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   36395篇
  免费   2664篇
  国内免费   514篇
耳鼻咽喉   246篇
儿科学   485篇
妇产科学   466篇
基础医学   1816篇
口腔科学   268篇
临床医学   3155篇
内科学   4240篇
皮肤病学   522篇
神经病学   1371篇
特种医学   563篇
外国民族医学   1篇
外科学   2161篇
综合类   4046篇
预防医学   5807篇
眼科学   232篇
药学   11009篇
  14篇
中国医学   630篇
肿瘤学   2541篇
  2023年   447篇
  2022年   893篇
  2021年   1204篇
  2020年   1139篇
  2019年   1175篇
  2018年   1177篇
  2017年   1143篇
  2016年   1103篇
  2015年   1266篇
  2014年   2653篇
  2013年   3244篇
  2012年   2557篇
  2011年   2904篇
  2010年   2128篇
  2009年   1993篇
  2008年   2000篇
  2007年   1897篇
  2006年   1600篇
  2005年   1323篇
  2004年   1092篇
  2003年   894篇
  2002年   711篇
  2001年   628篇
  2000年   532篇
  1999年   517篇
  1998年   339篇
  1997年   305篇
  1996年   259篇
  1995年   241篇
  1994年   229篇
  1993年   187篇
  1992年   164篇
  1991年   122篇
  1990年   122篇
  1989年   98篇
  1988年   112篇
  1987年   105篇
  1986年   101篇
  1985年   114篇
  1984年   135篇
  1983年   69篇
  1982年   77篇
  1981年   53篇
  1980年   68篇
  1979年   51篇
  1978年   57篇
  1977年   52篇
  1976年   60篇
  1975年   65篇
  1974年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Many therapeutic options are now available for men with metastatic castration-resistant prostate cancer (mCRPC), including next-generation androgen receptor axis-targeted therapies (AATTs), immunotherapy, chemotherapy, and radioisotope therapies. No clear consensus has been reached for the optimal sequencing of treatments for patients with mCRPC, and few well-validated molecular markers exist to guide the treatment decisions for individual patients. The androgen receptor splice variant 7 (AR-V7), a splice variant of the androgen receptor mRNA resulting in the truncation of the ligand-binding domain, has emerged as a biomarker for resistance to AATT. AR-V7 expression in circulating tumor cells has been associated with poor outcomes in patients treated with second- and third-line AATTs. Clinically validated assays are now commercially available for the AR-V7 biomarker. In the present review of the current literature, we have summarized the biology of resistance to AATT, with a focus on the AR-V7; and the clinical studies that have validated AR-V7 expression as a strong independent predictor of a lack of clinical benefit from AATTs. Existing evidence has indicated that patients with AR-V7–positive mCRPC will have better outcomes if treated with taxane chemotherapy regimens rather than additional AATTs.  相似文献   
82.
《Clinical lung cancer》2020,21(3):232-237
BackgroundInsights into the mechanism of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) could provide important information for further patient management, including the choice of second-line treatment. The EGFR T790M mutation is the most common mechanism of resistance to first- and second-generation EGFR TKIs. Owing to its biologic relevance in the response of non–small-cell lung cancer (NSCLC) to the selective pressure of treatment, the present study investigated whether the occurrence of T790M at progression differed among patients receiving gefitinib, erlotinib, or afatinib.Patients and MethodsThe present retrospective study included patients with NSCLC with an EGFR activating mutation, who had received gefitinib, erlotinib, or afatinib as first-line treatment. Plasma samples for the analysis of cell-free DNA were taken at disease progression and analyzed using a digital droplet polymerase chain reaction EGFR mutation assay.ResultsA total of 83 patients were enrolled; 42 had received gefitinib or erlotinib and 41afatinib. The patient characteristics were comparable across the 2 groups. The median time to progression (TTP) was 14.4 months for the gefitinib and erlotinib group and 10.2 months for the afatinib group (P = .09). Of the 83 patients, 47 (56.6%) were positive for the T790M in plasma. A greater incidence of T790M was observed in patients with progression during gefitinib or erlotinib therapy compared with patients treated with afatinib (33 [79%] vs. 14 [34%], respectively; odds ratio, 7.1; 95% confidence interval, 2.7-18.5; P = .0001).ConclusionsAlthough gefitinib, erlotinib, and afatinib showed a comparable TTP in patients receiving first-line therapy, the incidence of T790M differed among them, as demonstrated by the present study, which could have implications for the choice of second-line treatment.  相似文献   
83.
As a powerful tool to advance drug discovery, molecular imaging may provide new insights into the process of drug effect and therapy at cellular and molecular levels. When compared with other detection methods, fluorescence-based strategies are highly attractive and can be used to illuminate pathways of drugs’ transport, with multi-color capacity, high specificity and good sensitivity. The conjugates of fluorescent molecules and therapeutic agents create exciting avenues for real-time monitoring of drug delivery and distribution, both in vitro and in vivo. In this short review, we discuss recent developments of small molecule-based fluorophore-drug conjugates, including non-cleavable and cleavable ones, that are capable of visualizing drug delivery.  相似文献   
84.
目的:目前青黛已是治疗急性幼粒细胞白血病(APL)的临床有效药物,但其分子机制与物质基础仍不明确。基于此本研究构建青黛与APL可视化药靶蛋白模型,以探究青黛作用于APL的分子机制。方法:通过GEO数据库检索APL微阵列芯片分析APL差异表达基因,使用TCMSP数据库筛选青黛活性成分,结合PubChem和SwissTargetPrediction匹配活性成分的靶基因并进行富集分析。String用于挖掘并构建APL可视化蛋白互作数据,将其读入Cytoscape,通过Centiscape实现网络拓扑分析。综合APL差异表达基因,通过Sybyl与青黛活性成分构建药靶蛋白模型。结果:筛选出3张APL微阵列芯片,164个差异表达基因,9种青黛活性成分,541个靶基因,这些靶点较多地参与细胞凋亡、药物结合、癌症途径、慢性粒细胞白血病等,这些都在APL中起重要作用。拓扑分析显示ELANE,CTSS为核心基因,将其与青黛9种活性成分进行药靶蛋白模型预测,显示靛玉红和靛蓝与核心基因结合度最佳。结论:APL是受多基因调控的复杂疾病,而青黛成分中靛玉红和靛蓝可通过结合ELANE,CTSS作用于APL的发生发展。  相似文献   
85.
86.
The relationship between man and substances that have abuse potentials, and whose use has been associated with the development or progression of substance use disorders has continued to evolve in terms of geography, economic implications, and time. History shows that local plants with psychoactive constituents can get exported worldwide through global travel, commerce, or even conquest. Time and globalization also change people’s relationship with substances of abuse; hence, an area that was initially alien to certain substances might evolve to becoming a trafficking hub, and then a destination. A case in point is Africa where a rapidly increasing prevalence of substance use/abuse and substance use disorder among adolescents and young adults is putting enormous strain on the economy, healthcare system, and society at large. However, there appears to be a paucity of scientific literature and data on the epidemiology, risk assessment, and contributing factors to substance use and the development of substance use disorders across Africa. In this narrative review, we examine extant literature (PubMed, Google scholar, Medline) for information on the prevalence, trends, and influencers of substance use and the development of substance use disorders. This is with a view of understanding the determinants of substance use and factors that influence the development of substance use disorders in the region, and how this information can be channeled towards developing a comprehensive intervention and treatment program.  相似文献   
87.
Breast cancer is one of the leading causes of cancer-related deaths in women worldwide. It is a cancer that originates from the mammary ducts and involves mutations in multiple genes. Recently, the treatment of breast cancer has become increasingly challenging owing to the increase in tumor heterogeneity and aggressiveness, which gives rise to therapeutic resistance. Epidemiological, population-based, and hospital-based case-control studies have demonstrated an association between high intake of certain Allium vegetables and a reduced risk in the development of breast cancer. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are the main allyl sulfur compounds present in garlic, and are known to exhibit anticancer activity as they interfere with breast cancer cell proliferation, tumor metastasis, and angiogenesis. The present review highlights multidrug resistance mechanisms and their signaling pathways in breast cancer. This review discusses the potential anticancer activities of DADS and DATS, with emphasis on drug resistance in triple-negative breast cancer (TNBC). Understanding the anticancer activities of DADS and DATS provides insights into their potential in targeting drug resistance mechanisms of TNBC, especially in clinical studies.  相似文献   
88.
89.
社区获得性肺炎(Community Acquired Pneumonia,CAP)是比较常见的院外肺部炎性疾病之一,随着细菌、支原体、衣原体等多种病原体的耐药率的上升,以及病患梯度的范围增加,CAP的发病率呈逐年上升的趋势,死亡率日益增高,导致医疗资源消耗巨大。目前临床上CAP的患者主要依靠经验性治疗。正确选择抗生素、减少病原体的耐药率,优化肺部炎症疾病的医疗方案,提高CAP临床治愈率已经成为临床医生当前面临的一项重大挑战。中药制剂具有广谱抗菌、调节免疫、不易耐药、简便价廉等特点,是解决上述难题的一个很好途径。  相似文献   
90.
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