全文获取类型
收费全文 | 712115篇 |
免费 | 49120篇 |
国内免费 | 1338篇 |
专业分类
耳鼻咽喉 | 9191篇 |
儿科学 | 23375篇 |
妇产科学 | 17686篇 |
基础医学 | 111034篇 |
口腔科学 | 20084篇 |
临床医学 | 64178篇 |
内科学 | 135930篇 |
皮肤病学 | 16227篇 |
神经病学 | 49940篇 |
特种医学 | 25975篇 |
外国民族医学 | 76篇 |
外科学 | 105571篇 |
综合类 | 14853篇 |
现状与发展 | 2篇 |
一般理论 | 160篇 |
预防医学 | 51518篇 |
眼科学 | 16696篇 |
药学 | 54291篇 |
3篇 | |
中国医学 | 2370篇 |
肿瘤学 | 43413篇 |
出版年
2021年 | 5531篇 |
2018年 | 7951篇 |
2017年 | 6197篇 |
2016年 | 6956篇 |
2015年 | 7661篇 |
2014年 | 10418篇 |
2013年 | 15540篇 |
2012年 | 20782篇 |
2011年 | 21769篇 |
2010年 | 12895篇 |
2009年 | 12082篇 |
2008年 | 20247篇 |
2007年 | 21775篇 |
2006年 | 22190篇 |
2005年 | 20709篇 |
2004年 | 20273篇 |
2003年 | 19223篇 |
2002年 | 18756篇 |
2001年 | 36539篇 |
2000年 | 37119篇 |
1999年 | 30577篇 |
1998年 | 7954篇 |
1997年 | 6725篇 |
1996年 | 7028篇 |
1995年 | 6683篇 |
1994年 | 6152篇 |
1993年 | 5634篇 |
1992年 | 23110篇 |
1991年 | 23067篇 |
1990年 | 22425篇 |
1989年 | 22212篇 |
1988年 | 20159篇 |
1987年 | 19496篇 |
1986年 | 18568篇 |
1985年 | 17396篇 |
1984年 | 12754篇 |
1983年 | 10802篇 |
1982年 | 5942篇 |
1979年 | 11583篇 |
1978年 | 8167篇 |
1977年 | 6871篇 |
1976年 | 6619篇 |
1975年 | 7295篇 |
1974年 | 8541篇 |
1973年 | 8184篇 |
1972年 | 7700篇 |
1971年 | 7182篇 |
1970年 | 6911篇 |
1969年 | 6342篇 |
1968年 | 5823篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
To investigate the simultaneous effects of dexamethasone on peripheral and central adrenocorticotropic hormone (ACTH) systems, rats were treated with dexamethasone or saline for 4 days. Pituitary, plasma, hypothalamus and cerebrospinal fluid (CSF) were then collected and analyzed for ACTH immunoreactivity. Additionally, hypothalamic tissue extracts were analyzed for corticotropin-releasing hormone (CRH) immunoreactivity. Dexamethasone significantly lowered peripheral levels of ACTH as measured in pituitary and plasma. Hypothalamic ACTH content significantly increased while CSF ACTH significantly decreased with dexamethasone treatment. Hypothalamic CRH concentrations showed a small but statistically insignificant decrease. These results suggest that prolonged exposure to dexamethasone affects central as well as peripheral ACTH activity, corroborate our previous findings in rhesus monkeys of decreased CSF ACTH in response to prolonged dexamethasone treatment, suggest that dexamethasone may inhibit the release of ACTH from hypothalamic neurons into the CSF, and provide evidence that the effect of dexamethasone on pituitary ACTH content is of greater magnitude than its effect on hypothalamic CRH. 相似文献
102.
V K Ryzhkov N A Borisova E M Gapchenko I A Dmitrieva 《Vestnik khirurgii imeni I. I. Grekova》1986,136(1):11-14
Roentgen endovascular occlusion with spiral emboli was used in 240 patients with different diseases. The introduction of spiral emboli into the arteries of abdominal and retroperitoneal organs was fulfilled through usual angiographic catheters. Duration of the arterial occlusion was checked up in the following angiographic examinations and showed the devices described to be appropriate for a continuous arterial blockade. No complications resulting from the introduction of the spiral embolus were noted. 相似文献
103.
D N Fairbanks 《American family physician》1986,33(2):205-211
Snoring means obstructive breathing during sleep, and its most exaggerated form is obstructive sleep apnea. Mild snoring may respond to simple self-help remedies. Heavy snoring responds well to the surgical removal or reconstruction of obstructive elements in the hypopharynx, nasopharynx or nasal passages. 相似文献
104.
K Mahmood M N Chowdhury E A Ayoola I A Mofleh R S Rashed F Z Faleh 《Tropical gastroenterology》1991,12(4):188-191
Seventy seven antral biopsies were collected from patients attending endoscopy clinic at King Khalid University Hospital, Riyadh, Saudi Arabia during a period of six months between December 1988 to May 1989. Of these 69 (89.6%) showed chronic gastritis as well as Helicobacter-like organisms (HLOs) in the biopsy specimens while 63 (81.8%) of biopsies grew Helicobacter pylori on culture. These findings indicate a good correlation between the histological diagnosis of chronic gastritis and isolation of H. pylori on culture. 相似文献
105.
The authors suggest additional criteria evidencing inflammations in the gallbladder and colloid stability of the bile: bile acid absorption and cholesterol sedimentation coefficients. Derivation of these coefficients is based on biochemical examination of the bile with measurements of bile acid, cholesterol, and bilirubin concentrations in both portions. The results of examinations of 99 subjects evidence the diagnostic value and specificity of the characteristics, and availability of this method for clinical practice. 相似文献
106.
A number of children who are admitted for inpatient psychiatric treatment have experienced significant trauma and abuse. It is important to evaluate them for the presence of a DD. The variety, complexity, and subtlety of the symptomatic presentation of childhood MPD makes differential diagnosis difficult, and it is probable that many cases have been missed in the past. Detailed historical information and extensive behavioral observations in a variety of settings can assist in establishing the diagnosis and in delineating areas for therapeutic intervention. Hospitalization may be necessary to conduct an adequate evaluation, develop a therapeutic alliance, safely manage behaviors that are injurious to the child or others, and/or to diffuse potentially volatile family situations. All members of a multidisciplinary inpatient team play important roles in the achievement of successful therapeutic intervention with dissociating children and their families. Skilled family therapy is often an important adjunct to therapeutic interventions focused on the child, particularly when the parent also has MPD. Knowledge of the psychodynamic issues involved in dissociation can be used to develop behavioral interventions that are successful in decreasing the child's need to dissociate, improving his or her overall functioning, and help him or her gain mastery over problematic behaviors. 相似文献
107.
Basic fibroblast growth factor prevents thalamic degeneration after cortical infarction 总被引:10,自引:0,他引:10
K Yamada A Kinoshita E Kohmura T Sakaguchi J Taguchi K Kataoka T Hayakawa 《Journal of cerebral blood flow and metabolism》1991,11(3):472-478
In the focal infarction model of the rat middle cerebral artery (MCA), the thalamus of the occluded side becomes gradually atrophic, mainly because of retrograde degeneration. We determined whether basic fibroblast growth factor (bFGF) administered intracisternally could prevent this thalamic atrophy. We occluded the left MCA through a small cranial opening, and animals were then divided into two groups. One group received intracisternal injections of recombinant bFGF (1 microgram dissolved in 0.1 ml of saline with 2% rat serum) starting 1 day after occlusion and repeated once a week to a total dose of 4 micrograms by four injections. The other group received vehicle solution by the same schedule. The animals were perfused and fixed at 28 days after occlusion, and histological examination was made at the level of the caudoputamen and thalamus. In the bFGF-treated rats, the area of the posterior ventral thalamus of the occluded side was 93% of that of the contralateral side, i.e., significantly larger than in the normal saline-treated rats (75%, p less than 0.01). The infarction size was not statistically different in the two groups. Microscopic observation indicated that normal-saline-treated animals showed shrinkage and disappearance of thalamic neurons, whereas bFGF-treated groups showed preservation of thalamic neurons. Computerized analysis of the cell size substantiated this observation. To assess the effect of bFGF on astrocytes, bFGF or vehicle solution was injected into normal rats, and their histology was evaluated at 1, 2, and 4 weeks after injection. The bFGF-injected group showed a significant increase in glial fibrillary acidic protein-positive astrocytes in the brain tissue facing the ventriculocisternal system.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
108.
The Partial Report Span of Apprehension test has been found to detect cognitive deficits in some first degree relatives of schizophrenic patients. To assess the relative contribution of genetic vs. environmental factors on this measure, 19 monozygotic and 14 dizygotic female twin pairs, selected from a normal population, were tested on the Span of Apprehension test and an IQ test. Both Span of Apprehension test performance and IQ score had high heritabilities: 0.65 and 0.71, respectively. The mode of transmission for performance on the Span of Apprehension test appears to operate in a nonadditive manner. A multivariate behavioral-genetic model applied to the Span of Apprehension and IQ measures indicated that slightly less than half of the genetic effects important for the Span of Apprehension test are found in common with the genetic factors important for IQ. The phenotypic correlation between the Span of Apprehension and IQ measures can be attributed entirely to genetic factors. The influence of unique genetic components in the performance of the Span of Apprehension test in the general population heightens the promise of this measure as a genetic marker for schizophrenia. 相似文献
109.
Oncologic screenings of the populations in the areas with increased incidence of esophageal cancer have revealed Barrett's ulcer in 1 percent of the examinees. Endoscopic and cytologic characteristics of this condition are presented. Precancer changes--severe dysplasia--are most frequent in male Kazakhs (14.1 percent) aged 50 to 59 (14.7 percent). Subjects with Barrett's ulcer developing severe dysplasia, as evidenced by cytograms, should be included in the group of subjects at risk for carcinoma of the lower third of the esophagus and cardia. 相似文献
110.
In the period 1979-1980 the following anthropometric measurements were recorded in 2351 healthy Dutch children from 0-17 years of age: height, weight, sitting height, arm span, lengths of upper-arm, lower-arm and hand, tibial length, foot length, biacromial diameter, biiliacal diameter, and head circumference. Corresponding percentile values were constructed on the basis of normality assumptions, the mean and standard deviation at age t being determined by a cubic spline approximation. The results are compared with other studies and given in the form of growth charts. 相似文献