全文获取类型
收费全文 | 4369篇 |
免费 | 179篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 71篇 |
妇产科学 | 23篇 |
基础医学 | 446篇 |
口腔科学 | 174篇 |
临床医学 | 264篇 |
内科学 | 1217篇 |
皮肤病学 | 55篇 |
神经病学 | 209篇 |
特种医学 | 111篇 |
外科学 | 849篇 |
综合类 | 11篇 |
预防医学 | 122篇 |
眼科学 | 59篇 |
药学 | 456篇 |
中国医学 | 26篇 |
肿瘤学 | 484篇 |
出版年
2023年 | 21篇 |
2022年 | 49篇 |
2021年 | 100篇 |
2020年 | 34篇 |
2019年 | 47篇 |
2018年 | 70篇 |
2017年 | 57篇 |
2016年 | 82篇 |
2015年 | 95篇 |
2014年 | 104篇 |
2013年 | 129篇 |
2012年 | 189篇 |
2011年 | 214篇 |
2010年 | 135篇 |
2009年 | 74篇 |
2008年 | 189篇 |
2007年 | 223篇 |
2006年 | 192篇 |
2005年 | 208篇 |
2004年 | 195篇 |
2003年 | 159篇 |
2002年 | 162篇 |
2001年 | 149篇 |
2000年 | 148篇 |
1999年 | 138篇 |
1998年 | 54篇 |
1997年 | 42篇 |
1996年 | 43篇 |
1995年 | 44篇 |
1994年 | 24篇 |
1993年 | 30篇 |
1992年 | 89篇 |
1991年 | 108篇 |
1990年 | 94篇 |
1989年 | 95篇 |
1988年 | 98篇 |
1987年 | 85篇 |
1986年 | 80篇 |
1985年 | 89篇 |
1984年 | 45篇 |
1983年 | 50篇 |
1982年 | 27篇 |
1981年 | 25篇 |
1980年 | 28篇 |
1979年 | 39篇 |
1978年 | 23篇 |
1977年 | 20篇 |
1973年 | 25篇 |
1970年 | 21篇 |
1969年 | 26篇 |
排序方式: 共有4592条查询结果,搜索用时 15 毫秒
141.
The efficiency of interference of Potato virus X infection depends on the target gene 总被引:3,自引:0,他引:3
Takahashi S Komatsu K Kagiwada S Ozeki J Mori T Hirata H Yamaji Y Ugaki M Namba S 《Virus research》2006,116(1-2):214-217
RNA silencing is a natural defense response against viral infection. This phenomenon has been used to interfere with viral infections by exploiting fragments of viral genomes as sources of RNA silencing. Agrobacterium-mediated transient expression of a hairpin RNA derived from the TGBp1 gene of Potato virus X (PVX) induced RNA silencing of the TGBp1 gene and resulted in interference of PVX infection. The interference was induced in the infiltrated leaves but not in the upper non-infiltrated leaves. Transient expression of a CP hairpin RNA also induced interference of PVX. The TGBp1 hairpin RNA showed more efficient interference of PVX infection than the CP hairpin RNA. 相似文献
142.
Hiejima E Komatsu H Takeda Y Sogo T Inui A Okafuji I Nishikomori R Nakahata T Fujisawa T 《Journal of paediatrics and child health》2012,48(3):E122-E125
Acute liver failure (ALF) with macrophage activation syndrome (MAS) is well known as a complication of systemic-onset juvenile idiopathic arthritis (S-JIA). However, liver failure without overt MAS is rare in S-JIA. We encountered two Japanese children with S-JIA in whom ALF developed during the remission of clinical manifestations. ALF without MAS was improved with plasma exchange and cyclosporine A combined with pulse methylprednisolone. 相似文献
143.
Hiroki Sugihara Ikuya Murakami Krishna V Shenoy Richard A Andersen Hidehiko Komatsu 《Journal of neurophysiology》2002,87(1):273-285
We studied whether the dorsal division of the medial superior temporal area (MSTd) in the macaque has activity related to structure-from-motion (SFM) processing. As the simplest form of three-dimensional (3D) structure, we chose a planar stimulus and examined the relation between the neural responses and the simulated 3D orientation of the plane defined by motion cues. We recorded from 114 MSTd neurons while monkeys were performing a visual fixation task. These neurons responded to a basic set of optic flow patterns such as translation, expansion/contraction, and rotation. Responses of these neurons to rotating plane stimuli were examined to see whether the MSTd neurons exhibited selectivity to the tilt and slant that characterize the 3D orientation of the plane. We found that most MSTd neurons tested (97 of 114) responded to the plane stimuli, and many neurons (65 of 97) exhibited selectivity to tilt and/or slant. Of 97 neurons, 18% (17/97) were selective only to tilt, 24% (23/97) only to slant, and 26% (25/97) to both. Control experiments rejected the possibility that the selectivity could be explained solely by the sensitivity to local stimulus components such as local translation, local speed, and local speed gradients. These results suggest that MSTd neurons are sensitive to stimulus features specific to the perceived 3D orientation of the rotating plane stimuli and suggest that area MSTd is involved in SFM processing. 相似文献
144.
Preponderance of hepatitis B virus genotype B contributes to a better prognosis of chronic HBV infection in Okinawa,Japan 总被引:11,自引:0,他引:11
Sakugawa H Nakasone H Nakayoshi T Orito E Mizokami M Yamashiro T Maeshiro T Kinjo F Saito A Miyagi Y 《Journal of medical virology》2002,67(4):484-489
The present study was designed to examine the distribution of hepatitis B virus (HBV) genotypes among patients at various stages of chronic liver disease type B in Okinawa Prefecture, Japan, where the prevalence of hepatitis B surface antigen is the highest in Japan despite the lowest mortality rate from primary liver cancer. Serum samples from 227 HBV carriers were determined for HBV genotype by polymerase chain reaction (PCR)-restriction fragment length polymorphism. Five of 227 sera were negative for HBV DNA by nested PCR and were excluded from the genotype analysis. Genotype B was predominant in asymptomatic carriers (45/67, 67%), whereas genotype C was predominant in chronic liver disease: 49% (50/103) in patients with chronic hepatitis, 63% (20/32) in patients with cirrhosis, and 60% (12/20) in patients with hepatocellular carcinoma. The distribution of genotype B decreased with increasing liver disease severity. However, this tendency was seen among patients aged less than 50 years old, whereas the prevalence of genotype B was similar among carriers with various liver diseases who were older than age 50. In conclusion, HBV genotype B was prevalent and less frequent among patients with advanced liver disease, particularly in patients aged less than 50 years. These findings suggest that the preponderance of genotype B is responsible for the low mortality rate of primary liver cancer associated with HBV seen in Okinawa Prefecture, despite having the highest HBV carrier rate in Japanese. 相似文献
145.
146.
Susumu Morita Satoru Joshita Takeji Umemura Yoshihiko Katsuyama Takefumi Kimura Michiharu Komatsu Akihiro Matsumoto Kaname Yoshizawa Astushi Kamijo Nobuyoshi Yamamura Eiji Tanaka Masao Ota 《Human immunology》2013
Primary biliary cirrhosis (PBC) is characterized by portal inflammation and immune-mediated destruction of intrahepatic bile ducts that often result in liver failure. Toll-like receptor (TLR) 4 recognizes lipopolysaccharides of Gram-negative bacteria. Infectious agents have been suspected to play a crucial role in PBC pathogenesis since TLR4 expression was found in bile duct epithelial cells and periportal hepatocytes in liver tissues of PBC. To assess the potential contribution of TLR4 SNPs to the development of this disease, we genotyped five SNPs in TLR4 in 261 PBC patients and 359 controls using a TaqMan assay. No significant positive associations with either PBC susceptibility or progression were uncovered. These results indicate that TLR4 polymorphisms do not play a prominent role in the development of PBC in Japanese patients. 相似文献
147.
148.
Demura S Morishita K Yamada T Yamaji S Komatsu M 《European journal of applied physiology》2011,111(11):2837-2843
l-Ornithine plays an important role in ammonia metabolism via the urea cycle. This study aimed to examine the effect of l-ornithine hydrochloride ingestion on ammonia metabolism and performance after intermittent maximal anaerobic cycle ergometer
exercise. Ten healthy young adults (age, 23.8 ± 3.9 year; height, 172.3 ± 5.5 cm; body mass, 67.7 ± 6.1 kg) with regular training
experience ingested l-ornithine hydrochloride (0.1 g/kg, body mass) or placebo after 30 s of maximal cycling exercise. Five sets of the same maximal
cycling exercise were conducted 60 min after ingestion, and maximal cycling exercise was conducted after a 15 min rest. The
intensity of cycling exercise was based on each subject’s body mass (0.74 N kg−1). Work volume (watt), peak rpm (rpm) before and after intermittent maximal ergometer exercise and the following serum parameters
were measured before ingestion, immediately after exercise and 15 min after exercise: ornithine, ammonia, urea, lactic acid
and glutamate. Peak rpm was significantly greater with l-ornithine hydrochloride ingestion than with placebo ingestion. Serum ornithine level was significantly greater with l-ornithine hydrochloride ingestion than with placebo ingestion immediately and 15 min after intermittent maximal cycle ergometer
exercise. In conclusion, although maximal anaerobic performance may be improved by l-ornithine hydrochloride ingestion before intermittent maximal anaerobic cycle ergometer exercise, the above may not depend
on increase of ammonia metabolism with l-ornithine hydrochloride. 相似文献
149.
Shiomoto A Akazawa H Okada T Yano S Oya N Ogawa K Komatsu R Morimoto M Takakura T 《Nihon Hoshasen Gijutsu Gakkai zasshi》2004,60(3):429-436
In radiation therapy for keloid, electron beams are delivered to the skin through a lead shield hollowed into the shape of the keloid. The shape of a postoperative keloid scar is linear, causing the irradiation shield to be long and narrow. This lead shield is put on the surface of the skin. Therefore, it is considered that beam data used in general external irradiation are not applicable to irradiation for keloid. Therefore, we used a water equivalent phantom and measured beam data by using chambers or film dosimeters. Experimental conditions were the same as those of actual radiotherapy for keloid. As a result of this procedure, the radiation technique was optimized. Electron energy and thickness of the bolus, thickness of the lead shield, margins such that the planning target volume would receive the necessary dose, and the method of MU calculation all were determined. It was suggested that these experiments were useful to establish the appropriate technique in irradiation for keloid. 相似文献
150.
Masahiko Sato Kazuhira Maehara Hiroyuki Yaoita Hiroshi Otani Akira Hirosaka Tomiyoshi Saito Norio Onuki Nobuo Komatsu Takako Ishihata Yukio Maruyama 《Journal of nuclear medicine》2003,44(10):1618-1624
Cardiac (123)I-metaiodobenzylguanidine ((123)I-MIBG) uptake is reduced in chronic heart failure, and its reduction is reported to relate to the decrease in exercise capacity. Reduced (123)I-MIBG uptake may predict an inadequately reduced adrenergic drive to the heart during cardiac sympathetic stimulation, including exercise. However, there is little information about the relationship between cardiac (123)I-MIBG uptake at rest and norepinephrine (NE) release during exercise in relation to the exercise capacity in the failing heart. The aim of this study was to examine whether cardiac (123)I-MIBG uptake at rest can predict cardiac sympathetic activity during exercise in patients with chronic heart failure. We determined how cardiac (123)I-MIBG uptake at rest relates to NE overflow from the heart during symptom-limited graded exercise in such patients. METHODS: Twelve patients (mean +/- SD, 52 +/- 12 y) with chronic stable heart failure performed symptom-limited graded exercise tests under catheterizations with a 4-min stage using a supine bicycle ergometer within 2 wk after (123)I-MIBG imaging. NE concentrations in the arterial and coronary sinus blood (NE(A) and NE(CS), respectively) were measured at each exercise stage, and NE overflow was approximated by the difference between NE(CS) and NE(A) (NE(CS-A)). RESULTS: The left ventricular ejection fraction at rest was 47% +/- 16% and peak oxygen uptake was 17.7 +/- 5.1 mL/kg/min. The heart-to-mediastinum uptake ratio of the delayed (123)I-MIBG image (1.00 - 1.72; mean +/- SD, 1.30 +/- 0.19) correlated with NE(CS-A) at peak exercise (r = 0.80, P < 0.01) and peak heart rate (r = 0.73, P < 0.01) but not with peak oxygen uptake. CONCLUSION: Cardiac (123)I-MIBG uptake of the delayed image can predict the degree of the increase in adrenergic drive to the heart during sympathetic stimuli induced by exercise in patients with chronic heart failure. 相似文献