全文获取类型
收费全文 | 258839篇 |
免费 | 21524篇 |
国内免费 | 12635篇 |
专业分类
耳鼻咽喉 | 3566篇 |
儿科学 | 4309篇 |
妇产科学 | 3204篇 |
基础医学 | 39893篇 |
口腔科学 | 6582篇 |
临床医学 | 20288篇 |
内科学 | 37361篇 |
皮肤病学 | 4880篇 |
神经病学 | 9777篇 |
特种医学 | 7643篇 |
外国民族医学 | 216篇 |
外科学 | 26951篇 |
综合类 | 42244篇 |
现状与发展 | 64篇 |
预防医学 | 6941篇 |
眼科学 | 3780篇 |
药学 | 17814篇 |
96篇 | |
中国医学 | 6997篇 |
肿瘤学 | 50392篇 |
出版年
2025年 | 152篇 |
2024年 | 3261篇 |
2023年 | 4616篇 |
2022年 | 7150篇 |
2021年 | 9762篇 |
2020年 | 8776篇 |
2019年 | 8308篇 |
2018年 | 7957篇 |
2017年 | 8538篇 |
2016年 | 9098篇 |
2015年 | 10407篇 |
2014年 | 15465篇 |
2013年 | 15857篇 |
2012年 | 14514篇 |
2011年 | 15966篇 |
2010年 | 13174篇 |
2009年 | 12736篇 |
2008年 | 13455篇 |
2007年 | 13943篇 |
2006年 | 12756篇 |
2005年 | 11531篇 |
2004年 | 9740篇 |
2003年 | 8460篇 |
2002年 | 7043篇 |
2001年 | 6375篇 |
2000年 | 5354篇 |
1999年 | 4633篇 |
1998年 | 4306篇 |
1997年 | 3922篇 |
1996年 | 3550篇 |
1995年 | 3058篇 |
1994年 | 2701篇 |
1993年 | 2155篇 |
1992年 | 1786篇 |
1991年 | 1662篇 |
1990年 | 1314篇 |
1989年 | 1210篇 |
1988年 | 1106篇 |
1987年 | 896篇 |
1986年 | 805篇 |
1985年 | 1032篇 |
1984年 | 879篇 |
1983年 | 623篇 |
1982年 | 679篇 |
1981年 | 551篇 |
1980年 | 485篇 |
1979年 | 387篇 |
1978年 | 264篇 |
1977年 | 198篇 |
1976年 | 160篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
T. Eiwegger N. Rigby L. Mondoulet H. Bernard M.-T. Krauth A. Boehm E. Dehlink P. Valent J. M. Wal E. N. C. Mills Z. Szépfalusi 《Clinical and experimental allergy》2006,36(10):1281-1288
BACKGROUND: The process of gastro-duodenal digestion may play a role in determining the allergenic properties of food proteins. The sensitizing and allergenic potential of digestion products of highly degraded allergens, such as the major peanut allergen Ara h 1, is currently under debate. We evaluated the effect of in vitro gastro-duodenal digestion of Ara h 1 on T cell reactivity and basophil histamine release. METHODS: An in vitro model of gastro-duodenal digestion was used to investigate changes in the allergenic properties of Ara h 1 using in vitro assays monitoring T cell reactivity (proliferation, cytokine production) and histamine release of basophils from peanut allergic individuals. The digestion process was monitored using an SDS-PAGE gel. RESULTS: In vitro gastric digestion led to rapid degradation of Ara h 1 into small fragments M(r) L5600. Gastric digestion did not affect the ability of Ara h 1 to stimulate cellular proliferation. Gastro-duodenal digestion significantly reduced its ability to stimulate clonal expansion (P<0,05; Wilxocon's signed rank test). The Th-2 type cytokine polarization of T cells from peanut allergic donors (IFN-gamma/IL-13 ratio and IFN-gamma/IL-4 ratio of CFSE(low) CD4(+) T cells) remained unchanged regardless of the level of digestion. Histamine release of basophils from peanut allergic individuals was induced to the same extent by native Ara h 1 and its digestion products. CONCLUSION: Gastro-duodenal digestion fragments of Ara h 1 retain T cell stimulatory and IgE-binding and cross-linking properties of the intact protein. 相似文献
33.
34.
35.
B Essers† F Nieman† M Prins† N Smeets‡ H Neumann§ 《Journal of the European Academy of Dermatology and Venereology》2007,21(9):1209-1214
BACKGROUND: Basal cell carcinoma (BCC) is a non-melanoma form of skin cancer that is frequently localized within the cervicofacial area. So far, little research is available on how patients perceive their facial aesthetics after surgical treatment for BCC. OBJECTIVES: To analyse (i) if there was a statistically significant improvement over time with regard to the perceived facial aesthetics of surgical patients; (ii) if there was a significant difference between primary and recurrent BCC patients; and (iii) between patients who had Mohs micrographic surgery (MMS) or surgical excision (SE). To assess (iv) which baseline perceptions and/or clinical parameters may predict the evaluation of facial aesthetics at 6 months after surgery. METHODS: Parallel to a clinical trial, a survey was carried out in which patients were asked, by means of a newly developed disease-specific questionnaire, about perceptions with regard to their facial aesthetics before and after surgery. RESULTS: Aesthetic perceptions of all surgical patients improved over time. There was no statistically significant difference on facial aesthetics between the group with a primary or recurrent BCC and patients treated with MMS or SE. Results also showed that the evaluation of postsurgical facial aesthetics can be predicted by both visibility of the tumour and preoperative perceptions. CONCLUSION: It is recommended to administer preoperatively a short questionnaire in which perceptions related to facial aesthetics are included. In doing so, physicians will become more familiar with the aesthetic problems patients might have regarding their afflicted facial site. Ultimately, it may help physicians in deciding whether patients will benefit from additional cosmetic procedures after surgery. 相似文献
36.
Ting-Kai Leung Chien-Jui Cheng Chi-Ming Lee Li-Kuo Shen Hung-Jung Wang Ya-Yen Chen 《中华医学杂志(英文版)》2005,118(17):1493-1496
The current report focuses on two patients of the same age who presented similar appearances on initial anteroposterior chest images. Follow-up images showed superoanterior and superoposterior mediastinal lesions. The first patient with noninvasive cystic thymoma was suspected before surgery, while the pathologic diagnosis was intrathoracic phrenic nerve schwannoma. The second patient was with an asymmetric, dumbbell-shaped paravertebral tumor over T3 and T4 on the left side. The preoperative… 相似文献
37.
Calcifying odontogenic cyst (COC) has shown to be of extensive diversity in its clinical and histopathological features, as well as in its biological behavior. In this report, a rare case is described of ameloblastoma ex COC (dentinogenic ghost cell tumor) and the relevant literature is briefly reviewed. 相似文献
38.
Nobuyuki Oka Teruaki Kawasaki Kotaro Mizutani Hiroshi Sugiyama Ichiro Akiguchi 《Neuropathology》2007,27(6):509-515
Neuromuscular biopsy is still an essential method for diagnosing vasculitic neuropathy, although its diagnostic sensitivity is at most 60%. Our objective was to examine the expression of hypoxia‐inducible factor 1α (HIF‐1α) in peripheral nerves and to evaluate its usefulness in diagnosing vasculitic neuropathy, especially for discrimination from other axonal neuropathies. Forty‐one patients with vasculitic neuropathy consisting of 20 definite, 14 probable and seven possible diagnoses, 15 patients with metabolic neuropathy, five with motor neuron disease and six with chronic inflammatory demyelinating polyneuropathy were included. Nerve biopsy specimens were immunohistochemically examined for HIF‐1α and various cell markers. Distinct immunoreactivity (IR) was observed in nuclei of endoneurial cells in 54% (22/41) of vasculitic patients, while specimens from metabolic neuropathies showed less nuclear IR and the difference of mean density of HIF‐1α‐positive nuclei was significant. Two patients with possible vasculitis who showed HIF‐1α‐positive nuclei in endoneurium, were later confirmed to have vasculitis by skin biopsies. Most of the cells expressing HIF were demonstrated to be Schwann cells. There was a trend in the vasculitic patients with early phase nerve damage to display higher endoneurial HIF‐1α‐IR. HIF‐1α may be an immunohistochemical marker for vasculitic neuropathy, especially when the observed section contains no vasculitic lesions. 相似文献
39.
J. R. Alonso R. Arèvalo J. G. Briñòn J. Lara E. Weruaga J. Aijòn 《Anatomy and embryology》1992,185(4):355-361
Summary The distribution of parvalbumin-(PV) immunopositive cell bodies and fibres in the cerebellum of two species of freshwater teleosts (Salmo gairdneri and Barbus meridonalis) was studied using a monoclonal antibody and the avidin-biotin immunoperoxidase technique. A clear laminated pattern of PV immunoreactivity was observed. After PV-immunostaining, Purkinje cells were strongly labelled in their cell bodies, the initial segments of the axons and the dendritic trees. In the molecular layer, only the dendritic branches of the Purkinje cells were PV-positive. In the granule cell layer, extensive axonal plexuses and scattered cell bodies were observed. Most of the immunopositive perikarya were unequivocally identified as displaced Purkinje cells, whereas a reduced number of smaller neurons with unstained dendrites was also found. Eurydendroid cells, the efferent neurons of the teleost cerebellum, were negative; however, they were impinged upon by numerous PV-positive boutons, corresponding to terminals of Purkinje cell axons. Parallel fibres and climbing fibres, as well as stellate cells and granule cells were negative. Basket cells (or deep stellate cells) whose existence in the teleost cerebellum is discussed, were also not observed. The immunoreactivity distribution pattern for PV in the teleost cerebellum differs from previous observations on the localization of this protein in the cerebellum of amniotes. 相似文献
40.
Expression of β-catenin was investigated in normal breast tissue and 66 breast carcinomas in conjunction with expression of epithelial cadherin (E-CD) and α-catenin. In normal mammary ducts and acini, intense β-catenin immunoreactivity was present at the basolateral surfaces of luminal epithelium and weak immunoreactivity was observed at the lateral borders of myoepithelial cells. No β-catenin was revealed at the myoepithelial basal surface. The intercellular expression of β-catenin, as well as of E-CD and α-catenin, was also observed in carcinoma tissues with varying staining intensity. Almost all of 10 intraductal carcinomas and approximately 70% of 41 invasive ductal carcinomas expressed the three molecules at the same level as in normal glands, whereas approximately 80% of 13 invasive lobular carcinomas showed severe deficiency of them. Two lobular carcinomas in situ showed complete absence of all of the proteins. Some of these findings were confirmed biochemically by immunoblotting analysis. In invasive ductal carcinomas, α-catenin was reduced more frequently in diffuse than in solid type tumours, whereas the level of expression of β-catenin and E-CD was unchanged between them. No correlation was present between reduced expression of the adhesion molecules and lymph node metastasis. 相似文献