全文获取类型
收费全文 | 2347篇 |
免费 | 115篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 16篇 |
妇产科学 | 15篇 |
基础医学 | 325篇 |
口腔科学 | 31篇 |
临床医学 | 114篇 |
内科学 | 580篇 |
皮肤病学 | 38篇 |
神经病学 | 181篇 |
特种医学 | 62篇 |
外科学 | 533篇 |
综合类 | 10篇 |
预防医学 | 53篇 |
眼科学 | 19篇 |
药学 | 263篇 |
中国医学 | 12篇 |
肿瘤学 | 219篇 |
出版年
2023年 | 20篇 |
2022年 | 32篇 |
2021年 | 49篇 |
2020年 | 45篇 |
2019年 | 35篇 |
2018年 | 38篇 |
2017年 | 43篇 |
2016年 | 38篇 |
2015年 | 51篇 |
2014年 | 67篇 |
2013年 | 92篇 |
2012年 | 115篇 |
2011年 | 132篇 |
2010年 | 67篇 |
2009年 | 57篇 |
2008年 | 98篇 |
2007年 | 124篇 |
2006年 | 144篇 |
2005年 | 159篇 |
2004年 | 183篇 |
2003年 | 141篇 |
2002年 | 154篇 |
2001年 | 46篇 |
2000年 | 47篇 |
1999年 | 48篇 |
1998年 | 42篇 |
1997年 | 35篇 |
1996年 | 23篇 |
1995年 | 29篇 |
1994年 | 20篇 |
1993年 | 23篇 |
1992年 | 25篇 |
1991年 | 14篇 |
1990年 | 16篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1984年 | 21篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1977年 | 10篇 |
1974年 | 6篇 |
1972年 | 7篇 |
1970年 | 5篇 |
1969年 | 7篇 |
排序方式: 共有2479条查询结果,搜索用时 15 毫秒
1.
Ryo Wakita Yuka Ohno Saori Yamazaki Hikaru Kohase Masahiro Umino 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2006,102(6):e28-e32
Two cases of vasovagal syncope (VVS) during venous access are reported. Both patients had a history of fainting episodes and experienced bradycardia with asystole, hypotension, and fainting. Pain and phobic stress during venous access triggered an increase in parasympathetic tone, resulting in bradycardia with asystole and hypotension in both cases. Hypotension and bradycardia likely caused cerebral hypoperfusion, leading to fainting. The intense parasympathetic tone triggered by somatic or emotional stress was likely responsible for directly depressing the sinus node, leading to asystole and bradycardia. Bradycardia with asystole progressing to syncope is a potentially fatal dysrhythmia in patients with cardiovascular disease or older patients with decreased cardiac function. Appropriate treatment for VVS includes the administration of intravenous fluids, vagolytics, ephedrine, and the rapid use of the Trendelenburg position. Intravenous fluids and atropine were used to treat the present patients. 相似文献
2.
Yuki Izawa Masanori Yoshizumi Keisuke Ishizawa Yoshiko Fujita Shuji Kondo Shoji Kagami Kazuyoshi Kawazoe Koichiro Tsuchiya Shuhei Tomita Toshiaki Tamaki 《Hypertension research》2007,30(11):1107-1117
Big mitogen-activated protein kinase 1 (BMK1), also known as extracellular signal-regulated kinase 5 (ERK5), is a newly identified member of the mitogen-activated protein (MAP) kinase family. Recently, several studies have suggested that BMK1 plays an important role in the pathogenesis of cardiovascular disease. To clarify the pathophysiological significance of BMK1 in the process of vascular remodeling, we explored the molecular mechanisms of BMK1 activation in vascular smooth muscle cells (VSMCs). From the results of co-immunoprecipitation and immunoblotting analyses, it was found that platelet-derived growth factor (PDGF), a known potent mitogen, activated BMK1 and triggered the Gab1-SHP-2 interaction in rat aortic smooth muscle cells (RASMCs). The abrogation of SHP-2 phosphatase activity by transfection of the SHP-2-C/S mutant suppressed PDGF-stimulated BMK1 activation. Infection with an adenoviral vector expressing dominant-negative MEK5alpha, which can suppress PDGF-stimulated BMK1 activation to the control level, inhibited PDGF-induced RASMC migration. Moreover, we observed an increase of BMK1 activation in injured mouse femoral arteries. From these findings, it is suggested that BMK1 activation leads to VSMC migration induced by PDGF via Gab1-SHP-2 interaction, and that BMK1-mediated VSMC migration may play a role in the pathogenesis of vascular remodeling. 相似文献
3.
4.
Hiroshi Uno Yoshihiro Izawa Kiyoshi Sagara Tamotsu Koyama Tokutaro Makita Chia-Yuan Hsu-Chang Mitsugi Sugiyama 《Journal of bone and mineral metabolism》1990,8(1):10-16
The effect of 1α-hydroxyvitamin D3 (1α(OH)D3) on the metabolic bone disorders developed in gastrectomized rats were investigated biochemically and histomorphologically.
1α(OH)D3 was suspended in 0.2 % Triton-X-100 aqueous solution after dissolving in a very small amount of ethanol, was given orally
to the rats for 10 weeks. The sham operated animals and the gastrectomy control animals received the vehicle alone. Gastrectomy
was followed by the development of the metabolic bone disorders after 10 weeks of observation. This was characterized by reduction
in ash content of the femur and histologically by a disappearance of the trabecular bone in tibial metaphysis. Decrease Ca
absorption from the intestines was demonstrated by a radiotracer technique. Biochemical studies showed significant decreases
in serum 25(OH)D concentration in gastrectomized rats. These findings suggest that gastrectomy partially impairs intestinal
absorption of calcium and results in a negative calcium balance, which may contribute to the development of bone metabolic
disorders in rats. The administration of 1α(OH)D3 increased dose-dependently serum calcium and Ca absorption from the intestine and prevented the development of bone metabolic
disorders histomorphologically. 相似文献
5.
Mariko Hosono H. Kobayashi Ryota Fujimoto Kazushige Tsutsui Yoshihiko Kotoura Tadao Tsuboyama Hikaru Hayashi Takashi Nakamura Junji Konishi 《Skeletal radiology》1997,26(9):525-528
Objective. To clarify the MRI features of parasymphyseal insufficiency fractures of the os pubis. Design and patients. MRI was performed in four postmenopausal women with parasymphyseal insufficiency fractures. The diagnosis was confirmed with
plain films in every patient. T1-weighted and T2-weighted images were obtained in four patients using a 1.5-T unit. Postcontrast
T1-weighted imaging was also done in three patients. Results and conclusions. MRI of pubic parasymphyseal insufficiency fracture characteristically demonstrates a hyperintense mass lesion with a hypointense
rim on T2-weighted imaging, showing peripheral and septal enhancement after contrast administration. It is important to have
this entity in mind in patients with osteoporosis, especially in patients with a history of pelvic irradiation for malignant
disease, so as not to misinterpret it as a chondroid tumor or bone metastasis. 相似文献
6.
7.
1. Single axons of pontine nucleus neurons (PN axons) receiving cerebral input were stained intra-axonally with horseradish peroxidase (HRP) in the cerebellum of cats. The axonal trajectory of single PN axons was reconstructed from serial sections of the cerebellum and the brain stem. 2. Axons were penetrated in the white matter near the dentate nucleus, and, after electrophysiological identification, PN axons were injected iontophoretically with HRP. The identification criteria for the PN axons were 1) their direct responses to stimulation of the contralateral pontine nucleus (PN), 2) their synaptic activation from the contralateral cerebral cortex, and 3) the decrease in threshold for evoking direct spikes in stimulation of the PN by conditioning stimuli applied in the cerebral cortex. 3. Two hundred thirty-three axons were electrophysiologically identified as PN axons receiving the input from the cerebral cortex. Ninety-six of them were stained successfully with HRP, and reconstructions were made from 40 well-stained PN axons. All of them gave rise to mossy fibers and terminated in the granular layer of the cerebellar cortex as typical mossy fiber rosettes. Out of these, 22 gave axon collaterals to the dentate nucleus. Virtually all of the axon branches observed in the dentate nucleus were axon collaterals of mossy fibers from the PN to the cerebellar cortex. In 7 of these 22 PN axons, cell bodies were retrogradely labeled with HRP, and all of them were found in the contralateral PN. 4. The stained-stem axons arising from the PN ran medially in the pons, crossed the midline, and then ascended dorsocaudally in the branchium pontis. After passing in the white matter anterior to or lateral to the dentate nucleus, they entered into the cerebellar cortex. On their way, one to three axon collaterals were given off from parent axons to the dentate nucleus. The diameter of these collaterals was very thin (mean, 0.6 microns), compared with the large diameter of the parent axons (mean, 2.1 microns). 5. Some axon collaterals were very simple and had only one terminal branch with or without short branchlets, whereas others were more complex, and single axon collaterals ramified before forming a terminal arborization. Axon collaterals of single PN axons mainly spread mediolaterally or dorsoventrally in the frontal plane but had a very narrow rostrocaudal extension. 6. Terminal branches usually bore swellings en passant along their length and one terminal swelling at their end. The number of swellings per axon collateral ranged 23-180 (116 +/- 52, mean +/- SD).(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
8.
9.
10.
Intracellular recordings of electrical activity were made from circular smooth muscle cells in small segments of tissue isolated from the guinea-pig stomach antrum. Every cell that was impaled exhibited a rhythmic generation of slow potentials. Experiments were carried out to test the effects of three different concentrations (1, 10 and 100 nM) of phorbol 12, 13-dibutyrate (PDBu) on these slow potentials and on the responses produced by acetylcholine (ACh), in the presence of nifedipine and N(omega)-nitro-L-arginine (nitroarginine), known inhibitors of L-type Ca-channels and nitric oxide synthase, respectively. The resting membrane potential was -62 +/- 7 mV, while the frequency and amplitude of the slow potentials were 1.6 +/- 0.1 cycle per min (cpm) and 33 +/- 1 mV, respectively. Application of 1 nM PDBu increased the frequency of slow potentials, with no significant change in the membrane potential and amplitude of slow potentials. At a concentration of 100 nM, PDBu depolarized the membrane by about 6 mV, and either decreased the amplitude and frequency of the slow potentials or abolished them. The amplitude and frequency of the slow potentials were not significantly changed in the presence of 10 nM PDBu. In the presence of chelerythrine (1-2 microM), a known inhibitor of protein kinase C (PKC), the increase in frequency of slow potentials by 1 nM PDBu and depolarization produced by 100 nM PDBu were not elicited. The increase in frequency of slow potentials by 100 nM ACh was inhibited by PDBu, in a concentration-dependent manner, and ACh-responses were abolished in the presence of 100 nM PDBu. These results indicate that PDBu has dual actions on the spontaneous activity of antral circular muscle, with low concentrations increasing and high concentrations inhibiting the frequency of the slow potentials. The former may be produced by activation of protein kinase C (PKC). As the ACh-induced excitation of slow potentials is inhibited by PDBu, a possible causal relationship between the inhibition and over-activation of PKC is considered. 相似文献