全文获取类型
收费全文 | 8701篇 |
免费 | 670篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 84篇 |
儿科学 | 265篇 |
妇产科学 | 180篇 |
基础医学 | 1199篇 |
口腔科学 | 108篇 |
临床医学 | 1565篇 |
内科学 | 1477篇 |
皮肤病学 | 89篇 |
神经病学 | 803篇 |
特种医学 | 174篇 |
外科学 | 638篇 |
综合类 | 112篇 |
一般理论 | 10篇 |
预防医学 | 1415篇 |
眼科学 | 112篇 |
药学 | 554篇 |
中国医学 | 1篇 |
肿瘤学 | 604篇 |
出版年
2023年 | 95篇 |
2022年 | 84篇 |
2021年 | 160篇 |
2020年 | 135篇 |
2019年 | 226篇 |
2018年 | 226篇 |
2017年 | 201篇 |
2016年 | 187篇 |
2015年 | 237篇 |
2014年 | 319篇 |
2013年 | 441篇 |
2012年 | 696篇 |
2011年 | 678篇 |
2010年 | 335篇 |
2009年 | 305篇 |
2008年 | 569篇 |
2007年 | 611篇 |
2006年 | 584篇 |
2005年 | 603篇 |
2004年 | 514篇 |
2003年 | 558篇 |
2002年 | 493篇 |
2001年 | 61篇 |
2000年 | 50篇 |
1999年 | 74篇 |
1998年 | 110篇 |
1997年 | 74篇 |
1996年 | 56篇 |
1995年 | 58篇 |
1994年 | 59篇 |
1993年 | 64篇 |
1992年 | 34篇 |
1991年 | 35篇 |
1990年 | 28篇 |
1989年 | 30篇 |
1988年 | 33篇 |
1987年 | 27篇 |
1986年 | 27篇 |
1985年 | 33篇 |
1984年 | 39篇 |
1983年 | 30篇 |
1982年 | 27篇 |
1981年 | 32篇 |
1980年 | 27篇 |
1979年 | 13篇 |
1978年 | 15篇 |
1977年 | 13篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1973年 | 10篇 |
排序方式: 共有9390条查询结果,搜索用时 0 毫秒
1.
2.
Sally Ann Lederman 《Journal of human lactation》2006,22(4):387; author reply 387-387; author reply 388
3.
Juin Fok-Seang Linda C. Smith-Thomas Sally Meiners Elizabeth Muir Jian-Sheng Du Elizabeth Housden Alan R. Johnson Andreas Faissner Herbert M. Geller Roger J. Keynes John H. Rogers James W. Fawcett 《Brain research》1995,689(2):207
The adult mammalian central nervous system (CNS) lacks the capacity to support axonal regeneration. There is increasing evidence to suggest that astrocytes, the major glial population in the CNS, may possess both axon-growth promoting and axon-growth inhibitory properties and the latter may contribute to the poor regenerative capacity of the CNS. In order to examine the molecular differences between axon-growth permissive and axon-growth inhibitory astrocytes, a panel of astrocyte cell lines exhibiting a range of axon-growth promoting properties was generated and analysed. No clear correlation was found between the axon-growth promoting properties of these astrocyte cell lines with: (i) the expression of known neurite-outgrowth promoting molecules such as laminin, fibronectin andN-cadherin; (ii) the expression of known inhibitory molecules such tenascin and chondroitin sulphate proteoglycan; (iii) plasminogen activator and plasminogen activator inhibitor activity; and (iv) growth cone collapsing activity. EM studies on aggregates formed from astrocyte cell lines, however, revealed the presence of an abundance of extracellular matrix material associated with the more inhibitory astrocyte cell lines. When matrix deposited by astrocyte cell lines was assessed for axon-growth promoting activity, matrix from permissive lines was found to be a good substrate, whereas matrix from the inhibitory astrocyte lines was a poor substrate for neuritic growth. Our findings, taken together, suggest that the functional differences between the permissive and the inhibitory astrocyte cell lines reside largely with the ECM. 相似文献
4.
Sally Urang Lorna Davis Charlotte Cram Elsberry Mary Kay Kozlowski 《Journal of Midwifery & Women's Health》1993,38(Z1):95s-99s
Fetal scalp blood sampling (FSBS), in conjunction with fetal heart rate monitoring, is a method of fetal surveillance that may avoid cesarean delivery of the healthy fetus or indicate the need for immediate delivery of a compromised fetus. Some researchers have recently begun to question the efficacy of FSBS. In this article, three nurse-midwives discuss FSBS as a tool in assessing fetal well-being during labor and consider whether FSBS is a nurse-midwifery procedure. 相似文献
5.
6.
Frederica Perera Deliang Tang Robin Whyatt Sally Ann Lederman Wieslaw Jedrychowski 《Cancer epidemiology, biomarkers & prevention》2005,14(3):709-714
Polycyclic aromatic hydrocarbons (PAH), of which benzo[a]pyrene is a representative member, are combustion-related environmental pollutants and include known carcinogens. Laboratory animal studies indicate that the dose of PAHs to the fetus is on the order of a 10th that to the mother and that there is heightened susceptibility to PAH-induced carcinogenesis during the fetal and infancy periods. Carcinogen-DNA adducts, a measure of procarcinogenic genetic damage, are considered a biomarker of increased cancer risk. Here we compare the levels of benzo[a]pyrene-DNA adducts as a proxy for PAH-DNA damage measured in maternal blood and newborn cord blood obtained at delivery in four different populations of mothers (total of 867) and newborns (total of 822), representing a 30-fold range of exposure to ambient PAHs. The populations include residents in Northern Manhattan, participants in a study of the effects of the World Trade Center disaster, residents in Krakow, Poland, and residents in Tongliang, China. Mean adduct concentrations in both maternal and cord blood and the proportion of samples with detectable adducts, increased across the populations [Northern Manhattan < World Trade Center (WTC) < Krakow < Tongliang], consistent with the trend in estimated ambient exposure to PAHs (P < 0.001). For mothers, the means in the respective populations were Northern Manhattan (0.21 adducts per 10(8) nucleotides), WTC (0.23 adducts per 10(8) nucleotides), Krakow (0.28 adducts per 10(8) nucleotides), Tongliang (0.31 adducts per 10(8) nucleotides); the corresponding means in the newborns were Northern Manhattan (0.23), WTC (0.24), Krakow (0.29), Tongliang (0.31). The percentage of mothers with detectable levels of adducts in the respective populations were Northern Manhattan (36.8%), WTC (57.5%), Krakow (72.9%), Tongliang (73.4%); the corresponding percentages among the newborns were Northern Manhattan (42.4%), WTC (60.6%), Krakow (71.1%), Tongliang (79.5%). Despite the estimated 10-fold lower PAH dose to the fetus based on laboratory animal experiments, the adduct levels in the newborns were similar to or higher than in the mothers. This study suggests that the fetus may be 10-fold more susceptible to DNA damage than the mother and that in utero exposure to polycyclic aromatic hydrocarbons may disproportionately increase carcinogenic risk. The data support preventive policies to limit PAH exposure to pregnant women and children. 相似文献
7.
Australian nursing has undergone rapid academization in the past 10 years and this radical change has tended to meld the somewhat different academic traditions of North America and Britain. The introduction of doctoral education in nursing in 1987 has led to a massive increase in scholarly activity and to the preparation of talented leaders. We concur with the view expressed by Henry (1997), "I am convinced that the problems we face in the nursing services would be much more creatively solved if the majority of our doctoral programs prepared young, energetic nurses, early in their career, for clinical practice, not for research and teaching" (p. 162). 相似文献
8.
9.
10.