全文获取类型
收费全文 | 890893篇 |
免费 | 73501篇 |
国内免费 | 1860篇 |
专业分类
耳鼻咽喉 | 12971篇 |
儿科学 | 25584篇 |
妇产科学 | 25897篇 |
基础医学 | 128127篇 |
口腔科学 | 26049篇 |
临床医学 | 78950篇 |
内科学 | 169583篇 |
皮肤病学 | 17439篇 |
神经病学 | 72605篇 |
特种医学 | 36374篇 |
外国民族医学 | 173篇 |
外科学 | 139809篇 |
综合类 | 25214篇 |
现状与发展 | 2篇 |
一般理论 | 304篇 |
预防医学 | 70590篇 |
眼科学 | 21285篇 |
药学 | 66786篇 |
中国医学 | 1631篇 |
肿瘤学 | 46881篇 |
出版年
2018年 | 7861篇 |
2015年 | 8191篇 |
2014年 | 11774篇 |
2013年 | 17792篇 |
2012年 | 24120篇 |
2011年 | 25235篇 |
2010年 | 14680篇 |
2009年 | 13794篇 |
2008年 | 23812篇 |
2007年 | 25920篇 |
2006年 | 25832篇 |
2005年 | 25398篇 |
2004年 | 24961篇 |
2003年 | 24020篇 |
2002年 | 23037篇 |
2001年 | 36821篇 |
2000年 | 37455篇 |
1999年 | 31748篇 |
1998年 | 9588篇 |
1997年 | 8868篇 |
1996年 | 8777篇 |
1995年 | 8247篇 |
1994年 | 8001篇 |
1992年 | 27284篇 |
1991年 | 26667篇 |
1990年 | 26208篇 |
1989年 | 25201篇 |
1988年 | 23755篇 |
1987年 | 23353篇 |
1986年 | 22196篇 |
1985年 | 21586篇 |
1984年 | 16803篇 |
1983年 | 14309篇 |
1982年 | 9069篇 |
1981年 | 8418篇 |
1980年 | 7886篇 |
1979年 | 17073篇 |
1978年 | 12369篇 |
1977年 | 10381篇 |
1976年 | 9533篇 |
1975年 | 10335篇 |
1974年 | 12843篇 |
1973年 | 12340篇 |
1972年 | 11731篇 |
1971年 | 10874篇 |
1970年 | 10391篇 |
1969年 | 10078篇 |
1968年 | 9032篇 |
1967年 | 8353篇 |
1966年 | 7751篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
W Lees 《Ultrasound in obstetrics & gynecology》1993,3(3):162-163
An ultrasound contrast agent which survives transit through the pulmonary circulation after injection into a peripheral vein can also be used for the demonstration of flow characteristics in the peripheral organs. Such a substance (SH U 508 A, Schering AG, Berlin) was tested in the Gynecological Department of the University of Marburg for its suitability for enhancing color-coded Doppler signals in mammary diagnosis in a group of ten women with breast tumors. The observations made are compared with the histologically confirmed diagnoses. The very distinct enhancement of the color-coded Doppler signals allows reliable demonstration of the vascularization characteristics, not only of the malignant, but also of all benign solid tumors examined. Color signals were even recorded from normal mammary tissue, which means that the demonstration of perfusion can no longer be used on its own as a diagnostic criterion. Observation of the characteristics of the blood supply to a tumor might, on the other hand, be an advantage, not only in respect of tumor typing, but also as regards the prognosis of a tumor. In this connection, the registration of the arrival, retention and wash-out phases specific to a contrast agent appears to furnish particularly interesting information about the growth dynamics of a tumor. 相似文献
62.
63.
W. Hughes A. Barr B. C. Dow† E. A. C. Follett † J. A. J. Barbara‡ 《Transfusion medicine (Oxford, England)》1995,5(3):225-230
SUMMARY. Samples from 1828 donations were screened for anti-HBc at seven sites in the UK using kits supplied by 10 manufacturers. Only 10 (0.55%) donations were considered to have true anti-HBc reactivity and these were detected by all 10 kits. Additional markers of HBV infection were found in nine of these 10 donations. Additional reactives were found by all kits, the number ranging from 1 to 43.
In the four more specific kits, the 10 true reactives were clearly distinguished from the 'false reactives' by the strength of the reaction. It is concluded that the reliance on a single ELISA test for anti-HBc diagnosis is unwise. The use of a second test known to be more specific than the screening ELISA is recommended. 相似文献
In the four more specific kits, the 10 true reactives were clearly distinguished from the 'false reactives' by the strength of the reaction. It is concluded that the reliance on a single ELISA test for anti-HBc diagnosis is unwise. The use of a second test known to be more specific than the screening ELISA is recommended. 相似文献
64.
65.
PCP and related compounds inhibit 3H-mazindol binding to the cocaine receptor on dopamine transporters. The relative potencies of these compounds are such that some of the behavioral effects of PCP could be related to its action at the cocaine receptor; however, the affinity of PCP at the cocaine site (Ki = 1.59 microM) is less than its affinity at its own receptor (Ki about 0.12 microM). More data will be needed to conclusively implicate the cocaine receptor in the action of PCP. 相似文献
66.
67.
68.
Treatment versus no treatment in chronic open angle glaucoma 总被引:1,自引:0,他引:1
In a controlled randomized study 15 patients (20 eyes) with chronic open angle glaucoma and visual field defects were followed by greater than 1 year, 12 of them were followed for 3 years. Half of the group were untreated controls, the other half treated with pressure reducing medical therapy. At least 5 consecutive computerized visual fields were recorded (COMPETER) on each eye, and the linear regression coefficient was calculated. With the reservation for uncontrolled compliance no significant difference in the line of favourable effect of pressure reduction could be spotted, in spite of an average pressure reduction in the treated group of 4 mmHg. More important than this result, which is open to criticism for the smallness of the material, uncontrolled compliance etc, is the lesson that a randomized experiment with treated and non-treated glaucoma cases carried out in accordance with the Helsingfors convention is hardly feasible. 相似文献
69.
70.
D. Lothschütz M. Jennewein S. Pahl H.F. Lausberg A. Eichler W. Mutschler R.G. Hanselmann M. Oberringer 《Inflammation research》2002,51(8):416-422
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi. 相似文献