全文获取类型
收费全文 | 12544篇 |
免费 | 690篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 146篇 |
儿科学 | 659篇 |
妇产科学 | 239篇 |
基础医学 | 1771篇 |
口腔科学 | 141篇 |
临床医学 | 871篇 |
内科学 | 2713篇 |
皮肤病学 | 369篇 |
神经病学 | 602篇 |
特种医学 | 545篇 |
外国民族医学 | 1篇 |
外科学 | 1269篇 |
综合类 | 490篇 |
一般理论 | 6篇 |
预防医学 | 825篇 |
眼科学 | 495篇 |
药学 | 1019篇 |
中国医学 | 88篇 |
肿瘤学 | 1046篇 |
出版年
2023年 | 75篇 |
2022年 | 211篇 |
2021年 | 354篇 |
2020年 | 151篇 |
2019年 | 216篇 |
2018年 | 289篇 |
2017年 | 213篇 |
2016年 | 266篇 |
2015年 | 302篇 |
2014年 | 408篇 |
2013年 | 554篇 |
2012年 | 673篇 |
2011年 | 727篇 |
2010年 | 454篇 |
2009年 | 404篇 |
2008年 | 551篇 |
2007年 | 637篇 |
2006年 | 584篇 |
2005年 | 516篇 |
2004年 | 455篇 |
2003年 | 409篇 |
2002年 | 394篇 |
2001年 | 318篇 |
2000年 | 297篇 |
1999年 | 248篇 |
1998年 | 175篇 |
1997年 | 143篇 |
1996年 | 145篇 |
1995年 | 107篇 |
1994年 | 111篇 |
1993年 | 100篇 |
1992年 | 168篇 |
1991年 | 160篇 |
1990年 | 148篇 |
1989年 | 173篇 |
1988年 | 197篇 |
1987年 | 153篇 |
1986年 | 149篇 |
1985年 | 148篇 |
1984年 | 126篇 |
1983年 | 79篇 |
1982年 | 70篇 |
1979年 | 90篇 |
1978年 | 82篇 |
1977年 | 70篇 |
1976年 | 71篇 |
1974年 | 66篇 |
1973年 | 82篇 |
1971年 | 66篇 |
1970年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
45.
Mercury ingested from dietary sources has potent neurotoxic and teratogenic effects. Initial studies have shown that mercury may also affect fetal lung development. Since these pulmonary effects may play a role in subsequent neonatal morbidity and mortality due to compromising of the development of the lung, mercury effects in fetal and neonatal lung were investigated. Methylmercuric chloride (MMC), 1,000 ppm (15 mg/kg of body weight), was administered via an intragastric tube to timed-pregnant Swiss/Webster mice on day 9 of gestation. Lungs from fetuses on gestational day 18 and from neonates on days 1, 5, or 10 after birth were studied. Significant changes in MMC-exposed lungs compared to controls occurred at postnatal day 1. At this time, lung weight per gram body weight increased, phospholipid content per gram of lung or per microgram of DNA decreased, while DNA per gram of lung increased. Methylmercury appears to have delayed lung maturation. Cuboidal epithelial cells in alveolar tubules contained conspicuous glycogen deposits, and differentiation of alveolar type II cells was adversely affected. These results suggest that prenatal exposure to methylmercury may be detrimental to lung development, specifically to the initiation of surfactant synthesis, by delaying the normal pattern of maturation of the alveolar type II cells within the lungs. Pediatr Pulmonol. 1994; 17:11–21 . © 1994 Wiley-Liss. Inc. 相似文献
46.
E Melissari G Monte V S Lindo K D Pemberton N V Wilson R Edmondson S Das V V Kakkar 《Blood coagulation & fibrinolysis》1992,3(6):749-758
During a 3-year period we studied 393 adult patients (382 of whom were unrelated) with a history of acute venous thromboembolism. A congenital deficiency state known to predispose to thrombosis was found in 27.2%. Of these, most were due to deficiencies of protein C (9.2%), protein S (7.6%), antithrombin III (5%) or to increased plasma PAI-1 concentration (3.1%) which, in the absence of any known factor that predisposes towards thrombosis, results in a diminished fibrinolytic activity. There was a characteristic pattern between the age of onset (mean 34 years) of thrombosis and individual protein deficiency. Thrombosis appeared spontaneously in 73% of cases with recurrence in 80%. In contrast, in the remaining unrelated patients, 138 (35.1%) in whom venous thromboembolism was secondary and occurred at a mean age of 43 years, and in the other 140 (35.6%) who suffered thromboembolism spontaneously at a later age (mean age 55), there was no permanent protein deficiency state or alteration in fibrinolytic activity and thrombosis recurrence was lower (53.6% and 20.7% respectively). Of the 393 patients, deep vein thrombosis was the most common manifestation; however, in congenital thrombophilia, thrombosis of visceral vessels and Raynaud's syndrome (6%) were also detected. 相似文献
47.
Five female patients and one male patient with solid and papillary epithelial neoplasms of the pancreas were examined with computed tomography (CT). The mean age of the patients was 27 years (range, 13-46 years). All cases showed well-encapsulated, round or lobulated masses consisting of both cystic and solid areas. Cystic portions showed CT numbers that suggested hemorrhagic necrosis. There were no internal septations within the masses. In three tumors located in the head of the pancreas, dilatation of the biliary tree was absent or minimal, although the masses were large. Two tumors contained calcifications. One tumor demonstrated metastatic deposits in liver and lymph nodes. Metastatic masses appeared similar to the primary pancreatic mass. Solid and papillary neoplasm of the pancreas should be the primary diagnostic consideration when characteristic CT findings are detected in a young female patient. 相似文献
48.
A comparative pharmacokinetic study of a new controlled release multiple unit propranolol formulation and a conventional propranolol tablet was carried out in twelve healthy human volunteers in a randomized balanced crossover design. Under a single dosage regimen, subjects were administered either a single capsule containing controlled release propranolol equivalent to 160 mg of the drug or 80 mg of conventional propranolol tablet, twelve hourly. Peak plasma propranolol concentrations were low which occurred later after controlled release administration than after the administration of the conventional tablet. Analysis of the area under the plasma concentration-time curve (AUC) for the two formulations indicate no significant difference of bioavailability despite a prolonged absorption time and maintenance of effective plasma concentration for the controlled release preparation. 相似文献
49.
Advanced primary breast cancer: assessment at mammography of response to induction chemotherapy 总被引:2,自引:0,他引:2
The response to induction chemotherapy is an important prognostic factor in patients with nonmetastatic, locally advanced breast carcinomas. Assessment at mammography of the response of 60 breast cancers in 59 women was performed between 1974 and 1986. Responses were excellent in 13 tumors, moderate in 34, and poor in 13 (excellent moderate = 78%). Assessment of response of discrete masses in a fatty breast was easiest; assessment of response of tumor areas that were poorly defined-such as a focal area of architectural distortion or mass in dense breast parenchyma-was more difficult. Of 17 patients with excellent pathologic responses-that is, minimal or no residual tumor-15 (88%) had complete responses (no residual tumor) as determined with mammography, physical examination, or both. Mammography provides information complementary to physical examination and is essential in the accurate assessment of the response to chemotherapy of locally advanced breast cancer. 相似文献
50.