全文获取类型
收费全文 | 15834篇 |
免费 | 1969篇 |
国内免费 | 709篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 174篇 |
妇产科学 | 282篇 |
基础医学 | 4455篇 |
口腔科学 | 235篇 |
临床医学 | 1181篇 |
内科学 | 3090篇 |
皮肤病学 | 148篇 |
神经病学 | 1427篇 |
特种医学 | 252篇 |
外国民族医学 | 3篇 |
外科学 | 1554篇 |
综合类 | 2321篇 |
现状与发展 | 11篇 |
一般理论 | 1篇 |
预防医学 | 583篇 |
眼科学 | 196篇 |
药学 | 1512篇 |
5篇 | |
中国医学 | 166篇 |
肿瘤学 | 863篇 |
出版年
2024年 | 13篇 |
2023年 | 281篇 |
2022年 | 428篇 |
2021年 | 621篇 |
2020年 | 693篇 |
2019年 | 441篇 |
2018年 | 581篇 |
2017年 | 564篇 |
2016年 | 602篇 |
2015年 | 633篇 |
2014年 | 1071篇 |
2013年 | 970篇 |
2012年 | 965篇 |
2011年 | 985篇 |
2010年 | 957篇 |
2009年 | 963篇 |
2008年 | 716篇 |
2007年 | 783篇 |
2006年 | 743篇 |
2005年 | 641篇 |
2004年 | 541篇 |
2003年 | 469篇 |
2002年 | 472篇 |
2001年 | 398篇 |
2000年 | 364篇 |
1999年 | 282篇 |
1998年 | 185篇 |
1997年 | 139篇 |
1996年 | 161篇 |
1995年 | 146篇 |
1994年 | 139篇 |
1993年 | 145篇 |
1992年 | 190篇 |
1991年 | 241篇 |
1990年 | 187篇 |
1989年 | 160篇 |
1988年 | 157篇 |
1987年 | 103篇 |
1986年 | 52篇 |
1985年 | 58篇 |
1984年 | 29篇 |
1983年 | 20篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 17篇 |
1979年 | 19篇 |
1977年 | 12篇 |
1973年 | 14篇 |
1972年 | 12篇 |
1964年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Adenosine''s role in the genesis of bradyarrhythmias induced by acute myocardial hypoxia. 总被引:2,自引:0,他引:2
A close or even causal relation between myocardial adenosine and bradyarrhythmias during acute myocardial hypoxia was testified in guinea pig, rabbit and dog mainly by using specific competitive antagonist and synchronous quantitative analysis of 3 variables: intensity of myocardial hypoxia, degree of endogenous adenosine increment and severity of bradyarrhythmias. Results disclosed: A) striking resemblance of the bradyarrhythmias with hypoxic origin to those caused by exogenous adenosine, B) same locality of A-V conduction block induced by both myocardial hypoxia and exogenous adenosine, C) precise parallelism among the above-listed 3 variables with very high correlativity (r = 0.99, P < 0.01), D) frequent accompaniment of reversal of hypoxic bradyarrhythmias through resupply of 21% O2 with normalization of preexisted increase in myocardial adenosine, E) satisfactory blockade of hypoxic bradyarrhythmias by adenosine's specific antagonist--aminophylline and their augmentation by adenosine's uptake inhibitor--dipyridamole, F) close similarity of the characteristic curve representing relation among the above 3 variables to that among intensity of myocardial hypoxia, degree of endogenous adenosine increment and amount of coronary blood flow in which adenosine's role as a mediator has been well documented and G) reproducible persistence of bradyarrhythmias during myocardial hypoxia irrespective of preliminary vagotomy and atropinization, denoting independence of the occurrence of such dysarrhythmias upon vagal drive, suggestive of a mechanism other than vagotonia. We advocated that hypoxia-induced bradyarrhythmias was caused by increment in endogenous adenosine.
相似文献
93.
目的 :探讨十二指肠球部溃疡与红细胞天然免疫功能的关系。方法 :对 5 6例十二指肠球部溃疡患者采用免疫粘附酵母菌花环法和肿瘤红细胞花环试验测定其红细胞CR1活性。结果 :十二指肠球部溃疡患者与正常人相比 ,红细胞C3b受体花环率 (RBC C3bRR)、红细胞粘附肿瘤花环率 (RBC TRR)明显降低 (P <0 .0 5 ) ,红细胞免疫复合物花环率 (RBC ICR)明显增高 (P <0 .0 5 )。结论 :十二指肠球部溃疡患者红细胞免疫功能属继发性低下 ,红细胞免疫可能参与了十二指肠球部溃疡发生 ,加强红细胞天然免疫功能对于防治十二指肠球部溃疡可能有重要意义 相似文献
94.
95.
Masafumi Ogawa Yasuhiro Magata Yasuomi Ouchi Hidenao Fukuyama Hiroshi Yamauchi Jun Kimura Yoshiharu Yonekura Junji Konishi 《Brain research》1994,650(2):249-252
The effect of the cholinergic blocker, scopolamine on the cerebral blood flow (CBF) response to vibrotactile stimulation of a fore paw was studied using high-resolution positron emission tomography and H215O in 5 pentobarbital-anesthetized cats. Before scopolamine injection, the CBF response to the stimulation was found in the contralateral somatosensory cortex (mean ratio (contralateral/ipsilateral) control: stimulated1.02 ± 0.02: 1.17 ± 0.05; P < 0.01). After intravenous injection of scopolamine (0.35 mg/kg), the CBF response was abolished. However, the cerebral metabolic rate of glucose (CMRGlu) response to the same stimulation was unchanged after scopolamine injection in the same cats. We concluded that scopolamine abolishes the CBF response but not neuronal response to stimulation. We suggest that cholinergic mechanisms may play an important role for mediating CBF coupling to neuronal activity during physiological stimulation. 相似文献
96.
对食管癌高发区粮食中分离的互隔交链孢霉的毒素交链孢酚单甲醚(AME)在大鼠、小鼠体内的分布进行研究。给动物腹腔内注射氚标记的交链孢酚单甲醚(~3H-AME),然后在不同时间测各脏器的放射性。结果表明:在所测9个脏器中,2h肝脏含量最高,食管下段在大小鼠分别居第四和第三。但大小鼠分别在72、24h则以食管下段最高,说明AME及其代谢物在此清除较慢,即对其有较高的亲和力。 相似文献
97.
The effects of different doses of calcitonin gene-related peptide (CGRP) on passive avoidance behaviour were studied in male rats following its intracerebroventricular (i.c.v.) administration. Treatment with doses of 200 ng, 300 ng, 500 ng or 1 microgram was performed prior to learning, immediately and 6 h after the learning session and 30 min before the 24 h retention test. CGRP enhanced the avoidance latency in a dose-dependent manner at each time studied, with the exception of 6 h after the learning session. It is concluded that CGRP might be able to lengthen the passive avoidance latency by facilitating learning and memory formation. 相似文献
98.
Jin Hui-ming 《华中科技大学学报(医学英德文版)》1990,10(4):193-200
Summary The content of plasma fibronectin and tissue extractable fibronectin in normal rats was measured with rocket immunoelectrophoresis
and ELISA in the present study. The difference in tissue fibronectin distribution in various organs and the correlation between
distribution and content of fibronectin have been studied. We suggest that tissue fibronectin may be a complex component.
The change in plasma fibronectin reflects a dynamic balance existing between the tissue fibronectin pool and plasma fibronectin
pool in normal rats. Plasma fibronectin and tissue fibronectin concentrations are not static, and they can only be maintained
in a relatively stable state in normal rats. 相似文献
99.
Kaoru Hatanaka Xiang-An Li Ling Guo Toshiyuki Sakata Judith A. Gillissen Akira Yoshioka Akira Yamamoto 《Thrombosis research》1994,74(6):643-654
We have experienced a coagulation factor VIII-deficient patient whose plasma has normal protein S (PS) activity and masses of free PS and its bound form in complex with C4b-binding protein (C4BP). Although the patient's plasma showed a normal ratio of free PS to PS-C4BP complex in the presence of 5 mM EDTA, the plasma gave an abnormally retarding major C4BP peak together with a major PS peak in the crossed immunoelectrophoresis (CIE) in the presence of 2 mM CaCl2. It was revealed that the major peak was formed by a mixture of PS-C4BP complex and free form. The addition of normal human plasma (NHP) to the patient's plasma inhibited the retardation of the major PS-C4BP complex. These suggest that the patient's plasma lacks some component(s) to inhibit Ca2+-dependent association of PS with C4BP. 相似文献
100.
A. CalabrO B. Orsini S. Milani M. Psilogenis C. Surrenti 《Pharmacological research》1992,26(4):403-407
The effect of sulglycotide, a polysulphated glycopeptide isolated from pig duodenum, on PGE2, 6-ketoPGF1 alpha and TxB2 production from isolated biopsy specimens of human antral mucosa was investigated in vitro, in comparison with carbenoxolone. In addition to a tendency toward increased PGE2 production just short of statistical significance, both sulglycotide and carbenoxolone significantly increased 6-ketoPGF1 alpha accumulation in the incubation medium. TxB2 levels were not significantly modified by the two drugs. Therefore, changes in the prostanoid production by human antral mucosa could, at least partially account for the cytoprotective effects of sulglycotide in man. 相似文献