全文获取类型
收费全文 | 1078篇 |
免费 | 88篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 50篇 |
妇产科学 | 10篇 |
基础医学 | 101篇 |
口腔科学 | 43篇 |
临床医学 | 84篇 |
内科学 | 146篇 |
皮肤病学 | 29篇 |
神经病学 | 22篇 |
特种医学 | 306篇 |
外科学 | 143篇 |
综合类 | 42篇 |
一般理论 | 1篇 |
预防医学 | 56篇 |
眼科学 | 18篇 |
药学 | 27篇 |
肿瘤学 | 109篇 |
出版年
2021年 | 6篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 25篇 |
2013年 | 18篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 30篇 |
2009年 | 28篇 |
2008年 | 30篇 |
2007年 | 25篇 |
2006年 | 29篇 |
2005年 | 19篇 |
2004年 | 24篇 |
2003年 | 18篇 |
2002年 | 10篇 |
2001年 | 24篇 |
2000年 | 18篇 |
1999年 | 21篇 |
1998年 | 42篇 |
1997年 | 48篇 |
1996年 | 49篇 |
1995年 | 40篇 |
1994年 | 27篇 |
1993年 | 36篇 |
1992年 | 30篇 |
1991年 | 28篇 |
1990年 | 23篇 |
1989年 | 38篇 |
1988年 | 38篇 |
1987年 | 56篇 |
1986年 | 35篇 |
1985年 | 28篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 17篇 |
1981年 | 21篇 |
1980年 | 20篇 |
1979年 | 16篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 28篇 |
1975年 | 13篇 |
1974年 | 5篇 |
1972年 | 7篇 |
1971年 | 8篇 |
1926年 | 4篇 |
排序方式: 共有1189条查询结果,搜索用时 9 毫秒
1.
2.
Effect of blockade of TNF-alpha and interleukin-1 action on bone resorption in early postmenopausal women. 总被引:1,自引:0,他引:1
Natthinee Charatcharoenwitthaya Sundeep Khosla Elizabeth J Atkinson Louise K McCready B Lawrence Riggs 《Journal of bone and mineral research》2007,22(5):724-729
After acute estrogen withdrawal in postmenopausal women, administration of anakinra or etanercept, specific blockers of IL-1 and TNF-alpha, respectively, reduced the rise in bone resorption markers to about one half of that in controls. This is consistent with an important role for these immune cytokines in mediating the effect of estrogen deficiency on bone. INTRODUCTION: Studies in rodents have implicated increased production of interleukin (IL)-1 beta and TNF-alpha as mediators of bone loss after ovariectomy, but their roles are unclear in humans whose immune system differs markedly from that of rodents. MATERIALS AND METHODS: We administered transdermal estradiol, 0.1 mg/d, for 60 days to 42 early postmenopausal women. Estrogen treatment was discontinued, and subjects were randomly assigned to intervention groups receiving 3 wk of injections with 0.9% saline, anakinra 100 mg/d, or etanercept 25 mg/twice weekly. Bone turnover was assessed by measuring serum carboxyl-terminal telopeptide of type 1 collagen (CTX) and amino-terminal telopeptide of type 1 collagen (NTX), markers for bone resorption, and serum amino-terminal propeptide of type 1 collagen (P1NP), a marker for bone formation. Results were expressed as percent change in markers from baseline (last 2 days of estrogen treatment and days 20 and 21 of intervention). RESULTS: The percent changes from baseline during intervention for serum CTX, urine NTX, and serum PINP, respectively, were 43.3 +/- 8.0%, 12.0 +/- 7.1%, and -41.0 +/- 2.5% for the control group; 25.9 +/- 6.3%, 9.5 +/- 4.0%, and -37.8 +/- 3.0% for the anakinra group; and 21.7 +/- 5.0%, 0.32 +/- 3.82%, and -34.5 +/- 3.9% for the etanercept group. Compared with the control group, the blunting of the increase in serum CTX fell just below the level of significance (p=0.10) after anakinra treatment, whereas the blunting of the increase in serum CTX (p=0.034) and in urine NTX (p=0.048) were significant after etanercept treatment. Other changes were not significant. CONCLUSIONS: The data are consistent with a role for TNF-alpha, and possibly for IL-1 beta, in mediating increased bone resorption during estrogen deficiency in women. Although either cytokine blocker reduced serum CTX by about one half, the effect of combined blockade could not be tested because of concerns about toxicity. The data do not exclude direct or indirect contributory roles for RANKL or for other cytokines. 相似文献
3.
J W Babich F Keeling M A Flower L Repetto A Whitton S Fielding A Fullbrook R J Ott V R McCready 《European journal of nuclear medicine》1988,14(1):39-44
A preliminary study of the distribution of the 99mTc complex of hexamethylpropylene amine oxime (HM-PAO) in 12 patients with brain neoplasms before, during, and after radiotherapy has been performed. Untreated brain tumors were found to exhibit a range of 99mTc-HM-PAO uptake, varying from areas of markedly increased isotope activity to photopenic areas, when compared to normal brain tissue. A ratio of 99mTc-HM-PAO tumor uptake to contralateral normal tissue uptake was calculated prior to and during radiotherapy. This ratio tended to return towards unity in lesions responding to therapy. A predictable alteration in whole brain 99mTc-HM-PAO uptake during radiotherapy was not demonstrated. Unlike the radiolabeled amines, 99mTc-HM-PAO localizes in primary tumors, probably indicating that its uptake mechanism is independent of non specific amine receptors. 99mTc-HM-PAO may be useful in the study of brain tumor physiology and response to therapy. 相似文献
4.
5.
6.
7.
Anand Shah Danny O Jacobs Henrique Martins Matthew Harker Andreia Menezes Mariana McCready Ricardo Pietrobon 《BMC medical informatics and decision making》2006,6(1):34
Background
The Internet has been increasingly utilized in biomedical research. From online searching for literature to data sharing, the Internet has emerged as a primary means of research for many physicians and scientists. As a result, Web-based surveys have been employed as an alternative to traditional, paper-based surveys. We describe DADOS-Survey, an open-source Web-survey application developed at our institution that, to the best of our knowledge, is the first to be compliant with the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). DADOS-Survey was designed with usability as a priority, allowing investigators to design and execute their own studies with minimal technical difficulties in doing so. 相似文献8.
9.
10.
A bloodless technique of evaluating protein catabolic rate (PCR) and KT/V (K, clearance; T, dialysis time; V, urea distribution volume) in hemodialysis patients is presented based on serial measurement of urea in the dialysate effluent stream. PCR follows from equating urea generation and urea removal over a 7 day cycle, changes in body stores being comparatively negligible: PCR = 0.026 [U1 + U2 + U3]/BWdry + 0.17, where U1 is the amount of urea in mmol appearing in the dialysate for each session in the 7 day period. KT/V is obtained from the slope of the natural logarithm of spent dialysate urea concentration-time plot: KT/V = [- slope.T + 3.delta BW/BWdry]/[1 - 0.01786.T(hr], where delta BW = amount ultrafiltered in liters. The dialysate-based approach was validated and compared with conventional urea kinetic modeling (UKM) for 17 patients studied for three consecutive dialyses. The dialysate-based and UKM values of PCR agreed well when in vivo clearance values based on total dialysate collection were used for UKM. KT/V values agreed poorly on a session-by-session basis but were nearly equivalent when averaged for the three dialyses of the week. These findings lay the foundation for UKM automation with a urea sensor in the effluent dialysate stream. 相似文献