全文获取类型
收费全文 | 514487篇 |
免费 | 33375篇 |
国内免费 | 617篇 |
专业分类
耳鼻咽喉 | 6894篇 |
儿科学 | 16848篇 |
妇产科学 | 13528篇 |
基础医学 | 85051篇 |
口腔科学 | 14474篇 |
临床医学 | 44411篇 |
内科学 | 93731篇 |
皮肤病学 | 12162篇 |
神经病学 | 36230篇 |
特种医学 | 18467篇 |
外国民族医学 | 63篇 |
外科学 | 77148篇 |
综合类 | 8471篇 |
一般理论 | 118篇 |
预防医学 | 39017篇 |
眼科学 | 12135篇 |
药学 | 40571篇 |
中国医学 | 1006篇 |
肿瘤学 | 28154篇 |
出版年
2018年 | 4951篇 |
2015年 | 4521篇 |
2014年 | 6078篇 |
2013年 | 9571篇 |
2012年 | 12905篇 |
2011年 | 14301篇 |
2010年 | 8323篇 |
2009年 | 7786篇 |
2008年 | 13723篇 |
2007年 | 14721篇 |
2006年 | 14966篇 |
2005年 | 14388篇 |
2004年 | 14072篇 |
2003年 | 13407篇 |
2002年 | 13292篇 |
2001年 | 24083篇 |
2000年 | 25090篇 |
1999年 | 20565篇 |
1998年 | 5435篇 |
1997年 | 4708篇 |
1996年 | 5042篇 |
1995年 | 4626篇 |
1994年 | 4319篇 |
1993年 | 4136篇 |
1992年 | 15731篇 |
1991年 | 16321篇 |
1990年 | 16424篇 |
1989年 | 15803篇 |
1988年 | 14580篇 |
1987年 | 14422篇 |
1986年 | 13599篇 |
1985年 | 12979篇 |
1984年 | 9628篇 |
1983年 | 8250篇 |
1982年 | 4563篇 |
1981年 | 4232篇 |
1979年 | 9418篇 |
1978年 | 6857篇 |
1977年 | 5773篇 |
1976年 | 5602篇 |
1975年 | 6397篇 |
1974年 | 7634篇 |
1973年 | 7130篇 |
1972年 | 6961篇 |
1971年 | 6685篇 |
1970年 | 6172篇 |
1969年 | 5888篇 |
1968年 | 5559篇 |
1967年 | 5012篇 |
1966年 | 4450篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
Of 66 patients (31 female and 35 male) with demyelinating inflammatory polyradiculoneuropathy (DIP), 12% (8/66) had a chronic relapsing and/or progressive course (CR-DIP) and 88% (58/66) had an acute monophasic illness (acute Guillain-Barré syndrome or GBS). Ten (15%) of the 66 had one or more associated putative autoimmune diseases; of these ten, five had CR-DIP and five had GBS. Cell-mediated immune responsiveness (CMI) of 30 cases with DIP was tested in vitro by lymphocyte transformation. Peripheral nervous system neuritogenic protein (NP) and central nervous system encephalitogenic myelin basic protein were the challenge antigens. Eighteen (60%) of the 30 patients had CMI to NP of human peripheral nervous system origin when a stimulation index (SI) of 2 or more was evaluated as positive; eight 27% (1) had CMI to NP when a positive SI was 3 or more. Of the 44 control patients with other neuropathies, only two (4.6%) demonstrated CMI to NP (SI, greater than or equal to 2). The in vitro response of patients with DIP to myelin basic protein (7/30) was not significantly different from that of the control population (16/44). The high incidence of DIP associated with autoimmune diseases and the CMI to NP in this group suggest that DIP may be an autoimmune disease with NP as one possible major antigen. 相似文献
922.
Menhaden fish oil, n-3 polyunsaturated fatty acids, and protection of newborn rats from oxygen toxicity 总被引:2,自引:0,他引:2
We have previously reported that newborn rats born to mothers fed a high n-6 polyunsaturated fatty acid (PUFA) (safflower oil) diet demonstrated increased n-6 PUFA in lung lipids and superior tolerance to high oxygen exposure. In the present study, we explored whether high n-3 PUFA might also protect against hyperoxic damage and by what mechanism. Adult female rats were fed either regular rat chow, a high n-3 (menhaden fish oil-based) diet, or a high n-6 (safflower oil-based) diet for 6 wk before and then throughout pregnancy and lactation. Newborn offspring of the high n-3 (fish oil) dams demonstrated increased n-3 PUFA (i.e. eicosapentaenoic and docosahexaenoic acid) and decreased n-6 PUFA (i.e. linoleic and arachidonic acid) in their lung lipids compared to the other two diet groups. The high n-6 (safflower oil) offspring had the opposite PUFA lung lipid pattern (with increases in total n-6 fatty acids and decreases in total n-3 fatty acids). The high n-3 offspring demonstrated markedly decreased lung levels of prostaglandin E2, F2 alpha and thromboxane B2, whereas the high n-6 offspring had higher eicosanoid levels than the regular diet offspring. Offspring of both high n-6 and high n-3 diet dams demonstrated essentially the same superior hyperoxic tolerance compared to regular diet offspring [7-d (greater than 95% O2) survival rates of 110/115 and 99/109, respectively, versus 70/91, p less than 0.01].(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
923.
Treatment of symptomatic hyponatremia and its relation to brain damage. A prospective study 总被引:10,自引:0,他引:10
We studied the effects of replacement therapy in two groups of patients with symptomatic hyponatremia. Thirty-three patients, who were studied prospectively, had no evidence of cerebral demyelinating lesions. Their hyponatremia (mean serum sodium concentration [+/- SE], 108 +/- 1 mmol per liter) was increased to 126 +/- 1 mmol per liter with hypertonic saline (856 mM) delivered at a rate of 1.3 +/- 0.2 mmol per liter per hour. The serum sodium concentration did not rise to normal or hypernatremic levels in the first 48 hours of therapy, and none of these patients had a respiratory arrest or other hypoxic episode. Twelve patients, evaluated retrospectively, had evidence of cerebral demyelinating lesions at autopsy or on computerized axial tomography. The rate of correction of hyponatremia (1 +/- 0.2 mmol per liter per hour) was similar to the rate in the patients in Group I. However, at least one of four characteristics was present: an increase in serum sodium to normal or hypernatremic levels in the first 48 hours, a change in the serum sodium concentration of more than 25 mmol per liter in the first 48 hours, a hypoxic-anoxic episode, and an elevation of serum sodium to hypernatremic levels in patients with hepatic encephalopathy. Although these four features were associated with demyelination, our observations suggest that this complication does not depend on the rate of correction of hyponatremia. 相似文献
924.
A. I. Fabra De Peretti G. B. Mori De Moro N. E. Ghittoni A. M. Evangelista De Duffard R. O. Duffard 《Environmental toxicology》1987,2(2):217-228
The effects of 2,4-Dichlorophenoxyacetic acid on the growth rate, chemical composition, 14C-2,4-dichlorophenoxyacetic acid and 45Ca2+ uptake by Rhizobium sp. M 4 able to nodulate Arachis hypogaea were determined. Cellular growth was diminished by the presence of 10?3 M 2,4-dichlorophenoxyacetic acid in the medium. Alterations in cellular chemical composition, in 14C-2,4-dichlorophenoxyacetic acid and in 45Ca2+ uptake were found. 相似文献
925.
Summary The histogenesis of stromal cells in capillary hemangioblastoma has been the subject of debate. The light and electron microscopic studies of hemangioblastomas presented here showed pericytic and leiomyoblastic features in stromal cells. Cells cultured by the monolayer method showed similar features to those of the original tumors. Immunohistochemical studies for glial fibrillary acidic protein and factor VIII/von Willebrand factor indicated that stromal cells were antigenically distinct from astrocytes and endothelial cells. These findings suggest that stromal cells are closely related to pericytes and smooth muscle cells, and support Rhodin's speculation that pericytes serve as a precursor to smooth muscle cells. 相似文献
926.
927.
The authors presented some data on the platelet deforming ability in patients with acute and chronic renal failure treated with hemodialysis. Platelet deformity was studied by means of a proposed method of the filtration of platelet suspension through glass filtering funnels with a porous plate (GOST 9775-69). The deterioration of platelet deformity in patients with uremia and its direct correlation with a degree of nitremia were established. It was assumed that the deterioration of platelet deformity resulted in premature cell destruction and anemia development. Platelet deformity can be used as a test to characterize platelet function in patients with renal failure. The problem of the appropriateness of trental therapy was discussed. 相似文献
928.
929.
I Enander A K Ulfgren H Nygren R Holmdahl L Klareskog P Larsson S Ahlstedt 《International archives of allergy and applied immunology》1987,82(3-4):361-363
Epicutaneous sensitization with picrylchloride (PiCl) induced a strongly delayed hypersensitivity (DH) reaction in mice. Local challenge in the airways of these mice resulted in increased numbers of mononuclear cells, mast cells and mucus cells. Depletion of T helper cells in vivo by treatment with monoclonal antibody (GK 1.5) inhibited the DH reaction. This treatment also resulted in a decrease in the number of mononuclear and mucus cells in the lung after intranasal challenge. The DH reaction was transferred to recipients with immune lymph node cells and spleen cells from mice sensitized epicutaneously with PiCl. The recipient mice also showed a slight increase in the number of mononuclear cells in the lung after intranasal challenge. These results indicate that T cells are not only involved in the DH reaction but also in the accompanying lung reaction. 相似文献
930.
M Fukuoka T Tanimoto Y Zhou N Kawasaki A Tanaka I Ikemoto T Machida 《Journal of applied toxicology : JAT》1989,9(4):277-283
Repeated oral doses of di-n-butyl phthalate (DBP) to male rats caused a decrease in testicular fructose and glucose and a sloughing of the germ cells on the first day of treatment. On day 2, more severe sloughing was seen and was accompanied by decreases in testicular iron and zinc levels and increases in the level of inositol and cholesterols. The sloughing was followed by atrophy, accompanied by dissociation of the germ cells from the Sertoli cells and reduction of triglycerides, cholesterols and phospholipids containing choline and ethanolamine residues in the testis. 相似文献