全文获取类型
收费全文 | 6809篇 |
免费 | 401篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 113篇 |
妇产科学 | 97篇 |
基础医学 | 858篇 |
口腔科学 | 193篇 |
临床医学 | 470篇 |
内科学 | 2049篇 |
皮肤病学 | 107篇 |
神经病学 | 473篇 |
特种医学 | 274篇 |
外科学 | 1154篇 |
综合类 | 28篇 |
预防医学 | 153篇 |
眼科学 | 136篇 |
药学 | 401篇 |
中国医学 | 12篇 |
肿瘤学 | 713篇 |
出版年
2023年 | 40篇 |
2022年 | 84篇 |
2021年 | 144篇 |
2020年 | 85篇 |
2019年 | 126篇 |
2018年 | 151篇 |
2017年 | 112篇 |
2016年 | 165篇 |
2015年 | 161篇 |
2014年 | 206篇 |
2013年 | 245篇 |
2012年 | 344篇 |
2011年 | 405篇 |
2010年 | 241篇 |
2009年 | 185篇 |
2008年 | 399篇 |
2007年 | 379篇 |
2006年 | 403篇 |
2005年 | 417篇 |
2004年 | 400篇 |
2003年 | 365篇 |
2002年 | 383篇 |
2001年 | 143篇 |
2000年 | 154篇 |
1999年 | 134篇 |
1998年 | 106篇 |
1997年 | 73篇 |
1996年 | 88篇 |
1995年 | 45篇 |
1994年 | 73篇 |
1993年 | 65篇 |
1992年 | 106篇 |
1991年 | 106篇 |
1990年 | 71篇 |
1989年 | 82篇 |
1988年 | 65篇 |
1987年 | 61篇 |
1986年 | 59篇 |
1985年 | 66篇 |
1984年 | 35篇 |
1983年 | 37篇 |
1982年 | 18篇 |
1981年 | 11篇 |
1979年 | 26篇 |
1978年 | 24篇 |
1977年 | 24篇 |
1972年 | 10篇 |
1969年 | 19篇 |
1968年 | 21篇 |
1966年 | 10篇 |
排序方式: 共有7246条查询结果,搜索用时 15 毫秒
1.
2.
3.
Shuichi Kuniyuki 《The Journal of dermatology》1997,24(2):120-124
A 50-year-old Japanese man had a blue-black patch on the dorsum of his right wrist. Light and electron microscopic study of the lesion revealed dermal melanocytes containing mature melanosomes, predominantly in the upper dermis. This case was diagnosed as acquired dermal melanocytosis confined to the right wrist. 相似文献
4.
5.
M H Pietraszek S Takahashi Y Takada K Ohara H Inatomi N Kondo K Ohara A Takada 《Thrombosis research》1991,64(2):243-252
Diurnal changes of serotonin-related factors in whole blood and fibrinolytic activity were determined in depressed patients and healthy controls. Whole blood serotonin concentration of depressed patients showed marked changes throughout daytime, with maximum values in the evening and lowest values in the morning, whereas its metabolite 5-HIAA followed a contrary pattern. The circadian rhythm of 5-HT and 5-HIAA in the control group was quite different from depressed patients. Plasma levels of tPA decreased from 12:30 to 16:30. Concentrations of free plasminogen activator inhibitor (PAI-1) and complex of tPA-PAI-1 decreased from 8:30 to 16:30. Plasma levels of total PAI-1 decreased from 8:30 to 16:30. Plasma levels of the fibrinolytic parameters may be lower in depressive patients than in normal controls. These results support the changes in the circadian rhythm of serotonin and its related substances in the blood of depressive patients. 相似文献
6.
We investigated the effects of imaging and display conditions on the detectability of low-contrast objects in digital subtraction angiographic (DSA) images. The test images were produced by superimposition of low-contrast objects on a uniform noisy background obtained with a DSA system. We employed 18-alternative forced-choice (18-AFC) experiments and predictions based on statistical decision theory to study the dependence of the threshold contrasts of the test objects on the object size, incident x-ray exposure, display window width, and display medium. The results indicated that the threshold contrast decreased with increasing object size, and that the detectability of an object of a given size increased with increasing incident x-ray exposure and decreasing width of the display window. We found that the signal-to-noise ratio (SNR) obtained from the perceived statistical decision theory model, which includes the observer's internal noise, can accurately predict the detectability of low-contrast objects in DSA images. The threshold SNR corresponding to 50% correct detection in the 18-AFC experiments had a constant value of 3.8, in agreement with results reported previously for screen-film systems. The theoretical model will be useful for prediction of the performance of a DSA system based on its physical characteristics, and for evaluation of the tradeoff between patient exposure and diagnostic accuracy for a given DSA unit. 相似文献
7.
We report an 80-year-old Japanese male with four primary malignant tumors: malignant melanoma, prostatic cancer, malignant lymphoma, and renal cell carcinoma, which occurred in that respective order. The combination of malignant melanoma and malignant lymphoma is rare. The patient was treated with BCG after an operation for malignant melanoma. He was also treated with cobalt 60 irradiation after an operation for prostatic cancer. We also discuss other reports of multiple malignant tumors and suggest some possible causes of this patient's primary malignant tumors. 相似文献
8.
Shuichi Sato Fumiko Nasu Katsutoshi Motegi 《Journal of oral and maxillofacial surgery》2002,60(8):867-872
PURPOSE: The purpose of this study was to examine changes of chewing movement and masticatory efficiency during the natural course of nonreducing disc displacement of the temporomandibular joint (TMJ). PATIENTS AND METHODS: The subjects were 15 patients who had been diagnosed with nonreducing disc displacement of the TMJ but had received no treatment. Chewing movement and masticatory efficiency were examined at the initial visit and at a mean follow-up of 21.7 months, using mandibular kinesiography and adenosine triphosphate ebteric-coated granules. As a control, 23 persons who had no current or previous TMJ symptoms were studied. RESULTS: The patients' clinical signs and symptoms tended to be alleviated during the follow-up period. In normal controls, chewing movement showed lateral excursion to the chewing side on both the right and left sides. In patients, chewing movement at the initial visit showed lateral excursion to the chewing side during chewing on the TMJ affected side, but no such deviation was noted during chewing on the TMJ unaffected side in the horizontal plane. However, chewing movement at follow-up became similar to that of controls. In patients, masticatory efficiency became better during the natural course, although that at follow-up did not always reach the control's level. CONCLUSION: In untreated patients with nonreducing disc displacement of the TMJ, chewing movement and masticatory efficiency tend to improve spontaneously. 相似文献
9.
Hiromitsu Nakaya Shuichi Kawashiri Akira Tanaka Natsuyo Noguchi Koroku Kato Takashi Hase Etsuhide Yamamoto 《Journal of oral pathology & medicine》2005,34(2):87-92
BACKGROUND: Although it is clear that dissemination via the blood system involves angiogenesis, it is uncertain whether tumors also induce lymphangiogenesis or simply invade existing peritumoral vessels. The purpose of this study was to elucidate changes in tumor blood and lymph vessels in cases involving the invasion of squamous cell carcinoma in the oral cavity, and its significance. Blood and lymph vessels densities in tongue carcinomas induced in hamsters were investigated. METHODS: Tongue cancer was induced by abrading the right margin of the tongue of each hamster with an endodontic barbed broach and subsequently applying 1.0% 9,10-dimenthl-1,2-benzanthracene (DMBA) dissolved in acetone, three times a week, at the same site. Fresh frozen sections were prepared and blood vessels stained blue by perfusion with Coomassie Brilliant Blue and lymph vessels stained brown for 5'-nucleotidase. The effects on the blood vessels and lymph vessels were observed. RESULTS: The results showed that blood and lymph vessel densities were greater in the advanced carcinoma tissues than in normal tissue. These were compared in terms of the mode of cancer invasion. As tumor invasion progressed, the blood vessel density decreased but lymph vessel density tended to be higher in high-degree tumor invasion than in low-degree tumor invasion. The expression of vascular endothelial growth factor-C was seen more frequently as tumor invasion progressed. CONCLUSIONS: The present findings indicated that angiogenesis and lymphangiogenesis are affected by cancerous invasion. 相似文献
10.