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   4711篇
  免费   232篇
  国内免费   62篇
耳鼻咽喉   68篇
儿科学   79篇
妇产科学   93篇
基础医学   629篇
口腔科学   111篇
临床医学   437篇
内科学   818篇
皮肤病学   151篇
神经病学   327篇
特种医学   256篇
外科学   585篇
综合类   38篇
一般理论   3篇
预防医学   251篇
眼科学   69篇
药学   608篇
中国医学   110篇
肿瘤学   372篇
  2023年   31篇
  2022年   114篇
  2021年   183篇
  2020年   91篇
  2019年   118篇
  2018年   148篇
  2017年   108篇
  2016年   141篇
  2015年   196篇
  2014年   257篇
  2013年   280篇
  2012年   389篇
  2011年   404篇
  2010年   226篇
  2009年   171篇
  2008年   273篇
  2007年   259篇
  2006年   230篇
  2005年   193篇
  2004年   166篇
  2003年   146篇
  2002年   107篇
  2001年   98篇
  2000年   81篇
  1999年   85篇
  1998年   50篇
  1997年   30篇
  1996年   44篇
  1995年   20篇
  1994年   19篇
  1993年   21篇
  1992年   36篇
  1991年   33篇
  1990年   32篇
  1989年   34篇
  1988年   26篇
  1987年   21篇
  1986年   7篇
  1985年   22篇
  1984年   8篇
  1983年   9篇
  1982年   8篇
  1979年   5篇
  1975年   7篇
  1974年   8篇
  1972年   5篇
  1971年   8篇
  1969年   6篇
  1968年   14篇
  1967年   5篇
排序方式: 共有5005条查询结果,搜索用时 15 毫秒
101.
AimsThe complement system, and especially C5a, plays an important role in the pathophysiology of renal diseases and post-transplant renal injury. The two receptors for C5a are C5a receptor (C5aR) and C5a-like-receptor-2 (C5L2). Only renal C5aR expression has been reported, although exact localization and alterations in expression after transplantation are unknown.Materials and resultsRenal C5aR and C5L2 expression and localization were analyzed immunohistochemically. C5aR and C5L2 expression was analyzed in human kidney biopsies obtained from living donors and patients suffering from acute tubular necrosis, acute cellular and vascular rejection or IF/TA.C5aR was expressed in the thick ascending limb of Henle's loop and first part of the distal convoluted tubule (DCT). Under inflammatory conditions, C5aR was de novo expressed in proximal tubuli. C5L2 was expressed in the kidney and localized to DCT1, DCT2 and connecting tubule. Persistent distal tubular expression of both receptors was demonstrated after renal transplantation.ConclusionsThis study shows distinct renal expression patterns for C5aR and C5L2. Our findings suggest a functional role for renal C5L2 rather than being a C5a decoy receptor. Future studies focusing on renal C5a–C5aR interaction should take differential C5aR and C5L2 expression into account, alongside abundant C5aR expression on infiltrating cells.  相似文献   
102.
103.
104.
Social inequality in adverse birth outcomes has been demonstrated in several countries. The present study examined the separate and joint effects of parental education and work in order to investigate the causal pathways of social class effects on adverse birth outcomes in Korea. The occurrence of low birth weight, preterm births, and intrauterine growth retardation was examined among 7,766,065 births in Korea from 1995 to 2008. The effect of social inequality, as represented by parental education and work, was examined against adverse birth outcomes using multivariate logistic regression after controlling for other covariates. Parental education had the most significant and greatest effect on all three adverse outcomes, followed by parental work and employment, which had lesser effects. For adverse birth outcomes, the gap between educational levels increased steadily in Korea from 1995 to 2008. Throughout the analysis, the effect of maternal manual work on adverse birth outcomes was apparent in the study results. Given this evidence of social inequality in education and employment, social interventions should aim at more in-depth and distal determinants of health.  相似文献   
105.
Although the number of studies using tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) for the treatment of high-risk pediatric solid tumors has been increasing, documentation of hematologic recovery after tandem HDCT/autoSCT is very limited. For this reason, we retrospectively analyzed the hematologic recovery of 236 children with high-risk solid tumors who underwent tandem HDCT/autoSCT. The median numbers of CD34+ cells transplanted during the first and second HDCT/autoSCT were 4.3 × 106/kg (range 0.6-220.2) and 4.1 × 106/kg (range 0.9-157.6), respectively (P = 0.664). While there was no difference in neutrophil recovery between the first and second HDCT/autoSCT, platelet and RBC recoveries were significantly delayed in the second HDCT/autoSCT (P < 0.001 and P < 0.001, respectively). Delayed recovery in the second HDCT/autoSCT was more prominent when the number of transplanted CD34+ cells was lower, especially if it was < 2 × 106/kg. A lower CD34+ cell count was also associated with increased RBC transfusion requirements and a higher serum ferritin level after tandem HDCT/autoSCT. More CD34+ cells need to be transplanted during the second HDCT/autoSCT in order to achieve the same hematologic recovery as the first HDCT/autoSCT.  相似文献   
106.
PURPOSEThis study aimed to evaluate the effect of repeated use of an implant handpiece under an implant placement torque (35 Ncm) and overloading torque condition (50 Ncm) on an output torque.MATERIALS AND METHODSTwo types of implant handpiece systems (Surgicpro/X-DSG20L [NSK, Kanuma, Japan] and SIP20/CRB46LN [SAESHIN, Daegu, South Korea]) were used. The output torque was measured using a digital torque gauge. The height and angle (x, y, and z axes) of the digital torque gauge and implant handpiece were adjusted through a jig for passive connection. The experiment was conducted under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150). For statistical analysis, the difference between the groups was analyzed using the Mann-Whitney U test and the Friedman test was used to confirm the change in output torque (α=.05).RESULTSNSK and SAESHIN implant handpieces showed significant differences in output torque results at the setting torques of 35 Ncm and 50 Ncm (P<.001). The type of implant handpiece and repeated use influenced the output torque (P<.001).CONCLUSIONThere may be a difference between the setting torque and actual output torque due to repeated use, and the implant handpiece should be managed and repaired during long-term use. In addition, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.  相似文献   
107.
Differential artery-vein (AV) analysis is essential for retinal study, disease detection, and treatment assessment. This study is to characterize vascular reflectance profiles and blood flow patterns of retinal artery and vein systems in optical coherence tomography (OCT) and OCT angiography (OCTA), and establish them as robust signatures for objective AV classification. A custom designed OCT was employed for three-dimensional (3D) imaging of mouse retina, and corresponding OCTA was reconstructed. Radially resliced OCT B-scans revealed two, i.e. top and bottom, hyperreflective wall boundaries in retinal arteries, while these wall boundaries were absent in OCT of retinal veins. Additional OCTA analysis consistently displayed a layered speckle distribution in the vein, which may indicate the venous laminar flow. These OCT and OCTA differences offer unique signatures for objective AV classification in OCT and OCTA.  相似文献   
108.
BackgroundAssessing pain of critically ill patients with brain injuries who are unable to communicate is a challenge. Current behavioral scales are limited in accurate pain assessments for this population.AimsThis study sought to investigate the behavioral and physiological responses induced by routine painful procedures in patients with brain injuries who are unable to communicate.MethodsUsing a repeated-measure within-subject observational study design, 12 participants admitted to an intensive care unit were observed before, during, and 15 minutes after a nonnociceptive (noninvasive blood pressure measurement) procedure and three nociceptive (suctioning, turning, and trapezius pinch) procedures. During each assessment, patients’ behavioral and physiological responses were observed using video cameras and bedside monitors.ResultsIn the overall behavioral responses to the nociceptive procedures, clenched teeth with tense jaw, frowning, orbit tightening, closing of eyes, eye movement, fixation-staring, flushing, flexion withdrawal of arm, flexion withdrawal of leg, muscle rigidity, twitching, and coughing were more frequently observed during procedures than before and after procedures (p < .01). Regarding physiological responses, significant increases in systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, and respiratory rate were identified across assessments (p < .001).ConclusionsThe findings can be used as a basis for pain assessment and the development of pain assessment tools for brain-injured patients who are unable to communicate. However, since physiological responses may be influenced by various factors besides pain, physiological changes may be used as a sign of the need for pain assessment rather than being used alone as a basis for pain assessment.  相似文献   
109.
ObjectiveWe described the technique of ultrasound (US)-guided percutaneous removal of the foreign bodies (FB) with hydro-dissection in the radiologic department and presented video files of several cases.ResultsThe mean time required for the entire procedure was approximately 20 minutes. There were no significant complications during the US-guided removal or long-term complications after the procedure. All 4 FBs were successfully removed from the soft tissue under US guidance.ConclusionUltrasound-guided percutaneous removal of the FBs with hydro-dissection in the radiology department is a less invasive and safe method over surgical removal in the operating room. Additionally, the use of a guide wire and serial dilator may help minimize soft tissue injury and facilitate the introduction of forceps.  相似文献   
110.
We measured heating of isotonic saline by three fluid warmers in six experiments: saline at 5 °C or 20 °C delivered at 30, 50 or 100 ml.min?1. At the three flow rates, the enFLOW®, buddy lite? and ThermoSens® systems heated 5 °C saline to mean (SD) temperatures of: 41.1 (0.5) °C, 37.7 (0.6) °C and 39.1 (0.6) °C; to 40.3 (0.8) °C, 33.9 (1.6) °C and 39.3 (0.7) °C; and to 37.1 (0.8) °C, 24.0 (1.3) °C and 37.6 (1.0) °C, respectively, p < 0.0001 for each experiment. The mean (SD) times taken to heat 5 °C saline were: 16.6 (1.7) s, 258.4 (58.9) s and 134.2 (79.6) s; 16.9 (1.8) s, 256.2 (62.2) s and 182.5 (74.5) s; and 21.5 (1.5) s, 275.9 (49.3) s and 313.5 (18.0) s, respectively, p < 0.0003 for each experiment. The results for saline at 20 °C were similar. The enFLOW system heated saline above 36 °C faster than the ThermoSens system, whereas the buddy lite often failed to achieve 36 °C.  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