全文获取类型
收费全文 | 1684356篇 |
免费 | 115959篇 |
国内免费 | 2415篇 |
专业分类
耳鼻咽喉 | 23528篇 |
儿科学 | 55772篇 |
妇产科学 | 47821篇 |
基础医学 | 256706篇 |
口腔科学 | 45476篇 |
临床医学 | 146080篇 |
内科学 | 323802篇 |
皮肤病学 | 36090篇 |
神经病学 | 126082篇 |
特种医学 | 65425篇 |
外国民族医学 | 410篇 |
外科学 | 257639篇 |
综合类 | 32891篇 |
现状与发展 | 2篇 |
一般理论 | 399篇 |
预防医学 | 123665篇 |
眼科学 | 38984篇 |
药学 | 128795篇 |
2篇 | |
中国医学 | 3358篇 |
肿瘤学 | 89803篇 |
出版年
2018年 | 16254篇 |
2016年 | 13862篇 |
2015年 | 15821篇 |
2014年 | 21643篇 |
2013年 | 32720篇 |
2012年 | 45905篇 |
2011年 | 49654篇 |
2010年 | 29122篇 |
2009年 | 27023篇 |
2008年 | 47285篇 |
2007年 | 51491篇 |
2006年 | 51775篇 |
2005年 | 50437篇 |
2004年 | 48767篇 |
2003年 | 47389篇 |
2002年 | 46401篇 |
2001年 | 74482篇 |
2000年 | 76440篇 |
1999年 | 64591篇 |
1998年 | 18253篇 |
1997年 | 16082篇 |
1996年 | 16365篇 |
1995年 | 15414篇 |
1994年 | 14488篇 |
1993年 | 13553篇 |
1992年 | 51590篇 |
1991年 | 51976篇 |
1990年 | 51552篇 |
1989年 | 50224篇 |
1988年 | 46747篇 |
1987年 | 45940篇 |
1986年 | 43580篇 |
1985年 | 41656篇 |
1984年 | 31049篇 |
1983年 | 26875篇 |
1982年 | 15562篇 |
1981年 | 13867篇 |
1979年 | 29583篇 |
1978年 | 20833篇 |
1977年 | 17778篇 |
1976年 | 17237篇 |
1975年 | 19353篇 |
1974年 | 22590篇 |
1973年 | 21774篇 |
1972年 | 20555篇 |
1971年 | 19298篇 |
1970年 | 18020篇 |
1969年 | 17148篇 |
1968年 | 16165篇 |
1967年 | 14334篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
A. V. Dolzhenko-Podchezertseva V. V. Novikova L. M. Korkodinova T. F. Odegova 《Pharmaceutical Chemistry Journal》2005,39(1):15-17
Nineteen N-acyl-5-bromanthranilic acid amides were synthesized via acylation of 5-bromanthranilamide with suitable anhydrides. The antimicrobial activity of the synthesized compounds with respect to Staphylococcus aureus and Escherichia coli was evaluated. Compounds with diphenyl, furoyl, and tetrachlorophthalyl moieties in the acyl part of the molecule showed significant inhibition of microbial growth. The minimum inhibiting concentrations of this compounds were 15.6 μg/ml against S. aureus and 15.6 – 31 μg/ml against E. coli. Other tested amides were considerably less active.__________Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 1, pp. 17 – 18, January, 2005. 相似文献
942.
成人型多囊肾病的基因诊断—APKD基因与α珠蛋白... 总被引:7,自引:1,他引:6
Genomic DNA PvuII fragments containing the 3'HVR from 52 unrelated Chinese of Han nationality varied between 1.7 kb and 10.0 kb and showed high polymorphism. The genomic DNA PvuII fragments from five families with adult polycystic kidney disease (APKD) were analyzed using the alpha-globin gene 3' HVR (hypervariable region) as probe. The results showed a close linkage between 3'HVR and the APKD gene and segregation according to Mendelian laws. The maximum Lod score for linkage between 3' HVR and APKD was 3.372 at a recombination fraction theta = 0.01. The alpha-globin gene 3'HVR probe can therefore be used for presymptomatic gene diagnosis and prenatal diagnosis in the Han ethnic group. 相似文献
943.
Dose-response curves of angiotensin I (AI, 1.0-1000.0 pmol) and angiotensin II (AII, 1.25-1250.00 pmol) were obtained in isolated rat hearts subjected to control conditions, mild hypoxia (PO2 = 145 mm Hg), reoxygenation, ischemic (perfusion pressure = 35 mm Hg) and reperfusion. Both AI and AII caused dose-dependent coronary flow (CF) of 26 +/- 3 and 27 +/- 2%, respectively. The effects of both AI and AII were substantially attenuated during hypoxia, but were fully restored upon reoxygenation. During ischemia, the effect of AII was unaltered while the effect of AI was enhanced compared to the control (P less than 0.05). This enhancement was reversible on reperfusion. Cardiac conversion of AI, calculated from ED50 values for AI and AII, was significantly increased during ischemia (P less than 0.05). Infusion of saralasin (0.5-5.0 micrograms/min) did not increase CF in any of the groups. We conclude that (1) the coronary vasoconstrictive effect of AII is preserved in ischemia but attenuated in hypoxia and (2) cardiac conversion of AI to AII is enhanced in hearts injured by ischemia. 相似文献
944.
S W Rogers T E Hughes M Hollmann G P Gasic E S Deneris S Heinemann 《The Journal of neuroscience》1991,11(9):2713-2724
The cloning of cDNAs that encode functional glutamate receptors makes it possible to produce antibodies that can be used as high-affinity probes for the localization and characterization of these receptors in the mammalian brain. We have made antibodies to different regions of the first cloned member of this family, GluR1, using bacterially overproduced antigen. On Western blots, these antisera detect glycoprotein(s) of 105 kDa present in crude membranes of the hippocampus and cerebellum. The 105-kDa band is associated with postsynaptic densities, and it is observed in cultured cells upon transfection with the GluR1 cDNA. Although glutamate receptors are thought to be the most prevalent excitatory ligand-gated ion channel in the mammalian brain, immunohistochemistry reveals that the receptors recognized by these antisera are localized predominantly in neurons of the cerebellum and some structures of the limbic system, including the hippocampus, the central nucleus of the amygdala, and portions of the septum. This pattern of expression is, in general, consistent with the distribution of GluR1 mRNA as determined by in situ hybridization histochemistry. Our results suggest that glutamate excitatory circuits recognized by these antisera are predominantly found in regions of the limbic system that are reciprocally interconnected. 相似文献
945.
G R Bond 《New directions for mental health services》1991,(52):65-80
The author reviews recent research findings examining variations in an assertive outreach model. Mental health system and client characteristics that have influenced program implementation are discussed. 相似文献
946.
A V Levy E Laska J D Brodie N D Volkow A P Wolf 《Journal of cerebral blood flow and metabolism》1991,11(2):A103-A113
We introduce the concept of the metabolic centroid spectrum as the feature space to characterize the distribution of metabolic activity in three-dimensional brains. The method computes the metabolic centroid of a brain subvolume for each increment of metabolic activity occurring in the whole brain. The result is the metabolic spectral signature, a continuous three-dimensional curve whose shape reflects the distribution of metabolic rates in the brain. The method's sensitivity to metabolic distribution asymmetries is greatly increased over that of the metabolic centroid method, while retaining its advantages; it is almost invariant to head size, head positioning, photon scatter, and the positron emission tomography (PET) camera's full width at half-maximum. It does not require magnetic resonance, computed tomography, or x-ray images. To test the method we analyzed the metabolic PET images of 40 normal subjects and 20 schizophrenics. The results show a unification of several metabolic characteristics of schizophrenic brains, such as laterality, hypofrontality, cortical/subcortical abnormalities, and overall brain hypometabolism, which were identified by different laboratories in separate studies using differing methodologies. Here they are presented by a single automatic objective method. 相似文献
947.
D Guidetti F Gemignani S Terenziani P Ragni G Fornaciari D Dall'Asta A Marbini 《Acta neurologica Belgica》1991,91(1):12-19
Three patients with hypereosinophilia showed different forms of peripheral neuropathy: severe polyneuropathy of prevalently sensory type (case 1), mild sensory neuropathy (case 2), acute mononeuropathy of the median nerve with subclinical polyneuropathy (case 3). Hypereosinophilia was probably idiopathic, however the presence of atypical findings suggested transition to vasculitides or collagen disease. Sural nerve biopsy in cases 1 and 2 showed features of axonopathy in both, although of different severity, reflecting the variability of clinical involvement and, probably, heterogeneous pathogenic mechanisms. Peripheral nerve involvement associated with hypereosinophilia may be related to neurotoxicity of eosinophils, or to vascular damage. 相似文献
948.
Critical illness polyneuromyopathy after artificial respiration. 总被引:3,自引:0,他引:3
A A Op de Coul G A Verheul A C Leyten R L Schellens J L Teepen 《Clinical neurology and neurosurgery》1991,93(1):27-33
Up to now, 71 critically ill patients have been reported with neuromuscular complications after artificial respiration. The authors review the literature and present data of a personal series of 22 patients all suffering from severe flaccid tetraparesis and muscle atrophy, which developed after an average of two weeks artificial respiration. The prognosis was relatively good in those surviving the primary disease. The multiconditional causes are discussed with emphasis on the combination of polyneuropathy and myopathy. Tumor necrosis factor (TNF), a key mediator of sepsis, which also has an influence on muscle and nerves, is mentioned as a possible cause of this illness. 相似文献
949.
R. N. KALARIA ‡‡ P. G. GALLOWAY† G. PERRY‡ ‡‡ 《Neuropathology and applied neurobiology》1991,17(3):189-201
Amyloid P (AP) component is present in all types of systemic amyloid deposits. Recently, it has been shown to be also present in cerebral amyloid lesions of Alzheimer's disease (AD). In this study, we used immunocytochemical methods to extend these findings at the electron microscope level and characterize the spectrum of AP immunoreactivity in neurofibrillary pathology (NFP) of AD and other neurodegenerative disorders including Down's syndrome (DS), Creutzfeldt-Jakob, Parkinson's, Pick's and diffuse Lewy body diseases and progressive supranuclear palsy. In AD and DS, AP immunoreaction product was evident in all the classical amyloid lesions and NFP in a large sample of all cortical areas examined. The distribution and relative intensity of immunostaining was similar to that of thioflavin S staining in serial sections. In many cases, however, plaques and vessels stained by anti-AP serum were not apparent with thioflavin S. Serial sections immunostained with antiserum to amyloid A, C-reactive protein or to other proteins involved in systemic amyloidoses and the acute phase response showed no evidence of staining in any of the cerebral lesions. Electron microscopy confirmed that AP immunoreactivity was associated with the abnormal filaments characteristic of NFP as well as amyloid fibrils found in plaques and vessels showing congophilic amyloid angiopathy. Plaques of Creutzfeldt-Jakob disease, Pick bodies of Pick's disease, tangles and Lewy bodies in Parkinson's disease and a subpopulation of Lewy bodies in the diffuse Lewy body disease coexistent with AD were also stained. With the exception of vessels in two of the five cases, AP was not detected in age-matched controls. Our observations indicate AP to be a consistent feature of cerebral NFP and amyloid deposits. 相似文献
950.
D Mezzano G E del Pino M Montesinos M E García E Aranda A Foradori 《Thrombosis and haemostasis》1991,66(2):254-258
Thrombocytopenia was induced in mongrel dogs by two mechanisms: immunologically, by intravenous injection of heterologous antiplatelet antibody, and non-immunologically, by circulating the blood through glass beads in anesthetized animals. The platelet content of 5-HT was monitored before and during the recovery of the blood platelet counts. This period is associated with the normalization of the mean platelet survival time and with a progressive increase in the mean age of the circulating platelet population. A continuous increment in platelet 5-HT closely followed the increase in platelet counts in both models of thrombocytopenia, and a strong correlation was found between the platelet age and 5-HT content. These findings support the concept that platelets accumulate 5-HT during their physiological aging process, contradicting the notion that a negative balance in 5-HT content results at the end of their physiological lifespan in circulation. These results are not in conflict with the concept that circulating platelets release and re-uptake 5-HT. 相似文献