全文获取类型
收费全文 | 488篇 |
免费 | 20篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 14篇 |
妇产科学 | 8篇 |
基础医学 | 48篇 |
口腔科学 | 5篇 |
临床医学 | 50篇 |
内科学 | 155篇 |
皮肤病学 | 11篇 |
神经病学 | 13篇 |
特种医学 | 89篇 |
外科学 | 34篇 |
综合类 | 22篇 |
预防医学 | 20篇 |
眼科学 | 12篇 |
药学 | 40篇 |
中国医学 | 4篇 |
肿瘤学 | 14篇 |
出版年
2023年 | 7篇 |
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 4篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 15篇 |
2014年 | 11篇 |
2013年 | 16篇 |
2012年 | 34篇 |
2011年 | 23篇 |
2010年 | 16篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 27篇 |
2006年 | 16篇 |
2005年 | 22篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 15篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 13篇 |
1993年 | 12篇 |
1992年 | 4篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1939年 | 1篇 |
排序方式: 共有540条查询结果,搜索用时 0 毫秒
1.
Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant. 相似文献
2.
Image-directed percutaneous biopsies with a biopsy gun 总被引:3,自引:0,他引:3
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method. 相似文献
3.
Task-specific neural activity in the primate prefrontal cortex 总被引:12,自引:0,他引:12
Real-world behavior is typically more complicated than a one-to-one mapping between a stimulus and response; the same stimulus can lead to different behaviors depending on the situation, or the same behavior may be cued by different stimuli. In such cases, knowledge of the formal demands of the task at hand is required. We found that in monkeys trained to alternate between three tasks, the activity of many neurons in the prefrontal cortex was task dependent. This included changes in overall firing rate, in firing-rate profiles (shape of responses over time), and in stimulus and response selectivity. These findings support the hypothesis that a major prefrontal function is the acquisition and implementation of task context and the "rules" used to guide behavior. 相似文献
4.
颅内蛛网膜囊肿34例 总被引:1,自引:1,他引:0
1 临床资料1.1 一般资料 1986 / 1997收治颅内蛛网膜囊肿 34(男 2 8,女 6 )例 .年龄 3~ 6 8岁 ,其中 16岁以下 17例 .有头部外伤史者 15例 ,无明显诱因者 19例 .病程 :2 m o~ 14a.头部外伤至发病时间 :7d~ 2 a. 34例中幕上 30例 ,幕下 4例 ,其中侧裂池 15例 .1.2 临床症状 表现头疼、头昏或伴呕吐、视力下降、视乳头水肿等颅内压增高的症状 18例 ,癫痫发作 7例 ,偏瘫 6例 ,行走不稳 2例 ,失语 1例 .1.3 辅助检查 本组 2 8例作 CT检查 ,6例行 MRI检查证实 .头颅 CT扫描特征 :脑实质外有一边界清楚的低密度病灶 ,CT值与脑脊液… 相似文献
5.
Trippodo NC Fox M Monticello TM Panchal BC Asaad MM 《Journal of cardiovascular pharmacology》1999,34(6):782-790
Vasopeptidase inhibitors are single molecules that inhibit neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) simultaneously. Omapatrilat, the first in this new class of cardiovascular agents, potentiates vasodilatory and cardioprotective peptides and represses angiotensin II. This study compared the effects of omapatrilat with those of a pure ACE inhibitor on cardiac geometry and survival in animals with heart failure. BIO TO-2 cardiomyopathic hamsters (CMHs) in the early stages of dilated heart failure were treated with vehicle or maximal ACE inhibitory doses of captopril (750 micromol/kg/day) or omapatrilat (200 micromol/kg/day). Prolonged vasopeptidase inhibition increased median survival time after the start of treatment by 99 and 31% compared with vehicle and captopril, respectively (median survival times: 146, 221, and 290 days with vehicle, captopril, and omapatrilat, respectively; p < 0.001 for all comparisons). In similar CMHs, captopril or omapatrilat administered for 2 months significantly (p < 0.05) decreased heart weight, pulmonary congestion (lung weight), and left ventricular (LV) chamber volume compared with vehicle. Omapatrilat significantly increased LV mass-to-volume ratio compared with vehicle and captopril. Omapatrilat, but not captopril, significantly increased urinary atrial natriuretic peptide excretion, indicating NEP inhibition. Thus vasopeptidase inhibition with omapatrilat was more effective than ACE inhibition with captopril in preventing changes in LV geometry and premature mortality in hamsters with dilated heart failure. 相似文献
6.
The ethereal extract of AJUGA IVA (L.) S CHREB. roots, yielded 4 ecdysones. Three were proved to be cyasterone, makisterone A and ecdysterone, by using UV, IR, MS spectral methods and comparison with standard samples. Spectral data indicate that the fourth ecdysone is similar to cyasterone but having an additional hydroxy group in the side-chain. The chromatographic pattern of ecdysone content in roots, stems and leaves is presented as well as a rapid and simple Semiquantitative method for their estimation. The roots had the highest total content (0.381%). 相似文献
7.
WF Paterson E McNeill S Reid AS Hollman MD Donaldson 《Archives of disease in childhood》1998,79(4):323-327
OBJECTIVE: To assess the efficacy of a longer acting preparation of the gonadotrophin releasing hormone (GnRH) analogue goserelin (Zoladex LA, 10.8 mg) in 12 girls with central precocious or early puberty. METHODS: Two girls started treatment de novo; the remainder had been on suppressive treatment for a median duration of 1.5 (range, 0.2-5.6) years. Assessment comprising auxology, pubertal staging, and pelvic ultrasound examination was carried out at weeks 0, 4, 8, 10, and 12 (first cycle) and weeks 8, 10, and 12 (second cycle) to evaluate the required injection frequency. Thereafter, assessment was performed on the day of injection. Zoladex LA was given every 12 weeks unless pubertal progression occurred. RESULTS: Satisfactory control was achieved in eight patients using this regimen, and three patients required more frequent injections. One girl was removed from the study because of clinical progression and extreme mood swings. No serious adverse effects occurred. Mean height velocity during the study period was 4.5 cm/year (range, 3.1-6.6) compared with 6.5 cm/year (range, 3.8-9.6) before treatment in nine patients for whom data were available. CONCLUSIONS: Zoladex LA was effective in controlling precocious puberty in girls when given at intervals of 9-12 weeks and it is recommended that an initial assessment is made eight weeks after beginning treatment. 相似文献
8.
Kamel Sadat M.D. Hari Prakash Diddi M.B.B.S. Berthold Klas B.S. Ayman Haj Asaad M.D. Elif İjlal Çekirdekçi M.D. Aylin Sungur M.D. Selvin Sudhakar M.D. Matthew Cain M.D. Arshad Kamal M.D. Navin C. Nanda M.D. 《Echocardiography (Mount Kisco, N.Y.)》2013,30(10):1227-1231
Hypertrophic cardiomyopathy (HCM) is the most common genetically transmitted cardiomyopathy. In patients resistant to medical management, myectomy is the surgical procedure of choice to reduce the symptoms of left ventricular outflow obstruction. Two‐dimensional transesophageal echocardiography (2DTEE) has become part of the operative procedure by decreasing the incidence of postoperative complications. However, because of the three‐dimensional geometry of left ventricular outflow tract, it is unable to comprehensively assess the location and severity of the obstruction and to provide accurate guidance during myectomy. In this study, 10 patients with HCM underwent live/real time three‐dimensional transesophageal echocardiography (3DTEE) intra‐operatively to measure the volume of the resected septum. This volume correlated well with the volume of the resected septal muscle directly obtained using a graduating cylinder containing water (r = 0.9, P < 0.000). 3DTEE may be potentially used as an adjunct to guide the surgeon in performing an adequate myectomy with a lower incidence of residual obstruction and complications such as an iatrogenic ventricular septal defect. 相似文献
9.