全文获取类型
收费全文 | 27927篇 |
免费 | 1352篇 |
国内免费 | 211篇 |
专业分类
耳鼻咽喉 | 228篇 |
儿科学 | 679篇 |
妇产科学 | 216篇 |
基础医学 | 3454篇 |
口腔科学 | 430篇 |
临床医学 | 1722篇 |
内科学 | 7590篇 |
皮肤病学 | 485篇 |
神经病学 | 1889篇 |
特种医学 | 1049篇 |
外科学 | 5114篇 |
综合类 | 106篇 |
预防医学 | 700篇 |
眼科学 | 495篇 |
药学 | 1819篇 |
中国医学 | 40篇 |
肿瘤学 | 3474篇 |
出版年
2023年 | 174篇 |
2022年 | 365篇 |
2021年 | 648篇 |
2020年 | 340篇 |
2019年 | 522篇 |
2018年 | 660篇 |
2017年 | 519篇 |
2016年 | 668篇 |
2015年 | 702篇 |
2014年 | 960篇 |
2013年 | 1084篇 |
2012年 | 1697篇 |
2011年 | 1924篇 |
2010年 | 1091篇 |
2009年 | 904篇 |
2008年 | 1576篇 |
2007年 | 1778篇 |
2006年 | 1788篇 |
2005年 | 1803篇 |
2004年 | 1721篇 |
2003年 | 1681篇 |
2002年 | 1667篇 |
2001年 | 426篇 |
2000年 | 383篇 |
1999年 | 431篇 |
1998年 | 382篇 |
1997年 | 329篇 |
1996年 | 296篇 |
1995年 | 250篇 |
1994年 | 232篇 |
1993年 | 203篇 |
1992年 | 256篇 |
1991年 | 228篇 |
1990年 | 202篇 |
1989年 | 175篇 |
1988年 | 183篇 |
1987年 | 126篇 |
1986年 | 138篇 |
1985年 | 141篇 |
1984年 | 93篇 |
1983年 | 76篇 |
1982年 | 69篇 |
1981年 | 59篇 |
1980年 | 40篇 |
1979年 | 48篇 |
1977年 | 48篇 |
1974年 | 36篇 |
1973年 | 35篇 |
1972年 | 35篇 |
1967年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Shiro Oka Shinji Tanaka Iwao Kaneko Hiroyuki Kanao Kazuaki Chayama 《Digestive endoscopy》2007,19(Z1):S30-S33
Endoscopic submucosal dissection (ESD) for colorectal tumors is steadily being developed. Safety and standardization of ESD for colorectal tumors have not been yet established because of the technical difficulties and the unsuitable anatomical characteristics of the colon and rectum. The authors mainly use a Flex knife for mucosal incision and a Hook knife for submucosal dissection to perform ESD safely. Skillful colonoscopic control, selection of scope, distal attachment tip hood, adequate high‐frequency generator and correct approach strategy should all be considered for safe performance of ESD. However, the incidence of indicative lesions is rare because the majority of colorectal tumors are adenomatous large laterally spreading tumors, which can be cured by intentional endoscopic piecemeal resection. At present, ESD for colorectal tumors should be performed only at central facilities that have expert colonoscopists. With the development of new devices and associated techniques, technical standardization of ESD for colorectal tumors is expected in the near future. 相似文献
42.
Novel SCN5A mutation (Q55X) associated with age-dependent expression of Brugada syndrome presenting as neurally mediated syncope. 总被引:1,自引:0,他引:1
BACKGROUND: An association between Brugada syndrome and neurally mediated syncope has been described. Although mutations in SCN5A have been identified in Brugada syndrome, the genetic link between Brugada syndrome and neurally mediated syncope has not been determined. OBJECTIVES: The purpose of the study was to clinically and genetically characterize a man with recurrent syncope that originally was diagnosed as neurally mediated syncope at age 8 years but subsequently manifested as Brugada syndrome at age 17 years. METHODS: The proband underwent clinical examination, which included head-up tilt test, sodium channel provocation test, and electrophysiologic study. Genetic screening of SCN5A was performed for the proband and his family members. The biophysical properties of a mutant SCN5A channel in a heterologous expression system were studied using whole-cell, patch clamp technique. RESULTS: The proband showed positive head-up tilt test, coved-type ST elevation recorded from the third intercostal space, and positive pilsicainide provocation test. Ventricular fibrillation was inducible at programmed electrical stimulation, consistent with characteristics of both Brugada syndrome and neurally mediated syncope. A novel nonsense SCN5A mutation (Q55X) was identified in the proband, his mother, and his asymptomatic brother. The heterologously expressed mutant channel was nonfunctional. CONCLUSION: We genetically determined an SCN5A mutation in a patient showing the combined phenotype of neurally mediated syncope and Brugada syndrome. Neurally mediated syncope and Brugada syndrome may share, at least in part, a common pathophysiologic mechanism. 相似文献
43.
44.
Shuro Yoshino Takayuki Matsumoto Koichi Kurahara Hiroyuki Kobayashi Mitsuo Iida Tadahiko Fuchigami 《Digestive endoscopy》2006,18(1):59-61
We present a 70‐year‐old man who had two episodes of melena during the preceding 8‐year period. He had a Dieulafoy‐like lesion in a diverticulum in the third portion of the duodenum. While emergency endoscopy revealed neither apparent blood nor clots around the diverticular orifice, there was a non‐bleeding vessel in the fundus of the diverticulum. The vessel ceased bleeding after argon plasma coagulation and, since then, the patient has not experienced bleeding. In cases of gastrointestinal bleeding of obscure origin, duodenal diverticulum should be considered as a possible source of bleeding, even when endoscopy discloses no apparent bleeding. 相似文献
45.
Clinical evaluation of a potassium nitrate dentifrice for the treatment of dentinal hypersensitivity
Toshihiko Nagata Hiroshi Ishida Hiroyuki Shinohara Seiji Nishikawa Shinji Kasahara Yoichi Wakano Shusaku Daigen Emanuel S. Troullos 《Journal of clinical periodontology》1994,21(3):217-221
Abstract The effectiveness of a 5% potassium nitrate dentifrice as a daily home treatment for dentinal hypersensitivity was evaluated in a double-blind study in 36 Japanese subjects who complained of cold and/or tactile hypersensitivity. The subjects were divided into 2 groups, with 18 being given a 5% potassium nitrate dentifrice (treated group) and the other 18 a vehicle paste (control group). Both groups were instructed to brush their teeth 2 × a day. The hypersensitivity levels of the affected teeth were assessed by 2 stimuli, one tactile and the other cold air, and by the perception of pain. The results of all 3 assessment methods indicated that the potassium nitrate dentifrice significantly decreased the level of hypersensitivity at weeks 4, 8, and 12. In the treated group, a rapid decrease of positive scores for both the cold air stimulus and the subjective symptoms appeared from week 2. Although a significant decrease of the assessment score was also observed in the control group, the reduction rate of the score was much greater in the treated group by ail 3 assessment methods at weeks 4, 8, and 12. Complete relief of subjective symptoms throughout the 12 weeks’examination was noted in 67% of the subjects in the treated group, but in only 6% in the control group. These results suggest the usefulness of a 5% potassium nitrate dentifrice in Japanese patients with dentinal hypersensitivity. 相似文献
46.
Hiroyuki Yamashita MD Katsuhiko Kawakami Eiichirou Murakami Syoji Kuroki 《Surgery today》1990,20(2):229-233
A rare case of primary linitis plastica carcinoma of the colon seen in a 44 year old Japanese man is described herein. The
patient had a complete obstruction of the descending colon and was treated with a loop colostomy followed shortly afterward
by a left hemicolectomy. At the time of the second operation, the entire thickness of the colonic wall was found to be infiltrated
by cancer cells, however, the other intraabdominal organs were free of cancerous involvement. The histopathological diagnosis
made at this time was primary linitis plastica carcinoma of the descending colon. Nine months later, the patient developed
an intestinal obstruction and relaparotomy revealed diffuse peritoneal dissemination. Two years after the first operation,
upper GI films and a gastrofiberscopic examination revealed gastric involvement. The patient died 28 months after his initial
operation, and autopsy revealed widespread metastases in the peritoneal surface, paraaortic lymph nodes, small intestine,
remaining colon and stomach. 相似文献
47.
Yuko Takeyama Keiki Ogino Hiroyuki Segawa Haruo Kobayashi Taizo Uda Tatsuya Houbara 《Basic & clinical pharmacology & toxicology》1995,76(1):50-55
Abstract: The effects of zinc on the production of active oxygen species were investigated in rat neutrophils by chemilumi-nescence and spectrophotometric assays. The luminol-dependent chemiluminescence in unstimulated neutrophils showed a single peak. Zinc at concentrations lower than 0.1 mM augmented the intensity of chemiluminescence and showed a bimodal pattern, the first peak of which was inhibited by superoxide dismutase and catalase, while the second peak disappeared in the presence of catalase, but was unaffected by superoxide dismutase. At the same concentrations of zinc, O2? and H2O2 production increased, but secretion and activity of myeloperoxidase were not affected. Zinc at 0.1 mM enhanced the second peak of luminol-dependent chemiluminescence, and concomitantly O2? and H2O2 production of neutrophils stimulated with formyl-methionyl-leucyl-phenylalanine. Homogenized neutrophils showed a bimodal pattern on induction by zinc, the second peak of which was inhibited slightly by catalase and completely by sodium azide, but was not inhibited by superoxide dismutase. Zinc-induced O2? production was inhibited by pertussis toxin, but was not significantly inhibited by a protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), or a calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7). These results suggest that zinc can augment luminol-dependent chemiluminescence by increasing O2? production through the classical signal transduction pathway, and by increasing H2O2 not via O2?. 相似文献
48.
Effects of calmodulin antagonists on calcium-activated potassium channels in pregnant rat myometrium. 总被引:2,自引:1,他引:1 下载免费PDF全文
1. The effects of W-7, trifluoperazine, and W-5 on Ca2(+)-activated K(+)-channels were investigated with the inside-out patch-clamp method in smooth muscle cells freshly dispersed from pregnant rat myometrium. These drugs are known to have different potencies as calmodulin antagonists. 2. In the presence of 1 microM Ca2+ on the cytoplasmic side ([Ca2+]i), the fraction of time the channel was open (open probability, Po) was about 0.9 and the calmodulin antagonists (1-30 microM) applied to the cytoplasmic face reduced Po to 0.65-0.55 dose-dependently. In the presence of 0.1-0.16 microM Ca2+, when Po was very low (0.02), calmodulin antagonists increased Po. All antagonists used produced almost identical effects at the same concentration. 3. The probability density function of the open time distribution could be described by the sum of two exponentials. W-7 decreased the time constant of slow component of distribution and at 30 microM the slow component disappeared both at 1 and 0.25 microM [Ca2+]i, reflecting the appearance of flickering channel activity. The probability density function of the closed time distribution could be fitted with three exponentials. The time constants of these components were not significantly altered by W-7. 4. Internally applied calmodulin (1-5 microM) did not produce any significant effect on channel activity. 5. The effects of calmodulin antagonists are considered to be due to a direct action of these compounds on the channel, and suggest that channel activation by Ca2+ is not mediated by calmodulin. 相似文献
49.
Kentaro Yamashita Hiroyuki Tsukuda Yasuyo Mizukami Jun Ito Shigeo Ikuta Yoshihiro Kondo Hiroshi Kinoshita Yasunori Fujisawa Kohzoh Imai 《Journal of gastroenterology》1997,32(5):684-688
A case of hepatic infarction with portal thrombosis is reported. A 63-year-old woman with liver cirrhosis and esophageal varices
was admitted for treatment of the esophagel varices. Endoscopic variceal ligation (EVL) and endoscopic injection sclerotherapy
(EIS) were performed. Two months later, she experienced right hypochondralgia and right flank pain. Serum transaminase levels
were suddenly elevated, and computed tomography scans of the liver showed multiple small nodular lesions. Her condition worsened,
and she died of hepatic failure. Autopsy revealed splenic and portal vein thrombosis, multiple hepatic infarction, and evidence
of chronic pancreatitis. We believe that liver cirrhosis and chronic pancreatitis were the main risk factors for the portal
thrombosis, and the treatment for esophageal varices appeared to have triggered the thrombosis. The hepatic infarction was
caused by the portal thrombosis. 相似文献
50.
Tsutomu Saito Hiroyuki Horimi Tsuguo Hasegawa Toshiro Kamoshida 《Surgery today》1993,23(12):1081-1084
We report herein the case of a 42-year-old man in whom dyspnea on exertion was found to be caused by isolated tricuspid stenosis. Two-dimensional echocardiogram showed thickening of the tricuspid valve with a markedly enlarged right atrium. A color-flow Doppler examination-revealed severe tricuspid stenosis without regurgitation and a Doppler-derived tricuspid diastolic pressure gradient of 23 mmHg. At the time of surgery, the patient was noted to have a stenotic tricuspid valve with thickened leaflets, fused commissures, and almost normal chorda tendineae. The valve leaflets were teased apart to the scattered specimen, and tricuspid valve replacement was successfully performed. Microscopic examination of the specimen demonstrated infective endocarditis. Isolated acquired tricuspid stenosis is extremely rare and, to our knowledge, this is the first case of infective endocarditis being involved as the primary cause. 相似文献