全文获取类型
收费全文 | 171021篇 |
免费 | 17339篇 |
国内免费 | 12094篇 |
专业分类
耳鼻咽喉 | 1341篇 |
儿科学 | 2517篇 |
妇产科学 | 1865篇 |
基础医学 | 17407篇 |
口腔科学 | 2899篇 |
临床医学 | 24557篇 |
内科学 | 21992篇 |
皮肤病学 | 1577篇 |
神经病学 | 8130篇 |
特种医学 | 5694篇 |
外国民族医学 | 72篇 |
外科学 | 13626篇 |
综合类 | 34166篇 |
现状与发展 | 44篇 |
一般理论 | 17篇 |
预防医学 | 14404篇 |
眼科学 | 4859篇 |
药学 | 19258篇 |
249篇 | |
中国医学 | 12980篇 |
肿瘤学 | 12800篇 |
出版年
2024年 | 685篇 |
2023年 | 2747篇 |
2022年 | 7344篇 |
2021年 | 9089篇 |
2020年 | 7211篇 |
2019年 | 5631篇 |
2018年 | 5804篇 |
2017年 | 5634篇 |
2016年 | 5217篇 |
2015年 | 7974篇 |
2014年 | 9934篇 |
2013年 | 9701篇 |
2012年 | 13920篇 |
2011年 | 15306篇 |
2010年 | 10593篇 |
2009年 | 8742篇 |
2008年 | 10280篇 |
2007年 | 9917篇 |
2006年 | 9516篇 |
2005年 | 8631篇 |
2004年 | 5553篇 |
2003年 | 5149篇 |
2002年 | 4215篇 |
2001年 | 3466篇 |
2000年 | 3244篇 |
1999年 | 2942篇 |
1998年 | 1835篇 |
1997年 | 1749篇 |
1996年 | 1418篇 |
1995年 | 1269篇 |
1994年 | 1105篇 |
1993年 | 687篇 |
1992年 | 702篇 |
1991年 | 609篇 |
1990年 | 558篇 |
1989年 | 499篇 |
1988年 | 414篇 |
1987年 | 346篇 |
1986年 | 266篇 |
1985年 | 210篇 |
1984年 | 99篇 |
1983年 | 55篇 |
1982年 | 49篇 |
1981年 | 49篇 |
1980年 | 28篇 |
1979年 | 25篇 |
1977年 | 6篇 |
1974年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
一种直接高效克隆PCR产物的载体制备 总被引:1,自引:0,他引:1
Bluescript经EcoR V酶切后,在Taq酶作用下加入dTTP使其3’端加上碱基“T”而成为3’端突出的粘性末端载体。用此载体直接与PCR产物连接进行克隆。克隆效率比采用平端载体克隆的效率提高约50倍。 相似文献
102.
103.
综合医院精神科会诊患者失眠的临床研究 总被引:3,自引:0,他引:3
目的:探讨综合医院精神科会诊患者失眠的临床特征及与其它精神障碍的关系。方法:对168例精神科会诊患者进行分析。结果:128例(76、2%)会诊患者有失眠.其中61.7%(79/128)为慢性失眠。原发性失眠仅占5.5%(7/128),85.1%(109/128)是与其它精神障碍有关的失眠。常见的精神障碍诊断为焦虑障碍、心境障碍和谵妄。60.9%的失眠患者在会诊前得到了处理。结论:应对临床医师进行精神卫生教育,提高他们对失眠等常见精神障碍的识别和处理能力。 相似文献
104.
Toshikazu Tanaka Peter C Amadio Chunfeng Zhao Mark E Zobitz Kai-Nan An 《Journal of orthopaedic research》2006,24(4):757-762
While attrition from sharp bony surfaces is the most common cause of extensor digiti minimi (EDM) tendon rupture, the etiology of other cases of spontaneous EDM tendon rupture is still unknown. Friction within the compartment may play a role, especially with ulna dislocation. The purpose of this study was to compare gliding resistance of the EDM tendon with that of a tendon which rarely ruptures spontaneously, the extensor digitorum communis of the middle finger (EDC III) tendon, under various wrist and ulna head positions. Eight fresh frozen cadavers were used. Gliding resistance between the tendon and its sheath in each compartment was measured in five different wrist positions and three different ulna head positions. Gliding resistance of the EDM tendon (0.13 +/- 0.03 N) was significantly greater than the EDC III tendon (0.09 +/- 0.03 N) (p < 0.05). For the EDM tendon, the gliding resistance in ulnar deviation or pronation was higher than the gliding resistance in neutral, radial deviation, or supination (p < 0.05), and the gliding resistance with ulnar lengthening (over 6 mm) or dorsal ulnar dislocation (over 9 mm) was higher than in neutral ulnar head positioning. For the EDC III tendon, the gliding resistance in ulnar deviation was significantly higher than the gliding resistance in neutral, radial deviation, or supination, or dorsal dislocation with ulnar lengthening (p < 0.05). Wrist ulnar deviation, ulnar dorsal dislocation (over 9 mm), and ulnar lengthening (over 6 mm) increased the gliding resistance of the EDM tendon. In patients at risk for EDM rupture, such as those with rheumatoid arthritis or distal radioulnar joint osteoarthritis, avoiding such positions may be advantageous. 相似文献
105.
Anatomic and spiral computed tomographic study of the genial tubercles for genioglossus advancement.
Shan Kai Yin Hong Liang Yi Wen Ying Lu Jian Guan Hong Min Wu Zhen Yu Cao Dong Zhen Yu Yan Yan Huang Chun Gen Wu 《Otolaryngology--head and neck surgery》2007,136(4):632-637
OBJECTIVE: To measure and compare Chinese mandibular genial tubercles measured anatomically and with computed tomography (CT). STUDY DESIGN AND SETTING: Spiral CT scans were taken of 40 adult human skulls; the superior genial spines were measured using anatomic and CT methods. RESULTS: The height and width of the superior genial spines, mandible thickness, and distance from the menton to the inferior and superior margins of the superior genial spines were 5.82 +/- 0.71, 6.98 +/- 1.35, 11.95 +/- 1.59, 11.08 +/- 2.05, and 16.91 +/- 2.30 mm from anatomic measurements and 6.17 +/- 0.71, 7.01 +/- 1.13, 12.19 +/- 1.64, 10.41 +/- 1.55, and 15.73 +/- 2.12 mm using spiral CT, respectively. The anatomic and CT measurements were correlated. CONCLUSION: Spiral CT of the genial tubercles can help locate the osteotomy in genioglossus advancement. SIGNIFICANCE: This study acquired reference data on Chinese genial tubercles demonstrating that CT measurements of the genial tubercles reflect their anatomy, which should allow accurately locate the osteotomy. 相似文献
106.
支气管哮喘是一种由多种细胞及细胞因子参与的慢性炎症性疾病。气道慢性炎症导致气道高反应,从而产生反复发作的喘息、胸闷、呼吸困难、咳嗽等相关症状,尤其多发于夜间及凌晨。我科自2005年6月开始采用特布他林、异丙托溴胺、布地奈德联合雾化吸入治疗老年哮喘急性发作取得满意疗效。现报告如下。1一般资料1.1对象我科2005年6月—2007年5月共收治老年支气管哮喘急性发作病人78例,年龄65岁~95岁(73.0岁±6.0岁),均符合诊断标准[1]。随机分为两组,对照组38例:男30例,女8例;治疗组40例:男35例,女5例。两组年龄、性别比较,差异无统计学意义(P>0… 相似文献
107.
108.
Anders Bergdahl Torun Nilsson Xiang Ying Sun Thomas Hedner Lars Edvinsson 《European journal of pharmacology》1998,360(2-3):165-173
The aim of the present study was to elucidate if the potentiating effect of neuropeptide Y on various vasoactive agents in vitro is (1) altered in mesenteric arteries from rats with congestive heart failure and (2) mediated by the neuropeptide Y Y1 receptor. The direct vascular effects of neuropeptide Y and its modulating effects on the contractions induced by endothelin-1-, noradrenaline-, 5-hydroxytryptamine (5-HT)-, U46619-(9, 11-dideoxy-11, 9-epoxymethano-prostaglandin F2) and ATP, and acetylcholine-induced dilatations were studied in the presence and absence of the neuropeptide Y Y1 antagonist, BIBP3226 (BIBP3226{(R)-N2-(diphenylacetyl)-N-[(4-hydroxyphenyl)methyl]-
-arginine-amide}). Neuropeptide Y, per se, had no vasoactive effect in the arteries. The potency of endothelin-1 was significantly decreased in congestive heart failure rats. Neuropeptide Y and neuropeptide Y-(13–36) potentiated the endothelin-1-induced contraction in congestive heart failure mesenteric arteries. In 20% of the congestive heart failure rats, sarafotoxin 6c induced a contraction of 31±4%. Neuropeptide Y also potentiated U46619- and noradrenaline-induced contractions but not 5-HT-induced contractions in congestive heart failure arteries. In sham-operated animals neuropeptide Y potentiated noradrenaline- and 5-HT-induced contractions. These potentiations were inhibited by BIBP3226. Acetylcholine induced an equipotent relaxation in both groups which was unaffected by neuropeptide Y. In conclusion, neuropeptide Y responses are altered in congestive heart failure rats. The potentiating effect differs between vasoactive substances. Neuropeptide Y Y1 and non-neuropeptide Y1 receptors are involved. 相似文献
109.
Katrina D. Ramsell Bai-Ge Zhao Daniel Baker Peter Cobbett 《Brain research bulletin》1996,39(2):109-114
The effects of serum on the morphological plasticity exhibited by pituicytes in explant cultures of the neurohypophysis of adult rats have been examined. Cultured pituicytes are normally nonstellate, protoplasmic, amorphous cells (< 25% are stellate with a distinct cell body and phase bright processes). After incubation (90 min) of pituicyte cultures in a HEPES buffered salt solution (HBSS) supplemented with isoproterenol or forskolin, the fraction of stellate pituicytes significantly increased. The increase in the fraction of stellate cells induced by isoproterenol was not reversed by subsequent incubation in isoproterenol-free HBSS for 90 min. In contrast, after stellation was induced in cultures by exposure to forskolin (90 min), the fraction of stellate cells was significantly reduced if these cultures were incubated in forskolin-free, serum (0.5%) supplemented HBSS for the same duration. Serum also blocked the increase in the fraction of stellate pituicytes induced by forskolin. These experiments suggest that serum components may have a significant role in controlling the plasticity of neuroglial relations in the neurohypophysis priviously demonstrated in vivo. 相似文献
110.
人体下颌牙槽骨皮质骨是各向异性复合生物材料,组织结构上类似于胶原羟磷灰石纤维增强的单向纤维增强复合材料。本文应用电测法测试了不同状态人体下颌牙槽骨皮质骨在平面应力状态下的各向异性弹性常数。 相似文献