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   6982篇
  免费   341篇
  国内免费   120篇
耳鼻咽喉   79篇
儿科学   47篇
妇产科学   23篇
基础医学   402篇
口腔科学   313篇
临床医学   330篇
内科学   143篇
皮肤病学   45篇
神经病学   39篇
特种医学   483篇
外科学   1052篇
综合类   855篇
预防医学   147篇
眼科学   28篇
药学   2116篇
  1篇
中国医学   964篇
肿瘤学   376篇
  2024年   56篇
  2023年   162篇
  2022年   251篇
  2021年   332篇
  2020年   287篇
  2019年   342篇
  2018年   346篇
  2017年   307篇
  2016年   294篇
  2015年   255篇
  2014年   451篇
  2013年   396篇
  2012年   433篇
  2011年   443篇
  2010年   337篇
  2009年   301篇
  2008年   316篇
  2007年   323篇
  2006年   285篇
  2005年   230篇
  2004年   203篇
  2003年   161篇
  2002年   118篇
  2001年   132篇
  2000年   98篇
  1999年   113篇
  1998年   54篇
  1997年   60篇
  1996年   61篇
  1995年   47篇
  1994年   38篇
  1993年   32篇
  1992年   26篇
  1991年   21篇
  1990年   14篇
  1989年   12篇
  1988年   14篇
  1987年   9篇
  1986年   12篇
  1985年   13篇
  1984年   11篇
  1983年   2篇
  1982年   14篇
  1981年   10篇
  1980年   5篇
  1979年   7篇
  1978年   5篇
  1976年   3篇
  1971年   1篇
排序方式: 共有7443条查询结果,搜索用时 31 毫秒
41.
带蒂联合皮瓣移植修复上肢广泛软组织缺损   总被引:2,自引:0,他引:2  
目的 探讨上肢广泛软组织缺损皮瓣修复方法的选择.方法 12例肘部、前臂及腕掌部高压电烧伤、热压伤及碾压伤患者,清创后4例应用背阔肌肌皮瓣与髂腰部皮瓣联合修复,将背阔肌肌皮瓣部分形成岛状,胸背血管蒂通过腋窝,上臂内侧皮下,髂腰部皮瓣部分以旋髂浅血管为蒂,皮瓣的蒂部形成皮管,位于腹股沟处,3周后再行断蒂;2例背阔肌肌皮瓣与侧胸皮瓣联合,将胸背动静脉游离出置于侧胸皮瓣内后形成皮管.蒂部位于侧胸上部;6例以巨大胸腹部联合皮瓣带蒂转移修复,以脐旁血管及肋间血管外侧皮支为轴,形成巨大皮瓣包绕前臂环形创面.结果 1例皮瓣远端局限坏死2 cm及皮瓣下感染,余全部成活,效果满意.结论 上肢创伤广泛软组织缺损,早期清创,应用带蒂联合皮瓣、肌皮瓣修复是一种简单、安全、可靠的方法.  相似文献   
42.
应用胫前肌瓣修复胫骨骨髓炎合并软组织缺损   总被引:1,自引:0,他引:1  
田勇 《中国骨伤》2006,19(10):622-622
自1999年1月-2005年3月,应用胫前肌瓣修复胫骨骨髓炎合并软组织缺损13例,同时辅以中药治疗,获得较满意的效果,现报告如下。1临床资料本组13例,男9例,女4例;年龄18~67岁,平均32岁。致伤原因:车祸伤6例,挤压伤4例,烧伤1例,坠落伤2例。胫骨上1/3段1例,中1/3段2例,下1/3段5例,中下2  相似文献   
43.
Plantar defects are a challenge for the plastic surgeon; from 1984–1995 59 operations were performed in 57 patients. The radial forearm flap and the latissimus dorsi (LD) flaps were mainly used depending on the amount of tissue loss. Local flaps such as dorsalis pedis and instep flaps were used for smaller defects. The radial forearm flap is ideal in terms of thickness and stability for the sole but limited in its size. The LD flap is a safe procedure especially for severe injuries and osteitis, but has the disadvantage of being bulky and debulking procedures are frequently performed. For nerve reconstruction deep sensibility seems to be sufficient in order to obtain stable postoperative results. In this report the different operative methods are evaluated. Since 1991, the patients were monitored with static and dynamic foot pressure measurements and gait analysis to assess the postoperative result and prevent pressure ulcers, scar irritation and hyperkeratosis. Preoperative investigations may contribute to an optimal schedule for planning and stabilization of the operative regimen.  相似文献   
44.
隐动脉筋膜蒂的交腿皮瓣修复小腿严重软组织缺损   总被引:7,自引:2,他引:5  
目的探讨一种小腿严重软组织缺损的修复方法。方法以健侧隐动脉为蒂的顺行或逆行交腿皮瓣修复患侧小腿软组织缺损。结果本组8例均有效地覆盖受区创面,随访三个月,皮瓣全部成活。结论该皮瓣不牺牲小腿的重要血管,质地与受区相似,方法简单易行,血运可靠,血管蒂长,是修复小腿严重软组织缺损的较好方法。  相似文献   
45.
Magnetic resonance imaging and pathologic findings in a 28-year-old patient with a giant deep benign fibrous histiocytoma in the popliteal fossa of the right knee are described. The MR imaging findings include a well-delineated oval mass with low signal intensity on T1-, and high signal intensity on T2-weighted, images, and marked peripheral contrast enhancement. To the best of our knowledge, this is the first report on the MR findings in this entity. Received 28 July 1997; Revision received 21 October 1997; Accepted 27 October 1997  相似文献   
46.
A microcapsule form of nitrofurantoin was prepared by a simple coacervation method with carboxymethylcellulose and aluminium sulfate. 33 factorial design was performed for three independent variables, namely, the particle size of the drug, the size of the microcapsules and the pH of the dissolution medium. The dissolution tests with the formulated microcapsules were carried out according to the United States Pharmacopeia XXII rotating basket method at pH 1.2, 5 and 7.5, which represent the pH of gastrointestinal fluids. Release data were examined kinetically and the ideal kinetic models were estimated and t 63.2 values obtained from RRSBW distribution were used in the factorial design experiment. The influence of the independent variables on the dissolution of nitrofurantoin microcapsules could be expressed as the pH of the dissolution medium > particle size of the microcapsule > particle size of nitrofurantoin. The other aim of this study was to evaluate microcapsule formulation in terms of the United States Pharmacopeia criteria with a minimum of experiments. Our findings suggest that dosage forms which comply with the pharmacopoeia criteria for dissolution can be prepared and selected by factorial design.  相似文献   
47.
The formation of 1.25-dihydroxycholecalciferol (1.25-(OH)2D3after single intravenous injections of 1-hydroxycholecalciferol(1-OHD3) was examined in four patients with chronic renal failureon regular haemodialysis. Following 1–3µg 1-OHD3administered at weekly intervals, 1.25-(OH)2D3 appeared in thecirculation within 1 h, and peak concentrations were reachedbetween 2 h and 5 h. By 8 h serum 1.25-(OH)2D3 concentrationshad started declining and by 44 h they had returned to baselineafter 1µg 1-OHD3 but they were still above basal after2 and 3 µg by an average of 30 pmol/l. One week afterinjections, concentrations were back to basal in all patientsstudied. The serum 1,25-(OH)2D3 dose response to injected la-OHDwas linear, indicating ample capacity of the liver 25-hydroxylaseto further hydroxylate 1-OHD. However, examination of the individualresponses revealed lower increments in serum 1.25-(OH)3 concentrationsin the patients with the highest basal serum 25-hydroxyvitaminD concen trations. Intravenous 1-OHD3 may be useful in the furtherstudy of the interactions between 1.25-(OH)23 calcium and PTHin chronic renal failure, as well as of the hepatic metabolismof vitamin D.  相似文献   
48.
Summary This study is aimed at the characterization of soft tissue tumours (STT) by means of cell surface molecules. To achieve this, normal mesenchymal tissues were extensively examined for expression of leucocyte differentiation (CD) antigens and HLA molecules. The panel of antigens finally examined in STT comprised CD10, CD13, CD24, CD34, CD36, CD56, CD57, HLA-A,B,C, 2-microglobulin, HLA-DR, -DP, and -DQ and the HLA-D-associated invariant chain (Ii). STT were determined by conventional histomorphological and immunohistochemical criteria. The immunohistological analysis was based on serial frozen sections, one of which was used to demonstrate CD53 antigen. This very broadly distributed leuco/histiocyte-restricted antigen allowed for the distinction between the background of interstitial stromal cells and the neoplastic population. In some STT, the expression pattern of the cell surface molecules corresponded to that in their non-neoplastic counterparts. The majority of STT, however, showed considerable changes in the cell surface immunophenotype compared to their cells of origin. These alterations consisted mainly in an aberrant induction/neoexpression and, to a much lesser extent, in an aberrant down-regulation/loss of cell surface antigens. Nevertheless, some immunophenotype configurations are described which, for the time being, can be considered to be useful supplements in the differential diagnosis of this complex class of tumours. The data also indicate considerable changes in cell surface antigen expression occurring in the course of neoplastic transformation of mesenchymal cells. Detailed analysis of alterations in the functional repertoire of neoplastic mesenchymal cells might provide new insights into the biology of STT, possibly leading to new concepts for therapeutic intervention.This study was supported by the Tumorzentrum Heidelberg/ Mannheim and by the Dr. Mildred-Scheel-Stiftung für Krebshilfe (W50/89/Mö2)  相似文献   
49.
A consecutive 10-year series of 278 soft tissue sarcomas was prospectively graded, using a system based on the number of mitoses and taking into account parameters such as cellularity, anaplasia, necrosis, and histogenetic type and subtype of tumour. Prognostic factors in relation to metastasis-free survival were studied by uni- and multivariate analysis. Fifty-seven (20.5 per cent) were low-grade tumours, 43 (15.5 per cent) were intermediate, and 178 (64 per cent) were high grade. High-grade tumours were divided into two groups; 80 (29 per cent) grade 3A (= 5-20 mitoses per 10 high power fields (HPF)) and 78 grade 3B (28 per cent) (= more than 20 mitoses/10 HPF); 10 HPF corresponds to 2.5 mm2. Twenty (7.2 per cent) high-grade tumours could not be further subdivided. Grading was found to be the prognostic factor associated with the strongest predictive value. Five-year survival in low-grade and intermediate tumours (95 and 86 percent, respectively) differed significantly (P less than 0.0001) from high grade (50 per cent) and (p = 0.0018) between grade 3A (64 per cent) and grade 3B (41 per cent). Other prognostic indicators of importance in high-grade tumours were age, local recurrence at presentation (primary operation outside the Centre), and localization (superficial vs. deep).  相似文献   
50.
A testing device has been developed which simultaneously measures,in vitro, the anisotropic dynamic viscoelastic moduli of bidimensional biological membranes such as the vascular wall, mesentery or skin. These measurements can be carried out as a function of the frequencies (0·5 Hz to 15 Hz) and the initial bidimensional strains (in a range of extension ratios λx and λy varying from 1·005 to 2·3 for a 3×3 cm specimen). The amplitude of the periodical deformations in both directions amounts to 0·25 percent of the undeformed dimensions.  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