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   56483篇
  免费   3126篇
  国内免费   605篇
耳鼻咽喉   985篇
儿科学   664篇
妇产科学   826篇
基础医学   9793篇
口腔科学   1357篇
临床医学   4919篇
内科学   10617篇
皮肤病学   1887篇
神经病学   3987篇
特种医学   3020篇
外科学   7496篇
综合类   219篇
现状与发展   1篇
一般理论   17篇
预防医学   2739篇
眼科学   1246篇
药学   4998篇
中国医学   626篇
肿瘤学   4817篇
  2023年   428篇
  2022年   1328篇
  2021年   2062篇
  2020年   991篇
  2019年   1292篇
  2018年   1670篇
  2017年   1245篇
  2016年   1763篇
  2015年   2564篇
  2014年   3071篇
  2013年   3505篇
  2012年   5319篇
  2011年   4809篇
  2010年   2826篇
  2009年   2371篇
  2008年   3418篇
  2007年   3100篇
  2006年   2665篇
  2005年   2354篇
  2004年   2029篇
  2003年   1699篇
  2002年   1439篇
  2001年   1368篇
  2000年   1269篇
  1999年   914篇
  1998年   383篇
  1997年   263篇
  1996年   221篇
  1995年   196篇
  1994年   157篇
  1993年   143篇
  1992年   337篇
  1991年   322篇
  1990年   284篇
  1989年   272篇
  1988年   253篇
  1987年   261篇
  1986年   185篇
  1985年   175篇
  1984年   124篇
  1983年   113篇
  1982年   59篇
  1981年   62篇
  1979年   84篇
  1978年   68篇
  1975年   51篇
  1974年   61篇
  1973年   52篇
  1972年   51篇
  1970年   49篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The roles of Notch1 and Notch2 in T‐cell function have been well studied, but the functional roles of Notch in B cells have not been extensively investigated, except for Notch2 involvement in peripheral marginal zone B‐cell differentiation. This study examined the roles of Notch1 in murine primary B cells. During B‐cell activation by B‐cell receptor ligation, Notch1 was up‐regulated while Notch2 was not. In addition, Notch1 up‐regulation itself did not contribute to the further activation of B cells, but the Notch ligand was important for Notch1‐mediated further B‐cell activation. Moreover, Notch1 deficiency significantly decreased B‐cell activation and antibody secretion under the presence of Notch ligand. These data suggest that Notch1 is an important mediator for enhancing B‐cell activation and antibody secretion by Notch ligand.  相似文献   
992.
993.
The technology for measuring ECG using capacitive electrodes and its applications are reviewed. Capacitive electrodes are built with a high-input-impedance preamplifier and a shield on their rear side. Guarding and driving ground are used to reduce noise. An analysis of the intrinsic noise shows that the thermal noise caused by the resistance in the preamplifier is the dominant factor of the intrinsic noise. A fully non-contact capacitive measurement has been developed using capacitive grounding and applied to a non-intrusive ECG measurement in daily life. Many ongoing studies are examining how to enhance the quality and ease of applying electrodes, thus extending their applications in ubiquitous healthcare from attached-on-object measurements to wearable or EEG measurements.  相似文献   
994.
995.
Endovascular salvage of the hypogastric artery using iliac branch device (IBD) during endovascular aortic aneurysm repair (EVAR), offers less invasive alternative solution to surgery to prevent pelvic ischemia. We have performed the first Korean surgeon custom-made IBD for this purpose to overcome the limitation of unavailability of the devices in Korea. Four patients with abdominal aortic aneurysm with bilateral common iliac artery aneurysm (CIAA) were treated using custom-made IBDs from October 2013 to December 2013. IBD was created in back table before EVAR operation using TFLE Zenith iliac limb stent graft (Cook Inc.). Three V12 (Atrium, Inc.) one Viabahn (Gore, Inc.) were used for bridging between IBD and target hypogastric artery. With this modification of IBD procedure, exteriorize the guide wire without snare device is possible which offers another benefit in terms of reducing medical costs comparing to commercial IBD. All operations were successful without any device related complications or postoperative endoleaks. During the mean follow up of 3 months, all IBD were patent without clinical complications. Surgeon custom made IBD is feasible and useful to preserve pelvic perfusion especially in the situation of limited commercial IBD availability in many countries. Long-term follow-up is needed to evaluate stent graft patency and IBD-related complications.  相似文献   
996.
The aim of this study was to determine whether skin temperature measurement by digital thermography on hands and feet is useful for diagnosis of Raynaud''s phenomenon (RP). Fifty-seven patients with RP (primary RP, n = 33; secondary RP, n = 24) and 146 healthy volunteers were recruited. After acclimation to room temperature for 30 min, thermal imaging of palmar aspect of hands and dorsal aspect of feet were taken. Temperature differences between palm (center) and the coolest finger and temperature differences between foot dorsum (center) and first toe significantly differed between patients and controls. The area under curve analysis showed that temperature difference of the coolest finger (cutoff value: 2.2℃) differentiated RP patients from controls (sensitivity/specificity: 67/60%, respectively). Temperature differences of first toe (cutoff value: 3.11℃) also discriminated RP patients (sensitivity/specificity: about 73/66%, respectively). A combination of thermographic assessment of the coolest finger and first toe was highly effective in men (sensitivity/specificity : about 88/60%, respectively) while thermographic assessment of first toe was solely sufficient for women (sensitivity/specificity: about 74/68%, respectively). Thermographic assessment of the coolest finger and first toe is useful for diagnosing RP. In women, thermography of first toe is highly recommended.

Graphical Abstract

相似文献   
997.
Vertical transmission from mother to child, the main route of chronic hepatitis B virus (HBV) infection in the East Asia, is considered one of the most important predictors for the response to antiviral therapies as well as its complications such as cirrhosis and hepatocellular carcinoma. Therefore, it is critical in both etiologic and prognostic aspects to confirm whether or not chronic HBV infection is acquired vertically. This study investigated whether mother-to-child infection could be proved by the phylogenetic analyses of HBV pre-S/S genes ever since several decades have elapsed in mother-child pairs with presumed vertical transmission. The pre-S and S regions of HBVs were compared and analyzed phylogenetically in a total of 36 adults (18 mother-child pairs) with chronic HBV infection. All of the isolates of HBV were genotype C and serotype adr. The divergence between mothers and offsprings was 0 to 1.5%. Phylogenetic trees revealed that 17 of 18 pairs (94%) with presumed vertical transmission were grouped into the same cluster. Vertical transmission from mother to child could be strongly suggested even in adults with a history of several decades of HBV infection using the phylogenetic analyses of pre-S and S genes.

Graphical Abstract

相似文献   
998.
The object of this study was to evaluate the effect of uric acid lowering therapy in reducing the new development of comorbidities and the frequency of acute attacks in gout patients. We retrospectively reviewed patients who were diagnosed to have gout with at least 3 yr of follow up. They were divided into 2 groups; 53 patients with mean serum uric acid level (sUA)<6 mg/dL and 147 patients with mean sUA≥6 mg/dL. Comorbidities of gout such as hypertension (HTN), type II diabetes mellitus (DM), chronic kidney disease, cardiovascular disease (CVD) and urolithiasis were compared in each group at baseline and at last follow-up visit. Frequency of acute gout attacks were also compared between the groups. During the mean follow up period of 7.6 yr, the yearly rate of acute attack and the new development of HTN, DM, CVD and urolithiasis was lower in the adequately treated group compared to the inadequately treated group. Tight control of uric acid decreases the incidence of acute gout attacks and comorbidities of gout such as HTN, DM, CVD and urolithiasis.

Graphical Abstract

相似文献   
999.
This study was conducted to evaluate age-specific seroprevalence of pertussis in Korea and to formulate a strategy to prevent and reduce the incidence of pertussis. Residual serum samples of healthy adolescents and adults 11 yr of age or older were collected between July 2012 and December 2012, and anti-pertussis toxin (PT) IgG titers were measured using a commercial ELISA kit. We compared the mean anti-PT IgG titers and seroprevalence of pertussis of the six age groups: 11-20, 21-30, 31-40, 41-50, 51-60, and ≥ 61 yr. A total of 1,192 subjects were enrolled. The mean anti-PT IgG titer and pertussis seroprevalence were 35.53 ± 62.91 EU/mL and 41.4%, respectively. The mean anti-PT IgG titers and seroprevalence were not significantly different between the age groups. However, the seroprevalence in individuals 51 yr of age or older was significantly higher than in individuals younger than 51 yr (46.5% vs 39.1%, P = 0.017). Based on these results, a new pertussis prevention strategy is necessary for older adults.

Graphical Abstract

相似文献   
1000.
The rapid response system (RRS) is an innovative system designed for in-hospital, at-risk patients but underutilization of the RRS generally results in unexpected cardiopulmonary arrests. We implemented an extended RRS (E-RRS) that was triggered by actively screening at-risk patients prior to calls from primary medical attendants. These patients were identified from laboratory data, emergency consults, and step-down units. A four-member rapid response team was assembled that included an ICU staff, and the team visited the patients more than twice per day for evaluation, triage, and treatment of the patients with evidence of acute physiological decline. The goal was to provide this treatment before the team received a call from the patient''s primary physician. We sought to describe the effectiveness of the E-RRS at preventing sudden and unexpected arrests and in-hospital mortality. Over the 1-yr intervention period, 2,722 patients were screened by the E-RRS program from 28,661 admissions. There were a total of 1,996 E-RRS activations of simple consultations for invasive procedures. After E-RRS implementation, the mean hospital code rate decreased by 31.1% and the mean in-hospital mortality rate was reduced by 15.3%. In conclusion, the implementation of E-RRS is associated with a reduction in the in-hospital code and mortality rates.

Graphical Abstract

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