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   74671篇
  免费   5339篇
  国内免费   1599篇
耳鼻咽喉   3089篇
儿科学   872篇
妇产科学   1503篇
基础医学   1822篇
口腔科学   3132篇
临床医学   6919篇
内科学   6989篇
皮肤病学   695篇
神经病学   2528篇
特种医学   1218篇
外国民族医学   20篇
外科学   25973篇
综合类   10205篇
现状与发展   6篇
一般理论   2篇
预防医学   2638篇
眼科学   4541篇
药学   3010篇
  164篇
中国医学   832篇
肿瘤学   5451篇
  2024年   83篇
  2023年   1999篇
  2022年   2376篇
  2021年   3830篇
  2020年   4107篇
  2019年   3504篇
  2018年   3354篇
  2017年   2898篇
  2016年   2891篇
  2015年   2937篇
  2014年   5789篇
  2013年   5401篇
  2012年   4345篇
  2011年   4564篇
  2010年   3615篇
  2009年   3432篇
  2008年   3285篇
  2007年   3276篇
  2006年   2858篇
  2005年   2507篇
  2004年   2173篇
  2003年   1747篇
  2002年   1380篇
  2001年   1313篇
  2000年   1129篇
  1999年   1024篇
  1998年   817篇
  1997年   754篇
  1996年   561篇
  1995年   489篇
  1994年   432篇
  1993年   349篇
  1992年   295篇
  1991年   293篇
  1990年   197篇
  1989年   193篇
  1988年   193篇
  1987年   194篇
  1986年   153篇
  1985年   169篇
  1984年   158篇
  1983年   101篇
  1982年   105篇
  1981年   95篇
  1980年   76篇
  1979年   44篇
  1978年   33篇
  1977年   32篇
  1976年   24篇
  1975年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
目的 系统评价神经内镜与显微镜下经鼻蝶入路手术切除无功能性垂体腺瘤的疗效和安全性。方法 计算机检索PubMed 、Embase、Cochrane Center、中国生物医学文献数据库、维普中文科技期刊全文数据库、万方数据库、中国知网等中英文数据库有关神经内镜、显微镜下经鼻蝶入路无功能性垂体腺瘤切除术的文献,时限为2018年7月之前。指标包括肿瘤切除率、脑脊液渗漏发生率和视力恢复率。结果 共纳入19篇文献,2 383例。Meta分析结果:神经内镜手术全切除率比显微镜手术要高(75% vs 62%,P<0.001),神经内镜组视力恢复率也高于显微镜组(82% vs 59%,P<0.001)。两组脑脊液漏发生率无统计学差异(4%vs 6%,P=0.078)。结论 与显微镜下手术相比,神经内镜手术切除无功能性垂体腺瘤的疗效更好。  相似文献   
93.
《Journal of vascular surgery》2019,69(5):1559-1565
ObjectiveAdvancement in academic medicine is multifactorial. Our objectives were to characterize academic appointments in vascular surgery and to investigate what factors, particularly publications, influenced academic appointment.MethodsAcademic vascular surgeons at Accreditation Council for Graduate Medical Education vascular training programs or at primary sites of U.S. allopathic medical schools were included. Those with qualified titles, such as “adjunct” or a “clinical” prefix, were excluded. Sex, education, region, board certification, and affiliation details were recorded. Web of Science was queried for publication details and h-index. The h-index is a “personal impact factor” defined as “x” number of publications cited at least “x” number of times. After surgeons' information was deidentified, univariate and multivariable analyses were completed for academic appointment and appointment as division chief.ResultsThere were 642 vascular surgeons who met criteria: 297 (46.3%) assistant professors, 150 (23.4%) associate professors, and 195 (30.4%) professors. There were 96 (15%) division chiefs and 10 (1.6%) chairs of surgery, and 83.2% were male. Surgeons worked in the Northeast (33.5%), Southern (32.6%), Central (20.1%), and Western (13.9%) United States. The mean (±standard deviation) number of publications was 13.7 ± 15.4 for assistant professors, 33.9 ± 28.8 for associate professors, and 86.8 ± 63.6 for professors (P < .001). Mean number of first or last author publications was 5.3 ± 6.4 for assistant professors, 12.2 ± 12.7 for associate professors, and 38.7 ± 35.3 for professors (P < .001). Mean h-index was 5.9 ± 5.4 for assistant professors, 12 ± 7.7 for associate professors, and 24.9 ± 12.6 for professors (P < .001). In multivariable analysis, vascular surgery board certification (adjusted odds ratio [OR], 6.08; 95% confidence interval [CI], 1.15-32.2; P = .03), academic appointment at a public medical school (OR, 1.99; 95% CI, 1.18-3.37; P = .01), years since medical school graduation (OR, 1.13; 95% CI, 1.09-1.18; P < .001, per year), and number of publications (OR, 1.05; 95% CI, 1.03-1.06; P < .001, per publication) were independently associated with associate professor. Factors independently associated with professor were years since medical school graduation (OR, 1.18; 95% CI, 1.12-1.24; P < .001, per year) and number of first or last author publications (OR, 1.05; 95% CI, 1.02-1.09; P = .003, per publication). Appointment as division chief was independently associated with h-index (OR, 1.04; 95% CI, 1.01-1.08; P = .016, per point).ConclusionsTotal number of publications was independently associated with associate professor, with number of first or last author publications particularly important for professor. The h-index was not independently associated with academic appointment, but it was for appointment as division chief. This study provides relevant data for promotional guidance in academic vascular surgery.  相似文献   
94.
Background and objectiveExcision of cutaneous scalp tumors results in surgical defects that are difficult to repair because of poor distensibility in this area of the body. The main aim of this study was to develop a structured algorithm to help choose the best technique for reconstructing scalp defects.Material and methodsRetrospective study of patients who required surgical reconstruction following excision of a cutaneous scalp tumor. We excluded patients with defects that could be closed by simple direct suture and defects for which it was initially decided to use a skin graft or healing by secondary intention. The defects were classified into 5 groups according to the minimum distance between edges. The different reconstruction techniques used were evaluated in each group. The outcomes analyzed were complete defect closure, intraoperative and postoperative complications, and final aesthetic result.ResultsWe included 119 patients (102 men and 17 women) with a mean age of 71 years (range, 32–93 years). Mean follow-up was 42 months (range, 6–120 months). Sixty-eight patients had a moderate-sized defect with a distance between edges of 1 to 4 cm. Reconstructions started with relaxation incisions in 43 defects and resulted in the successful closure of 22 of them. Defects with a distance of 1 to 2 cm required a single relaxation incision. Two incisions were required for defects with a distance of 2 to 3 cm, while 3 incisions were required for those with a distance of 3 to 4 cm. In the 21 cases in which relaxation incisions were insufficient to close the defect, the incisions were extended to mobilize the flap to achieve closure. Relaxation incisions alone were insufficient for closing defects with a distance greater than 4 cm.ConclusionsThe 1-2-3 rule can help in choosing the best reconstruction technique for moderate-sized defects based on the principle that 1, 2, or 3 initial relaxation incisions are needed depending on the minimum distance between edges (1-2 cm, 2-3 cm, or 3-4 cm). In all cases, incision extension to mobilize the corresponding flaps remains an option.  相似文献   
95.
Depigmented patches in vitiligo, a common dermatosis, cause a great psychological distress to the patients. Hence, apart from halting the disease process, the strategies to impart normal skin colour to these white patches carry an important role in the management of vitiligo. Surgical procedures are often required for stable vitiligo lesions not responding to medical therapies. It involves “shuffling” of melanocytes from the pigmented skin to the depigmented areas. During the last fifty years, the vitiligo surgery has evolved from tissue transplantation via cellular transplantation to reach a stage where the use of stem cells or immunomodulatory cells is contemplating. We would like to depict this wonderful journey of vitiligo surgery through this viewpoint.  相似文献   
96.
97.
The aim of this study was to compare the alterations in three regions of the airway—nasopharynx, oropharynx, and hypopharynx—in relation to the area of the midsagittal plane, volume, and minimal axial area after maxillomandibular advancement (MMA) surgery. Thirty patients who had undergone MMA surgery were evaluated at four time points: preoperative (T0), immediately postoperative (T1), 1 year postoperative (T2), and ≥5 years postoperative (T3). All measurements were performed using computed tomography, analyzed in Dolphin Imaging 11.0 Premium 3D software. The area in the midsagittal plane presented a mean increase of 22.0% between T0 and T3 (P < 0.001), with the highest increase in the oropharynx (24.1%, P < 0.001). The total volumetric increase at T3 was 16.7% (P < 0.001), with the highest increase in the nasopharynx (15.7%; P < 0.001). The lowest minimal axial area was found for the oropharynx at all time points, and the highest increase in minimal axial area was found for the nasopharynx (114.9%; P < 0.001). MMA surgery showed the highest increase in upper posterior airway between T0 and T1, and this was followed by a progressive reduction until T3, but with a statistically significant increase at T3 compared with T0 in all cases.  相似文献   
98.
99.
Three-dimensional surgical planning is used widely in orthognathic surgery. Although numerous computer programs exist, the accuracy of soft tissue prediction remains uncertain. The purpose of this study was to compare the prediction accuracy of Dolphin, ProPlan CMF, and a probabilistic finite element method (PFEM). Seven patients (mean age 18 years; five female) who had undergone Le Fort I osteotomy with preoperative and 1-year postoperative cone beam computed tomography (CBCT) were included. The three programs were used for soft tissue prediction using planned and postoperative maxillary position, and these were compared to postoperative CBCT. Accurate predictions were obtained with each program, indicated by root mean square distances: RMSDolphin = 1.8 ± 0.8 mm, RMSProPlan = 1.2 ± 0.4 mm, and RMSPFEM = 1.3 ± 0.4 mm. Dolphin utilizes a landmark-based algorithm allowing for patient-specific bone-to-soft tissue ratios, which works well for cephalometric radiographs but has limited three-dimensional accuracy, whilst ProPlan and PFEM provide better three-dimensional predictions with continuous displacements. Patient or population-specific material properties can be defined in PFEM, while no soft tissue parameters are adjustable in ProPlan. Important clinical considerations are the topological differences between predictions due to the three algorithms, the non-negligible influence of the mismatch between planned and postoperative maxillary position, and the learning curve associated with sophisticated programs like PFEM.  相似文献   
100.
BackgroundHaving had a previous experience of 4 open F2 osteotomies to correct interphalangeal hallux valgus, the aim of this study was to test the efficacy of a percutaneous approach for this correction.Methods3 open and 12 percutaneous F2 osteotomies in 15 cadaver feet were performed. Interphalangeal (IPH), F2 asymmetry (AF2) and joint deviation (JD) angles were measured on radiographs. The operated great toes were anatomically analyzed looking for possible lesions to surrounding tissues.ResultsMean IPH decreased from 10.7° to 2.9°, AF2 from 7.8° to 1°, and JD from 1.4° to 0.5°. Damage to the hallux extensor tendon was detected in 1 foot and a nail bed lesion was detected in 1 case, both operated percutaneously.ConclusionsF2 Valgus deformity can be corrected using open or percutaneous osteotomy. The authors consider the open correction worthwhile because percutaneous techniques may damage surrounding tissues and the incision length difference is minor.Level of clinical evidence: 3.  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