全文获取类型
收费全文 | 5610篇 |
免费 | 301篇 |
国内免费 | 58篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 169篇 |
妇产科学 | 67篇 |
基础医学 | 679篇 |
口腔科学 | 156篇 |
临床医学 | 403篇 |
内科学 | 1657篇 |
皮肤病学 | 88篇 |
神经病学 | 406篇 |
特种医学 | 265篇 |
外科学 | 914篇 |
综合类 | 33篇 |
一般理论 | 1篇 |
预防医学 | 176篇 |
眼科学 | 77篇 |
药学 | 308篇 |
中国医学 | 8篇 |
肿瘤学 | 508篇 |
出版年
2023年 | 47篇 |
2022年 | 99篇 |
2021年 | 193篇 |
2020年 | 95篇 |
2019年 | 132篇 |
2018年 | 137篇 |
2017年 | 110篇 |
2016年 | 130篇 |
2015年 | 152篇 |
2014年 | 161篇 |
2013年 | 211篇 |
2012年 | 322篇 |
2011年 | 328篇 |
2010年 | 177篇 |
2009年 | 187篇 |
2008年 | 294篇 |
2007年 | 321篇 |
2006年 | 264篇 |
2005年 | 266篇 |
2004年 | 226篇 |
2003年 | 207篇 |
2002年 | 226篇 |
2001年 | 124篇 |
2000年 | 128篇 |
1999年 | 121篇 |
1998年 | 81篇 |
1997年 | 37篇 |
1996年 | 49篇 |
1995年 | 41篇 |
1994年 | 31篇 |
1993年 | 35篇 |
1992年 | 87篇 |
1991年 | 82篇 |
1990年 | 83篇 |
1989年 | 70篇 |
1988年 | 65篇 |
1987年 | 72篇 |
1986年 | 71篇 |
1985年 | 64篇 |
1984年 | 50篇 |
1983年 | 36篇 |
1982年 | 19篇 |
1979年 | 49篇 |
1977年 | 28篇 |
1975年 | 26篇 |
1974年 | 27篇 |
1973年 | 20篇 |
1972年 | 23篇 |
1971年 | 21篇 |
1969年 | 18篇 |
排序方式: 共有5969条查询结果,搜索用时 15 毫秒
71.
Akiyoshi Kashii Susumu Mitani Y. Kasai M. Mito Takashi Suzuki Toshiya Ito Ryoichi Tsuchiya A. Kaneto K. Tanikawa Masanobu Ishida Tsuyoshi Miura Shiro Hayashi Hiroshi Sano Keisuke Yoshida Hiroshi Ito Nobuo Okazaki Nobu Hattori Ichio Honjo Yasuo Kuroyanagi 《Journal of gastroenterology》1973,8(4):393-401
72.
Dr. Masao Arai MD Maki Niioka BS Katsuya Maruyama MD Norihito Wada MD Noboru Fujimoto PhD Tetsu Nomiyama MD Shoutarou Tanaka MD Isao Okazaki MD 《Digestive diseases and sciences》1996,41(5):995-1000
We treated 18 patients with chronic hepatitis C by recombinant interferon-α (6 MIU for 24 weeks). In seven patients, serum aminotransferase levels declined to normal (responders). To evaluate the effect of interferon on matrix metalloproteinases (MMPs) and their inhibitors, namely tissue inhibitors of metalloproteinases (TIMPs), the serum levels of these enzymes were determined by enzyme immunoassay (EIA) using a specific monoclonal antibody. In responders, there was a tendency, but not a significant one, towards either an increase in serum MMP 1 levels or a decrease in serum TIMP 1 levels. In contrast, in nonresponders, both a significant decrease in MMP 1 and MMP 3 and a significant increase in TIMP 1 were observed. The number of cases of either increase in serum MMP levels or decrease in serum TIMP levels was significantly larger in responders than in nonresponders. Furthermore, the ratio of MMP 1 to TIMP 1 significantly increased in responders, suggesting that the balance between matrix formation and degradation in hepatic fibrosis tended to move toward degradation. These data indicate that interferon may exert a beneficial effect on hepatic fibrosis in parallel with improvement of aminotransferase activity. 相似文献
73.
Hasegawa T Ishihara K Takakura S Fujii H Nishimura T Okazaki M Katakami N Umeda B 《Internal medicine (Tokyo, Japan)》2000,39(10):794-797
OBJECTIVE: To determine an appropriate duration for a short course of oral steroids in cases of asthma exacerbations. SETTING: A 1,000 bed city hospital in Kobe, Japan. PATIENTS: Patients with asthma exacerbations who needed hospital admission. METHODS: Following an initial treatment with a 3-day course of intravenous methylprednisolone, patients were allocated to either a 1-week (1 W) or a 2-week (2 W) course of oral prednisolone (PSL, 0.5 mg/kg). OUTCOME MEASURES: Peak expiratory flow rate (PEF) and rate of unscheduled hospital visits and readmission. RESULTS: Twenty patients were enrolled (10 in 1 W, 10 in 2 W). Mean PEF just before starting oral PSL in 1 W and 2 W were 51 and 58% of each patient's best value. PEF was significantly improved and to a similar degree over the course of time in both 1 W and 2 W. The frequency of unexpected hospital visits during a 3-month period after discharge was similar (2 in 1 W and 2 in 2 W). No readmission occurred during the same period. CONCLUSIONS: Because both the 1-week and the 2-week course of oral PSL were equally effective in the treatment of asthma exacerbations, 1 week may be appropriate as the maximum duration of a short rescue course of oral steroids. 相似文献
74.
75.
Takata Noriko Miyagawa Masao Matsuda Takuya Takakado Masahiro Okada Tomohisa Kawaguchi Naoto Makita Kenji Ishikawa Hirofumi Tsuruoka Shintaro Uwatsu Kotaro Kido Teruhito 《Annals of nuclear medicine》2021,35(9):1015-1021
Annals of Nuclear Medicine - Albumin–globulin ratio (AGR), which is calculated by dividing serum albumin by serum globulin, is considered as a cancer-related inflammation biomarker. Although... 相似文献
76.
77.
78.
T. Matsushige Y. Akiyama T. Okazaki K. Shinagawa N. Ichinose K. Awai K. Kurisu 《AJNR. American journal of neuroradiology》2015,36(8):1507
BACKGROUND AND PURPOSE:Inflammation and degeneration of the intracranial saccular aneurysm wall play a major role in aneurysm formation, development and subsequent rupture. The aim of this study was to characterize the walls of unruptured intracranial aneurysms by using a hybrid of opposite-contrast MRA at 3T.MATERIALS AND METHODS:Fourteen consecutive patients with 17 unruptured intracranial aneurysms who initially underwent clipping surgery were prospectively evaluated. All aneurysms were scanned preoperatively by using a hybrid of opposite-contrast MRA in 3T high-resolution MR imaging. We classified intraoperative findings of atherosclerotic plaques in the aneurysms into 3 grades: grade A (major plaques), grade B (minor plaques), and grade C (no plaques). The contrast ratio of the high-intensity area was also measured relative to the background low-intensity area inside the carotid artery.RESULTS:Findings from preoperative plaque imaging of the aneurysm corresponded to the intraoperative findings in 15 of 16 aneurysms (excluding 1 that was impossible to visualize in its entirety due to anatomic reasons). Overall sensitivity and specificity of the hybrid of opposite-contrast MRA were 88.9% and 100%, respectively. During the operation, 4 aneurysms were classified as grade A; 5, as grade B; and 7, as grade C. The means of the contrast ratio for grades A, B, and C were 0.72 ± 0.03, 0.34 ± 0.30, and −0.02 ± 0.09, respectively.CONCLUSIONS:The hybrid of opposite-contrast MRA can detect visible atherosclerotic plaques in the unruptured aneurysm wall, and the contrast ratio in intracranial aneurysms correlated with their presence and extent. A study including a larger series is needed to validate the diagnostic potential of this imaging technique.Intracranial aneurysms are common vascular lesions, often consisting of a saccular dilation of a cerebral artery vessel. The prevalence of intracranial aneurysms in the general population is estimated between 2.5% and 5%.1,2 Aneurysmal rupture occurs with a 1% risk per year, depending on the size, location, and morphometry of the aneurysm, and leads to subarachnoid hemorrhage with associated high morbidity and mortality rates.1,2 Intracranial aneurysms with an estimated high risk of rupture undergo management via a surgical or endovascular approach, depending on the specific risks of treatment.3,4 Therefore, it is important to accurately assess the risk of aneurysmal rupture.The pathogenesis of intracranial aneurysms and their natural history are not well-understood. Histopathologic studies have shown that the infiltration of inflammatory cells and the degeneration of the aneurysm wall with atherosclerosis correlates with the formation, development, and rupture risk of cerebral aneurysms.5–9 However, characterization of the aneurysm wall is limited by imaging data quality and the need to harvest surgical specimens.In this regard, the characteristics of high-field-strength MR imaging, which has a favorable SNR and changes in relaxation time and susceptibility, can depict the intracranial vessel walls and their pathologies, including small vessels with atherosclerosis.10,11The hybrid of opposite-contrast MR angiography (HOP-MRA) used in this study is a modern technique that combines the advantages of 3D TOF MRA and flow-sensitive black-blood (FSBB) MRA.12 The clinical efficacy of this technique was established to improve the visualization of peripheral vessels.13,14 Theoretically, tissue with shorter T1 and T2* introduces high signal in FSBB of HOP-MRA, which demonstrates atherosclerotic plaques, including fat, as high-signal-intensity areas and demonstrates the blood space as low-signal-intensity areas in intracranial aneurysms.12 The strength of this technique is the dual-echo 3D gradient-echo sequence, which enables a shorter imaging time and minimization of misregistration. The present study investigated the utility of HOP-MRA at 3T for the characterization of visible atherosclerotic plaques in intracranial aneurysms by using subtraction between TOF and FSBB imaging. 相似文献
79.
80.
Association between parents' trust in mental health professionals and disengagement from psychiatric service within the first 6 months of initial treatment of schizophrenia 下载免费PDF全文