全文获取类型
收费全文 | 1395篇 |
免费 | 117篇 |
国内免费 | 96篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 102篇 |
妇产科学 | 7篇 |
基础医学 | 124篇 |
口腔科学 | 29篇 |
临床医学 | 169篇 |
内科学 | 262篇 |
皮肤病学 | 8篇 |
神经病学 | 81篇 |
特种医学 | 173篇 |
外科学 | 232篇 |
综合类 | 49篇 |
预防医学 | 116篇 |
眼科学 | 22篇 |
药学 | 117篇 |
肿瘤学 | 107篇 |
出版年
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 19篇 |
2015年 | 22篇 |
2014年 | 37篇 |
2013年 | 48篇 |
2012年 | 46篇 |
2011年 | 40篇 |
2010年 | 44篇 |
2009年 | 46篇 |
2008年 | 36篇 |
2007年 | 104篇 |
2006年 | 41篇 |
2005年 | 76篇 |
2004年 | 38篇 |
2003年 | 44篇 |
2002年 | 36篇 |
2001年 | 44篇 |
2000年 | 39篇 |
1999年 | 32篇 |
1998年 | 50篇 |
1997年 | 43篇 |
1996年 | 38篇 |
1995年 | 35篇 |
1994年 | 37篇 |
1993年 | 48篇 |
1992年 | 23篇 |
1991年 | 34篇 |
1990年 | 39篇 |
1989年 | 66篇 |
1988年 | 43篇 |
1987年 | 32篇 |
1986年 | 34篇 |
1985年 | 34篇 |
1984年 | 19篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 18篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1972年 | 7篇 |
1966年 | 5篇 |
排序方式: 共有1608条查询结果,搜索用时 265 毫秒
1.
Brief review: History, concept and controversies in the neurological determination of death 总被引:1,自引:0,他引:1
Leonard Baron Sam D. Shemie Jeannie Teitelbaum Christopher James Doig 《Journal canadien d'anesthésie》2006,53(6):602-608
PURPOSE: Despite general worldwide acceptance of the concept of neurological determination of death (NDD), inconsistencies in clinical criteria and ancillary testing requirements remain. Numerous guidelines for NDD may be applied in clinical practice by a variety of medical practitioners, but the scientific rationale for specific guideline recommendations often remains unclear. This review examines the evolution of NDD, and seeks to provide scientific validation for existing NDD criteria. SOURCE: English language peer-reviewed medical journals and established contemporary medical texts. PRINCIPAL FINDINGS: Currently published guidelines appear to have evolved from the work of the ad hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death. The Conference of the Royal Colleges and Faculties of the United Kingdom refined the criteria and subsequently adopted the principal of brainstem death. While the fundamentals of NDD guidelines are remarkably consistent worldwide, specific criteria and requirements are often inconsistent. CONCLUSION: Numerous controversies regarding NDD continue to exist, necessitating further scientific clarification of these issues. More recently published guidelines representing the collective opinion of world experts in NDD based upon best current scientific evidence are available in current medical journals. 相似文献
2.
顺铂聚乳酸微球的药物释放特性及肝动脉栓塞研究 总被引:5,自引:0,他引:5
对顺铂聚乳酸微球进行了体外药物释放和家犬肝动脉栓塞研究。该微球粒径范围为50~200μm,平均粒径为115.76±35.94μm,顺铂含量为37.16%(W/W);体外药物释放机制符合Higuchi方程;肝动脉栓塞后8h,肝组织顺铂浓度高达21.55±12.18μg/g,明显高于肝动脉灌注顺铂组:3.16±0.09μg/g(P<0.05);肝动脉栓塞组的顺铂血浓峰值、各取血点浓度及曲线下面积AUC皆低于肝动脉灌注顺铂组。可望达到提高栓塞部位的药物疗效,降低全身毒副反应的作用。 相似文献
3.
PC Chamyal A Mehta SL Ojha JR Bhardwaj 《Indian journal of otolaryngology and head and neck surgery》1991,43(1):26-27
Primary tuberculous pathology in nasolpolypi is a rare condition. A case of bilateral ethmoidal polypi with tubercular lesion diagnosed on histopathologlcal examination is being reported and the available relevant literature has been reviewed. 相似文献
4.
5.
BACKGROUND: Many patients with asthma or chronic obstructive pulmonary diseaseuse their medication inhalers incorrectly. General practitioners,pharmacists and other health care providers do not always havethe opportunity to instruct patients in correct inhaler technique. OBJECTIVE: To find out whether the inhaler technique and respiratory symptomsof patients can be improved after instruction by practice assistants. METHODS: Single blind, randomized intervention study in which 48 patientswho had been using a dry powder inhaler for at least one monthtook part. Their inhaler technique was videotaped on two visitswith a two-week interval between visits. The inhaler techniqueon the videos was subsequently scored by two experts on ninecriteria. At both visits the patients completed a questionnaireabout their respiratory symptoms. After the first video, 25patients were randomly chosen to receive instruction from oneof six practice assistants who had followed a one evening courseabout inhaler instruction, and who had been issued an instruction-set. RESULTS: The patients who received instruction had a significantly greaterreduction in number of mistakes at the second visit than thepatients who did not (P = 0.01). The instructed patients alsoreported less dyspnoea at the second visit (P = 0.03). No effectof instruction was found on wheezing, cough and sputum production. CONCLUSION: The inhaler technique of patients can be improved significantlyby the instruction of patients by trained practice assistants,possibly resulting in less dyspnoea. Keywords. Administration-inhalation, obstructive lung diseases, airways symptoms, patient-education, general practice. 相似文献
6.
Kinnison ML; Perler BA; Kaufman SL; Mitchell SE; Kadir S; Williams GM; White RI Jr 《Radiology》1986,160(3):727-730
In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications. 相似文献
7.
Zvi Bar-Shavit Ronald L. Horst Jean C. Chappel F. Patrick Ross Richard W. Gray Steven L. Teitelbaum M.D. 《Calcified tissue international》1986,39(5):328-333
Summary 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a potent inducer of monocytic differentiation of the human promyelocytic leukemia cell line, HL-60. We have noted that
25-hydroxyvitamin D3 (25(OH)D3) in high doses is also capable of promoting monocytic differentiation of this cell line. To test the possibility that the
latter activity is due to conversion of 25OHD3 to 1,25(OH)2D3 by HL-60, we exposed HL-60 cells to 25OHD3 and analyzed the products by HPLC and radioreceptor assay. When chromatographed in the traditional solvent system (isopropanol-hexane),
a new peak appears which migrates with authentic 1,25(OH)2D3. However, in a solvent system containing dichloromethane, 90% of the peak migrates with another metabolite, 19-Nor-10-Keto-25OHD3 (19-Nor-25OHD3). Production of this metabolite is enhanced by living cells and is synthesized by both virgin HL-60 and those which have
undergone differentiation. We next determined if authentic 19-Nor-25OHD3 also promotes differentiation of this cell. As assessed by appearance of the monocyte-specific surface antigen (63D3) and
macrophage-specific esterase activity, we find that this metabolite does, in fact, induce monocytic differentiation of HL-60
with a potency of approximately 1/200 that of 1,25(OH)2D3 and similar to that of 25OHD3. In agreement with the effect upon cell maturation, 19-Nor-25OHD3 displaces3H-1,25(OH)2D3 from its HL-60 receptor with an efficiency comparable to 25OHD3. Hence, HL-60 cells convert 25OHD3 to 19-Nor-25OHD3, and 19-Nor-25OHD3 induces monocytic differentiation of HL-60 with comparable efficiency to its precursor, 25OHD3. 相似文献
8.
Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance 总被引:3,自引:0,他引:3
Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy. 相似文献
9.
Use of abdominal ultrasonography to assess pediatric splenic trauma. Potential pitfalls in the diagnosis. 总被引:4,自引:2,他引:2 下载免费PDF全文
A S Krupnick D H Teitelbaum J D Geiger P J Strouse C S Cox C E Blane T Z Polley 《Annals of surgery》1997,225(4):408-414
OBJECTIVE: The purpose of this study was to evaluate the accuracy of abdominal ultrasonography (US) for screening and grading pediatric splenic injury. SUMMARY BACKGROUND DATA: The use of abdominal US has increased rapidly as a method of evaluating organ damage after blunt abdominal trauma. Despite US's increasing use, little is known about its accuracy in children with splenic injury. METHODS: Children (N = 32) suffering blunt abdominal trauma who were diagnosed with splenic injury by computerized tomography (CT) scan prospectively were enlisted in this study. Degree of splenic injury was evaluated by both CT and US. The ultrasounds were evaluated by an initial reading as well as by a radiologist who was blinded as to the results of the CT. RESULTS: Twelve (38%) of the 32 splenic injuries found on CT were missed completely on the initial reading of the US. When the ultrasounds were graded in a blinded fashion, 10 (31%) of the splenic lacerations were missed and 17 (53%) were downgraded. Seven (22%) of the 32 splenic fractures were not associated with any free intraperitoneal fluid on the CT scan. CONCLUSIONS: This study has shown that US has a low level of sensitivity (62% to 78%) in detecting splenic injury and downgrades the degree of injury in the majority of cases. Reliance on free intraperitoneal fluid may be inaccurate because not all patients with splenic injury have free intra-abdominal fluid. Based on these findings, US may be of limited use in the initial assessment, management, and follow-up of pediatric splenic trauma. 相似文献
10.
S A Teitelbaum E W Fonkalsrud 《The Journal of thoracic and cardiovascular surgery》1988,96(1):162-165
This article presents the case of a child with an unusual type of cleft sternum characterized by fusion superiorly between the clavicles and inferiorly at the xiphoid with wide intervening separation. The defect was successfully corrected at age 17 months by surgical closure of the cleft primarily, which had not been achieved previously in a patient at this late age. 相似文献