全文获取类型
收费全文 | 47853篇 |
免费 | 4399篇 |
国内免费 | 73篇 |
专业分类
耳鼻咽喉 | 612篇 |
儿科学 | 1320篇 |
妇产科学 | 1327篇 |
基础医学 | 6875篇 |
口腔科学 | 1275篇 |
临床医学 | 5855篇 |
内科学 | 8419篇 |
皮肤病学 | 615篇 |
神经病学 | 3796篇 |
特种医学 | 2293篇 |
外国民族医学 | 1篇 |
外科学 | 6182篇 |
综合类 | 867篇 |
一般理论 | 23篇 |
预防医学 | 5272篇 |
眼科学 | 1090篇 |
药学 | 3556篇 |
2篇 | |
中国医学 | 57篇 |
肿瘤学 | 2888篇 |
出版年
2021年 | 651篇 |
2019年 | 638篇 |
2018年 | 754篇 |
2017年 | 631篇 |
2016年 | 612篇 |
2015年 | 709篇 |
2014年 | 949篇 |
2013年 | 1471篇 |
2012年 | 2146篇 |
2011年 | 2219篇 |
2010年 | 1218篇 |
2009年 | 1015篇 |
2008年 | 1877篇 |
2007年 | 2020篇 |
2006年 | 2018篇 |
2005年 | 2010篇 |
2004年 | 1827篇 |
2003年 | 1679篇 |
2002年 | 1704篇 |
2001年 | 1605篇 |
2000年 | 1708篇 |
1999年 | 1448篇 |
1998年 | 666篇 |
1997年 | 553篇 |
1996年 | 545篇 |
1995年 | 548篇 |
1994年 | 475篇 |
1993年 | 485篇 |
1992年 | 1261篇 |
1991年 | 1170篇 |
1990年 | 1154篇 |
1989年 | 1099篇 |
1988年 | 1019篇 |
1987年 | 1015篇 |
1986年 | 936篇 |
1985年 | 931篇 |
1984年 | 719篇 |
1983年 | 641篇 |
1982年 | 455篇 |
1981年 | 402篇 |
1980年 | 418篇 |
1979年 | 658篇 |
1978年 | 527篇 |
1977年 | 421篇 |
1976年 | 408篇 |
1975年 | 389篇 |
1974年 | 451篇 |
1973年 | 439篇 |
1972年 | 450篇 |
1971年 | 423篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Prevention of travelers' diarrhea by the tablet formulation of bismuth subsalicylate 总被引:11,自引:0,他引:11
H L DuPont C D Ericsson P C Johnson J A Bitsura M W DuPont F J de la Cabada 《JAMA》1987,257(10):1347-1350
Within 48 hours of arrival in Mexico, 182 US students participated in a study to compare the efficacy of two dosages of bismuth subsalicylate (262 mg per tablet) as a prophylactic agent against diarrhea. The students were randomly assigned to receive two tablets (high dose) or one tablet (low dose) of bismuth subsalicylate four times daily or a placebo four times daily during a three-week period. Among these completing the trial, diarrhea (four or more unformed stools in 24 hours or three in eight hours, plus one other symptom) occurred in seven (14%) of 51 receiving the high-dose regimen compared with 15 (24%) of 63 receiving the low-dose regimen and 23 (40%) of 58 in the placebo group. Protection rates were 65% for high-dose and 40% for low-dose bismuth subsalicylate. Diarrhea caused by enterotoxigenic Escherichia coli was found in one student receiving the high-dose regimen, in no students receiving the low-dose regimen, and in seven placebo-treated subjects. Bismuth subsalicylate was well tolerated; the most common side effects were blackening of tongues and stools. Bismuth subsalicylate use in both dosages was associated with tinnitus at a low, clinically insignificant frequency of 1.2 days per 100 days of treatment. The dosage of two tablets of bismuth subsalicylate four times daily (2.1 g/d) appears to be a safe and effective means of reducing the occurrence of travelers' diarrhea among persons at risk for periods up to three weeks. 相似文献
52.
CT appearance of cervical lipoblastoma 总被引:1,自引:0,他引:1
W C Black J W Burke P S Feldman C M Johnson S Swanson 《Journal of computer assisted tomography》1986,10(4):696-698
We describe a case of lipoblastoma causing respiratory symptoms in an infant, where CT was useful in establishing the diagnosis and demonstrating the extent of involvement so that complete surgical resection could be planned. 相似文献
53.
Renal angiomyolipoma: 6 case reports and literature review 总被引:4,自引:0,他引:4
M J Malone P R Johnson B M Jumper P J Howard T B Hopkins J A Libertino 《The Journal of urology》1986,135(2):349-353
We report 6 cases of renal angiomyolipomas and review the pertinent literature concerning this disease. One case involved the rare association of tuberous sclerosis and pregnancy. Another patient without tuberous sclerosis had renal cell carcinoma and later suffered a contralateral angiomyolipoma. The pathological conditions of renal angiomyolipomas with and without tuberous sclerosis are discussed. Since angiomyolipomas present with multiple clinical similarities to renal cell carcinoma, the primary task for the clinician is to differentiate this hamartoma from carcinoma. The distinguishing characteristics and the clinical management of renal angiomyolipomas are discussed. 相似文献
54.
Theodore Colton Laurence Freedman Tony Johnson David MaChin 《Statistics in medicine》1989,8(6):639-639
55.
Dr. Carsten Rist T.R. Johnson A. Becker A.W. Leber A. Huber S. Busch C.R. Becker M.F. Reiser K. Nikolaou 《Der Radiologe》2007,47(4):287-294
In a newly developed dual-source computed tomography system (DSCT) the relation of heart rate and image quality and the possible advantages of the system’s superior temporal resolution in the evaluation of left ventricular parameters as compared to results of cardiac magnetic resonance imaging (MRI) were assessed. Coronary CT angiography was performed using a DSCT (Somatom Defintion, Siemens Medical Solutions, Forchheim, Germany) in 21 patients (mean age 62±8; 15 male, 6 female). Image quality of the coronary arteries, the heart valves, and the left ventricular myocardium was assessed using a three-point grading scale. Ten of these patients also underwent cardiac MRI for the assessment of left ventricular function, using a SSFP (steady-state free precession) sequence. Left ventricular ejection fractions (LV-EF), the end-systolic volumes (ESV), and the end-diastolic volumes (EDV) were measured employing MRI and DSCT datasets. The image quality ratings for the coronary arteries at the optimal reconstruction interval were diagnostic even in patients with high heart rates (1.42±0.49). Analysis of global LV function using DSCT quantified from CTA datasets showed a good correlation with results of cardiac MRI [EF: r=0.75 (p=0.01); ESV: r=0.72 (p=0.19); EDV: r=0.71 (p=0.02)]. The dual-source CT system offers robust image quality of the coronary arteries, independent of the heart rate, and provides combined diagnostic imaging of coronary arteries, the heart valves, the myocardium, and the global left ventricular function. 相似文献
56.
57.
58.
59.
One of the few disinfectants known to inactivate the causative agent of Creutzfeldt-Jakob Disease is NaOH. In this study, NaOH was evaluated as a possible routine treatment for human dura mater alloimplants. Use of high concentration NaOH (1 M) resulted in protein loss and macroscopic changes to the tissue. Lower concentrations (0.1 M), although exhibiting little direct detrimental effect, greatly increased the susceptibility of the tissue to collagenase digestion. The use of NaOH treated commercial or institutionally prepared human dura mater should be approached with caution. 相似文献
60.
STUDY OBJECTIVE: To compare the diagnostic processes of experienced emergency physicians with those of novices. DESIGN: Prospective, convenience sample of patients. SETTING: Emergency department of a county university medical center in a large southwestern urban community. PARTICIPANTS: Experienced emergency physicians (attending and senior residents) and novice clinicians (junior residents and senior medical students). INTERVENTIONS: Participants developed initial diagnostic impressions after reviewing the chief complaint, nurse triage notes, and vital signs. Tests were then selected, and a final diagnostic impression was identified after results were known. Clinicians also marked a visual analog scale corresponding to their estimate that each diagnostic possibility was correct. RESULTS: Experienced physicians increased their certainty more than novices (P = .014). They deviated from a standard history-physical-laboratory sequence more often than novices (P = .008). CONCLUSION: Expertise in medical decision making is characterized by a moderate initial level of certainty concerning a diagnosis that significantly increases as the experienced clinician follows a flexible strategy of testing to arrive at a final diagnosis. 相似文献