全文获取类型
收费全文 | 25234篇 |
免费 | 1877篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 1035篇 |
妇产科学 | 859篇 |
基础医学 | 2917篇 |
口腔科学 | 312篇 |
临床医学 | 4134篇 |
内科学 | 4745篇 |
皮肤病学 | 443篇 |
神经病学 | 2362篇 |
特种医学 | 384篇 |
外科学 | 2039篇 |
综合类 | 346篇 |
一般理论 | 28篇 |
预防医学 | 3729篇 |
眼科学 | 365篇 |
药学 | 1569篇 |
中国医学 | 34篇 |
肿瘤学 | 1741篇 |
出版年
2023年 | 176篇 |
2022年 | 200篇 |
2021年 | 404篇 |
2020年 | 346篇 |
2019年 | 554篇 |
2018年 | 634篇 |
2017年 | 513篇 |
2016年 | 552篇 |
2015年 | 614篇 |
2014年 | 838篇 |
2013年 | 1333篇 |
2012年 | 1965篇 |
2011年 | 1929篇 |
2010年 | 1087篇 |
2009年 | 1024篇 |
2008年 | 1655篇 |
2007年 | 1819篇 |
2006年 | 1698篇 |
2005年 | 1751篇 |
2004年 | 1662篇 |
2003年 | 1502篇 |
2002年 | 1450篇 |
2001年 | 226篇 |
2000年 | 177篇 |
1999年 | 201篇 |
1998年 | 294篇 |
1997年 | 216篇 |
1996年 | 192篇 |
1995年 | 200篇 |
1994年 | 173篇 |
1993年 | 149篇 |
1992年 | 111篇 |
1991年 | 96篇 |
1990年 | 110篇 |
1989年 | 97篇 |
1988年 | 74篇 |
1987年 | 72篇 |
1986年 | 73篇 |
1985年 | 89篇 |
1984年 | 99篇 |
1983年 | 71篇 |
1982年 | 92篇 |
1981年 | 77篇 |
1980年 | 71篇 |
1979年 | 50篇 |
1978年 | 55篇 |
1977年 | 41篇 |
1975年 | 35篇 |
1973年 | 24篇 |
1972年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
61.
62.
63.
James C Slaughter Thomas Lumley Lianne Sheppard Jane Q Koenig Gail G Shapiro 《Annals of allergy, asthma & immunology》2003,91(4):346-353
BACKGROUND: Exposure to air pollutants has been investigated as a possible cause of asthma attacks in children. OBJECTIVE: To investigate the short-term effects of air pollutants on a panel of 133 children with asthma who enrolled in the Childhood Asthma Management Program. METHODS: During screening, the children completed daily diary cards for an average of 58 days to indicate their medication use and asthma severity. We used ordinal logistic regression to compare the odds of a more serious relative to a less serious asthma attack, and we used a Poisson model to analyze medication use. In both analyses we accommodate dependence in the data and different periods of observation for study subjects. RESULTS: Our results indicate that a 10-microg/m3 increase in particulate matter less than or equal to 2.5 microm (PM2.5) lagged 1 day was associated with a 1.20 times increased odds of having a more serious asthma attack [95% confidence interval (CI), 1.05 to 1.37] and a 1.08-fold increase in medication use (95% CI, 1.01 to 1.15). A 10-microg/m3 increase in particulate matter less than or equal to 10 microm (PM10) increased the odds of a more serious asthma attack (odds ratio = 1.12; 95% CI, 1.04 to 1.22) and also increased medication use (relative risk = 1.05; 95% CI, 1.00 to 1.09). CONCLUSIONS: Increases in PM2.5 and PM10 are significantly associated with an increased risk of more severe asthma attacks and medication use in Seattle area children with asthma. We also found associations with carbon monoxide, but we believe that carbon monoxide is a marker for exposure to combustion byproducts. 相似文献
64.
Children today experience many transitions within their school careers. One transition in particular, from preschool to kindergarten presents many challenges for children, families, and teachers. A model for planning and carrying out this transition is presented. The model includes developing and implementing the transition process. 相似文献
65.
Doug Joshua Max Wolf Jane Matthews Lee Tan William Sheridan Glenn Pilkingtonh Fiona Page 《Leukemia & lymphoma》1994,14(3):303-309
The Australian Leukaemia Study Group myeloma study (MM1) aimed to determine the prognostic significance of clinical and immunophenotypic markers in patients with multiple myeloma. All patients were treated with standard dose melphalan and prednisone. Seventy-four patients were entered and the median survival was 27 months. Serum beta 2-microglobulin (βM) and albumin levels were the only significant clinical factors influencing survival (p = 0.007 and p = 0.008, respectively). Patients with raised levels of CD38+ lymphocytes at presentation had a significantly shorter survival than patients with normal levels (p = 0.01, logrank test, median 19 months vs 33 months). CD38 antigen expression was independent of β2M but patients with raised levels of CD38 had significantly lower levels of albumin than patients with normal levels (p = 0.001) which may explain their poorer survival. Salmon and Durie stage was not associated with antigen expression. No other B-cell antigens (CD10, CD19, CD20, CD21, CD22, CD23, FMC1 or FMC7) or plasma cell antigens tested (PCA-1) were found to be associated with prognosis. Patients who achieved plateau phase had a better prognosis than those who did not (p = 0.04 in a landmark analysis). Patients who achieved plateau phase following an objective response appeared to have a better prognosis than those who were in plateau phase at presentation (p = 0.09 in a landmark analysis). Light chain isotype suppression (LCIS) was not associated with a significant survival advantage and did not correlate with any known prognostic indicator. We conclude that phenotypic analysis of peripheral blood lymphocytes for CD38 antigen at diagnosis may be useful as a prognostic indicator in patients with myeloma. 相似文献
66.
The effect of a systemic (IP) treatment with 1.0, 3.0 and 9.0 mg/kg U-50,488H (U50), a highly selective kappa-agonist, on spontaneous, nocturnal ingestive behavior of the rat was studied using a microcomputer controlled data acquisition system. The latency to initiate drinking was increased and drinking behavior was suppressed in the first hour after injection in a dose-dependent manner. The consummatory indices of drinking were not affected. After this period of adipsia, a phase of polydipsia, that was probably due to the diuretic effect of U50, was evident. The prophagic effect of U50 was evident only at the dose of 3 mg/kg and was accompanied by an increased duration of feeding episodes but not by a reduced latency to feed. These results suggest that kappa-receptors play a pivotal role in modulating spontaneous drinking in the normally hydrated rat and that this control is mainly exerted on the motivational aspect of drinking. 相似文献
67.
68.
69.
70.