全文获取类型
收费全文 | 23474篇 |
免费 | 2645篇 |
国内免费 | 859篇 |
专业分类
耳鼻咽喉 | 202篇 |
儿科学 | 450篇 |
妇产科学 | 171篇 |
基础医学 | 2089篇 |
口腔科学 | 244篇 |
临床医学 | 2329篇 |
内科学 | 3173篇 |
皮肤病学 | 189篇 |
神经病学 | 1719篇 |
特种医学 | 1998篇 |
外国民族医学 | 3篇 |
外科学 | 1442篇 |
综合类 | 3834篇 |
现状与发展 | 1篇 |
预防医学 | 1928篇 |
眼科学 | 1404篇 |
药学 | 3585篇 |
18篇 | |
中国医学 | 1284篇 |
肿瘤学 | 915篇 |
出版年
2024年 | 56篇 |
2023年 | 313篇 |
2022年 | 695篇 |
2021年 | 987篇 |
2020年 | 958篇 |
2019年 | 937篇 |
2018年 | 961篇 |
2017年 | 1001篇 |
2016年 | 1055篇 |
2015年 | 984篇 |
2014年 | 1614篇 |
2013年 | 1680篇 |
2012年 | 1621篇 |
2011年 | 1666篇 |
2010年 | 1330篇 |
2009年 | 1031篇 |
2008年 | 1193篇 |
2007年 | 1172篇 |
2006年 | 1107篇 |
2005年 | 849篇 |
2004年 | 731篇 |
2003年 | 631篇 |
2002年 | 538篇 |
2001年 | 502篇 |
2000年 | 425篇 |
1999年 | 327篇 |
1998年 | 234篇 |
1997年 | 243篇 |
1996年 | 214篇 |
1995年 | 246篇 |
1994年 | 201篇 |
1993年 | 164篇 |
1992年 | 149篇 |
1991年 | 128篇 |
1990年 | 115篇 |
1989年 | 106篇 |
1988年 | 80篇 |
1987年 | 89篇 |
1986年 | 66篇 |
1985年 | 119篇 |
1984年 | 107篇 |
1983年 | 85篇 |
1982年 | 71篇 |
1981年 | 55篇 |
1980年 | 42篇 |
1979年 | 37篇 |
1978年 | 22篇 |
1977年 | 13篇 |
1976年 | 8篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
81.
观察了小鼠暴露在不同海拔梯度下脑含水量改变及其与脑水肿的关系。实验结果表明,小鼠由低海拔区快速进入高海拔区后脑组织的湿干比值和含水量均有增高(P<001),以进入高海拔区后的第7d为最高峰。组织学观察表明,此时脑神经细胞肿胀,胞浆内有空泡变性,胶质细胞和微血管周围有明显空晕。以上结果揭示,由低海拔区快速进入高海拔区后可致脑水肿形成。 相似文献
82.
女性飞行学员高空飞行生理生化耐受能力研究 总被引:1,自引:0,他引:1
为从高空缺氧耐力训练前后生理、生化角度探讨中国女飞行员驾驶战斗机的可行性,在地面模拟高空缺氧及高空飞行训练前后行心电图、心率、血氧饱和度、血压、血尿酸(BUA)、肌酸激酶(CK)、血红蛋白(Hb)、乳酸(BLA)、肌酐(Cr)和天冬氨酸转氨酶(AST)测定,并与男飞行学员的测定结果比较.发现男女飞行学员的心电图、心率、血氧饱和度、血压、Cr、CK、BUA和AST均无显著性差异;女飞行学员在高空耐缺氧Hb代偿反应高于男飞行学员(P<0.05),而BLA水平低于男飞行学员(P<0.05).认为中国女飞行学员在生理生化耐受能力上能胜任飞战斗机. 相似文献
83.
不同类型高危儿早期干预的临床研究 总被引:4,自引:0,他引:4
目的 探索早期干预对窒息、高胆、早产三类高危儿智力发育改善的效果,寻找更合适的早期干预措施。方法 将三类高危儿分为干预组及对照组,同时随机选取正常对照组进行随访。干预组采用鲍秀兰教授“0~3岁”早期干预方案训练,各组均在6个月、1岁时分别采用婴幼儿智能发育量表(CDCC)进行智力发育测评,结果用MDI、PDI表示。结果 (1)6个月龄时MDI各干预组与对照组间有显著性差异,窒息组、早产组与正常组间亦有显著性差异;高胆组与正常组间无差异;PDI窒息组中干预组与对照组之间有显著差异(P<0.01),高胆组、早产组均无差异(P>0.05)。(2)1岁时MDI和PDI结果一致,干预组与对照组间比较窒息组、高胆组有显著差异,早产组无差异;窒息组、高胆组干预组与正常组比较无差异,对照组和早产组与正常组比较均有显著差异(P<0.01)。(3)所有干预组测评分值均高于对照组,6个月与1岁之间比较有显著差异,各观察组间比较有显著性差异(P<0.01)。结论 三类高危儿早期干预效果差异较大,干预组均较对照组分值高,早期干预有改善智力发育的作用;三类高危儿中,窒息组、高胆组效果最好,均达到或超过正常水平。所有未干预组均不及正常水平;早期干预对足月高危儿效果显著,对早产儿欠佳,远期效果尚需进一步随访观察。 相似文献
84.
为探讨优质为兵服务,促进医院全面建设,本阐述了“开展优质服务达标创先”活动的意义,指明该活动的重点是:加强医德医风建设;坚持依法治医;加强内涵建设,确保合理医疗。提出现阶段应着力抓好以下几个方面工作:坚决纠正乱收费;坚决纠正收取“红包”,礼品,坚决纠正服务作风粗疏。 相似文献
85.
目的:考察新药依西美坦片在3种不同介质中的溶出特性,以研究影响其口服吸收速率的主要因素和规律。方法:建立HPLC法检测其制剂含量和溶出液浓度,色谱柱:HypersilC18(150mm×4.6mm,5μm);流动相:甲醇:0.05mol/LKH2PO4溶液(60:40);检测波长:247nm。溶出介质选用水、0.1mol/L盐酸溶液及0.5%十二烷基硫酸钠溶液,采用转篮法,转速100r/min。结果:依西美坦片在水和0.1mol/L盐酸溶液中的溶出较差,在0.5%十二烷基硫酸钠溶液巾溶出迅速完全,60min时在3种介质中的溶出百分率分别为(60.25±3.76)%、(47.57±1.20)%和(82.24±0.96)%。结论:依西美坦片可能主要在肠道溶出,其溶出速率受介质影响大。 相似文献
86.
PEMMARAJU NARASIMHA RAO JAMES E. BURDETT JAMES W. CESSAC CECIL M. DiNUNNO DOROTHY M. PETERSON HYUN K. KIM 《Chemical biology & drug design》1987,29(1):118-125
The DL-arylamino acid ethyl ester derivatives of β-(3-pyridyl)-DL-alanine, and β-(3-benzo[b]thienyl)-DL-alanine were synthesized by diethyl acetamidomalonate condensation with the respective arylmethyl halides followed by partial hydrolysis to the monoethyl ester and decarboxylation. Each derivative was enzymatically resolved to a separable mixture of the corresponding N-acetyl-L-amino acid and the unchanged D amino acid derivative. Acidic hydrolysis of the latter gave the corresponding D-amino acid, the optical purity of which was established by HPLC analysis of the 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate (GITC) derivative. The free D amino acids were converted to D-BOC derivatives by reaction with di-tert-butyldicarbonate in tert-butyl alcohol, water and sodium hydroxide. 相似文献
87.
Comparison of the haemodynamic effects of intermittent positive pressure ventilation with high frequency jet ventilation 总被引:1,自引:0,他引:1
The cardiorespiratory effects of intermittent positive pressure ventilation and high frequency jet ventilation with and without positive end expiratory pressure were compared in patients following valvular heart surgery (mitral and/or aortic). Twenty patients received intermittent positive pressure ventilation and high frequency jet ventilation with 0, 0.5 and 1.0 kPa positive end expiratory pressure. High frequency jet ventilation was well tolerated. The addition of 1.0 kPa positive end expiratory pressure was associated with preservation of the arterial oxygen tension without any increase in shunt or significant adverse haemodynamic effect. The results are discussed and compared with a previous study of high frequency jet ventilation following aortocoronary bypass graft surgery. 相似文献
88.
高强度聚焦超声及其医学应用 总被引:1,自引:0,他引:1
HIFU技术的研究在国内外已掀起了热潮.到目前为止.HIFU技术已得到广泛的实验和临床支持。本文将对HIFU治疗设备的总体结构做一阐述.并讨论其在医学领域中的应用及发展方向。 相似文献
89.
L. J. CHESKIN M. D. CROWELL N. KAMAL B. ROSEN M. M. SCHUSTER W. E. WHITEHEAD 《Neurogastroenterology and motility》1992,4(3):173-177
Abstract Changes in colonic motor activity during aerobic exercise were investigated in ten regularly exercising volunteers (five males and five females) aged 27–70 years. Motility was recorded with a catheter containing three solid-state pressure transducers spaced 5 cm apart. The motility catheter was advanced 40–50 cm from the anal verge by flexible sigmoidoscope without anesthesia at least 60 min prior to testing. Manometric recordings were made from the colon during a 1-h pre-exercise rest period, 1 h of jogging at 70–80% maximum heart rate, and 1-h post-exercise rest period. The dominant frequency of contractile activity in the colon shifted from 1–4 cpm during rest, to 4–9 cpm with the onset of exercise. Activity also shifted from sporadic, isolated contractions to regular, propagated contractions in six of ten subjects, five of whom reported a history of runner's diarrhoea. The dominant frequency returned to 1–4 cpm during the post-exercise period. These changes in distal colonie motility may account for the diarrhoea which some subjects experience during intense, acute exercise. 相似文献
90.
Yoshio Takesue Takashi Yokoyama Takashi Kodama Yoshiaki Murakami Yuji Imamura Yuichiro Matsuura 《Surgery today》1997,27(5):392-397
This study was designed to determine the influence of ileal pouch capacity and anal sphincteric function on the clinical outcome
after ileal pouch-anal anastomosis. A total of 24 patients who had undergone ileal pouch-anal anastomosis (J pouch) for ulcerative
colitis were studied. The 24-hour stool frequency was found to be inversely correlated with the sensitivity threshold volume
(STV), maximal tolerance volume (MTV), and distensibility, but was independent of the maximal resting pressure and maximal
squeeze pressure. Patients experiencing nocturnal fecal incontinence had maximal resting pressures that were significantly
lower than those of nocturnally continent patients. Among the patients with fecal incontinence, those with frequent soiling
had lower resting pressures, STV, and distensibility than the patients with intermittent spotting. In addition, the STV in
patients needing nocturnal evacuation were lower than those of patients who did not evacuate after falling asleep. The conclusions
are as follows. Both stool frequency and the need for nocturnal pouch evacuation correlated directly with pouch volume. Anal
incontinence was more common in patients with low internal sphincteric function. In addition, frequent and gross nocturnal
incontinent patients demonstrate a worse function in both the anal sphincter and reservoir than those with intermittent spotting. 相似文献