全文获取类型
收费全文 | 20441篇 |
免费 | 1654篇 |
国内免费 | 658篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 216篇 |
妇产科学 | 140篇 |
基础医学 | 839篇 |
口腔科学 | 139篇 |
临床医学 | 1486篇 |
内科学 | 2546篇 |
皮肤病学 | 276篇 |
神经病学 | 1876篇 |
特种医学 | 199篇 |
外国民族医学 | 1篇 |
外科学 | 748篇 |
综合类 | 2236篇 |
一般理论 | 3篇 |
预防医学 | 1173篇 |
眼科学 | 155篇 |
药学 | 8726篇 |
7篇 | |
中国医学 | 1264篇 |
肿瘤学 | 684篇 |
出版年
2024年 | 60篇 |
2023年 | 325篇 |
2022年 | 479篇 |
2021年 | 691篇 |
2020年 | 685篇 |
2019年 | 758篇 |
2018年 | 767篇 |
2017年 | 826篇 |
2016年 | 724篇 |
2015年 | 721篇 |
2014年 | 1448篇 |
2013年 | 2205篇 |
2012年 | 1308篇 |
2011年 | 1375篇 |
2010年 | 1104篇 |
2009年 | 906篇 |
2008年 | 853篇 |
2007年 | 883篇 |
2006年 | 730篇 |
2005年 | 655篇 |
2004年 | 544篇 |
2003年 | 532篇 |
2002年 | 378篇 |
2001年 | 363篇 |
2000年 | 282篇 |
1999年 | 240篇 |
1998年 | 223篇 |
1997年 | 215篇 |
1996年 | 212篇 |
1995年 | 187篇 |
1994年 | 155篇 |
1993年 | 187篇 |
1992年 | 182篇 |
1991年 | 137篇 |
1990年 | 131篇 |
1989年 | 106篇 |
1988年 | 116篇 |
1987年 | 75篇 |
1986年 | 87篇 |
1985年 | 127篇 |
1984年 | 113篇 |
1983年 | 82篇 |
1982年 | 92篇 |
1981年 | 61篇 |
1980年 | 70篇 |
1979年 | 55篇 |
1978年 | 63篇 |
1977年 | 56篇 |
1976年 | 47篇 |
1975年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
121.
Two techniques for measuring palmar sweating were tested for their sensitivity to a standard anticholinergic agent. The finger sweat-print and palmar sweatweight methods were compared in a double-blind, crossover study by determining their relative sensitivity in detecting the antisweating effects of 0.5 mg of atropine sulfate. The sweat-print method was significantly superior in detecting drug-induced sweat reduction and hypothesized sex differences. 相似文献
122.
There are a number of reports suggesting an association between profusion of eye movements and active dreaming. It has however been suggested that this relationship might only be evident in comparisons across the night and would not be evident in comparisons within one REM period. Data from 20 subjects taking placebo, amylobarbitone, and nitrazepam were used to test this. Dream reports were collected from REM awakenings and rated blind as visually active or passive. Eye movement profusion (number of 2 sec epochs) was assessed for each REM period. Correlation between dream content and eye movement was low but significant in comparisons including the whole night, and including data from drug, withdrawal, and placebo conditions. A significant correlation was not consistently obtained, however, when data from each REMP were considered separately. Correlations based on data from non-drug nights only were also small and could have been due to chance effects alone. The low correlations were not explicable solely by poor reliability of content ratings. It is concluded that the relationship between visually active dreaming and eye movement is slight, and may not hold when time of night is adequately controlled. 相似文献
123.
目的探讨妊娠合并癫痫临床处理。方法回顾性分析16例妊娠合并癫痫孕妇服抗癫痫药情况、癫痫发作频率变化及妊娠结局。结果妊娠合并癫痫发生率0.078%,原发性4例,继发性12例。全身性癫痫发作13例(2例癫痫持续状态),局部癫痫发作3例。孕期发作频率增加者5例,无变化者6例。孕期新发现单次发作5例。孕期未用抗癫痫药物(AEDs)3例,间断用药1例,连续用药7例,均为单一AEDs治疗。顺产4例,剖宫产10例,人工流产2例。新生儿出生无窒息,平均出生体重2852g,无新生儿出生缺陷,无新生儿死亡。母亲亦无产科并发症发生。2例人工流产孕妇癫痫持续状态、吸入性肺炎死亡,1例智力低下孕妇产后卡马西平中毒昏迷,抢救成功。结论妊娠可诱发并使癫痫发作频率增加。孕期用AEDs可控制癫痫发作。应采用单一AEDs治疗,且应按时监测血浆中AED及叶酸水平。 相似文献
124.
125.
目的探讨基质金属蛋白酶-2/基质金属蛋白酶-2特异性组织抑制因子(MMP-2/TI MP-2)在脱氧皮质酮(DOCA)-盐型高血压大鼠(DHR)心脏微小血管重塑中的作用及其可能的调节机制。方法30只雄性SD大鼠,等分和制作为对照组、模型组、波生坦组、氨氯地平组和雷米普利组。5周末处死动物,检测心脏微小血管密度和MMP-2/TI MP-2蛋白与基因的表达。结果在DHR左心室心内膜下心肌中存在微小动脉密度增加和毛细血管密度减少,MMP-2的mRNA和MMP-2/TI MP-2的蛋白表达上调;波生坦和氨氯地平能明显减轻微小血管损害,下调MMP-2/TI MP-2的mRNA和蛋白表达;雷米普利不能减轻微小血管损害,也不影响MMP-2/TI MP-2的mRNA和蛋白表达;MMP-2的表达同微小血管密度间具有良好的相关性。结论在DHR心脏中存在微小血管病变,MMP-2/TI MP-2表达可能参与微小血管病变的病理机制,内皮素-1和血压可能是通过调节MMP-2/TI MP-2表达参与微小血管病变。 相似文献
126.
127.
128.
G L Sussman R P Harvey A L Schocket 《The Journal of allergy and clinical immunology》1982,70(5):337-342
Delayed pressure urticaria (DPU) is a poorly understood syndrome. We describe 17 patients with DPU. Chronic urticaria was present in 94%. All had negative challenges for immediate demographism and cold urticaria. DPU was induced with a pressure challenge on the shoulder of 15 pounds for 15 min. Average onset of pressure lesions after challenge was 6.5. Lesions were painful, not pruritic, peaked at 9 hr, and disappeared by 24 to 48 hr. Fever, chills, and/or arthralgias occurred in 78%. Positive laboratory abnormalities included leukocytosis in 20% and elevated erythrocyte sedimentation rate in 37.5%. Skin biopsies of lesions showed perivascular round cell infiltrates and negative immunofluorescence. Urticaria responded to antihistamines, but not aspirin, in 100% of patients, while pressure lesions improved with nonsteroidal anti-inflammatory drugs (NSAID), but not antihistamines, in 80% of patients. Both urticaria and DPU were controlled with prednisone, which was necessary in 87.5% of patients. A severe nonremitting course was noted in 7%, 40% had a moderate remitting course requiring intermittent prednisone, and 53% had a mild remitting disease requiring no medication or antihistamines and/or NSAID only. We conclude that DPU is more common than previously appreciated and likely involves mediators other than histamine, possibly the prostaglandin system. 相似文献
129.
Fifteen percutaneous renal biopsies from patients with acute renal failure due to acute interstitial nephritis (AIN), in almost all cases due to drugs, were studied by electron microscopy. Differential counting of interstitial cells showed an average of 69% lymphocytes (small and large) and 11 % macrophages. Plasma cells and eosinophils were comparatively rare. The infiltrate resembled that of acute rejection, suggesting a cellular hypersensitivity reaction. Proximal and distal tubules were severely affected focally. Migration of lymphocytes through the tubular basement membrane of otherwise well-preserved tubules was considered to be the first phase. Other tubules showed extreme thinning of the tubular basement membrane, with still intact cellular walls. Rupture of the tubular basement membrane and necrotic disintegration of tubular epithelial cells are probably late phenomena. The non-necrotic tubules displayed severe reduction of proximal brush border and proximal as well as distal tubular basolateral infoldings. Focal tubular disintegration leading to tubular block and/or backleak as well as decrease of proximal tubular sodium resorption leading to a decreased glomerular filtration (a mechanism probably also acting in ischemic acute renal failure) may all be factors responsible for the acute renal failure in AIN. 相似文献
130.
Ro 11-2465 (cianopramine, cyan-imipramine) and citalopram (CIT), putative antidepressant drugs, are very potent and selective 5-hydroxytryptamine (5-HT) uptake inhibitors in vitro. This study investigated the effects of these drugs and their desmethyl metabolites, Ro 12-5419 (desmethylcianopramine, cyan-desipramine) and desmethylcitalopram (DCIT), respectively, on the uptake of 5-HT and noradrenaline (NA) in vivo [protection against H 77/77 (4, alpha-dimethyl-metatyramine)-induced displacement of 5-HT and NA] and on related pharmacological activities. All the investigated drugs antagonized H 77/77-induced displacement of 5-HT in the rat brain, though the effects of the metabolites were considerably weaker than those of the parent compounds. The H 77/77-induced displacement of brain NA in rats and mice was antagonized only by Ro 12-5419 and Ro 11-2465. All the drugs potentiated the pressor response to 5-HT in pithed rats; however, Ro 12-5419 and particularly Ro 11-2465 could also block the response when used in higher doses (0.1 mg/kg). Only Ro 12-5419 and Ro 11-2465 were able to potentiate the pressor response to NA. Ro 12-5419 also potentiated thyrotropin releasing hormone (TRH) hyperthermia and antagonized reserpine hypothermia in mice; Ro 11-2465 potentiated the TRH hyperthermia only. CIT and DCIT were inactive in both these tests. Of all the four drugs only CIT and Ro 12-5419 considerably stimulated the hind limb flexor reflex in spinal rats. However, whereas the stimulatory effect of CIT was inhibited by the 5-HT antagonists metergoline and cyproheptadine, that of Ro 12-5419 was counteracted by the NA antagonist phenoxybenzamine only. Ro 11-2465, when used in low doses (ca. 1 mg/kg), slightly potentiated the flexor reflex, whereas in higher doses (4–16 mg/kg) it had no effect itself but antagonized the stimulatory action of the 5-HT agonists fenfluramine, quipazine and LSD. The results obtained indicate that Ro 11-2465 and CIT, as well as their desmethyl metabolites, are also potent 5-HT uptake inhibitors in vivo. However, only CIT and DCIT are concurrently devoid of effect on uptake of NA. In contrast, Ro 11-2465 and particularly Ro 12-5419 appear to also inhibit the uptake of NA. Moreover, Ro 11-2465 appears to block central and peripheral 5-HT receptors.The results were presented at the 14th CINP Congress, Florence, June 19–23, 1984 相似文献