全文获取类型
收费全文 | 7726篇 |
免费 | 737篇 |
国内免费 | 62篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 254篇 |
妇产科学 | 202篇 |
基础医学 | 1030篇 |
口腔科学 | 204篇 |
临床医学 | 762篇 |
内科学 | 1486篇 |
皮肤病学 | 249篇 |
神经病学 | 477篇 |
特种医学 | 477篇 |
外科学 | 774篇 |
综合类 | 90篇 |
一般理论 | 2篇 |
预防医学 | 969篇 |
眼科学 | 156篇 |
药学 | 562篇 |
中国医学 | 13篇 |
肿瘤学 | 698篇 |
出版年
2022年 | 48篇 |
2021年 | 98篇 |
2020年 | 84篇 |
2019年 | 129篇 |
2018年 | 141篇 |
2017年 | 111篇 |
2016年 | 139篇 |
2015年 | 158篇 |
2014年 | 177篇 |
2013年 | 246篇 |
2012年 | 357篇 |
2011年 | 295篇 |
2010年 | 215篇 |
2009年 | 222篇 |
2008年 | 317篇 |
2007年 | 378篇 |
2006年 | 356篇 |
2005年 | 346篇 |
2004年 | 292篇 |
2003年 | 280篇 |
2002年 | 258篇 |
2001年 | 229篇 |
2000年 | 245篇 |
1999年 | 222篇 |
1998年 | 160篇 |
1997年 | 160篇 |
1996年 | 155篇 |
1995年 | 127篇 |
1994年 | 122篇 |
1993年 | 108篇 |
1992年 | 145篇 |
1991年 | 175篇 |
1990年 | 176篇 |
1989年 | 176篇 |
1988年 | 186篇 |
1987年 | 148篇 |
1986年 | 141篇 |
1985年 | 146篇 |
1984年 | 107篇 |
1983年 | 76篇 |
1982年 | 61篇 |
1981年 | 61篇 |
1979年 | 82篇 |
1978年 | 60篇 |
1977年 | 55篇 |
1976年 | 60篇 |
1975年 | 67篇 |
1974年 | 56篇 |
1973年 | 54篇 |
1972年 | 44篇 |
排序方式: 共有8525条查询结果,搜索用时 15 毫秒
41.
Summary Total parotidectomy causes a significant postoperative concave deformity in the retromandibular, preauricular, and infra-auricular regions of the face; many patients are concerned about this defect. Frey's syndrome (gustatory sweating) is also a well-recognized postoperative entity following parotid surgery. The incidence of Frey's syndrome ranges from 10–90%, depending on the type and complexity of the investigation used to diagnose it [5, 11]. Numerous methods have been described to correct these problems. Patients requiring total parotidectomy were recently offered the option of immediate reconstruction of the contour defect with microvascular transfer of a tailored gracilis muscle flap. Four patients are included in this preliminary series; all are extremely satisfied with the postoperative result. The defect following total parotidectomy can be reconstructed immediately with gratifying cosmetic results, a hidden donor site scar, and to date no operative morbidity. 相似文献
42.
Pernes JM; Vitoux JF; Brenoit P; Raynaud A; Parola JL; Roth JP; Angel CY; Fiessinger JN; Roncato M; Gaux JC 《Radiology》1986,158(2):481-485
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs. 相似文献
43.
OBJECTIVE: This study proposes a method for self-report health questionnaires to adjust test-retest reliability for changes during the test-retest interval based on an external measure, and to distinguish such changes from random response errors. METHODS: In our application, eighty participants completed the Symptoms of Illness Checklist (SIC) on two occasions, two weeks apart, immediately before interviews given on each occasion by one of two physicians in a crossover design. The physician interview scores served as external measures, and structural equation modeling was used to estimate the parameters of a model that corrected for the occasion-specific effect of participants' responses using information from the interviews. RESULTS: Correcting for changes in symptoms during the test-retest interval increased SIC test-retest reliability from .744 to .804 and significantly improved model fit (chi2(diff)(1) = 30.78, p < .001). CONCLUSIONS: The results suggest methods that can improve the evaluation of self-report health questionnaire test-retest reliability by identifying changes using an external measure, and distinguishing these from random response errors; these increased the estimated SIC test-retest reliability and indicated that the SIC was indeed able to measure changes over the studied time interval. This method can be applied across a broad range of questionnaires. 相似文献
44.
Interobserver variation in the evaluation of neurological signs: observer dependent factors. 总被引:2,自引:0,他引:2
M. Hansen S.H. Sindrup P.B. Christensen N.K. Olsen O. Kristensen M.L. Friis 《Acta neurologica Scandinavica》1994,90(3):145-149
Introduction - Interobserver variation among four observers in evaluation of eight selected neurological signs was investigated. Material & methods - Two hundred and two consecutive unselected inpatients were examined by two senior neurologists and two trainees, all without knowledge of the neurological case history. The signs examined were: anisocoria, jerky eye movements, facial palsy, elbow extension force, finger-nose test, Barré sign, knee jerk, and extensor plantar reflex. Observed agreement rates and kappa coefficients were calculated in order to compare the interobserver variability among neurologists and trainees, and to evaluate differences in the interobserver variability between signs. Results - Observed agreement rates varied from 0.80 to 0.95 for neurologists and from 0.65 to 0.98 for trainees. For neurologists kappa coefficients ranged from 0.40 to 0.67 and for trainees from 0.22 to 0.81. The neurologists had higher kappa values than the trainees in 5 signs, but this difference was only statistically significant for jerky eye movements. For the individual signs the observed agreement rates were between 0.50 and 0.93 for all four examiners combined, and overall kappa values varied from 0.32 to 0.71 with highest agreement for facial palsy and lowest for knee jerk. Conclusion - The magnitude of the interobserver and intersign variation indicates that the interpretation of the neurological signs tested, without knowledge of the case history, should be done with some caution. 相似文献
45.
H. C. Lou P. B. Toft J. Andresen I. Mikkelsen B. Olsen F. Güttler S. Wieslander O. Henriksen 《Journal of inherited metabolic disease》1992,15(5):687-695
Summary The study included 16 adolescents with optimally controlled hyperphenylalaninaemia (McKusick 26160), of whom six did not require treatment according to conventional criteria. All except the two patients with lowest median serum phenylalanine level throughout childhood (most values at 200–300 µmol/L) had white matter abnormalities detectable with magnetic resonance imaging. The lesions were particularly prominent in the watershed regions between the posterior and middle cerebral arteries. In most patients with moderate or severe hyperphenylalaninaemia frontal white matter lesions were present as well. Normal proton magnetic resonance spectra indicated that the lesions were stable. Occipital EEG abnormalities were frequent, and deficient performance on a pattern-recognition test was a characteristic neuropsychological finding. Serum phenylalanine levels at about 300 µmol/L or below throughout childhood and early adolescence may be required to avoid lesions. The present study demonstrates the limitations of even an optimally controlled dietary regimen in hyperphenylalaninaemia. 相似文献
46.
Brandon JC; Teplick SK; Haskin PH; Sammon JK; Muhr WF; Hofmann AF; Gambescia RA; Zitomer N 《Radiology》1988,166(3):665-667
The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control. 相似文献
47.
Ultrasound (US) can be used to visualize vertebral segments, suggesting a quantitative means of studying vertebral column growth in utero and thus a means of detecting developmental abnormalities. US images of the lumbar spine were obtained in 128 clinically normal fetuses between the gestational age of 11 through 41 weeks. A large-aperture, dynamically focused US system capable of regional magnification was used. Average lumbar spacing was calculated from distance between centrums of at least four lumbar bodies. The average distance between lumbar centrums increased nearly linearly throughout the second and third trimesters (r2 = 0.98). Enhanced anatomic display implies new capabilities for recognizing developmental abnormalities antenatally. 相似文献
48.
49.
M P Schweizer J I Olsen J Shelby J R Saffle L R Chick M Meyer J Sylvester P Jensen T L Nagel 《The Journal of trauma》1992,33(6):828-834
Phosphorus-31 nuclear magnetic resonance techniques using shallow penetrating coils have been used to noninvasively monitor severity and metabolic changes over time in skin wounds in rats. Ratios of phosphocreatine (PCr) to inorganic phosphate (Pi) indicate energy status in both thermal wounds and surgical flaps. In partial and full-thickness scald wounds, reductions in PCr/Pi ratios correlated with burn depth and improved over time postinjury, suggesting wound revascularization. No decrease in intracellular pH was noted in these wounds; the phosphate shifts may be primarily the result of tissue degradation followed by restoration of the microvasculature. Distal regions of caudally based dorsal 3 x 10 cm full-thickness skin flaps reveal progressively lower PCr/Pi ratios to 3-6 hours after elevation as well as drops in pH up to 0.5 units, presumably as a result of anaerobic glycolysis in these tissues. After 24 hours, the intracellular pH returned to normal (7.1-7.2) and the PCr/Pi ratios approached 70%-90% of the well-perfused proximal regions within 3-7 days. These results indicate the establishment of a microvasculature from the underlying bed as the distal regions survive as free grafts. The data demonstrate the potential usefulness of the technique in noninvasive measurement of the biochemical response to injury and wound healing in living organisms. 相似文献
50.
S V Karwande D G Renlund S L Olsen W A Gay W E Richenbacher J A Hawkins R C Millar J D Marks 《The Annals of thoracic surgery》1992,54(6):1039-1045
Between March 1985 and December 1991, mediastinitis developed in 12 of 420 cardiac transplantation patients (2.8%). The mortality rate in this group of patients was 8.3% (1/12). Actuarial survival (1 year, 75%; and 5 years, 65%) was not significantly different from that of the group without mediastinitis (1 year, 88%; and 5 years, 75%). A higher percentage of the patients in the group with mediastinitis were listed as UNOS status 1 (50% versus 35%) and had a history of previous sternotomies (58% versus 44%). The presentation of mediastinitis was typical. Computed tomographic scanning with or without aspiration was a valuable adjunct in the diagnosis of mediastinitis. Induction immunotherapy with minimal steroids in the perioperative period was used in all patients. This may contribute to the patients' ability to mount an appropriate and effective response to infection, permitting earlier diagnosis. The debridement irrigation technique used in 8 of 12 patients had a low success rate of 33%, whereas the debridement muscle flap technique used in 4 of 12 was 100% successful in eliminating infection. 相似文献