全文获取类型
收费全文 | 300430篇 |
免费 | 6396篇 |
国内免费 | 286篇 |
专业分类
耳鼻咽喉 | 3145篇 |
儿科学 | 10592篇 |
妇产科学 | 5716篇 |
基础医学 | 33377篇 |
口腔科学 | 5842篇 |
临床医学 | 20024篇 |
内科学 | 62092篇 |
皮肤病学 | 4745篇 |
神经病学 | 26224篇 |
特种医学 | 11748篇 |
外国民族医学 | 1篇 |
外科学 | 44158篇 |
综合类 | 2932篇 |
一般理论 | 37篇 |
预防医学 | 30141篇 |
眼科学 | 5565篇 |
药学 | 18074篇 |
中国医学 | 1251篇 |
肿瘤学 | 21448篇 |
出版年
2023年 | 857篇 |
2022年 | 591篇 |
2021年 | 2722篇 |
2020年 | 1350篇 |
2019年 | 2994篇 |
2018年 | 26494篇 |
2017年 | 19842篇 |
2016年 | 21811篇 |
2015年 | 3912篇 |
2014年 | 4251篇 |
2013年 | 5961篇 |
2012年 | 16048篇 |
2011年 | 30412篇 |
2010年 | 23351篇 |
2009年 | 14743篇 |
2008年 | 26995篇 |
2007年 | 29699篇 |
2006年 | 8334篇 |
2005年 | 9857篇 |
2004年 | 10146篇 |
2003年 | 10703篇 |
2002年 | 8462篇 |
2001年 | 4108篇 |
2000年 | 4863篇 |
1999年 | 3468篇 |
1998年 | 706篇 |
1997年 | 512篇 |
1996年 | 398篇 |
1995年 | 348篇 |
1994年 | 274篇 |
1992年 | 1305篇 |
1991年 | 1140篇 |
1990年 | 1068篇 |
1989年 | 850篇 |
1988年 | 688篇 |
1987年 | 663篇 |
1986年 | 642篇 |
1985年 | 557篇 |
1984年 | 406篇 |
1983年 | 318篇 |
1979年 | 336篇 |
1975年 | 281篇 |
1974年 | 337篇 |
1973年 | 350篇 |
1972年 | 291篇 |
1971年 | 317篇 |
1970年 | 314篇 |
1969年 | 313篇 |
1968年 | 288篇 |
1967年 | 238篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Generoso Gómez Cruz Miguel Barrueco Ferrero Irene Aparicio Coca José Ángel Maderuelo Miguel Torrecilla García 《Archivos de bronconeumologia》2009,45(1):16-23
Background and ObjectiveSchool smoking prevention programs have never yielded the expected results. The aim of this study was to analyze the efficacy of an intensive smoking prevention program created by the educational community in which it was to be applied.Population and MethodA 3-year smoking prevention program was carried out among the students of Fuentesaúco Secondary School in Zamora, Spain. The Babilafuente Secondary School in Salamanca, Spain was the control group. The program included both prevention and treatment activities. The former were carried out in the school, in out-of-school situations, and in the community. The questionnaire of the European Smoking Prevention Framework Approach was used.ResultsA total of 417 students aged 12 to 17 years participated in the study. Of these, 54.4% belonged to the intervention group and 45.6% to the control group. Smokers represented 36.7% of the population. After the intervention smokers represented 40.1% of the Fuentesaúco students compared with 46.1% of the Babilafuente students, though the difference was not statistically significant. With respect to the cognitive determinants of smoking behavior, after the intervention significant differences in favor of the intervention group were only observed in the subjects’ perception of the behavior of their siblings, peers, and teachers.ConclusionsThe use of smoking prevention programs in schools should be reconsidered, and their evaluation should be based on educational rather than clinical criteria. Proposed changes in the program include decreasing its intensity, starting with students of an earlier age and seeking greater involvement of parents. 相似文献
102.
103.
Eduardo Carracedo-Martínez Agustin Pia-Morandeira 《Atencion primaria / Sociedad Espa?ola de Medicina de Familia y Comunitaria》2009,41(6):324-328
ObjectiveTo assess whether the release of the new consensus algorithms in August 2006, along with the consensus recommendation of also using metformin as first choice in patients with normal weight, has led to an increase in the use of this drug in the period immediately after.DesignRetrospective longitudinal Study.SitesSantiago de Compostela Health District (A Coruña).ParticipantsUsers of the Galician health service in the Santiago de Compostela Health District.MethodsThe evolution of the monthly number of DHD (Daily Defined Doses/1000 inhabitants/day) of metformin from early 2003 until 12 months after the issuing of new algorithms was analysed graphically and using a multiple regression model.ResultsThe graphical representation of the DHD of metformin over time shows a linear growth for the period, but there is an increasing trend after the publication of the new consensus algorithm. The multiple regression showed that the increase is statistically significant.ConclusionsFollowing the publication of the new consensus algorithm an increasing trend in the use of metformin is observed in the short term. 相似文献
104.
105.
David Jiménez Castro Gema Díaz David Martí Carlos Escobar Javier Ortega Sergio García-Rull Joaquin Picher Antonio Sueiro 《Blood coagulation & fibrinolysis》2007,18(2):173-177
This study aimed to determine whether a weight-adjusted dose of subcutaneous enoxaparin is as effective and safe as oral acenocoumarol for the secondary prophylaxis of pulmonary embolism. Three hundred and eighty consecutive noncancer outpatients hospitalized with an episode of symptomatic pulmonary embolism selected treatment with acenocoumarol or enoxaparin at a dose of 1 mg/kg once daily after being informed of the type of administration and expected frequency of laboratory monitoring for both medicinal products. Endpoints were symptomatic recurrent thromboembolic events evaluated by standard objective testing, and a composite endpoint of recurrent venous thromboembolism, major bleeding, and death from any cause. One hundred and ninety-nine patients (52%) chose acenocoumarol therapy and 181 chose enoxaparin monotherapy. Four patients in the enoxaparin group (2.2%) and six patients in the acenocoumarol group (3%) had an objective thromboembolic recurrence (hazard ratio, 1.35; 95% confidence interval, 0.38-4.79; P = 0.64). Nine patients in the enoxaparin group (5.0%) had a hemorrhagic complication compared with 11 in the acenocoumarol group (5.5%) (P = 0.81). The hospital length of stay was shorter with enoxaparin compared with acenocoumarol (11 versus 16 days, P = 0.0001). Enoxaparin is as effective and safe as acenocoumarol in the secondary prevention of recurrent thromboembolic disease and is associated with shorter hospitalization. 相似文献
106.
D-dimer has proved a useful diagnostic tool for the exclusion of deep venous thrombosis (DVT). The objective of this paper was to evaluate the diagnostic performance of a diagnostic algorithm combining clinical probability and D-dimer in outpatients receiving oral anticoagulant treatment (OAT) similar to those regularly applied to nonanticoagulated individuals. We enrolled 70 outpatients on OAT who presented with clinically suspected DVT; a standard diagnostic algorithm including clinical evaluation using the modified Wells score and a quantitative immunoturbidimetric D-dimer assay (STA Liatest D-Di; Diagnostica Stago, Asniéres sur Seine, France) was used. A 3-month follow-up period was applied for those patients in whom DVT was initially excluded. The prevalence of DVT was 18.5% (13/70); four of the diagnoses were made during the 3-month follow-up period. The sensitivity, specificity and negative predictive value of D-dimer were 69.2% (95 confidence interval, 42.4-87.3), 47.4% (95% confidence interval, 35.0-60.1) and 87.1% (95% confidence interval, 71.1-94.9), respectively. In conclusion, D-dimer is of limited value in outpatients on OAT presenting with clinically suspected DVT and should be omitted in such individuals; these patients should always undergo compression venous ultrasound, and repeat ultrasonography within 1 week might be warranted in cases with an initial negative examination. 相似文献
107.
Plasma levels and vascular effects of vasopressin in patients undergoing coronary artery bypass grafting. 总被引:1,自引:0,他引:1
Susana Novella Ana Cristina Martínez Rosa María Pagán Medardo Hernández Albino García-Sacristán Angel González-Pinto José María González-Santos Sara Benedito 《European journal of cardio-thoracic surgery》2007,32(1):69-76
OBJECTIVE: Recent studies have suggested that endogenous vasopressin (AVP) acts as a spasmogen during coronary artery bypass grafting (CABG). Given that AVP could induce vasospasm in the grafted vessel, we assessed the release of this peptide during and after CABG, and explored ways of counteracting its contractile effect on the internal mammary artery (IMA). METHODS: Plasma levels of AVP were determined by radioimmunoassay in 16 patients before, during and after CABG. Using isometric force recording techniques, we also investigated the mechanisms involved in the contractile effect of AVP in ring preparations of IMA specimens taken from 95 patients. RESULTS: Plasma AVP levels peaked after the start of cardiopulmonary bypass (CPB) and correlated well with serum osmolality (Pearson's r=0.9490; P<0.0001; n=16). An inverse correlation was observed between plasma AVP levels recorded at this stage and the maximal contraction induced in vitro by AVP in vascular rings from the same patients (Pearson's r=-0.6968; P<0.01; n=16). No change in the AVP response was produced by endothelium removal, exposure to the NO precursor (3 x 10(-4)M L-arginine), inhibition of nitric oxide (NO) synthase (3 x 10(-5) M L-NAME) or soluble guanylate cyclase (3 x 10(-6) M 1H-[1,2,4]oxadiazol [4,3,-alpha]quinoxalin-1-one (ODQ)), removal of the superoxide anion (100 U/ml superoxide dismutase (SOD) plus 1200 U/ml catalase) or hydroxyl radical (10(-4) M deferoxamine), or specific alpha1 - (10(-6) M prazosin) or endothelin (10(-5) M bosentan) receptor antagonism. In contrast, adenylate cyclase activation (3 x 10(-8) M forskolin) reduced the contractile response to AVP, while prostanoid synthesis (3 x 10(-6) M indomethacin) inhibition and blockade of Ca2+ -activated potassium channels (KCa) (10(-3) M tetraethylammonium (TEA)) enhanced AVP contraction. Age, gender and smoking also modified the AVP response. CONCLUSION: Our findings suggest a role for AVP as a modulator of vascular tone in human IMA. The effect of AVP is dependent on prostanoids and Ca2+ -activated K+ channels, so its dysfunction in pathophysiological cardiovascular processes could mean that AVP, among other factors, produces vasospasm in IMA grafts. 相似文献
108.
Michael Dietrich Christoph Meier Daniela Zeller Patrick Grueninger Roger Berbig Andreas Platz 《European journal of trauma and emergency surgery》2007,33(5):512-519
Abstract
Background: Primary shoulder hemiarthroplasty is an established treatment modality for complex fractures of the proximal humerus. Long-term
functional outcome is often disappointing. However, little is known about social implications particularly in the elderly.
Methods: A single-institution case series of consecutive geriatric patients (age > 70 years) treated with shoulder hemiarthroplasty
for complex fractures of the proximal humerus between 1994 and 1997 was analysed. Postoperative morbidity, long-term function,
radiological outcome and social implications were evaluated.
Results: Seventy-seven patients fulfilled the study criteria. Median age at the time of operation was 80 years (range 70–93 years).
Systemic and local postoperative complications were observed in 8% including 2 patients (3%) with revision surgery. Postoperative
mortality was 1%. Forty-eight patients (62%) were available for follow-up (median 49 months, range 25–80 months), 22 (29%)
died from causes unrelated to hemiarthroplasty before follow-up and 7 patients (9%) did not attend follow-up examination.
Median Constant-Murley score was 41 points (range 17–77 points). Long-term results concerning pain were satisfying. The Oxford
shoulder score ranged from 14 to 40 (median 30). Forty-one patients (85%) still lived in their original environment and managed
their daily life independently despite poor shoulder function. Four patients (8%) lived in a retirement home and 3 (6%) in
a nursery home. Eighty percent of our patients were still able to use public transportation, do the daily shopping and wash
their whole body by themselves.
Conclusion: Most patients managed their daily life independently despite poor shoulder function. 相似文献
109.
Marina H C G Magalh?es Cristiane Barbosa da Silveira Carla Ruffeil Moreira Marcelo Gusm?o Paraíso Cavalcanti 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,103(6):836-842
Mandibulofacial dysostosis (Treacher Collins Syndrome) is an autosomal dominant genetic disorder that probably derives from inhibition of the facial structures from the first and second branchial arches. The facial pattern of the syndrome is a convex facial profile with a prominent nose above a retruded chin. The eyes are deformed by antimongoloid slant of the palpebral fissures and facial bones are hypoplastic. The alterations are caused by mutation in gene 5q32-33.1, which encodes the nucleolar phosphoprotein treacle. Computed tomography images are able to demonstrate craniofacial bones, allowing the morphological analysis of these bones in individuals with complex deformities. The purpose of this paper is to present the results of a clinical and computed tomography investigation of two patients with Treacher Collins syndrome. 相似文献
110.
Dittmar Böckler Hardy Schumacher Klaus Klemm Marcel Riemensperger Philipp Geisbüsch Drosos Kotelis Harry Rotert Jens-Rainer Allenberg 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(6):715-723
OBJECTIVES: to report our experience with hybrid vascular procedures in patients with pararenal and thoracoabdominal aortic pathologies. METHODS: 68 patients were treated for thoracoabdominal aortic pathologies between October 1999 and February 2004; 19 patients (16 men; mean age 68, range 40-79) with high risk for open thoracoabdominal repair were considered to be candidates for combined endovascular and open repair. Aortic pathologies included five thoracoabdominal Crawford I aneurysms, one postdissection expanding aneurysm, three symptomatic plaque ruptures (Crawford IV), five combined thoracic descending and infrarenal aneurysms with a healthy visceral segment, three juxtarenal or para-anastomotic aneurysms, and two patients with simultaneous open aortic arch replacement and a rendezvous maneuver for thoracic endografting. Commercially available endografts were implanted with standardized endovascular techniques after revascularization of visceral and renal arteries. RESULTS: Technical success was 95%. One patient developed a proximal type I endoleak after chronic expanding type B dissection and currently is waiting conversion. Nine patients underwent elective, five emergency and five urgent (within 24 h) repair. 17 operations were performed simultaneously, and 2 as a staged procedure. Postoperative complications include two retroperitoneal hemorrhages, and one patient required long-term ventilation with preexisting subglottic tracheal stenosis. Thirty-day mortality was 17% (one multiple organ failure, one secondary rupture after open aortic arch repair, one myocardial infarction). Paraplegia or acute renal failure were not observed. Total survival rate was to 83% with a mean follow-up of 30 months. CONCLUSIONS: Midterm results of combined endovascular and open procedures in the thoracoabdominal aorta are encouraging in selected high risk patients. Staged interventions may reduce morbidity. 相似文献