全文获取类型
收费全文 | 1340816篇 |
免费 | 100853篇 |
国内免费 | 4275篇 |
专业分类
耳鼻咽喉 | 16817篇 |
儿科学 | 43780篇 |
妇产科学 | 36494篇 |
基础医学 | 198705篇 |
口腔科学 | 35975篇 |
临床医学 | 130324篇 |
内科学 | 259143篇 |
皮肤病学 | 26456篇 |
神经病学 | 112310篇 |
特种医学 | 48436篇 |
外国民族医学 | 366篇 |
外科学 | 184739篇 |
综合类 | 28895篇 |
现状与发展 | 1篇 |
一般理论 | 470篇 |
预防医学 | 115008篇 |
眼科学 | 29120篇 |
药学 | 99239篇 |
6篇 | |
中国医学 | 3168篇 |
肿瘤学 | 76492篇 |
出版年
2021年 | 10970篇 |
2019年 | 11717篇 |
2018年 | 16413篇 |
2017年 | 12365篇 |
2016年 | 13338篇 |
2015年 | 15277篇 |
2014年 | 20917篇 |
2013年 | 32219篇 |
2012年 | 44497篇 |
2011年 | 47141篇 |
2010年 | 27234篇 |
2009年 | 25042篇 |
2008年 | 42983篇 |
2007年 | 45354篇 |
2006年 | 45445篇 |
2005年 | 43836篇 |
2004年 | 41806篇 |
2003年 | 39707篇 |
2002年 | 38496篇 |
2001年 | 60999篇 |
2000年 | 62697篇 |
1999年 | 52420篇 |
1998年 | 14651篇 |
1997年 | 13335篇 |
1996年 | 13179篇 |
1995年 | 12502篇 |
1994年 | 11681篇 |
1993年 | 10961篇 |
1992年 | 41707篇 |
1991年 | 40892篇 |
1990年 | 39569篇 |
1989年 | 37478篇 |
1988年 | 34681篇 |
1987年 | 33795篇 |
1986年 | 32262篇 |
1985年 | 30752篇 |
1984年 | 23084篇 |
1983年 | 19667篇 |
1982年 | 11795篇 |
1979年 | 20872篇 |
1978年 | 14856篇 |
1977年 | 12111篇 |
1976年 | 11934篇 |
1975年 | 12169篇 |
1974年 | 14860篇 |
1973年 | 14532篇 |
1972年 | 13407篇 |
1971年 | 12457篇 |
1970年 | 11518篇 |
1969年 | 10442篇 |
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
991.
992.
Patients with complaints of halitosis do seek treatment from physicians and dental practitioners, because of the fear that their halitosis may interfere with their social activities. Although the prevalence of halitosis has been reported to be as high as 50%, most physicians and dental practitioners are poorly informed about the causes and treatments of halitosis. In order to care for patients with complaints of halitosis a multidisciplinary team was established at the Erasmus Medical Centre, Rotterdam, The Netherlands. The team included a dental hygienist, an otorhinolaryngologist, and a dentist, who developed a special halitosis programme. One short press release regarding the establishment of the team, was provided to the national press-centre. In the out-patient clinic more than 700 patients were seen by the team. Using a structured questionnaire fed to a PC, patients answered questions regarding complaints about the oral cavity, the upper respiratory tract, the throat, their general health, their cleansing habits of the oral cavity, and prior experiences with general physicians, dental practitioners, and medical specialists. They underwent examinations of the extent of their halitosis, of the perioral and neck region, the oral cavity, the upper respiratory tract, and the upper digestive tract. Finally, the members of the team came to a joint diagnosis and a joint treatment plan for every individual patient. Of the first 700 consecutive patients around 90% had a natural dentition without removable partial dentures. More than 60% were diagnosed as having periodontal disease with pockets of 4 mm or more in the maxilla. This figure was more than 50% in the mandible. Around 95% had tongue coating. 相似文献
993.
Comparative assesment of gingival thickness using transgingival probing and ultrasonographic method.
A decided attitude of expectation among many patients has given a new perspective to regenerative and plastic periodonta surgery. With authors emphasizing on the importance of gingival thickness, attempts are being made to obtain necessary information atraumatically and rapidly. Hence in the present study an attempt has been made to compare the two methods of assessing gingival thickness i.e transgingival probing and ultrasonographic method and also assess the gingival thickness in relation to central incisor lateral incisor and canine in Indian population. The gingival thickness was assessed in patients with healthy gingiva by both the methods. It was observed that transgingival probing method significantly over estimated the thickness of gingiva than the ultrasonographic method and the thickness of gingiva varies with morphology of the crown. It was concluded that compared to transgingival probing ultrasonographic method assesses gingiva thickness more accurately, rapidly and atraumatically. 相似文献
994.
The results of treatment of 7 patients with extensive hepatic hemangiomas are analysed. In 6 patients the diagnosis was established before the operation. The liver was resected in 4 patients. One patients with malignant degeneration of the hemangioma was inoperable, in another the hemangioma was not removed because of his old age, and still in another because the process had spread. The authors conclude that in large hemangiomas of the liver in young and middle-aged patients resection of the organ is indicated, especially if there is a destruction cavity and a rapid growth of hemangioma. The operation is not indicated in capillary, surface hemangiomas of a small size, old age of the patient, extension of the process in to the main vascular structures of the other hepatic lobe. 相似文献
995.
We previously showed that a low frequency (1 Hz) train of perforant path stimulation evokes burst discharges in the dentate gyrus of hippocampal slices obtained from patients surgically treated for intractable temporal lobe epilepsy. We report here that multiple population spikes that characterize the burst discharge are blocked reversibly by the specific NMDA receptor antagonist, D-(-)-2-amino-5-phosphonovaleric acid (D-APV). The epileptiform discharge evoked in human dentate gyrus by stimulation trains of 1 Hz could be reproduced in the rat dentate gyrus in vitro by the same stimulation protocol but required the presence of low concentrations (0.2-0.6 mM) of extracellular magnesium. We suggest that low frequency orthodromic stimulation of dentate granule cells through the perforant path progressively evokes an increase in the activation of NMDA receptors resulting in burst discharges in tissue from epileptic patients. 相似文献
996.
CEEG mapping in drug-free schizophrenics. Differences from healthy subjects and changes induced by haloperidol treatment. 总被引:1,自引:0,他引:1
A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment. 相似文献
997.
The glomerular layer of the olfactory bulb contains a substantial population of dopaminergic neurons. We determined the quantity and location of D1 and D2 dopamine receptors which are the presumed targets of these neurons. Binding of the D1 selective ligand [3H]SCH23390 was slightly above background and was distributed through all layers of the bulb except the olfactory nerve layer. In contrast there were relatively high levels of [3H]spiperone binding to D2 DA receptors in the glomerular and olfactory nerve layers. The presence of relatively high concentrations of D2 DA receptors in both the nerve layer and glomerular layer suggests the novel hypothesis that these receptors may be localized on terminals of the olfactory nerve. 相似文献
998.
G C Palmer M L Stagnitto J M Ordy R C Griffith J J Napier R J Gentile J H Woodhead H S White E A Swinyard 《Epilepsy research》1991,8(1):36-48
Stereoisomers of remacemide (racemate form) were compared for anticonvulsant efficacy and safety in mice. In the maximal electroshock seizure (MES) test for oral efficacy, the (-) stereoisomer, FPL 14145, was more potent than the racemate or the (+) stereoisomer, FPL 14144. Respective ED50 values (expressed as mg/kg) were: remacemide, 58; FPL 14145, 45; FPL 14144, 79. In 2 of 3 tests for neural impairment, FPL 14145 yielded significantly better therapeutic indices (toxic dose 50/ED50) than the racemate. The margin of safety (estimated median lethal dose ED50) was more favorable for FPL 14144: remacemide, 15.1; FPL 14144, 18.9; FPL 14145, 15.7. The duration of protection against MES indicated the stereoisomers were longer acting than the racemate. After intravenous administration the order of potency against MES was similar: FPL 14145 greater than remacemide greater than FPL 14144. Following daily administration of the oral ED98 for 4 days, with a dose response curve run on day 5, the MES ED50 values for all compounds were increased. The test indicates tolerance. In the pentylenetetrazol infusion test the racemate and FPL 14144 demonstrated more proconvulsant properties than FPL 14145. Intraperitoneal administration of 50 mg/kg or more produced changes in behavior with all compounds. At higher doses the racemate and FPL 14145 elicited more severe symptoms with death at 200 mg/kg. 相似文献
999.
Long-term cognitive deficits in patients after surgery on aneurysms of the anterior communicating artery. 总被引:4,自引:2,他引:2 下载免费PDF全文
L M Stenhouse R G Knight B E Longmore S N Bishara 《Journal of neurology, neurosurgery, and psychiatry》1991,54(10):909-914
The long term recovery of a series of 27 patients who had undergone rupture and repair of an aneurysm of the anterior communicating artery was assessed using a number of neuropsychological measures. Testing took place 12 to 84 months post surgery. On the basis of the results from tests of intellect, memory, and conceptual learning, three subgroups of patients were identified: those with persuasive cognitive defects, those with evidence of residual frontal lobe damage and those who showed no evidence of dysfunction. The occurrence of cerebral vasospasm was the most consistent predictor of long term cognitive deficit. 相似文献
1000.
BACKGROUND. A health risk appraisal (HRA) is a tool for health promotion. Conversational microcomputer-based HRAs may be more cost effective than other HRA formats. The acceptability of conversational HRAs, however, has not been demonstrated for older adults. METHODS. We studied the acceptability of a conversational microcomputer-based HRA in a sample of 247 adults at the Minnesota State Fair and the Senior Options Exposition. All users were offered the appraisal via mouse or keyboard interface. Acceptability was measured in terms of user-reported helpfulness, intent to change, time of use, and willingness to view HRA health recommendations. Data on completion time and willingness to view HRA recommendations were collected for Senior Exposition users only. Regression analyses were used to examine the combined impact of interface (mouse or keyboard), location (State Fair or Senior Exposition), age, and sex on user acceptability. Results. Interface and location had no effect on helpfulness or change ratings. Older users rated the appraisal more helpful (P less than .007). Both older and female users reported more intent to change behavior (P = .016, both). Time to use the appraisal was related to interface, age, and sex. Mouse users (P less than .0001), older users (P less than .0001) and female users (P less than .05) took significantly longer to use the appraisal. Significantly more mouse users declined to see recommendations (P less than .02). CONCLUSIONS. Older users can derive as much or more value from conversational health risk appraisals as younger users; however, a mouse interface may be less effective for this age group. 相似文献