全文获取类型
收费全文 | 862694篇 |
免费 | 70490篇 |
国内免费 | 1839篇 |
专业分类
耳鼻咽喉 | 12802篇 |
儿科学 | 24633篇 |
妇产科学 | 25109篇 |
基础医学 | 124270篇 |
口腔科学 | 25494篇 |
临床医学 | 75367篇 |
内科学 | 164673篇 |
皮肤病学 | 16980篇 |
神经病学 | 70100篇 |
特种医学 | 35245篇 |
外国民族医学 | 171篇 |
外科学 | 136244篇 |
综合类 | 24607篇 |
现状与发展 | 2篇 |
一般理论 | 263篇 |
预防医学 | 66888篇 |
眼科学 | 20522篇 |
药学 | 64735篇 |
中国医学 | 1593篇 |
肿瘤学 | 45325篇 |
出版年
2018年 | 7337篇 |
2015年 | 7733篇 |
2014年 | 11118篇 |
2013年 | 16802篇 |
2012年 | 22752篇 |
2011年 | 23851篇 |
2010年 | 13888篇 |
2009年 | 13079篇 |
2008年 | 22592篇 |
2007年 | 24643篇 |
2006年 | 24525篇 |
2005年 | 24167篇 |
2004年 | 23723篇 |
2003年 | 22860篇 |
2002年 | 21949篇 |
2001年 | 35833篇 |
2000年 | 36484篇 |
1999年 | 30911篇 |
1998年 | 9225篇 |
1997年 | 8550篇 |
1996年 | 8478篇 |
1995年 | 8011篇 |
1994年 | 7726篇 |
1992年 | 26661篇 |
1991年 | 26104篇 |
1990年 | 25627篇 |
1989年 | 24684篇 |
1988年 | 23222篇 |
1987年 | 22888篇 |
1986年 | 21749篇 |
1985年 | 21102篇 |
1984年 | 16396篇 |
1983年 | 14001篇 |
1982年 | 8855篇 |
1981年 | 8204篇 |
1980年 | 7673篇 |
1979年 | 16746篇 |
1978年 | 12117篇 |
1977年 | 10184篇 |
1976年 | 9331篇 |
1975年 | 10156篇 |
1974年 | 12652篇 |
1973年 | 12145篇 |
1972年 | 11539篇 |
1971年 | 10686篇 |
1970年 | 10220篇 |
1969年 | 9913篇 |
1968年 | 8901篇 |
1967年 | 8231篇 |
1966年 | 7657篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Twenty-four-hour intragastric acidity and clinical trial of bedtime enprostil 70 μg compared with ranitidine 300 mg in duodenal ulcer 总被引:2,自引:2,他引:0
R. P. WALT R. E. POUNDER C. J. HAWKEY I. A. SANTANA K. W. SOMERVILLE R. F. A. LOGAN R. G. LONG M. J. S. LANGMAN 《Alimentary pharmacology & therapeutics》1987,1(2):161-166
The effects of bedtime 70 micrograms and twice daily 35 micrograms doses of enprostil on 24-hour intragastric acidity were investigated in nine duodenal ulcer patients in remission. Median nocturnal acidity decreased significantly by 30% with 35 micrograms twice daily, and by 48% with 70 micrograms at bedtime. In a clinical trial using bedtime dosing, 102 duodenal ulcer patients randomly received either ranitidine 300 mg or enprostil 70 micrograms. More ulcers healed after 4 and 8 weeks treatment with ranitidine than with enprostil (76% ranitidine vs 52% enprostil, at 4 weeks p = 0.0065 and 94% vs 68%, respectively at 8 weeks, P = 0.0007). However, 6 months after cessation of treatment there was no material difference in overall outcome. Despite combining mucosal protection with acid inhibition enprostil treatment conferred no advantage over simple acid inhibition. 相似文献
962.
963.
Epidemiology of multiple sclerosis in the north-east (Grampian region) of Scotland--an update. 总被引:10,自引:3,他引:7 下载免费PDF全文
The north-east of Scotland (Grampian Region) has undergone three incidence and prevalence surveys, including the present one, since 1970. Results from these indicate a true increase in the prevalence of the disease in the region. The incidence of the disease has remained continuously high and shows a slightly upward trend. Literature on the subject of repeated surveys in different regions of the world has been reviewed in detail. The need for a prevalence study from the south of the British Isles has been emphasised in order to enable one to judge if the increase in Scotland is in keeping with the pattern in the whole of the British Isles. The familial incidence of the disease was noted to be virtually unchanged between the three surveys. Certain other aspects of aetiological significance have been analysed, viz, clustering of patients at birth or at onset of the disease; ages of occurrence of childhood viral infections such as measles, mumps, chickenpox and rubella; and the role of canine distemper infection. 相似文献
964.
P. Habermeyer E. Kaiser K. Wolf W. Stock 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1986,369(1):766-767
Zusammenfassung Der distal gestielte Peronaeus-Insellappen, erstmals 1984 von Yoshimura publiziert, ist ein fasciocutaner Lappen, der über einen Hautast der A. peronea ernährt wird. Die A. peronea weist distal, ca 5 cm oberhalb des Sprunggelenkes, einen Ramus perforans zur A. tibialis anterior auf und über einen Ramus communicans besteht eine Verbindung zur A. tibialis posterior. Unterbindet man die A. peronea proximal der Abgangsstele der Hautarterie, so kommt es über die distalen Anastomosen zur retrograden Durchblutung. Der distal gestielte Peronaeuslappen besitzt einen großen Schwenkbereich bis hin zum Fußrücken. Die Durchgängigkeit der drei Unterschenkelarterien ist die Voraussetzung für die Durchführbarkeit. Die Indikation ergibt sich bei oberflächlichen Knochen- und Hautdefekten im distalen Unterschenkeldrittel, der Malleolengabel, der Ferse und des Fußrückens. 相似文献
965.
966.
967.
Toxocariasis: a serological survey of blood donors in the Australian Capital Territory together with observations on the risks of infection 总被引:4,自引:0,他引:4
W L Nicholas A C Stewart J C Walker 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1986,80(2):217-221
The sera from 660 healthy blood donors from Canberra were tested for antibodies to Toxocara canis by the ELISA test. The results were compared with those from patients with suspected or confirmed visceral larva migrans or ocular toxocariasis. Over 7% of Canberra sera showed elevated levels of antibody reacting with T. canis antigen. Sera from patients resident in Australia with other helminth parasites did not cross-react with T. canis antigen in our tests. However, studies of sera collected in several tropical countries with other parasitic infection, show that cross-reactions with other parasites are possible. The use of purified glycoprotein antigen does not alter the possibility of cross-reaction. Observations and experiments show that people in Canberra may be exposed to the infective eggs of T. canis. 相似文献
968.
W A Turski M Dziki E Urbanska L S Calderazzo-Filho E A Cavalheiro 《Synapse (New York, N.Y.)》1991,7(3):173-180
Systemic (s.c.) administration of aminooxyacetic acid (AOAA) in mice triggered clonic convulsions with a CD50 (convulsive dose) of 68 mg/kg (range 54-86). AOAA also induced clonic convulsions in mice subjected to intracerebroventricular administration of the drug with a CD50 of 0.04 mumols (range 0.028-0.06). At the onset of convulsions induced by systemic AOAA (CD97;150 mg/kg), the GAD activity in the frontal cortex and hippocampus was not affected. GABA mimetic drugs, progabide and gabaculine, had no effect on convulsions induced by AOAA. Convulsions induced by systemic administration of AOAA were blocked by diazepam, phenobarbital, and valproate. Ethosuximide, trimethadione, acetazolamide, diphenylhydantoin, and carbamazepine remained ineffective. L-Phenylisopropyladenosine was also found to protect mice against AOAA-induced convulsions, whereas atropine and baclofen had no effect. The seizures induced by intracerebroventricular administration of AOAA (CD97; 0.1 mumols) were blocked by coadministration of preferential N-methyl-D-aspartate antagonists, D-(-)-2-aminophosphonoheptanoic (AP7), 3-[+/-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonic (CPP), and kynurenic acid (KYNA); preferential quisqualate/kainate antagonists, 6-cyano-7-nitro-quinoxaline-2,3-dione and gamma-D-glutamylaminomethylsulphonic acid, remained inactive in the range of dosages sufficient to block seizures induced by quisqualic acid or kainic acid. The antagonistic action of antiepileptic drugs effective against seizures induced by excitatory amino acids (diazepam and valproate), and drugs acting on excitatory amino acid receptors (AP7, CPP, and KYNA) upon seizures induced by AOAA suggests an involvement of excitatory neurotransmission in the convulsant action of the drug. 相似文献
969.
Lymphoscintigraphy in lymphedema: an aid to microsurgery 总被引:3,自引:0,他引:3
M Vaqueiro P Gloviczki J Fisher L H Hollier A Schirger H W Wahner 《Journal of nuclear medicine》1986,27(7):1125-1130
The role of lymphoscintigraphy, performed with 99mTc-labeled antimony sulfur colloid, in the diagnosis of lymphedema and as a test for selection of patients for microvascular operation was evaluated in 32 patients with primary and secondary lymphedema and four patients with other causes of leg edema. Lymphoscintigraphy clearly demonstrated if edema was of lymphatic origin. Five different image patterns were identified; abnormal image patterns could not be predicted from clinical history or physical findings. Quantitative evaluation of removal of the radioactive colloid from the injection site and appearance in lymph node sites and liver was of limited usefulness. Nine patients underwent various surgical procedures before or after lymphoscintigraphy. Lympho-venous anastomoses were possible only in patients who had patent lymph channels visible on lymphoscintigrams. Based on initial experience, lymphoscintigraphy seems to be useful to select patients for microvascular operation. 相似文献
970.
Allografts of CNS tissue possess a blood-brain barrier. II. Angiogenesis in solid tissue and cell suspension grafts 总被引:2,自引:0,他引:2
R D Broadwell H M Charlton P S Ebert W F Hickey Y Shirazi J Villegas A L Wolf 《Experimental neurology》1991,112(1):1-28
Angiogenesis and patency of blood vessels were analyzed qualitatively in solid CNS and peripheral tissue syngeneic, allogeneic, and xenogeneic grafts and in individual cell suspension grafts of astrocytes, fibroblasts, PC12, and three additional tumor cell lines placed intracerebrally in adult host mice. Postgrafting survival times were 1 day through 4 weeks. The patency of graft vessels was determined in sections from immersion-fixed tissues incubated to reveal the endogenous peroxidase activity of host red cells trapped within the lumen of blood vessels. Additionally, horseradish peroxidase (HRP) was administered intravenously to live hosts; HRP labels host brain and graft vessels on the luminal surface and reveals the presence or absence of a blood-brain barrier (BBB) within the grafts. The origins of blood vessels supplying solid tissue xenografts were identified immunohistochemically with primary antibodies against host (athymic AKR mice) and donor (fetal Lewis rats) major histocompatibility complex (MHC) class I. Blood vessels supplying solid CNS grafts at 1-7 days post-transplantation were identified ultrastructurally and possessed interendothelial tight junctional complexes; however, they were not perfused with either host blood or blood-borne HRP prior to 8 days. Graft vessels at 10 days were outlined consistently by peroxidase-positive red cells in immersion-fixed material and labeled with blood-borne HRP. These vessels provided a BBB to the circulating HRP and exhibited interendothelial tight junctions. Evidence of angiogenesis within solid anterior pituitary grafts and the variety of cell suspension grafts was obtained prior to 3 days post-transplantation in immersion-fixed preparations; the vessels, with the notable exception of those supplying astrocyte cell suspensions, failed to present a BBB to blood-borne peroxidase. Endothelia in the solid pituitary allografts and the PC12 cell grafts were highly fenestrated and exhibited open interendothelial junctions; those in the tumor and fibroblast cell grafts, for the most part, appeared nonfenestrated, and many possessed open interendothelial junctional complexes. Immunostaining for host and donor MHC class I revealed that donor blood vessels predominate over host vessels in CNS xenografts and supply pituitary xenografts exclusively; in both preparations, donor vessels were not identified within the host CNS. Because cell suspension grafts were derived from endothelia-free preparations grown in culture, blood vessels supplying these grafts were necessarily of host CNS origin and manifested a morphological transformation from a BBB to a non-BBB endothelium. The data suggest that angiogenesis in solid CNS grafts placed into the adult host CNS, compared to similarly placed solid peripheral tissue/cell suspension grafts, is not rapid.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献