全文获取类型
收费全文 | 2969篇 |
免费 | 167篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 125篇 |
妇产科学 | 112篇 |
基础医学 | 220篇 |
口腔科学 | 59篇 |
临床医学 | 379篇 |
内科学 | 712篇 |
皮肤病学 | 47篇 |
神经病学 | 108篇 |
特种医学 | 159篇 |
外科学 | 301篇 |
综合类 | 192篇 |
一般理论 | 1篇 |
预防医学 | 383篇 |
眼科学 | 18篇 |
药学 | 191篇 |
1篇 | |
中国医学 | 74篇 |
肿瘤学 | 50篇 |
出版年
2016年 | 26篇 |
2015年 | 53篇 |
2014年 | 68篇 |
2013年 | 69篇 |
2012年 | 106篇 |
2011年 | 112篇 |
2010年 | 97篇 |
2009年 | 64篇 |
2008年 | 100篇 |
2007年 | 98篇 |
2006年 | 119篇 |
2005年 | 107篇 |
2004年 | 64篇 |
2003年 | 58篇 |
2002年 | 53篇 |
2001年 | 44篇 |
2000年 | 38篇 |
1999年 | 63篇 |
1998年 | 51篇 |
1997年 | 59篇 |
1996年 | 52篇 |
1995年 | 50篇 |
1994年 | 62篇 |
1993年 | 38篇 |
1992年 | 53篇 |
1991年 | 53篇 |
1990年 | 46篇 |
1989年 | 59篇 |
1988年 | 50篇 |
1987年 | 61篇 |
1986年 | 65篇 |
1985年 | 45篇 |
1984年 | 34篇 |
1983年 | 25篇 |
1981年 | 31篇 |
1980年 | 32篇 |
1979年 | 26篇 |
1977年 | 25篇 |
1976年 | 29篇 |
1972年 | 31篇 |
1971年 | 27篇 |
1969年 | 29篇 |
1967年 | 24篇 |
1966年 | 25篇 |
1959年 | 39篇 |
1958年 | 58篇 |
1957年 | 88篇 |
1956年 | 45篇 |
1955年 | 77篇 |
1954年 | 67篇 |
排序方式: 共有3149条查询结果,搜索用时 15 毫秒
21.
22.
Policosanol is a new cholesterol-lowering drug isolated and purified from sugar-cane wax. which prevents the development of lipofundin-induced lesions and foam-cell formation in New Zealand rabbits and Wistar rats. This study was conducted to examine the effects of policosanol on foam-cell formation in carrageenan-induced granulomas in rats. Eighteen Wistar rats were randomly distributed in three experimental groups which received orally for 20 days Tween 20 H2O as vehicle (control group) or policosanol at 2.5 or 25 mg kg?1. At the 11th day. lipofundin was injected intrapcritoneally for 8 days to induce formation of foam cells in the granuloma. At day 13, carrageenan was injected subcutaneously for granuloma induction and seven days later animals were killed. A significant reduction of the foam-cell formation in granulomas of policosanol-treated rats was observed. It is concluded that policosanol prevents the development of foam cells in carrageenan-induced granulomas (extravascular medium) in rats. 相似文献
23.
Jacob H. Conn MD 《Child psychiatry and human development》1989,20(1):3-13
The method of the play interview offers the fearful child an opportunity to express himself by speaking for a series of dolls representing siblings, parents, teachers or himself. It is not the child who is aggressive, fearful, jealous or desires the parent's affection, but the doll. In this manner, the child learns to make connections between his fears and his unacceptable bad thoughts, feelings or wishes. Improvement occurs after several play interviews.This article is dedicated to Dr. Leo Kanner (1894–1981), former Director of the Children's Psychiatric Service of the Johns Hopkins HospitalLecture given to the Division of Child Psychiatry, Department of Psychiatry and Behavioral Sciences The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, Md, 21205, on September 6, 1988. 相似文献
24.
Twelve Sardinian patients affected by histologically defined classic Kaposi's sarcoma (KS) were HLA-A, B, C and DR typed. Compared to 220 age and ethnically matched healthy controls, KS patients showed a significant increase in HLA-DR5 (66.6 vs 23.1%, P less than 0.001) and a considerable decrease in HLA-DR3 (8.3 vs 53.6%, P = 0.0055). No definite association was observed for other HLA antigens. These results confirm the existence of an HLA associated genetic control of KS susceptibility and support the hypothesis that HLA-DR5 plays the role of a predisposition marker while HLA-DR3 bears a genetic resistance to the disease. 相似文献
25.
Neuron-specific enolase. Assessment by ELISA in patients with small cell carcinoma of the lung 总被引:1,自引:0,他引:1
Measurement of tissue-specific enolase isoenzymes may be of assistance in identifying small cell carcinomas of the lung and in distinguishing them from other pulmonary tumors. Enolase (E.C. 4.2.1.11) is a dimeric enzyme composed of various permutations of three immunologically distinct subunits alpha, beta, and gamma. Five isoenzymes alpha alpha, beta beta, gamma gamma, alpha beta, and alpha gamma have been identified. Immunohistochemical studies using antibodies to the gamma subunit have localized alpha gamma and gamma gamma specifically within neuronal and neuroendocrine tissues. Because of this limited distribution, neuron-specific enolase (NSE) can function as a biochemical marker for neuroendocrine tumors. The authors developed an enzyme-linked immunosorbent assay (ELISA) using the double antibody sandwich method. The sandwich is composed of rabbit antirat enolase that cross-reacts to the human gamma monomer, making the test specific for the gamma gamma isoenzyme. The avidin-biotin-peroxidase complex system is used to provide increased assay sensitivity. Serum samples from patients with histologically diagnosed small cell carcinoma have concentration of NSE 20- to 30-fold greater than that found in normal serum. Studies were conducted on patients with a variety of malignant pulmonary lesions and compared with controls to determine the value of NSE as a tumor marker. 相似文献
26.
James J. Doherty Sudar Alagarsamy Kristopher J. Bough P. Jeffrey Conn Raymond Dingledine David D. Mott 《The Journal of physiology》2004,561(2):395-401
We investigated group II metabotropic glutamate receptor (mGluR) modulation of glutamatergic input onto hilar-border interneurones and its regulation of feedback inhibition in the dentate gyrus. Selective activation of group II mGluRs with (2 S ,2' R ,3' R )-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV) depressed mossy fibre (MF)-evoked excitatory drive to these interneurones with significantly greater depression in juvenile than adult rats. During 20 Hz MF stimulus trains, EPSCs became depressed. Depression during the early, but not later part of the train was significantly greater in juvenile than adult rats and was blocked by the mGluR antagonist (2 S )-2-amino-2-[(1 S ,2 S )-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY341495). In dentate granule cells from juvenile rats polysynaptic feedback IPSCs, but not monosynaptic IPSCs, were strongly suppressed by DCG-IV. DCG-IV also suppressed feedback inhibition of perforant path-evoked population spikes. In contrast, in adult animals DCG-IV did not significantly depress feedback inhibition. During 20 Hz stimulus trains in juvenile animals the summation of polysynaptic, but not monosynaptic IPSCs was suppressed by synaptically activated group II mGluRs. Blockade of these mGluRs with LY341495 significantly increased the area and duration of the summated IPSC, causing greater feedback inhibition of granule cell firing. In contrast, in adult animals LY341495 did not alter feedback inhibition following the stimulus train. These findings indicate that group II mGluRs modulate excitatory drive to interneurones in a developmentally regulated manner and thereby modulate feedback inhibition in the dentate gyrus. 相似文献
27.
David Bruce Conn Anthony Ricciardi Mohan N. Babapulle Kristine A. Klein David A. Rosen 《Parasitology research》1996,82(1):1-7
Dreissenid mussels, Dreissena polymorpha and D. bugensis, were found to be infected by the naidid oligochaete Chaetogaster limnaei at four sites in the St. Lawrence River. This is the first report of this species infecting dreissenids anywhere in the world. Most worms inhabited the mantle cavity, where they caused erosion of the mantle and gill epithelia as determined by histopathological examination. Others penetrated various tissues; one had invaded the ovary and was feeding on oocytes and ovarian tissues. Of 606 mussels examined, 166 (27.4%) harbored at least 1 C. limnaei. The prevalence varied between 1% and 80%, depending on the collection site and date. The worms were slightly but significantly more prevalent in D. bugensis than in D. polymorpha. The intensity ranged from 1 to 18 worms per infected host. Variations in prevalence and intensity were not related to the size or sex of the host, but the data did suggest some seasonality. 相似文献
28.
Astrid LA. Kuijpers Rolph Pfundt Patrick LJM Zeeuwen Henri OF. Molhuizen Edwin CM. Mariman Peter CM. van de Kerkhof Joost Schalkwijk 《Clinical genetics》1998,54(1):96-101
Psoriasis is a multifactorial skin disease characterised by epidermal abnormalities and infiltration by lymphocytes and polymorphonuclear leukocytes (PMN). Skin-derived antileukoproteinase (SKALP), also known as elafin, is a potent inhibitor of human leukocyte elastase and proteinase 3, two PMN-derived proteinases implicated in tissue destruction and leukocyte migration. We have shown that, at least at the protein level, SKALP is significantly decreased in lesional skin of patients with pustular psoriasis compared with plaque-type psoriasis. This finding raised the possibility that SKALP could be one of the candidate genes for pustular forms of psoriasis. We therefore performed single strand conformation polymorphism (SSCP) analysis on the SKALP gene to screen for mutations/polymorphisms in the exons of 30 patients with plaque-type psoriasis, 15 patients with pustular psoriasis and 48 healthy controls. In exon 1 a polymorphism was detected at position + 43 relative to the translation start site, resulting in a substitution of threonine for alanine in the signal peptide. In the promoter region a dinucleotide repeat polymorphism was identified. Both polymorphisms were not associated with pustular psoriasis, or psoriasis in general. Our data indicate that the decrease in SKALP activity in pustular psoriasis is not caused by mutations in the coding region of the gene, and that there is no allelic association between pustular psoriasis and SKALP gene polymorphisms. 相似文献
29.
The functional of B-L (Ia-equivalent)-positive (B-L+) adn -negative (B-L-) chicken peripheral blood lymphocytes (PBL) was studied in vitro and in vivo. The PBL were first stained in direct immunofluorescence tests with a fluorescein isothiocyanate-labelled anti-B-L alloantiserum and then separated by means of a fluorescence-activated cell sorter. In agreement with our previous findings, B-L- cells showed functional properties of T lymphocytes, responding to concanavalin A and phytohaemagglutinin-P in vitro and inducing a graft-versus-host (GVH) reaction when injected into allogeneic embryos. Sorted B-L+ gave no responses in any of these assays. Neither B-L+ nor B-L- cells, when tested alone, responded significantly to pokeweed mitogen, but mixtures of the two restored the responsiveness to that of the original unsorted suspension. Of the B-L+ PBL, 10% were T cells, which may account for the low GVH reactivity given by this population. 相似文献
30.
J. M. Rothfeld J. F. Hejtmancik P. M. Conn D. W. Pfaff 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1987,69(1):113-118
Summary The slow potential change (spc) accompanying spreading depression (SD) was studied in rats and in a seizure-sensitive strain of Mongolian gerbil under three different experimental paradigms, each involving the use of naloxone. Gerbils undergoing electroconvulsive shock treatment displayed SD during the post-ictal phase, which was blocked by the intraperitoneal (i.p.) administration of naloxone (20–50 mg kg-1). Topical application of naloxone to the exposed cortex of the anaesthetized gerbil and rat blocked the spc of SD evoked by KCl. Microiontophoretic ejection of naloxone during extracellular recordings reversed cell refractoriness following the spc, demonstrated by the observation of a maintained sensitivity to iontophoretic pulses of glutamate. The results suggest a possible involvement of naloxone-sensitive processes in the mechanism responsible for cortical SD. 相似文献