全文获取类型
收费全文 | 15117篇 |
免费 | 822篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 122篇 |
儿科学 | 283篇 |
妇产科学 | 345篇 |
基础医学 | 2310篇 |
口腔科学 | 386篇 |
临床医学 | 1383篇 |
内科学 | 3023篇 |
皮肤病学 | 266篇 |
神经病学 | 1352篇 |
特种医学 | 1162篇 |
外国民族医学 | 2篇 |
外科学 | 1932篇 |
综合类 | 107篇 |
一般理论 | 4篇 |
预防医学 | 795篇 |
眼科学 | 385篇 |
药学 | 1001篇 |
中国医学 | 24篇 |
肿瘤学 | 1128篇 |
出版年
2023年 | 58篇 |
2022年 | 142篇 |
2021年 | 264篇 |
2020年 | 139篇 |
2019年 | 200篇 |
2018年 | 232篇 |
2017年 | 199篇 |
2016年 | 255篇 |
2015年 | 306篇 |
2014年 | 437篇 |
2013年 | 537篇 |
2012年 | 846篇 |
2011年 | 854篇 |
2010年 | 519篇 |
2009年 | 503篇 |
2008年 | 866篇 |
2007年 | 900篇 |
2006年 | 872篇 |
2005年 | 845篇 |
2004年 | 819篇 |
2003年 | 809篇 |
2002年 | 793篇 |
2001年 | 442篇 |
2000年 | 388篇 |
1999年 | 347篇 |
1998年 | 193篇 |
1997年 | 186篇 |
1996年 | 117篇 |
1995年 | 107篇 |
1994年 | 80篇 |
1993年 | 85篇 |
1992年 | 172篇 |
1991年 | 176篇 |
1990年 | 153篇 |
1989年 | 169篇 |
1988年 | 135篇 |
1987年 | 136篇 |
1986年 | 106篇 |
1985年 | 119篇 |
1984年 | 94篇 |
1983年 | 85篇 |
1982年 | 62篇 |
1979年 | 98篇 |
1978年 | 68篇 |
1977年 | 64篇 |
1976年 | 62篇 |
1974年 | 82篇 |
1973年 | 70篇 |
1972年 | 59篇 |
1970年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Josh Greenstein Devjani Das Josie Acuna Monica Kapoor Cara Brown Abbas Husain Brendan Lally Barry Hahn 《The American journal of emergency medicine》2019,37(2):313-316
Background
In the emergency department, rib fractures are a common finding in patients who sustain chest trauma. Rib fractures may be a sign of significant, underlying pathology, especially in the elderly patients where rib fractures are associated with significant morbidity and mortality. To date, no studies have evaluated the ability of ultrasound to detect rib fractures using cadaver models and subsequently use this model as a teaching tool.Objectives
The purpose of this study was to determine if it is possible to generate rib fractures on cadaver models which could be accurately identified using ultrasound.Methods
This was a cross-sectional study performed during one session at a cadaver lab. A single hemithorax from four adult cadavers were used as models. Single rib fractures on each of rib five through eight were created. Four subjects, blinded to the normal versus fractured ribs, were asked to identify the presence of a fracture on each rib.Results
A total of 8 of 16 potential ribs had fractured induced by study staff. Mean accuracy was 55% for all subjects. The overall sensitivity and specificity for detecting rib fractures was 50% (CI: 31.89–68.11) and 59.38% (CI: 35.69–73.55) respectively. The overall PPV and NPV was 55.17% and 54.29% respectively.Conclusions
In this pilot study, subjects were not able to detect induced rib fractures using ultrasound on cadaver models. The use of this model as a teaching tool in the detection of rib fractures requires further investigation. 相似文献2.
Uwe Schneider PhD Antony Lomax Peter Pemler Jürgen Besserer Dieter Ross Norbert Lombriser Barbara Kaser-Hotz 《Strahlentherapie und Onkologie》2006,182(11):647-652
BACKGROUND AND PURPOSE: There is concern about the increase of radiation-induced malignancies with the application of modern radiation treatment techniques such as intensity-modulated radiotherapy (IMRT) and proton radiotherapy. Therefore, X-ray scatter and neutron radiation as well as the impact of the primary dose distribution on secondary cancer incidence are analyzed. MATERIAL AND METHODS: The organ equivalent dose (OED) concept with a linear-exponential and a plateau dose-response curve was applied to dose distributions of 30 patients who received radiation therapy of prostate cancer. Three-dimensional conformal radiotherapy was used in eleven patients, another eleven patients received IMRT with 6-MV photons, and eight patients were treated with spot-scanned protons. The treatment plans were recalculated with 15-MV and 18-MV photons. Secondary cancer risk was estimated based on the OED for the different treatment techniques. RESULTS: A modest increase of 15% radiation-induced cancer results from IMRT using low energies (6 MV), compared to conventional four-field planning with 15-MV photons (plateau dose-response: 1%). The probability to develop a secondary cancer increases with IMRT of higher energies by 20% and 60% for 15 MV and 18 MV, respectively (plateau dose-response: 2% and 30%). The use of spot-scanned protons can reduce secondary cancer incidence as much as 50% (independent of dose-response). CONCLUSION: By including the primary dose distribution into the analysis of radiation-induced cancer incidence, the resulting increase in risk for secondary cancer using modern treatment techniques such as IMRT is not as dramatic as expected from earlier studies. By using 6-MV photons, only a moderate risk increase is expected. Spot-scanned protons are the treatment of choice in regard to secondary cancer incidence. 相似文献
3.
4.
Edward M Messing Judith Manola George Wilding Kathleen Propert Jonathan Fleischmann E David Crawford J Edson Pontes Richard Hahn Donald Trump 《Journal of clinical oncology》2003,21(7):1214-1222
PURPOSE: To evaluate the role of adjuvant interferon alfa after complete resection of locally extensive renal cell carcinoma. PATIENTS AND METHODS: A total of 283 eligible patients with pT3-4a and/or node-positive disease were randomly assigned after radical nephrectomy and lymphadenectomy to observation or to interferon alfa-NL (Wellferon, Burroughs-Wellcome, Research Park, NC) given daily for 5 days every 3 weeks for up to 12 cycles. Patients were stratified on the basis of pathologic stage. Patients remained on treatment until documented recurrence, excessive toxicity, or patient/physician preference deemed removal appropriate. RESULTS: At median follow-up of 10.4 years, median survival was 7.4 years in the observation arm and 5.1 year in the treatment arm (log-rank P =.09). Median recurrence-free survival was 3.0 years in the observation arm and 2.2 years in the interferon arm (P =.33). Performance status (P =.003), nodal status (N2 v N0, P <.0001), and tumor stage (P =.0002) were significant prognostic factors in multivariate analysis. A proportional hazards model examining the effects of treatment arm and time to recurrence on survival after recurrence among patients who recurred found that random assignment to interferon treatment (P =.009) and shorter time to recurrence (P <.0001) were independent predictors of shorter survival after recurrence. Although no lethal toxicities were observed, severe (grade 4) toxicities including neutropenia, myalgia, fatigue, depression, and other neurologic toxicities occurred in 11.4% of those randomly assigned to interferon treatment. CONCLUSION: Adjuvant treatment with interferon did not contribute to survival or relapse-free survival in this group of patients. 相似文献
5.
6.
Effect of age and diet on cyclic nucleotide concentrations in the intestinal mucosa of developing rats 总被引:1,自引:0,他引:1
Mucosa isolated from the proximal third of the small intestine of infant rats had much lower cyclic nucleotide concentrations (expressed both per unit wet weight and per unit DNA content) than those determined in the intestinal wall. The steady-state concentrations of both cyclic AMP and cyclic GMP in jejunum showed dramatic increases during the first 5 d post partum. Another increase in cyclic nucleotide concentrations was observed in the isolated mucosa between d 15 and 21. Starvation for 24 h always resulted in lower intestinal cyclic nucleotide concentrations than those of the fed littermates. This effect was more pronounced in younger animals and more evident for cyclic AMP values. Three-week-old rats fed a high carbohydrate diet for 24-48 h exhibited more pronounced elevations in the concentrations of cyclic nucleotides from the jejunal mucosa than did rats fed a high fat diet. 相似文献
7.
Robert G. Hahn 《Journal canadien d'anesthésie》1995,42(1):69-72
The transurethral resection syndrome has not previously been described after bladder surgery. This article reports four patients who developed signs of this syndrome after transurethral resection of bladder tumours (TURB). Symptoms included abdominal pain, arterial hypotension, nausea and vomiting. There was evidence in all cases that the cause was absorption of irrigating fluid by the extravascular route. Fluid absorption was detected by ethanol in two patients and the urologist noted a perforation during the third operation. The most complicated clinical course occurred in the case where there was a delay of three hours before the diagnosis was made. Medical treatment consisted of antiemetics and volume expansion of the extracellular fluid compartment as extravasation is associated with hypovolaemia. Diuretics were not given until the circulation had been restored. 相似文献
8.
Conventional radiographs do not always make it possible to confirm a diagnosis of ischemic necrosis of the lunate in the early stages of disease. For these doubtful cases MRI is justifiable in addition, to diagnose or to rule out ischemic necrosis of the lunate. 相似文献
9.
When arthrodesis of the knee is indicated, the operative procedure selected for fixation depends on the condition of the soft tissues, the bone stock, whether infection is present, and the age of the patient and his or her capacity for partial weight-bearing. In young patients with no infection or soft tissue problems, when adequate bone stock is present compression plating or the use of an intramedullary nail is possible and allows stable fixation. Soft tissue problems with defect(s) or infection are a good indication for the use of an external fixator. The most common indication for knee arthrodesis is a failed total knee prosthesis that has become infected. Deficient bone stock with osteopenic bone or a defect after failed total knee arthroplasty are problems that can be solved by the use of modular fusion nail systems, especially in older patients. These systems are more comfortable for the patient than external fixation devices and allow early full weight-bearing. 相似文献
10.