全文获取类型
收费全文 | 8263篇 |
免费 | 200篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 198篇 |
儿科学 | 731篇 |
妇产科学 | 371篇 |
基础医学 | 736篇 |
口腔科学 | 223篇 |
临床医学 | 675篇 |
内科学 | 1629篇 |
皮肤病学 | 397篇 |
神经病学 | 312篇 |
特种医学 | 179篇 |
外科学 | 1252篇 |
综合类 | 312篇 |
一般理论 | 2篇 |
预防医学 | 721篇 |
眼科学 | 167篇 |
药学 | 420篇 |
1篇 | |
中国医学 | 13篇 |
肿瘤学 | 164篇 |
出版年
2017年 | 45篇 |
2016年 | 33篇 |
2015年 | 62篇 |
2014年 | 60篇 |
2013年 | 98篇 |
2012年 | 110篇 |
2011年 | 127篇 |
2010年 | 115篇 |
2009年 | 151篇 |
2008年 | 82篇 |
2007年 | 83篇 |
2006年 | 106篇 |
2005年 | 64篇 |
2002年 | 28篇 |
2001年 | 44篇 |
2000年 | 27篇 |
1999年 | 66篇 |
1998年 | 152篇 |
1997年 | 185篇 |
1996年 | 205篇 |
1995年 | 161篇 |
1994年 | 159篇 |
1993年 | 157篇 |
1992年 | 93篇 |
1991年 | 101篇 |
1990年 | 99篇 |
1989年 | 106篇 |
1988年 | 88篇 |
1987年 | 101篇 |
1986年 | 83篇 |
1985年 | 62篇 |
1984年 | 62篇 |
1983年 | 52篇 |
1982年 | 50篇 |
1981年 | 57篇 |
1980年 | 42篇 |
1979年 | 33篇 |
1978年 | 30篇 |
1977年 | 44篇 |
1976年 | 37篇 |
1959年 | 343篇 |
1958年 | 759篇 |
1957年 | 868篇 |
1956年 | 771篇 |
1955年 | 803篇 |
1954年 | 780篇 |
1953年 | 40篇 |
1952年 | 35篇 |
1949年 | 182篇 |
1948年 | 125篇 |
排序方式: 共有8503条查询结果,搜索用时 0 毫秒
991.
992.
R. C. DE L. MILTON E. MAYER J.H. WALSH J.E. RIVIER J. DYKERT T.D. LEE J.E. SHIVELY J. R. REEVE 《Chemical biology & drug design》1988,32(2):141-152
Two canine gastrin-releasing peptides originally isolated from gut tissue extracts have been synthesized by solid phase methodology and purified by preparative reverse phase high performance liquid chromatography (RP-HPLC). The synthetic gastrin-releasing peptides GRP1-27 and GRP 5-27 were characterized with regard to homogeneity and composition using nine different RP-HPLC systems, mass spectroscopy, amino acid analysis, Edman degradation, methionine oxidation, and peptide mapping with tryptic, Staph. aureus V8 protease and cyanogen bromide cleavage (the latter two systems performed only with GRP 1-27). Although a scarcity of the natural products prevented quantitative biological comparison of the synthetic and natural peptides, they were found to elute identically on RP-HPLC co-chromatography and similar dose dependent biological potencies were observed in canine antral muscle tissue contraction experiments. Indeed, all the peptides containing the bombesin-like car-boxyl terminal decapeptide sequence studied to date have similar biological activities. 相似文献
993.
summary The purpose of the study was to evaluate the effect of early orthodontic treatment of functional unilateral posterior crossbite (FUPC) and to evaluate temporomandibular function in the short and long term. Orthodontic treatment consisted of slow expansion of the maxillary dental arch by means of a removable expansion plate, with flat coverage of the occlusal surfaces of the left and right posterior teeth. Evaluation of the occlusion showed a strong correlation between the crossbite side and the direction of the RCP-ICP slide and with the side of first occlusal contact in RCP. In 26 of 27 children that were treated (one withdrew), the average time required for correction of the crossbite was 7 months, followed by a retention period, on average, for 6 months after completion of treatment. Early orthodontic treatment resulted in an elimination of occlusal disturbances, and the crossbite remained stable on follow-up during an average of 8 years after the retention period, except in two children with a class III tendency. In nine other children an orthodontic anomaly had developed requiring further treatment (two children showed crowding and seven children showed a class II malocclusion). This study showed that FUPC can be treated adequately by early orthodontic intervention; however, its correction does not guarantee the absence of functional disturbances at a later age. Therefore, FUPC should be treated early in order to achieve normal growth and development rather than to prevent temporomandibular disorders. 相似文献
994.
The DNA content is determined by the cytophotometric method in 16 astroglial tumours, classified according to the degree of clinical malignancy. The values are compared to those found in non-tumoural astrocytes. This method appears to be more reliable in assessment of the degree of malignancy of the tumour in biopsy material than histological criteria and the mitotic index. It is also shown to be of great value in cases where the biopsy is taken at the margin of the tumour and in which malignant histological features are missing. 相似文献
995.
996.
Normal diastolic filling patterns of the left ventricle 总被引:6,自引:0,他引:6
VAN DAM I.; FAST J.; DE BOO T.; HOPMAN J.; VAN OORT A.; HERINGA A.; ALSTERS J.; VAN DER T.; DANIELS O. 《European heart journal》1988,9(2):165-171
Pulsed Doppler measurements on both sides of the mitral valveand M-mode left ventricular echocardiograms were performed in215 healthy subjects, 120 males and 95 females, between oneand 65 years old, in order to evaluate normal diastolic fillingpatterns of the left ventricle. The relation between the maximumblood velocity during early passive filling (Ewave) and duringatrial contraction (A wave) was computed from the Doppler spectraobtained proximal and distal to the mitral valve, resultingin the EA ratio. The influence on the EA ratio of age, gender,body surface area, blood pressure, heart rate, PR interval,respiration, wall thickness and basal wall mass of the leftventricle was investigated. The study showed that the EA ratio measured proximal to themitral valve (in the left atrium) was significantly smallerthan the EA ratio measured distal (in the left ventricle) andthat the only prominent relations with the EA ratio were thosewith age and heart rate. The EA ratio declines with age: proximalto the mitral valve from approximately (medians) 2.5 to 1 anddistal to it from 3.5 to 1.5. All other physiological variablesare weakly related or unrelated to the EA ratio in this groupof healthy subjects. 相似文献
997.
998.
999.
Immunhistochemische Untersuchungen von Hodenbiopsiepräparaten bei Infertilität des Mannes
Bei 50 beidseitig durchgeführten Hodenbiopsien wurden immunhistochemische und morphologische Untersuchungen vorgenommen. Es zeigte sich in 20% der Fälle das Vorhandensein von Immunglobulin (IgG und IgM) in der Lamina propria, in den Keimzellen, in den Leydig-Zellen und in den Gefäßen, woraus abgeleitet wird, daß ein testikuläres Immunphänomen bei der Pathogenese der Infertilität des Mannes eine Rolle spielen dürfte. Einzelne Beobachtungen machen es deutlich, daß die Immunphänomene labil sind und daß ausschließlich eine multidisziplinäre und dynamische Einstellung einigen Fortschritt in die Lösung dieses Problems zu bringen vermag. 相似文献
Bei 50 beidseitig durchgeführten Hodenbiopsien wurden immunhistochemische und morphologische Untersuchungen vorgenommen. Es zeigte sich in 20% der Fälle das Vorhandensein von Immunglobulin (IgG und IgM) in der Lamina propria, in den Keimzellen, in den Leydig-Zellen und in den Gefäßen, woraus abgeleitet wird, daß ein testikuläres Immunphänomen bei der Pathogenese der Infertilität des Mannes eine Rolle spielen dürfte. Einzelne Beobachtungen machen es deutlich, daß die Immunphänomene labil sind und daß ausschließlich eine multidisziplinäre und dynamische Einstellung einigen Fortschritt in die Lösung dieses Problems zu bringen vermag. 相似文献
1000.