全文获取类型
收费全文 | 29477篇 |
免费 | 1352篇 |
国内免费 | 614篇 |
专业分类
耳鼻咽喉 | 150篇 |
儿科学 | 1355篇 |
妇产科学 | 237篇 |
基础医学 | 2031篇 |
口腔科学 | 56篇 |
临床医学 | 3632篇 |
内科学 | 7562篇 |
皮肤病学 | 101篇 |
神经病学 | 650篇 |
特种医学 | 2055篇 |
外科学 | 2968篇 |
综合类 | 4921篇 |
预防医学 | 1771篇 |
眼科学 | 145篇 |
药学 | 2273篇 |
25篇 | |
中国医学 | 813篇 |
肿瘤学 | 698篇 |
出版年
2024年 | 37篇 |
2023年 | 396篇 |
2022年 | 1030篇 |
2021年 | 1121篇 |
2020年 | 976篇 |
2019年 | 810篇 |
2018年 | 847篇 |
2017年 | 788篇 |
2016年 | 890篇 |
2015年 | 927篇 |
2014年 | 2109篇 |
2013年 | 1937篇 |
2012年 | 1908篇 |
2011年 | 1954篇 |
2010年 | 1570篇 |
2009年 | 1594篇 |
2008年 | 1600篇 |
2007年 | 1632篇 |
2006年 | 1435篇 |
2005年 | 1256篇 |
2004年 | 903篇 |
2003年 | 738篇 |
2002年 | 549篇 |
2001年 | 578篇 |
2000年 | 456篇 |
1999年 | 431篇 |
1998年 | 343篇 |
1997年 | 320篇 |
1996年 | 233篇 |
1995年 | 286篇 |
1994年 | 242篇 |
1993年 | 173篇 |
1992年 | 161篇 |
1991年 | 129篇 |
1990年 | 126篇 |
1989年 | 117篇 |
1988年 | 107篇 |
1987年 | 99篇 |
1986年 | 65篇 |
1985年 | 87篇 |
1984年 | 87篇 |
1983年 | 25篇 |
1982年 | 75篇 |
1981年 | 48篇 |
1980年 | 46篇 |
1979年 | 54篇 |
1978年 | 45篇 |
1977年 | 32篇 |
1976年 | 22篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
心导纳微分环,肺导纳微分环最大向量正常值及其临床意义 总被引:2,自引:0,他引:2
本文报道3-50岁214例心导纳微分环(CADL)和肺导纳微分环(PADL)最大向量振幅及方位正常值,结果随增龄变化振幅递减,方位递增,多数男>女,部分组间有差异。48例左向右分流先心病环体最大向量与肺动脉压之间呈平行关系,并探讨其临床意义。 相似文献
102.
本研究分别给四组大鼠注射CCl_4、P_4、TNT及纯生油,进行亚慢性实验,在不同的时间处死动物,测定血清及肝组织NAG、CP、MAO、羟脯氨酸和肝组织病理观察。CCl_4染毒3周后就发生肝纤维化;P_4和TNT染毒12周后才发生肝纤维化。血清中NAG、CP及肝组织中NAG、羟辅氨酸含量在肝纤维化早期即有明显升高,其中血清NAG、CP与肝组织中羟脯氨酸含量有明显正相关关系。血清NAG、CP似可以用作了解肝纤维化情况的指标。 相似文献
103.
目的 评价棉尘对工人肺功能的影响。方法 对 14 6名接棉尘工人和 12 5名对照工人的肺活量(FVC)和第 1秒时间肺活量 (FEV1 0 )进行了检查。结果 前纺、后纺和细纱作业场所空气中的棉尘浓度几何均值分别为 (7 1± 8 7) ,(2 5± 1 7) ,(2 2± 2 4 )mg/m3 ,样品超标率 16 8%。接触组前纺、后纺工人的急性肺功能改变 (APFC)和前纺工人的慢性肺功能改变 (CPFC)检出率较对照组明显增高 (P <0 0 5 ) ,OR及 95 %CI分别为 4 7(1 4~ 16 3) ,4 5 (1 3~ 15 6 ) ,5 6 (1 1~ 2 9 8) ;4 0~岁年龄段接棉尘工人APFC检出率高于对照工人 (P <0 0 5 ) ,OR及 95 %CI为 9 0 (1 1~ 73 8) ;接棉尘女工APFC检出率也比对照女工高 (P <0 0 1)。结论 棉尘有损害肺通气功能的作用 ,以急性改变更为明显 相似文献
104.
目的:观察地塞米松对冷藏离体肺表面活性物质和顺应性的影响.方法:32只家兔肺随机均分为对照组、地塞米松冷藏(4℃)保存24h、72h、120h3个组.对照组:测定室温条件下的肺表面活性物质及顺应性.冷藏组:肺离体后立即置于含有地塞米松台式液中冷藏,在相应时间取出肺,室温条件下复温后,置入生理盐水中,测定肺表面活性物质,并测定注气(生理盐水)和抽气(生理盐水)过程中,肺容积在10ml、20ml、30ml时的肺顺应性.结果:冷藏24h组注水、抽水;72h组肺容积在10ml、20ml抽气、冷藏120h组在肺容积为10ml、20ml抽气的肺顺应性同对照组比较,差异无显著性(P>0.05).其余各组、项与对照组比较差异具有显著性(P<0.05),伴有表面活性物质的减少.结论:地塞米松冷藏离体肺顺应性增大,其影响程度随冷藏时间的延长而增加,同时伴有肺表面活性物质的减少. 相似文献
105.
Adrian Ooi Narain Moorjani Giedrius Baliulis Barry R. Keeton Anthony P. Salmon James L. Monro Marcus P. Haw 《European journal of cardio-thoracic surgery》2006,30(6):917-922
Objective: To assess the impact of early corrective surgery on the short and medium term outcome in tetralogy of Fallot (TOF). Materials and methods: All patients under 12 months of age undergoing correction of isolated TOF between February 1997 and July 2003 were reviewed retrospectively. Outcome data for mortality, post-operative care management, major morbidity and clinical follow-up were analysed. Results: Fifty-two operations were performed. The mean age at surgery was 5 months (range 1–12) of whom 16 (30.8%) were less than 3 months old, including 2 neonates, 22 (42.3%) were 3–6 months old and 14 (26.9%) were 7–12 months old. There was 1 (1.9%) early death caused by a cerebro-vascular accident and 1 (1.9%) late death secondary to acute infective endocarditis. There were no differences in post-operative morbidities attributable to age. Patients under 3 months old required greater duration of post-operative ventilation, ITU stay and in-hospital stay. At a mean follow-up of 4.0 years (range 1.5–8.0), 33 (63.5%) patients had well-tolerated pulmonary regurgitation (PR) and 3 (5.8%) patients required re-operation for right ventricular outflow tract obstruction (RVOTO). All patients had right bundle-branch-block but with QRS < 150 ms. Conclusion: Early definitive repair of TOF can be performed safely on patients under 6 months old. Age at surgery does not appear to affect the medium term haemodynamic outcome. However, early surgery does escalate the need for ICU care. This data suggests repair in asymptomatic patients be delayed until 3–6 months of age. 相似文献
106.
目的探讨极低出生儿体重儿转运过程中的有效护理措施,降低其死亡率。方法通过转运系统将基层医院32例极低出生体重儿转运至新生儿重症监护病房治疗,具体措施包括现场抢救,应用肺泡表面活性物质,途中连续监护和治疗。结果极低出生体重儿32例均成功转运,治愈出院13例,死亡19例,无一例途中死亡。结论全程监护,尽早转运及应用固尔苏是转运成功及降低极低出生体重儿死亡率的关键。 相似文献
107.
A panel of 377 healthy adults and 920 COPD patients aged 30–65 years, is annually interviewed (ATS-NHLI health questionnaire) and performs pulmonary function test (PFT), which includes: FVC, FEVI, FEVl/FVC, PEF, FEF50 and FEF75. Baseline data analysis showed a more significant excess in respiratory symptmos (8.8% to 21.4%) and lower PFT (2.4% to 8.0%) among patients occupationally exposed to dust, than among healthy exposed panelists (-0.7% to 7.7% excess symptomatology and -0.3 to 5.8% lower PFT). Among patients a significant correlation between PFT and degree of occupational dust exposure was found. Significantly lower FEVl/FVC and excess in respiratory symptoms (with relative risks of 2.47–16.38) was present in healty smokers vs. non smokers as compared with COPD patients.Corresponding author. 相似文献
108.
The influence of melatonin on tension of isolated bovine pulmonary vascular and bronchial smooth muscle rings were examined in these experiments. Melatonin caused a dose-dependent relaxation of precontracted (30 mM KCl) pulmonary artery and vein, although the effect is greater in arterial smooth muscle. This relaxant response was blocked by preincubating vessels with antagonists of vasoactive intestinal peptide or Substance P. In bronchial smooth muscle, melatonin caused a small contractile response. These experiments demonstrate that in response to melatonin the pulmonary vasculature relaxes, while in airway smooth muscle the reverse, constriction, occurs. It is hypothesized that nocturnal exaggeration of asthma may, in part, be due to changes in circulating levels of melatonin. 相似文献
109.
Stephen D Silberstein James J Corbett 《Cephalalgia : an international journal of headache》1993,13(3):212-213
Lumbar puncture is crucial in two distinct clinical situations in the diagnosis of the headache patient. The first is the patient who is suspected of having a symptomatic headache; the second is the patient with a chronic intractable or atypical headache disorder. This review discusses the usefulness of the lumbar puncture in the diagnosis of headache secondary to subarachnoid hemorrhage, meningitis, and intracranial hypotension and hypertension. The value of lumbar puncture in the presence of a normal CT/MRI scan is discussed. 相似文献
110.
Summary Substantiation of relevant asbestos risks by microscopic examination sets a lower detection limit at fibres longer than 5 to 10 m and thicker than 0.5 m Such microscopically detectable fibres are, of course, in respect to total quantity the insignificant part of the overall dust burden, but apparently a necessary part of the whole fraction when assessing the relevance of exposure. Until now, no epidemiologically conclusive asbestos risks resulting from occupational exposure have been made known solely with fibre fraction below the microscopic detection limit. Demands for supplementary electromicroscopic examination on the basis of case reports of lung parenchyma damage by fibres of a lower calibre than the microscopic detection limit are, therefore, presently without foundation. The subject examinations reveal that substantiation of asbestos risks with light-optical means, using different methods, provides comparable results. Initially, of course, it is surprising to obtain fluctuations in results of 100000 to 600000 asbestos particles for the same case. However, one must realize that calculations based on intermediate results are responsible for this range of fluctuation, due to the varying degree of asbestos fibre dispersion in the different sections of the lung and, depending on the method of detection used. Interest on the part of everyday occupational medicine and expert opinion is determined by the need to categorize individual cases into different basic classes of risk by referring to relevant morphological facts, such as substantiation of asbestosis or drawing a borderline between persons with occupational risk and those with a non-occupational risk. The subject examinations reveal, using different methods of analysis, equally significant results, which correspond with those published by other authors who used a method which, in terms of expenditure for material and manpower, is also suitable for routine analysis. 相似文献