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   27585篇
  免费   2650篇
  国内免费   779篇
耳鼻咽喉   149篇
儿科学   547篇
妇产科学   358篇
基础医学   2857篇
口腔科学   452篇
临床医学   2033篇
内科学   3206篇
皮肤病学   715篇
神经病学   2142篇
特种医学   1253篇
外国民族医学   10篇
外科学   1813篇
综合类   3725篇
现状与发展   3篇
一般理论   1篇
预防医学   4258篇
眼科学   875篇
药学   2734篇
  17篇
中国医学   1256篇
肿瘤学   2610篇
  2023年   401篇
  2022年   449篇
  2021年   1067篇
  2020年   982篇
  2019年   955篇
  2018年   922篇
  2017年   972篇
  2016年   1082篇
  2015年   1100篇
  2014年   1711篇
  2013年   2060篇
  2012年   1756篇
  2011年   1995篇
  2010年   1569篇
  2009年   1346篇
  2008年   1338篇
  2007年   1400篇
  2006年   1165篇
  2005年   966篇
  2004年   899篇
  2003年   829篇
  2002年   679篇
  2001年   667篇
  2000年   518篇
  1999年   399篇
  1998年   340篇
  1997年   334篇
  1996年   283篇
  1995年   254篇
  1994年   286篇
  1993年   225篇
  1992年   215篇
  1991年   196篇
  1990年   163篇
  1989年   181篇
  1988年   139篇
  1987年   132篇
  1986年   98篇
  1985年   153篇
  1984年   113篇
  1983年   87篇
  1982年   100篇
  1981年   90篇
  1980年   80篇
  1979年   67篇
  1978年   56篇
  1977年   49篇
  1976年   39篇
  1975年   20篇
  1973年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Mixed lineage leukemia 1(MLL1)是组蛋白甲基转移酶SET家族的成员之一。MLL1与WDR5、RbBP5、Ash2L和DPY-30组成MLL1甲基转移酶复合物调控组蛋白H3的第4位赖氨酸的甲基化水平,对造血系统的发育和血细胞的更新至关重要。部分白血病患者体内存在因MLL1基因易位而产生的致癌蛋白——MLL1融合蛋白,MLL1融合蛋白在发挥其致癌作用时需要功能完整的MLL1酶复合物,故靶向MLL1-WDR5的蛋白-蛋白相互作用成为治疗MLL1融合型白血病的潜在策略。本文对MLL1-WDR5蛋白-蛋白相互作用的生物学机制、结构信息以及抑制剂进行了系统的总结,并结合已报道数据对该领域进行了展望,以期为后续研究提供参考。  相似文献   
3.
4.
Background: Considering the poor prognosis of non-small cell lung cancer (NSCLC), the objective of this study was to examine the potential of plasma-derived vesicles as a source of lung cancer-specific proteins. Extracellular vesicle (EV) cargos are specific to the source cells, hence they have the potential of being a source of cancer-specific proteins.  Methods: The proteins differently expressed in cancer were determined and derived from EVs isolated from the plasma of NSCLC patients at the National Lung Hospital. To this end, purification was done using gel filtration chromatography and ultracentrifugation. In addition, nano liquid chromatography mass spectrometry (LC–MS/MS) was used for analyzing. Results: Fifty-seven EV-derived proteins related to NSCLC were highlighted in this research. Some of them have not been addressed before, such as EEF1A1 (elongation factor 1-α1), KPNB1 (Importin subunit beta 1), SRC (proto-oncogene tyrosine-protein kinase) and ACTC1 (actin, alpha cardiac muscle 1). This list was further confirmed through a comparison with ExoCarta and Vesiclepedia. Conclusion: This study is the first work to show the involvement of several novel proteins of small EV (EEF1A1, KPNB1, SRC, and ACTC1) in the progression of NSCLC. The results suggested that they could serve as novel biomarkers for non-small cell lung cancer in the future.  相似文献   
5.
6.
BackgroundAdjuvant chemotherapy, postoperative radiation (PORT), and prophylactic cranial irradiation (PCI) have been individually examined in limited-stage small cell lung cancer (SCLC). There is a paucity of data on the effectiveness of each adjuvant treatment modality when used in combination after surgical resection of SCLC.MethodsData were collected from 5 cancer centers on all patients with limited-stage SCLC who underwent surgical resection between 1986 and 2019. Univariate and multivariable models were conducted to identify predictors of long-term outcomes, focusing on freedom from recurrence and survival benefit of adjuvant chemotherapy, PORT, and PCI.ResultsA total of 164 patients were analyzed. Multivariable Cox regression analysis did not identify any adjuvant therapies to significantly influence recurrence in this cohort. Specifically, PORT was not associated with a significant influence on locoregional recurrence and PCI was not significantly associated with intracranial outcomes. Adjuvant chemotherapy improved survival in all stage I through III disease (hazard ratio, 0.49; 95% confidence interval, 0.29-0.81; P = .005) and even in pathologically node negative patients (hazard ratio, 0.49; 95% confidence interval, 0.27-0.91; P = .024). Although PCI was found to improve survival in univariate analysis, it was not significant in a multivariable model. PORT was not found to affect survival on either univariate or multivariable analysis.ConclusionsThis is among the largest multi-institutional studies on surgically resected limited-stage SCLC. Our results highlight survival benefit of adjuvant chemotherapy, but did not identify a statistically significant influence from mediastinal PORT or PCI in our cohort. Larger prospective studies are needed to determine the benefit of PORT or PCI in a surgically resected limited-stage SCLC population.  相似文献   
7.
IntroductionBrain metastases (BMs) occur in 40% of patients with lung cancer. The activity of immunotherapy in these patients, however, remains controversial, as the cornerstone treatment is radiotherapy (RT). Because RT is associated with adverse events that may impair the quality of life, the possibility of substituting it with a single systemic approach is attractive. Therefore, we performed a systematic review and meta-analysis to evaluate the potential benefit of immune checkpoint inhibitors (ICIs) in patients with NSCLC with untreated BM (unBM).MethodsStudies that enrolled patients with NSCLC treated with ICIs and specifically allowed for unBM were identified by searching the EMBASE, PubMed, Cochrane, and other databases. The outcomes evaluated were intracerebral overall response rate (icORR) and intracerebral disease control rate (icDCR) for unBM, and grades 3 and 4 toxicity rate.ResultsWe included 12 studies with a total of 566 individuals in the final analysis. Anti–programmed cell death protein-1 therapy seems to be active in the central nervous system, with an icORR of 16.4% (95% confidence interval [CI]: 9.8%–24%; I2 = 33.17%) and an icDCR of 45% (95% CI: 33.4%–56.9%; I2 = 46.91%). In the meta-analysis for icORR (risk ratio = 1.26, 95% CI: 0.57–2.79) and icDCR (risk ratio = 0.88, 95% CI: 0.55–1.43) we did not observe any difference among patients with BM who were treated with RT before ICI start and those who were treated with ICI only.ConclusionsICI seems to be effective as a single treatment for active BM in selected patients with advanced NSCLC.  相似文献   
8.
目的研究小细胞肺癌(SCLC)患者外周血中辅助性T细胞1(Th1)、Th2、Th17及调节性T淋巴细胞(Treg)的表达情况,探讨其在SCLC进展中的作用。方法选择2016年1月至2018年4月本院收治的44例住院的SCLC患者(SCLC组)及24名健康者(对照组)作为研究对象。采用流式细胞法检测两组研究对象外周血中Th1、Th2、Th17及Treg细胞的表达情况,应用微量样本多指标流式蛋白定量技术(CBA)检测血清中的细胞因子IFN-γ、IL-17及IL-10的表达情况。结果SCLC组患者的外周血中Th1细胞、Th1/Th2、IFN-γ表达水平显著低于对照组,差异具有统计学意义(P<0.01)。SCLC组患者的外周血中Th2、Treg、Th17、Treg/Th17、IL-17、IL-10表达水平显著高于对照组,差异具有统计学意义(P<0.01)。结论SCLC患者外周血中Th1/Th2的降低、Treg/Th17的升高可能与SCLC的致病机理及预后密切相关,该结论将为SCLC的治疗提供新的思路。  相似文献   
9.
Cerebral arterial pulsatility is strongly associated with cerebral small vessel disease and lacunar stroke yet its dependence on central versus local haemodynamic processes is unclear. In a population-based study of patients on best medical managment, 4–6 weeks after a TIA or non-disabling stroke, arterial stiffness and aortic systolic, diastolic and pulse pressures were measured (Sphygmocor). Middle cerebral artery peak and trough flow velocities and Gosling’s pulsatility index were measured by transcranial ultrasound. In 981 participants, aortic and cerebral pulsatility rose strongly with age in both sexes, but aortic diastolic pressure fell more with age in men whilst cerebral trough velocity fell more in women. There was no significant association between aortic systolic or diastolic blood pressure with cerebral peak or trough flow velocity but aortic pulse pressure explained 37% of the variance in cerebral arterial pulsatility, before adjustment, whilst 49% of the variance was explained by aortic pulse pressure, arterial stiffness, age, gender and cardiovascular risk factors. Furthermore, arterial stiffness partially mediated the relationship between aortic and cerebral pulsatility. Overall, absolute aortic pressures and cerebral blood flow velocity were poorly correlated but aortic and cerebral pulsatility were strongly related, suggesting a key role for transmission of aortic pulsatility to the brain.  相似文献   
10.
随着人口老龄化进程的加速,脑小血管病(CSVD)的发病率也在不断上升,其导致的多种症状严重影响了患者的生活质量。MRI弥散张量成像(DTI)作为新近发展的影像技术,有无创显示白质纤维超微结构等优点,已被广泛用于疾病早期诊断、病情预测、治疗评估等多方面的研究。本文即就DTI技术在CSVD中的研究现状和未来发展前景进行综述。  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