3), a conserved serine/threonine kinase known to regulate bioenergetics, cell division, and polarity. Mice lacking Mark3 either globally or selectively in osteoblasts have increased bone mass at maturity. RNA profiling from Mark3-deficient osteoblasts suggested changes in the expression of components of the Notch signaling pathway. Mark3-deficient osteoblasts exhibited greater matrix mineralization compared with controls that was accompanied by reduced Jag1/Hes1 expression and diminished downstream JNK signaling. Overexpression of Jag1 in Mark3-deficient osteoblasts both in vitro and in vivo normalized mineralization capacity and bone mass, respectively. Together, these findings reveal a mechanism whereby genetically regulated alterations in Mark3 expression perturb cell signaling in osteoblasts to influence bone mass.  相似文献   
7.
8.
PurposeThe purpose of this study was to make a systematic review and meta-analysis to determine the stent diameter (8 mm vs. 10 mm) that conveys better safety and clinical efficacy for transjugular intrahepatic portosystemic shunt (TIPS).Materials and methodsFour databases were used to identify clinical trials published from inception until March 2020. Data were extracted to estimate and compare one-year and three-year overall survivals, hepatic encephalopathy, variceal rebleeding, and shunt dysfunction rates between patients with 8 mm covered stents and those with 10 mm covered stents.ResultsFive eligible studies were selected, which included 489 patients (316 men, 173 women). The 8 mm covered stent group had higher efficacy regarding one-year or three-year overall survival (odds ratio [OR], 2.88; P = 0.003) and (OR, 1.81; P = 0.04) and lower hepatic encephalopathy (OR, 0.69; P = 0.04) compared with 10 mm covered stent group. There were no significant differences in variceal rebleeding rate (OR 0.80; P = 0.67). However, shunt dysfunction was lower in 10 mm covered stent group (OR, 2.26; P = 0.003).ConclusionsOur results suggest that the use of 8 mm covered stents should be preferred to that of 10 mm covered stents for TIPS placement when portal pressure is frequently monitored.  相似文献   
9.
Lessons Learned
  • The overall safety profiles of ipilimumab 3 mg/kg and 10 mg/kg administered every 3 weeks, were consistent between Chinese patients with solid tumors in the current study and patients from previous U.S. ipilimumab monotherapy studies. No new safety signals were identified.
  • The mean systemic exposures to ipilimumab (assessed by first dose area under the curve during the dosing interval and maximum serum concentration) were numerically lower in the Chinese patient population than in U.S. patients for both 3 mg/kg and 10 mg/kg doses; however, the range of serum concentrations in the Chinese and U.S. populations overlapped (3 mg/kg and 10 mg/kg), suggesting that ipilimumab pharmacokinetics was ethnically insensitive in this study.
BackgroundThis phase I, open‐label study assessed ipilimumab safety, tolerability, pharmacokinetics (PK), immunogenicity, and antitumor activity in Chinese patients with unresectable, metastatic, recurrent malignant melanoma (MM) or nasopharyngeal carcinoma (NPC).MethodsOf 39 patients enrolled, 25 received ipilimumab (11 patients received 3 mg/kg, and 14 patients received 10 mg/kg). Reasons for not receiving treatment were withdrawal of consent (3 patients), no longer meeting the criteria (10 patients), and one recorded as “other.” During the induction phase, patients received ipilimumab (3 mg/kg, i.v.), on day 1 of a 3‐week cycle, to a maximum of four doses or progressive disease (PD). During the maintenance phase at week 24, patients received ipilimumab (3 mg/kg, i.v.) on day 1 of a 12‐week cycle, to a maximum of 3 years or PD. Considering the co‐primary safety and PK endpoints, the successive dosing required nine patients with two or fewer dose‐limiting toxicities during the 42‐day observation period to proceed with a new cohort of nine patients at 10 mg/kg.ResultsIpilimumab safety and PK profiles were similar in Chinese and predominantly White populations. Ipilimumab was well tolerated. Most adverse events (AEs) were grades 1–2 and experienced by 11 patients treated with 3 mg/kg and 14 patients treated with 10 mg/kg. There were no new safety concerns. Incidence of anti‐ipilimumab antibodies was low (1 of 10 in the 3 mg/kg patients and 2 of 13 in the 10 mg/kg patients) and without safety implications. In the 3 mg/kg group, 8 of 11 patients had PD. In the 10 mg/kg group (all NPC, 0 MM patients), 11 of 14 patients had PD. Three patients had stable disease (one at 3 mg/kg and two at 10 mg/kg).ConclusionIpilimumab was well tolerated in Chinese patients, showing similar safety and PK to previous studies in predominantly White populations.  相似文献   
10.
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