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   182158篇
  免费   1456篇
  国内免费   33篇
耳鼻咽喉   1202篇
儿科学   6784篇
妇产科学   3206篇
基础医学   17486篇
口腔科学   1889篇
临床医学   13128篇
内科学   32119篇
皮肤病学   839篇
神经病学   17179篇
特种医学   9043篇
外科学   29446篇
综合类   2353篇
一般理论   9篇
预防医学   18848篇
眼科学   2823篇
药学   9917篇
中国医学   648篇
肿瘤学   16728篇
  2023年   130篇
  2022年   214篇
  2021年   407篇
  2020年   242篇
  2019年   326篇
  2018年   22209篇
  2017年   17577篇
  2016年   19723篇
  2015年   1203篇
  2014年   1204篇
  2013年   1219篇
  2012年   7659篇
  2011年   21653篇
  2010年   19125篇
  2009年   11782篇
  2008年   19870篇
  2007年   22091篇
  2006年   884篇
  2005年   2457篇
  2004年   3565篇
  2003年   4497篇
  2002年   2642篇
  2001年   296篇
  2000年   426篇
  1999年   211篇
  1998年   214篇
  1997年   211篇
  1996年   98篇
  1995年   109篇
  1994年   104篇
  1993年   71篇
  1992年   61篇
  1991年   98篇
  1990年   148篇
  1989年   92篇
  1988年   68篇
  1987年   50篇
  1986年   43篇
  1985年   44篇
  1984年   28篇
  1983年   27篇
  1982年   30篇
  1980年   44篇
  1969年   23篇
  1938年   60篇
  1937年   25篇
  1935年   22篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Obtaining symmetric and balanced gaps under equilateral loads is a common goal in posterior cruciate ligament (PCL)-retaining and -sacrificing TKAs. Owing to limitations in existing surgical tensors, however, tensing knee ligaments with standardized and symmetric loads has been possible only with the patella subluxated or everted. We therefore determined the influences of (1) patellar eversion versus complete reduction, (2) PCL resection, and (3) load magnitude on gap symmetry and balance in the anterior cruciate ligament (ACL)-deficient knee. We used a novel computer-controlled tensioner to measure gaps in 10 cadavers with an applied force of 50 N, 75 N, and 100 N per side. Gap data were acquired at 0o, 30o, 60o, 90o, and 120o flexion with the patella reduced and everted and with the PCL intact and resected. Everting the patella tightened the medial and lateral flexion gaps between 90o and 120o by 0.7 mm to 2.7 mm. PCL resection increased gaps from 30° to 120° by 1 mm to 3 mm. Increasing the force from 50 N to 100 N increased the mean gap by 0.5 mm. Everting the patella and resecting the PCL influenced gap balance and symmetry. Surgeons should be aware of how these conditions affect gaps during assessment and balancing. Richard Laskin—Deceased. One of the authors (CP) is employed by Praxim Inc, Walpole, MA. Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.  相似文献   
992.
Chemoradiotherapy has become a popular definitive therapy among many patients and oncologists for potentially resectable esophageal carcinoma. Although the complete response rates are high and short-term survival is favorable after chemoradiotherapy, persistent or recurrent locoregional disease is quite frequent. Salvage surgery is the sole curative intent treatment option for this course. As experience with definitive chemoradiotherapy grows, the number of salvage surgeries may increase. Selected articles about salvage esophagectomy after definitive chemoradiotherapy for esophageal carcinoma are reviewed. The number of salvage surgeries was significantly lower than the number of expected candidates. To identify candidates for salvage surgery, patients undergoing definitive chemoradiotherapy should be followed up carefully. Salvage esophagectomy is difficult when dissecting fibrotic masses from irradiated tissues. Patients who underwent salvage esophagectomy had increased morbidity and mortality. Pulmonary complications such as pneumonia and acute respiratory distress syndrome were common. The anastomotic leak rate was significantly increased because of the effects of the radiation administered to the tissues used as conduits. The most significant factor associated with long-term survival appeared to be complete resection. However, precise evaluation of resectability before operation was difficult. Nevertheless, increased morbidity and mortality will be acceptable in exchange for potential long-term survival after salvage esophagectomy. Such treatment should be considered for carefully selected patients at specialized centers. This review was submitted at the invitation of the editorial committee.  相似文献   
993.
An 89-year-old woman with dyspnea and disturbed consciousness due to hypoventilation was admitted to our hospital. Chest radiography showed no abnormal shadow, but she was intubated for deteriorated hypoventilation. Bronchoscopy demonstrated obstruction of the left main bronchus at the carina. Computed tomography (CT) showed neither a mass lesion in the mediastinum nor an aortic aneurysm, but compression of the airway by the ascending aorta was observed. It was thought that the patient’s thin thoracic cage was unable to support the weight of the ascending aorta, which consequently compressed the left main bronchus. After inserting stents into both main bronchi, the patient’s consciousness improved, and respirator support was withdrawn. In aged, bedridden, thin patients with hypopnea or recurrent airway infection, CT and bronchoscopy should be performed to investigate airway patency.  相似文献   
994.
We report a rare case of biphasic pulmonary blastoma (BPB) with rapid progression in a 75-year-old man. Computed tomography (CT) of the chest revealed a well-defined tumor shadow measuring 8 × 6 cm in the right upper lobe. CT-guided lung biopsy revealed malignant cells with sarcomatous elements. Right upper lobectomy and systemic lymph node dissection with chest wall resection were performed. Histopathologically, the tumor was composed of immature embryoniclike mesenchymal and epithelial components that resembled embryonic lung tissue. The final diagnosis was BPB classified as pathological stage IIB (T3N0M0). Two months later, the tumor recurred in the right supraclavicular lymph nodes. The patient died of respiratory failure due to tumor progression 7 months after surgery.  相似文献   
995.
Descending necrotizing mediastinitis (DNM) is a rare but severe disease with a high mortality rate. We report a case of a 77-year-old woman with DNM who was treated using video-thoracoscopic drainage and a Blake drain. She was admitted to our hospital with a 3-day history of a sore throat. Computed tomography (CT) revealed a peritonsillar abscess descending into the anterior and posterior mediastinum below the carina. She was diagnosed with DNM, and emergency surgery was performed. The mediastinal abscess was drained via video-thoracoscopy, and a 24F Blake drain was inserted into the mediastinum. Following mediastinal drainage, cervical drainage was performed for treatment of the retropharyngeal abscess. The outcome of videothoracoscopic mediastinal drainage was satisfactory, and no further invasive treatment was required. We believe that video-thoracoscopic mediastinal drainage is an effective, minimally invasive treatment for DNM with subcarinal spread. Blake drains are useful for mediastinal drainage.  相似文献   
996.
The problem of early mechanical stability of cemented and cementless keels of the tibial component in total knee arthroplasty (TKA) is controversial. The purpose of this study was to assess clinical and radiographic outcomes of a cohort of 51 TKAs using a cemented platform with cementless keel fixation. At a mean follow-up of 10.4 years (range, 7 to 14 years), the mean Knee Society Score (KSS) was 93 points (range, 59 to 100 points), and the mean functional score was 73 points (range, 0 to 100 points). Only one patient demonstrated progressive tibial radiolucencies at 13.1 years follow-up, which resolved with a revision with an exchange of components. The results of this study suggest that a proximally cemented tibial tray with a press-fit keel TKA provides excellent mean 10-year outcomes.
Résumé  Le problème de la stabilité précoce immédiate de la quille du composant tibial d’une prothèse totale du genou est sujet à controverse. Le propos de cette étude est d’étudier le devenir clinique et radiographique d’une cohorte de 51 prothèses totales du genou, avec un plateau cimenté sans fixation cimentée de la quille. Après un suivi moyen de 10,4 ans (de 7 à 14 ans), le score de la Knee Society a été de 93 points (59 à 100 points) et le score fonctionnel moyen de 73 points (de 0 à 100 points). Seulement un patient a présenté un liseré tibial progressif 13,1 ans après l’intervention avec une nécessité de révision et de changement prothétique. Le résultat de cette étude permet de penser qu’un plateau tibial cimenté avec une quille en press-fit permet d’obtenir de bons résultats avec au moins 10 ans de recul.


Two of the authors (FRK and MAM) received financial support from Stryker Orthopaedics, Mahwah, New Jersey.
Each author certifies that his or her institution has approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.
The authors FRK and MAM contributed equally to this work.  相似文献   
997.
In this study, we performed a mechanical analysis of the effect of fibroblast growth factor-2 (FGF-2) on autologous osteochondral transplantation in a rabbit model. A full-thickness cartilage defect (diameter: 5 mm; depth: 5 mm) made in the right femoral condyle was treated with osteochondral transplantation using an osteochondral plug (diameter: 6 mm; depth: 5 mm) taken from the left femoral condyle. The animals were divided into three groups: Group I, the defect was filled with 0.1 ml of gelatin hydrogel containing 1 microg of FGF-2; Group II, the defect was filled with 0.1 ml of gelatin hydrogel only; Group III, the defect was left untreated. Thereafter, osteochondral plugs were transplanted and the transplanted osteochondral grafts were evaluated mechanically and histologically at postoperative weeks 1, 3, 8 and 12. The structural property of the osteochondral graft was significantly greater in Group I than in Groups II and III at postoperative week 3. Histological analysis at 3 weeks revealed a tendency towards increased subchondral bone trabeculae in Group I compared with the other groups. Autologous osteochondral grafts transplanted with gelatin hydrogel containing FGF-2 acquired adequate stiffness at an early postoperative phase.  相似文献   
998.
Background and aims  Bleeding from the hepatic vein is closely related to central venous pressure (CVP). To evaluate the effect of low central venous pressure during a hepatectomy, the infrahepatic inferior vena cava (IVC) was half clamped. Patients and methods  Between 2006 and 2007, 20 patients undergoing major hepatectomy with the IVC half clamping (half-clamping group) were compared with 58 patients undergoing hepatectomy without IVC half clamping between 2003 and 2005 (control group). The types of liver resection, amount of blood loss during the hepatectomy, volume of blood transfusion, length of hospital stay, and complications were compared between the two groups. Results  In the half-clamping group, blood loss was decreased in comparison to the control group (p = 0.041) and the suprahepatic CVP was low (2.4 ± 1.8 mmHg; p = 0.0002). The diameter at the root of the right hepatic vein was reduced in comparison to before clamping (5.8 ± 1.6 mm; p < 0.001). There were no complications of half clamping on any hemodynamic and blood electrolytic parameters. Conclusion  Using the half clamping technique of the IVC, intra-operative CVP was maintained below 3 mmHg without any side effects, and the low CVP significantly reduced the bleeding from hepatic veins during a major hepatectomy.  相似文献   
999.
Purpose  The exact relationship between larger caseload volume and lower morbidity following esophagectomy has not been established. This study investigates the effect of surgical volumes on reducing postoperative complications and length of stay after esophagectomy. Methods  Patient and hospital data were collected electronically via a web-based questionnaire sent to surgeons in the Japan Surgical Society. Data were based on 642 patients treated with esophagectomy at 183 hospitals between November 1, 2006 and February 28, 2007. Multivariate analysis revealed that postoperative morbidity and length of stay regressed against hospital and surgeon volumes, patient characteristics, and details of the procedures. Results  In a logistic regression model, esophagectomies by surgeons performing a high volume of operations (>100 cases; “high case-volume surgeons”) were followed by a significantly lower rate of postoperative complications (odds ratio [OR], 0.49; 95% confidence interval (CI), 0.24–0.98, P = 0.04). In a proportional hazard model, high-volume surgeons reduced the length of stay significantly: the hazard ratio for medium casevolume surgeons (50–99 cases) was 1.53 [95% CI, 1.14–2.06, P = 0.00], whereas that for the highest case-volume surgeons was 1.34 [95% CI, 1.00–1.79, P = 0.05] vs the lowest case-volume surgeons. Neither postoperative complications nor length of stay were significantly associated with hospital volume. Conclusion  These findings indicate that morbidity after esophagectomy is more dependent on individual surgeon-specific skill than on hospital-based factors.  相似文献   
1000.
This biographical sketch of Marshall R. Urist corresponds to the historic texts, The Classic: Bone Morphogenetic Protein, available at DOI  10.1007/s11999-009-1068-3; The Classic: A Morphogenetic Matrix for Differentiation of Cartilage in Tissue Culture, available at DOI  10.1007/s11999-009-1069-2; and The Classic: A Morphogenetic Matrix for Differentiation of Bone Tissue, available at DOI  10.1007/s11999-009-1070-9.  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