全文获取类型
收费全文 | 7520篇 |
免费 | 732篇 |
国内免费 | 192篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 182篇 |
妇产科学 | 93篇 |
基础医学 | 691篇 |
口腔科学 | 109篇 |
临床医学 | 905篇 |
内科学 | 1038篇 |
皮肤病学 | 91篇 |
神经病学 | 416篇 |
特种医学 | 219篇 |
外科学 | 712篇 |
综合类 | 1313篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 923篇 |
眼科学 | 167篇 |
药学 | 814篇 |
3篇 | |
中国医学 | 385篇 |
肿瘤学 | 305篇 |
出版年
2024年 | 20篇 |
2023年 | 54篇 |
2022年 | 137篇 |
2021年 | 268篇 |
2020年 | 198篇 |
2019年 | 125篇 |
2018年 | 138篇 |
2017年 | 171篇 |
2016年 | 125篇 |
2015年 | 259篇 |
2014年 | 296篇 |
2013年 | 394篇 |
2012年 | 551篇 |
2011年 | 556篇 |
2010年 | 481篇 |
2009年 | 395篇 |
2008年 | 517篇 |
2007年 | 546篇 |
2006年 | 441篇 |
2005年 | 324篇 |
2004年 | 284篇 |
2003年 | 272篇 |
2002年 | 204篇 |
2001年 | 170篇 |
2000年 | 187篇 |
1999年 | 122篇 |
1998年 | 56篇 |
1997年 | 66篇 |
1996年 | 46篇 |
1995年 | 42篇 |
1994年 | 36篇 |
1993年 | 42篇 |
1992年 | 88篇 |
1991年 | 71篇 |
1990年 | 70篇 |
1989年 | 63篇 |
1988年 | 64篇 |
1987年 | 50篇 |
1986年 | 61篇 |
1985年 | 48篇 |
1984年 | 40篇 |
1983年 | 34篇 |
1982年 | 25篇 |
1981年 | 28篇 |
1980年 | 24篇 |
1979年 | 33篇 |
1978年 | 23篇 |
1976年 | 20篇 |
1975年 | 18篇 |
1974年 | 16篇 |
排序方式: 共有8444条查询结果,搜索用时 578 毫秒
991.
992.
Age and response rates to interview sample surveys 总被引:3,自引:0,他引:3
The relationship between response rate--a basic indicator of the quality of survey data--and age is investigated. Standard definitions of general and age-specific response rates are presented first. In a systematic assessment of response rates by age, data from several large interview sample surveys and panel resurveys are then examined. Response rates are found to decline linearly with increasing age in both types of surveys, although the decline is not always statistically significant. Potential causes and consequences of low response rates among elderly persons are discussed. 相似文献
993.
JOHAN HERLITZ KE HJALMARSON KARL SWEDBERG LARS RYDN FINN WAAGSTEIN 《Journal of internal medicine》1988,223(3):227-231
ABSTRACT This study reports the mortality over a 5-year-period determined a double-blind trial, which evaluated the effect of early intervention with metoprolol in suspected acute myocardial infarction. In all, there were 1 395 randomized patients, 698 and 697 of whom were allocated to metoprolol 200 mg daily and placebo treatments, respectively, for the first 3 months. Thereafter, the two groups were treated in a similar fashion implying β-blockade to a majority. Within the first 3 months, mortality in the metoprolol group was 5.7% versus 8.9% of the placebo group (p = 0.02). This difference persisted after 2 years (metoprolol 13.2%; placebo 17.2%; p = 0.04). Over a 5-year-period, 24.2% of the patients who originally were allocated to metoprolol had died as compared to 25.7% of those originally allocated to placebo (p > 0.2). Among patients in whom treatment started early (≤ 8 hours after onset of pain = the median delay time), enzyme activities in the metoprolol group was lower (p = 0.03) than in the placebo group. Mortality during the first 2 years among these patients treated early was lower in the metoprolol (11.8%) than in the placebo group (17.3%; p = 0.04). Corresponding figures after 5 years were 22.0% and 25.3%, respectively (p > 0.2). Among patients in whom treatment started later than 8 hours onset of pain, there was neither any difference in enzyme activity nor in mortality after 2 and 5 years. It can be concluded that early treatment with metoprolol in suspected acute myocardial infarction reduced mortality during the first 3 months compared with placebo. The difference persisted after 2 years. However, 5 years after randomization, no significant difference in mortality was observed between the two treatment groups. 相似文献
994.
995.
Acute administration of O,O,S-trimethyl phosphorothioate (OOS-TMP), an impurity in technical formulations of malathion, to female C57B1/6 mice was previously shown to suppress the generation of both cytotoxic T lymphocyte to alloantigen and antibody-secreting cells to sheep red blood cells. In this report, macrophages were shown to be the immune cell population most affected by acute OOS-TMP pretreatment by cell separation and reconstitution experiments. Macrophages from OOS-TMP-treated animals had increased levels of nonspecific esterases. In addition, the size distribution of macrophages from treated animals was slightly larger and more heterogeneous than macrophages from control animals. However, macrophages from OOS-TMP-treated animals did not exhibit tumoricidal activity. These data suggest that macrophages from OOS-TMP-treated animals were similar to those located in nonimmune inflammatory sites. 相似文献
996.
Abstract – Histopathologic and clinical reexamination of 84 cases diagnosed as peripheral odontogenic fibroma showed 56 cases with no evidence of recurrence, 12 with possible single recurrence and 16 with verified single or multiple recurrences. An effort was made to correlate the histopathologic appearance with the recurrence rate. Three different types of lesions could be identified: fibrous epulis, calcifying fibroblastic granuloma and various types of "fibroma", all showing a high recurrence rate. Our findings show that neither histomorphology nor recurrence rate can be used as a definite criterium to separate neoplasia such as odontogenic fibroma from other gingival fibrous overgrowths. 相似文献
997.
J J Hurwitz M Lichter J Rodgers 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》1983,18(6):269-273
Ectropion is sometimes due to a shortage of skin of the lower lid (cicatricial) and may result from previous surgery, trauma, burns, skin diseases etc. Excessive exposure to the sun has also been incriminated. Vertical traction lines in the skin of the lower lid, accentuated by gazing up or by opening the mouth, suggest this condition. This paper describes the use of pedicle skin flaps rotated from the upper lid to treat cicatricial ectropion occurring in the absence of any predisposing factor and not responding to conservative treatment--that is, due to essential skin shrinkage. All 10 patients had an improved appearance, and epiphora persisted in only 1 patient, who subsequently underwent a punctum-enlarging procedure. In an 11th patient there was insufficient redundant upper-lid skin, so a free skin graft was used instead. 相似文献
998.
999.
1000.