全文获取类型
收费全文 | 271410篇 |
免费 | 20134篇 |
国内免费 | 1142篇 |
专业分类
耳鼻咽喉 | 2986篇 |
儿科学 | 7174篇 |
妇产科学 | 5106篇 |
基础医学 | 35835篇 |
口腔科学 | 5095篇 |
临床医学 | 27578篇 |
内科学 | 56821篇 |
皮肤病学 | 3699篇 |
神经病学 | 25689篇 |
特种医学 | 9087篇 |
外国民族医学 | 14篇 |
外科学 | 41076篇 |
综合类 | 3861篇 |
一般理论 | 341篇 |
预防医学 | 23775篇 |
眼科学 | 6879篇 |
药学 | 18569篇 |
6篇 | |
中国医学 | 452篇 |
肿瘤学 | 18643篇 |
出版年
2023年 | 1403篇 |
2022年 | 2511篇 |
2021年 | 5627篇 |
2020年 | 3406篇 |
2019年 | 5513篇 |
2018年 | 6264篇 |
2017年 | 4661篇 |
2016年 | 5170篇 |
2015年 | 6098篇 |
2014年 | 8976篇 |
2013年 | 12326篇 |
2012年 | 18783篇 |
2011年 | 19718篇 |
2010年 | 11035篇 |
2009年 | 9843篇 |
2008年 | 17308篇 |
2007年 | 18229篇 |
2006年 | 18132篇 |
2005年 | 18085篇 |
2004年 | 16959篇 |
2003年 | 15786篇 |
2002年 | 14784篇 |
2001年 | 2892篇 |
2000年 | 2406篇 |
1999年 | 3023篇 |
1998年 | 3338篇 |
1997年 | 2805篇 |
1996年 | 2450篇 |
1995年 | 2334篇 |
1994年 | 1961篇 |
1993年 | 1763篇 |
1992年 | 1828篇 |
1991年 | 1634篇 |
1990年 | 1489篇 |
1989年 | 1409篇 |
1988年 | 1383篇 |
1987年 | 1371篇 |
1986年 | 1361篇 |
1985年 | 1338篇 |
1984年 | 1517篇 |
1983年 | 1364篇 |
1982年 | 1551篇 |
1981年 | 1488篇 |
1980年 | 1306篇 |
1979年 | 982篇 |
1978年 | 955篇 |
1977年 | 803篇 |
1976年 | 740篇 |
1975年 | 632篇 |
1974年 | 663篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
33.
34.
These researchers investigated the effects of a progressive resistive, cycle ergometric exercise program on cardio-vascular endurance in one rheumatoid arthritic. The 46 yr. old, male subject exercised three days/week for 14 weeks. Workouts included interval-type training using 5 minute intervals for a total of 20-30 minutes (work rate set at 50-75 watts for each interval), not including 3-minute warm-up and cool-down periods (work rate set at zero resistance). Maximal exercise stress testing on the cycle ergometer was completed and blood samples collected before and after the exercise program. Also, psychological and physical health and lifestyle data were gathered before, during and after completion of the program. The conditioning program produced a training effect (greater than 75% of the HR max after the second exercise session) and blood values improved (10-28%) from the beginning to the end of the program. Finally, the program appeared to have a positive influence on various physical and psychological parameters as perceived by the subject and his wife. 相似文献
35.
Dr. Robert L. Geggel David R. Fulton Harvey L. Chernoff Richard Cleveland Thomas J. Hougen 《Pediatric cardiology》1987,8(4):279-283
Summary An infant girl is described who had cor triatriatum and partial anomalous pulmonary venous connection of the left pulmonary
veins to the coronary sinus, the first report of this combination of lesions. The infant also had a Dandy-Walker malformation
and multiple facial and intrathoracic hemangiomas. The cardiac diagnosis was made by two-dimensional echocardiography. Cardiac
catheterization and angiography confirmed the findings and also demonstrated a persistent left superior vena cava draining
to the coronary sinus. The infant underwent successful surgical repair. Partial anomalous pulmonary venous connection and
left superior vena cava not infrequently are associated with cor triatriatum. Although two-dimensional echocardiography is
sensitive for the detection of cor triatriatum, preoperative cardiac catheterization is necessary to identify unequivocally
systemic and pulmonary venous connections. 相似文献
36.
The interaction of the monoamine oxidase inhibitor pargyline with cultured hepatocytes has been studied. [Phenyl-3, benzyl-3H] pargyline (38 nM) rapidly enters the cells and a plateau of incorporation into a trichloroacetic acid insoluble form (monoamine oxidase) is reached after 2 hr. The level of labelling is lower in freshly isolated cells than in those in later culture. The maximum incorporation accounts for only 6% of the added radioactivity and produces a 9% inhibition of monoamine oxidase activity. The remaining [3H] pargyline is metabolized and quickly accumulates in the cell culture medium in a form which cannot label exogenous mitochondria. The metabolism of pargyline varies both qualitatively and quantitatively with culture age. In 0 hr and 20 hr-cultured cells one metabolite preferentially appears whilst in 140 hr cultured hepatocytes at least three metabolites are formed. The metabolism of [3H] pargyline in early culture is consistent with a cytochrome P-450 involvement. The use of [3H] pargyline to label monoamine oxidase in cultured hepatocytes offers several attractive features for studying the turnover of this enzyme. These include speed of interaction, non-reutilization, application to normal cells, controlled inhibition of monoamine oxidase and metabolism of non-specific label. 相似文献
37.
A two-week elective to introduce first- and second-year medical students to primary care internal medicine was developed and evaluated. Course time is divided between conference sessions (25 percent) provided by full-time clinical faculty members and office experience (75 percent) provided by volunteer clinical faculty members (general internists in private practice and in prepaid health plans). Evaluations by the students (n = 58) who took the elective consisted of a questionnaire assessment of the conference session topics, the student's ability to carry out course objectives, and the preceptor's teaching activities. The conference topics were highly rated, with a mean score of 4.1 on a rating scale ranging from 1 (unfavorable) to 5 (favorable). The course objectives and teaching activities were also well rated, with a mean score of 4.1 and 3.9, respectively, on a rating scale ranging from 1 (none) to 5 (outstanding). 相似文献
38.
39.
Lucy Yardley David Papo Adolfo Bronstein Michael Gresty Mark Gardner Nilli Lavie Linda Luxon 《Neuropsychologia》2002,40(4):373-383
The aim of this series of experiments was to determine whether attention is normally required for continuously processing vestibular information concerning orientation, or is required only when orientation is disrupted (eg by vestibular dysfunction or by conflicting visual and vestibular orientation cues). In the first two studies, healthy subjects were passively oscillated, and indicated when they perceived they were passing through their starting position. There was only weak evidence for interference between performance on this 'continuous orientation monitoring task' and on concurrent mental tasks. However, a third study showed that when patients with vestibular imbalance carried out the continuous orientation monitoring task their performance on a concurrent mental arithmetic task was substantially impaired. This dual task interference was correlated with inaccuracy in judging orientation on the continuous orientation monitoring task, which in turn correlated with severity of recent vestibular symptomatology (assessed by questionnaire). In a fourth experiment, disorientation was induced in healthy subjects by rotating the visual field about the line of sight. Bidirectional interference was observed between monitoring orientation (assessed by accuracy in setting a rod to the perceived vertical) and performance of an arithmetic task. Dual task interference was correlated with baseline levels of disorientation induced by the visual field, as indicated by inaccuracy in judging the visual vertical. These findings suggest that monitoring orientation makes significant demands upon cortical processing resources when disorientation is induced, whether the disorientation results from deficient sensory functioning or from ambiguous perceptual information. 相似文献
40.
The efficacy of radiology in evaluating dysphagia was studied in 86 patients by comparison to endoscopic findings. In the 66 patients with endoscopic abnormalities radiology was correct in 54, for a sensitivity of 82%. Sensitivity of radiology improved to 95% if mild esophagitis was excluded. In the 20 patients with normal endoscopy, radiology was normal in 18 (90%). Thus radiology proved to be a reliable means of evaluating the esophagus in patients with dysphagia. 相似文献