全文获取类型
收费全文 | 2142篇 |
免费 | 203篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 70篇 |
妇产科学 | 56篇 |
基础医学 | 340篇 |
口腔科学 | 41篇 |
临床医学 | 224篇 |
内科学 | 280篇 |
皮肤病学 | 32篇 |
神经病学 | 154篇 |
特种医学 | 171篇 |
外科学 | 302篇 |
综合类 | 29篇 |
一般理论 | 1篇 |
预防医学 | 221篇 |
眼科学 | 22篇 |
药学 | 194篇 |
中国医学 | 5篇 |
肿瘤学 | 180篇 |
出版年
2022年 | 16篇 |
2021年 | 25篇 |
2020年 | 15篇 |
2019年 | 26篇 |
2018年 | 28篇 |
2017年 | 36篇 |
2016年 | 35篇 |
2015年 | 45篇 |
2014年 | 45篇 |
2013年 | 62篇 |
2012年 | 96篇 |
2011年 | 89篇 |
2010年 | 59篇 |
2009年 | 60篇 |
2008年 | 96篇 |
2007年 | 124篇 |
2006年 | 87篇 |
2005年 | 111篇 |
2004年 | 94篇 |
2003年 | 76篇 |
2002年 | 87篇 |
2001年 | 64篇 |
2000年 | 93篇 |
1999年 | 96篇 |
1998年 | 24篇 |
1997年 | 22篇 |
1996年 | 25篇 |
1995年 | 14篇 |
1993年 | 22篇 |
1992年 | 55篇 |
1991年 | 50篇 |
1990年 | 37篇 |
1989年 | 42篇 |
1988年 | 27篇 |
1987年 | 33篇 |
1986年 | 26篇 |
1985年 | 35篇 |
1984年 | 25篇 |
1983年 | 15篇 |
1981年 | 17篇 |
1979年 | 23篇 |
1978年 | 30篇 |
1977年 | 16篇 |
1976年 | 21篇 |
1975年 | 17篇 |
1974年 | 15篇 |
1973年 | 16篇 |
1972年 | 18篇 |
1970年 | 24篇 |
1967年 | 13篇 |
排序方式: 共有2347条查询结果,搜索用时 15 毫秒
21.
Self-medication with anabolic steroids by athletes, particularly in the sports of weight lifting and track and field, has become increasingly popular. In the 1983 Pan American Games, 15 athletes were disqualified for taking anabolic steroids. Athletes take steroids believing the steroids will allow increased periods of intensive training and will increase muscle strength with proper weight training. The athletes assume this increased strength and training will translate into better athletic performance. Most athletes taking anabolic steroids are taking very large doses with no thought as to the potential adverse side effects. They ignore the possibility of long-term problems relating to hypertension, liver dysfunction, and atherosclerosis for what they see as the immediate performance benefits. In an attempt to keep sports competition "clean" and to help protect athletes from harmful drugs, the International Olympic Committee (IOC) and the United States Olympic Committee have rules stating that the use of anabolic steroids is illegal. Drug testing is performed in Olympic and in many international competitions. Those people found using anabolic steroids are disqualified. This use of anabolic steroids indicates that for some athletes the need to win or to maximize performance supersedes any worries about future health. 相似文献
22.
Nonoperative Management of Primary Colorectal Cancer in Patients With Stage IV Disease 总被引:12,自引:0,他引:12
Scoggins CR Meszoely IM Blanke CD Beauchamp RD Leach SD 《Annals of surgical oncology》1999,6(7):651-657
Background: Traditional teaching maintains that patients with primary colorectal adenocarcinoma require timely resection to prevent bleeding, perforation, or obstruction. The true benefits of primary tumor resection remain undocumented for patients presenting with metastatic disease, however. We postulated that resection of primary colorectal tumors could be avoided safely in a select population of asymptomatic colorectal cancer patients presenting with incurable stage IV disease.Methods: A retrospective review of the Vanderbilt University Hospital tumor registry was performed for the years 1985 to 1997. During this period, 955 patients presented for management of primary colorectal cancer. From this group, all patients with stage IV disease at the time of diagnosis were identified. Patients who initially underwent resection of their primary lesion were included in the resection group; those who underwent initial nonoperative primary tumor management were included in the nonresection group. Data were obtained regarding age, extent of disease, nonsurgical therapy, tumor-specific complications, and palliative surgical procedures. Surgery-free survival and overall survival were analyzed using the Kaplan-Meier method. For patients with liver metastases, hepatic tumor burden was defined as either H1 (<25% parenchymal replacement), H2 (25% to 50%), or H3 (>50%) disease.Results: Sixty-six patients were included in the resection group, and 23 patients with intact asymptomatic primary colorectal lesions were included in the nonresection group. Among patients with hepatic metastases, most of the patients in both groups had H1 disease. Ten patients in the resection group and 3 patients in the nonresection group presented with exclusively extrahepatic metastases. In the nonresection group, primary therapy included chemotherapy in 13 patients, external beam radiation therapy in 1 patient, and combination chemoradiation in 9 patients. The median survival in the nonresection group was 16.6 months. The 2-year actuarial survival was 18%, and the surgery-free survival was 91.3%. Only 2 of 23 patients (8.7%) managed without resection eventually developed obstruction at the primary tumor site requiring emergent diversion. There were no episodes of tumor-related hemorrhage or perforation. For the resection group, the operative morbidity was 30.3%, and the perioperative mortality rate was 4.6%. The median survival in the resection group was 14.5 months (P = 0.59, log-rank test vs. nonresection group).Conclusions: Selected patients with asymptomatic primary colorectal tumors who present with incurable metastatic disease may safely avoid resection of their primary lesions, with an anticipated low rate of hemorrhage, perforation, or obstruction before death from systemic disease. No survival advantage is gained by resection of an asymptomatic primary lesion in the setting of incurable stage IV colorectal cancer. 相似文献
23.
24.
Beatrice M Seddon Geoffrey S Payne Laura Simmons Ruth Ruddle Rachel Grimshaw Siew Tan Alison Turner Florence Raynaud Gavin Halbert Martin O Leach Ian Judson Paul Workman 《Clinical cancer research》2003,9(14):5101-5112
PURPOSE: To perform a Phase I study of SR-4554, a fluorinated 2-nitroimidazole noninvasive probe of tumor hypoxia detected by (19)F magnetic resonance spectroscopy (MRS). EXPERIMENTAL DESIGN: SR-4554 administration, on days 1 and 8, was followed by plasma sampling for pharmacokinetic studies and by three MRS studies performed over 24 h on days 8 and 9. Unlocalized MR spectra were acquired from tumor (10- or 16-cm dual resonant 1H/19F surface coil; 1.5 T Siemens Vision MR system; 2048 transients acquired over 34 min; 1.28-ms adiabatic pulse; repetition time, 1 s). Plasma drug concentrations were measured with a validated high-performance liquid chromatography method. Noncompartmental pharmacokinetic analysis was performed. RESULTS: Eight patients underwent pharmacokinetic studies, receiving doses of SR-4554 of 400-1600 mg/m(2). Peak plasma concentrations increased linearly with the SR-4554 dose (r(2) = 0.80; P = 0.0002). The plasma elimination half-life was relatively short (mean +/- SD, 3.28 +/- 0.59 h), and plasma clearance was quite rapid (mean +/- SD, 12.8 +/- 3.3 liters/h). Urinary recovery was generally high. SR-4554 was well tolerated. A single patient experienced dose-limiting toxicity (nausea and vomiting) at 1600 mg/m(2). The maximum tolerated dose was 1400 mg/m(2). SR-4554 was detected spectroscopically in tumors immediately after infusion at doses of 400-1600 mg/m(2). At the highest dose (1600 mg/m(2)), SR-4554 was detectable in tumor at 8 h, but not at 27 h. CONCLUSIONS: SR-4554 has plasma pharmacokinetic and toxicity profiles suitable for use as a hypoxia probe. It can be detected in tumors by unlocalized MRS. Additional clinical studies are warranted. 相似文献
25.
26.
27.
28.
29.
Watterberg KL Shaffer ML Garland JS Thilo EH Mammel MC Couser RJ Aucott SW Leach CL Cole CH Gerdes JS Rozycki HJ Backstrom C 《The Journal of clinical endocrinology and metabolism》2005,90(12):6380-6385
CONTEXT: Various cosyntropin doses are used to test adrenal function in premature infants, without consensus on appropriate dose or adequate response. OBJECTIVE: The objective of this study was to test the cortisol response of extremely low birth weight infants to different cosyntropin doses and evaluate whether these doses differentiate between groups of infants with clinical conditions previously associated with differential response to cosyntropin. DESIGN: The design was a prospective, nested study conducted within a randomized clinical trial of low-dose hydrocortisone from November 1, 2001, to April 30, 2003. SETTING: The setting was nine newborn intensive care units. PATIENTS: The patients included infants with 500-999 g birth weight. INTERVENTION: The drug used was cosyntropin, at 1.0 or 0.1 microg/kg, given between 18 and 28 d of birth. MAIN OUTCOME MEASURE: We measured the cortisol response to cosyntropin. RESULTS: Two hundred seventy-six infants were tested. Previous hydrocortisone treatment did not suppress basal or stimulated cortisol values. Cosyntropin, at 1.0 vs. 0.1 microg/kg, yielded higher cortisol values (P < 0.001) and fewer negative responses (2 vs. 21%). The higher dose, but not the lower dose, showed different responses for girls vs. boys (P = 0.02), infants receiving enteral nutrition vs. not (P < 0.001), infants exposed to chorioamnionitis vs. not (P = 0.04), and those receiving mechanical ventilation vs. not (P = 0.02), as well as a positive correlation with fetal growth (P = 0.03). A response curve for the 1.0-microg/kg dose for infants receiving enteral nutrition (proxy for clinically well infants) showed a 10th percentile of 16.96 microg/dl. Infants with responses less than the 10th percentile had more bronchopulmonary dysplasia and longer length of stay. CONCLUSIONS: A cosyntropin dose of 0.1 microg/kg did not differentiate between groups of infants with clinical conditions that affect response. We recommend 1.0 microg/kg cosyntropin to test adrenal function in these infants. 相似文献