全文获取类型
收费全文 | 1275篇 |
免费 | 151篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 97篇 |
妇产科学 | 21篇 |
基础医学 | 117篇 |
口腔科学 | 44篇 |
临床医学 | 111篇 |
内科学 | 346篇 |
皮肤病学 | 29篇 |
神经病学 | 48篇 |
特种医学 | 249篇 |
外科学 | 72篇 |
综合类 | 98篇 |
预防医学 | 96篇 |
眼科学 | 8篇 |
药学 | 70篇 |
中国医学 | 3篇 |
肿瘤学 | 56篇 |
出版年
2024年 | 3篇 |
2023年 | 15篇 |
2022年 | 11篇 |
2021年 | 30篇 |
2020年 | 24篇 |
2019年 | 11篇 |
2018年 | 21篇 |
2017年 | 46篇 |
2016年 | 41篇 |
2015年 | 33篇 |
2014年 | 69篇 |
2013年 | 77篇 |
2012年 | 30篇 |
2011年 | 31篇 |
2010年 | 69篇 |
2009年 | 72篇 |
2008年 | 37篇 |
2007年 | 74篇 |
2006年 | 51篇 |
2005年 | 29篇 |
2004年 | 27篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 29篇 |
2000年 | 19篇 |
1999年 | 23篇 |
1998年 | 85篇 |
1997年 | 66篇 |
1996年 | 64篇 |
1995年 | 54篇 |
1994年 | 47篇 |
1993年 | 44篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 24篇 |
1987年 | 14篇 |
1986年 | 20篇 |
1985年 | 17篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1975年 | 9篇 |
排序方式: 共有1475条查询结果,搜索用时 15 毫秒
1.
By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6). 相似文献
2.
外科医生和手术室人员经常接触手术设备产生的烟气,病人也会暴露于烟气中,特别是腹腔镜手术中产生的烟气滞留于腹腔内这一密闭空间并被吸收.这些烟气是一种与香烟烟气相似的毒性物质,然而对这种毒性物质的影响还未引起足够重视.应该采取必要措施尽可能减少手术中烟气的不良影响. 相似文献
3.
Toward a VA women’s health research agenda: Setting evidence-based priorities to improve the health and health care of women veterans
下载免费PDF全文
![点击此处可从《Journal of general internal medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elizabeth M. Yano Lori A. Bastian Susan M. Frayne Alexandra L. Howell Linda R. Lipson Geraldine McGlynn Paula P. Schnurr Margaret R. Seaver Ann M. Spungen Stephan D. Fihn 《Journal of general internal medicine》2006,21(3):S93-S101
The expansion of women in the military is reshaping the veteran population, with women now constituting the fastest growing segment of eligible VA health care users. In recognition of the changing demographics and special health care needs of women, the VA Office of Research & Development recently sponsored the first national VA Women’s Health Research Agenda-setting conference to map research priorities to the needs of women veterans and position VA as a national leader in Women’s Health Research. This paper summarizes the process and outcomes of this effort, outlining VA’s research priorities for biomedical, clinical, rehabilitation, and health services research. 相似文献
4.
Theoretical and simulation evidence is presented in support of the idea that the optimal manner of determining blood flow from MR perfusion studies is not necessarily obtained by setting experimental conditions to maximize either the arterial input or the measured tissue concentration level for a particular echo time (TE). The noise power in the contrast concentration curve is associated with its peak because of the nonlinear relationship between the contrast concentration and MR signal intensity curves. The optimum signal-to-noise ratio (SNR), SNR(C), for a particular contrast concentration curve can be obtained when the experimental concentration level and TE are adjusted to produce an MR intensity curve whose signal loss is 63% of the precontrast MR signal intensity. It is demonstrated that the stability of the singular valued decomposition (SVD) deconvolution approach to determine blood flow parameters is increased when the tissue curve maximum signal loss is in the range of 40-80%. The accuracy and stability of the SVD-determined blood flow parameters are affected by deviations from these optimum conditions in a manner that depends on the mean transit time (MTT) associated with the residue function. It is recommended that the experimental TE value be set so that neither the tissue nor the arterial curves are placed a region of rapidly deteriorating SNR(C). 相似文献
5.
6.
7.
8.
9.
10.
Quantitative cerebral blood flow (CBF) values can be obtained from dynamic susceptibility contrast (DSC) MR perfusion studies using the standard singular value decomposition (sSVD) deconvolution algorithm. Reports in the literature from simulation and in vivo studies suggest that CBF estimates obtained using sSVD deconvolution depend on the arterial-tissue delay (ATD). By contrast, Fourier transform (FT) deconvolution produces CBF estimates that are independent of ATD. The diagnostic reliability of quantitative CBF measurements to define areas of normal tissue flow and tissue at risk is brought into doubt by such gross sensitivity to the specifics of the deconvolution approach. This variation of CBF values with ATD is shown to be an artifact associated with the current implementation of the sSVD deconvolution algorithm. A reformulated version of the SVD deconvolution algorithm (rSVD) is presented and compared to the standard SVD algorithm through simulation and patient case studies. 相似文献