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   5441篇
  免费   481篇
  国内免费   333篇
耳鼻咽喉   31篇
儿科学   87篇
妇产科学   113篇
基础医学   700篇
口腔科学   119篇
临床医学   707篇
内科学   934篇
皮肤病学   80篇
神经病学   319篇
特种医学   181篇
外科学   703篇
综合类   749篇
现状与发展   2篇
一般理论   1篇
预防医学   283篇
眼科学   128篇
药学   515篇
  1篇
中国医学   202篇
肿瘤学   400篇
  2024年   16篇
  2023年   82篇
  2022年   192篇
  2021年   230篇
  2020年   181篇
  2019年   155篇
  2018年   200篇
  2017年   159篇
  2016年   167篇
  2015年   220篇
  2014年   275篇
  2013年   247篇
  2012年   399篇
  2011年   449篇
  2010年   243篇
  2009年   229篇
  2008年   290篇
  2007年   305篇
  2006年   256篇
  2005年   268篇
  2004年   207篇
  2003年   184篇
  2002年   145篇
  2001年   135篇
  2000年   138篇
  1999年   151篇
  1998年   94篇
  1997年   78篇
  1996年   70篇
  1995年   63篇
  1994年   51篇
  1993年   36篇
  1992年   52篇
  1991年   45篇
  1990年   41篇
  1989年   34篇
  1988年   28篇
  1987年   23篇
  1986年   23篇
  1985年   14篇
  1984年   14篇
  1983年   11篇
  1982年   6篇
  1981年   6篇
  1979年   10篇
  1973年   2篇
  1972年   4篇
  1971年   3篇
  1970年   6篇
  1969年   6篇
排序方式: 共有6255条查询结果,搜索用时 15 毫秒
51.
Purpose: Hyponatremia is a common electrolyte abnormality in a variety of medical conditions. Lower predialysis serum sodium concentration is associated with an increased risk of death in oligoanuric patients on hemodialysis. However, whether hyponatremia affects the short-term mortality in chronic peritoneal dialysis (CPD) patients remains unclear. Methods: We conducted a cross-sectional and two-year follow-up review retrospectively, and 318 patients with CPD were enrolled in a medical center. Serum sodium levels were measured at baseline and categorized as quartile of Na: quartile 1 (124–135?mEq/L), quartile 2 (136–139), quartile 3 (140–141) and quartile 4 (142–148). Mortality and cause of death were recorded for longitudinal analyses. Results: The patients with higher quartile (higher serum sodium) had a trend of lower age, peritoneal dialysis (PD) duration, co-morbidity index, D/P Cr and white blood cell counts and higher renal Kt/Vurea (Kt/V) and serum albumin level. Stepwise multiple linear regression analysis showed that serum sodium level was positively associated with albumin, residual renal Kt/V and negatively associated with age and PD duration in CPD patients. After two-year follow-up, stepwise multivariate Cox proportional hazards model demonstrated that age, co-morbidity index and serum albumin were the significant risk factors for all-cause two-year mortality, but not serum sodium levels. Conclusions: Serum sodium level in CPD patients is associated with nutritional status, residual renal function and duration of PD. However, baseline serum sodium level is not an independent predictor of two-year mortality in CPD patients.  相似文献   
52.
Ventricular assist devices (VAD) in children with terminal heart failure have been used as a bridge to transplantation or myocardial recovery for more than 20 years. The Berlin Heart Excor® Pediatric VAD is approved for use either as univentricular or biventricular support for children with a body weight less than 20 kg. Larger children can be supported with implantable continuous flow devices, e.g. HeartWare HVAD. Indications for support are cardiomyopathy, myocarditis and terminal heart failure in patients with congenital heart diseases. Due to the shortage of donors support time on VADs has greatly increased often lasting longer than 1 year. Although increased experience and technical modifications over the last decade have substantially improved the outcome of patients on VAD support, much is still dependent on the etiology of the heart failure. The survival rate in children with normal anatomy is approximately 80?% compared to 50?% in children with congenital heart diseases. The main complications during VAD support which occur in nearly 25?% of children weighing less than 20 kg are thromboembolic events. Miniaturization of the device to improve the quality of life for children on support and minimizing the risk of thromboembolic events are current fields of intensive research.  相似文献   
53.
目的探讨关节腔内注射氨甲环酸在减少全膝关节置换术后出血的疗效和安全性。方法选取符合纳入标准的患者60例,采用RandA1.0软件随机平均分为两组。氨甲环酸组于术后关节腔内注射50 ml溶有3.0 g氨甲环酸的生理盐水,夹闭引流管1 h后负压吸引;对照组则术后通过引流管直接向关节腔注入生理盐水50 ml,夹闭引流管1 h后负压吸引。术后三日每天复查患者血常规、凝血指标,并记录每日引流量,术后3~5 d行下肢静脉造影,观察血栓发生率。结果氨甲环酸组术后3 d总的引流量以及总失血量明显少于对照组。氨甲环酸组输血人数明显小于对照组。两组患者在术后凝血功能、血栓发生率及术后不良事件方面差异无统计学意义。结论全膝关节术后关节腔内注射氨甲环酸可有效减少出血量,并不增加血栓发生概率。  相似文献   
54.
目的 研究一组金黄色葡萄球菌临床分离株毒力基因和耐药基因的存在状况.方法 连续收集浙江省宁波市第一医院2013年7至9月临床分离的金黄色葡萄球菌共40株,采用聚合酶链反应(PCR)的方法分析42种毒力基因和11种耐药基因,再以10类毒力基因和1种耐药基因mecA检测结果作二元分型.结果 40株金黄色葡萄球对青霉素的敏感率为12.5% (5/40),对红霉素的敏感率为42.5%(17/40),对其余15种抗菌药物的敏感率均大于65.0%.除了人主要组织相容性复合体(M HC)类似蛋白编码基因map未检出,其他几类毒力基因:黏附素、细胞毒素、荚膜抗原、超抗原、丝氨酸蛋白酶均有检出,检出率为2.5%~100.0%.耐β-内酰胺类、氨基糖苷类、红霉素类、四环素类、季铵盐消毒剂、抗菌肽的耐药基因均有检出,检出率为2.5%~37.5%.40株菌株经二元分型可分为16种阳性基因检出模式,每株菌最少检出3类毒力基因,最多检出7类毒力基因和1类耐药基因mecA.结论 本组菌株耐药表型和耐药基因型符合率较高,菌株携带多种毒力基因和耐药基因.  相似文献   
55.
目的了解住院艾滋病亲属照顾者在看护期间内的主要压力源及负性心理体验。方法采用个人深度访谈法,收集8名照顾者的资料,用主题分析法进行分析,归纳住院艾滋病患者主要照顾者的压力源种类及其负性心理体验。结果照顾者压力源主要来源包括与艾滋病相关的压力源、与经济相关的压力源及与社会文化相关的压力源;照顾者的负性心理体验主要有怀疑、否认,恐惧、害怕,痛苦、矛盾,愤怒,迷茫无助及社交减少。结论住院艾滋病患者照顾者的压力源来源于多个方面,其负性心理体验复杂,研究者应重视主要照顾者的压力,为其提供有效的干预措施,加强支持系统。  相似文献   
56.

Background

Even after surgery, hepatocellular carcinoma (HCC) has poor prognosis; adjuvant therapy is needed to improve effectively the outcome of HCC patients. We evaluated the efficacy of cytokine-induced killer (CIK) cell infusion as an adjuvant therapy for postoperative HCC patients.

Methods

A total of 410 patients were studied retrospectively (January 2002 to January 2007): 206 received surgery alone; 204 received surgery and at least four cycles of CIK cell transfusion (CIK group). Kaplan–Meier and Cox regression analyses were used to explore differences in OS between two groups.

Results

The CIK group overall survival rates were significantly higher than that of the surgery-alone group (log-rank test; p = 0.0007). Multivariate survival analysis showed that CIK cell treatment was an independent prognostic factor. In subgroup analysis, patients who received ≥8 cycles of CIK cell transfusion exhibited significantly better survival than the <8 cycle group (p = 0.0272). There was no significant difference in overall survival in patients with ≤5-cm tumors between the CIK and surgery-alone groups (p = 0.7567). However, in patients with >5-cm tumors, the CIK group displayed significantly better overall survival than the surgery-alone group (p = 0.0002).

Conclusions

Postoperative immunotherapy with CIK cell transfusion may be an effective adjuvant treatment for improving the outcomes of HCC patients; >8 cycles of CIK cell transfusion may ensure that patients derive maximal benefits. Moreover, patients with large tumors might benefit more from CIK cell adjuvant treatment than patients with small tumors.  相似文献   
57.
Weng C  Tian W  Li ZY  Liu B  Li Q  Wang YQ  Sun YZ 《Spine》2012,37(21):1839-1846
STUDY DESIGN.: Retrospective case series. OBJECTIVE.: To evaluate the accuracy of screw fixation using intraoperative three-dimensional fluoroscopy-based navigation (ITFN) and to assess the clinical outcomes of this treatment regimen. SUMMARY OF BACKGROUND DATA.: The surgical management of symptomatic os odontoideum poses considerable difficulties due to the highly variable anatomy of the upper cervical spine and surrounding neurovascular structures. Various methods have been described for the treatment of symptomatic os odontoideum, all of which have limitations. METHODS.: Nineteen patients with symptomatic os odontoideum were investigated. Pain scores were assessed using the visual analogue scale. Myelopathy was assessed using the Nurick scale and Odom's criteria. Radiological imaging was carried out in all patients for diagnosis and to assess the atlantodens interval, space available for cord, and presence of intramedullary hyperintensity signals on T2-weighted images at the C1-C2 level. Posterior stabilization was performed for all patients by using ITFN. RESULTS.: The mean Nurick score improved from 2.3 before surgery to 0.7 at the time of follow-up. The mean follow-up period was 34.7 months (range, 12-65 mo). According to Odom's criteria, outcomes were as follows: excellent, 47%; good, 37%; fair, 11%; and poor, 5%. All patients with preoperative neck pain had symptom relief or improvement, with all of these patients having more than 83.7% improvement in visual analogue scale scores. The mean preoperative space available for cord value of 9.3 mm improved to 17.7 mm. Solid fusion and reduction of atlantoaxial dislocation were achieved in every patient without screw failure. Sixty screws were placed in 19 patients. Two C2 polyaxial screws in 2 patients and 1 transarticular screw in 1 patient slightly penetrated the transverse foramen with no vascular injury and clinical sequelae. CONCLUSION.: ITFN is a safe, accurate, and effective tool for screw placement in patients with symptomatic os odontoideum.  相似文献   
58.

Background

To establish quicker cardiac arrest and less myocardial distension injury during heart procurement, we combined St. Thomas and histidine-tryptophan-ketoglutarate (HTK) solutions for donor heart preservation since June 2008.

Methods

From June 2008 to March 2010, we enrolled 31 heart transplantation (HT) patients in this study. During heart procurement we initially infused 1,000 mL cold St Thomas cardioplegic solution to achieve cardiac arrest. After procurement, a further 2,000 mL of cold HTK solution was infused at low perfusion pressure. Another 1,000 mL cold HTK solution was perfused before donor heart implantation. We examined donor age, recipient preoperative characteristics, ischemia time, hospital stay, postoperative graft function, major cardiac events, and transplant vasculopathy (TCAD).

Results

Twenty-two patients (71.0%) presented with dilated cardiomyopathy and 7 (23.3%) with ischemia cardiomyopathy. There were 23 (76.7%) male donors, and the mean donor age was 38.4 ± 13.8 years. Six patients underwent a redo sternotomy, 1 patient needed a third-do sternotomy, and 1 a seventh sternotomy (third HT) for repeated endocarditis and graft failure. The average ischemia time was 224.9 ± 71.0 minutes and the postoperative hospital stay was 57.7 ± 47.7 days. The surgical mortality (3.2%) was not accompanied by hospital or follow-up mortality. Patient left ventricular ejection fraction postoperative was 59.6 ± 2.3% with good functional status. Major cardiac events occurred in 8 patients (26.7%) without major complications. There were two subjects with TCAD but normal graft function. The correlation between ischemia time and hospital stay was insignificant (r = 0.21; P = .26).

Conclusions

Donor heart preservation combining St Thomas cardioplegic arest and low-pressure perfusion with HTK solution seemed to be safe with. short-term survival similar to other approaches.  相似文献   
59.
目的对比观察封闭式负压引流技术(vacuum sealing drainage,VSD)联合反取皮和直接反取皮治疗开放性创伤截肢创面的疗效。方法 2005年3月-2010年6月,应用随机单盲法对收治的60例四肢开放性骨折截肢患者分别采用一期VSD联合反取中厚皮片植皮(试验组,30例)与一期单纯反取中厚皮片植皮覆盖截肢创面(对照组,30例)治疗。两组患者性别、年龄、致伤原因、截肢部位、皮肤缺损面积、术前白蛋白指数及受伤至就诊时间等一般资料比较差异均无统计学意义(P>0.05)。试验组截肢后剪除多余残肢皮肤应用皮鼓取皮制成中厚交错筛网状皮片,植于截肢创面,表面用VSD覆盖,24 h不间断吸引持续7~10 d;对照组截肢后直接行反取中厚皮片覆盖创面,术后常规换药。结果试验组患者于术后平均8 d去除VSD装置。试验组皮片存活率(90.0%)、创面感染率(3.3%)及再截肢率(0)、换药次数[(2.0±0.5)次]、住院时间[(12.0±2.6)d],均显著优于对照组[分别为63.3%、20.0%、13.3%、(8.0±1.5)次、(18.0±3.2)d],比较差异均有统计学意义(P<0.05)。两组患者均获随访,随访时间1~3年,平均2年。末次随访时,试验组瘢痕面积、瘢痕分级及创面两点辨别觉均优于对照组,差异有统计学意义(P<0.05)。两组患者残肢均未见明显肿胀;术后试验组患肢疼痛发生率、残肢长度均优于对照组(P<0.05),而患肢残端形状比较差异无统计学意义(P>0.05)。两组残肢与健侧相比较,均存在肌肉废用性萎缩、肌力下降,各组健侧与患侧肌力比较差异均有统计学意义(P<0.05),但两组患侧间比较差异无统计学意义(P>0.05)。结论与单纯反取中厚皮片比较,VSD联合反取中厚皮片能够一期关闭截肢创面并对创面进行引流,降低感染发生,促进皮片与创面良好贴附,提高了皮片存活率,降低了截肢平面,利于假肢佩戴,是一期处理截肢创面的理想方法之一。  相似文献   
60.
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