全文获取类型
收费全文 | 224995篇 |
免费 | 6159篇 |
国内免费 | 489篇 |
专业分类
耳鼻咽喉 | 3040篇 |
儿科学 | 8553篇 |
妇产科学 | 6782篇 |
基础医学 | 29056篇 |
口腔科学 | 6147篇 |
临床医学 | 19281篇 |
内科学 | 40305篇 |
皮肤病学 | 4935篇 |
神经病学 | 14896篇 |
特种医学 | 11139篇 |
外国民族医学 | 101篇 |
外科学 | 31765篇 |
综合类 | 1405篇 |
一般理论 | 46篇 |
预防医学 | 20722篇 |
眼科学 | 4763篇 |
药学 | 15523篇 |
2篇 | |
中国医学 | 162篇 |
肿瘤学 | 13020篇 |
出版年
2021年 | 1193篇 |
2019年 | 1086篇 |
2018年 | 4589篇 |
2017年 | 4649篇 |
2016年 | 4058篇 |
2015年 | 5760篇 |
2014年 | 5503篇 |
2013年 | 5120篇 |
2012年 | 12329篇 |
2011年 | 7430篇 |
2010年 | 3608篇 |
2009年 | 5032篇 |
2008年 | 4254篇 |
2007年 | 4971篇 |
2006年 | 5024篇 |
2005年 | 12970篇 |
2004年 | 14262篇 |
2003年 | 9634篇 |
2002年 | 4905篇 |
2001年 | 4505篇 |
2000年 | 1828篇 |
1999年 | 6005篇 |
1998年 | 805篇 |
1992年 | 6920篇 |
1991年 | 7135篇 |
1990年 | 7383篇 |
1989年 | 6976篇 |
1988年 | 6501篇 |
1987年 | 6262篇 |
1986年 | 5983篇 |
1985年 | 5251篇 |
1984年 | 3607篇 |
1983年 | 2938篇 |
1982年 | 1023篇 |
1980年 | 846篇 |
1979年 | 3828篇 |
1978年 | 2366篇 |
1977年 | 1785篇 |
1976年 | 1562篇 |
1975年 | 2474篇 |
1974年 | 3108篇 |
1973年 | 2742篇 |
1972年 | 2759篇 |
1971年 | 2744篇 |
1970年 | 2557篇 |
1969年 | 2465篇 |
1968年 | 2238篇 |
1967年 | 2165篇 |
1966年 | 1899篇 |
1965年 | 1133篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
962.
963.
W Kostowski E Malatyńska A P?a?nik W Dyr W Danysz 《Polish journal of pharmacology and pharmacy》1986,38(5-6):471-481
Alprazolam, a new benzodiazepine from triazolobenzodiazepine group, produced anxiolytic action in the conflict test with potency similar to that of diazepam. The myorelaxant activity of the drug was relatively weak. Unlike desipramine, alprazolam failed to reduce the immobility of rats in the forced swim test and was unable to prevent clonidine-induced hypothermia. Alprazolam, unlike desipramine, failed also to potentiate behavioral effect of noradrenaline injected into the hippocampus. Alprazolam after acute but not chronic administration antagonized the synchronizing effect of clonidine on EEG pattern. On the other hand, alprazolam similarly to tricyclic antidepressants, prevented the suppression of dominance behavior by clonidine in rats competing for food. The results indicate that alprazolam acts only weakly upon noradrenergic mechanisms related to depression and to antidepressant action of drugs. 相似文献
964.
Carlos Heitor Cunha Moreira Fabricio Batistin Zanatta Raquel Antoniazzi Priscila Ceolin Meneguetti Cassiano Kuchenbecker R?sing 《Journal of applied oral science : revista FOB》2007,15(5):437-441
When dealing with patients with periodontal disease of variable severities, dentists must often choose between treating and restoring the involved tooth or indicating its extraction. Different criteria have been adopted in this decision-making process. The purpose of this study was to evaluate the criteria adopted by dentists to indicate the extraction of teeth with periodontitis. Dentists were interviewed at their private practices in three cities of the state of Rio Grande do Sul, Brazil. The evaluated criteria included severity of attachment loss, tooth mobility, furcation involvement, prosthetic planning, periodontal-endodontic lesion, possible systemic involvement due to the presence of periodontitis, referral to a periodontist for evaluation, radiographic bone loss greater than 50%, presence of extensive caries, socio-economic and cultural status of the patient, among others. The most often adopted criteria to indicate the extraction of periodontally affected teeth were the presence of mobility (37.5%), severity of attachment loss (24.3%) and radiographic bone loss greater than 50% (21.2%). The results of the present study demonstrated the difficulties faced by dentists to indicate the extraction of teeth with severe attachment loss, in addition to the establishment of an adequate prognosis. Aspects associated with the past disease were still the most often reported to indicate the extraction of teeth for periodontal reasons. 相似文献
965.
Hypertension is a well known risk factor of coronary artery disease. The aim of the study was to evaluate a clinical course and prognosis in hypertensive patients with acute myocardial infarction (MI). 100 consecutive patients with acute MI underwent the study. In 38 of them (28 males and 10 females) a history of hypertension and intermittent rises of arterial blood pressure in a course of MI were stated. All patients underwent 2-DE examination and 24 hours Holter ecg monitoring. Clinical characteristics consisted of the heart failure and arrhythmias occurrence as well as the in-hospital mortality. Significantly higher rate of MI in the past and/or angina pectoris as well as a diabetes mellitus was stated in hypertensive patients. In these patients inferior, transmural MI was more often observed, while there was no difference in life-threatening arrhythmias, pulmonary edema and cardiogenic shock between normotensive and hypertensive patients. 相似文献
966.
Consideration is given to the technique and the device for detecting water amount linked to high-molecular compounds presenting the base for blood substitutes. The device is simple in use, outputs reproducible data comparable to the well known results (e.g. for polyglucine). It should be recommended for evaluating hemodynamic parameters of newly developed blood substitutes. 相似文献
967.
F B?umer 《Zentralblatt für Chirurgie》1987,112(8):485-490
A retrospective study was conducted into 136 patients who had received surgical treatment for perforated gastroduodenal ulcers, with the view to establishing postoperative lethality and morbidity (comparing simple suturing with definitive ulcer surgery). Factors of relevance to prognosis were taken into consideration, including age of patients, number of concomitant diseases, time from perforation to surgery, presence of peritonitis, ulcer location, and length of ulcer history. 相似文献
968.
Matthias Feichtinger Reingard Maria Aigner Gert Santler Hans K?rcher 《Journal of cranio-maxillo-facial surgery》2007,35(6-7):322-328
INTRODUCTION: Surgery based on computed tomography (CT) data is becoming increasingly important in the head and neck region. The technique for hardware fusion between positron emission tomography (PET) and computed tomography (CT) has only been established commercially in the last 4 years. The advantages over CT alone are obvious. The surgeon is simultaneously provided with a map of anatomical as well as of functional (metabolic) details. The fused images offer improved localization of malignant lesions and improved targeting of biopsy, especially for small lesions. PURPOSE: A new technique for image-guided tumour localization for maxillofacial surgery based on PET/CT-image fusion is described. PATIENT AND METHOD: A 78-year-old woman was admitted to this department with a tumour of the skull base. Three dimensional fusion of computed CT with positron PET images on a commercially available navigation system is described. After patient-to-image registration, a high-resolution endoscope was calibrated intraoperatively. Image-guided biopsy specimens were taken under direct visual control. CONCLUSION: PET/CT-image fusion proved extremely helpful to navigate the endoscope to the target lesion and to identify the tumour. 相似文献
969.
With regard to disturbances of the iron metabolism, porphyria cutanea tarda (PCT) is most frequently accompanied by liver siderosis. In 74 out of 88 patients suffering from PCT (84%), we found histochemical evidence of liver siderosis. These patients showed a significantly higher incidence of HLA A3--which has been proved to be associated with hemochromatosis--than those without liver siderosis (39.2% vs. 7.1%). With part of the PCT patients, disorders of the iron metabolism related to the HLA system (A3) might contribute to the manifestation of the disease. We discuss PCT as the result of the combined action of several predisposing genetic markers and exogenic factors. 相似文献
970.