全文获取类型
收费全文 | 4052篇 |
免费 | 339篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 89篇 |
妇产科学 | 51篇 |
基础医学 | 618篇 |
口腔科学 | 50篇 |
临床医学 | 428篇 |
内科学 | 976篇 |
皮肤病学 | 53篇 |
神经病学 | 367篇 |
特种医学 | 149篇 |
外科学 | 641篇 |
综合类 | 45篇 |
一般理论 | 3篇 |
预防医学 | 273篇 |
眼科学 | 77篇 |
药学 | 243篇 |
中国医学 | 9篇 |
肿瘤学 | 255篇 |
出版年
2023年 | 35篇 |
2022年 | 51篇 |
2021年 | 161篇 |
2020年 | 63篇 |
2019年 | 120篇 |
2018年 | 157篇 |
2017年 | 100篇 |
2016年 | 89篇 |
2015年 | 111篇 |
2014年 | 144篇 |
2013年 | 187篇 |
2012年 | 312篇 |
2011年 | 346篇 |
2010年 | 145篇 |
2009年 | 122篇 |
2008年 | 237篇 |
2007年 | 227篇 |
2006年 | 200篇 |
2005年 | 172篇 |
2004年 | 153篇 |
2003年 | 111篇 |
2002年 | 127篇 |
2001年 | 73篇 |
2000年 | 72篇 |
1999年 | 48篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 27篇 |
1995年 | 20篇 |
1994年 | 34篇 |
1993年 | 24篇 |
1992年 | 52篇 |
1991年 | 45篇 |
1990年 | 52篇 |
1989年 | 41篇 |
1988年 | 31篇 |
1987年 | 47篇 |
1986年 | 28篇 |
1985年 | 34篇 |
1984年 | 20篇 |
1983年 | 27篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 30篇 |
1979年 | 30篇 |
1978年 | 20篇 |
1976年 | 15篇 |
1975年 | 18篇 |
1973年 | 15篇 |
1972年 | 14篇 |
排序方式: 共有4396条查询结果,搜索用时 15 毫秒
1.
2.
Ferdynand Hebal Elissa Port Catherine J. Hunter Bryan Malas Jared Green Marleta Reynolds 《Journal of pediatric surgery》2019,54(4):656-662
Background/purpose
Computed tomography (CT) derived Haller Index (HI) remains the standard for quantifying severity in patient with pectus excavatum (PE). Optical scanning described in literature reports optimistic results and new indices that correlate with HI. This study assessed the feasibility of a handheld White Light Scanner (WLS) to obtain 3D measurements and indices of PE deformity.Methods
From April 2015–April 2017, WLS scanning was conducted by orthotists during clinical visits. Included were children with PE up to 18?years. Analysis assessed correlation of a WLS-derived severity index, Hebal-Malas Index (HMI), with physician measured PE Depth (PED), and CT-derived HI.Results
Of 195 participants, 185(94%) patients with PE were scanned and 127(69%) had complete WLS data. For 88 patients undergoing monitoring, HMI correlated with PED (r?=?0.42, p?=?0.004). For 39 patients with pre-operative CT, HMI demonstrated strong correlation with HI (r?=?0.87, p < 0.0001).Conclusions
WLS demonstrated high feasibility of scanning PE. WLS-derived HMI best correlates with HI for patients with severe pectus deformity. Our current data is suggestive that WLS is best applied for severe deformities and yet to be established for milder deformities. Future yearly WLS will provide data on deformity progression and surgical therapy.Level of Evidence
IV.Type of Study
Diagnostic Study. 相似文献3.
Joseph M Dhahbi Shelley X Cao Patricia L Mote Brian C Rowley John E Wingo Stephen R Spindler 《The Journal of nutrition》2002,132(1):31-37
Molecular chaperones assist in the biosynthesis and processing of proteins. Most chaperones are induced by physiological stresses. We have shown that dietary energy restriction decreases the mRNA and protein levels of many endoplasmic reticulum chaperones in the livers of mice. Here, we have investigated the response of chaperone mRNA to feeding. Control and 50% energy-restricted C3B10RF1 mice were deprived of food for 24 h, fed, and killed 0, 1.5, 5 or 12 h after feeding. Chaperone mRNAs were strongly induced as early as 1.5 h after feeding in control and energy-restricted mice. The integrated levels of these mRNA over 24 h were significantly lower in energy-restricted mice. The mRNA response to energy intake was mirrored over the course of days in the level of chaperone protein. A similar but smaller response to feeding was found in kidney and muscle. Puromycin and cycloheximide failed to inhibit the feeding response, suggesting that feeding releases chaperone expression from an unstable inhibitor. Studies with dibutyryl-cAMP- and glucagon-supplemented, normal and streptozotocin-diabetic mice suggest that glucagon and insulin may be mediators of the feeding response. Adrenalectomy enhanced the feeding induction, but dexamethasone administration had no effect. Thus, postprandial changes in insulin and glucagon may link chaperone gene expression to feeding, possibly in several tissues including liver. 相似文献
4.
Predicting failure in polytetrafluoroethylene vascular access grafts for hemodialysis: a pilot study
C R Shackleton D C Taylor A R Buckley V A Rowley P L Cooperberg P D Fry 《Canadian journal of surgery》1987,30(6):442-444
In order to determine if serial, noninvasive evaluation of polytetrafluoroethylene (PTFE) vascular access grafts could identify a subgroup of patients at risk for thrombosis, the authors studied flow characteristics, using duplex ultrasonic scanning, in 18 hemodialysis patients with forearm loop grafts. On average, five examinations were performed per patient over the 10-month study period. Seven episodes of thrombosis occurred in six patients. The mean Doppler flow in grafts that subsequently thrombosed was significantly lower than in those that did not (544 +/- 218 ml/min versus 843 +/- 391 ml/min, p less than 0.001). The interval from last examination to thrombosis ranged from 13 to 58 days. At a defined cut-off flow of 450 ml/min, this test yielded a sensitivity of 83% and a specificity of 75% for episodes of thrombosis occurring within 2 to 6 weeks. The authors conclude that episodes of thrombosis in PTFE arm loop grafts are usually preceded by significantly lower Doppler-measured flow than grafts that do not thrombose and that it may be possible, by this means, to identify grafts at risk. 相似文献
5.
Association of Hypoalbuminemia on the First Postoperative Day and Complications Following Esophagectomy 总被引:1,自引:0,他引:1
Aoife M. Ryan Aine Hearty Ruth S. Prichard Aileen Cunningham Suzanne P. Rowley John V. Reynolds 《Journal of gastrointestinal surgery》2007,11(10):1355-1360
Objective Changes in serum albumin may reflect systemic immunoinflammation and hypermetabolism in response to insults such as trauma
and sepsis. Esophagectomy is associated with a major metabolic stress, and the aim of this study was to determine if the absolute
albumin level on the first postoperative day was of value in predicting in-hospital complications.
Methods A retrospective study of 200 patients undergoing esophagectomy for malignant disease at St. James Hospital between 1999 and
2005 was performed. Patients who had pre and postoperative (days 1, 3, and 7) serum albumin levels measured were included
in the study. Patients were subdivided into three postoperative albumin categories <20 g/l, 20–25 g/l, >25 g/l. Logistic regression
analysis was performed to calculate the odds of morbidity and mortality according to the day 1 albumin level.
Results Patients with an albumin of less than 20 g/l on the first postoperative day were twice as likely to develop postoperative
complications than those with an albumin of greater than 20 g/l (54 vs 28% respectively, p < 0.011). Correspondingly, these patients also had a significantly higher rate of Adult Respiratory Distress Syndrome (22
vs 5%, p < 0.001), respiratory failure (27 vs 8%, p < 0.01) and in-hospital mortality (27 vs 6% (p < 0.001). On multivariate logistic regression analysis, day 1 albumin level was independently related to postoperative complications
(odds ratios, 0.89: 95%; confidence intervals, 0.83–0.96; p < 0.005). In addition, albumin <20 g/l on the first postoperative day was associated with the need for further surgery and
a return to ICU.
Conclusion Serum albumin concentration on the first postoperative day is a better predictor of surgical outcome than many other preoperative
risk factors. It is a low cost test that may be used as a prognostic tool to detect the risk of adverse surgical outcomes. 相似文献
6.
Cardiac imaging in the evaluation of patients presenting to the emergency department with chest pain
Conclusions Despite the utility and benefits that each imaging modality has to offer, it is easy to see why there is still no perfect
choice for a noninvasive cardiac imaging modality to assist in the management of chest pain patients. All of the current imaging
techniques have their own significant strengths and weaknesses when compared with other modalities. SPECT and echocardiography
are wellestablished technologies that can directly assess the presence of myocardial ischemia and its functional consequence
on RF; newer and more expensive techniques such as MDCT and CMR can directly assess coronary anatomy and have just started
to be evaluated in the acute chest pain setting. There are no studies that directly compare these technologies, and more data
are clearly needed before the question of whether anatomic imaging versus perfusion/function imaging is the better approach
can be answered. Other comparisons such as relative safety, availability, logistics, and cost-effectiveness between the various
technologies are also lacking.
Of all of the imaging modalities discussed, MCE is the only portable technology. The images do not require expensive software
or other technology for offline processing before interpretation, and any trained cardiologist can read the study at the bedside
or, potentially, over the Internet, providing near-instantaneous results in the acute cardiac setting, where time is of the
essence.
MCE is also relatively cheap compared with other technologies, a potential advantage for payors but not necessarily for payees.
How reimbursement rates and fee structures eventually affect clinical practice is also unknown.
Despite these and other questions that need to be answered before any one technique will be used exclusively, the future of
noninvasive cardiac imaging remains an exciting and ever-changing field. The adaptation of any one of these techniques into
its proper role in the ED Journal of Nuclear Cardiology Wyrick and Wei 753 Volume 13, Number 6;749-55 Cardiac imaging in patients
with chest pain will take considerably more time and effort in terms of research, money, and time-tested clinical experience. 相似文献
7.
Pawan Kumar Dhruva Rao Deborah Clements Michael M. Davies Jared Torkington 《Surgical endoscopy》2007,21(6):1036
We present our comments on the above article. 相似文献
8.
9.
Radiotherapy has been successful in treating localized prostate cancer; however, a subset of patients will experience disease
recurrence. Determination of the recurrence location must be made using pretreatment and posttreatment clinical variables,
imaging, and postradiotherapy biopsy. Patients presumed to have local-only recurrence, optimal clinical risk factors, and
an extended life expectancy may be considered for salvage local treatment. Current options include salvage surgery, cryoablation,
and brachytherapy. Although they are associated with higher morbidity than primary therapy, salvage treatments can be effective
and can still provide patients with a good oncologic and functional outcome. As these modalities continue to improve and patient
selection is optimized, better results will evolve. 相似文献
10.
Moh H Malek Dale E Berger William D Marelich Jared W Coburn Travis W Beck Terry J Housh 《European journal of cardio-thoracic surgery》2006,30(4):637-643
The purpose of this study was to use a meta-analytical technique to examine the efficacy of surgical repair of pectus excavatum on pulmonary function. Studies were retrieved via computerized literature searches, cross-referencing from original and review articles. Inclusion criteria were as follows: (1) reporting quantitative measures of preoperative and postoperative pulmonary function; (2) published in the English language; (3) indexed between January 1960 and September 2005; (4) reporting the duration between which preoperative and postoperative assessments were conducted; and (5) describing the pulmonary assessment procedures. The titles and abstracts of potentially relevant articles were reviewed to determine whether they met the criteria for inclusion. Twelve studies representing 313 pectus excavatum patients met the inclusion criteria and were used for the meta-analysis. Random-effects modeling yielded a mean weighted effect size (ES) for pulmonary function which was statistically nonsignificant (ES=0.08, 95% CI=-0.20 to 0.35; P=0.58). The findings of the present study indicated that surgical repair of pectus excavatum does not significantly improve pulmonary function. These findings, however, may be a result of testing pulmonary function under conditions in which pectus excavatum does not manifest itself. 相似文献