全文获取类型
收费全文 | 1415959篇 |
免费 | 113866篇 |
国内免费 | 3342篇 |
专业分类
耳鼻咽喉 | 18471篇 |
儿科学 | 46765篇 |
妇产科学 | 41188篇 |
基础医学 | 201450篇 |
口腔科学 | 38001篇 |
临床医学 | 126341篇 |
内科学 | 285540篇 |
皮肤病学 | 33479篇 |
神经病学 | 117262篇 |
特种医学 | 53967篇 |
外国民族医学 | 464篇 |
外科学 | 211241篇 |
综合类 | 32781篇 |
现状与发展 | 3篇 |
一般理论 | 487篇 |
预防医学 | 110560篇 |
眼科学 | 31567篇 |
药学 | 98840篇 |
1篇 | |
中国医学 | 3379篇 |
肿瘤学 | 81380篇 |
出版年
2021年 | 11040篇 |
2019年 | 11831篇 |
2018年 | 16787篇 |
2017年 | 12813篇 |
2016年 | 14393篇 |
2015年 | 16140篇 |
2014年 | 22757篇 |
2013年 | 33660篇 |
2012年 | 45725篇 |
2011年 | 48310篇 |
2010年 | 28422篇 |
2009年 | 27234篇 |
2008年 | 44604篇 |
2007年 | 47112篇 |
2006年 | 47640篇 |
2005年 | 46113篇 |
2004年 | 43996篇 |
2003年 | 41902篇 |
2002年 | 40355篇 |
2001年 | 73107篇 |
2000年 | 74646篇 |
1999年 | 61656篇 |
1998年 | 17028篇 |
1997年 | 15458篇 |
1996年 | 15606篇 |
1995年 | 14815篇 |
1994年 | 13424篇 |
1993年 | 12612篇 |
1992年 | 45897篇 |
1991年 | 43515篇 |
1990年 | 41535篇 |
1989年 | 39600篇 |
1988年 | 36220篇 |
1987年 | 35388篇 |
1986年 | 32886篇 |
1985年 | 31308篇 |
1984年 | 23847篇 |
1983年 | 20044篇 |
1982年 | 12217篇 |
1981年 | 10782篇 |
1979年 | 20716篇 |
1978年 | 14585篇 |
1977年 | 12089篇 |
1976年 | 11380篇 |
1975年 | 11633篇 |
1974年 | 14003篇 |
1973年 | 13549篇 |
1972年 | 12641篇 |
1971年 | 11481篇 |
1970年 | 10922篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
R H Green C E Brightling S McKenna B Hargadon N Neale D Parker C Ruse I P Hall I D Pavord 《The European respiratory journal》2006,27(6):1144-1151
There is increasing evidence that the assessment of eosinophilic airway inflammation using induced sputum and measurement of airway hyperresponsiveness provides additional, clinically important information concerning asthma control. The aim of this study was to directly compare the effects of different treatments on these markers in patients with asthma and persistent symptoms, despite the use of low-dose inhaled corticosteroids. A double-blind four-way crossover study was performed, which compared a 1-month treatment with budesonide 400 mug b.i.d., additional formoterol, additional montelukast and placebo in 49 patients with uncontrolled asthma despite budesonide 100 mug b.i.d., with each treatment separated by a 4-week washout period. The change in sputum eosinophil count with formoterol (2.4 to 3.8% change, 0.6-fold reduction, 95% confidence interval (CI) 0.5-0.9) differed significantly from placebo (2.8 to 2.5% change, 1.1-fold reduction, 95% CI 0.7-1.6) and high-dose budesonide (2.7 to 1.6% change, 1.6-fold reduction, 95% CI 1.2-2.2). The effects of montelukast did not differ from placebo. The changes in methacholine airway responsiveness were small and did not differ between treatments. High-dose budesonide had the broadest range of beneficial effects on other outcomes, including symptom scores, morning peak expiratory flow and forced expiratory volume in one second. In conclusion, treatment given in addition to low-dose inhaled corticosteroids results in modest benefits. Formoterol and high-dose budesonide have contrasting effects on eosinophilic airway inflammation. 相似文献
42.
C T Gan G P McCann J T Marcus S A van Wolferen J W Twisk A Boonstra P E Postmus A Vonk-Noordegraaf 《The European respiratory journal》2006,28(6):1190-1194
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function. 相似文献
43.
44.
C. M. Crceles J. M. Serrano P. Marín E. Escudero E. Fernndez‐Varn 《Transboundary and Emerging Diseases》2006,53(6):300-304
The pharmacokinetics (PK) of moxifloxacin in healthy white New Zealand rabbits was studied following intravenous (IV) and subcutaneous (SC) administration routes as well as a SC long‐acting poloxamer 407 gel formulation (SC‐P407). Moxifloxacin concentrations were determined by high‐performance liquid chromatography assay with fluorescence detection. Mean half‐life for IV, SC and SC‐P407 routes was 2.15, 5.41 and 11.09 h. Clearance value after IV dosing was 0.78 l/kg/h. After SC administration, the mean absolute bioavailability was 117% and the Cmax was 1.61 ± 0.49 mg/l. After SC‐P407 administration, the bioavailability was 44% and the Cmax 1.83 was ±0.62 mg/l. No adverse effects were observed in any of the rabbits following IV, SC and SC‐P407 administration of moxifloxacin. Minimal inhibitory concentrations of moxifloxacin against different strains of Staphylococcus aureus from different european countries were used to compute the main pharmacodynamic (PD) surrogate markers of efficacy. The high tolerability of this SC‐P407 formulation and the favourable PK behaviour such as the long half‐life, acceptable bioavailability and excellent PK–PD ratios achieved indicate that it is likely to be effective in rabbits. 相似文献
45.
C Berg F Bender M Soukup A Geipel R Axt-Fliedner J Breuer U Herberg U Gembruch 《Ultrasound in obstetrics & gynecology》2006,28(7):882-889
OBJECTIVE: To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life. METHODS: This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers. RESULTS: In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted. CONCLUSIONS: RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations. 相似文献
46.
Sandeep Gohar Devendra Desai Anand Joshi Anita Bhaduri Ramesh Deshpande C Balkrishna Mukesh Chawla Camila Rodrigues V R Joshi 《Indian journal of gastroenterology》2003,22(4):140-142
INTRODUCTION: Autoimmune hepatitis (AIH) is a well-defined entity in the West but there are sparse Indian data on this disease. AIM: To study the clinical profile and response to treatment of Indian patients with AIH. METHODS: This is a part retrospective and part prospective study of 50 patients (median age 48 years, range 11-82; 43 women) seen between 1995 to 2001, diagnosed to have AIH as per the revised scoring system. Clinical and laboratory profile, response to treatment, and complications of treatment were analyzed. RESULTS: AIH accounted for 6% of all patients with liver disease seen during the period. The presenting symptoms were gastrointestinal in 43 and non-gastrointestinal in 7, with median symptom duration of 6 months (range 2 weeks to 40 years). Forty patients (80%) had chronic liver disease. Associated illnesses were present in 28 patients. Twenty-six patients were classified as definite and the rest as probable AIH. Forty-nine patients had Type 1 AIH. Five patients had overlap syndrome. Forty-five patients (90%) received immunosuppressive therapy. Twelve of 18 patients receiving only prednisolone and 21 of 27 patients receiving prednisolone and azathioprine combination responded. Thirteen (26%) patients had therapy-related complications (infectious 5, non infectious 8) with two treatment-related deaths. CONCLUSION: Type 1 AIH was the predominant type of AIH. The majority of patients with AIH presented with chronic liver disease. There was good response to immunosuppressive therapy. Therapy-related complications occurred in one-fourth of patients. 相似文献
47.
48.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section. 相似文献
49.
50.