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   18954篇
  免费   1973篇
  国内免费   795篇
耳鼻咽喉   201篇
儿科学   740篇
妇产科学   225篇
基础医学   4262篇
口腔科学   201篇
临床医学   1777篇
内科学   3183篇
皮肤病学   487篇
神经病学   1121篇
特种医学   292篇
外国民族医学   6篇
外科学   876篇
综合类   2635篇
现状与发展   6篇
一般理论   1篇
预防医学   1557篇
眼科学   419篇
药学   1108篇
  15篇
中国医学   281篇
肿瘤学   2329篇
  2024年   31篇
  2023年   299篇
  2022年   484篇
  2021年   793篇
  2020年   874篇
  2019年   778篇
  2018年   648篇
  2017年   739篇
  2016年   793篇
  2015年   841篇
  2014年   1230篇
  2013年   1373篇
  2012年   1117篇
  2011年   1159篇
  2010年   960篇
  2009年   1001篇
  2008年   1042篇
  2007年   1019篇
  2006年   964篇
  2005年   828篇
  2004年   748篇
  2003年   661篇
  2002年   558篇
  2001年   522篇
  2000年   384篇
  1999年   348篇
  1998年   275篇
  1997年   226篇
  1996年   156篇
  1995年   212篇
  1994年   149篇
  1993年   107篇
  1992年   66篇
  1991年   77篇
  1990年   49篇
  1989年   32篇
  1988年   28篇
  1987年   19篇
  1986年   13篇
  1985年   23篇
  1984年   19篇
  1983年   10篇
  1982年   15篇
  1981年   15篇
  1980年   15篇
  1979年   6篇
  1978年   3篇
  1977年   5篇
  1976年   3篇
  1970年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Genomic research in hematological malignancies has focused far more prominently on somatic mutations than on germline variants. Although increasing numbers of germline variants are being identified, a substantial proportion of familial myeloid malignancies have no causal allele pinpointed. Here we review the biological, technological, and clinical challenges that stand in the way of the goal of establishing, implementing, and interpreting a comprehensive panel of germline variants for testing. Achieving this goal would inform care for large numbers of myeloid malignancy patients. Furthermore, knowledge of germline susceptibility variants and their corresponding genes will shed light on disease processes, potentially suggesting therapeutic strategies tailored to specific variants.  相似文献   
102.
目的探讨电设备应用策略管理对层流手术室PM2.5及切口感染的影响。方法将200例患者按是否实施层流手术室电设备应用策略管理分为两组,每组100例。对照组采用层流手术室电设备常规管理,管理组在对照组基础上采用层流手术室电设备应用策略管理,统计两组术中手术室内人员数、手术时间、术中出血量、术后切口感染发生情况,检测患者切口及口鼻周围PM2.5浓度。结果两组术中手术室内人员数、手术时间、术中出血量比较差异无统计学意义(P>0.05)。管理组距离切口1 cm、5 cm、10 cm、20 cm和距离患者口鼻5 cm处PM2.5浓度显著低于对照组(P<0.01),切口感染率显著低于对照组(P<0.05)。切口感染患者距离切口1 cm、5 cm、10 cm、20 cm和距离患者口鼻5 cm处PM2.5浓度显著高于无切口感染患者(P<0.05)。相关分析显示,层流手术室PM2.5浓度与切口感染率呈显著正相关(P<0.05)。结论电设备应用策略管理有助于降低层流手术室PM2.5浓度及切口感染发生率。  相似文献   
103.
104.
In the present article we examine clonality in virus evolution. Most viruses retain an active recombination machinery as a potential means to initiate new levels of genetic exploration that go beyond those attainable solely by point mutations. However, despite abundant recombination that may be linked to molecular events essential for genome replication, herein we provide evidence that generation of recombinants with altered biological properties is not essential for the completion of the replication cycles of viruses, and that viral lineages (near-clades) can be defined. We distinguish mechanistically active but inconsequential recombination from evolutionarily relevant recombination, illustrated by episodes in the field and during experimental evolution. In the field, recombination has been at the origin of new viral pathogens, and has conferred fitness advantages to some viruses once the parental viruses have attained a sufficient degree of diversification by point mutations. In the laboratory, recombination mediated a salient genome segmentation of foot-and-mouth disease virus, an important animal pathogen whose genome in nature has always been characterized as unsegmented. We propose a model of continuous mutation and recombination, with punctuated, biologically relevant recombination events for the survival of viruses, both as disease agents and as promoters of cellular evolution. Thus, clonality is the standard evolutionary mode for viruses because recombination is largely inconsequential, since the decisive events for virus replication and survival are not dependent on the exchange of genetic material and formation of recombinant (mosaic) genomes.  相似文献   
105.
106.
107.
108.
This study aimed to compare the differences in characteristics and prognoses between Asian and white patients receiving immunotherapy for nonsmall cell lung cancer (NSCLC). We studied 390 patients who received atezolizumab as part of the POPLAR or OAK trial, and analyzed the differences in baseline characteristics, outcomes and genetic mutations in blood samples between Asian and white patients. Overall survival (OS) was longer in Asian compared to white patients (median OS: 18.7 vs. 11.1 months; p = 0.005). Race was identified as an independent prognostic factor for OS (Asian vs. white: hazard ratio 0.647, 95% confidence interval 0.447–0.936, p = 0.021), together with performance status, histology, baseline sum of the longest tumor diameters (BLSLD) and number of metastatic sites. The two groups also differed in terms of characteristics including smoking history, BLSLD, epidermal growth factor receptor (EGFR) mutation frequency, programmed death-ligand 1 expression and blood-based tumor-mutation burden. Blood mutations of STK11, EGFR, KEAP1, POLE, GRM3, ATM and STAG2 were associated with treatment response, and TP53, KEAP1, APC, RB1, CREBBP, EPHA5 and STAG2 mutations were associated with OS. The blood-based mutation profiles differentiated between Asian and white patients, especially in relation to EGFR (23.8 vs. 8.5%), TP53 (30.2 vs. 46.9%) and STK11 (1.6 vs. 12.3%) mutations (all p < 0.05). The different clinicopathological features and mutation profiles in Asian and white patients may explain the superior outcome following atezolizumab treatment in Asian patients with NSCLC. The results of this study have important implications for further studies on racial disparities in relation to immunotherapy.  相似文献   
109.
基于五运六气理论,尤其是三年化疫理论,对当前正在流行的新型冠状病毒感染的肺炎进行病因病机分析及分期诊疗指导。  相似文献   
110.
In subjects older than 50 years, the presence of clinical risk factors (CRFs) for fractures or a recent fracture is the cornerstone for case finding. In patients who are clinically at high short- and long-term risk of fractures (those with a recent clinical fracture or with multiple CRFs), further assessment with bone mineral density (BMD) measurement using dual-energy absorptiometry (DXA), imaging of the spine, fall risk evaluation and laboratory examination contributes to treatment decisions according to the height and modifiability of fracture risk. Treatment is available with anti-resorptive and anabolic drugs, and from the start of treatment a lifelong strategy is needed to decide about continuous, intermittent, and sequential therapy. Implementation of guidelines requires further initiatives for improving case finding, public awareness about osteoporosis and national policies on reimbursement of assessment and therapy.  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