全文获取类型
收费全文 | 26506篇 |
免费 | 1813篇 |
国内免费 | 512篇 |
专业分类
耳鼻咽喉 | 776篇 |
儿科学 | 518篇 |
妇产科学 | 2458篇 |
基础医学 | 2916篇 |
口腔科学 | 1696篇 |
临床医学 | 2475篇 |
内科学 | 1658篇 |
皮肤病学 | 199篇 |
神经病学 | 2606篇 |
特种医学 | 908篇 |
外国民族医学 | 1篇 |
外科学 | 2637篇 |
综合类 | 3925篇 |
预防医学 | 1207篇 |
眼科学 | 354篇 |
药学 | 2159篇 |
9篇 | |
中国医学 | 772篇 |
肿瘤学 | 1557篇 |
出版年
2024年 | 19篇 |
2023年 | 328篇 |
2022年 | 546篇 |
2021年 | 943篇 |
2020年 | 825篇 |
2019年 | 800篇 |
2018年 | 804篇 |
2017年 | 811篇 |
2016年 | 846篇 |
2015年 | 918篇 |
2014年 | 1562篇 |
2013年 | 1659篇 |
2012年 | 1513篇 |
2011年 | 1629篇 |
2010年 | 1361篇 |
2009年 | 1308篇 |
2008年 | 1239篇 |
2007年 | 1239篇 |
2006年 | 1203篇 |
2005年 | 1023篇 |
2004年 | 901篇 |
2003年 | 716篇 |
2002年 | 589篇 |
2001年 | 560篇 |
2000年 | 511篇 |
1999年 | 426篇 |
1998年 | 385篇 |
1997年 | 354篇 |
1996年 | 341篇 |
1995年 | 347篇 |
1994年 | 351篇 |
1993年 | 261篇 |
1992年 | 242篇 |
1991年 | 219篇 |
1990年 | 204篇 |
1989年 | 169篇 |
1988年 | 185篇 |
1987年 | 155篇 |
1986年 | 152篇 |
1985年 | 224篇 |
1984年 | 171篇 |
1983年 | 119篇 |
1982年 | 155篇 |
1981年 | 132篇 |
1980年 | 97篇 |
1979年 | 73篇 |
1978年 | 82篇 |
1977年 | 41篇 |
1976年 | 28篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
无排卵性功能失调性子宫出血患者子宫内膜雌、孕激素受体及基质金属蛋白酶表达变化的研究 总被引:5,自引:0,他引:5
目的研究无排卵性功能失调性子宫出血(功血)患者子宫内膜雌激素受体(ER)、孕激素受体(PR)、IV型胶原、基质金属蛋白酶-9(MMP-9)及其抑制物-1(TIMP-1)的表达,探讨无排卵性功血的发病机制。方法采用免疫组化法检测20例正常增殖期子宫内膜(对照组)和66例无排卵性功血患者(病例组)子宫内膜腺上皮和基质细胞ER、PR、IV型胶原、MMP-9及TIMP-1表达。结果病例组子宫内膜腺上皮和基质ER、PR表达高于对照组(P<0.05),MMP-9水平明显增加(P<0.05),MMP-9/TIMP-1比值升高(P<0.01),IV型胶原含量明显下降(P<0.01)。相关分析显示,无排卵性功血患者子宫内膜MMP-9水平与ER、PR均呈正相关(r=0.605,P<0.05;r=0.697,P<0.05)。结论无排卵性功血患者子宫内膜出血原因可能与雌激素作用下ER、PR表达失调有关,且MMP-9水平异常升高,导致细胞外基质过度降解,临床表现为子宫不规则出血。 相似文献
82.
非控制性出血休克大鼠早期低压液体复苏的理想复苏压力研究 总被引:4,自引:1,他引:3
目的利用大鼠非控制性出血休克模型,探讨早期低压复苏的理想复苏压力。方法W istar大鼠64只,基础平均动脉血压(MAP)为(129.9±14.3)mmHg,断脾法复制非控制性出血休克模型,将血压(MAP)降至40或50mmHg,分为3个处理时段,第1时段模拟院前救治时段,用2∶1乳酸林格氏液和6%的右旋糖酐输注分别将MAP维持在40、50、60、70、80、100mmHg,维持1小时;第2时段模拟医院确定性处理情况,结扎脾动脉止血,输血输液将MAP恢复至100mmHg,维持2小时;第3时段,观察第1时段不同压力复苏对大鼠休克复苏效果的影响。观察指标包括动物存活情况、血压、液体输注量、血细胞比容及动脉血气等。结果院前急救采用高压复苏(80、100mmHg),动物存活时间短,在第1时段末就有50%的动物死亡,需要的液体输注量大,血液稀释严重,代谢性酸中毒明显,血气指标差;而以<70mmHg(50、60、70mmHg)的血压复苏,动物存活时间延长,液体输注量小,血液稀释轻,血气指标正常或接近正常;以50、60mmHg血压输注效果最好,但太低的输注压力(40mmHg)也不利于休克复苏,在第三时段末动物死亡率为75%。结论对非控制性出血休克及活动性出血,止血前采用高压复苏会增加血液丢失及血液稀释,明显影响休克复苏效果,适当低压复苏有利于动物的后期恢复,输注压力以50、60mmHg最好,但太低的输注压力(40mmHg)也不利于休克复苏。 相似文献
83.
冰片开放血-脑脊液屏障对实验性细菌性脑膜炎治疗影响的研究 总被引:2,自引:0,他引:2
目的 探讨冰片开放血-脑脊液屏障(BCB)对实验性细菌性脑膜炎治疗的影响。方法 采用日本大耳白兔作为实验动物,随机分为对照组、冰片组和脑膜炎组。经枕大池注入肺炎球菌悬液建立脑膜炎模型,以冰片作为开放BCB的制剂。以连续静脉注射丙戊酸钠后不同时间点的脑脊液中丙戊酸钠浓度变化作为判断BCB通透性的指标;硝酸镧示踪法观察脑组织表现作为BCB通透性的形态指标。给予脑膜炎动物头孢吡肟或冰片+头孢吡肟治疗,记录动物存亡情况;取脑脊液(CSF)进行细胞计数及生化检查。取脑组织作常规病理染色,以观察冰片开放BCB对实验性细菌性脑膜炎治疗的影响。结果 给药后对照组CSF中丙戊酸钠浓度基本保持稳定,冰片组CSF中丙戊酸钠浓度于给药后0.5h时即高于对照组并逐渐上升,至6h时达高峰,然后开始下降,14h时浓度仍高于对照组。脑组织超微结构显示,对照组无硝酸镧颗粒通过BCB,脑膜炎组硝酸镧颗粒分布于毛细血管基底膜外,冰片组弥漫性分布于神经细胞间隙和轴突周围。给予头孢吡肟治疗后,脑膜炎+冰片组动物存活率(9/12,75%)明显高于脑膜炎组(6/18,66.7%)(P〈0.05),但两组间CSF细胞数及蛋白、葡萄糖水平差异无统计学意义。近皮层脑组织HE染色显示,脑膜炎组可见脑组织大量炎症细胞渗出和软化坏死灶,血管“套袖”现象明显,而脑膜炎+冰片组脑组织内炎症细胞渗出较少,无血管“套袖”现象,无明显坏死软化灶。结论 冰片确实能明显增加BCB的通透性并具有可逆性特点,抗生素联合冰片能改善实验性细菌性脑膜炎治疗效果,为细菌性脑膜炎的治疗提供了新的思路。 相似文献
84.
A. Hedberg H-G. Hårdemark B. Olsson-Liljequist J. Sjölin 《Clinical microbiology and infection》2004,10(8):765-768
Cerebrospinal fluid (CSF) concentration-time curves of rifampicin and fusidic acid were studied in a patient with post-operative meningitis caused by Staphylococcus epidermidis. The patient was treated with this combination of antimicrobial agents because of a severe hypersensitivity reaction to vancomycin. Peak CSF concentrations of rifampicin exceeded the MIC by > 60-fold, while those of fusidic acid just reached the MIC. CSF concentrations of fusidic acid were relatively stable within the range reported for patients with uninflamed meninges, but serum levels were surprisingly low. An increase in the metabolism of fusidic acid induced by rifampicin cannot be excluded. 相似文献
85.
微波子宫内膜去除术治疗异常子宫出血34例疗效观察 总被引:1,自引:0,他引:1
目的探讨微波子宫内膜去除术(microwave endometrial ablation,MEA)治疗异常子宫出血的疗效及安全性。方法采用微波子宫内膜去除术治疗异常子宫出血患者34例,其中功能失调性子宫出血18例,子宫肌瘤16例。结果34例患者术后完成随访3-24个月,闭经19例(55.88%),明显改善7例(20.59%),改善7例(20.59%),月经未改善1例(2.94%),术后随访3月月经过多症状消失,治疗有效率达100%;随访2年后仍达93.3%。结论微波子宫内膜去除术是一种新的治疗异常子宫出血的方法,简便、快速、安全,并发症少。避免了宫腔镜子宫内膜电切术的液体灌注、手术中出血以及子宫穿孔的危险,并取得与之相似甚至更好的疗效。 相似文献
86.
Leo Sher Juan J Carballo Michael F Grunebaum Ainsley K Burke Gil Zalsman Yung-yu Huang J John Mann Maria A Oquendo 《Bipolar disorders》2006,8(5P2):543-550
Objectives: Bipolar disorder is a severe illness that is associated with suicidal behavior. A biological predictor of highly lethal suicide attempts in patients with bipolar disorder would be valuable. We hypothesized that cerebrospinal fluid (CSF) monoamine metabolite levels are related to lethality of suicide attempts in bipolar patients and examined the relation between CSF 5-hydroxyindolacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) levels and maximum lethality of suicide attempts at baseline and during a 2-year follow up.
Methods: Twenty-seven bipolar depressed patients participated in the study. Demographic and clinical parameters were examined and recorded. Lumbar punctures were performed and CSF 5-HIAA, HVA, and MHPG were assayed by high-performance liquid chromatography with electrochemical detection. Following discharge, patients were evaluated after 3 months, 1 year, and 2 years. Each follow-up interview included an in-depth assessment of suicidal behavior during the intervening time period.
Results: Six subjects made suicide attempts during the 2-year follow-up. Bipolar patients who attempted suicide during the follow-up period had higher aggression and hostility scale scores compared to bipolar subjects who did not make a suicide attempt during the follow-up period. CSF 5-HIAA, HVA, and MHPG levels were negatively correlated with the maximum lethality of suicide attempts during the 2-year follow-up period.
Conclusions: Our finding is the first observation that CSF monoamine metabolite levels may be predictors of lethality of suicide attempts in patients with bipolar disorder. Further studies are necessary to answer the question whether CSF monoamine metabolite levels are clinically useful biochemical predictors of highly lethal suicide attempts or completed suicides. 相似文献
Methods: Twenty-seven bipolar depressed patients participated in the study. Demographic and clinical parameters were examined and recorded. Lumbar punctures were performed and CSF 5-HIAA, HVA, and MHPG were assayed by high-performance liquid chromatography with electrochemical detection. Following discharge, patients were evaluated after 3 months, 1 year, and 2 years. Each follow-up interview included an in-depth assessment of suicidal behavior during the intervening time period.
Results: Six subjects made suicide attempts during the 2-year follow-up. Bipolar patients who attempted suicide during the follow-up period had higher aggression and hostility scale scores compared to bipolar subjects who did not make a suicide attempt during the follow-up period. CSF 5-HIAA, HVA, and MHPG levels were negatively correlated with the maximum lethality of suicide attempts during the 2-year follow-up period.
Conclusions: Our finding is the first observation that CSF monoamine metabolite levels may be predictors of lethality of suicide attempts in patients with bipolar disorder. Further studies are necessary to answer the question whether CSF monoamine metabolite levels are clinically useful biochemical predictors of highly lethal suicide attempts or completed suicides. 相似文献
87.
通过对国产硫酸奈替米星注射后人体血尿中药物浓度测定,建立了奈替米星体液浓度测定的微生物法,该方法的检测限为0.0375~0.0751μg,最低检测浓度为0.25~0.5μg/ml,回收率为88.8%±3.63%~98%±14.40%,重复性试验相对标准差为2.22%~5.34%;并对10例健康受试者用药后血标本100余份进行了微生物法测定和高压液相色谱法测定,对两种方法测定结果的比较发现:微生物法测定的血药浓度明显高于HPLC法(P<0.01),而HPLC法由于需复杂的样品预处理和特殊的色谱条件,测定的血药浓度较低,回收率仅71.98%~76.96%。不过,两种方法测定结果的相关性较好。本研究结果提示:微生物法测定奈替米星体液浓度简便、易操作、结果准确可信,适用于体液药物浓度测定。 相似文献
88.
Chromosomes in 1620 metaphases of ascitic fluid cells in 20 cases of ovariancarcinoma were analyzed.The results showed that there were marked structuralaberrations aside from significant increase in chromosomal numerical aberrations(85.2%).In the ascitic fluid cells from 12 patients,15 types of marker chromosomes were found,among which t(6;14)(q21;q24)and t(2;6)(q35;p12)were more frequently noted witha rate of 7.84% and 7.59% respectively,which was significantly higher than that of othermarker chromosomes(P<0.01).The findings suggested that,besides t(6;14)(q21;q24),t(2;6)(q35;p12)may also be a specific marker chromosome of ovarian carcinoma. 相似文献
89.
90.