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   15718篇
  免费   1181篇
  国内免费   76篇
耳鼻咽喉   108篇
儿科学   463篇
妇产科学   369篇
基础医学   2353篇
口腔科学   290篇
临床医学   1546篇
内科学   3572篇
皮肤病学   317篇
神经病学   1693篇
特种医学   547篇
外国民族医学   1篇
外科学   1515篇
综合类   161篇
现状与发展   1篇
一般理论   10篇
预防医学   1511篇
眼科学   220篇
药学   1014篇
中国医学   43篇
肿瘤学   1241篇
  2024年   28篇
  2023年   233篇
  2022年   433篇
  2021年   790篇
  2020年   465篇
  2019年   643篇
  2018年   689篇
  2017年   484篇
  2016年   522篇
  2015年   509篇
  2014年   709篇
  2013年   861篇
  2012年   1253篇
  2011年   1325篇
  2010年   722篇
  2009年   615篇
  2008年   868篇
  2007年   936篇
  2006年   820篇
  2005年   771篇
  2004年   710篇
  2003年   643篇
  2002年   581篇
  2001年   108篇
  2000年   95篇
  1999年   121篇
  1998年   113篇
  1997年   106篇
  1996年   90篇
  1995年   84篇
  1994年   63篇
  1993年   47篇
  1992年   46篇
  1991年   48篇
  1990年   35篇
  1989年   43篇
  1988年   35篇
  1987年   25篇
  1986年   33篇
  1985年   24篇
  1984年   32篇
  1983年   32篇
  1982年   20篇
  1981年   21篇
  1980年   25篇
  1979年   16篇
  1978年   17篇
  1977年   7篇
  1976年   10篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Thoracoamniotic shunting for fetal pleural effusions with hydrops   总被引:14,自引:0,他引:14  
OBJECTIVE: The purpose of this study was to evaluate perinatal outcome after thoracoamniotic shunting for fetal pleural effusions with hydrops. STUDY DESIGN: This was a retrospective study. RESULTS: Shunting was performed immediately after diagnosis and was successful in all 54 of the cases that were attempted. There were 7 pregnancy terminations, 9 in utero deaths, and 38 live births, of which 7 children died in the neonatal period and 31 children survived. Among the liveborn infants, 27 infants were delivered preterm (71%), of whom 7 infants (15%) had preterm premature rupture of membranes and 4 infants (8.5%) had chorioamnionitis. Perinatal death (23/54 infants; 43%) was related to underlying anomalies (7 cases), pulmonary hypoplasia (5 cases), chorioamnionitis (2 cases), or treatment failure for unknown reasons (9 cases). All 31 survivors had chylothorax; for 28 of the survivors, the chylothorax was primary, and for 3 survivors, the chylothorax was the result of right congenital diaphragmatic hernia, pulmonary sequestration, or Noonan syndrome. CONCLUSION: After the shunting, pleural effusion with hydrops has a 57% survival rate; premature delivery is the leading source of morbidity.  相似文献   
993.
Five cases of sirenomelia presented with rare manifestations are discussed. Three neonates were born alive and died within 2 to 12 hours after birth. One case was the offspring of a triple in vitro fertilization pregnancy with history of early intrauterine death of one of the triplets. The main features included fusion of lower extremities (five of five), renal agenesis (three of five), polycystic renal dysplasia (two of five), anal atresia with large bowel hypoplasia (three of five), pulmonary hypoplasia (four of five), and single umbilical artery (five of five). Other features that have only rarely been associated with sirenomelia included concurrence of congenital heart disease and neuroblastoma, gallbladder agenesis, and upper extremity defects.  相似文献   
994.
995.
This article focuses on the important role of the school nurse in promoting healthy lifestyle choices through networking, resource identification, and working with community partners. "Everyone Is Healthy at Northeast" was a health promotion program designed and presented in two ways: classroom lessons and a health fair. There were interactive health promotion classroom lessons on topics such as proper hand washing, the effects of tobacco, and keeping one's heart healthy. These lessons were enhanced by community partners in delivering the healthy lifestyle message through a variety of teaching methods: music, interactive games, and hands-on visuals. The health promotion education program culminated in a schoolwide health fair that showcased the healthy lifestyle choice information at various stations. "Everyone Is Healthy at Northeast" was a success and promoted healthy lifestyle choices through creativity, collaboration, and support from the entire school community.  相似文献   
996.
The automatic implantable defibrillators (AID) are increasingly used for both secondary and primary prevention of sudden cardiac death (SCD) in high risk adult cardiac patients with sustained ventricular arrhythmias (SVA) and/or significant ventricular dysfunction. The corresponding experience with AIDs in pediatric and young adult population is limited suggesting at least the same benefit as in the adult population. With the growing number of adults with previous corrective surgery of complex congenital heart disease (CHD), a need to address the risk stratification process for SCD among these patients is becoming increasingly important. For the present time, the AIDs have been mostly utilized for the secondary prevention of SCD in those postoperative CHD adult patients with a history of SVA. Currently available data on how to assess the risk for SCD among such patients as well as implications about the potential to prevent SCD with an earlier use of AID in this growing population are presented and discussed.  相似文献   
997.
To assess the accuracy of a computer-assisted computed tomography image analysis program in determining the location and volume of periacetabular osteolysis, we designed an osteolysis model by implanting bilateral total hip replacements in human pelvic cadavers and creating osteolytic lesions of varying sizes. The volumes of 48 defects were measured physically, and axial computed tomography scans were obtained. The computed tomography images were processed with streak artifact reduction and segmentation algorithms. The location and volume of lesions were determined from these images. Eighty-one percent (39 lesions) were identified correctly from the computed tomography scans. Detection was location-dependent. More lesions were detected in the ilium (100%) and at the rim (89%) than in the ischium (78%) or the pubis (50%). Computed tomography overestimated lesion volume by a mean of 0.5 +/- 2.3 cm. The volumetric error was unrelated to lesion location but was dependent on lesion size. As lesion size increased above 10 cm, the mean percentage error decreased to 1.8%. Computed tomography image analysis can be used more accurately than plain radiographs to investigate the effectiveness of treatment and the natural history of pelvic osteolysis.  相似文献   
998.
McConnell KA  Zou KH  Chabrerie AV  Bailey NO  Black PM 《Neurosurgery》2004,55(3):582-92; discussion 592-3
OBJECTIVE: This retrospective study examined whether changes in ventricular volume correspond with changes in adjustable valve pressure settings in a cohort of patients who received shunts to treat idiopathic normal pressure hydrocephalus. We also examined whether these pressure-volume curves and other patient variables would co-occur with a positive clinical response to shunting. METHODS: We selected 51 patients diagnosed with idiopathic normal pressure hydrocephalus who had undergone implantation of a Codman Hakim programmable valve (Medos S.A., Le Locle, Switzerland). Clinical data were gathered from the patients' records and clinical notes by an investigator blinded to patients' ventricular volumes. Ventricular volume was measured using 3D Slicer, an image analysis and interactive visualization software package developed and maintained at the Surgical Planning Laboratory at Brigham and Women's Hospital. RESULTS: Eighty-six percent of patients with gait disturbance at presentation showed improvement of this symptom, 70% experienced improvement in incontinence, and 69% experienced improvement in dementia. For the group showing 100% clinical improvement, the correlation coefficient of average changes in valve pressure over time (delta P/delta T) and average changes in ventricular volume over time (delta V/delta T) were high at 0.843 (P < 0.05). For the group experiencing no or only partial improvement, the correlation coefficient was 0.257 (P = 0.32), indicating no correlation between average delta V/delta T and average delta P/delta T for each patient. CONCLUSION: This was a carefully analyzed modeling study of idiopathic normal pressure hydrocephalus treatment made possible only by adjustable valve technology. With careful volumetric analysis, we found that changes in ventricular volume correlated with adjustments in valve pressure settings for those patients who improved clinically after shunting. This suggests that positive clinical responders retained parenchymal elasticity, emphasizing the importance of dynamic changes in this cohort.  相似文献   
999.
1000.
OBJECTIVE: The objective of our study was to prospectively evaluate whether a second-generation sonography contrast agent (SonoVue) can improve the conspicuity of solid organ injuries (liver; spleen; or kidney, including adrenal glands) in patients with blunt abdominal trauma. SUBJECTS AND METHODS: Two hundred ten consecutive hemodynamically stable trauma patients underwent both abdominal sonography and CT at admission. The presence of solid organ injuries and the quality of sonography examinations were recorded. Patients with false-negative sonography findings for solid organ injuries in comparison with CT results underwent control sonography. If a solid organ injury was still undetectable, contrast-enhanced sonography was performed. Findings of admission, control, and contrast-enhanced sonograms were compared with CT results for their ability to depict solid organ injuries. Contrast-enhanced sonography was also performed in patients in whom a vascular injury (pseudoaneurysm) was shown on admission or control CT. RESULTS: CT findings were positive for 88 solid organ injuries in 71 (34%) of the 210 patients. Admission, control, and contrast-enhanced sonograms had a detection rate for solid organ injury of 40% (35/88), 57% (50/88), and 80% (70/88), respectively. The improvement in the detection rate between control and contrast-enhanced sonography was statistically significant (p = 0.001). After exclusion of low-quality examinations, contrast-enhanced sonography still missed 18% of solid organ injuries. Five vascular liver (n = 1) and spleen (n = 4) injuries (pseudoaneurysms) were detected on CT; all were visible on contrast-enhanced sonography. CONCLUSION: Contrast-enhanced sonography misses a large percentage of solid organ injuries and cannot be recommended to replace CT in the triage of hemodynamically stable trauma patients. However, contrast-enhanced sonography could play a role in the detection of pseudoaneurysms.  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