全文获取类型
收费全文 | 4618篇 |
免费 | 341篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 129篇 |
妇产科学 | 64篇 |
基础医学 | 1129篇 |
口腔科学 | 36篇 |
临床医学 | 350篇 |
内科学 | 690篇 |
皮肤病学 | 139篇 |
神经病学 | 740篇 |
特种医学 | 136篇 |
外科学 | 538篇 |
综合类 | 37篇 |
一般理论 | 2篇 |
预防医学 | 256篇 |
眼科学 | 100篇 |
药学 | 270篇 |
中国医学 | 8篇 |
肿瘤学 | 273篇 |
出版年
2023年 | 27篇 |
2022年 | 59篇 |
2021年 | 99篇 |
2020年 | 66篇 |
2019年 | 90篇 |
2018年 | 119篇 |
2017年 | 101篇 |
2016年 | 111篇 |
2015年 | 130篇 |
2014年 | 130篇 |
2013年 | 218篇 |
2012年 | 298篇 |
2011年 | 278篇 |
2010年 | 165篇 |
2009年 | 151篇 |
2008年 | 282篇 |
2007年 | 245篇 |
2006年 | 247篇 |
2005年 | 222篇 |
2004年 | 211篇 |
2003年 | 172篇 |
2002年 | 161篇 |
2001年 | 73篇 |
2000年 | 82篇 |
1999年 | 58篇 |
1998年 | 35篇 |
1997年 | 29篇 |
1996年 | 21篇 |
1992年 | 28篇 |
1991年 | 28篇 |
1990年 | 29篇 |
1989年 | 35篇 |
1988年 | 24篇 |
1987年 | 30篇 |
1986年 | 37篇 |
1985年 | 26篇 |
1984年 | 26篇 |
1941年 | 32篇 |
1940年 | 43篇 |
1939年 | 30篇 |
1938年 | 31篇 |
1937年 | 38篇 |
1936年 | 25篇 |
1933年 | 35篇 |
1929年 | 27篇 |
1928年 | 33篇 |
1927年 | 40篇 |
1926年 | 28篇 |
1925年 | 38篇 |
1924年 | 22篇 |
排序方式: 共有4967条查询结果,搜索用时 31 毫秒
51.
52.
Primary metastatic osteosarcoma: presentation and outcome of patients treated on neoadjuvant Cooperative Osteosarcoma Study Group protocols. 总被引:4,自引:0,他引:4
Leo Kager Andreas Zoubek Ulrike P?tschger Ulrike Kastner Silke Flege Beate Kempf-Bielack Detlev Branscheid Rainer Kotz Mechthild Salzer-Kuntschik Winfried Winkelmann Gernot Jundt Hartmut Kabisch Peter Reichardt Heribert Jürgens Helmut Gadner Stefan S Bielack 《Journal of clinical oncology》2003,21(10):2011-2018
PURPOSE: To determine demographic data and define prognostic factors for long-term outcome in patients presenting with high-grade osteosarcoma of bone with clinically detectable metastases at initial presentation. PATIENTS AND METHODS: Of 1,765 patients with newly diagnosed, previously untreated high-grade osteosarcomas of bone registered in the neoadjuvant Cooperative Osteosarcoma Study Group studies before 1999, 202 patients (11.4%) had proven metastases at diagnosis and therefore were enrolled onto an analysis of demographic-, tumor-, and treatment-related variables, response, and survival. The intended therapeutic strategy included pre- and postoperative multiagent chemotherapy as well as aggressive surgery of all resectable lesions. RESULTS: With a median follow-up of 1.9 years (5.5 years for survivors), 60 patients were alive, 37 of whom were in continuously complete surgical remission. Actuarial overall survival rates at 5 and 10 (same value for 15) years were 29% (SE = 3%) and 24% (SE = 4%), respectively. In univariate analysis, survival was significantly correlated with patient age, site of the primary tumor, number and location of metastases, number of involved organ systems, histologic response of the primary tumor to preoperative chemotherapy, and completeness and time point of surgical resection of all tumor sites. However, after multivariate Cox regression analysis, only multiple metastases at diagnosis (relative hazard rate [RHR] = 2.3) and macroscopically incomplete surgical resection (RHR = 2.4) remained significantly associated with inferior outcomes. CONCLUSION: The number of metastases at diagnosis and the completeness of surgical resection of all clinically detected tumor sites are of independent prognostic value in patients with proven primary metastatic osteosarcoma. 相似文献
53.
Toshifumi Ozaki Silke Flege Matthias Kevric Norbert Lindner Rainer Maas Günter Delling Rudolf Schwarz Arthur R von Hochstetter Mechthild Salzer-Kuntschik Wolfgang E Berdel Heribert Jürgens G Ulrich Exner Peter Reichardt Regine Mayer-Steinacker Volker Ewerbeck Rainer Kotz Winfried Winkelmann Stefan S Bielack 《Journal of clinical oncology》2003,21(2):334-341
PURPOSE: To define patients and tumor characteristics as well as therapy results, patients with pelvic osteosarcoma who were registered in the Cooperative Osteosarcoma Study Group (COSS) were analyzed. PATIENTS AND METHODS: Sixty-seven patients with a high-grade pelvic osteosarcoma were eligible for this analysis. Fifteen patients had primary metastases. All patients received chemotherapy according to COSS protocols. Thirty-eight patients underwent limb-sparing surgery, 12 patients underwent hemipelvectomy, and 17 patients did not undergo definitive surgery. Eleven patients received irradiation to the primary tumor site: four postoperatively and seven as the only form of local therapy. RESULTS: Local failure occurred in 47 of all 67 patients (70%) and in 31 of 50 patients (62%) who underwent definitive surgery. Five-year overall survival (OS) and progression-free survival rates were 27% and 19%, respectively. Large tumor size (P =.0137), primary metastases (P =.0001), and no or intralesional surgery (P <.0001) were poor prognostic factors. In 30 patients with no or intralesional surgery, 11 patients with radiotherapy had better OS than 19 patients without radiotherapy (P =.0033). Among the variables, primary metastasis, large tumor, no or intralesional surgery, no radiotherapy, existence of primary metastasis (relative risk [RR] = 3.456; P =.0009), surgical margin (intralesional or no surgical excision; RR = 5.619; P <.0001), and no radiotherapy (RR = 4.196; P =.0059) were independent poor prognostic factors. CONCLUSION: An operative approach with wide or marginal margins improves local control and OS. If the surgical margin is intralesional or excision is impossible, additional radiotherapy has a positive influence on prognosis. 相似文献
54.
Cardiac performance after deep hypothermic circulatory arrest in chronically cyanotic neonatal lambs 总被引:2,自引:0,他引:2
Nagashima M Nollert G Stock U Sperling J Hatsuoka S Shum-Tim D Takeuchi K Nedder A Mayer JE 《The Journal of thoracic and cardiovascular surgery》2000,120(2):238-246
OBJECTIVES: It is controversial whether immature cyanotic hearts are more susceptible to ischemic injury than normoxemic hearts. Acutely induced alveolar hypoxic stress before cardiopulmonary bypass has been used as a model of cyanosis and is reported to worsen recovery of immature hearts after subsequent ischemic insult by means of a free radical injury mechanism. Because of concerns about the relevance of acute alveolar repair to the chronic cyanosis encountered clinically, we assessed the effects of chronic cyanosis without alveolar hypoxia, acute alveolar hypoxia, and normoxemia on recovery of cardiac function after deep hypothermic circulatory arrest. METHODS: A chronic cyanosis model was created in 8 lambs by an anastomosis between the pulmonary artery and the left atrium (cyanosis group). Eight lambs underwent sham operation (control). One week later, the animals underwent cardiopulmonary bypass with 90 minutes of deep hypothermic circulatory arrest at 18 degrees C. Another 8 lambs underwent 45 minutes of hypoxic ventilation before bypass, with arterial oxygen tension being maintained at 30 mm Hg (acute hypoxia group). Cardiac index, preload recruitable stroke work, and tau were measured. Malondialdehyde and nitrate-nitrite, nitric oxide metabolites, were also measured in the coronary sinus. Myocardial antioxidant reserve capacity at 2 hours of reperfusion was assessed by measuring lipid peroxidation in left ventricular tissue samples incubated with t-butylhydroperoxide at 37 degrees C. RESULTS: Oxygen tension was 35 +/- 3 mm Hg in the acute hypoxia group versus 93 +/- 7 mm Hg in the control group. In the acute hypoxia group the recovery of cardiac index, preload recruitable stroke work, and tau were significantly worse than that found in both the control and cyanosis groups. Preload recruitable stroke work at 2 hours of reperfusion was slightly but significantly lower in the cyanosis group than in the control group. The postischemic level of nitric oxide metabolites was significantly lower in the acute hypoxia group than in the cyanosis and control groups. However, malondialdehyde levels in the coronary sinus and myocardial antioxidant reserve capacity were not significantly different among the groups. CONCLUSION: Recovery of left ventricular function after deep hypothermic circulatory arrest in neonatal lambs with chronic cyanosis was slightly worse than that found in acyanotic animals. Acute hypoxia before bypass was associated with significantly worse recovery of left ventricular function, and the mechanism of injury may be related to an impairment of nitric oxide production. Free radical injury does not appear to explain any differences among cyanotic, acyanotic, and acutely hypoxic animals in recovery of left ventricular function after ischemia. 相似文献
55.
56.
Establishing a definitive diagnosis for any form of alopecia can be challenging. Adding to the diagnostic complexity is the fact that many patients have more than one form of alopecia contributing to their hair loss. We conducted a review of 1360 consecutive scalp biopsy specimens submitted for the evaluation of scalp hair loss over a 16‐month period, demonstrating that 12.5% of cases had a combination of diagnoses (multifactorial alopecia) accounting for their hair loss. An approach to the histopathologic diagnosis of multifactorial alopecia, particularly multiple forms of alopecia found in a single biopsy, is here presented. 相似文献
57.
58.
59.
60.
Ashley Sharp Berit Muller-Pebody Andre Charlett Bharat Patel Rebecca Gorton Jonathan Lambourne Martina Cummins Adela Alcolea-Medina Mark Wilks Robin Smith Damien Mack Susan Hopkins Andrew Dodgson Phillipa Burns Nelun Perera Felicia Lim Gopal Rao Priya Khanna Elizabeth Johnson Andrew Borman Silke Schelenz Rebecca Guy Joanna Conneely Rohini J Manuel Colin S Brown 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2021,26(8)
Background Candida auris is an emerging multidrug-resistant fungal pathogen associated with bloodstream, wound and other infections, especially in critically ill patients. C. auris carriage is persistent and is difficult to eradicate from the hospital environment.AimWe aimed to pilot admission screening for C. auris in intensive care units (ICUs) in England to estimate prevalence in the ICU population and to inform public health guidance.MethodsBetween May 2017 and April 2018, we screened admissions to eight adult ICUs in hospitals with no previous cases of C. auris, in three major cities. Swabs were taken from the nose, throat, axilla, groin, perineum, rectum and catheter urine, then cultured and identified using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Patient records were linked to routine ICU data to describe and compare the demographic and health indicators of the screened cohort with a national cohort of ICU patients admitted between 2016 and 2017.ResultsAll C. auris screens for 921 adults from 998 admissions were negative. The upper confidence limit of the pooled prevalence across all sites was 0.4%. Comparison of the screened cohort with the national cohort showed it was broadly similar to the national cohort with respect to demographics and co-morbidities.ConclusionThese findings imply that C. auris colonisation among patients admitted to ICUs in England is currently rare. We would not currently recommend widespread screening for C. auris in ICUs in England. Hospitals should continue to screen high-risk individuals based on local risk assessment. 相似文献