全文获取类型
收费全文 | 2635150篇 |
免费 | 209696篇 |
国内免费 | 4904篇 |
专业分类
耳鼻咽喉 | 35849篇 |
儿科学 | 87615篇 |
妇产科学 | 74898篇 |
基础医学 | 374197篇 |
口腔科学 | 75584篇 |
临床医学 | 236418篇 |
内科学 | 515806篇 |
皮肤病学 | 58611篇 |
神经病学 | 216036篇 |
特种医学 | 103122篇 |
外国民族医学 | 897篇 |
外科学 | 395552篇 |
综合类 | 64786篇 |
现状与发展 | 6篇 |
一般理论 | 970篇 |
预防医学 | 207347篇 |
眼科学 | 60898篇 |
药学 | 192594篇 |
3篇 | |
中国医学 | 5477篇 |
肿瘤学 | 143084篇 |
出版年
2018年 | 27439篇 |
2017年 | 21093篇 |
2016年 | 23769篇 |
2015年 | 27024篇 |
2014年 | 37934篇 |
2013年 | 57313篇 |
2012年 | 77460篇 |
2011年 | 81858篇 |
2010年 | 48350篇 |
2009年 | 46205篇 |
2008年 | 76997篇 |
2007年 | 81420篇 |
2006年 | 82667篇 |
2005年 | 80228篇 |
2004年 | 77785篇 |
2003年 | 74392篇 |
2002年 | 72314篇 |
2001年 | 125898篇 |
2000年 | 129511篇 |
1999年 | 108843篇 |
1998年 | 30518篇 |
1997年 | 27622篇 |
1996年 | 27565篇 |
1995年 | 26500篇 |
1994年 | 24516篇 |
1993年 | 23159篇 |
1992年 | 86268篇 |
1991年 | 83157篇 |
1990年 | 80630篇 |
1989年 | 77495篇 |
1988年 | 71816篇 |
1987年 | 70484篇 |
1986年 | 66630篇 |
1985年 | 63902篇 |
1984年 | 48290篇 |
1983年 | 41321篇 |
1982年 | 24724篇 |
1981年 | 22043篇 |
1979年 | 44743篇 |
1978年 | 31270篇 |
1977年 | 26310篇 |
1976年 | 24782篇 |
1975年 | 25742篇 |
1974年 | 31465篇 |
1973年 | 30382篇 |
1972年 | 28061篇 |
1971年 | 26131篇 |
1970年 | 24422篇 |
1969年 | 22752篇 |
1968年 | 21053篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This article describes the outcomes of a study involving family members of communication-impaired long-term care residents in a collaborative nursing/speech language pathology intervention designed to increase the residents' communication ability. Family members provided memorabilia and artifacts or produced audio or video tapes, for use in conjunction with a speech therapy enhancement program (STEP). Findings revealed that, despite a minimal improvement in speech ability, there was a dramatic increase in family members' satisfaction. 相似文献
992.
We have systematically investigated the involvement of endogenous opioids in gonadotropin secretion during primate sexual maturation by examining LH/FSH responses to gonadotropin-releasing hormone (GnRH) and changes in LH secretion during infusions of saline or naloxone, an opiate antagonist, in ten male chimpanzees between one and nine years of age. Animals were anesthetized with ketamine (10 mg/kg) and injected or infused IV with GnRH, naloxone or saline. Circulating levels of serum LH were elevated to the same extent (approximately 400%) in response to GnRH (100 micrograms) in animals 1-5 years old (juvenile) and in animals 6-9 years old (pubertal). No differences were noted between the two groups in GnRH-stimulated levels of serum FSH. During treatment with naloxone (0.14 mg/kg bolus followed by 0.2 mg/kg/h maintenance infusion for 3 h), serum LH levels in pubertal animals were significantly (p less than 0.05) elevated by as much as 95% over LH levels found during treatment with saline. Juvenile animals, on the other hand, failed to demonstrate significant increases in serum LH following naloxone at the doses tested. A strong correlation (r = .84) was found between circulating testosterone and serum LH levels during naloxone treatment. These data indicate that opioid inhibition of LH secretion can be reversed by naloxone only when puberty is reached in chimpanzees and suggest an alteration in opioid regulation of GnRH near the time of puberty. The strong correlation between testosterone levels and LH responses to naloxone suggests that steroids may participate in the maturation of opioid control of LH during puberty of nonhuman primates. 相似文献
993.
994.
Use of sonography to evaluate carotid atherosclerosis in the elderly. The Cardiovascular Health Study. CHS Collaborative Research Group 总被引:10,自引:0,他引:10
D H O'Leary J F Polak S K Wolfson M G Bond W Bommer S Sheth B M Psaty A R Sharrett T A Manolio 《Stroke; a journal of cerebral circulation》1991,22(9):1155-1163
Carotid sonography is being performed on more than 5,000 participants in the Cardiovascular Health Study, a prospective, multicenter study of cardiovascular disease in men and women aged 65 years and older. The sonographic methods used to examine and measure the extracranial carotid arteries are described. Initial validation studies were performed on 61 subjects with a mean age of 68.6 years. Analysis of within- and between-sonographer differences and between-reader differences were performed for selected variables. In general, the mean absolute differences for within- and between-sonographer comparisons were small, with even less variability between readers. Variability was less for the common carotid artery than for the internal carotid artery. These data suggest that carotid sonography is a reliable and reproducible method for use in the study of carotid atherosclerosis in population studies. 相似文献
995.
J H Lipschutz R M Pascuzzi J Bognanno T Putty 《Stroke; a journal of cerebral circulation》1991,22(6):813-815
A 43-year-old woman suffered a blast-type injury to the head and neck. She subsequently developed bilateral internal carotid artery occlusion and bilateral anterior cerebral artery infarction not demonstrated by magnetic resonance imaging scan 24 hours after the explosion, but confirmed by a second scan 8 days after the explosion. In patients with blast-type injury to the head and neck who develop coma with a nonfocal neurological exam, the possibility of bilateral carotid artery occlusion and bilateral ischemic infarction should be considered. 相似文献
996.
The General Practice Research Club was established in 1969, and now has 120 members. A meeting of the club is held twice a year, at which various papers, from research ideas through to completed, published studies are presented. A survey of 40 individuals who had presented papers at meetings during the period 1984-89 showed that almost half (18) had presented papers on clinical topics. As a result of the presentation, 29 individuals had modified their research, with 11 undertaking major alterations. The meeting was rated most highly by those offering ideas and plans for research. Most individuals responded positively to the meetings, commenting that they valued peer review, found the meetings encouraging, and useful for focusing ideas. Lack of criticism and feedback was commented upon. The club has an important role to play in encouraging research by service general practitioners. 相似文献
997.
R S Desowitz K K Shida L Pang G Buchbinder 《The American journal of tropical medicine and hygiene》1989,41(6):630-634
This study characterizes a Plasmodium berghei white rat model of P. falciparum malaria in the pregnant human. Seventy-day-old and 114-day-old female rats, given an infecting inoculum at time of mating, had higher parasitemias and a more severe anemia than age- and sex-matched controls. Under these experimental conditions, the parasitemia went to crisis in all animals and there were no fatal infections. In contrast, all animals died when the infection was initiated 7 days after conception, a timing that brought a coincidence of peak parasitemia and term. Pregnancy during the post-crisis subpatent period did not cause recrudescence. At the time of delivery, the parasitemia was consistently higher in the placental (crush smear) blood than in the peripheral (tail) blood. This difference was greatest in animals giving birth shortly before or 1-2 days after the parasitemic crisis. Very young, compact parasite forms predominated in the placental blood, whereas trophozoites predominated in the peripheral blood. 相似文献
998.
A Girdhar B Mishra R K Lavania A K Bagga G N Malaviya B K Girdhar 《International journal of leprosy and other mycobacterial diseases : official organ of the International Leprosy Association》1989,57(2):472-475
Two infants, one 4 months old and the other 2 months old, having histologically confirmed indeterminate leprosy are reported. The route of infection, mode of transmission, and incubation period are discussed with reference to these two cases of infantile leprosy. 相似文献
999.
1000.
Lithium is a widely prescribed drug used for the treatment of bipolar affective illness. Previous reports on its effects on sperm motility and male fertility are conflicting. The effect of lithium on human sperm motility was examined in vitro using the modified transmembrane migration method. This technique takes account of the dilution of lithium that occurs during the incubation. Lithium inhibits human sperm motility in vitro in concentrations comparable with those reported to be achieved in semen after oral administration. 相似文献