全文获取类型
收费全文 | 82649篇 |
免费 | 9654篇 |
国内免费 | 213篇 |
专业分类
耳鼻咽喉 | 891篇 |
儿科学 | 2135篇 |
妇产科学 | 3190篇 |
基础医学 | 10637篇 |
口腔科学 | 1806篇 |
临床医学 | 21147篇 |
内科学 | 14924篇 |
皮肤病学 | 1019篇 |
神经病学 | 6637篇 |
特种医学 | 2848篇 |
外国民族医学 | 45篇 |
外科学 | 9324篇 |
综合类 | 573篇 |
一般理论 | 83篇 |
预防医学 | 6652篇 |
眼科学 | 1228篇 |
药学 | 4715篇 |
中国医学 | 163篇 |
肿瘤学 | 4499篇 |
出版年
2023年 | 950篇 |
2022年 | 551篇 |
2021年 | 1248篇 |
2020年 | 1250篇 |
2019年 | 1114篇 |
2018年 | 2180篇 |
2017年 | 2096篇 |
2016年 | 2307篇 |
2015年 | 2554篇 |
2014年 | 2833篇 |
2013年 | 4050篇 |
2012年 | 3417篇 |
2011年 | 3788篇 |
2010年 | 3257篇 |
2009年 | 3196篇 |
2008年 | 3463篇 |
2007年 | 3502篇 |
2006年 | 3502篇 |
2005年 | 3245篇 |
2004年 | 3263篇 |
2003年 | 2948篇 |
2002年 | 2969篇 |
2001年 | 2649篇 |
2000年 | 2505篇 |
1999年 | 2423篇 |
1998年 | 1449篇 |
1997年 | 1422篇 |
1996年 | 1276篇 |
1995年 | 1234篇 |
1994年 | 961篇 |
1993年 | 936篇 |
1992年 | 1705篇 |
1991年 | 1639篇 |
1990年 | 1580篇 |
1989年 | 1509篇 |
1988年 | 1248篇 |
1987年 | 1236篇 |
1986年 | 1170篇 |
1985年 | 1106篇 |
1984年 | 799篇 |
1983年 | 751篇 |
1982年 | 541篇 |
1981年 | 531篇 |
1980年 | 432篇 |
1979年 | 710篇 |
1978年 | 435篇 |
1977年 | 423篇 |
1975年 | 412篇 |
1974年 | 450篇 |
1972年 | 422篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
B T Hyman J E Flory S E Arnold G W Van Hoesen R L Schelper H Ghanbari H Haigler 《Journal of geriatric psychiatry and neurology》1991,4(4):231-235
A quantitative assay for ALZ-50 immunoreactivity was evaluated in samples of superior temporal gyrus taken at autopsy from 13 Alzheimer patients and 11 controls. The assayable immunoreactivity appears to be stable for at least 24 hours postmortem but was lost with formalin fixation. The mean value of the Alzheimer patients was tenfold higher than that of the controls (P less than .002). The values of four Alzheimer samples overlapped with the low levels seen in controls, but no controls had elevated levels. In this sample population, therefore, the assay had a sensitivity of 69% and specificity of 100%. 相似文献
64.
65.
The absolute activities of the pure beta-emitters 89Sr and 90Y have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number of radionuclides that have been standardized by this non-extrapolation liquid scintillation (LS) method. Both measurements were carried out within the framework of international key comparisons under the auspices of the International Bureau of Weights and Measures (BIPM). The TDCR results agreed well with those of other participating national laboratories, most using alternative (tracer) methods. 相似文献
66.
67.
68.
69.
70.
Neuronal cell bodies in the hypothalamic paraventricular nucleus mediate stress-induced renin and corticosterone secretion 总被引:1,自引:0,他引:1
The present studies were undertaken to determine the involvement of neurons in the hypothalamic paraventricular nucleus (PVN) in stress-induced renin secretion. The stressor was a 10-min conditioned emotional response (CER) paradigm. Bilateral electrolytic lesions in the PVN prevented the stress-induced increase in plasma renin activity (PRA), and plasma renin concentration (PRC). Stress-induced corticosterone secretion was also blocked, supporting the histological verification and suggesting that the lesion included corticosterone-releasing factor neurons in the PVN. Stress-induced renin secretion appears to be restricted to the PVN, as electrolytic lesions in the nucleus reuniens, dorsal and caudal to the PVN, did not prevent the stress-induced increase in either PRA or PRC. The next step was to determine whether cell bodies in the PVN or fibers of passage through the PVN mediate the stress-induced increase of these hormones. For this purpose, bilateral stereotaxic injections of the cell-selective neurotoxin ibotenic acid (10 micrograms/microliter; 0.3 microliters per side) were performed 14 days prior to the stress procedure. Histological evaluation of the tissue revealed cell death and lysis in the PVN. Ibotenic acid injection into the PVN prevented the effect of stress on PRA, PRC and corticosterone levels. None of the lesions prevented the stress-induced rise in plasma prolactin concentration. These results suggest that neurons in the PVN play an important role in mediating stress-induced increases in renin and corticosterone but not prolactin secretion. 相似文献