全文获取类型
收费全文 | 934634篇 |
免费 | 64487篇 |
国内免费 | 2415篇 |
专业分类
耳鼻咽喉 | 12776篇 |
儿科学 | 29721篇 |
妇产科学 | 26867篇 |
基础医学 | 132121篇 |
口腔科学 | 25071篇 |
临床医学 | 78114篇 |
内科学 | 191407篇 |
皮肤病学 | 19737篇 |
神经病学 | 74594篇 |
特种医学 | 37520篇 |
外国民族医学 | 363篇 |
外科学 | 146324篇 |
综合类 | 19131篇 |
一般理论 | 251篇 |
预防医学 | 67180篇 |
眼科学 | 20615篇 |
药学 | 66231篇 |
中国医学 | 1868篇 |
肿瘤学 | 51645篇 |
出版年
2018年 | 10073篇 |
2017年 | 7882篇 |
2016年 | 8382篇 |
2015年 | 9604篇 |
2014年 | 13329篇 |
2013年 | 20641篇 |
2012年 | 28162篇 |
2011年 | 29723篇 |
2010年 | 17823篇 |
2009年 | 16781篇 |
2008年 | 28377篇 |
2007年 | 30010篇 |
2006年 | 30026篇 |
2005年 | 29652篇 |
2004年 | 28432篇 |
2003年 | 27404篇 |
2002年 | 26935篇 |
2001年 | 42129篇 |
2000年 | 43360篇 |
1999年 | 36939篇 |
1998年 | 10178篇 |
1997年 | 9305篇 |
1996年 | 9229篇 |
1995年 | 8577篇 |
1994年 | 8204篇 |
1993年 | 7693篇 |
1992年 | 28554篇 |
1991年 | 27323篇 |
1990年 | 26735篇 |
1989年 | 25655篇 |
1988年 | 23823篇 |
1987年 | 23430篇 |
1986年 | 22521篇 |
1985年 | 21398篇 |
1984年 | 15979篇 |
1983年 | 13633篇 |
1982年 | 8178篇 |
1979年 | 14721篇 |
1978年 | 10283篇 |
1977年 | 8710篇 |
1976年 | 8222篇 |
1975年 | 9029篇 |
1974年 | 10802篇 |
1973年 | 10272篇 |
1972年 | 9750篇 |
1971年 | 9018篇 |
1970年 | 8679篇 |
1969年 | 8128篇 |
1968年 | 7777篇 |
1967年 | 7167篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
K Y Mumcuoglu J Miller R Gofin B Adler F Ben-Ishai R Almog D Kafka S Klaus 《Public health reviews》1990,18(4):335-344
BACKGROUND: The aim was to determine the influence of the socioeconomic status of the family and the hygienic practices in the home on the prevalence of head lice infestation in children. METHODS: The study was carried out by analyzing the answers to a standardized epidemiological questionnaire given to parents of school children aged 4-17 in Bet Shemesh, a medium-sized urban town 25 km from Jerusalem. RESULTS: Of 3,000 questionnaires distributed, 958 (31.9%) were completed and returned. The majority of the children (72.4%) had been previously infested with lice. Half of them had other family members, mainly brothers and sisters, who had been infested in the past with lice. In 97.5% of the families the mother was responsible for examining the children for lice, and for carrying out treatment when infestation was present. An association was found between presence of lice infestation and mother's education, age of child, and frequency of shampooing, combing, and examination for lice. There was no association between infestation rates and mother's country of origin, crowding in the home, and the sharing of combs, brushes, hats, scarves, towels, and clothes. CONCLUSIONS: There is evidence that the incidence of lice infestation depends on the hygienic practices in the home rather than on the socioeconomic status of the family or sharing of personal articles among family members. 相似文献
92.
T Abumiya I Sayama K Asakura H Hadeishi M Mizuno A Suzuki N Yasui F Shishido K Uemura 《No shinkei geka. Neurological surgery》1990,18(9):837-844
Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used. 相似文献
93.
W. F. S. Sellers 《Anaesthesia》1996,51(5):513-513
94.
Our study was intended to determine whether power Doppler sonography can be considered superior to color Doppler technique in depiction of normal orbital vasculature. Ten healthy volunteers (20 eyes) were examined with a 10 MHz linear probe; each orbital vessel was recorded with both color and power Doppler methods; the images were reviewed independently by all the observers, who agreed that power Doppler clearly is superior to color Doppler technique for evaluation of the anatomy of orbital arteries and veins. 相似文献
95.
96.
A E van der Merwe F J Mattheyse M Bedford P D van Helden D J Rossouw 《Burns : journal of the International Society for Burn Injuries》1990,16(3):193-197
Cultured keratinocytes were used as allografts on burn wounds in two patients. In both patients successful covering of the wounds was obtained. DNA fingerprinting of the epidermis covering the wounds 21 days later showed that the cultured keratinocytes were replaced by the patients' cells. 相似文献
97.
J Combe P Poinsard J Besancenot G Camelot F Cattin J F Bonneville T Moulin J L Henlin J L Chopard L Cotte 《Annals of vascular surgery》1990,4(6):558-562
Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident. 相似文献
98.
99.
LUCAS D.; MENEZ J. F.; BODENEZ P.; BACCINO E.; BARDOU L. G.; FLOCH H. H. 《Alcohol and alcoholism (Oxford, Oxfordshire)》1988,23(1):23-31
Acetaldehyde, the first metabolite of ethanol, reacts with haemoglobinin vitro to produce acetaldehydehaemoglobin adducts.Some clinical studies on the minor haemoglobins have suggestedthat these adducts may be formed in people abusing alcohol.Under hydrolysis of haemoglobin, with oxalic acid at 100°Cin sealed vials, some acetaldehyde was released and then specificallydetermined by HPLC. The kinetics of hydrolysis were studiedusing haemoglobin previously labelled with 14[C] acetaldehyde.The maximum liberation of 14[C] acetaldehyde was obtained after3 hr 30 min hydrolysis and this time factor was then utilizedin the analysis of alcoholic and control haemoglobin. Thus,we have confirmed the formation of acetaldehyde haemoglobinadducts in vivo. It must be noted that the released acetaldehydecorresponds only to an index of the stable adducts. The levelswere higher in alcoholics than in controls (1.417±0.171and 1.295±0.139 nmol/mg Hb, respectively, P<0.001).In conclusion, this marker is not a convenient tool for themonitoring of alcohol exposure levels because of the low differencesbetween alcoholic and control haemoglobins. 相似文献
100.
F M Barker 《Journal of the American Optometric Association》1988,59(7):558-560
Since its introduction in early 1985, the Volk +90D lens has become a very popular auxiliary lens for biomicroscopic fundus evaluation. The Volk +90D lens provides a wide field of view which is accessible by simple scanning of the biomicroscope. The necessity to hand hold the lens, however, has not always provided enough stability, particularly for the novice user. This article describes a newly introduced holder for the Volk +90D lens which mounts on the base of the biomicroscope headrest providing rapid and stable lens placement. Use of this holder improves the technique of retinal examination and photography by stabilizing the image and by freeing both hands to operate the slit lamp biomicroscope. The enhanced stability afforded by this holder also gives the examiner the practical capability of viewing the posterior pole without mydriasis. 相似文献