全文获取类型
收费全文 | 21650篇 |
免费 | 3109篇 |
国内免费 | 1167篇 |
专业分类
耳鼻咽喉 | 159篇 |
儿科学 | 373篇 |
妇产科学 | 203篇 |
基础医学 | 2046篇 |
口腔科学 | 440篇 |
临床医学 | 2839篇 |
内科学 | 2790篇 |
皮肤病学 | 382篇 |
神经病学 | 980篇 |
特种医学 | 666篇 |
外国民族医学 | 3篇 |
外科学 | 1859篇 |
综合类 | 4323篇 |
现状与发展 | 9篇 |
一般理论 | 5篇 |
预防医学 | 2012篇 |
眼科学 | 612篇 |
药学 | 2761篇 |
30篇 | |
中国医学 | 1916篇 |
肿瘤学 | 1518篇 |
出版年
2024年 | 154篇 |
2023年 | 537篇 |
2022年 | 1293篇 |
2021年 | 1610篇 |
2020年 | 1348篇 |
2019年 | 1008篇 |
2018年 | 1007篇 |
2017年 | 1048篇 |
2016年 | 837篇 |
2015年 | 1217篇 |
2014年 | 1359篇 |
2013年 | 1468篇 |
2012年 | 1844篇 |
2011年 | 1808篇 |
2010年 | 1428篇 |
2009年 | 1126篇 |
2008年 | 1189篇 |
2007年 | 1022篇 |
2006年 | 836篇 |
2005年 | 687篇 |
2004年 | 467篇 |
2003年 | 409篇 |
2002年 | 376篇 |
2001年 | 313篇 |
2000年 | 224篇 |
1999年 | 158篇 |
1998年 | 102篇 |
1997年 | 86篇 |
1996年 | 72篇 |
1995年 | 62篇 |
1994年 | 52篇 |
1993年 | 57篇 |
1992年 | 61篇 |
1991年 | 36篇 |
1990年 | 47篇 |
1989年 | 63篇 |
1988年 | 41篇 |
1987年 | 40篇 |
1986年 | 37篇 |
1985年 | 28篇 |
1984年 | 33篇 |
1983年 | 27篇 |
1982年 | 20篇 |
1981年 | 17篇 |
1980年 | 18篇 |
1977年 | 17篇 |
1976年 | 15篇 |
1975年 | 18篇 |
1974年 | 14篇 |
1972年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
目的:观察玉屏风散颗粒治疗慢性阻塞性肺病的临床疗效和提高免疫功能的作用。方法:采用随机对照开放试验方法。以多抗甲素为阳性对照,观察了玉屏风散颗粒治疗慢性阻塞性肺病33例的临床疗效。结果:玉屏风散颗粒治疗组和多抗甲素对照组对慢性阻塞性肺病患者显效率分别为63.64%、68.97%,总有效率分别为96.97%、96.56%(均P>0.05)。治疗后症状评分平均下降分别为9.52±4.19、10.21±4.25(P>0.05)。两组临床疗效相当。玉屏风散颗粒能显著提高血清IgG(13.17g/L±3.26g/L上升至14.22g/L±3.12g/L)、IgM(1.41g/L±0.54g/L上升至1.64g/L±0.70g/L)、C3(0.80±0.21上升至0.89±0.22)含量,P<0.05,提示其提高体液免疫功能显著优于多抗甲素。结论:玉屏风散颗粒对慢阻肺患者的疗效与多抗甲素相当。在提高免疫指标方面明显优于多抗甲素。 相似文献
143.
Hsieh BT Hsieh JF Tsai SC Lin WY Huang HT Ting G Wang SJ 《Nuclear medicine and biology》1999,26(8):741-972
Balloon angioplasty is a standard treatment for artherosclerotic coronary artery disease. However, its clinical value is reduced by a high restenosis rate. A new concept in preventing restenosis is the use of a liquid-filled balloon containing a beta-emitting radioisotope. In this study, we performed biodistribution studies of Re-188 perrhenate and Re-188 diethylenetriaminopentaacetate (DTPA) to assess the resulting organ dose values in the event of balloon rupture if these agents are used for the clinical inhibition of restenosis after percutaneous transluminal coronary angioplasty (PTCA). After injecting Re-188 preparations intravenously, rats were killed at 10 min, 30 min, 60 min, 2 h, and 6 h ( n =5 per group). Tissue concentrations were calculated and expressed as percent injected dose per gram or per milliliter (%ID/g or %ID/mL). In addition, urine excretion and thyroid gland uptake were evaluated in rats ( n=5 per group) with a gamma camera after administration of 37 MBq (1 mCi) of each agent. Our data showed that both agents were excreted primarily via urine. However, the excretion of Re-188 DTPA was much faster than that of Re-188 perrhenate via the urinary system. The biodistribution data revealed that radioactivity levels in the stomach and the thyroid gland were high in the perrhenate group but low in the Re-188 DTPA group. The concentration levels in other tissues including lung, liver, testis, muscle, and blood were low throughout this study for both agents. The thyroid radiation value in the Re-188 perrhenate group was 0.163 mGy/MBq, which was much higher than that of the Re-188 DTPA group (0.0167 mGy/MBq). The stomach radiation value was as high as 0.127 mGy/MBq for Re-188 perrhenate, compared with 0.013 mGy/MBq for Re-188 DTPA. In conclusion, in the event of balloon rupture, the release of Re-188 DTPA results in lower radiation doses than Re-188 perrhenate, especially to the thyroid gland and the stomach. Our data suggest that Re-188 DTPA is a useful radiopharmaceutical for endovascular irradiation. 相似文献
144.
Detry O Arkadopoulos N Ting P Kahaku E Margulies J Arnaout W Colquhoun SD Rozga J Demetriou AA 《Transplantation》1999,67(5):767-770
During orthotopic liver transplantation (OLT) for fulminant hepatic failure (FHF), some patients develop cerebral injury secondary to intracranial hypertension. We monitored intracranial pressure (ICP) and cerebral perfusion pressure (CPP) before and during OLT in 12 FHF patients undergoing transplantation. All four patients who had normal ICP preoperatively maintained normal ICP/CPP throughout OLT. During OLT, four of the eight patients with pretransplant intracranial hypertension had six episodes of ICP increase. These episodes of intracranial hypertension occurred during failing liver dissection (n=3) and graft reperfusion (n=3). At the end of the anhepatic phase, the ICP was lower than the preoperative ICP in all patients, and was below 15 mmHg in all but one patient. These data suggest that in FHF patients who develop intracranial hypertension before OLT, dissection of the native liver and graft reperfusion are associated with a risk of brain injury resulting from intracranial hypertension and cerebral hypoperfusion. 相似文献
145.
Ahmed E. Ahmed Ting F. Hsu Rokea A. el-Azhary Helmy Moawad Herbert H. Farrish Jr. John Costanzi 《Cancer chemotherapy and pharmacology》1982,8(3):271-276
Summary The kinetics of uptake and elimination, covalent binding, and macromolecular interactions of 14[C-ring] melphalan was studied after a single oral dose (20 mg/kg, 0.1 mCi/kg) in normal rats. Peak radioactivity level in tissues was observed at 2–4 h after administration. Uptake of label in most tissues was rapid, with a t1/2 of less than 1 h. Elimination was biphasic. Tissues of the gastrointestinal tract showed the most rapid rates of elimination, with t1/2 of 13, 24, 18, and 19 h for stomach, duodenum, and small and large intestines, respectively. Bone marrow also showed a fast rate of elimination of radioactivity, with a t1/2 of 30 h. Tissues with the slowest rates of elimination were skin, eye, spleen, pancreas, and lung, with t1/2 of 333, 241, 149, 122, and 109 h, respectively. Covalent binding studies showed that melphalan, or its metabolites, bound irreversibly to all tissue macromolecular fractions. The percentage of covalently bound radioactivity increased with time in all tissues except kidney and eye, reaching up to 70%–80% of the total radioactivity remaining at 72 h. Elimination of covalently bound radioactivity was slower in the DNA fractions of the tissues of the gastrointestinal tract and heart compared with the elimination rate from lipid, protein, or RNA fractions. Slow elimination rates of 14[C-ring] melphalan equivalents from the protein fraction were observed in the skin, eye, and brain. Accumulation, rather than elimination, of radioactivity in this fraction was most prominent in the pancreas. In the bone marrow accumulation of radioactivity was observed in the lipid fraction.Abbreviations used in this paper are L-Pam
Melphalan, l-phenylalanine mustard 4-bis (2-chloroethyl) amino-1-phenylalanine
-
l-DOH
4-bis (2-hydroxyethyl) amino-1-phenylalanine
-
l-MOH
4-2 hydroxyethyl 2 chloroethyl amino-1-phenylalanine
- HPLC
high-pressure liquid chromatography
- TCA
trichloroacetic acid
- AUC
area under the curve
- GIT
gastrointestinal tract 相似文献
146.
目的:探讨高压氧疗法(HBOT)对人重组骨形成蛋白-2(rhBMP-2)诱导骨形成的活性的影响。方法:I型胶原作为rhBMP-2的载体,将1mg的rhBMP-2植入Wistar鼠小腿的肌袋内,30只鼠被随机分成HBO组和对照组。在材料植入3,7,21d时对新骨形成分别进行X线、生化分析及组织学检查。结果:21d时两组中均有新骨形成,但HBO组新骨形成明显高于对照组。7d时在HBO组植入材料的周边有软骨组织出现;同时,在7d和21d时HBO组碱性磷酸酶(ALP)活性和钙(Ca)含量明显高于对照组。结论:HBO加快了人重组骨形成蛋白-2(rhBMP-2)诱导骨形成的活性和速度。 相似文献
147.
目的 :探讨 Snoreguard矫治器对阻塞性呼吸暂停综合征 ( OSAS)患者气道、睡眠结构的影响。方法 :选择 2 6岁~ 5 9岁患有 OSAS的患者 8例 ,在睡眠时分别配戴 Snoreguard矫治器 ,同时结合应用头颅侧位片、夜间多导睡眠图监测来测定分析配戴 Snoreguard矫治器的测量指标 ,进行统计分析。结果 :配戴 Snoreguard矫治器后 ,8例患者的AI值、平均呼吸暂停时间、AHI值均有显著性的降低 ( P<0 .0 1) ,Sa O2 显著增加 ( P<0 .0 1) ,HI值降低显著 ( P<0 .0 5 )。鼾声指数大幅度减轻甚至消失 ( P<0 .0 1)。配戴矫治器后下颌在水平向和垂直向的位移平均为 2 .0 3 mm和 8.74m m,IAS无显著变化 ,MAS变化明显 ( P<0 .0 5 ) ,最显著性改变的是上气道后间隙 ( SPAS) ( P<0 .0 1) ,SPL 减少 3 .64m m。结论 :Snoreguard矫治器是通过将下颌限制在一个前伸位 ,从而改变口咽部的结构影响上气道大小来达到治疗效果 相似文献
148.
轮状病毒致新生鼠胆管损伤的机制 总被引:4,自引:0,他引:4
目的 了解轮状病毒致新生鼠胆管损伤的分子机制。方法 实验共需成年雄性鼠13只,雌性鼠25只。将小鼠按每笼1只雄性与2只雌性的比例将动物分成13笼,饲养于层流室内,新生鼠出生后24-48h内将其随机分成5组,每组5窝,每窝5—8只。不同组腹腔内注射不同滴度的猴轮状病毒MMU18006,其中一组加用吡咯二硫氨基甲酯(PDTC),对照组腹腔注射相同剂量的病毒培养液。在注射病毒后5、10、15、2l及28d各处死一批动物,观察动物的体重变化及肝内外胆管的组织学改变。免疫组化法检测轮状病毒VP7抗原及NF-κB在肝内外胆管中的表达,并对NF-κB的表达进行原位杂交研究。结果 病毒注射组小鼠体重的增加明显侵于对照组。病毒注射后鼠肝胆系统出现急慢性炎症反应,且可见肝外胆管狭窄及胆道闭锁。病毒注射组均可检测到病毒抗原。病毒注射后NF-κB的表达在蛋白质水平与mRNA水平均增高,PDTC能抑制NF-κB的表达增高并可减轻炎症反应的程度。结论 NF-κB在介导轮状病毒对新生鼠肝内外胆管损伤中有重要作用,这种作用可被PDTC所抑制。 相似文献
149.
跌打活血涂膜剂质量控制研究 总被引:1,自引:0,他引:1
目的 :建立跌打活血涂膜剂质控方法。方法 :采用薄层鉴别法对跌打活血涂膜剂进行定性 ,并采用分光光度法在512nm波长处测定该药中大黄素的含量。结果 :平均回收率为101.2 % ,精密度为0.78 %。结论 :该方法重现性好 ,可作为本品的质量控制标准 相似文献
150.
目的:探讨溶出介质的离子强度对难溶性药物的丙基甲基纤维素(HPMC)骨架片释药的影响。方法:以甲氧苄胺嘧啶、卡马西平、磺胺甲恶唑和茶碱4种难溶性药物为模型药物,测定5种不同离子强度介质(水、0.20%氯化钠溶液、0.50%氯化钠溶液、0.90%氯化钠溶液和1.80%氯化钠溶液)下的药物释放度和溶出参数。结果:难溶性药物的HPMC骨架片释药随着其溶出介质离子强度的增加而减慢。结论:释药速率与离子强度之间存在较好的线性负相关关系。 相似文献