全文获取类型
收费全文 | 81488篇 |
免费 | 7505篇 |
国内免费 | 5353篇 |
专业分类
耳鼻咽喉 | 575篇 |
儿科学 | 1026篇 |
妇产科学 | 1241篇 |
基础医学 | 9843篇 |
口腔科学 | 1588篇 |
临床医学 | 10364篇 |
内科学 | 12802篇 |
皮肤病学 | 858篇 |
神经病学 | 4410篇 |
特种医学 | 3102篇 |
外国民族医学 | 32篇 |
外科学 | 7784篇 |
综合类 | 12995篇 |
现状与发展 | 14篇 |
一般理论 | 12篇 |
预防医学 | 5532篇 |
眼科学 | 2118篇 |
药学 | 8745篇 |
80篇 | |
中国医学 | 4328篇 |
肿瘤学 | 6897篇 |
出版年
2024年 | 330篇 |
2023年 | 1298篇 |
2022年 | 3199篇 |
2021年 | 4068篇 |
2020年 | 3083篇 |
2019年 | 2624篇 |
2018年 | 2815篇 |
2017年 | 2520篇 |
2016年 | 2371篇 |
2015年 | 3604篇 |
2014年 | 4375篇 |
2013年 | 4116篇 |
2012年 | 6196篇 |
2011年 | 6519篇 |
2010年 | 4209篇 |
2009年 | 3326篇 |
2008年 | 4464篇 |
2007年 | 4329篇 |
2006年 | 3885篇 |
2005年 | 3829篇 |
2004年 | 2761篇 |
2003年 | 2510篇 |
2002年 | 2244篇 |
2001年 | 1835篇 |
2000年 | 1914篇 |
1999年 | 2014篇 |
1998年 | 1338篇 |
1997年 | 1325篇 |
1996年 | 1027篇 |
1995年 | 1010篇 |
1994年 | 811篇 |
1993年 | 519篇 |
1992年 | 575篇 |
1991年 | 527篇 |
1990年 | 447篇 |
1989年 | 420篇 |
1988年 | 335篇 |
1987年 | 329篇 |
1986年 | 261篇 |
1985年 | 229篇 |
1984年 | 141篇 |
1983年 | 96篇 |
1982年 | 87篇 |
1981年 | 61篇 |
1980年 | 57篇 |
1979年 | 48篇 |
1978年 | 22篇 |
1977年 | 28篇 |
1976年 | 28篇 |
1975年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
34例高血压病患者服国产吲达帕胺后,血压持续缓慢下降,TPR显著下降,血浆肾素活性(RA)、血管紧张素Ⅱ(AT-Ⅱ)和醛固酮(ADS)浓度显著增高,而心率及血儿茶酚爱(CA)水平无显著变化。治疗4周对全轿Cd,Pb,红细胞(RBC)及血浆Zn,Cu,Na,K,Mg浓度无显著影响。其总疗效为88.24%,表明国产吲达帕胺是一种疗效显著而副作用低的降压药物。 相似文献
92.
T.-H. ZHOU X.-H. REN D.-L. YIN Y.-L. WU M. Li C.-Z. Lu D.-C. Wu Y.-Q. Wu Y.-Q. PENG Y.-P. WANG L. MA G. PEI 《Acta anaesthesiologica Scandinavica》1997,41(8):1077-1079
Congenital analgesia is a rare genetic disorder. We report here that a 12-year-old boy was able to recover from congenital insensitivity to pain. Neurological examinations revealed that there was a 'stocking' distribution of pain decrement on the lower extremities under the patient's knee joints. Magnetic Resonance Imaging (MRI) of his brain showed gyrus thinning with sulcus widening at both sides of the parietal lobe. Southern blot hybridization probed with cDNAs of various opioid receptors did not detect any significant abnormality. Our results suggest that this rare case may not be genetically determined. 相似文献
93.
94.
应用以化学交联法制备的布鲁氏菌16M抗原-羧化胶乳制剂的羧化胶乳凝集试验(LAT)、试管凝集试验(SAT)、虎红平板凝集试验(RBPT)以及酶联免疫吸附试验(ELISA)、半胱氨酸凝集试验(CYT),对在四省布鲁氏菌病疫区收集的部分人、畜血清中布氏菌抗体进行对比检测。结果表明,LAT较之RBPT具有更高的特异性;与SAT相比,无论阳性或阴性符合率均较一致。另外,LAT可检测血清中IgG、IgM两类布氏菌特异性抗体。因而本试验对人、畜布病的诊断具有特异、敏感和简便的优点,更宜在基层推广应用。 相似文献
95.
Adultacuteleukemia (AL)isoneofthemostcommonmalignanttumorsofhematology .Withtherecentprogressinchemotherapyandsupportivether apy ,theremissionandsurvivalrateinALhavebeenmarkedlyimproved .However ,drugresistanceandrelapsearestillimportantfactorsaffectinglongsur vivalofthese patients .Theabnormalregulationofcellcycleisanotherfactorthatcannotbeignoredex ceptformultipledrugresistance (MDR) .WedetectcyclinA ,multidrugresistantgene (mdrl) ,topoiso meraseⅡα(TopⅡα)andbcl 2inadultpatientswithA… 相似文献
96.
乌贼墨诱生小鼠细胞毒因子活性的检测 总被引:11,自引:2,他引:9
吕昌龙 《中国医科大学学报》1994,23(4):322-323
用乌贼墨处理小鼠后,采集血清。经体外细胞毒实验证明:乌贼墨诱生的血清对人和鼠的肿瘤细胞株均有不同程度的杀伤作用。这一结果提示:乌贼墨可能具有诱生内源性细胞毒因子产生的活性。 相似文献
97.
Vaccination of Lewis rats with temperature-sensitive mutants of Mycoplasma pulmonis: adoptive transfer of immunity by spleen cells but not by sera. 总被引:1,自引:1,他引:0 下载免费PDF全文
Temperature-sensitive mutant vaccines protect rats against Mycoplasma pulmonis infection. The role of the humoral or cellular immune response in resistance to mycoplasma infection was investigated by adoptive-transfer experiments. Spleen cells from Lewis rats vaccinated but not challenged with wild-type organisms (vaccinated) and spleen cells from rats vaccinated (or not) and challenged were effective in preventing syngeneic recipients from developing respiratory disease. There was also a significant reduction in the incidence and number of challenging organisms in the respiratory system. In contrast, sera from the same donors had no detectable effect on the number of mycoplasmas recovered or on lesion development in the respiratory tract. We conclude that cellular immunity rather than humoral immunity generated in vaccinated rats confers protection against subsequent infection. 相似文献
98.
David S. K. Lu Shantanu Sinha John Lucas Keyvan Farahani Robert Lufkin Klaus Lewin 《Journal of magnetic resonance imaging : JMRI》1997,7(2):303-308
The purpose of this study was to test the feasibility of MR-guided percutaneous ethanol ablation of liver tissue on a .2-T open MR scanner. Needles were placed by MR guidance first into an ex vivo sheep liver and then into livers of three anesthetized pigs, and injection of 10 ml of 96% alcohol was performed. T1 fast low-angle shot (FLASH), T2 turbo spin echo (TSE), and T1 spin echo (SE) images were obtained after incremental volumes of injection. In one pig, simultaneous injection of saline into normal liver was also performed with subsequent pathological correlation. Ethanol-infiltrated liver was hypointense to liver on all sequences, whereas saline caused no tissue signal changes on T1 SE and either isointense or hyperintense changes on T2 TSE images. Pathological examination confirmed ethanol-induced acute liver changes as compared with the control. MR guidance of needle placement and monitoring of ethanol effects on liver tissue is feasible. This may have implications for potential MR-guided hepatic tumor ablation. 相似文献
99.
Several types of chronic pain syndromes are effectively treated with sodium channel blockers such as lignocaine. Further investigation of this therapeutic modality would be facilitated by refinement of the parameters describing lignocaine distribution and elimination. This would allow precise lignocaine infusion by a computer-controlled infusion to attain and maintain stable target lignocaine concentrations. Arterial blood samples were obtained at frequent intervals during a computer-controlled infusion of lignocaine in 12 adult human volunteers. Plasma lignocaine concentrations of 1, 2, 3, 4 and 5 microg/ml were targeted for 15 min at each concentration. A three-compartment mammillary pharmacokinetic model best described the resulting concentration vs time profile. A population pharmacokinetic analysis was performed using three different techniques; the two-stage, pooled and mixed effects modelling. There was marked overshoot of the plasma concentration above the target prior to refinement of the pharmacokinetic parameters. The best parameters of a three-compartment mammillary model fit to the measured concentration using the pooled data approach were: V(1) = 7.44, V(2) =11.5 and V(3) = 97.71; Cl(1) = 0.585, Cl(2) = 2.23 and Cl(3) =1.64 l/min. Similarly calculated parameters using NONMEM were V(1) = 6.99, V(2) =12.2 and V(3) =1341; Cl(1) = 0.703, Cl(2) =1.24 and Cl(3) =1.49 l/min. The addition of age as a covariate of the pharmacokinetic parameters improved the model in both cases. Height, lean body mass and body surface area as covariates of the pharmacokinetic parameters did not improve the predicted value of the model. Prospective testing of the pharmacokinetic parameters will be required to define whether they function well. The refinement of pharmacokinetic parameters for the computer-controlled intravenous infusion of lignocaine will facilitate further research in pain therapy. Published lignocaine pharmacokinetic values have a relatively large central volume of distribution, and hence, when implemented as a computer-controlled infusion, result in dramatic overshoot shortly after targeting a higher plasma concentration. In light of the long-lasting pain relief provided by sodium channel blockade in neuropathic pain states, overshoot of plasma concentrations must be avoided if the concentration vs effect relationship is to be defined. 相似文献
100.
Miguel Cordeiro Pedro Monteiro Dinis Vieira Francisco Parente Nuno Devesa José Moura Luís Providência 《Revista portuguesa de cardiologia》2004,23(3):399-441
Pulmonary embolism (PE) is an important health problem and often a major clinical challenge, not only because of the low specificity of its clinical manifestations but also because of the increasing number of medical circumstances that are risk factors for this illness and the importance of early identification, since prompt and appropriate treatment can decrease mortality from this disease by about 25%. In recent years research on PE has been extensive, directed mainly at trying to determine and characterize its risk factors, establish new clinical probability algorithms, develop new diagnostic methods and put existing ones into perspective, seek new therapeutic approaches (pharmacological and non-pharmacological), and above all establish protocols that can guide the clinician from the stage of clinical suspicion to measures to prevent recurrence. It was the authors' aim to review the most significant literature on this subject, in order to produce a text that reflects the state of the art concerning PE and that can be used as a guide in the clinical approach to this pathology. 相似文献