全文获取类型
收费全文 | 25073篇 |
免费 | 1189篇 |
国内免费 | 175篇 |
专业分类
耳鼻咽喉 | 195篇 |
儿科学 | 509篇 |
妇产科学 | 195篇 |
基础医学 | 3276篇 |
口腔科学 | 461篇 |
临床医学 | 1680篇 |
内科学 | 6584篇 |
皮肤病学 | 517篇 |
神经病学 | 2095篇 |
特种医学 | 1081篇 |
外科学 | 4157篇 |
综合类 | 96篇 |
预防医学 | 707篇 |
眼科学 | 500篇 |
药学 | 1662篇 |
中国医学 | 80篇 |
肿瘤学 | 2642篇 |
出版年
2023年 | 130篇 |
2022年 | 271篇 |
2021年 | 515篇 |
2020年 | 271篇 |
2019年 | 415篇 |
2018年 | 515篇 |
2017年 | 436篇 |
2016年 | 536篇 |
2015年 | 545篇 |
2014年 | 704篇 |
2013年 | 879篇 |
2012年 | 1473篇 |
2011年 | 1640篇 |
2010年 | 870篇 |
2009年 | 755篇 |
2008年 | 1413篇 |
2007年 | 1620篇 |
2006年 | 1518篇 |
2005年 | 1689篇 |
2004年 | 1658篇 |
2003年 | 1645篇 |
2002年 | 1506篇 |
2001年 | 502篇 |
2000年 | 474篇 |
1999年 | 514篇 |
1998年 | 350篇 |
1997年 | 274篇 |
1996年 | 228篇 |
1995年 | 219篇 |
1994年 | 175篇 |
1993年 | 174篇 |
1992年 | 239篇 |
1991年 | 233篇 |
1990年 | 230篇 |
1989年 | 213篇 |
1988年 | 200篇 |
1987年 | 169篇 |
1986年 | 159篇 |
1985年 | 145篇 |
1984年 | 105篇 |
1983年 | 113篇 |
1982年 | 58篇 |
1981年 | 61篇 |
1980年 | 51篇 |
1979年 | 80篇 |
1978年 | 58篇 |
1976年 | 35篇 |
1975年 | 51篇 |
1974年 | 37篇 |
1970年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Takuro Yoshikawa Yasuyuki Suzuki Yasuhiro Fujino Keitaro Kakinoki Shiri Li Tadahiro Goto Tomohiro Tanaka Ippei Matsumoto Tetsuya Sakai Yasuki Tanioka Hiroshi Yokozaki Yoshikazu Kuroda 《American journal of transplantation》2005,5(9):2135-2142
Small bowel transplantation (SBT) is associated with a high incidence of infectious complications because of ischemia/reperfusion (I/R) mucosal injury concomitant with potent immunosuppression. In this study, we evaluated whether the cavitary two-layer method (cTLM) could reduce I/R injury and allow early mucosal restoration, particularly after prolonged preservation and transplantation. Canine heterotopic segmental SBT was performed immediately without preservation (group 1), after 24-h preservation in UW solution (group 2) or by the cTLM (group 3). The graft samples were taken 1 h after reperfusion and on days 1, 4 and 7. We assessed graft mucosa with detailed microscopic and electromicroscopic analyses. In Group 3, histological injury and cell apoptosis after transplantation were significantly alleviated and rapidly recovered to a similar level of group 1. The mucosal restoration was morphologically completed within 4 days. In contrast, in group 2, more pronounced mucosal injury and delayed recovery were noted. Crypt cell proliferation activity was well maintained in groups 1 and 3 throughout the experimental period. Our ultrastructural analysis suggested that mitochondrial integrity achieved by the cTLM was a basal mechanism under the prompt mucosal restoration. The cTLM could reduce I/R injury, facilitate mucosal regeneration and restore the nearly normal structure early after SBT. 相似文献
52.
Hirotaka Inaba Kazuhiko Higuchi Kenji Koseni Haruo Yamauchi Junichi Naganuma 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(11):587-592
OBJECTIVE: The aortic connector system was used to minimize cerebrovascular complications when performing the proximal anastomosis of vein grafts during coronary artery bypass grafting (CABG). The goal of this study was to investigate the intermediate outcomes of patients undergoing CABG with the aortic connector system. METHODS: The aortic connector was used on nine patients undergoing CABG between November 2002 and July 2003. Intermediate outcomes of the patients were examined, and the results of coronary angiography, which were performed before patient discharge and at least 6 months after discharge, were evaluated. RESULTS: There were no operative deaths or cerebrovascular accidents. One patient died 9 months after discharge, one patient had angina, and the remaining seven patients were asymptomatic. When evaluating the results of angiography performed before patient discharge, two of the 21 distal vein graft anastomoses were occluded (patency rate, 90.5%), but there was no stenosis or occlusion at the proximal anastomoses sites that were performed using the aortic connector. When evaluating the results of the second angiography performed after patient discharge, four of the eight proximal anastomoses were patent, one was completely occluded, two had 90% stenosis and one had 75% stenosis. Further, four of the 18 distal anastomoses were occluded (patency rate, 77.8%). There was no significant difference in graft flow or device size when comparing patients with patent vein grafts and those with stenotic or occluded vein grafts. CONCLUSION: Intermediate outcomes of vein grafting using the aortic connector were suboptimal. Long-term outcome data are forthcoming. 相似文献
53.
Yoshitaka Hirooka Yoshikuni Kimura Masatsugu Nozoe Yoji Sagara Koji Ito Kenji Sunagawa 《Hypertension research》2006,29(1):49-56
Amlodipine is a dihydropyridine calcium channel blocker that is widely used for the treatment of hypertensive patients and has an antioxidant effect on vessels in vitro. The aim of the present study was to examine whether treatment with amlodipine reduced oxidative stress in the brains of stroke-prone spontaneously hypertensive rats (SHRSP). The animals received amlodipine, nicardipine or hydralazine for 30 days in their drinking water. Levels of thiobarbituric acid-reactive substances (TBARS) in the brain (cortex, cerebellum, hypothalamus, and brainstem) were measured before and after each treatment. Systolic blood pressure decreased to similar levels in the amlodipine-, nicardipine-, and hydralazine-treated groups. Urinary norepinephrine excretion was significantly reduced in SHRSP after treatment with amlodipine, but not with nicardipine or hydralazine. Levels of TBARS in the cortex, cerebellum, hypothalamus, and brainstem were significantly higher in SHRSP than in Wistar-Kyoto rats (WKY), and were reduced in amlodipine-treated, but not in nicardipine- or hydralazine-treated, SHRSP. Electron spin resonance spectroscopy revealed increased levels of reactive oxygen species in the brains of SHRSP, which were reduced by treatment with amlodipine. Intracisternal infusion of amlodipine also reduced systolic blood pressure, urinary norepinephrine excretion, and the levels of TBARS in the brain. These results suggested that oxidative stress in the brain was enhanced in SHRSP compared with WKY rats. In addition, antihypertensive treatment with amlodipine reduced oxidative stress in all areas of the brain examined and decreased blood pressure without a reflex increase in sympathetic nerve activity in SHRSP. 相似文献
54.
Positron emission tomography was performed on six patients with Rett syndrome to investigate cerebral blood flow and oxygen metabolism, and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO2) was low in five patients, and oxygen extraction fraction was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both cerebral blood flow and CMRO2 were lower than those for the controls, which may indicate the loss of hyperfrontality in Rett syndrome. 相似文献
55.
Toyohiro Kagawa Fumiko Fukunari Tomoko Shiraishi Miwako Yamasaki Takahiro Ichihara Yuka Kihara Ryousuke Zeze Kentaro Nogami Kenji Yuasa 《Oral Radiology》2006,22(2):47-51
Objectives To develop a simple image viewer that utilizes image files in general-purpose formats that are written from the original 3DX
volume data.
Methods We used FLASH MX2004 for Macintosh to develop a simple image viewer. In developing the software for the simple image viewer,
we decided that the viewer should provide the following features: (1) be available to both Windows OS and Mac OS, (2) allow
interlocking of the 3D images, (3) display image enlargement, and (4) allow distance measurements. The accuracy of the distance
measurements was evaluated.
Results The procedure was as follows: (1) write 3D images in jpeg format to a folder on i-VIEW; (2) place the folder containing the
3D images into the directory of the simple image viewer software on a PC; (3) start the software and open the window to input
the folder name containing the 3D images; and (4) display the 3D images. Our viewer had features such as image enlargement,
interlocking 3D images, drawing, and distance measurements. No significant differences were shown between the measurements
made by our simple viewer and the actual values of the images in any direction.
Conclusions Our image-viewing software for 3DX is beneficial for clinical use. 相似文献
56.
Kunihiro Ichinose Mitsuru Nakamura Kenji Takezawa Ichiro Masutomi Yoichi Shima Yoko Hirayama Kahoko Sorimachi Teruhiko Shimizu Hiroyo Ishikawa Namiko Kaji Sayaka Nakajima Michiko Wataru Shiho Nishigaki Hiroshi Suwa Yosuke Toyama Masaki Okumura Yoshikazu Ishitsuka Ken Shimizu Kazuya Kokubo Kenji Sasaki Shodai Saito 《Seishin shinkeigaku zasshi》2006,108(9):945-954
57.
Resolution of homonymous visual field loss documented with functional magnetic resonance and diffusion tensor imaging. 总被引:5,自引:0,他引:5
Masaki Yoshida Masahiro Ida Thien Huong Nguyen Marie-Therese Iba-Zizen Luc Bellinger Jean Louis Stievenart Takehiko Nagao Shinsuke Kikuchi Takaaki Hara Takuya Shiba Kenji Kitahara Emmanuel Alain Cabanis 《Journal of neuro-ophthalmology》2006,26(1):11-17
A 68-year-old man developed right homonymous hemianopic paracentral scotomas from acute infarction of the left extrastriate area. He was studied over the ensuing 12 months with visual fields, conventional MRI, functional MRI (fMRI), and diffusion tensor imaging (DTI). As the visual field defect became smaller, fMRI demonstrated progressively larger areas of cortical activation. DTI initially showed that the lesioned posterior optic radiations were completely interrupted. This interruption lessened in time and had disappeared by one year after onset. fMRI and DTI are innovative measures to follow functional and structural recovery in the central nervous system. This is the first reported application of these imaging techniques to acute cerebral visual field disorders. 相似文献
58.
Kenji Tsukada Shigeru Kobayashi Tatsuya Gotoh Naoki Asakage Masayuki Sekine Morio Sasaki Eiji Miyazaki Takahisa Suzuki Toshio Yamada Shu Hirai Shigetaka Yamazaki 《Digestive endoscopy》2006,18(1):55-58
A case of early gastric carcinoma accompanied by Dieulafoy ulcer is presented. The patient, a 26‐year‐old female, visited our emergency room with chief complaints of massive hematemesis and tarry stool. The initial endoscopic examination revealed a superficial depressed lesion with a faded color accompanied by a tiny ulcer with converging folds at the anterior wall of the middle gastric body. Although no active bleeding vessel was found at that time, the patient was admitted to our hospital for further check‐ups and treatment. On the 6th hospital day, she developed massive hematemesis resulting in shock. Urgent endoscopy, this time, disclosed an exposed bleeding vessel at the small ulcer floor previously mentioned, and endoscopic hemostasis was achieved. Since, however, a biopsy at initial examination from the surrounding depressed area proved carcinoma, a partial distal gastrectomy was subsequently carried out. Histological examination of the resected specimen confirmed the diagnosis of carcinoma limited to the mucosa and submucosa along with findings consistent with Dieulafoy ulcer. This is a rare case of combination of early cancer and Dieulafoy ulcer particularly in such a young patient. A review of the literature is also presented. 相似文献
59.
Ryo Hattori MD Tateki Kubo MD Kenji Yano MD PhD Atsushi Tanemura MD Yuji Yamaguchi MD PhD Satoshi Itami MD PhD Ko Hosokawa MD PhD 《Dermatologic surgery》2003,29(10):1071-1072
BACKGROUND: Nevus lipomatosus cutaneous superficialis (NLCS) is a relatively rare condition. Although NLCS can affect any region of the entire body, no case of NLCS in the clitoris has ever been reported. OBJECTIVE: To report a case of NLCS of the clitoris that presented manifestations that were similar to female pseudohermaphrodism. METHODS: This is a case report and review of the literature. RESULTS: A congenital, soft, skin-colored lesion of the clitoris in a 1-year-old girl resembled female pseudohermaphrodism. It was resected, and the histologic diagnosis was NLCS. Postoperatively, there was no subsequent change in the lesion during the 3-year follow-up period. CONCLUSION: We reported a case of congenital solitary NLCS of the clitoris. Although NLCS might be a relatively rare condition, we should consider it in the differential diagnosis of female pseudohermaphrodism. 相似文献
60.
Yasuomi Ouchi Teiji Nakayama Toshihiko Kanno Etsuji Yoshikawa Tomomi Shinke Tatsuo Torizuka 《Journal of cerebral blood flow and metabolism》2007,27(4):803-810
Differentiation of impaired gait seen in idiopathic normal pressure hydrocephalus (iNPH) from parkinsonian gait is sometimes a great challenge and important for future medication in the clinical setting. To investigate dopaminergic contribution to its pathophysiology, two aspects of the trans-synaptic dopamine functions in the striatal region in eight iNPH patients na?ve to dopaminergic drugs were examined using positron emission tomography with a presynaptic marker [11C]CFT ([11C]2-beta-carbomethoxy-3beta-(4-fluorophenyl) tropane) that binds to dopamine transporter and a postsynaptic marker [11C]raclopride that binds to D2 receptor. Quantitative values of binding potentials (BPs) for [11C]CFT and [11C]raclopride were compared between patients and eight age-matched healthy subjects. The BPs and magnetic resonance imaging-based morphometric measures in iNPH were used for correlation analyses between the magnitude of binding of these in vivo markers and clinical severity of the patients. Analysis of variance showed significant reduction in [11C]raclopride binding in the putamen and nucleus accumbens (P<0.05, corrected for multiple comparison) and unchanged striatal [11C]CFT binding in iNPH. The dorsal putamen [11C]raclopride binding correlated negatively with gait severity (r=0.720, P<0.05), and the nucleus accumbens [11C]raclopride binding correlated positively with emotional recognition score (r=0.727, P<0.05) in the disease group. No significant relationship was observed between BPs and morphometric measures. The current result of the postsynaptic D2 receptor reduction along with preserved presynaptic activity in the nigrostriatal dopaminergic system reflects a pathophysiology of iNPH. Postsynaptic D2 receptor hypoactivity in the dorsal putamen may predict the severity of gait impairment in iNPH. 相似文献