全文获取类型
收费全文 | 2562310篇 |
免费 | 183423篇 |
国内免费 | 3799篇 |
专业分类
耳鼻咽喉 | 35265篇 |
儿科学 | 83501篇 |
妇产科学 | 70046篇 |
基础医学 | 377938篇 |
口腔科学 | 69358篇 |
临床医学 | 230212篇 |
内科学 | 495982篇 |
皮肤病学 | 56382篇 |
神经病学 | 201635篇 |
特种医学 | 96359篇 |
外国民族医学 | 526篇 |
外科学 | 385955篇 |
综合类 | 53029篇 |
现状与发展 | 13篇 |
一般理论 | 989篇 |
预防医学 | 198509篇 |
眼科学 | 59548篇 |
药学 | 189840篇 |
40篇 | |
中国医学 | 5067篇 |
肿瘤学 | 139338篇 |
出版年
2021年 | 21160篇 |
2019年 | 21630篇 |
2018年 | 30211篇 |
2017年 | 22590篇 |
2016年 | 25403篇 |
2015年 | 28818篇 |
2014年 | 40076篇 |
2013年 | 60218篇 |
2012年 | 82046篇 |
2011年 | 86664篇 |
2010年 | 52066篇 |
2009年 | 49053篇 |
2008年 | 81190篇 |
2007年 | 86536篇 |
2006年 | 87243篇 |
2005年 | 84351篇 |
2004年 | 80753篇 |
2003年 | 77664篇 |
2002年 | 75012篇 |
2001年 | 116322篇 |
2000年 | 119191篇 |
1999年 | 100214篇 |
1998年 | 29061篇 |
1997年 | 25516篇 |
1996年 | 25816篇 |
1995年 | 24352篇 |
1994年 | 22453篇 |
1993年 | 21135篇 |
1992年 | 77015篇 |
1991年 | 75221篇 |
1990年 | 73476篇 |
1989年 | 70742篇 |
1988年 | 64901篇 |
1987年 | 63724篇 |
1986年 | 59607篇 |
1985年 | 57311篇 |
1984年 | 42444篇 |
1983年 | 36138篇 |
1982年 | 21585篇 |
1979年 | 38907篇 |
1978年 | 27843篇 |
1977年 | 23133篇 |
1976年 | 22104篇 |
1975年 | 23856篇 |
1974年 | 28587篇 |
1973年 | 27267篇 |
1972年 | 25531篇 |
1971年 | 24244篇 |
1970年 | 22396篇 |
1969年 | 21216篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
The use of computer technology for patient education has increased in recent years. This article describes a study that measures the attitudes and perceptions of healthcare professionals and laypeople regarding the effectiveness of a multimedia computer, the Brain Injury Resource Center? (BIRC), as an educational tool. The study focused on three major themes: (a) usefulness of the information presented, (b) effectiveness of the multimedia touch-screen computer methodology, and (c) the appropriate time for making this resource available. This prospective study, conducted in an acute care medical center, obtained healthcare professionals' evaluations using a written survey and responses from patients with brain injury and their families during interviews. The findings have yielded excellent ratings as to the ease of understanding and usefulness of the BIRC. By using sight, sound, and touch, such a multimedia learning center has the potential to simplify patient and family education. 相似文献
142.
A. HAZIOT I. KATZ G. W. RONG X. Y. LIN J. SILVER & S. M. GOYERT 《Scandinavian journal of immunology》1997,46(3):242-245
Membrane-bound CD14 acts as a receptor for lipopolysaccharide (LPS) on monocytes/macrophages and neutrophils. Studies have suggested that the activation of monocytes/macrophages by the binding of LPS to membrane-bound CD14 may require the association of a signal-transducing molecule with membrane-bound CD14. The observation that non-CD14 expressing cells, such as endothelial cells, can nevertheless be activated by a complex of LPS and a soluble form of CD14 (sCD14) suggests that the receptor for this complex may be identical to the signal transducing molecule associated with membrane-bound CD14. The studies described show that two CD14-specific MoAb are able to block the LPS-induced activation of endothelial cells but do not affect the response of monocytes to LPS. This suggests that the interaction of the sCD14:LPS complex with endothelial cells is distinct from the interaction of membrane-bound CD14 with its putative signal-transducing molecule. 相似文献
143.
144.
145.
Palytoxin, a highly toxic natural product isolated from zoanthids of the genus Palythoa, is accumulated by a wide range of fishes and marine invertebrates used as food in the Indo-Pacific. It is responsible for many incidents of human morbidity and mortality. The toxin is a potent smooth muscle spasmogen. The cause of the contraction of smooth muscle is unclear, but recent work strongly suggests that it is primarily initiated by the release of neurotransmitters from the motor innervation of the smooth muscle. We show here that palytoxin caused the swelling of the muscle cells and some internal organelles of the anococcygeus muscle of the rat, but no substantial structural damage to the tissue. Axons and Schwann cells were also swollen but the most dramatic feature was the depletion of synaptic vesicles from putative release sites in the axons. Some axons were physically damaged following exposure to the toxin, but this was relatively uncommon (<10% of all axons studied). In the majority of axons there was no damage to nerve terminal membranes, but there was damage to mitochondria. The depletion of vesicles involved all types – clear, dense-cored, large and small. Our observations and pharmacological data gathered elsewhere, provide a neuropathological basis for the spasmogenic activity of palytoxin. 相似文献
146.
The ability of three Porphyromonas spp., seven Prevotella spp., seven Fusobacterium spp. and two related Bacteroides spp. (B. levii and B. macacae) to degrade an extensive range of synthetic endo-, amino- and diamino peptidase substrates linked to the fluorescent leaving group 7-amido-4-methylcoumarin (NHMec) was investigated. Many more species than was previously recognized exhibited peptidase activities, albeit at lower levels than those already described for Porphyromonas gingivalis. Detection of chymotrypsin-like activity was dependent on which of three NHMec-linked substrates was used, but all species exhibited degradative activity with at least one of these substrates. Elastase-like activity was detected in all species though not all species reacted with each of the elastase substrates. Glycylprolyl peptidase activity was detected in all of the species tested with the exception of F. mortiferum, F. gonidiaformans, F. naviforme and F. necrophorum. While the detection of peptidase activities does not appear to be useful for the differentiation of species within the genera Bacteroides and Prevotella, its ability to differentiate species of the genus Porphyromonas or Fosobacterium further investigation. 相似文献
147.
148.
summary The aetiology of denture stomatitis is not clear from the literature. Some studies show its aetiology as Candida albicans, while other reports point out the significance of microorganisms. In this study the existence of C. albicans and microorganisms was investigated in subjects with and without denture stomatitis. The results showed that a combination of C. albicans and microorganisms is more likely to be responsible for denture stomatitis. 相似文献
149.
A. Al Tahan S. Arora A. Alzeer F. Al Tahan T. Malabarey A. Daif 《European journal of neurology》1997,4(1):52-58
The diagnosis of acute disseminated encephalomyelitis (ADEM) is frequently missed or delayed with consequent delay in instituting therapy in the crucial phase of the illness. The role of MRI in the diagnosis of ADEM is well established, however, the value of its early utilization of treatment on the outcome of patients has not been adequately stressed. Three patients with ADEM are described. Delay in the diagnosis of the first was associated with severe sequelae, while in the other two early diagnosis and institution of corticosteroid therapy which was facilitated by MRI, was associated with a better outcome. MRI should be carried out early once the diagosis of ADEM is entertained. 相似文献
150.
The value of ultrasound in the diagnosis of a large rapidly growing thyroid mass was assessed in a study of 42 patients with a large (> 3 cm) rapidly growing (< two months) solitary mass. Haemorrhage into a thyroid nodule was present in 31 patients and thyroid malignancy in 11. Ultrasound of haemorrhage into a thyroid nodule revealed a large cystic mass in all 31 patients containing internal debris (22), septations (three), or a combination of both (six). The malignant causes of a large rapidly growing mass were lymphoma (two), anaplastic carcinoma (four) and metastasis (five). Ultrasound of these thyroid malignancies revealed a mass with a smooth, well-defined margin and strikingly low homogeneous echogenicity in all cases. Patients with thyroid metastases had evidence of widespread metastatic disease elsewhere. Lymphoma was differentiated from anaplastic carcinoma on fine-needle aspiration cytology or surgical biopsy. Ultrasound was of value in differentiating between a benign haemorrhagic nodule and a malignant tumour. The various malignant tumours had similar appearances, however, and could not be distinguished on ultrasound. 相似文献