全文获取类型
收费全文 | 2687篇 |
免费 | 164篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 74篇 |
妇产科学 | 30篇 |
基础医学 | 342篇 |
口腔科学 | 93篇 |
临床医学 | 191篇 |
内科学 | 726篇 |
皮肤病学 | 85篇 |
神经病学 | 244篇 |
特种医学 | 145篇 |
外科学 | 394篇 |
综合类 | 23篇 |
一般理论 | 1篇 |
预防医学 | 173篇 |
眼科学 | 63篇 |
药学 | 147篇 |
中国医学 | 4篇 |
肿瘤学 | 116篇 |
出版年
2023年 | 28篇 |
2022年 | 61篇 |
2021年 | 120篇 |
2020年 | 59篇 |
2019年 | 82篇 |
2018年 | 84篇 |
2017年 | 67篇 |
2016年 | 77篇 |
2015年 | 74篇 |
2014年 | 105篇 |
2013年 | 146篇 |
2012年 | 219篇 |
2011年 | 227篇 |
2010年 | 121篇 |
2009年 | 103篇 |
2008年 | 164篇 |
2007年 | 164篇 |
2006年 | 165篇 |
2005年 | 133篇 |
2004年 | 146篇 |
2003年 | 140篇 |
2002年 | 97篇 |
2001年 | 37篇 |
2000年 | 22篇 |
1999年 | 24篇 |
1998年 | 25篇 |
1997年 | 25篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有2868条查询结果,搜索用时 250 毫秒
1.
2.
B.B. Damian T.C.S. Bonetti D.D.G. Horovitz 《Brazilian journal of medical and biological research》2015,48(1):25-33
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose
embryo-related genetic abnormalities for couples who present a high risk of a
specific inherited disorder. Because this technology involves embryo selection, the
medical, bioethical, and legal implications of the technique have been debated,
particularly when it is used to select features that are not related to serious
diseases. Although several initiatives have attempted to achieve regulatory
harmonization, the diversity of healthcare services available and the presence of
cultural differences have hampered attempts to achieve this goal. Thus, in different
countries, the provision of PGD and regulatory frameworks reflect the perceptions of
scientific groups, legislators, and society regarding this technology. In Brazil,
several texts have been analyzed by the National Congress to regulate the use of
assisted reproduction technologies. Legislative debates, however, are not conclusive,
and limited information has been published on how PGD is specifically regulated. The
country requires the development of new regulatory standards to ensure adequate
access to this technology and to guarantee its safe practice. This study examined
official documents published on PGD regulation in Brazil and demonstrated how little
direct oversight of PGD currently exists. It provides relevant information to
encourage reflection on a particular regulation model in a Brazilian context, and
should serve as part of the basis to enable further reform of the clinical practice
of PGD in the country. 相似文献
3.
Richard B Thompson Ewout J van den Bos Bryce H Davis Yoshihisa Morimoto Damian Craig Brad S Sutton Donald D Glower Doris A Taylor 《The Journal of heart and lung transplantation》2005,24(2):205-214
BACKGROUND: Pre-clinical and clinical studies suggest that transplantation of bone marrow-derived stem cells can improve global cardiac function. However, no quantitative assessment of regional systolic contraction and correlation with phenotype has been made. Therefore, we used our model of cryoinfarcted rabbit myocardium for intracardiac transplantation of a mixed population of bone marrow-derived cells and assessed both regional function and myogenic conversion of the cells. METHODS: Nineteen New Zealand white rabbits underwent cryoinjury of the left ventricle. Autologous bone marrow (BM) cells were expanded in vitro. After 2 weeks, either 1 x 10(8) mixed BM-derived progenitor cells (BM group, n = 11) or vehicle (control group, n = 8) were injected into the cryoinjured region. Regional systolic function was measured using micromanometry and sonomicrometry before and 4 weeks after cell injection; cell phenotype was evaluated histologically. RESULTS: All animals in the BM group significantly improved both systolic shortening (0.11 +/- 0.7 vs -0.05 +/- 0.05 mm in the control group, p < 0.05) and regional stroke work when compared with control (9.6 +/- 2.4 vs -1.2 +/- 1.2 mm . mm Hg, p < 0.003). In addition, the BM group had improved global diastolic function, as measured by minimum dP/dt and end-diastolic pressure. On histologic assessment, BM cells differentiated toward a myogenic phenotype. CONCLUSIONS: Transplanting a mixed population of marrow-derived cells that can adopt a myogenic phenotype improves regional contractility and diastolic relaxation after myocardial infarction. 相似文献
4.
Adverse outcomes of planned and unplanned pregnancies among users of natural family planning: a prospective study. 总被引:3,自引:1,他引:2
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A Bitto R H Gray J L Simpson J T Queenan R T Kambic A Perez P Mena M Barbato C Li V Jennings 《American journal of public health》1997,87(3):338-343
OBJECTIVES: The purpose of this study was to determine prospectively whether unplanned pregnancies are associated with adverse pregnancy outcomes among users of natural family planning. METHODS: Women who became pregnant while using natural family planning were identified in five centers worldwide: there were 373 unplanned and 367 planned pregnancies in this cohort. The subjects were followed up at 16 and 32 weeks' gestation and after delivery. The risks of spontaneous abortion, low birth-weight, and preterm birth were estimated after adjustment by logistic regression. RESULTS: The women with unplanned pregnancies were more likely to be at the extremes of age, to report more medical problems before and during the index pregnancy, and to seek antenatal care later in gestation than the women with planned pregnancies. However, women with planned pregnancies reported a higher rate of spontaneous abortion in previous pregnancies (28.8%) than did women with unplanned pregnancies (12.9%). There were no significant differences in the rates of spontaneous abortion, low birthweight, or preterm birth between the two groups. CONCLUSIONS: No increased risk of adverse pregnancy outcomes was observed among women who experienced an unplanned pregnancy while using natural family planning. 相似文献
5.
6.
7.
The authors describe a case of ventricular fibrillation occasionally induced by high rate transesophageal pacing, performed to treat an atrial flutter. They conclude that, although this technique is generally safe and well tolerated, it must be performed exclusively where an intensive care can be provided. 相似文献
8.
Thomas Patrick S. Jr; Fraley Gregory S.; Damian Vincent; Woodke Lillie B.; Zapata Francisco; Sopher Bryce L.; Plymate Stephen R.; La Spada Albert R. 《Human molecular genetics》2006,15(19):2972
Human Molecular 相似文献
9.
10.