全文获取类型
收费全文 | 36745篇 |
免费 | 3753篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 477篇 |
儿科学 | 1044篇 |
妇产科学 | 749篇 |
基础医学 | 5260篇 |
口腔科学 | 1371篇 |
临床医学 | 4208篇 |
内科学 | 7349篇 |
皮肤病学 | 419篇 |
神经病学 | 2951篇 |
特种医学 | 1334篇 |
外国民族医学 | 2篇 |
外科学 | 4810篇 |
综合类 | 928篇 |
一般理论 | 30篇 |
预防医学 | 3850篇 |
眼科学 | 1005篇 |
药学 | 2812篇 |
1篇 | |
中国医学 | 28篇 |
肿瘤学 | 1918篇 |
出版年
2021年 | 522篇 |
2020年 | 329篇 |
2019年 | 556篇 |
2018年 | 606篇 |
2017年 | 452篇 |
2016年 | 476篇 |
2015年 | 588篇 |
2014年 | 813篇 |
2013年 | 1225篇 |
2012年 | 1673篇 |
2011年 | 1765篇 |
2010年 | 963篇 |
2009年 | 932篇 |
2008年 | 1553篇 |
2007年 | 1646篇 |
2006年 | 1514篇 |
2005年 | 1584篇 |
2004年 | 1436篇 |
2003年 | 1379篇 |
2002年 | 1359篇 |
2001年 | 1098篇 |
2000年 | 1153篇 |
1999年 | 1073篇 |
1998年 | 399篇 |
1997年 | 339篇 |
1996年 | 380篇 |
1995年 | 357篇 |
1994年 | 349篇 |
1993年 | 362篇 |
1992年 | 858篇 |
1991年 | 842篇 |
1990年 | 875篇 |
1989年 | 785篇 |
1988年 | 744篇 |
1987年 | 740篇 |
1986年 | 700篇 |
1985年 | 714篇 |
1984年 | 527篇 |
1983年 | 486篇 |
1982年 | 306篇 |
1981年 | 327篇 |
1980年 | 290篇 |
1979年 | 471篇 |
1978年 | 381篇 |
1977年 | 308篇 |
1976年 | 293篇 |
1974年 | 374篇 |
1973年 | 361篇 |
1972年 | 297篇 |
1971年 | 311篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Cardiomyopathy: a late complication of hemolytic uremic syndrome 总被引:2,自引:0,他引:2
Amanda M. Walker Lee N. Benson Greg J. Wilson Gerald S. Arbus 《Pediatric nephrology (Berlin, Germany)》1997,11(2):221-222
This report describes a child who presented with classic hemolytic uremic syndrome (HUS) and 4 months later developed a life-threatening
but reversible cardiomyopathy with global cardiac dysfunction and a left ventricular ejection fraction of 14%. There was no
evidence of electrolyte abnormalities, anemia, hypertension, severe fluid overload, or viral infection. Endomyocardial biopsies
were consistent with a dilated cardiomyopathy. This paper highlights the importance of considering the diagnosis of associated
cardiomyopathy when presenting with late-onset edema following HUS.
Received February 12, 1996; received in revised form and accepted August 22, 1996 相似文献
72.
Maria-Carmen Wilson Jack . Greenberg Steven Barrer C. P. Shah 《Journal of neuroimaging》1992,2(3):156-158
Spinal cord infarction or ischemia predominates in the thoracic region, less so in the cervical and lumbar regions. Different etiological factors have been implicated in anterior spinal artery syndrome. Magnetic resonance imaging (MRI) allows in vivo imaging of spinal cord disease, including infarction. A 31-yearold, previously healthy man had an acute onset of interscapular pain, followed by rapid development of quadriparesis associated with paresthesias and mild bladder dysfunction. Initial MRI of the cervicothoracic region demonstrated normal findings. A repeat study obtained 6 days later showed marked increase in the cervical cord size, especially at the C6-7 level. On the T2-weighted sagittal series and after gadolinium injection, increased signal in the anterior portions of the cord extending from C-4 to the T2-3 interspace was noted. This was most prominent at the C-6 and C-7 levels. The coronal views revealed abnormal high signal in the region of the anterior horns of the gray matter, a finding that is recognized as an “owl's eyes” pattern. Because the MRI changes of cerebral infarction may succeed a clinical event by hours or days, accurate diagnosis may require delayed or repeated studies. This report suggests that the diagnosis of spinal cord disease requires a similar evaluation. 相似文献
73.
Subcutaneous melatonin implants were administered to castrated hand-reared male red deer (Cervus elaphus) during a 63 d period in spring, after which effects on voluntary feed intake (VFI), rumen pool size, rumen capacity (i.e. volume) and heart rate were measured on four occasions, evenly spread over a 12-month period, with the deer individually fed indoors on a diet of lucerne (Medicago sativa) chaff. Blood samples for hormone determinations were taken at intervals throughout the study. Day-time plasma melatonin concentration was approximately 5 pg/ml in control animals, whereas during melatonin administration it increased to 60-150 pg/ml and declined to 30 pg/ml by 142 d after the last implantation. Melatonin administration markedly depressed plasma prolactin concentration during the period of implantation, but thereafter plasma prolactin concentration rose in the treated animals during autumn and winter, whilst it declined in control animals over this period. VFI, rumen pool size and heart rate in control animals attained highest values in summer and lowest values in winter, showing a pronounced seasonal cycle. Melatonin administration depressed all these values in late spring and summer and increased all the values in autumn and winter, relative to control animals, and appeared to move the cycles by approximately 6 months. Melatonin-treated animals showed maximum values for all these measurements during winter. The castrated male deer showed little seasonal change in live weight, which was not affected by melatonin administration. The findings support the view that melatonin probably mediates the effect of daylength on digestive function in red deer. Rumen capacity remained relatively constant throughout the year, but rumen pool size as a proportion of rumen capacity increased with increasing VFI. 相似文献
74.
Survival from colorectal cancer has not improved over the last four decades despite advances in surgery and anaesthesia. The answer to the question whether adjuvant chemotherapy and radiotherapy will improve survival from the disease can only come from randomised, controlled trails. In the future, immunotherapy and gene therapy may be of benefit but these are still many years from the clinical arena. We believe that current evidence suggests that patients with Dukes B and C colorectal cancer should be entered into trials of adjuvant therapy. This evidence is reviewed below among with estimates of the impact that adjuvant therapy would have on the outcome from this disease in Northern Ireland. 相似文献
75.
Ectoparasites infesting a population of urban gray squirrels (Sciurus carolinensis Gmelin) in northern Florida were collected monthly during 1974. Eleven species were identified: one flea (Orchopeas howardi (Baker], three suckling lice (Enderleinellus longiceps Kellogg & Ferris, Hoplopleura sciuricola Ferris, and Neohaematopinus sciuri Jancke), one tick (Dermacentor variabilis Say), two mesostigmatid (gamasid) mites (Androlaelaps casalis (Berlese) and A. fahrenholzi (Berlese], and four chiggers (Eutrombicula alfreddugesi (Oudemans), E. splendens (Ewing), Leptotrombidium peromysci Vercammen-Grandjean & Langston, and Parasecia gurneyi (Ewing]. The flea and three suckling lice represent core species of ectoparasites for the gray squirrel; the remainder are probably satellite species. Only E. longiceps varied significantly in prevalence or intensity of infestation among host age groups; subadult squirrels had higher intensities than adults. Peak prevalence of O. howardi occurred in January and attained maximum intensity in March, whereas both prevalance and intensity were minimum in August. Prevalence of H. sciuricola was maximum in November and remained at similar levels through June. It then declined significantly to its minimum in September-October. Intensity of infestation, however, was greatest in August, September, and January. Maximum prevalence of N. sciuri occurred from January to March and was minimum in September; intensity of infestation reached maxima in January, June, and August. 相似文献
76.
Cytoprotection by iloprost against paracetamol-induced toxicity in hamster isolated hepatocytes. 总被引:1,自引:0,他引:1
P. Nasseri-Sina D. J. Fawthrop J. Wilson A. R. Boobis D. S. Davies 《British journal of pharmacology》1992,105(2):417-423
1 The ability of iloprost (ZK36374) to protect hamster isolated hepatocytes from the toxic effects of paracetamol and its reactive metabolite N-acetyl-p-benzoquinoneimine (NABQI) was investigated. The cytoprotection provided by iloprost was compared with that of N-acetyl-L-cysteine. 2 Treatment of hepatocytes with either NABQI (0.4 mM) or paracetamol (2 mM) alone resulted in a considerable loss of cell viability, as assessed by trypan blue exclusion or leakage of lactate dehydrogenase, accompanied by an increase in the percentage of viable cells that were blebbed. N-acetyl-L-cysteine (1.25 mM) pretreatment diminished the loss of cell viability and the percentage of blebbed cells resulting from exposure to NABQI or paracetamol, whereas iloprost (10(-16) M to 10(-10) M) pretreatment reduced only the loss of cell viability, not the percentage of viable cells exhibiting blebbing. Pretreatment with N-acetyl-L-cysteine significantly attenuated the depletion by paracetamol of glutathione and decreased the covalent binding of [14C]-paracetamol to cellular proteins, whereas iloprost was without any such effects. 3 The effects of iloprost and N-acetyl-L-cysteine were also investigated by use of a model of paracetamol toxicity in which it is possible to study the biochemical events leading to cell injury separate from the generation of toxic metabolites. Hamster hepatocytes were incubated with paracetamol (4 mM) for 90 min at 37 degrees C during which metabolism of paracetamol occurs with minimal loss of cell viability.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
77.
The bedside assessment of dysphagia may be difficult, due to the inability to witness the act of swallowing directly. The milk test described in this paper gives a good assessment of swallowing, is cheap and easily portable and allows an instant decision to be made without recourse to special investigations. 相似文献
78.
T G Wilson M J Hollands J M Little 《The Australian and New Zealand journal of surgery》1992,62(2):111-115
The treatment of chronic pancreatitis commonly yields disappointing results. Patients with chronic pancreatitis and a dilated pancreatic duct can be treated by longitudinal pancreaticojejunostomy. In order to evaluate the procedure, 20 patients undergoing pancreaticojejunostomy were followed for a median time of more than 5 years. Their clinical characteristics and outcomes have been compared with a group of 43 patients with chronic pancreatitis and small pancreatic ducts. There were no differences between the two groups in the major epidemiological parameters, except that calcification in the gland was more frequently noted in those with large ducts. The operation of longitudinal pancreaticojejunostomy could be accomplished with an acceptable morbidity. There was one death in the postoperative period. Seventy-six per cent of patients were found to have benefited clinically at five years, compared with 48% of those with small duct disease. This difference was statistically significant. Patients who benefited were defined by four factors; they were carrying out their usual occupation at the time of surgery, they were not narcotic dependent at the time of surgery, they had a pancreatic duct width greater than 7 mm and, they had totally abstained from alcohol from before the operation to the time of follow-up. Longitudinal pancreaticojejunostomy probably remains the best surgical treatment for suitable patients with chronic pancreatitis. The operation should only be performed when the pancreatic duct is greater than 7 mm in width. In such patients the operation produces considerable improvement of pain with minimal metabolic disturbance. 相似文献
79.
80.
Elevated levels of acute phase plasma proteins in major depression. 总被引:10,自引:0,他引:10
P R Joyce C R Hawes R T Mulder J D Sellman D A Wilson D R Boswell 《Neuropsychopharmacology》1992,32(11):1035-1041
Levels of acute phase and other plasma proteins were measured in 21 men with major depression, 28 men with alcohol dependence, and 12 men who acted as controls. The depressed men had significantly elevated levels of the acute phase proteins, haptoglobin and alpha-1-antichymotrypsin, and of immunoglobulin G. The elevations in haptoglobin and alpha-1-antichymotrypsin were highly correlated with each other, and were correlated with the severity of depression and negatively correlated with the thyroid stimulating hormone response to thyrotropin. The alcoholic men had elevated haptoglobin levels, but significantly decreased levels of immunoglobulin G. These findings provide further evidence for an inflammatory response during depression. 相似文献