全文获取类型
收费全文 | 39040篇 |
免费 | 2568篇 |
国内免费 | 2164篇 |
专业分类
耳鼻咽喉 | 1534篇 |
儿科学 | 373篇 |
妇产科学 | 140篇 |
基础医学 | 5336篇 |
口腔科学 | 964篇 |
临床医学 | 3470篇 |
内科学 | 2447篇 |
皮肤病学 | 221篇 |
神经病学 | 9023篇 |
特种医学 | 1308篇 |
外国民族医学 | 2篇 |
外科学 | 6704篇 |
综合类 | 5028篇 |
预防医学 | 725篇 |
眼科学 | 2558篇 |
药学 | 1990篇 |
17篇 | |
中国医学 | 1138篇 |
肿瘤学 | 794篇 |
出版年
2024年 | 66篇 |
2023年 | 530篇 |
2022年 | 917篇 |
2021年 | 1257篇 |
2020年 | 1329篇 |
2019年 | 1157篇 |
2018年 | 1110篇 |
2017年 | 1387篇 |
2016年 | 1379篇 |
2015年 | 1332篇 |
2014年 | 2310篇 |
2013年 | 2358篇 |
2012年 | 1904篇 |
2011年 | 2101篇 |
2010年 | 1858篇 |
2009年 | 1736篇 |
2008年 | 1918篇 |
2007年 | 1914篇 |
2006年 | 1727篇 |
2005年 | 1482篇 |
2004年 | 1395篇 |
2003年 | 1270篇 |
2002年 | 1105篇 |
2001年 | 984篇 |
2000年 | 816篇 |
1999年 | 763篇 |
1998年 | 731篇 |
1997年 | 684篇 |
1996年 | 580篇 |
1995年 | 507篇 |
1994年 | 456篇 |
1993年 | 407篇 |
1992年 | 448篇 |
1991年 | 364篇 |
1990年 | 372篇 |
1989年 | 300篇 |
1988年 | 256篇 |
1987年 | 270篇 |
1986年 | 272篇 |
1985年 | 342篇 |
1984年 | 311篇 |
1983年 | 192篇 |
1982年 | 228篇 |
1981年 | 204篇 |
1980年 | 183篇 |
1979年 | 130篇 |
1978年 | 93篇 |
1977年 | 85篇 |
1976年 | 68篇 |
1975年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
101.
102.
目的探讨面神经颅外段的动脉来源及分布. 方法 15例新鲜尸体头颈部标本经双侧颈总动脉插管,加压注入红色乳胶或过氯乙烯填充剂,观察面神经颅外段的血供来源及分布. 结果面神经营养动脉来源于耳后动脉的茎乳动脉、颞浅动脉面神经支、面横动脉、颈外动脉上面神经支、颈外动脉下面神经支、面动脉后面神经支和面动脉前面神经支,其外径分别为(0.8±0.2) mm、(0.9±0.4) mm、(1.9±0.3) mm、(1.0±0.2) mm、(1.1±0.4) mm、(1.0±0.2) mm和(1.1±0.6) mm.各营养动脉除营养面神经外还发出分支相互吻合,构成了丰富的面神经血管网. 结论了解面神经颅外段动脉血供来源及分布,为避免腮腺咬肌区手术损伤面神经营养血管提供了解剖学基础. 相似文献
103.
Unidirectional fluxes of 45Ca, 36Cl, and of [3H]mannitol from blood into the sciatic nerve and cerebral cortex were determined from 5- and 15-min uptakes of these tracers after an intravenous (i.v.) bolus injection in awake rats. Rats were fed diets for 8 wk, that had either a low (0.01% wt/wt), normal (0.67%), or high (3%) Ca content. Plasma [Ca] was 32% less and 11% more in rats fed low (LOCA) and high Ca diets (HICA), respectively, than in rats fed a normal Ca diet (CONT). The mean permeability-surface area product (PA) of 45Ca at the blood-nerve barrier was about eightfold higher than at the blood-brain barrier in the same animals and did not differ significantly between groups (greater than 0.05). Mean PA ratios of 45Ca/36Cl for the blood-nerve and blood-brain barriers in CONT rats, 0.52 +/- 0.04 and 0.40 +/- 0.02, respectively, were not significantly different from corresponding ratios in LOCA and HICA groups, and corresponded to the aqueous limiting diffusion ratio (0.45). Our results show no evidence for concentration-dependent transport of Ca over a plasma [Ca] range of 0.8-1.4 mmol/liter at the blood-nerve barrier of the rat peripheral nerve, and suggest that Ca and Cl exchange slowly between nerve and blood via paracellular pathways. 相似文献
104.
Immunocytochemical and histochemical studies in the tiger salamander and bullfrog demonstrated the presence of luteinizing hormone-releasing hormone-like immunoreactive (LHRH-ir) material and acetylcholinesterase (AChE) in the terminal nerve (TN). Immunoreactive perikarya and processes were found within the olfactory, vomeronasal and trigeminal nerves and in the nasal epithelium. Central TN projections consisted of fibers terminating in the olfactory bulb and bundles that projected to another group of LHRH-ir perikarya in the preoptic region. Up to 4 weeks following hypophysectomy, the labeling intensity and number of TN-immunoreactive neurons were not altered. Acetylcholinesterase histochemistry in the salamander revealed two distinct groups of neurons associated with the TN: a lightly labeled group of fusiform perikarya was located in the olfactory nerve proper and a more heavily labeled group of larger oval perikarya was found within AChE-positive trigeminal fascicles in the ventral mucosa. This study has demonstrated that the amphibian TN follows olfactory, vomeronasal and trigeminal nerves to reach peripheral targets in the nasal mucosa. The projection of TN fibers to discrete olfactory bulb glomeruli, especially evident in the bullfrog, suggests that the TN functions in odor processing. The TN projection to the preoptic region in both of these amphibians implicates the TN in reproductive processes. 相似文献
105.
K. H. Vogelberg M. Mühl M. Köhler 《Journal of molecular medicine (Berlin, Germany)》1987,65(15):713-718
Summary Seventy-five diabetic and 40 nondiabetic subjects who where suffering from peripheral vascular disease were studied in order to determine whether the degree of the severity of their disease can be better calculated by Doppler ultrasound examinations of the peak velocity than by the systolic pressure of the peripheral bloodstream. In 46 examinations of normal controls the mean value of the peak velocity was 13.3±3.3 cm/s with a standard deviation of 15.4%±13.2% on one day and 16.1%±15.9% on different days. Considering patients with or without diabetes mellitus the velocity was significantly decreased in correlation to an increasing degree of severity of the vascular disease (P<0.001); however, the decrease was lower in diabetic than in nondiabetic subjects (6.9±2.8 vs 4.6±6.2,P<0.05). The systolic pressure hardly decreased, but remained higher in all stages of peripheral vascular disease of diabetics than in the nondiabetic subject (P<0.05 toP<0.005). There was a significant decrease of the systolic pressure only in diabetic subjects with the most advanced degree of the disease, i.e. stage IV (P<0.05).It is concluded from this study that Doppler ultrasound measurements of the peak velocity of the peripheral bloodstream are a useful parameter to calculate the degree of severity of the peripheral vascular disease. In addition, it is concluded than peak velocity is an even better prognostic indicator of peripheral vascular disease than is measurement of the systolic blood pressure at the feet.
Abkürzungen AVK periphere arterielle Verschlußkrankheit - USDI Ultraschall-Doppler-Index - MSBG maximale Blutströmungsgeschwindigkeit - HFV Herzfrequenzvariation 相似文献
Abkürzungen AVK periphere arterielle Verschlußkrankheit - USDI Ultraschall-Doppler-Index - MSBG maximale Blutströmungsgeschwindigkeit - HFV Herzfrequenzvariation 相似文献
106.
Elizabeth P. Eustis-Turf Joyce A. Benjamins Maurice J. Lefford 《Journal of neuroimmunology》1986,10(4):313-330
Sera from 43 leprosy patients were tested for antibodies that bound to normal human nerve. Thirty-eight percent showed positive staining as demonstrated by indirect immunofluorescence. Only 1 out of 30 control sera tested displayed similar staining. Western blots of myelin and neural intermediate filament (IF) proteins were tested with patient sera. Two of the anti-neural antibody (ANeAb)-positive leprosy sera bound to the P0 protein of PNS myelin. All 17 ANeAb-positive leprosy sera displayed 2 or more bands in the molecular weight range of Mr 45 000-55 000, when tested against IF proteins. One explanation for these findings is that leprosy patients produce antibodies to intermediate filament (IF) proteins released subsequent to the bacterial invasion of the peripheral nerves. The importance of these autoantibodies in the pathogenesis of leprosy is discussed. 相似文献
107.
体外培养诱导外周血淋巴细胞促进大鼠面神经再生的实验研究 总被引:1,自引:0,他引:1
目的:通过在神经缺损处局部回输体外分离培养纯化的淋巴细胞,了解此种方法促进面神经损伤修复的效果。方法:将20只Wistar大鼠的面神经颊支剪断并立即缝合(其余3支反折缝合)制成面神经损伤模型大鼠,将其分成淋巴细胞组和对照组,每组10只,每组再分成2周组和8周组。淋巴细胞组局部回输体外分离培养的外周血淋巴细胞,对照组作对照。于2周和8周测定面神经颊支-触须肌复合动作电位传导速度,辣根过氧化物酶(HRP)神经逆行示踪测定面神经核团的神经元阳性数目。结果:淋巴细胞组面神经颊支-触须肌复合动作电位传导速度8周时为0.64±0.07,与对照组(0.56±0.07)相比,差异有统计学意义(P<0.05)。HRP神经逆行示踪测定面神经核团神经元阳性数目,淋巴细胞组2周及8周与对照组同时间段相比差异均无统计学意义(均P>0.05)。结论:体外分离培养纯化的淋巴细胞在局部应用于神经损伤处对面神经再生修复可起一定的促进作用。 相似文献
108.
109.
兔坐骨神经挤压伤的MRI与SEP对比研究 总被引:3,自引:0,他引:3
目的:探讨磁共振成像和体感诱发电位以及两者结合在坐骨神经急性挤压伤中的诊断价值。方法:24只兔按钳夹力的不同随机分为A、B两组,左后肢为损伤侧,右后肢为对照侧,建立坐骨神经急性挤压伤模型,于伤后1、2、4、8周行MR扫描,同时行双侧体感诱发电位检查。结果:损伤侧24条神经,有23条MR显示异常,诊断正确率95.8%,假阴性率4.17%(1/24);24条损伤侧坐骨神经,有22条SEP显示异常,诊断正确率91.6%,假阴性率8.3%(2/24)。MRI与SEP对神经损伤的正确诊断率无统计学差异(P>0.05)。MRI与SEP结合起来,24条损伤神经均显示异常,诊断正确率100%。结论:MR与SEP检查可无创、准确地判断神经损伤,两者结合可明显提高神经损伤的正确诊断率,重复性好,可作为神经损伤的较好诊断手段。 相似文献
110.