全文获取类型
收费全文 | 129327篇 |
免费 | 12529篇 |
国内免费 | 9228篇 |
专业分类
耳鼻咽喉 | 1005篇 |
儿科学 | 1353篇 |
妇产科学 | 976篇 |
基础医学 | 12843篇 |
口腔科学 | 2405篇 |
临床医学 | 16281篇 |
内科学 | 17661篇 |
皮肤病学 | 1065篇 |
神经病学 | 5988篇 |
特种医学 | 5136篇 |
外国民族医学 | 71篇 |
外科学 | 13783篇 |
综合类 | 27093篇 |
现状与发展 | 34篇 |
一般理论 | 8篇 |
预防医学 | 10407篇 |
眼科学 | 3212篇 |
药学 | 13953篇 |
102篇 | |
中国医学 | 8243篇 |
肿瘤学 | 9465篇 |
出版年
2024年 | 479篇 |
2023年 | 1869篇 |
2022年 | 4569篇 |
2021年 | 5749篇 |
2020年 | 4582篇 |
2019年 | 3831篇 |
2018年 | 3861篇 |
2017年 | 3864篇 |
2016年 | 3575篇 |
2015年 | 5622篇 |
2014年 | 7122篇 |
2013年 | 7013篇 |
2012年 | 10339篇 |
2011年 | 11081篇 |
2010年 | 7781篇 |
2009年 | 6535篇 |
2008年 | 7902篇 |
2007年 | 7666篇 |
2006年 | 7266篇 |
2005年 | 6656篇 |
2004年 | 5093篇 |
2003年 | 5341篇 |
2002年 | 4415篇 |
2001年 | 3533篇 |
2000年 | 2896篇 |
1999年 | 2493篇 |
1998年 | 1457篇 |
1997年 | 1427篇 |
1996年 | 1024篇 |
1995年 | 912篇 |
1994年 | 910篇 |
1993年 | 531篇 |
1992年 | 677篇 |
1991年 | 536篇 |
1990年 | 486篇 |
1989年 | 398篇 |
1988年 | 364篇 |
1987年 | 302篇 |
1986年 | 244篇 |
1985年 | 197篇 |
1984年 | 108篇 |
1983年 | 64篇 |
1982年 | 56篇 |
1981年 | 47篇 |
1980年 | 19篇 |
1979年 | 46篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1964年 | 7篇 |
1936年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
脊柱侧弯是青少年的多发病,发病率约1%,不但影响美观,也给患者心理健康造成危害,而且严重影响患者的心肺功能,甚至导致截瘫,目前最好的治疗方法是早期手术. 相似文献
32.
可切除原发性十二指肠恶性肿瘤X线征象分析 总被引:2,自引:0,他引:2
目的 :对可切除的原发性十二指肠恶性肿瘤X线征象进行分析。方法 :对 2 6例原发性十二指肠恶性肿瘤胃肠道造影及CT征象进行了回顾性对比分析总结。结果 :全部病例均经手术病理证实 ,其中腺癌 2 2例 ,平滑肌肉瘤 3例 ,非何杰金氏淋巴瘤 1例。描述包括肿瘤的部位 ,造影X线表现 (黏膜破坏 ,充盈缺损及龛影 ,管腔不规则狭窄 ,肠腔外改变等 )及CT表现 (肠壁增厚肠腔狭窄 ,局部肿块 ,梗阻性改变及转移 )。不能手术切除的影像学征象为 :肿瘤直径大于 6cm ;腹腔、系膜淋巴结成团肿大 ;腔静脉、肠系膜动静脉等重要血管管径被包绕大于 2 / 3时。结论 :CT与X线造影对肿瘤的位置、大小、形态 ,肿瘤的继发征象的术前评价 ,能够提供能否手术切除的重要依据。 相似文献
33.
C Y Chai A M Lin C K Su S R Hu C Yuan L S Kao J S Kuo D S Goldstein 《Journal of the autonomic nervous system》1991,33(1):35-46
Effects of stimulation of brainstem sites on hemodynamics and plasma catecholamine levels were assessed in cats under chloralose-urethane anesthesia. Pressor areas of the dorsal medulla (DM) and ventrolateral medulla (VLM) and the depressor area of the paramedian reticular nucleus (PRN) were stimulated electrically using a monopolar electrode, or chemically using sodium glutamate microinjection. Plasma levels of norepinephrine (NE) and epinephrine (EPI) were measured in caval blood above the adrenal veins. Electrical stimulation of the DM and VLM produced increases in blood pressure and in plasma NE and EPI levels that were enhanced after acute vagotomies. The NE and EPI responses were attenuated after acute, bilateral adrenalectomies, confirming augmented adrenomedullary secretion, whereas the pressor responses were intact. Injection of sodium glutamate into the same pressor regions of the DM or VLM also produced pressor responses and elevated plasma catecholamine levels, indicating that the responses resulted from activation of neuronal perikarya. Stimulation of the PRN attenuated pressor and catecholamine responses during stimulation of the DM and VLM. The results indicate that pressor responses during stimulation of the DM and VLM are due at least partly to activation of perikarya in these regions, are associated with but not dependent on adrenomedullary activation, and are enhanced after vagotomy; and that neurons of the PRN exert inhibitory modulation of the pressor and adrenomedullary responses during stimulation of VLM and DM. 相似文献
34.
A slow-moving gamma chain variant was discovered in the cord blood of an infant born to parents of the Han nationality from Jiangsu. The variant, which migrated electrophoretically at alkaline pH between Hb A and Hb D, was characterized by an Asp----His substitution at gamma 73, while residues gamma 75 and gamma 136 were occupied by Ile and Ala, respectively. As the A gamma T-chain was also present, this baby has two types of abnormal gamma-chain. The variant was named Hb F-Xin-Su. 相似文献
35.
持续压力超负荷对兔左心室细胞凋亡的影响 总被引:3,自引:1,他引:2
OBJECTIVE: To study the effect of chronic pressure overload on the apoptosis of the left ventricle myocytes in rabbits. METHODS: Rabbit models of chronic pressure overload-induced heart failure were prepared in which dynamic changes of apoptotic myocytes in the left ventricle were observed by way of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. RESULTS: Only a few apoptotic cells was observed in the sham-operated group, while in the experimental group, the apoptotic left ventricle myocytes significantly increased after operation, presenting a peak level between day 3 and day 7. Seven days after the operation, the apoptotic myocytes began to decrease and till day 14, the apoptotic cell number had been smaller than that measured on day 1. When signs of heart failure set in, the apoptotic myocytes were again increased (P<0.001). CONCLUSION: During chronic pressure overload, myocyte apoptosis in the left ventricle is elevated at the early stages and undulates subsequently, with the peak occurring before hypertrophy is obvious. 相似文献
36.
F Nakhoul L H Kayne N Brautbar M S Hu A McDonough P Eggena M S Golub M Berger C T Chang N Jamgotchian 《Toxicology and industrial health》1992,8(1-2):89-102
Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension. 相似文献
37.
为探索天然超氧化物岐化酶(SOD)岐化超氧离子的机理,及用于临床的可能性,我们合成了乳酸、柠檬酸和酒石酸的锰(Ⅱ)配合物作为Mn-SOD的模拟物,用光照法测定了它们的活性,得到了有意义的结果:锰配合物作为Mn-SOD的模拟物,有肯定的活性,其中以乳酸锰配合物活性最高。 相似文献
38.
P C Hu 《中华结核和呼吸杂志》1992,15(3):163-4, 191-2
In our study, we observed that (1) High RCIA were discovered in these two groups. (2) In the group of pulmonary tuberculosis, the C3b receptor activities remained no change after antituberculous therapy, but the amounts of immune complexes bearing on RBC decreased. In the patients with the high RCIA, CIC was discharged rapidly and the lesions of tissue produced by CIC were prevented. In the patients with silicotuberculosis, both silica and tuberculous bacilli may act as immune adjuvant and enhance the hypersensitivity. So the C3b receptor activities were higher in silicotuberculosis patients. 相似文献
39.
胃肠道肿瘤病人围手术期细胞因子及蛋白质代谢的变化 总被引:4,自引:0,他引:4
目的 :探讨胃肠道肿瘤病人手术后肿瘤坏死因子 α (TNF α)、白介素 6 (IL 6 )、白介素 10 (IL 10 )的变化以及与蛋白质代谢的关系。 方法 :用酶联免疫法 (ELISA)检测 19例胃肠道肿瘤根治术病人术前和术后 1、3、5天血清TNF α、IL 6和IL 10水平 ,同时检测蛋白质分解代谢相关指标、2 4h尿中尿素和肌酐排泄量。 结果 :胃肠道肿瘤根治术后病人TNF α呈下降趋势 ,术后第 1天较术前明显下降 (P <0 .0 5 )。IL 6和IL 10术后升高 (P <0 .0 1) ,尤以术后第 1天升高明显。术后 2 4h尿中尿素和肌酐排泄量明显升高。 结论 :胃肠道肿瘤根治术后病人IL 6和IL 10的升高支持手术应激导致的细胞因子释放变化 ,但TNF α呈下降趋势 ,可能与胃肠道肿瘤病人术前TNF α的高表达有关。术后蛋白质分解代谢增加 ,可能与细胞因子IL 6和IL 10的升高有关。 相似文献
40.