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   5110篇
  免费   191篇
  国内免费   35篇
耳鼻咽喉   161篇
儿科学   66篇
妇产科学   367篇
基础医学   669篇
口腔科学   28篇
临床医学   323篇
内科学   1561篇
皮肤病学   72篇
神经病学   427篇
特种医学   98篇
外科学   425篇
综合类   56篇
预防医学   226篇
眼科学   75篇
药学   468篇
中国医学   10篇
肿瘤学   304篇
  2023年   35篇
  2022年   203篇
  2021年   283篇
  2020年   99篇
  2019年   128篇
  2018年   122篇
  2017年   97篇
  2016年   120篇
  2015年   123篇
  2014年   178篇
  2013年   276篇
  2012年   370篇
  2011年   401篇
  2010年   200篇
  2009年   149篇
  2008年   291篇
  2007年   343篇
  2006年   346篇
  2005年   351篇
  2004年   353篇
  2003年   300篇
  2002年   230篇
  2001年   21篇
  2000年   20篇
  1999年   26篇
  1998年   28篇
  1997年   29篇
  1996年   21篇
  1995年   20篇
  1994年   16篇
  1993年   14篇
  1992年   9篇
  1991年   10篇
  1990年   12篇
  1989年   10篇
  1988年   8篇
  1987年   7篇
  1986年   9篇
  1985年   11篇
  1984年   8篇
  1983年   9篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1973年   5篇
  1972年   5篇
  1971年   3篇
  1970年   4篇
  1967年   6篇
  1966年   3篇
排序方式: 共有5336条查询结果,搜索用时 0 毫秒
91.
Since February, 1980 nearly 200 automatic cardioverter - defibrillators have been implanted in patients with malignant ventricular arrhythmias. The currently-employed device weighs 298 grams and occupies a volume of 162 cm3. There are two defibrillation electrodes which also serve as sensors: one, an intravascular catheter placed in the superior vena cava at the level of the right atrium; the other, a flexible rectangular patch placed extrapericardially over the apex of the heart. Additionally, there is a bipolar right ventricular electrode for rate counting and R-wave synchronization which will eventually be used for pacing as well. The unit is powered by lithium batteries with a projected monitoring life of three years, or the capability of discharging approximately 100 times. The arrhythmia detector activates the cardioverter -defibrillator about 15 to 20 seconds after diagnosing a "treatable" arrhythmia, identified on the basis of a striking absence of isoelectric potential segments characteristic of ventricular fibrillation and many ventricular tachycardias. The diagnosis also requires fulfillment of individually-programmed heart rate criteria. If the initial discharge of 25 joules is ineffective, the device will recycle as many as three times with a final pulse of up to 42 joules. Of the twelve nonsurvivors among the initial 52 implantees who underwent implantation through September, 1982, only four deaths were unwitnessed and considered to be sudden and arrhythmic; the other eight deaths were due to heart failure or unrelated causes. Thus, from a predicted mortality of 48% in the same group of patients if the automatic defibrillator had not been implanted, the "sudden death" mortality was reduced to 8.5%.  相似文献   
92.
Obstructive sleep apnea and hypertension   总被引:4,自引:0,他引:4  
There is growing evidence of a causal relationship between obstructive sleep apnea (OSA) and hypertension. Untreated OSA may have direct and deleterious effects on cardiovascular function and structure through several mechanisms, including sympathetic activation, oxidative stress, inflammation, and endothelial dysfunction. OSA may contribute to or augment elevated blood pressure levels in a large proportion of the hypertensive patient population. It is important to consider OSA in the differential diagnosis of hypertensive patients who are obese. OSA should be especially considered in those hypertensive patients who respond poorly to combination therapy with antihypertensive medications.  相似文献   
93.
The electrocardiogram (ECG) interpretation in patients with implantable cardioverter defibrillator (ICD) is often a puzzling problem. The difficulty of the device function evaluation further increases in the presence of unfamiliar timing cycles and additional functions. We present an interesting ECG with a special function of a Biotronik ICD devices called the thoracic impedance monitoring, and demonstrate its behavior in a patient with atrial fibrillation, pacing beats, ventricular ectopic beats, and couple of ventricular beats. This report shows unexceptional occurrence of tricky ECG finding in patient with Biotronik ICDs.  相似文献   
94.
Single nucleotide polymorphisms (SNPs) of adhesion and signaling genes may influence the etiopathogenesis of multiple myeloma (MM). CD38 molecule and its ligand CD31 are expressed and interact in malignant plasma cells and MM microenvironment. In this study we evaluated allele frequencies and distribution of two potentially functional CD38 SNPs, intronic rs6449182 (184C>G) and missense rs1800561 (418C>T, Arg140Trp) in 175 Caucasian patients with MM and 207 healthy blood donors. The carriers of variant G allele of the rs6449182 SNPs were found to have significantly elevated risk of MM as compared to non-carriers; odds ratio = 5.69 (95% confidence interval = 3.7–8.7), p < 0.0001. In contrast, rs1800561 SNP minor T allele was detected at very low and comparable frequencies in patients and controls groups. In conclusion, our data suggest that inherited genetic variation in CD38 gene may impact on the risk of MM development.  相似文献   
95.
BackgroundCytomegalovirus (CMV) reactivation remains one of the most frequent complications after allogeneic hematopoietic stem cell transplantation (HSCT).MethodsAn analysis of the pre-transplant risk factors of CMV reactivation was performed in 98 patients aged 0.5–22 years (median 10.5) undergoing allogeneic HSCT. CMV reactivation was tested by assessing viral load using PCR method. Following factors were analyzed: type of conditioning, graft source, donor type, use of T-depletion and CMV-serostatus of the donor and recipient. Each factor was assigned from 0 to 2 points. Based on total score for each patient, CMV reactivation risk scale was developed, and two groups with low (LR) and high (HR) risk were determined.ResultsCMV reactivation was seen in 25 patients (24.5%). The significant risk factors for CMV reactivation were: CMV-positive recipient (p<0.001), unrelated donor (p<0.002), use of ATG (p<0.002) and PBSC (p<0,01). In the HR group the incidence of reactivation CMV was significantly higher than in LR group (47.8% vs. 5.4%, p<0.001).ConclusionsCMV seropositivity of the recipient was an independent predictor factor of CMV reactivation. The use of risk point scale of CMV reactivation allows for identification of patients with the higher risk of CMV reactivation.  相似文献   
96.
Forensic Toxicology - Cases of iron intoxication are not very often encountered in toxicology practice, and most of those reported concern accidental intoxications with iron supplements in young...  相似文献   
97.
Wu  Nan  Huang  Zhe  Shen  Yiqiu  Park  Jungkyu  Phang  Jason  Makino  Taro  Gene Kim  S.  Cho  Kyunghyun  Heacock  Laura  Moy  Linda  Geras  Krzysztof J. 《Journal of digital imaging》2021,34(6):1414-1423
Journal of Digital Imaging - Breast cancer is the most common cancer in women, and hundreds of thousands of unnecessary biopsies are done around the world at a tremendous cost. It is crucial to...  相似文献   
98.
99.
IntroductionPrimary arthroplasty of the hip joint is currently one of the most commonly performed procedures in orthopedics. In Poland we are observing significant changes in the age structure. With the prolonged life more and more elderly patients require musculoskeletal surgery to maintain comfortable and painless mobility. Reducing the duration of the procedure reduces the costs of anesthesiology, surgical and instrument teams, as well as the operating room technical team. The aim of the study was to compare the time required to perform hip joint arthroplasty by the direct anterior approach (DAA) with the postero-lateral approach (PLA) in our hospital.Material and methodsA retrospective analysis of 559 total and bipolar cemented and cementless hip replacement procedures based on two operative approaches – the minimally invasive DAA over the course of 2 years, and the standard PLA over the course of 3 years – was performed.ResultsStatistically significant differences were observed between the approaches used for cementless total arthroplasty with regard to the mean treatment times: 51.9 min for the 272 DAA cases, and 78.3 min for the 190 PLA cases (p < 0.0001). For the cementless hemi-arthroplasty procedure, the mean treatment times were 46.9 min in 36 patients for DAA, and 48.2 min for 61 patients for PLA (p = 0.57).ConclusionsMinimally invasive DAA significantly shortens the time of the procedure in elderly patients compared to PLA. Further study is needed to analyze other aspects of those two approaches.  相似文献   
100.
Acquired chromosome abnormalities in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are among the most valuable determinants of diagnosis and prognosis. In search of new recurrent balanced translocations, we reviewed the Cancer and Leukemia Group B (CALGB) cytogenetics database containing pretreatment and relapse karyotypes of 4,701 adults with AML and 565 with MDS who were treated on CALGB trials. We identified all cases with balanced structural rearrangements occurring as a sole abnormality or in addition to one other abnormality, excluded abnormalities known to be recurrent, and then reviewed the literature to determine whether any of what we considered unique, previously unknown abnormalities had been reported. As a result, we identified seven new recurrent balanced translocations in AML or MDS: t(7;11)(q22;p15.5), t(10;11)(q23;p15), t(2;12)(p13;p13), t(12;17)(p13;q12), t(2;3)(p21;p21), t(5;21)(q31;q22), and t(8;14)(q24.1;q32.2), and additionally, t(10;12)(p11;q15), a new translocation in AML previously reported in a case of acute lymphoblastic leukemia. Herein, we report hematologic and clinical characteristics and treatment outcomes of patients with these newly recognized recurrent translocations. We also report 52 unique balanced translocations, together with the clinical data of patients harboring them, which to our knowledge have not been previously published. We hope that once the awareness of their existence is increased, some of these translocations may become recognized as novel recurring abnormalities. Identification of additional cases with both the new recurrent and the unique balanced translocations will enable determination of their prognostic significance and help to provide insights into the mechanisms of disease pathogenesis in patients with these rare abnormalities. © 2012 Wiley Periodicals, Inc.  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