全文获取类型
收费全文 | 128843篇 |
免费 | 11261篇 |
国内免费 | 6629篇 |
专业分类
耳鼻咽喉 | 1224篇 |
儿科学 | 1958篇 |
妇产科学 | 2930篇 |
基础医学 | 13463篇 |
口腔科学 | 2677篇 |
临床医学 | 15982篇 |
内科学 | 20153篇 |
皮肤病学 | 1590篇 |
神经病学 | 6396篇 |
特种医学 | 4195篇 |
外国民族医学 | 40篇 |
外科学 | 13339篇 |
综合类 | 19310篇 |
现状与发展 | 20篇 |
一般理论 | 18篇 |
预防医学 | 9432篇 |
眼科学 | 3446篇 |
药学 | 13462篇 |
115篇 | |
中国医学 | 6562篇 |
肿瘤学 | 10421篇 |
出版年
2024年 | 347篇 |
2023年 | 1716篇 |
2022年 | 4018篇 |
2021年 | 5453篇 |
2020年 | 4056篇 |
2019年 | 3704篇 |
2018年 | 3940篇 |
2017年 | 3705篇 |
2016年 | 3308篇 |
2015年 | 5235篇 |
2014年 | 6733篇 |
2013年 | 6945篇 |
2012年 | 10126篇 |
2011年 | 10871篇 |
2010年 | 7481篇 |
2009年 | 6150篇 |
2008年 | 7783篇 |
2007年 | 7726篇 |
2006年 | 7318篇 |
2005年 | 6689篇 |
2004年 | 4839篇 |
2003年 | 4400篇 |
2002年 | 3650篇 |
2001年 | 3090篇 |
2000年 | 2846篇 |
1999年 | 2643篇 |
1998年 | 1311篇 |
1997年 | 1220篇 |
1996年 | 986篇 |
1995年 | 948篇 |
1994年 | 885篇 |
1993年 | 504篇 |
1992年 | 889篇 |
1991年 | 801篇 |
1990年 | 668篇 |
1989年 | 569篇 |
1988年 | 525篇 |
1987年 | 450篇 |
1986年 | 357篇 |
1985年 | 284篇 |
1984年 | 184篇 |
1983年 | 167篇 |
1982年 | 95篇 |
1981年 | 93篇 |
1979年 | 140篇 |
1978年 | 111篇 |
1977年 | 83篇 |
1974年 | 94篇 |
1973年 | 72篇 |
1972年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
本文对SOD的紫外分光光度法测定进行了实用性研究。结果表明,本文方法具有用血量少,重现性好,快速、灵敏,试剂廉价等优点。西宁地区与平原地区人群的比较测定显示,前者SOD活性明显高于后者(P<0.01)。 相似文献
52.
53.
A Coagulation Factor IX-Deficient Mouse Model for Human Hemophilia B 总被引:25,自引:10,他引:15
Lin Hui-Feng; Maeda Nobuyo; Smithies Oliver; Straight David L.; Stafford Darrel W. 《Blood》1997,90(10):3962-3966
54.
临床输液监控系统的设计 总被引:5,自引:0,他引:5
本文针对临床输液过程中出现的漏、停、输液速度改变等各种问题,讨论了一由单台微机和多个单片机通讯实现的多床输液自动监控、自动反应、自动报答系统的可行性,并给出了主要部分的硬件、软件设计方法。 相似文献
55.
Propionic acidemia is a rare hereditary disease which is an autosomal recessive disorder. Defect of propionyl CoA carboxylase results in abnormal accumulation of propionate and its metabolites which interfere the pathway of glycine cleavage and the urea cycle. This organic acidemia is characterized by a wide spectrum of clinical and biochemical findings, including recurrent vomiting, difficult feeding, lethargy, hypotonia, metabolic ketoacidosis, hyperglycinemia and hyperammonemia during the acute episodes. We present a male newborn infant who sustained this disorder and was managed successfully with blood exchange transfusion, peritoneal dialysis, supplemented with sodium benzoate and sodium bicarbonate therapy. Urine gas chromatography disclosed significant elevation of propionate and its metabolites which subsided 2 days after peritoneal dialysis. Special designed formula was then given with restriction of protein intake and supplement with sodium benzoate and sodium carbonate. Prenatal genetic counseling is necessary in further pregnancy. Diagnosis can be obtained when propionyl CoA carboxylase activity is low in cultured amniotic fluid cells or chorion villi sample or when there is abnormally high methylcitrate level in amniotic fluid. 相似文献
56.
林尚泽 《中华耳鼻咽喉头颈外科杂志》1994,(4)
报道1例严重鼻衄伴高血压、动脉硬化患者,经常规方法止血无效,行患侧颌内动脉超选择性栓塞术。术后鼻出血停止,但出现脑梗塞、昏迷,经抢救无效,于术后第9天死亡。认为对有动脉硬化的患者,应不用或慎用超选择性动脉栓塞术。 相似文献
57.
The authors compared the inhaled methacholine and exercise responses in 22 stable unmedicated asthmatic patients. The exercise and methacholine challenges were performed at one to three week intervals. Bronchial responsiveness to methacholine was measured in relation to the concentration of methacholine (PC20M). The response to exercise was expressed as the percentage of fall in FEV1, from the pre-exercise FEV1 The findings showed that 21 of 22 subjects demonstrated a fall in FEV1, of more than 20% after methacholine challenge, while only 9/22 subjects experienced a similar decrease in FEV1. All 9 of these positive response exercise cases completed three consecutive exercise challenges prior to the methacholine challenge. Of these cases, five were refractory to the repeated exercise challenge, and the PD20M at the nonexercise stage was significantly lower than the postexercise state. In fact, the methacholine challenge sensitivity actually decreased (PD20 increased) after repeated exercise. The authors concluded that methacholine seems to be a more sensitive bronchial provocation test than exercise. Second, only 55.6% of the exercise test-positive subjects were refractory to the second exercise challenge. Therefore, other factors besides the release of mediators should be considered in exercise induced asthma. Third, methacholine sensitivity actually decreased (PD20 increases) after repeat exercise challenge. 相似文献
58.
城市公共厕所发展趋势的探讨 总被引:1,自引:1,他引:0
介绍了改革开放以来各地出现的一些新型公厕,认为前店后厕、附属式公厕、生态公厕是发展趋势,而豪华型公厕的推广目前尚不具备条件. 相似文献
59.
Using the polymerase chain reaction (PCR)-based single strand conformation polymorphism (SSCP) analysis, we have examined the highly conserved regions of the p53 gene in 58 biopsy samples of head and neck tumors. Mutations were found in 13/58 (23%) tumor specimens, but not in 6 normal tissues. Ten of 13 mutations were due to single base changes and the remaining 3 were 1- or 8-base deletion mutants. These mutations were clustered in exons 5 and 7 and resulted in amino acid changes. Our results seem to indicate that mutations in the p53 gene contribute to a significant number of cases of the head and neck tumors including 20% of nasopharyngeal carcinoma biopsies. The relationship of Epstein-Barr virus or human papillomavirus and p53 gene mutations in this group of cancers was also analyzed and discussed. 相似文献
60.
Shigeharu Kimura Yoshimi Ohshige Liping Lin Tadashi Okumura Chizuko Yanaihara Noboru Yanaihara† Yahe Shiotani 《Journal of neuroendocrinology》1994,6(5):503-507
The localization of pituitary adenylate cyclase-activating polypeptide (PACAP) in the hypothalamus-pituitary system in rats was examined in light and electron microscopic immunocytochemistry using a specific antiserum to synthetic PACAP 1–38 (R0831). In light microscopic study, intensely PACAP-immunostained perikarya were observed in the supraoptic and paraventricular magnocellular nucleus in the hypothalamus. In the median eminence, many immunoreactive nerve fibers were observed in the internal layer, but a few immunoreactive terminals were noticed in the external layer. In the pituitary gland, numerous immunoreactive nerve fibers were observed in the posterior lobe. In the intermediate lobe, moderately immunostained cells were observed, but in the anterior lobe no immunostained cells were noticed. In electron microscopic study, PACAP-immunoreactivity was examined by avidin-biotin peroxidase complex method. In the perikarya of the supraoptic and paraventricular magnocellular nucleus, DAB-reaction products were distributed diffusely in the cytoplasmic matrix, frequently attaching to the rough-surfaced endoplasmic reticulum. In the nerve terminals of the posterior lobe, reaction products were observed among the secretory granules, but sometimes upon them. In the cells of the intermediate lobe, reaction products were also distributed in the cytoplasmic matrix. 相似文献