全文获取类型
收费全文 | 2167823篇 |
免费 | 156124篇 |
国内免费 | 3036篇 |
专业分类
耳鼻咽喉 | 28442篇 |
儿科学 | 72504篇 |
妇产科学 | 59464篇 |
基础医学 | 310266篇 |
口腔科学 | 60471篇 |
临床医学 | 188132篇 |
内科学 | 413308篇 |
皮肤病学 | 44273篇 |
神经病学 | 172538篇 |
特种医学 | 87303篇 |
外国民族医学 | 529篇 |
外科学 | 330905篇 |
综合类 | 48410篇 |
现状与发展 | 3篇 |
一般理论 | 661篇 |
预防医学 | 171648篇 |
眼科学 | 49034篇 |
药学 | 161801篇 |
3篇 | |
中国医学 | 4404篇 |
肿瘤学 | 122884篇 |
出版年
2018年 | 38596篇 |
2017年 | 30288篇 |
2016年 | 33928篇 |
2015年 | 19290篇 |
2014年 | 26125篇 |
2013年 | 39553篇 |
2012年 | 58885篇 |
2011年 | 75397篇 |
2010年 | 50175篇 |
2009年 | 42023篇 |
2008年 | 71630篇 |
2007年 | 76688篇 |
2006年 | 58308篇 |
2005年 | 57851篇 |
2004年 | 58293篇 |
2003年 | 56653篇 |
2002年 | 53999篇 |
2001年 | 93463篇 |
2000年 | 97013篇 |
1999年 | 81665篇 |
1998年 | 22121篇 |
1997年 | 20061篇 |
1996年 | 20135篇 |
1995年 | 19525篇 |
1994年 | 18377篇 |
1993年 | 17363篇 |
1992年 | 67033篇 |
1991年 | 66319篇 |
1990年 | 65285篇 |
1989年 | 63061篇 |
1988年 | 58563篇 |
1987年 | 57738篇 |
1986年 | 54813篇 |
1985年 | 53037篇 |
1984年 | 39527篇 |
1983年 | 33976篇 |
1982年 | 19656篇 |
1981年 | 17738篇 |
1979年 | 37918篇 |
1978年 | 26569篇 |
1977年 | 22421篇 |
1976年 | 21277篇 |
1975年 | 22904篇 |
1974年 | 27851篇 |
1973年 | 26597篇 |
1972年 | 24731篇 |
1971年 | 23388篇 |
1970年 | 21562篇 |
1969年 | 20333篇 |
1968年 | 18730篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
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
62.
J Müller-Quernheim K I Gaede E Fireman G Zissel 《The European respiratory journal》2006,27(6):1190-1195
An increase in chronic beryllium disease (CBD) has been suggested due to higher industrial use of beryllium alloys. Since occupational CBD is a perfect phenocopy of sarcoidosis, it might be misdiagnosed as sarcoidosis. In the current it was hypothesised that CBD exists in cohorts of sarcoidosis patients. In a prospective case study, sarcoidosis patients were evaluated for potential beryllium exposure. In those patients in whom beryllium exposure was confirmed and beryllium hypersensitivity demonstrated, the diagnosis of sarcoidosis was rejected and corrected to CBD. In 84 patients seen for re-evaluation or making a diagnosis of sarcoidosis, beryllium exposure was recognised and a diagnosis of CBD was made in 34 out of 84 patients. The time lag between clinical diagnosis of sarcoidosis and the final diagnosis of CBD ranged 0-18 yrs (median 3 yrs) and the mean (range) age at time of diagnosis of CBD was 43.9(25-80) yrs. Beryllium-contaminated workplaces causing disease encompassed a wide spectrum of industries and technical trades in which beryllium-exposure is generally not perceived as a health hazard. In conclusion, chronic beryllium disease still belongs to the spectrum of differential diagnoses of granulomatous disorders. 相似文献
63.
64.
ATM-dependent DNA damage surveillance in T-cell development and leukemogenesis: the DSB connection 总被引:1,自引:0,他引:1
Summary: The immune system is capable of recognizing and eliminating an enormous array of pathogens due to the extremely diverse antigen receptor repertoire of T and B lymphocytes. However, the development of lymphocytes bearing receptors with unique specificities requires the generation of programmed double strand breaks (DSBs) coupled with bursts of proliferation, rendering lymphocytes susceptible to mutations contributing to oncogenic transformation. Consequently, mechanisms responsible for monitoring global genomic integrity must be activated during lymphocyte development to limit the oncogenic potential of antigen receptor locus recombination. Mutations in ATM (ataxia-telangiectasia mutated), a kinase that coordinates DSB monitoring and the response to DNA damage, result in impaired T-cell development and predispose to T-cell leukemia. Here, we review recent evidence providing insight into the mechanisms by which ATM promotes normal lymphocyte development and protects from neoplastic transformation. 相似文献
65.
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
66.
67.
68.
Tony R Cucuzzella Elva G Delport Nancy Kim Julie Marley Christine Pruitt Anton G Delport 《The spine journal》2006,6(4):364-369
BACKGROUND CONTEXT: Substantial variation exists regarding the use of sedation before interventional spine techniques. Patient preference should play an important role in decision making regarding the need for sedation. However, little is known about patients' anxiety levels before spinal injections and their perceptions about the necessity of sedation. PURPOSE: To determine patient perception for need for sedation before epidural steroid injections and zygapophyseal joint injections. STUDY DESIGN/SETTING: Survey of consecutive spinal injection patients in an outpatient spine center. PATIENT SAMPLE: 500 consecutive lumbar, thoracic, and cervical patients receiving spinal injections. OUTCOME MEASURES: A 12-item questionnaire assessing patients' perceived anxiety before to a spinal injection. METHODS: Subjects were given the questionnaire after their spinal injection. Percentages requesting sedation for a first and potential second procedure were assessed. Additionally, anxiety level and pain rating, location of injection, age, sex, and other medication use were analyzed to determine the effect on the request for sedation. RESULTS: 17% of patients questioned requested sedation before an injection, and 28% would request sedation if they were to have a second injection. CONCLUSIONS: Routine sedation before diagnostic and therapeutic injections is not necessary as the majority of patients would not request sedation before the procedure when given the option. However, in some patients sedation is indicated, and all patients would benefit from educational material on sedation before the injection. 相似文献
69.
70.
Severe adverse effects during the use of ovulation inhibitors occur mostly in women who have an elevated risk for the development of certain diseases owing to hereditary or acquired factors. By means of a careful personal or family history analysis as well as specific laboratory examinations, an existing predisposition may frequently be diagnosed and the individual risk associated with the use of oral contraceptive inhibitors may be estimated. The present contribution describes the potential effects of treatment with ovulation inhibitors on women with thrombophilia, cardiovascular disease, diabetes mellitus, dyslipidemia, overweight or underweight, tumors, psychiatric and neurological diseases and autoimmune disease. The hormonal methods and non-hormonal alternatives available for contraception are elucidated according to existing lesions and risk factors and the advantages and disadvantages are discussed. 相似文献