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   227525篇
  免费   20104篇
  国内免费   14651篇
耳鼻咽喉   1975篇
儿科学   2226篇
妇产科学   2989篇
基础医学   27301篇
口腔科学   3756篇
临床医学   31631篇
内科学   33676篇
皮肤病学   2256篇
神经病学   12792篇
特种医学   8338篇
外国民族医学   138篇
外科学   22475篇
综合类   35939篇
现状与发展   55篇
一般理论   19篇
预防医学   13366篇
眼科学   6860篇
药学   23067篇
  253篇
中国医学   12733篇
肿瘤学   20435篇
  2025年   63篇
  2024年   3075篇
  2023年   4789篇
  2022年   9609篇
  2021年   11838篇
  2020年   9321篇
  2019年   8138篇
  2018年   8109篇
  2017年   7209篇
  2016年   6772篇
  2015年   10329篇
  2014年   12628篇
  2013年   10742篇
  2012年   16070篇
  2011年   17979篇
  2010年   10537篇
  2009年   8216篇
  2008年   11141篇
  2007年   11121篇
  2006年   11267篇
  2005年   11351篇
  2004年   7009篇
  2003年   6625篇
  2002年   5515篇
  2001年   4945篇
  2000年   5353篇
  1999年   5705篇
  1998年   3541篇
  1997年   3508篇
  1996年   2822篇
  1995年   2622篇
  1994年   2151篇
  1993年   1386篇
  1992年   1894篇
  1991年   1600篇
  1990年   1299篇
  1989年   1098篇
  1988年   1019篇
  1987年   892篇
  1986年   728篇
  1985年   526篇
  1984年   336篇
  1983年   242篇
  1982年   149篇
  1981年   145篇
  1980年   111篇
  1979年   143篇
  1977年   53篇
  1975年   57篇
  1974年   56篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
采用ICP-OES和原子荧光光度计分析了污泥及其焚烧灰渣中重金属的种类和浓度,并对灰渣中重金属的浸出毒性进行分析。结果表明污泥焚烧灰渣中重金属种类多、浓度高,可依据不同重金属的挥发性大小将污泥中重金属划分为极易挥发重金属、易挥发重金属、中等挥发重金属和难挥发重金属四大类,实际污染控制中应重点关注重金属Hg、As、Cd、Pb四种重金属的控制;同时,毒性浸出实验结果表明污泥焚烧之后灰渣中重金属稳定性得到极大提高,可直接进行填埋处理,但做建材使用时仍存在很大的浸出风险。  相似文献   
142.
Along with the vigorous development of medical science and other related subjects,a lot of new techniques,concepts,materials,and methods continuously sprung up.The techniques of plastic and cosmetic su...  相似文献   
143.
144.
145.

Purpose

To determine the role of dynamic cervical implant (DCI) replacement for single-level degenerative cervical disc disease in Chinese patients.

Methods

Thirty patients with single-level degenerative cervical disc disease were prospectively enrolled between April 2010 and August 2010 (12 women, 18 men; mean age 56.5 years). All patients underwent anterior cervical decompression, DCI replacement, clinical and radiological assessments preoperatively and at 1, 6, 12, and 24 months postoperatively, and Japanese Orthopaedic Association (JOA), Visual Analogue Scale (VAS), Neck Disability Index (NDI), and Short Form 36 (SF-36) scores. Lateral neutral radiographs provided the intervertebral space height. Lateral dynamic radiographs were taken to measure the range of motion (ROM) of the cervical spine and functional spinal unit (FSU) of the treated segment. We compared the amount of motion of the adjacent vertebral endplate and the intrinsic motion of the implant and calculated a correlation analysis.

Results

DCI showed good clinical and radiographic outcomes. At the final follow-up, JOA, VAS, NDI, and SF-36 average scores improved significantly. The intervertebral space height increased slightly after operation and was maintained during follow up. The ROM of the cervical spine and FSU decreased at early follow-up, but recovered to the preoperative level within 1–2 years. There was a high index of linear correlation between the motion of the adjacent vertebral endplate and the intrinsic motion of the implant.

Conclusions

DCI provided elastic dynamic stability for the targeted segment, and restored and sustained intervertebral space height and ROM of the cervical spine.  相似文献   
146.

Purpose

Since its introduction, the Da Vinci surgical system for the treatment of gastroesophageal reflux disease (GERD) has been the subject of much controversy. Several prospective randomized controlled trials, conducted to assess its effectiveness and safety, have revealed differences. We performed this meta-analysis to evaluate the efficiency and safety of robotic Nissen fundoplication for GERD.

Methods

We performed a comprehensive search of PubMed, Embase, and OVID-MEDLINE, from 1950 to the present, with daily updates generated by a computer, to identify all published papers on robotic Nissen fundoplication for the treatment of GERD. The meta-analysis was performed by Review Manager Version 5.0. Differences of the overall effect were considered significant at P < 0.05 with a 95 % confidence interval (95 % CI).

Results

Five studies with a collective total of 160 patients were included. Apart from intra-operative and post-operative complications, which were excluded because of incomplete primary data, there were no significant differences in outcomes, including of total operation interval (P = 0.16), effective operation interval (P = 0.95), post-operative dysphagia (P = 0.94), intra-operative conversion (P = 0.94), re-operation (P = 0.43), hospital stay (P = 0.97) and in-hospital costs (P = 0.08).

Conclusions

As current data do not clarify the advantages of the Da Vinci surgical system in Nissen fundoplication for GERD, we believe that a large a multi-center controlled trial is warranted.  相似文献   
147.

Objective

To explore the best entry point and trajectory of anterior cervical transpedicular screws in the lower cervical spine by radiological studies, and provide reference for clinical application.

Methods

Fifty patients were scanned by computed tomography and confirmed no obvious defect of the cervical spine. On horizontal axis, camber angle (α) and axial length (AL) were measured from C3 to C7. On sagittal view, the cranial or caudal angle (β) and sagittal length (SL) were also measured from C3 to C7. On the sagittal and horizontal planes vertebrae were respectively divided into four areas, ordered 1–4, on the anterior side of the pedicle. The areas and angles of pedicle intersect into the vertebral body were recorded. We inserted six anterior pedicle screws into the lower cervical spine of three patients by this technique.

Results

On transverse plane, camber angle (α) of C3–C5 increased gradually, while it decreased from C5 to C7. On sagittal view, C3 and C4 pedicles showed cranial tilting, while C5 to C7 were caudally tilted. AL and SL values increased gradually from C3 to C7. The number of the intersections of C3–C7 in each area was also different. Six pedicle screws of three cases were inserted into the lower cervical spine with proper placement and no complications.

Conclusion

Anterior transpedicular screw (ATPS) is a theoretically feasible option for internal fixation. The technique described in this paper was subsequently used in three patients without complication. Future improvement of ATPS insertion remains necessary for this technically demanding procedure.  相似文献   
148.
目的探讨新型咽鼓管吹张法对儿童分泌性中耳炎的治疗效果。方法将90例分泌性中耳炎患儿按照随机数字表分为对照组和观察组各45例。观察组采用新型咽鼓管吹张法治疗,对照组采用传统的波氏球咽鼓管吹张法治疗,观察记录治疗3个月后两组患儿声阻抗检测变化及患儿的舒适度。结果治疗3个月后两组患儿的声阻抗检测结果及舒适度比较,差异有统计学意义(P0.05,P0.01)。结论新型咽鼓管吹张法能提高患儿操作时的舒适度,增加患儿治疗的信心,提高疾病治疗效果。  相似文献   
149.
Objective To identify novel biomarker for diabetic nephropathy (DN) by urinary proteomic methods, and to detect the expression of E-cadherin in urine and renal tissue of patients with DN. Methods Urine samples were collected from 12 cases of type 1 diabetic nephropathy patients (T1DN), 12 cases of type 2 diabetic nephropathy patients (T2DN), 12 cases of nephritic syndrome patients (NS), and 12 cases of healthy Controls. Comparative proteomic approach of two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) were employed to identify DN-related biomarker in urine samples. The differential expression of the identified biomarker in urine samples and renal biopsy specimens were detected by Western blotting and immunohistochemistry method. Results E-cadherin was identified by 2DE/MS, which was significantly up-regulated in T1DN and T2DN groups (all P< 0.01). Western blotting confirmed the expression of E-cadherin was significantly higher in T1DN and T2DN groups than in NS and Control groups (all P<0.01). Immunohistochemical stain showed E-cadherin was mainly expressed in the membrane and cytoplasm of renal tubular epithelial cell, and its expression was markedly decreased in DN kidneys compared with healthy Controls (P<0.05). Conclusions E-cadherin is identified as a novel DN-related biomarker, which is specifically increased in urine of DN patients.  相似文献   
150.
目的探讨PICC置管患者携管出院期间的维护方法。方法静脉治疗团队将进修护士、肿瘤专科护士、静疗专科护士及静疗学习班学员纳入网络维护人员,逐步建立PICC维护网点并不断扩大规模,通过建立维护花名册、QQ群、专科护士返基地活动等措施进行管理。结果 PICC维护网络已覆盖到江苏省126所二、三级医院及安徽省3个市县的3所二、三级医院,参与PICC维护网点维护的护士达195人。携管出院患者导管相关并发症(静脉炎、导管堵塞、皮肤湿疹、渗液、非计划拔管)的总发生率由2008年的17.9%下降至2013年的3.5%;借助QQ群解决了近600例置管及维护疑难问题。结论 PICC维护网络的建立,满足了携管出院患者治疗间歇期间的导管维护需求,既增加了维护点医院的经济效益又提升了社会效益。  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