全文获取类型
收费全文 | 3406824篇 |
免费 | 277015篇 |
国内免费 | 13826篇 |
专业分类
耳鼻咽喉 | 46172篇 |
儿科学 | 101669篇 |
妇产科学 | 84380篇 |
基础医学 | 540767篇 |
口腔科学 | 92196篇 |
临床医学 | 306665篇 |
内科学 | 599846篇 |
皮肤病学 | 89345篇 |
神经病学 | 292308篇 |
特种医学 | 132791篇 |
外国民族医学 | 117篇 |
外科学 | 535402篇 |
综合类 | 99408篇 |
现状与发展 | 23篇 |
一般理论 | 2424篇 |
预防医学 | 281216篇 |
眼科学 | 78523篇 |
药学 | 237024篇 |
27篇 | |
中国医学 | 9860篇 |
肿瘤学 | 167502篇 |
出版年
2021年 | 56276篇 |
2020年 | 35834篇 |
2019年 | 59244篇 |
2018年 | 72562篇 |
2017年 | 55257篇 |
2016年 | 60933篇 |
2015年 | 75209篇 |
2014年 | 110000篇 |
2013年 | 175805篇 |
2012年 | 98251篇 |
2011年 | 98247篇 |
2010年 | 118989篇 |
2009年 | 122862篇 |
2008年 | 84829篇 |
2007年 | 87809篇 |
2006年 | 98749篇 |
2005年 | 93907篇 |
2004年 | 95173篇 |
2003年 | 85620篇 |
2002年 | 75001篇 |
2001年 | 104297篇 |
2000年 | 97114篇 |
1999年 | 97151篇 |
1998年 | 65358篇 |
1997年 | 63123篇 |
1996年 | 60769篇 |
1995年 | 56164篇 |
1994年 | 50154篇 |
1993年 | 46890篇 |
1992年 | 67494篇 |
1991年 | 63709篇 |
1990年 | 60181篇 |
1989年 | 59746篇 |
1988年 | 55129篇 |
1987年 | 53895篇 |
1986年 | 50768篇 |
1985年 | 51171篇 |
1984年 | 46730篇 |
1983年 | 42998篇 |
1982年 | 40985篇 |
1981年 | 38627篇 |
1980年 | 36306篇 |
1979年 | 37457篇 |
1978年 | 33505篇 |
1977年 | 31170篇 |
1976年 | 27973篇 |
1975年 | 26512篇 |
1974年 | 26972篇 |
1973年 | 25631篇 |
1972年 | 24097篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The aqueous, organic, and volatile oil extracts of leaves of Eugenia uniflora Linn. Family Myrtaceae were investigated for antibacterial properties using agar dilution techniques. The aqueous extract was the most active against the organisms compared to the organic and volatile oil extracts. The extracts were found to inhibit Gram positive Staphylococcus aureus and Bacillus subtilis and Gram negative Escherichia coli and Shigella dysentcriae. Pseudomonas aeruginosa, Klebsiella pneumoniac, and Salmonella typhi were not inhibited. 相似文献
992.
Summary Split or full thickness eyelid defects resulting from tumor destruction or surgical excision present a dilemma for plastic and reconstructive surgeons. Full thickness eyelid replacement requires composite grafting of the skin, together with tarsal support of its substitute and mucosa. The flap described by Fricke in 1829 was used for reconstruction of anterior lamella in six lower eyelid defects. In three of our cases chondromucosal grafts taken from nasal septum were utilized for posterior lamella repair. The results have been satisfactory from a functional and cosmetic standpoint. 相似文献
993.
994.
ABSTRACT. A 54-year-old profoundly mentally retarded female patient with phenylketonuria and a severe behaviour problem was treated with a restricted protein and high energy diet. After several weeks of dietary intervention the patient's behaviour improved significantly. 相似文献
995.
Uptake of iodine-123 MIBG by pheochromocytomas, paragangliomas, and neuroblastomas: a histopathological comparison 总被引:2,自引:0,他引:2
J Bomanji D A Levison W D Flatman T Horne P M Bouloux G Ross K E Britton G M Besser 《Journal of nuclear medicine》1987,28(6):973-978
The percentage uptake of [123I]metaiodobenzylguanidine (MIBG) by tumors of the paraganglion system is compared with the number of neurosecretory granules (assessed by both light and electron microscopy) in the subsequently resected tumors in six patients. Iodine-123 MIBG was injected intravenously; the tumor uptake of [123I]MIBG varied between 0.001% and 0.14% of the injected dose per gram of tumor tissue at 22 hr. The number of neurosecretory granules in tissue sections was scored on a scale of I-III. A direct proportional correlation was found between the percentage uptake of [123I]MIBG by the tumor and the number of neurosecretory granules in the tissue sections but not with plasma or urinary catecholamines. This technique for imaging reflects the storage status of the tumor better than plasma and urinary catecholamine measurements. 相似文献
996.
Endogenous opioids are present in neurons of the vagus and the intrinsic nervous system and they are colocalized with gastrin in antral G-cells. This raises the possibility that endogenous opioids modulate gastrin release. Stimulation of both cervical vagi (10V, 5Hz, 5ms) elicited an increase of arterial plasma gastrin levels at intragastric pH7 or pH2. The response at pH2 was 30% of that at luminal pH7. Atropine reduced vagally stimulated gastrin levels substantially. At luminal pH2 the small residual noncholinergic response was mediated neither by adrenergic mechanisms nor by endogenous opioids. At luminal pH 7 adrenergic blockade with phentolamine and propranolol reduced vagally stimulated gastrin by 60%. In the presence of atropine adrenergic blockade elicited only a small inhibitory effect suggesting that vagal activation of adrenergic mechanisms depends on atropine-sensitive cholinergic pathways. Blockade of opiate receptors by naloxone had no effect on vagal gastrin release, however, the noncholinergic gastrin response was reduced significantly by naloxone, suggesting that cholinergic mechanisms normally restrain activation of endogenous opioids during vagal stimulation. Naloxone had no effect on the noncholinergic, nonadrenergic stimulation of gastrin levels. These data suggest that endogenous opioids can contribute to vagal gastrin release provided the cholinergic restraint is blocked and adrenergic mechanisms stimulate endogenous opioids. In conclusion a major role of endogenous opioids in the regulation of vagal gastrin release can not be detected. 相似文献
997.
Up to now two abnormal nephrographic patterns have been described as a result of arterial hypotension as an adverse response to urographic contrast material. We would like to describe a third pattern. 相似文献
998.
(E)-5-(2-Bromovinyl)-2'-deoxyuridine (1; BrVUdR) inhibits the replication of herpes simplex virus type 1 (HSV-1) and of varicella-zoster virus (VZV) in vitro at concentrations of 0.01 to 0.23 mumol/l, whereas herpes simplex virus type 2 (HSV-2) is influenced only at 5.5 to 27 mumol/l. In comparison to some classical and newly developed antiherpetics, i. e. 5-iodo-2'-desoxyuridine (2; idoxuridine, IDU), 9-beta-D-arabinofuranosyladenine (4; vidarabine Ara-A), 9-(2-hydroxyethoxymethyl) guanine (5; acyclovir, ACV) and 2'-fluoro-5-iodo-1-beta-D-aracytosine (6;FIAC) the following order of decreasing activity was found:1 greater than 6 greater than 5 greater than 2 greater than 4 (against HSV-1) and 6 greater than 2 greater than 5 greater than 1 greater than 4 (against HSV-2). The high selectivity of the antiviral effect of BrVUdR towards HSV-1 and TZV is based on the fact, that proliferation of different mammalian cell lines is inhibited by 50% only at concentrations as high as 90 to 170 mumol/l, resulting in a therapeutical index of 1000 to 10,000. Successful treatment of an HSV-1 encephalitis in mice as well as an HSV-1 keratitis of rabbits confirmed the efficiency of 1 in experimental animal infections. No toxic side effects in both local and systemic applications were observed. Promising data from cell culture and animal experiments recommend 1 as a potential candidate for the local and systemic treatment of HSV-1 and VZV infections in man. 相似文献
999.
1000.
A HIGH FREQUENCY OF INHERITED DEFICIENCY OF COMPLEMENT COMPONENT C4 IN DARWIN ABORIGINES 总被引:2,自引:0,他引:2
Abstract A high frequency of serum complement component C4A deficiency may explain the higher prevalence and greater severity of systemic lupus erythematosus reported in Australian Aborigines. Inherited deficiencies of serum complement components C4A, C4B, and C2 were examined in two Australian Aboriginal populations from Darwin and Alice Springs and compared with the prevalence of complement deficiencies in white Australian blood donors. The frequency of C4A deficiency alleles was 29% in Darwin Aborigines compared with 12% in Alice Springs and 17% in Canberra blood donors. Partial C4B deficiency was also higher in Darwin Aborigines than in the other populations. Inherited deficiency of serum complement component C2 was not observed. 相似文献