全文获取类型
收费全文 | 47145篇 |
免费 | 4382篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 612篇 |
儿科学 | 1261篇 |
妇产科学 | 1316篇 |
基础医学 | 6816篇 |
口腔科学 | 1252篇 |
临床医学 | 5799篇 |
内科学 | 8257篇 |
皮肤病学 | 596篇 |
神经病学 | 3783篇 |
特种医学 | 2064篇 |
外国民族医学 | 1篇 |
外科学 | 6165篇 |
综合类 | 859篇 |
一般理论 | 23篇 |
预防医学 | 5250篇 |
眼科学 | 1089篇 |
药学 | 3543篇 |
2篇 | |
中国医学 | 56篇 |
肿瘤学 | 2858篇 |
出版年
2021年 | 655篇 |
2019年 | 640篇 |
2018年 | 747篇 |
2017年 | 627篇 |
2016年 | 610篇 |
2015年 | 702篇 |
2014年 | 942篇 |
2013年 | 1469篇 |
2012年 | 2132篇 |
2011年 | 2216篇 |
2010年 | 1193篇 |
2009年 | 978篇 |
2008年 | 1862篇 |
2007年 | 2010篇 |
2006年 | 2006篇 |
2005年 | 2003篇 |
2004年 | 1821篇 |
2003年 | 1667篇 |
2002年 | 1699篇 |
2001年 | 1600篇 |
2000年 | 1705篇 |
1999年 | 1442篇 |
1998年 | 626篇 |
1997年 | 493篇 |
1996年 | 508篇 |
1995年 | 513篇 |
1994年 | 428篇 |
1993年 | 445篇 |
1992年 | 1255篇 |
1991年 | 1161篇 |
1990年 | 1145篇 |
1989年 | 1071篇 |
1988年 | 982篇 |
1987年 | 990篇 |
1986年 | 908篇 |
1985年 | 908篇 |
1984年 | 709篇 |
1983年 | 627篇 |
1982年 | 440篇 |
1981年 | 386篇 |
1980年 | 400篇 |
1979年 | 655篇 |
1978年 | 520篇 |
1977年 | 409篇 |
1976年 | 399篇 |
1975年 | 372篇 |
1974年 | 451篇 |
1973年 | 438篇 |
1972年 | 450篇 |
1971年 | 423篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Ten patients with rheumatoid arthritis (RA) were evaluated in a placebo-controlled, double-blind study examining the clinical efficacy of a novel nonsteroidal anti-inflammatory agent: Tenidap (CP-66,248). RA patients receiving active drug therapy (n = 6) demonstrated clinically significant improvements in observer assessment of pain (p less than 0.025), painful joint count (p less than 0.010), and overall clinical assessment as based on a modified rheumatoid activity index, MRAI (p less than 0.025). In parallel laboratory assays, Tenidap was found to exhibit a significant in vitro dose-dependent inhibition of ionophore-stimulated neutrophil production of the 5-lipoxygenase product: [3H]leukotriene B4 (LTB4). Although more importantly, Tenidap was also found to exhibit an in vitro dose-dependent inhibition (IC50 20 microM) of the ionophore-stimulated release (deacylation) of the precursor [3H]arachidonic acid (AA) from membrane phospholipids. In further studies, Tenidap did not have any effect on fMLP-induced neutrophil chemotactic response. These results suggest that one of the possible mechanisms for the clinical effectiveness of this agent, may be through its effect at inhibiting the release of free AA from membrane phospholipids and therefore limiting its further metabolism into certain biologically-active inflammatory lipids. 相似文献
22.
OBJECTIVES: The purpose of this study was to identify individual characteristics associated with types and frequency of milk consumption in older American adults. METHODS: A national probability-based sample (response rate = 91%) completed a telephone survey. Generalized logit and cumulative logit analyses were used to identify predictors of and barriers to fluid milk consumption in 494 elderly people. RESULTS: The likelihood of drinking skim or 1% milk rather than whole milk increased with nutrition knowledge, income, trying to reduce cholesterol intake, and being female (P < .05). Frequency of milk consumption was higher with nutrition knowledge, frequency of milk consumption during adolescence, and following a diabetic diet but was lower with milk intolerance. CONCLUSIONS: The present results could be used to develop intervention strategies for improving milk consumption rates among older adults. These strategies might focus on increasing elderly people's awareness of milk intolerance and lactose-reduced milk products and their concern about cholesterol. The relationship between current and adolescent milk consumption suggests that intervention strategies should begin early in life. 相似文献
23.
J M Johnson 《The Journal of the American Osteopathic Association》1990,90(4):346-351
Clinicians and researchers alike have questioned and studied the origin of schizophrenia for decades. Since the early 1900s, a genetic hypothesis has been suggested. This article reviews studies on a possible genetic cause of schizophrenia by use of various methods of comparison: twins, adoption, family history, family studies, and studies of biologic markers. Most researchers conclude that schizophrenia is likely caused by a genetic predisposition coupled with environmental influences. 相似文献
24.
25.
E K Lund W E Lee-Finglas S Southon J M Gee I T Johnson P M Finglas A J Wright 《European journal of clinical nutrition》1992,46(12):857-864
The relationship between dietary fat intake and fasting plasma lipid levels was assessed in 35 female and 19 male adolescents recruited from two local education authority schools in Norwich, UK. Dietary intakes were assessed using a 7-day weighed dietary record method, coupled with the collection of duplicate diets. Fat and energy intakes calculated using food composition tables were compared with values obtained by direct analysis of duplicate diets. Fasting plasma lipid levels (total, HDL and LDL cholesterol and triglycerides) were measured and compared with total dietary lipids and fatty acid intakes. The average proportion of energy consumed as fat was higher than is currently considered desirable but lower than previous studies have reported for adults. Mean serum total cholesterol values were 4.2 (SEM 0.1) mmol for females and 4.5 (SEM 0.2) mmol for males; this difference was not statistically significant. In male subjects the dietary fatty acid profiles were significantly correlated with several parameters of plasma lipid status which are thought to be risk factors for coronary heart disease, and in particular with the ratio of total:HDL cholesterol. 相似文献
26.
27.
28.
Inflammatory central nervous system disease in lupus-prone MRL/lpr mice: comparative histologic and immunohistochemical findings 总被引:7,自引:0,他引:7
Catherine M. Vogelweid Gayle C. Johnson Cynthia L. Besch-Williford Joe Basler Sara E. Walker 《Journal of neuroimmunology》1991,35(1-3):89-99
The brains of pathogen-free autoimmune MRL/lpr, NZBWF1 and NZB mice were examined for central nervous system (CNS) inflammation in premoribund 8-week-old animals and at ages when active systemic lupus erythematosus (SLE) was present. CNS inflammation was observed only in MRL/lpr mice. Immunohistochemical studies of brains from young MRL/lpr mice found that infiltrates were composed primarily of CD4+ cells. Older MRL/lpr mice (22 and 26 weeks of age) had CD4+ cells predominantly, but CD8+ and B220+ cells were also present. Perivascular leakage of IgG was a prominent and unexpected finding in the MRL/lpr model. Congenic MRL/+ mice with late-onset autoimmunity had no inflammatory cells in brain tissue, and there was no perivascular staining with IgG or albumin. Our findings suggest that MRL/lpr mice are a useful model for studies of lupus-associated CNS inflammatory disease, and perivascular leakage may be a primary mechanism for entry of IgG into the brain. 相似文献
29.
CT appearance of cervical lipoblastoma 总被引:1,自引:0,他引:1
W C Black J W Burke P S Feldman C M Johnson S Swanson 《Journal of computer assisted tomography》1986,10(4):696-698
We describe a case of lipoblastoma causing respiratory symptoms in an infant, where CT was useful in establishing the diagnosis and demonstrating the extent of involvement so that complete surgical resection could be planned. 相似文献
30.
Theodore Colton Laurence Freedman Tony Johnson David MaChin 《Statistics in medicine》1989,8(6):639-639