全文获取类型
收费全文 | 1045篇 |
免费 | 62篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 43篇 |
妇产科学 | 7篇 |
基础医学 | 109篇 |
口腔科学 | 32篇 |
临床医学 | 107篇 |
内科学 | 262篇 |
皮肤病学 | 16篇 |
神经病学 | 40篇 |
特种医学 | 211篇 |
外科学 | 64篇 |
综合类 | 18篇 |
预防医学 | 78篇 |
眼科学 | 7篇 |
药学 | 53篇 |
中国医学 | 4篇 |
肿瘤学 | 71篇 |
出版年
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 20篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 20篇 |
2014年 | 20篇 |
2013年 | 37篇 |
2012年 | 45篇 |
2011年 | 34篇 |
2010年 | 42篇 |
2009年 | 39篇 |
2008年 | 47篇 |
2007年 | 44篇 |
2006年 | 32篇 |
2005年 | 41篇 |
2004年 | 42篇 |
2003年 | 24篇 |
2002年 | 37篇 |
2001年 | 24篇 |
2000年 | 30篇 |
1999年 | 25篇 |
1998年 | 31篇 |
1997年 | 42篇 |
1996年 | 39篇 |
1995年 | 30篇 |
1994年 | 27篇 |
1993年 | 26篇 |
1992年 | 31篇 |
1991年 | 15篇 |
1990年 | 30篇 |
1989年 | 25篇 |
1988年 | 27篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 17篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1968年 | 2篇 |
1935年 | 2篇 |
排序方式: 共有1126条查询结果,搜索用时 15 毫秒
1.
2.
BACKGROUND. Studies have documented the potential contributions of preventive health care programs. Yet little is known about which screening tests should be included in public health programs for older persons. This study offers recommendations regarding these tests. METHODS. The recommendations come from synthesizing the findings of the US Preventive Services Task Force, the literature, and the consensus of experts in geriatrics, gerontology, and health policy research. The literature was evaluated to identify methodologically sound studies of the prevalence of selected disorders and benefits and availability of screening procedures for those disorders. Experts from various fields specializing in the care of the elderly formed panels to assist in evaluating the literature and providing further information from gerontological and public health perspectives. RESULTS. We recommend vision testing for refractive error; inspection of the skin surface for fungal infection and skin cancer, drug eruptions, and xerosis; a history for symptoms of xerosis; audiometric testing for presbycusis; surveys for hearing loss; otoscopic inspection for cerumen impaction; dental examination for caries; measurement of blood pressure for hypertension; and breast examination and mammography for cancer. CONCLUSIONS. Our study suggests that these screening procedures are useful for public health screening programs. More information is needed on the effects of screening services on the health and functioning of older persons. 相似文献
3.
M A Valentovic J G Ball D K Anestis K W Beers E Madan J L Hubbard G O Rankin 《Toxicology》1992,75(2):121-131
Aniline and its halogenated derivatives are widely used as chemical intermediates. The purpose of this study was to determine the hepatotoxic and nephrotoxic potential of the 2-haloanilines. Male Fischer 344 rats (n > or = 4) were injected (i.p.) with 1.0 or 1.25 mmol/kg of: aniline (A), 2-fluoroaniline (2-FA), 2-chloroaniline (2-ClA), 2-bromoaniline (2-BrA), 2-iodoaniline (2-IA) or vehicle (0.9% saline, 2.5 ml/kg). All compounds were injected as hydrochloride salts. Renal and hepatic function was monitored 24 h after treatment. All of the 2-haloanilines induced oliguria, diminished kidney weight, tubular casts and decreased renal cortical slice accumulation of organic anions. Blood urea nitrogen (BUN) levels were increased (P < 0.05) by treatment with 1.0 or 1.25 mmol/kg of 2-FA, 2-ClA or 2-BrA. Hepatic alterations were also observed and characterized by elevated plasma ALT/GPT activity and altered morphology in the centrilobular region. The nephrotoxic and hepatotoxic potentials were similar among the 2-haloanilines but aniline was less toxic than its 2-halo derivatives. These results demonstrated that halogen substitution at the 2-position of aniline increased hepatic and renal toxicity. However, the severity of toxicity was not influenced by the nature of the halogen substituent. 相似文献
4.
BACKGROUND--Porokeratosis is believed to be a premalignant condition of the skin. Recent flow cytometric studies showing DNA aneuploidy in the epidermis of some types of porokeratosis support this conclusion. We describe a patient with porokeratosis palmaris et plantaris disseminata in whom abnormal DNA ploidy was found in lesional epidermis with the use of flow cytometry. OBSERVATIONS--DNA flow cytometry of lesional epidermis from the back showed two populations of cells, one with diploid and the other with aneuploid DNA content and DNA index of 1.1 (hyperdiploid). The coefficient of variation of the diploid and aneuploid peaks was 2.1% and 4.1%, respectively. CONCLUSIONS--Porokeratosis palmaris et plantaris disseminata, like other forms of porokeratosis, exhibits abnormal DNA ploidy in lesional epidermis. This finding underscores the premalignant nature of this and other forms of porokeratosis. 相似文献
5.
M F Beers A Wali M F Eckenhoff S I Feinstein J H Fisher A B Fisher 《American journal of respiratory cell and molecular biology》1992,7(4):368-378
Surfactant protein C (SP-C) is a lung-specific, hydrophobic peptide found in organic extracts of pulmonary surfactant. Alveolar SP-C (3.5 kD) is produced from proteolytic cleavage of a larger precursor molecule (pro-SP-C; 21 kD). While SP-C is synthesized by type II cells, the pathways for processing and secretion have remained elusive due, in part, to the lack of monospecific antibodies against SP-C or its precursors. This report describes production and characterization of a new antibody directed against pro-SP-C epitopes. Polyclonal antisera (anti-CPRO-SP-C) was prepared using a synthetic peptide corresponding to a portion of rat SP-C cDNA sequence (Ile26-Ser72). This contained amino acids 3-35 of mature SP-C plus additional C-terminal residues (His59-Ser72). On Western blots, anti-CPRO-SP-C competitively reacted to CPRO-SP-C but not to mature SP-C. Immunoblots of in vitro synthesized pro-SP-C confirmed that the antisera also recognized native protein. Immunocytochemistry with anti-CPRO-SP-C demonstrated staining for pro-SP-C peptides in isolated type II cells as well as in alveolar epithelial cells of rat lung sections. Pro-SP-C preferentially co-localized to cells that stained positive for Maclura pomifera antigen. Anti-CPRO-SP-C staining was not observed in lung interstitium, pulmonary vasculature, or several control tissues (brain, heart, and liver were negative). Western blotting of subcellular fractions demonstrated pro-SP-C peptides in plasma membrane (20 kD) and microsomal (20 and 21 kD) fractions with a 16 kD peptide present in lamellar bodies. No pro-SP-C peptides were detected in purified surfactant. These results demonstrate the use of a synthetic peptide to generate specific antiserum against more hydrophilic domains of pro-SP-C sequences and confirm that SP-C propeptides are unique to the lung. 相似文献
6.
7.
Lymph node metastases: safety and effectiveness of MR imaging with ultrasmall superparamagnetic iron oxide particles--initial clinical experience 总被引:14,自引:0,他引:14
8.
Shigellosis is uncommon in the newborn nursery. We describe a case of Shigella sonnei gastroenteritis occurring in a newborn. Three of 32 health care providers caring for the infant acquired shigellosis. The neonate probably acquired the infection from its mother via vertical transmission. All six members of the infant's family had gastroenteritis and two siblings had stool cultures positive for Shigella. Transmission of Shigella in the newborn nursery is potentially great. Emphasis on handwashing and glove use, aggressive case finding, notification of contacts, and a liberal "forced paid sick time" policy may halt the spread. 相似文献
9.
10.