全文获取类型
收费全文 | 423079篇 |
免费 | 16402篇 |
国内免费 | 641篇 |
专业分类
耳鼻咽喉 | 4045篇 |
儿科学 | 14872篇 |
妇产科学 | 8578篇 |
基础医学 | 51232篇 |
口腔科学 | 10360篇 |
临床医学 | 34021篇 |
内科学 | 85868篇 |
皮肤病学 | 6731篇 |
神经病学 | 38217篇 |
特种医学 | 15993篇 |
外国民族医学 | 55篇 |
外科学 | 57573篇 |
综合类 | 4207篇 |
现状与发展 | 1篇 |
一般理论 | 130篇 |
预防医学 | 43485篇 |
眼科学 | 7207篇 |
药学 | 24627篇 |
2篇 | |
中国医学 | 1440篇 |
肿瘤学 | 31478篇 |
出版年
2023年 | 1480篇 |
2022年 | 2703篇 |
2021年 | 5426篇 |
2020年 | 3661篇 |
2019年 | 5444篇 |
2018年 | 28296篇 |
2017年 | 22054篇 |
2016年 | 24031篇 |
2015年 | 6974篇 |
2014年 | 8820篇 |
2013年 | 11530篇 |
2012年 | 23320篇 |
2011年 | 37379篇 |
2010年 | 27026篇 |
2009年 | 19027篇 |
2008年 | 32528篇 |
2007年 | 35382篇 |
2006年 | 14224篇 |
2005年 | 16014篇 |
2004年 | 16532篇 |
2003年 | 16333篇 |
2002年 | 12306篇 |
2001年 | 6661篇 |
2000年 | 6739篇 |
1999年 | 5768篇 |
1998年 | 2497篇 |
1997年 | 2052篇 |
1996年 | 1876篇 |
1995年 | 1677篇 |
1994年 | 1573篇 |
1993年 | 1414篇 |
1992年 | 3421篇 |
1991年 | 3317篇 |
1990年 | 3086篇 |
1989年 | 2962篇 |
1988年 | 2688篇 |
1987年 | 2472篇 |
1986年 | 2300篇 |
1985年 | 2212篇 |
1984年 | 1617篇 |
1983年 | 1334篇 |
1982年 | 843篇 |
1981年 | 724篇 |
1980年 | 722篇 |
1979年 | 1150篇 |
1978年 | 786篇 |
1977年 | 642篇 |
1975年 | 680篇 |
1974年 | 744篇 |
1973年 | 723篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Marcos Ribeiro Luciene Angelini Priscila Games Robles-Ribeiro Rafael Stelmach Ubiratan de Paula Santos Mario Terra-Filho 《The Journal of asthma》2007,44(5):371-375
Background. The European Community Respiratory Health Survey (ECRHS) questionnaire was planned to answer questions about the distribution of asthma. Our objective was to determine the cultural equivalence of the ECRHS into the Brazilian-Portuguese language. Methods. We translated the ECRHS according to international criteria. Results. Small cultural adaptations were necessary. Among the 80 participating patients, the Cronbach indices were higher (0.98-1.00) and the Kappa indices varied from 0.77 to 1.00. Conclusion. The study suggests that the Brazilian version of the ECRHS is conceptually equivalent to the original and similarly reliable and may be used in international studies involving Portuguese-speaking respiratory patients. 相似文献
132.
Chronic intestinal pseudo-obstruction: manifestations, natural history and management 总被引:2,自引:0,他引:2
v. stanghellini r. f. cogliandro r. de giorgio g. barbara b. salvioli & r. corinaldesi 《Neurogastroenterology and motility》2007,19(6):440-452
Chronic intestinal pseudo-obstruction (CIPO) is a rare pathological condition characterized by a marked derangement of gut propulsive motility mimicking mechanical obstruction, in the absence of any lesion occluding the gut lumen. This disease is often associated with a disabling and potentially life-threatening complications and is still too often unrecognized even in referral centres. As a result, patients receive neither appropriate care nor recognition of their severe health condition. Medical and surgical therapies are often unsatisfactory and long-term outcome turns out to be poor in the vast majority of cases. This article focuses on the main clinical features, the management and long-term outcome of patients affected by CIPO, with particular emphasis on those aspects which remain a matter of debate. 相似文献
133.
134.
J J de Souza T Perlmann A A Herman O J Ransome R W Kantor 《Suid-Afrikaanse tydskrif vir geneeskunde》1987,71(11):690-692
The value of maternal C-reactive protein (CRP) levels as predictors of fetal and maternal infective morbidity and fetal mortality was assessed prospectively over a 6-month period in all cases of premature rupture of the fetal membranes or suspected premature labour. Statistical analysis of results showed that CRP at a level of 1.32 mg/dl is a sensitive marker of infective morbidity in mother and neonate. Furthermore, there was a significant association between raised CRP levels and low-birth-weight babies, suggesting that intra-uterine infection is a major cause of prematurity in the study population. 相似文献
135.
136.
Background
Reports on childhood cancer survivors estimated cumulative probability of developing secondary neoplasms vary from 3,3% to 25% at 25 years from diagnosis, and the risk of developing another cancer to several times greater than in the general population. 相似文献137.
138.
Thomas J Beck Anne C Looker Firas Mourtada Maithili M Daphtary Christopher B Ruff 《Journal of bone and mineral research》2006,21(9):1425-1432
Age trends in proximal femur stresses were evaluated by simulating a fall on the greater trochanter using femur geometry from hip DXA scans of 5334 white men and women in the NHANES III survey. Expansion of femur outer diameter seems to counter net bone loss so that stresses remain similar across age groups, but stresses are higher in older women than in older men. INTRODUCTION: The age decline in hip BMD is caused by both bone loss and expansion of outer diameter that increases the region size over which mass is measured in a DXA scan. Because expansion has an opposing effect on structural strength, it may be a homeostatic adaptation to net bone loss to ensure that load stresses are kept within a narrow range. MATERIALS AND METHODS: Age trends in femur stresses were evaluated with an engineering beam simulation of a fall on the greater trochanter. Hip geometry was extracted from hip DXA scans using the Hip Structure Analysis (HSA) software on 2613 non-Hispanic white men and 2721 women from the third National Health and Nutrition Examination Survey (NHANES III). Using body weight as load, stresses were computed on the inferior-medial and superior-lateral femur neck at its narrowest point and the medial and lateral shaft 2 cm distal to the midpoint of the lesser trochanter. Stresses and the underlying geometries in men and women >50 years oaf age were compared with those 20-49 years of age. RESULTS: Compared with men <50 years of age, stresses in older men were 6% lower on both surfaces of the shaft, 4% lower on the inferior-medial neck, and not different on the superior-lateral neck. In women >50 years of age, stresses on the proximal shaft and inferior-medial neck remained within 3% of young values but were 13% greater on the superior-lateral neck. Neck stresses in young women were lower on the superior-lateral than the inferior-medial neck, but lateral stress increased to the level on the medial surface in older women. Stresses were higher in women than in men, with a greater gender difference in those >50 years of age. CONCLUSIONS: We conclude that femur expansion has a homeostatic effect in men and women that opposes bone loss so that stresses change little with age. Because expansion preserves stresses with progressively less bone mass, the process may reduce structural stability in the femoral neck under fall conditions, especially in the elderly female. 相似文献
139.
Alcides José Branco Filho William Kondo Luis Sérgio Nassif Mariana Jorge Garcia Rafael de Almeida Tirapelle Carlos Marcelo Dotti 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2006,10(3):326-331
BACKGROUND: Gastrogastric fistula is a communication between the proximal gastric pouch and the distal gastric remnant, rarely described in the realm of bariatric procedures. The aim of this study was to review the existing literature about this topic and to demonstrate its laparoscopic treatment. METHODS: An extensive literature review found several articles reporting this complication. However, no citation was found describing the steps of the laparoscopic management of this situation. RESULTS: Gastrogastric fistula occurs in up to 6% of Roux-en-Y gastric bypasses. Two theories exist for fistula formation: (1) it is a technical complication derived from the incomplete division of the stomach during the creation of the pouch, and (2) it occurs after a staple-line failure, developing a leak with an abscess, which then drains into the distal stomach forming the fistula. Early symptoms include fever, tachycardia, and abdominal pain. Failure in weight loss is a late clinical sign observed in these patients. Diagnosis is based on radiologic study, upper endoscopy and computed tomography. When identified in the acute postoperative course, laparoscopic treatment is easy. Chronic fistulas are difficult to manage, and the laparoscopic approach is an alternative to open surgery. CONCLUSIONS: Gastrogastric fistula is a possible complication of Roux-en-Y gastric bypass and its laparoscopic treatment is feasible. 相似文献
140.
Najat C Daw Wayne L Furman Clinton F Stewart Lisa C Iacono Mark Krailo Mark L Bernstein Janet E Dancey Rose Anne Speights Susan M Blaney James M Croop Gregory H Reaman Peter C Adamson 《Journal of clinical oncology》2005,23(25):6172-6180
PURPOSE: Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors. PATIENTS AND METHODS: Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28). RESULTS: Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults. CONCLUSION: Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued. 相似文献