全文获取类型
收费全文 | 2000篇 |
免费 | 242篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 105篇 |
妇产科学 | 22篇 |
基础医学 | 290篇 |
口腔科学 | 106篇 |
临床医学 | 219篇 |
内科学 | 444篇 |
皮肤病学 | 36篇 |
神经病学 | 164篇 |
特种医学 | 168篇 |
外科学 | 246篇 |
综合类 | 16篇 |
一般理论 | 1篇 |
预防医学 | 143篇 |
眼科学 | 30篇 |
药学 | 139篇 |
中国医学 | 4篇 |
肿瘤学 | 113篇 |
出版年
2021年 | 23篇 |
2020年 | 17篇 |
2019年 | 28篇 |
2018年 | 74篇 |
2017年 | 49篇 |
2016年 | 41篇 |
2015年 | 45篇 |
2014年 | 48篇 |
2013年 | 77篇 |
2012年 | 66篇 |
2011年 | 78篇 |
2010年 | 55篇 |
2009年 | 60篇 |
2008年 | 70篇 |
2007年 | 90篇 |
2006年 | 70篇 |
2005年 | 117篇 |
2004年 | 149篇 |
2003年 | 85篇 |
2002年 | 58篇 |
2001年 | 61篇 |
2000年 | 48篇 |
1999年 | 58篇 |
1998年 | 37篇 |
1997年 | 48篇 |
1996年 | 31篇 |
1995年 | 26篇 |
1994年 | 33篇 |
1993年 | 34篇 |
1992年 | 34篇 |
1991年 | 32篇 |
1990年 | 32篇 |
1989年 | 39篇 |
1988年 | 37篇 |
1987年 | 40篇 |
1986年 | 32篇 |
1985年 | 33篇 |
1984年 | 16篇 |
1983年 | 24篇 |
1982年 | 16篇 |
1981年 | 14篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 15篇 |
1977年 | 21篇 |
1976年 | 13篇 |
1975年 | 19篇 |
1974年 | 15篇 |
1973年 | 10篇 |
1972年 | 10篇 |
排序方式: 共有2254条查询结果,搜索用时 15 毫秒
51.
Versluis RG Petri H Vismans FJ van de Ven CM Springer MP Papapoulos SE 《Calcified tissue international》2000,66(1):1-4
Radiographic absorptiometry (RA) of the phalanges is a convenient and reliable technique for measuring bone mineral density
(BMD). It needs only a radiograph of the hand, which can be sent for evaluation to a central facility, whereas other techniques
require specialized equipment. We assessed the relationship between RA measurements and the presence of vertebral deformities
in a population-based cohort of postmenopausal women, and to compare the results with simultaneously obtained BMD of the hip
by dual-energy X-ray absorptiometry (DXA). A total of 389 women aged 55–84 (mean age 67.2 years, SD 8.7) were randomly selected
from a large general practice. RA, DXA of the hip, and vertebral deformities in the lateral spine X-rays by vertebral morphometry
were assessed. Thirty-eight women (9.8%) had severe (grade II) vertebral deformities, and their BMD at the phalanges and femoral
neck was significantly lower than that of women without severe vertebral deformities. Odds ratios for the presence of severe
vertebral deformities of 1.5 (95% CI: 1.1–2.1) for RA and 1.3 (95% CI: 0.9–1.9) for DXA, together with similar receiver operating
characteristics curves, were found using age-adjusted logistic regression. Phalangeal BMD is related to vertebral deformities
at least as closely as BMD of the femoral neck BMD. RA may therefore help to evaluate fracture risk, especially if no DXA
equipment is available.
Received: 21 July 1998 / Accepted: 1 July 1999 相似文献
52.
Riluzole and methylprednisolone combined treatment improves functional recovery in traumatic spinal cord injury 总被引:6,自引:0,他引:6
The potential use of riluzole (a glutamate release inhibitor) alone or in combination with methyl-prednisolone (MP) in treating acute spinal cored injury (SCI) was examined. Rats received a contusion injury to the spinal cord using the NYU impactor and were treated with vehicle, riluzole (8 mg/kg), MP(30 mg/kg), or riluzole + MP at 2 and 4 h following injury. Animals continued to receive riluzole treatment (8 mg/kg) for a period of 1 week. The animals were then tested weekly for functional recovery using the BBB open field locomotor score. At the end of testing (6 weeks after injury), each spinal cord was examined for the amount of remaining tissue at the injury site and a myelination index was used to quantify remaining axons in the ventromedial white matter. In this study, only the combination treatment was found to significantly improve behavioral recovery as assessed using the BBB open field locomotor scale. In addition, the combination treatment promoted tissue sparing at the lesion epicenter, but had no clear effect on the index of myelination. The results of this study clearly demonstrate the potential beneficial effects of a combination approach in the treatment of traumatic SCI. 相似文献
53.
PC NG KW SO TF FOK MC YAM MY WONG W WONG 《Journal of paediatrics and child health》1997,33(4):324-328
Objectives: A prospective study comparing the efficiacy and side-effects of oral sulindac with intravenous indomethacin in clinically stable preterm infants (<1750 g) requiring non-invasive closure of haemodynamically significant patent ductus arteriosus.
Methodology: As maturity and birthweight are the two major determinants of ductal closure, infants were matched as closely as possible for these parameters. An eligible patient was first assigned to the sulindac group and a subsequent patient with similar gestational age (± 1 week) and birthweight (±100 g) to the previously recruited infant would automatically receive indomethacin. A total of eight infants were enrolled in each group.
Results: The ductus arteriosus was successfully closed in all eight infants receiving indomethacin, and in seven of eight infants receiving sulindac. No significant differences were found with regards to the ductal size between the two groups at diagnosis or on each of the consecutive days of treatment ( P >0.25). More renal adverse effects were encountered in the indomethacin group. Significant differences in changes from baseline value for urine output, plasma sodium, urea and creatinine concentrations were noted at 24, 48 and 72 h after commencement of treatment between the two groups ( P <0.05). All the parameters returned to normal or pre-treatment levels 48 h after stopping therapy. Unexpectedly, severe gastrointestinal complications were encountered in the sulindac group.
Conclusions: Sulindac is capable of promoting ductal constriction in clinically stable preterm infants without compromising the renal function. The spectrum of gastrointestinal complications observed in sulindac treated infants were similar to those described for indomethacin. The use of sulindac for ductal closure in the preterm infant should remain experimental. 相似文献
Methodology: As maturity and birthweight are the two major determinants of ductal closure, infants were matched as closely as possible for these parameters. An eligible patient was first assigned to the sulindac group and a subsequent patient with similar gestational age (± 1 week) and birthweight (±100 g) to the previously recruited infant would automatically receive indomethacin. A total of eight infants were enrolled in each group.
Results: The ductus arteriosus was successfully closed in all eight infants receiving indomethacin, and in seven of eight infants receiving sulindac. No significant differences were found with regards to the ductal size between the two groups at diagnosis or on each of the consecutive days of treatment ( P >0.25). More renal adverse effects were encountered in the indomethacin group. Significant differences in changes from baseline value for urine output, plasma sodium, urea and creatinine concentrations were noted at 24, 48 and 72 h after commencement of treatment between the two groups ( P <0.05). All the parameters returned to normal or pre-treatment levels 48 h after stopping therapy. Unexpectedly, severe gastrointestinal complications were encountered in the sulindac group.
Conclusions: Sulindac is capable of promoting ductal constriction in clinically stable preterm infants without compromising the renal function. The spectrum of gastrointestinal complications observed in sulindac treated infants were similar to those described for indomethacin. The use of sulindac for ductal closure in the preterm infant should remain experimental. 相似文献
54.
55.
Janet Martin Stephen M. Stribbling Grace K. Poon Richard H. J. Begent Mark Napier Surinder K. Sharma C. J. Springer 《Cancer chemotherapy and pharmacology》1997,40(3):189-201
Antibody-directed enzyme prodrug therapy (ADEPT) was administered to ten patients in a phase I clinical trial. The aim was
to measure plasma levels of the prodrug 4-[(2-chloroethyl)(2-mesyloxyethyl) amino] benzoyl-l-glutamic acid (CMDA) and the bifunctional alkylating drug (CJS11) released from it by the action of tumour-localised carboxypeptidase
G2 (CPG2) enzyme. New techniques were developed to extract the prodrug and drug from plasma by solid-phase adsorbtion and
elution and to measure CPG2 activity in plasma and tissue. All extracts were analysed by high-performance liquid chromatography
(HPLC) and liquid chromatography-mass spectrometry (LC-MS). CPG2 activity was found in metastatic tumour biopsies but not
in normal tissue, indicating that localisation had been successful. The clearing agent SB43-gal, given at 46.5 mg/m2, achieved the aim of clearing non-tumour-localised enzyme in the circulation, indicating that conversion of prodrug to drug
could take place only at the site of localised conjugate. Plasma prodrug did not always remain above its required threshold
of 3 μM for the “therapeutic window” of 120 min after dosing, but the presence of residual prodrug after the first administration
of each day indicated that this could be achieved during the remaining four doses over the following 8 h. Despite considerable
inter-patient prodrug plasma concentration variability, the elimination half-life of the prodrug was remarkably reproducible
at 18 ± 8 min. Rapid appearance of the drug in plasma indicated that successful conversion from the prodrug had taken place,
but also undesirable leakback from the site of localisation into the bloodstream. However, drug plasma levels fell rapidly
by at least 50% at between 10 and 60 min with a half-life of 36 ± 14 min. Analysis of the plasma extracts by LC/MS indicated
that this technique might be used to confirm qualitatively the presence of prodrug, drug and their metabolites.
Received: 21 July 1996 / Accepted: 20 January 1997 相似文献
56.
Virtual computed tomography colonoscopy: artifacts, image quality and radiation dose load in a cadaver study 总被引:2,自引:0,他引:2
Springer P Stöhr B Giacomuzzi SM Bodner G Klingler A Jaschke W zur Nedden D 《European radiology》2000,10(1):183-187
The purpose of our study was to evaluate the interdependency of spatial resolution, image reconstruction artifacts, and radiation
doses in virtual CT colonoscopy by comparing various CT scanning protocols. A pig's colon with several artificial polypoid
lesions was imaged after air insufflation with helical CT scanning using 1-, 3-, and 5-mm collimation, and pitch values varying
from 1.0 to 3.0. Virtual endoscopic images and “fly through” sequences were calculated on a Sun Sparc 20 workstation (Navigator
Software, GE Medical Systems, Milwaukee, Wis.). Several reconstruction artifacts as well as overall image quality were evaluated
by three independent reviewers. In addition, radiation doses for the different CT protocols were measured as multiple-scan
average dose using a 10-cm ion chamber and a standard Plexiglass body phantom. Generally, image quality and reconstruction
artifacts were less affected by pitch values than by beam collimation. Thus, narrow beam collimation at higher pitch values
(e. g. 3 mm/2.0) seems to be a reasonable compromise between quality of virtual endoscopic images and radiation dose load.
Received: 4 February 1999; Revised: 16 June 1999; Accepted: 17 June 1999 相似文献
57.
58.
59.
60.