全文获取类型
收费全文 | 41912篇 |
免费 | 1937篇 |
国内免费 | 188篇 |
专业分类
耳鼻咽喉 | 713篇 |
儿科学 | 693篇 |
妇产科学 | 756篇 |
基础医学 | 5511篇 |
口腔科学 | 1256篇 |
临床医学 | 2930篇 |
内科学 | 9826篇 |
皮肤病学 | 584篇 |
神经病学 | 3473篇 |
特种医学 | 1383篇 |
外科学 | 7148篇 |
综合类 | 186篇 |
一般理论 | 2篇 |
预防医学 | 1553篇 |
眼科学 | 674篇 |
药学 | 3521篇 |
中国医学 | 88篇 |
肿瘤学 | 3740篇 |
出版年
2023年 | 210篇 |
2022年 | 449篇 |
2021年 | 766篇 |
2020年 | 382篇 |
2019年 | 530篇 |
2018年 | 630篇 |
2017年 | 488篇 |
2016年 | 594篇 |
2015年 | 632篇 |
2014年 | 831篇 |
2013年 | 1096篇 |
2012年 | 1789篇 |
2011年 | 1879篇 |
2010年 | 1098篇 |
2009年 | 900篇 |
2008年 | 1802篇 |
2007年 | 1911篇 |
2006年 | 1878篇 |
2005年 | 1852篇 |
2004年 | 1793篇 |
2003年 | 1826篇 |
2002年 | 1777篇 |
2001年 | 1627篇 |
2000年 | 1782篇 |
1999年 | 1498篇 |
1998年 | 482篇 |
1997年 | 391篇 |
1996年 | 364篇 |
1995年 | 302篇 |
1994年 | 279篇 |
1993年 | 253篇 |
1992年 | 1106篇 |
1991年 | 918篇 |
1990年 | 902篇 |
1989年 | 941篇 |
1988年 | 834篇 |
1987年 | 830篇 |
1986年 | 781篇 |
1985年 | 770篇 |
1984年 | 527篇 |
1983年 | 423篇 |
1982年 | 217篇 |
1979年 | 482篇 |
1978年 | 274篇 |
1977年 | 251篇 |
1975年 | 207篇 |
1974年 | 223篇 |
1971年 | 230篇 |
1969年 | 230篇 |
1968年 | 216篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
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
43.
44.
45.
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
46.
Yutaka Ejima Yoko Hasegawa Satoru Sanada Noriyuki Miyama Ryo Hatano Tomohiro Arata Michiko Suzuki Itsuro Kazama Akira Sato Susumu Satomi Wataru Hida Mitsunobu Matsubara 《Hypertension research》2006,29(4):261-267
Since the prevalence and clinical characteristics of young-onset hypertension are still to be elucidated, we performed targeted-screening at an annual university health check-up for two consecutive years. Out of 16,464 subjects in 2003 and 17,032 in 2004 that were aged less than 30 years, 22 and 26 students (all males) exhibited high blood pressure (BP), respectively, on three occasions during casual BP measurements at the Tohoku University Health Center (systolic and diastolic BP of 140 and/or 90 mmHg or greater, respectively). These students were asked to measure their BP at home, and 9 subjects in total were diagnosed as having essential hypertension (EH). The remaining students were diagnosed as having white coat hypertension (WCH). In 8 out of 9 EH students, their father and/or mother had also been treated with antihypertensive medication. Adjustment by attendance ratio for each BP measurement suggested that the incidence of EH was around 0.1% and that of hypertension (EH and WCH) was around 0.5% in university students aged less than 25 years, since most of the subjects and hypertensive students were between 18 and 24 years old. Body mass index of the EH, which was more than 25 kg/m2 (overweight), was significantly higher than that with WCH. In conclusion, the combination of repeated casual BP measurements and home BP effectively identified young-onset EH. The clinical parameters indicated that male gender, genetic background, and excessive weight were risk factors for young-onset hypertension. 相似文献
47.
p53 mutations in non-small cell lung cancer in Japan: association between mutations and smoking. 总被引:20,自引:0,他引:20
H Suzuki T Takahashi T Kuroishi M Suyama Y Ariyoshi T Takahashi R Ueda 《Cancer research》1992,52(3):734-736
The p53 gene has been implicated as a tumor suppressor gene involved in the pathogenesis of lung cancer. Our previous study revealed that the p53 gene is frequently mutated with a distinct nucleotide substitution pattern in small cell lung cancer specimens in Japanese patients. In this study, we examined 30 primary, resected non-small cell lung cancer samples in Japanese patients using complementary DNA-polymerase chain reaction and sequencing. Mutations changing the p53 coding sequence were found in 14 of 30 tumor samples (47%), while G:C to T:A transversions which are uncommon in other cancers such as colon cancer were the most frequently observed mutations, in agreement with an earlier report on non-small cell lung cancer in American patients. Furthermore, the present study shows for the first time that in univariate and multivariate analyses, the presence of p53 mutations is closely associated with lifetime cigarette consumption. 相似文献
48.
Squamous cell carcinoma of the thyroid--a report of three cases 总被引:1,自引:0,他引:1
A Tsuchiya S Suzuki T Nomizu Y Yamaki R Abe S Katayama 《The Japanese journal of surgery》1990,20(3):341-345
Three cases of squamous cell carcinoma of the thyroid are reported herein. In all cases, the carcinoma occurred in old age and was characterized by a rapidly growing tumor, usually associated with dyspnea and dysphagia. The prognosis of all 3 cases was poor, with a mean survival of only 6.3 months. Although squamous metaplasia is an accepted etiology of this disease, clinical investigation of the cases presented here does not favor it in consideration of the clinical features of papillary carcinoma of the thyroid with squamous metaplasia. The histological findings of our cases revealed areas of cystic formation, suggesting that some of these carcinomas may be derived from remnants of embryonic origin. 相似文献
49.
Tomotaka Sobue Takaichiro Suzuki Tsuguo Naruke The Japanese Lung Cancer Screening Research Group 《Cancer science》1992,83(5):424-430
A case-control study to evaluate the efficacy of lung cancer screening conducted by us showed that lung cancer screening may reduce the mortality of the disease up to 28%. Assuming this efficacy is unbiased, and that the screening rate is 51.6%, which was observed in the control group in the above study, the number of lung cancer deaths prevented by screening in the study period was calculated to be 47 for males and females combined. In the same study population, screen-detected lung cancer patients (N = 207) in the same study period were followed and the 7-year survival rate (46.9%) was compared to the 5-year survival rate (11.3%) obtained by the Osaka Cancer Registry, in which screen-detected lung cancer patients were only 1.8%. The number of lung cancer deaths prevented by screening, estimated by the difference in the above two survival rates, was 74 (95% confidence interval; 55–93). The number of lung cancer deaths prevented by screening estimated from the case-control study was significantly lower than that estimated from the survival analysis. This indicates that the efficacy of lung cancer screening estimated by the case-control study was within the range that could be explained by the actual long-term survivors among the screen-detected patients in the study population. 相似文献
50.
MRI of ossification of ligamentum flavum. 总被引:11,自引:0,他引:11
H Sugimura Y Kakitsubata Y Suzuki S Kakitsubata S Tamura O Uwada T Kodama T Yano K Watanabe 《Journal of computer assisted tomography》1992,16(1):73-76
Magnetic resonance imaging of 28 patients with radiological and/or histopathologically proved ossification of the ligamentum flavum (OLF) was reviewed. The locations of OLF were cervical (n = 4), thoracic (n = 22), and lumbar (n = 2). On T1- and T2-weighted images, OLF demonstrated low signal intensity. Areas of high or intermediate signal intensity within the OLF on T1-weighted images were observed in three cases and were interpreted to be due to fat infiltration. In six cases, high intensity areas in the spinal cord caused by compressing OLF were demonstrated on T2-weighted images. Gadolinium-diethylenetriamine pentaacetic acid, which was used in four cases, showed cord enhancement at the level of compression by OLF in three cases. 相似文献