全文获取类型
收费全文 | 19380篇 |
免费 | 1567篇 |
国内免费 | 52篇 |
学科分类
医药卫生 | 20999篇 |
出版年
2022年 | 149篇 |
2021年 | 386篇 |
2020年 | 227篇 |
2019年 | 356篇 |
2018年 | 428篇 |
2017年 | 268篇 |
2016年 | 360篇 |
2015年 | 407篇 |
2014年 | 513篇 |
2013年 | 819篇 |
2012年 | 1149篇 |
2011年 | 1077篇 |
2010年 | 663篇 |
2009年 | 631篇 |
2008年 | 1027篇 |
2007年 | 1034篇 |
2006年 | 931篇 |
2005年 | 1022篇 |
2004年 | 1039篇 |
2003年 | 964篇 |
2002年 | 868篇 |
2001年 | 351篇 |
2000年 | 363篇 |
1999年 | 346篇 |
1998年 | 220篇 |
1997年 | 166篇 |
1996年 | 168篇 |
1995年 | 174篇 |
1994年 | 146篇 |
1993年 | 158篇 |
1992年 | 260篇 |
1991年 | 240篇 |
1990年 | 254篇 |
1989年 | 258篇 |
1988年 | 231篇 |
1987年 | 201篇 |
1986年 | 207篇 |
1985年 | 231篇 |
1984年 | 190篇 |
1983年 | 146篇 |
1982年 | 158篇 |
1981年 | 157篇 |
1980年 | 138篇 |
1979年 | 134篇 |
1978年 | 101篇 |
1977年 | 111篇 |
1976年 | 126篇 |
1975年 | 108篇 |
1974年 | 139篇 |
1973年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Assessment of cardiovascular autonomic function. 总被引:5,自引:0,他引:5
Roy Freeman 《Clinical neurophysiology》2006,117(4):716-730
Autonomic assessment has played an important role in elucidating the role of the autonomic nervous system in diverse clinical and research settings. The techniques most widely used in the clinical setting entail the measurement of an end-organ response to a physiological provocation. The non-invasive measures of cardiovascular parasympathetic function involve the analysis of heart rate variability while the measures of cardiovascular sympathetic function assess the blood pressure response to physiological stimuli. Prolonged tilt-table testing, with or without pharmacological provocation, has become an important tool in the investigation of a predisposition to neurally mediated (vasovagal) syncope. Frequency domain analyses of heart rate and blood pressure variability, microneurography, occlusion plethysmography, laser Doppler imaging and flowmetry, and cardiac sympathetic imaging are currently research tools but may find a place in the clinical assessment of autonomic function in the future. 相似文献
62.
Michelle McKerral Pierre Lachapelle François Tremblay Robert C. Polomeno Marie-Sylvie Roy Raquel Beneish Franco Leporé 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(2):181-193
The contribution of each monocular pathway to the timing of the binocular pattern visual evoked potential was assessed in situations where a significant interocular timing discrepancy was observed. Monocular and binocular pattern visual evoked potentials to 0.5° checks were recorded from normal subjects, normal subjects in whom one eye was blurred, patients with monocular amblyopia, and patients with resolved unilateral optic neuritis. Normal subjects showed facilitation, while suppression was evidenced in subjects with monocular blurring. In patients with amblyopia, the affected pathway had no effect on binocular pattern visual evoked potential latency, suggesting that the amblyopic eye was suppressed. In contrast, all patients with optic neuritis showed binocular averaging. Our results show that different forms of binocular interaction are evidenced in normal subjects, in amblyopia and in optic neuritis, and suggest that a comparative analysis of monocular and binocular pattern visual evoked potential peak times brings valuable information to the clinical evaluation that could be used to distinguish disease processes further.Abbreviation BPVEP
binocular pattern visual evoked potential 相似文献
63.
K J Roy 《Clinics in Podiatric Medicine and Surgery》1988,5(3):491-508
Modern foot-pressure measurement studies have successfully debunked the tripod theory; on the contrary, the highest peak loads under the forefoot occur as often as not under the third metatarsal head and not the first and fifth. This does not necessarily mean that the first metatarsophalangeal joint does not sustain the highest pressures; calculations based on the measured pressures under the metatarsals and digits show that it does. One must bear in mind that the hallux consistently bears significantly more pressure than any of the other toes. It is likely that the pressure borne by the first metatarsal head and hallux combined consistently exceed that for the other four metatarsal heads and their respective digits. In other words, the first ray probably has the consistently highest load in normal feet, even when the second or third metatarsal head achieves a greater peak pressure than the first metatarsal head. Three lines of evidence suggest the role that pressure plays in forefoot pathology. First, metatarsalgia is commonly associated with hallux valgus. It often arises following or is exacerbated by hallux valgus surgery (especially arthroplastic procedures). Patients with hallux valgus demonstrate increased peak pressure under the lateral metatarsal heads that actually increases following the Keller procedure. Second, the peak pressure under callosities are, on the average, higher than normal. Third, diabetic plantar ulcers occur at sites of high pressure. The correlations between peak loads on the lateral column and both age and weight merit some attention, since it is common experience that the prevalence of symptomatic foot lesions is higher in older populations. The correlation with body weight may be unexpected. One would expect that, on the average, body weight would correlate with the weight-bearing surface area of the foot and, therefore, the pressure would be relatively constant. The increased pressure under the medial column suggests a relative instability of the medial column with advancing age and weight. Pressure should not be construed as the only factor. The large overlap in peak pressures found under diabetic ulcers and intact skin in both normal and diabetic feet makes this apparent. However, while peak pressures have been extensively studied, there has been no attempt to measure the duration or frequency of loading on a day-to-day basis. According to Brand, it is not the absolute loads applied to a part but repetitive pressure that is responsible for tissue breakdown, especially when such repetitive loads are applied without any interim period for the tissues to recover.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
64.
Depressed pathological gamblers 总被引:1,自引:0,他引:1
Depressed gamblers (n = 14) were compared with normal controls (n = 41) for antecedent life events. The depressed gamblers had experienced significantly more life events, and undesirable or exit life events, during the 6 months before the onset of depression. 相似文献
65.
Linda G. Rabinowitz M.D. Nancy B Esterly M.D. Ilona J. Frieden M.D. Gregory S. Garbin M.D. Roy C. Grekin M.D. T. J. Stafford M.D. Ph.D. O. T. Tan M.D. Linda G. Rabinowitz M.D. Gerald N. Goldberg M.D. Karen F Rothman M.D. Lynne J. Roberts M.D. Roy G. Geronemus M.D. Susan B. Mallory M.D. Jerome M. Garden M.D. Joseph G. Morelli M.D. Moise L Levy M.D. Bernard A. Cohen M.D. 《Pediatric dermatology》1992,9(2):132-153
One of the most exciting developments in pediatric dermatology has been the use of the flashlamp-pumped, 585-nm, pulsed dye laser for treatment of vascular birthmarks. In many cases the results are miraculous. The increase in self-esteem and happiness of many children and adolescents has been overwhelming; for some, depression has been lifted, stuttering has ceased, social involvement has increased, and antidepressants have been discontinued. There are many success stories to tell.
Despite the remarkable effects of the pulsed dye laser and the medical and psychosocial indications for its use, the issue of pain control remains significant. We have no perfect outpatient pediatric anesthetic. Most methods carry either some risk or, if not hazardous, often are not very effective for controlling pain. Needless to say, a diversity of opinions exist on how to manage discomfort from this treatment modality. Therefore, we thought it would be useful to share the experiences and opinions of several dermatologists who have extensive experience with the pulsed dye laser. 相似文献
Despite the remarkable effects of the pulsed dye laser and the medical and psychosocial indications for its use, the issue of pain control remains significant. We have no perfect outpatient pediatric anesthetic. Most methods carry either some risk or, if not hazardous, often are not very effective for controlling pain. Needless to say, a diversity of opinions exist on how to manage discomfort from this treatment modality. Therefore, we thought it would be useful to share the experiences and opinions of several dermatologists who have extensive experience with the pulsed dye laser. 相似文献
66.
Bilateral striopallidodentate calcinosis: cerebrospinal fluid, imaging, and electrophysiological studies. 总被引:3,自引:0,他引:3
B V Manyam M H Bhatt W D Moore A B Devleschoward D R Anderson D B Calne 《Annals of neurology》1992,31(4):379-384
We report the genetic, clinical, electrophysiological, and imaging studies in a family with bilateral striopallidodentate calcinosis (Fahr's disease). The intracerebral calcium deposits occurred before onset of the symptoms in the third decade of life. Progressive neurological deterioration occurred in the fifth decade of life in the proband. Cerebrospinal fluid homocarnosine, a central nervous system-specific peptide, was increased twofold in patients with autosomal dominant bilateral stripallidodentate calcinosis; in sporadic cases, there was no detectable homocarnosine and a decreased level of histidine. With advancing age, the amount of calcification increases, but it has not been determined if a critical amount must be reached before symptoms occur. Computerized tomography is superior to magnetic resonance imaging for radiological diagnosis. Despite diffuse striatal calcification, striatal 6-[18F]fluoro-L-dopa uptake did not reveal any difference between patients and control subjects, from which we infer persisting integrity of the nigrostriatal dopaminergic pathway. 相似文献
67.
D A Frambach C E Roy J L Valentine S F Boles J J Weiter C L Schepens 《Ophthalmic surgery》1988,19(2):98-100
The prevalence of cardiovascular disease (by EKG criteria) in patients with rhegmatogenous retinal detachments has been reported to be more than four times that found in age-matched controls. Adhesion between the retinal pigment epithelium (RPE) and the photoreceptors is facilitated by RPE transport. Because RPE transport is driven by a Na-K ATPase, it has been suggested that the correlation of EKG abnormalities and retinal detachment may be due to clinical use of digoxin, a Na-K ATPase inhibitor frequently given to patients with cardiovascular disease. The prevalence of EKG abnormalities in 299 consecutive patients with primary retinal detachment is about the same as that reported previously. However, 92% of these patients with EKG abnormalities did not take digoxin. Therefore, clinical use of digoxin cannot account for the reported association of EKG abnormalities and rhegmatogenous retinal detachment. 相似文献
68.
Summary Ultrastructural and tracer studies have demonstrated that vasogenic edema, a serious complication of brain tumor is the result of increased permeability of tumor vessels. However, not much information is available on the alterations in the vessels in the peritumoral areas. Therefore, we studied the ultrastructural changes in the tumor micro-blood vessels (MBVs) in 20 cases of glioma and compared these with the changes in the peritumoral MBVs in 10 of these cases.The tumor MBVs showed remarkable structural changes, viz, increase in pinocytotic vesicles, large vacuoles and microvilli in the endothelial cells, varying degrees of endothelial attenuation and fenestration, an occasional partially or completely opened-up junction and some pale and edematous endothelial cells, which can adequately explain their increased permeability.The peritumoral MBVs also showed evidence of increased permeability in the form of increased pinocytotic vesicles, large vacuoles and microvilli associated with pale and edematous cytoplasm of some endothelial cells. Thickened multilayered basement membrane, absence of ensheathment of capillary basement membrane by astrocytic cell processes and widened perivascular space were observed in both tumoral and peritumoral MBVs.An interesting observation was that in the peritumoral MBVs, the pinocytotic vesicles were most conspicuously seen on the abluminal side of the endothelial cells often fused with the abluminal plasma membrane. Although a static study like this cannot indicate any definite direction of movement of fluid, we feel that the occurrence of reverse pinocytosis is a distinct possibility in the peritumoral MBVs and that it may be an important means of resorption of edema fluid. 相似文献
69.
Cameron Platell John Mackay Brian Collopy Roy Fink Peter Ryan Rodney Woods 《ANZ journal of surgery》1995,65(8):570-575
This study reviewed a series of patients with Crohn's disease managed by surgeons of the Department of Colon and Rectal Surgery, St Vincent's Hospital, Melbourne, since 1978. There were 306 patients: 171 males and 135 females. The mean age at diagnosis was 33.4 years (range 11–93). The distribution of the disease was small bowel 32.3%, small bowel and colon 26.5%, colon 39.9%, and anal disease alone 1.6%. A total of 416 abdominal operations were performed on 204 patients. The commonest indications for surgery were failed medical therapy (21.9%), small bowel obstruction (15.9%), enteric tistula (10.1%), and intra-abdominal abscess (10.1%). The most frequently performed procedures were ileocolic resection with anastomosis (28.8%), small bowel resection (9.4%), and total colectomy and ileostomy (7.0%). Postoperative complications included anastomotic leaks in 4.0%. intra-abdominal abscess formation in 3.6%, and enterocutaneous fistulae developed in 6%. Three patients died during the review period. During follow up (mean 84.4). 30% of patients developed recurrence requiring further surgery at a mean of 72.7 months postoperatively. The most frequent site for a recurrence was the pre-anastomotic terminal ileum (61.7%). In conclusion. the majority of patients with Crohn's disease will require resectional surgery at some stage. This can be performed with a low mortality and morbidity, and a recurrence rate of around 5% per year. 相似文献
70.