全文获取类型
收费全文 | 1190篇 |
免费 | 61篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 60篇 |
妇产科学 | 81篇 |
基础医学 | 111篇 |
口腔科学 | 19篇 |
临床医学 | 156篇 |
内科学 | 269篇 |
皮肤病学 | 12篇 |
神经病学 | 129篇 |
特种医学 | 135篇 |
外科学 | 118篇 |
综合类 | 20篇 |
一般理论 | 6篇 |
预防医学 | 65篇 |
眼科学 | 26篇 |
药学 | 60篇 |
中国医学 | 2篇 |
肿瘤学 | 25篇 |
出版年
2020年 | 6篇 |
2019年 | 13篇 |
2018年 | 13篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 14篇 |
2014年 | 24篇 |
2013年 | 49篇 |
2012年 | 33篇 |
2011年 | 31篇 |
2010年 | 42篇 |
2009年 | 38篇 |
2008年 | 43篇 |
2007年 | 50篇 |
2006年 | 25篇 |
2005年 | 38篇 |
2004年 | 28篇 |
2003年 | 21篇 |
2002年 | 22篇 |
2001年 | 25篇 |
2000年 | 26篇 |
1999年 | 31篇 |
1998年 | 45篇 |
1997年 | 40篇 |
1996年 | 46篇 |
1995年 | 32篇 |
1994年 | 23篇 |
1993年 | 27篇 |
1992年 | 23篇 |
1991年 | 34篇 |
1990年 | 43篇 |
1989年 | 42篇 |
1988年 | 46篇 |
1987年 | 45篇 |
1986年 | 33篇 |
1985年 | 25篇 |
1984年 | 17篇 |
1983年 | 20篇 |
1982年 | 23篇 |
1981年 | 15篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 18篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1973年 | 11篇 |
1971年 | 6篇 |
1967年 | 8篇 |
1965年 | 6篇 |
排序方式: 共有1296条查询结果,搜索用时 0 毫秒
101.
102.
103.
Spreading Cerebral Oligemia in Classical- and Normal Cerebral Blood Flow in Common Migraine 总被引:2,自引:0,他引:2
SYNOPSIS
Regional cerebral blood flow was studied with intra-arterial133 Xenon technique in 254 areas of a hemisphere during the development of classical migraine attacks in seven patients. We describe a gradual spread of reduced cerebral blood flow starting at the posterior pole of the hemisphere and advancing in a mode quite similar to the spreading depression phenomenon of Leao. In three patients the oligemia was preceeded by focal or perifocal hyperemia. Functional activation by speech etc. was usually impaired or abolished during prodromes or accompaniments. Headache was found concommitantly with cerebral blood flow reduction and cannot be caused by reactive hyperemia in these patients. Similar findings were made in two patients studied with tomographic 133 Xenon technique. During induced common migraine attacks repeated cerebral blood flow studies with stationary detectors (N =3) and with tomographic technique (N =4) revealed no alterations of global or cerebral blood flow. Also tomographic determination of spontaneous common migraine attacks in four patients was normal. It is concluded that the two forms of migraine are different with respect to cerebral blood flow abnormalities and that they should be studied separately in the future. Greater interest should be directed towards the phenomenon of spreading depression as a possible model of the classical migraine attack. 相似文献
Regional cerebral blood flow was studied with intra-arterial
104.
Kai Jensen Peer Tfelt-Hansen Martin Lauritzen Jes Olesen 《Cephalalgia : an international journal of headache》1985,5(3):125-131
In a randomized, double-blind cross-over study, 43 patients with classic migraine received 40 mg Nimodipine and placebo as sublingual capsules. There was no significant effect on patients' preference, development of headache, need for escape medicine, duration of headache, severity of headache or headache index. Considerable methodological problems were encountered. Only 54% of the 79 patients selected for the trial could be evaluated. Suggestions for future trials are made. 相似文献
105.
Group a streptococcal antigens cross-reactive with myocardium. Purification of heart-reactive antibody and isolation and characterization of the streptococcal antigen 总被引:25,自引:17,他引:25 下载免费PDF全文
Heart-reactive antibody (HRA) appears in the sera of experimental animals inoculated with group A streptococci as well as patients with acute rheumatic fever. Adsorption of either serum with group A streptococcal membranes will remove the HRA. Blocking experiments between these two types of HRAs have demonstrated that the antibodies are directed towards different antigenic determinants on either the same or different molecules. To isolate and purify the antigen from the group A streptococcus cross-reactive with sarcolemmal sheaths of cardiac myofibers, it became necessary to purify the HRA from rheumatic fever patients’ sera. Isolated gamma globulin containing all of the HRA was adsorbed onto human sarcolemmal sheaths. The specific HRA was released by using potassium iodide. Over 99 percent of the purified HRA was shown to bind the sarcolemmal sheath whereas less than 1 percent of the antibody would bind nonspecifically to other material. Preparations of group A streptococcal membrane will bind HRA purified from the sera of acute rheumatic patients at levels of 97 percent or greater. The cross-reactive antigen solubilized by nonionic detergent was purified 120-fold by column chromatography. On sodium dodecyl sulfate polyacrylamide electrophoresis, the antigen was demonstrated to be composed of four polypeptides with mol wt of 32,000, 28,000, 26,000, and 22,000 daltons, respectively. Only proteolytic enzymes could destroy the antigenic determinant whereas glycosidases and lipases had no effect. The purified antigen blocked the binding of purified HRA to normal human heart sections. 相似文献
106.
JB Robins MRCOG 《International journal of clinical practice》1995,49(3):164-165
SUMMARY A case of cord presentation associated with the presence of a complex true knot is described and the aetiology and risks reconsidered. 相似文献
107.
Prevalence of cytomegalovirus antibody in hemophiliacs and homosexuals infected with human immunodeficiency virus type 1 总被引:1,自引:0,他引:1
We determined the prevalence of antibody to cytomegalovirus (CMV) in the sera of non-homosexual hemophilia patients and homosexual men infected with the human immunodeficiency virus type 1 (HIV-1). CMV antibody testing by latex agglutination revealed 33 of 58 HIV-1 infected hemophiliacs (57%) were antibody-positive compared with 54 of 54 HIV-1 infected asymptomatic non-hemophiliac homosexuals (100%) (p less than .001). Nine of 15 hemophiliacs (60%) with symptomatic HIV-1 infection were CMV antibody-positive. We also tested 22 HIV-1 antibody-negative hemophiliacs who had received non-heat treated factor concentrates. 14 of these 22 (64%) were CMV antibody-positive compared with 57% of HIV-1 antibody-positive hemophiliacs. We conclude 1) there is little correlation between transmission of HIV-1 and CMV by factor concentrates, 2) the presence of CMV antibody does not appear to be associated with clinical stage of HIV-1 infection in hemophiliacs, and 3) there may be a significant number of CMV antibody-negative hemophiliacs with HIV-1 infection at risk for primary infection and subsequent disease if CMV seronegative blood products are not provided for future transfusions. 相似文献
108.
Hans HCM Savelberg Nicolaas C Schaper Paul JB Willems Ton LH de Lange Kenneth Meijer 《BMC musculoskeletal disorders》2009,10(1):16
Background
Patients with diabetic polyneuropathy (DPN) are often confronted with ulceration of foot soles. Increased plantar pressure under the forefoot has been identified as a major risk factor for ulceration. This study sets out to test the hypothesis that changes in gait characteristics induced by DPN related muscle weakness are the origin of the elevated plantar pressures. 相似文献109.
110.
The TASK background K2P channels: chemo- and nutrient sensors 总被引:1,自引:0,他引:1
Specialized chemo- and nutrient-sensing cells share a common electrophysiological mechanism by transducing low O(2), high CO(2) and low glucose stimuli into a compensatory cellular response: the closing of background K(+) channels encoded by the K(2P) subunits. Inhibition of the TASK K(2P) channels by extracellular acidosis leads to an increased excitability of brainstem respiratory neurons. Moreover, hypoxic down-modulation of TASK channels is implicated in the activation of glomus cells in the carotid body. Stimulation of both types of cell leads to an enhanced ventilation and to cardiocirculatory adjustments. Differential modulation of TASK channels by acidosis and high glucose alters excitability of the hypothalamic orexin neurons, which influence arousal, food seeking and breathing. These recent results shed light on the role of TASK channels in sensing physiological stimuli. 相似文献