全文获取类型
收费全文 | 4523篇 |
免费 | 83篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 40篇 |
妇产科学 | 1680篇 |
基础医学 | 196篇 |
口腔科学 | 23篇 |
临床医学 | 165篇 |
内科学 | 346篇 |
皮肤病学 | 673篇 |
神经病学 | 451篇 |
特种医学 | 188篇 |
外科学 | 384篇 |
综合类 | 23篇 |
预防医学 | 87篇 |
眼科学 | 7篇 |
药学 | 91篇 |
2篇 | |
中国医学 | 1篇 |
肿瘤学 | 175篇 |
出版年
2014年 | 42篇 |
2013年 | 44篇 |
2012年 | 68篇 |
2011年 | 72篇 |
2010年 | 41篇 |
2009年 | 53篇 |
2008年 | 70篇 |
2007年 | 79篇 |
2006年 | 70篇 |
2005年 | 61篇 |
2004年 | 52篇 |
2003年 | 60篇 |
2002年 | 51篇 |
2001年 | 52篇 |
2000年 | 52篇 |
1999年 | 46篇 |
1997年 | 40篇 |
1989年 | 44篇 |
1987年 | 59篇 |
1985年 | 51篇 |
1975年 | 71篇 |
1973年 | 64篇 |
1971年 | 68篇 |
1969年 | 51篇 |
1967年 | 68篇 |
1965年 | 54篇 |
1964年 | 55篇 |
1963年 | 54篇 |
1961年 | 54篇 |
1959年 | 63篇 |
1957年 | 64篇 |
1955年 | 109篇 |
1954年 | 81篇 |
1942年 | 90篇 |
1938年 | 80篇 |
1936年 | 63篇 |
1935年 | 45篇 |
1933年 | 71篇 |
1931年 | 112篇 |
1930年 | 100篇 |
1929年 | 150篇 |
1928年 | 155篇 |
1927年 | 119篇 |
1926年 | 189篇 |
1925年 | 151篇 |
1924年 | 128篇 |
1923年 | 125篇 |
1922年 | 209篇 |
1912年 | 48篇 |
1889年 | 40篇 |
排序方式: 共有4628条查询结果,搜索用时 46 毫秒
61.
Hartwig CH Esenwein SA Pfund A Küsswetter Dagger W Herr G 《Zeitschrift für Orthop?die und ihre Grenzgebiete》2003,141(6):705-711
AIM: Aim of this study was to determine whether coating of titanium implants of various surfaces with BMP-3 would improve the osseous integration of the implants into the orthotopic bony implant bed. METHOD: In this experimental study 190 micro g per implant of highly purified bone morphogenetic protein 3 (BMP-3) precipitate isolated from porcine bone were available for the coating of each of 24 cylindrical test implants (12 with hydroxyapatite and 12 with plasmapore surface). The remaining 24 test implants with the same surface makeup served as negative controls. Implantation sites were randomly assigned for the 4 versions of implants available and all implants were embedded into the medial or lateral femoral condyle of both legs of 12 German shepherds. The drilling holes were performed in such a matter that after embedding the cylindrical devices a gap of 1 mm surrounding the implants remained. A biomechanical testing and histological evaluation was performed on the explants 42 days after surgery. RESULTS: In biomechanical testing forces necessary to extract the implants from the explanted bones in BMP-3 coated devices were up to 70% higher compared to the ones in the non-coated reference groups. Quantitative histomorphometric examination showed in BMP-3-coated implants an increasing formation of new bone close to their own surface (gap-healing) which was higher than in the corresponding non-coated controls (hydroxyapatite + BMP-3 32.1%, hydroxyapatite controls 20.3%, plasmapore + BMP-3 30.2%, plasmapore controls 13.1%). The extent of direct bone implant contact as percentiles of the corresponding implants perimeter (ongrowth) was also significantly higher in the BMP-3-coated implants compared to the non-coated controls (hydroxyapatite + BMP-3 37.7%, hydroxyapatite controls 22.4%, plasmapore + BMP-3 15.3%, plasmapore controls 6.4%). CONCLUSION: In this study it was proven the first time that implants of various surface textures as used in endoprosthetics are able to be coated by the osteoinductive growth factor BMP-3. In that way metallic implants can achieve osteogenic properties which have positive effects in osseointegration. 相似文献
62.
Multiphasic examinations of 153 gastric abnormalities observed radiologically and endoscopically were reviewed to determine the efficacy of four radiologic techniques and of several common combinations of these techniques for examining the stomach. There were 68 gastric ulcers, 12 ulcer scars, 44 cases of gastritis including 27 with erosions, 24 benign neoplasms, and five malignancies. Double-contrast, compression, mucosal relief, and full-column techniques detected 82%, 65%, 62%, and 51%, respectively, of all lesions diagnosed with the complete multiphasic examinations. Results indicate that the greater the number of techniques employed, the more accurate the examination, with biphasic and multiphasic examinations detecting 9%-18% more lesions overall than simple single- or double-contrast studies. 相似文献
63.
Eleven radiologists appointed by the major radiological societies participated for the past 5 years in the development of the Health Policy Agenda for the American People. The Agenda is an action plan to address a wide variety of serious problems in medicine. The first phase involved establishment of 159 principles, broad value statements that were the foundation of the project. Phase 2 involved the development of policy proposals on 38 urgent issues for action in medical science; education; health resources; delivery mechanisms; evaluation, assessment, and control; and payment for services. These proposals are summarized in this report. The activities and recommendations of representatives for the field of radiology are described. The Agenda has been released, and an implementation phase has begun. It will likely be of great importance to the practice of radiology over the next decade. Important issues can be addressed by acting with the coalitions that are being formed from among the more than 150 participating organizations. 相似文献
64.
Meniscal tears of the knee: accuracy of MR imaging 总被引:39,自引:0,他引:39
Before surgery, 277 menisci in 144 knees were examined with magnetic resonance (MR) imaging. They were then examined directly with arthroscopy or arthrotomy. Menisci were graded on a scale of 1-3 according to the character of the intrameniscal MR imaging signal. At surgery, 137 of 154 (89%) menisci exhibiting only grade 1 or grade 2 signal were found to be normal. One hundred sixteen of 123 (94%) menisci exhibiting intrameniscal signal communicating with a meniscal articular surface (grade 3 signal) had tears. If only a grade 3 signal is considered consistent with meniscal tears, then MR findings and surgical findings agreed in 91.3% of menisci. MR imaging can separate surgically significant from nonsignificant meniscal lesions and is useful in the noninvasive preoperative screening of suspected meniscal tears. 相似文献
65.
Surface shield: device to reduce personnel radiation exposure 总被引:2,自引:0,他引:2
Young AT; Morin RL; Hunter DW; Nelson KL; Cardella JF; Castaneda-Zuniga WR; Amplatz K 《Radiology》1986,159(3):801-803
A simple device is described that can reduce personnel exposure from scatter radiation by up to 75%. The device consists of an oblong piece of shielding (0.75-mm lead equivalent) that is taped to the side of the patient during percutaneous renal stone removal and other interventional procedures. Contrary to other shields and barriers, this does not interfere with access to the patient. Scatter exposure data from phantom studies are presented and the rationale for surface shielding discussed. 相似文献
66.
A new technique has been designed to improve myelography examinations of the entire lumbar spinal canal in patients with severe spinal stenosis using a single needle puncture. When a high-grade obstruction to the caudal flow of contrast material is encountered, the patient is placed in a flexed sitting position for 1 minute. This technique was performed in eight patients with severe lumbar spinal stenosis. It successfully helped depict the lower lumbosacral canal below an apparently complete block in four patients and resulted in improved visualization of the lower sac in four patients with partial block. 相似文献
67.
Urine-compatible polymer for long-term ureteral stenting 总被引:1,自引:0,他引:1
Internal double-J ureteral stents were designed from a urine-compatible polymer (C-Flex), and 35 stents were placed in patients. The overall patency rate for the stents was 80%, with most stent failures occurring before 2 months; the follow-up period ranged from 2 to 16 months, with a mean follow-up for all stents of 5.0 months. Stents were considered patent at last follow-up only if they had been in place for at least 2 months. No migration or fracture of the stents occurred. Physical properties of urine-exposed stents were compared with those of virgin tubing and tubing exposed for 1 year to shelf conditions. Stent patency was optimized by increasing urine flow by increasing the patient's voluntary oral intake, administering prophylactic oral antibiotics, and avoiding placement of stents into grossly bloody or infected collecting systems. 相似文献
68.
OBJECTIVE: To determine whether pathology on a re-staging transurethral resection (TUR) predicts the early progression of superficial bladder cancer. PATIENTS AND METHODS: In all, 710 patients presenting with multiple superficial bladder cancers were evaluated by re-staging TUR and followed for 5 years. Tumours were classified by stage as confined to mucosa (Ta) or invading submucosa (T1), and by grade (low- or high-grade). Pathology on re-staging TUR was correlated with the endpoints of tumour recurrence and stage progression. RESULTS: Of the 710 patients, 490 (69%) had a recurrence and 149 (21%) progressed over 5 years. Eighty patients had high-grade invasive (T1G3) cancer on re-staging TUR and 61 (76%) progressed to muscle invasion (median time to progression 15 months), compared with 88 of 630 (14%) who had no evidence of tumour (T0) or other than T1 tumours detected on re-staging TUR. CONCLUSION: A re-staging TUR identifies patients with superficial bladder cancer who are at high risk of early tumour progression. 相似文献
69.
Context
The optimal treatment strategy for muscle-invasive bladder cancer remains controversial.Objective
To determine optimal combination of chemotherapy and surgery aimed at preserving survival of patients with locally advanced bladder cancer.Evidence acquisition
We performed a critical review of the published abstract and presentation literature on combined modality therapy for muscle-invasive bladder cancer. We emphasized articles of the highest scientific level, combining radical cystectomy and perioperative chemotherapy with curative intent to affect overall and disease-specific survival.Evidence synthesis
Locally invasive, regional, and occult micrometastases at the time of radical cystectomy lead to both distant and local failure, causing bladder cancer deaths. Neoadjuvant and adjuvant chemotherapy regimens have been evaluated, as well as the quality of cystectomy and pelvic lymph node dissection.Conclusions
Prospective, randomized clinical trials argue strongly for neoadjuvant cisplatin-based chemotherapy followed by high-quality cystectomy performed by an experienced surgeon operating in a high-volume center. Adjuvant chemotherapy after surgery is also effective when therapeutic doses can be given in a timely fashion. Both contribute to improved overall survival; however, many patients receive only one or none of these options, and the barriers to receiving optimal, combined, systemic therapy and surgery remain to be defined. An aging, comorbid, and often unfit population increasingly affected by bladder cancer poses significant challenges in management of individual patients. 相似文献70.
Robert C. Griggs MD Barbara E. Herr MS Allen Reha PhD Gary Elfring Leone Atkinson MD Valerie Cwik MD Elaine Mccoll PhD Rabi Tawil MD Shree Pandya RPT MS Michael P. McDermott PhD Kate Bushby MD 《Muscle & nerve》2013,48(1):27-31
Introduction: In 2004, a Cochrane Review and AAN practice parameter concluded that prednisone 0.75 mg/kg/day is of short‐term efficacy in Duchenne muscular dystrophy (DMD). Subsequent efforts to standardize care for DMD indicated wide variation in corticosteroid use. Methods: We surveyed physicians who follow patients with DMD, including: (1) clinics in the TREAT‐NMD (Translational Research in Europe—Assessment and Treatment of Neuromuscular Diseases) network (predominantly Europe) and (2) U.S. MDA clinic directors. We also documented the co‐administered corticosteroids in a trial of a putative treatment (ataluren) for DMD. Results: Of 105 Treat‐NMD clinicians, corticosteroids were not used in 10 clinics, and 29 different regimens were used—the most frequent 0.75 mg/kg/day prednisone (61 centers); 10 days on/10 days off (36 centers); 0.9 mg/kg/day deflazacort (32 centers); and 5 mg/kg/day on weekends (10 centers). Similar diversity was identified in MDA clinics and in the ataluren trial. Conclusions: Variability in corticosteroid use suggests uncertainty about risks/benefits of corticosteroid regimens for DMD. Muscle Nerve, 2013 相似文献