全文获取类型
收费全文 | 456770篇 |
免费 | 41497篇 |
国内免费 | 26775篇 |
专业分类
耳鼻咽喉 | 3790篇 |
儿科学 | 6884篇 |
妇产科学 | 5733篇 |
基础医学 | 52174篇 |
口腔科学 | 7889篇 |
临床医学 | 60608篇 |
内科学 | 67396篇 |
皮肤病学 | 5322篇 |
神经病学 | 26033篇 |
特种医学 | 16670篇 |
外国民族医学 | 230篇 |
外科学 | 46200篇 |
综合类 | 72600篇 |
现状与发展 | 87篇 |
一般理论 | 107篇 |
预防医学 | 33758篇 |
眼科学 | 12412篇 |
药学 | 46497篇 |
432篇 | |
中国医学 | 24688篇 |
肿瘤学 | 35532篇 |
出版年
2024年 | 1167篇 |
2023年 | 5717篇 |
2022年 | 14805篇 |
2021年 | 19459篇 |
2020年 | 14964篇 |
2019年 | 12890篇 |
2018年 | 13764篇 |
2017年 | 12827篇 |
2016年 | 12055篇 |
2015年 | 18265篇 |
2014年 | 23141篇 |
2013年 | 22259篇 |
2012年 | 32946篇 |
2011年 | 36786篇 |
2010年 | 24343篇 |
2009年 | 20082篇 |
2008年 | 25813篇 |
2007年 | 25827篇 |
2006年 | 24759篇 |
2005年 | 23776篇 |
2004年 | 17110篇 |
2003年 | 16285篇 |
2002年 | 13876篇 |
2001年 | 11012篇 |
2000年 | 10594篇 |
1999年 | 10486篇 |
1998年 | 6564篇 |
1997年 | 6089篇 |
1996年 | 4823篇 |
1995年 | 4501篇 |
1994年 | 3842篇 |
1993年 | 2664篇 |
1992年 | 3676篇 |
1991年 | 3278篇 |
1990年 | 2797篇 |
1989年 | 2647篇 |
1988年 | 2273篇 |
1987年 | 2049篇 |
1986年 | 1783篇 |
1985年 | 1532篇 |
1984年 | 1185篇 |
1983年 | 955篇 |
1982年 | 828篇 |
1981年 | 803篇 |
1980年 | 717篇 |
1979年 | 587篇 |
1978年 | 447篇 |
1977年 | 418篇 |
1976年 | 334篇 |
1974年 | 360篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Leonora Q. Schwandt Henri-Jacques Tjong-Ayong Ranny van Weissenbruch Henny C. der Mei Frans W. J. Albers 《European archives of oto-rhino-laryngology》2006,263(6):518-523
Tracheoesophageal voice prostheses need to be replaced due to increased airflow resistance or retrograde leakage of fluid into the trachea as a consequence of biofilm formation. Previous in vitro studies show a change of aerodynamic features of biofilm covered voice prostheses after removal of the prostheses out of the patient. To assess these changes in an in situ situation, aerodynamic characteristics were measured within 45 patients at the beginning and at the end of the wearing process of the Provox 2 voice prosthesis. As a consequence, the influence of biofilm formation on aerodynamic characteristics can be evaluated. In the majority of cases, leakage through the prosthesis was the reason for replacement. No differences were found in the total flow, volume range and intratracheal pressure (ITP) of the voice prostheses measured. The airflow resistance of biofilm covered prostheses was significantly reduced compared to new clean prostheses. However, no correlation was found between the extent of biofilm and the different aerodynamic features measured. Biofilm formation on the Provox 2 is responsible for both reduction in airflow resistance and leakage through the prosthesis by deterioration of the silicone rubber material. 相似文献
992.
993.
Sun Ren-yu孙仁宇 Yan Yi-zhao严仪昭 Zhang Hong张宏and Li Chang-cheng李长城Institute cf Basic Metiical Sciences Chinee Academy of Medical Sciences Beijing 《中华医学杂志(英文版)》1989,102(1):1-6
Acute pulmonary hypertension was caused by
inhalation of 5% 02 in rats. Pulmonary vascujar re-
sistance (PVR) increased, but heart rate (HR), cardiac
output (CO) and carotid arterial pressure (CAP) were
not obviously changed. After an intravenous admini-
stration of Radix Angelicae sinensis, the acute
pulmonary hypertension induced by inhalation of 5%
O2 could be attenuated, but this effect disappeared if
propranolol was given before Radix Angelicae sinensis.
In chronic experiments, the same results were
obtained, but the protective effect of Radix Angelicae
sinensis on heart function was not influenced by
propranolol. It is suggested that Radix Angelicae
sinensis rmght play a role by stimulating the
βz-receptor in the prevention of acute and chronic
hypoxic pulmonary hypertension. However, prevention
of hypertrophy of the right ventricle and enhancement
of heart function in chronic hypoxic rats might not be
attributed to the β1 receptor in the heart. 相似文献
994.
The effects of localized gamma-irradiation on the in vivo 31P NMR spectra of RIF-1 tumors grown subcutaneously in C3H/HeN mice have been examined before and during the week after treatment. Increases in the ratio of phosphocreatine (PCr) to inorganic phosphate (Pi) and in tumor pH, and decreases in the ratio of Pi to the beta phosphorus resonance of the nucleotide triphosphates (beta NTP) were observed in irradiated tumors. The time course of changes in the 31P spectrum following treatment was the opposite of the pattern during untreated growth, and the magnitude and duration of the changes increased with increasing radiation dose, decreasing clonogenic cell survival and increasing growth delay. To examine the possibility that nontherapeutic systemic effects of the tumor irradiation were responsible for the changes observed, a number of animals bearing two tumors were examined. One tumor on each mouse was selectively irradiated. Changes in tumor volume, Pi/beta NTP, PCr/Pi, the ratio of phosphomonoesters to beta NTP, and tumor pH were all significantly different in the treated compared to the untreated tumor on each animal, indicating that these changes in 31P NMR spectra were a response to radiation therapy and not a systemic response to radiation toxicity. 相似文献
995.
Lou Zhong-jin罗仲金 Wang Ling王玲 Liu Qing 刘庆Tian Guang-zhao田光兆 Hu Xiao-su胡孝素 Huang Guang-qi黄光琦Qian Fang钱方 Ran Rui-tu冉瑞图West China University of Medical Sciences ChengduHuang De-huai黄德淮Chengdu Fifth People''s Hospital Chengdu 《中华医学杂志(英文版)》1987,100(9):740-744
Comparative studies are made on the relative
percentages of amino acid content and LDH isozyme
by electrophoresis and Slab-PAGE in adult worms
of Ascaris lumbricoides, Ascaris suum and Toxocara
canis. The results show that there are remarkable
differences of Arg and His of 17 amino acids bet.
ween Toxocara canis and human intestinal ascaris,
human biliary ascaris and pig ascaris; there are also
obvious differences of band positions of LDH
isozyme electrophoretic patterns and band position
and amount of slab-PAGE patterns among them,
whereas no marked differences are found in these
three indices in human intestinal ascaris, human
biliary ascaris and pig ascaris. 相似文献
996.
The historical review and the necessity of establishment of the Chinese Classification of Diseases (CCD) and Coding System are described. The content, terms used for unified and standardized nomenclatures, coding system including diagnostic terms of traditional Chinese medicine and other codings are introduced. The utility of the CCD system in medical record face sheet management, national native medical statistics, consultative retrieval from terms and codes of diseases, the development and practical trial of ICD-9 CCD is also discussed. Finally, the position and prospect of CCD system in international informatics communication is emphasized. 相似文献
997.
998.
999.
1000.