全文获取类型
收费全文 | 95509篇 |
免费 | 9822篇 |
国内免费 | 6128篇 |
专业分类
耳鼻咽喉 | 860篇 |
儿科学 | 1559篇 |
妇产科学 | 590篇 |
基础医学 | 6578篇 |
口腔科学 | 1767篇 |
临床医学 | 11230篇 |
内科学 | 9557篇 |
皮肤病学 | 1011篇 |
神经病学 | 2653篇 |
特种医学 | 3901篇 |
外国民族医学 | 5篇 |
外科学 | 8739篇 |
综合类 | 24727篇 |
现状与发展 | 24篇 |
一般理论 | 4篇 |
预防医学 | 10739篇 |
眼科学 | 1076篇 |
药学 | 11437篇 |
119篇 | |
中国医学 | 10087篇 |
肿瘤学 | 4796篇 |
出版年
2024年 | 425篇 |
2023年 | 1240篇 |
2022年 | 2941篇 |
2021年 | 3696篇 |
2020年 | 3352篇 |
2019年 | 2072篇 |
2018年 | 2242篇 |
2017年 | 2825篇 |
2016年 | 2482篇 |
2015年 | 4071篇 |
2014年 | 5067篇 |
2013年 | 6254篇 |
2012年 | 8770篇 |
2011年 | 9031篇 |
2010年 | 8144篇 |
2009年 | 7072篇 |
2008年 | 7247篇 |
2007年 | 6852篇 |
2006年 | 6264篇 |
2005年 | 4988篇 |
2004年 | 3714篇 |
2003年 | 3468篇 |
2002年 | 2836篇 |
2001年 | 2370篇 |
2000年 | 1731篇 |
1999年 | 727篇 |
1998年 | 242篇 |
1997年 | 233篇 |
1996年 | 168篇 |
1995年 | 128篇 |
1994年 | 133篇 |
1993年 | 74篇 |
1992年 | 72篇 |
1991年 | 87篇 |
1990年 | 62篇 |
1989年 | 52篇 |
1988年 | 30篇 |
1987年 | 47篇 |
1986年 | 37篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 30篇 |
1982年 | 20篇 |
1981年 | 8篇 |
1979年 | 13篇 |
1977年 | 10篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1971年 | 8篇 |
1969年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
61.
Emphysematous lung destruction by cigarette smoke. The effects of latent adenoviral infection on the lung inflammatory response. 总被引:9,自引:0,他引:9
Bernard Meshi Timothy Z Vitalis Diana Ionescu W Mark Elliott Chun Liu Xiang-Dong Wang Shizu Hayashi James C Hogg 《American journal of respiratory cell and molecular biology》2002,26(1):52-57
This study was designed to test the hypothesis that cigarette smoke-induced inflammation and emphysema are amplified by the presence of latent adenoviral (Ad) infection, and to determine whether this emphysematous process can be reversed by all-trans-retinoic acid (RA) treatment. The results confirm that in guinea pigs, chronic cigarette-smoke exposure caused lesions similar to human centrilobular emphysema. They also show that latent Ad infection combined with cigarette-smoke exposure caused an excess increase in lung volume (P < 0.001), air-space volume (P < 0.001), and lung weight (P < 0.01), and further decrease in surface-to-volume ratio (P < 0.001) compared with smoke exposure alone. RA treatment failed to reverse these emphysematous changes. Analysis of inflammatory response in parenchymal and airway tissue showed that smoking caused an increase of polymorphonuclear leukocytes (PMNs) (P < 0.0002), macrophages (P < 0.001), and CD4 cells (P < 0.0009), and that latent Ad infection independently increased PMNs (P < 0.001), macrophages (P = 0.003), and CD8 cells (P < 0.001). We conclude that latent Ad infection amplifies the emphysematous lung destruction and increases the inflammatory response produced by cigarette-smoke exposure. In this study, the increase in CD4 was associated with cigarette smoke and the increase in CD8 cells with latent Ad infection. 相似文献
62.
Isometric and isokinetic torque curves at the knee joint 总被引:1,自引:0,他引:1
Isometric and isokinetic torques of bilateral quadriceps and hamstrings were measured with Isokinetic Rehabilitation and Testing System (Model No. Cybex 340) on 40 normal untrained subjects, 20 males and 20 females, ranging between the ages of 23 and 35 years. The mean peak isometric and isokinetic torque values of both muscle groups showed no significant differences between dominant (right) and nondominant (left) limbs in both sexes; however there were significant differences between the male and the female. As the angular velocity increased, the peak torque significantly decreased, and the point of peak torque output occurred significantly later in the range of motion for quadriceps and hamstrings (p less than 0.01). There were no significant changes in the hamstrings to quadriceps (H/Q) ratios as the angular velocity increased. However, there were significant differences of mean H/Q ratio between male and female (p less than 0.01). Height had significant positive correlation with peak isometric and isokinetic torques for both quadriceps and hamstrings (p less than 0.01). Weight was found to correlate significantly with peak isometric and isokinetic torques (p less than 0.01). The mean isometric torques were significantly higher than the mean isokinetic torques for any joint angles in both sexes (p less than .01). 相似文献
63.
目的 在肌肉等效体模及Beagle犬颈段食管中测定ZRL—Ⅱ型食管腔内加热辐射器的温度分布,探讨其热场分布能否满足食管癌加热治疗的临床需要。方法 ①在肌肉等效体模中测定ZRL—Ⅱ型食管腔内射频加热辐射器的温度分布,②Beagle犬用氯胺酮麻醉、固定。将腔内加热辐射器插入食管腔内,加热45min后分层解剖犬的颈部,同时测量食管外壁、气管、食管周围软组织中的温度。结果 ①在肌肉等效体模中距离导管囊表面1cm的环形体内的温度在43.2℃~43.6℃之间;在距离导管囊表面2cm的环形体内的温度在42.6℃~43.3℃之间,在距离导管囊表面3cm的环形体内的温度在42.6℃~42.8℃之间。②测得Beagle犬颈段食管腔内和外壁的温度为43.5℃,气管内为38.0℃,主动脉旁38.0℃,距食管外壁1cm处的软组织温度为40-3℃,距食管外壁2cm处的软组织温度为39.0℃,而颈部皮下的温度是37.5℃。结论 ①ZRL-Ⅱ型射频食管腔内加热辐射器的热场分布满足临床食管腔内加热的需要,②体模测定与活体动物测定,热场分布存在一定差异,需进一步研究。 相似文献
64.
We report on the antileukemia effect of interleukin 2 (IL2) on different immune cells from 22 patients with chronic myeloid leukemia (CML). Bone marrow cells from these patients were first cultured in modified long-term bone marrow culture medium for several days, then separately cultured with lymphokine activated killer cells (LAK), cytokine-induced killer cells (CIK), and dendritic cell cocultured CIK (DC-CIK) for another 1-2 days. They were then detected for presence of the Philadelphia chromosome (Ph) by cytogenetic analysis and fluorescence in situ hybridization (FISH). The percentage of Ph-chromosome-positive cells in the bone marrow mononuclear cells after culturing with CIK and DC-CIK was significantly lower than that after culturing with IL2 or LAK. Our results demonstrate that cytogenetics and FISH are useful techniques for the evaluation of the anti-CML effect of immune cells and that CIK or DC-CIK can be appropriate candidates for adoptive immune cell therapy in vivo or for leukemia cell purging ex vivo. 相似文献
65.
骨组织工程种子细胞的研究进展 总被引:2,自引:0,他引:2
郭宗科 《国际生物医学工程杂志》2002,25(6):262-266
随着骨组织工程研究的进展 ,选择什么细胞作为其种子细胞成为近年来研究的热点。目前 ,骨组织工程应用中种子细胞有五种来源 :骨、骨膜、骨髓、骨外组织和早期胚胎。本文介绍了五种来源种子细胞的研究状况 ,并对种子细胞各自存在的问题及应用前景进行了分析。 相似文献
66.
TLR2和TLR4在原发性肝癌中的表达 总被引:1,自引:0,他引:1
目的:本研究通过检测原发性肝癌Toll样受体2(TLR2)和Toll样受体4(TLR4)的表达,分析其与临床病理生理因素的关系,探讨TLR2,TLR4在原发性肝癌疾病过程中的可能作用。方法:采用免疫组化法和实时荧光定量PCR分别在蛋白水平及mRNA水平检测原发性肝癌组织和配对癌旁组织TLR2、TLR4的表达。结果:原发性肝癌组织在蛋白水平和mRNA水平TLR2和TLR4的表达均明显低于癌旁组织(P<0.01)。但免疫组化结果显示不论是肝癌组织还是癌旁组织,TLR2和TLR4的表达均明显高于正常肝组织(P<0.01,P<0.05),有门静脉分支癌栓的患者癌组织TLR4的表达强度低于无门静脉分支癌栓的患者(P<0.05)。结论:肝癌组织TLR2和TLR4的表达与癌旁组织相比受到相对抑制,但高于正常肝组织,TLR2和TLR4信号途径可能参与了原发性肝癌的病理过程。 相似文献
67.
68.
Chun Jiang Theodore R. Cummins Gabriel G. Haddad 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1994,100(3):407-420
It is well known that neuronal firing properties are determined by synaptic inputs and inherent membrane functions such as
specific ionic currents. To characterize the ionic currents of brainstem cardio-respiratory neurons, cells from the hypoglossal
(XII) nucleus and the dorsal motor nucleus of the vagus (DMX) were freshly dissociated and membrane ionic currents were studied
under whole-cell voltage and current clamp. Both of these neurons showed a TTX-sensitive Na+ current with a much larger current density in XII than DMX neurons. This Na+ current had two (fast and slow) distinct inactivation decay components. The ratio of the magnitudes of the fast to slow component
was roughly two-fold greater in DMX than in XII cells. Both DMX and XII neurons also showed a high voltage-activated Ca2+ current, but this current density was significantly greater (three-fold) in DMX than XII neurons. A relatively small amount
of low-voltage activated Ca2+ current was also observed in DMX neurons, but not in the majority of XII cells. A transient and a sustained outward current
components were observed in DMX cells, but only sustained currents were present in XII neurons. These outward currents had
a reversal potential of about − 70 mV with 3 mM external K+ and −30 mV with 25 mM K+, and substitution of K+ with cesium and tetraethylammonium suppressed more than 90% the outward currents, indicating that most outward currents were
carried by K+. The transient outward current consisted of two components with onesensitive to 4-aminopyridine and the other to intracellular
Ca2+. In XII neurons, BRL 38227 (lemakalim), an ATP-sensitive K+ (KATP) channel activator, increased the sustained K+ currents by 10% of control, and glibenclamide, a KATP channel blocker, decreased the sustained K+ currents by 20%. Evidence for the presence of an inward rectifier K+ current was also obtained from both XII and DMX neurons. These results on XII and DMX neurons indicate that (1) the methods
used to dissociate neurons provide a useful means to overcome voltage clamp technical difficulties; (2) ion channel characteristics
such as density and biophysical properties of DMX neurons are very different from those of XII neurons; and (3) several newly
discovered membrane ionic currents are present in these cells. 相似文献
69.
Brain abscess. A study of 45 consecutive cases 总被引:9,自引:0,他引:9
Clinical features, findings of diagnostic studies, results of therapy, and prognostic factors were analyzed in 45 patients with brain abscesses. The number of patients diagnosed yearly has increased since CT scanning became available, but despite the enhanced sensitivity, the time from either onset of symptoms or hospital admission until initiation of therapy was not decreased and there was no dramatic effect upon morbidity or mortality in this series. Infections of paranasal sinuses, ears, lungs, and odontogenic foci were predisposing factors in approximately 70% of cases. Single abscesses, present in 75% of patients, were distributed equally in both hemispheres, with more than half in the frontal and parietal lobes. Common signs and symptoms included headache, fever, chills, seizures, nausea, vomiting, altered sensorium, nuchal rigidity, and localizing neurologic signs. Blood cultures were positive in 11%. Lumbar puncture rarely provided data from which a diagnosis could be established; CSF cultures were positive in only 7% of patients, and there was a 15% temporally associated incidence of brain herniation and death. Diagnostic information was most readily obtained using imaging techniques such as CT and 99mTc scanning, and arteriography was invasive and of no added value. CT scans are however, often initially negative in patients presenting with clinical signs of meningitis presumably following rupture of an abscess into the subarachnoid space, and the average time for changes to appear on CT scan is 9 days. It is, therefore, recommended that when the clinical assessment suggests the possibility of brain abscess the patient be treated empirically with antibiotics and that lumbar puncture be performed only after thoughtful assessment of the risk-to-benefit ratio for each patient. Causative organisms were isolated from more than 80% of abscesses despite prior antibiotic treatment; more than half grew a single pathogen, most commonly streptococci. Anaerobic and microaerophilic bacteria accounted for 62% of all isolates, and were the only organisms in 33% of patients. Computerized tomographic scans in 30 patients showed "ring-enhancing" lesions, nodular enhancement, or areas of low attenuation. Complete resolution of abscesses on CT scans rarely occurred during hospitalization and took as long as 5 months. Decrease in the size of abscesses on CT scan correlated well with clinical improvement and was seen within a week when abscesses were excised, but was often not obvious for 6 to 8 weeks if antibiotics were used alone.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
70.
糖尿病足溃疡是糖尿病严重的破坏性并发症,致残率及致死率逐年增高,严重威胁人类身心健康。中医药治疗糖尿病足溃疡,注重辨证论治与整体观念相结合,不仅能改善中医证候,更能在加速创面愈合的同时减少创面的复发,一定程度上延缓了糖尿病足溃疡的进一步恶化,降低其致残率及致死率。现代研究发现,糖尿病足溃疡难以愈合与各种细胞因子如炎症因子、生长因子、趋化因子等分布异常密切相关;随着现代医学对中医药研究的不断深入,中药单体及复方调控细胞因子治疗糖尿病足溃疡已成为研究热点,该文通过对目前国内外研究现状进行归纳,得出以下总结:(1)芝麻酚、栀子苷、当归补血汤、紫朱软膏等调节肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1、IL-6、IL-10等炎症因子,抑制创面炎症。(2)白芷、丹酚酸B、四效散、壮药拔毒生肌膏等调节血管内皮生长因子(VEGF)、血小板衍生生长因子(PDGF)、转化生长因子(TGF)、表皮生长因子(EGF)等生长因子,促进创面胶原沉积及血管新生。(3)芍药苷、隐丹参酮、蜂毒、回阳生肌汤等调节CXC趋化因子配体(CXCL)1、CXCL2、CC趋化因子配体(CCL)2、CCL3、基质细胞衍生... 相似文献