全文获取类型
收费全文 | 91531篇 |
免费 | 4701篇 |
国内免费 | 385篇 |
专业分类
耳鼻咽喉 | 1688篇 |
儿科学 | 2945篇 |
妇产科学 | 2161篇 |
基础医学 | 11879篇 |
口腔科学 | 3842篇 |
临床医学 | 6374篇 |
内科学 | 22082篇 |
皮肤病学 | 2766篇 |
神经病学 | 7235篇 |
特种医学 | 2374篇 |
外国民族医学 | 1篇 |
外科学 | 10732篇 |
综合类 | 598篇 |
一般理论 | 29篇 |
预防医学 | 9561篇 |
眼科学 | 1607篇 |
药学 | 6348篇 |
中国医学 | 586篇 |
肿瘤学 | 3809篇 |
出版年
2023年 | 640篇 |
2022年 | 1201篇 |
2021年 | 3069篇 |
2020年 | 1517篇 |
2019年 | 2745篇 |
2018年 | 3486篇 |
2017年 | 2086篇 |
2016年 | 2078篇 |
2015年 | 2372篇 |
2014年 | 3325篇 |
2013年 | 4574篇 |
2012年 | 6706篇 |
2011年 | 7220篇 |
2010年 | 3910篇 |
2009年 | 3177篇 |
2008年 | 5257篇 |
2007年 | 5467篇 |
2006年 | 5035篇 |
2005年 | 5006篇 |
2004年 | 4498篇 |
2003年 | 4124篇 |
2002年 | 3752篇 |
2001年 | 1977篇 |
2000年 | 2180篇 |
1999年 | 1784篇 |
1998年 | 672篇 |
1997年 | 564篇 |
1996年 | 467篇 |
1995年 | 414篇 |
1994年 | 340篇 |
1993年 | 292篇 |
1992年 | 755篇 |
1991年 | 593篇 |
1990年 | 552篇 |
1989年 | 474篇 |
1988年 | 448篇 |
1987年 | 420篇 |
1986年 | 372篇 |
1985年 | 349篇 |
1984年 | 222篇 |
1983年 | 231篇 |
1982年 | 166篇 |
1981年 | 162篇 |
1980年 | 149篇 |
1979年 | 186篇 |
1978年 | 147篇 |
1975年 | 116篇 |
1974年 | 150篇 |
1971年 | 122篇 |
1969年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
121.
Maria de Fátima Haueisen S. Diniz Valéria M. Azeredo Passos Marco Túlio C. Diniz 《Nutrition (Burbank, Los Angeles County, Calif.)》2010,26(10):925-931
ObjectiveThis review analyzes the literature concerning gut peptides and bariatric surgery, from 2005 to July 2009. In particular, we are interested in whether, and how, gastrointestinal peptide alterations following surgery interfere with appetite/satiety, and what role they might play in the resolution of comorbidities.Research methods and procedurePubMed/MEDLINE and ISI Web of Knowledge were used to search for human studies concerning gut peptides profiles after any bariatric operation technique.ResultsMost of the studies reviewed had longitudinal design, short follow-up, and low statistical power. The diversity of study results may be partially explained by methodological aspects. Glucagon-like peptide-1, gastric inhibitory peptide, and peptide YY alterations may contribute to the excellent results in glycemic control of diabetics. Results do vary depending on bariatric operation technique; this is particularly evident in the case of ghrelin, which has been much studied in recent years. Ghrelin suppression has been linked to increased satiety, alterations in energy homeostasis, and better glucose metabolism.ConclusionsThere is a lack of long-term data on gastrointestinal hormone profiles after bariatric surgery and the studies have many methodological pitfalls. We still need prospective, long-term, good methodological studies in this area. 相似文献
122.
123.
124.
125.
José Abal Arca Isaura Parente Lamelas Raquel Almazán Ortega José Blanco Pérez María Elena Toubes Navarro Pedro Marcos Velázquez 《Archivos de bronconeumologia》2009,45(10):502-507
Background and objectiveTo analyse frequency, characteristics and patient survival with lung cancer (LC) and Common Obstructive Pulmonary Disease (COPD), comparing them with patients that do not have COPD.Material and methodsA retrospective study, of patients diagnosed by means of cytohistology. Survival was estimated by the Kaplan-Meier method. Statistical analysis was carried out using SPSS 15.0.ResultsA total of 996 patients were diagnosed, 39.8% with COPD. Mean age70±9.19 years. GOLD stages: I 18.2%, II 53.6%, III 24%, IV 4.2%. The histological types: squamous cell carcinoma 48.2%, adenocarcinoma 22%, and small cell carcinoma 22.5%. Survival was longer in the COPD group.ConclusionsLC and COPD are combined in 39.8%. Squamous cell type is more frequent and survival was longer in the COPD group. 相似文献
126.
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
127.
128.
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
129.
Summary We conducted a survey of the presence, prevalence and diversity of gastrointestinal helminths in faecal samples and stomach
contents of three turtle species, — Erymnochelys madagascariensis (Chelonia: Podocnemididae), Pelomedusa subrufa and Pelusios castanoides (Chelonia: Pelomedusidae), — from several localities in Madagascar. Four nematode species were detected: Atractis chabaudi, Camallanus chelonius, Falcaustra pelusios, and Spiroxys sp. E. madagascariensis, with all four species, had the greatest helminth diversity. A. chabaudi was the community’s core species, whereas Spiroxys sp. was a satellite species. Only two species (A. chabaudi and Spiroxys sp.) were found in P. subrufa and only one, Spiroxys sp., in P. castanoides. These are the first helminthological data on E. madagascariensis, one of the most threatened freshwater turtles in the world. 相似文献
130.
JA HYEON KU CHEOL KWAK SEUNG-JUNE OH EUNSIK LEE SANG EUN LEE JAE-SEUNG PAICK 《International journal of urology》2004,11(7):489-493
BACKGROUND: Our aims in the present study were to estimate the influences of pain and urinary symptoms on quality of life, and to determine which of these two variables has the most predictive power with respect to quality of life in young men with chronic prostatitis-like symptoms. METHODS: Chronic prostatitis-like symptoms were measured by the National Institutes of Health-Chronic Prostatitis Symptom Index. Of the 28,841 men aged 20 years who lived in the study community, 18,495 men (a response rate 64.1%) agreed to participate in the study. A total of 1057 men who complained of symptoms indicative of chronic prostatitis were included in the study. The influences of pain and urinary symptoms on quality of life were determined using logistic regression analysis. The receiver operating characteristic (ROC) curve was used to estimate the predictive ability of each of these variables with respect to quality of life. RESULTS: Results from multivariate analysis showed that both pain and urinary symptoms were associated with an increased likelihood of impaired quality of life, although pain contributed more to a reduced quality of life than urinary symptoms. Relative to men who experienced mild pain, men who experienced moderate pain had a 3.9-fold risk of poor quality of life (odds ratio [OR], 3.87; 95% confidence interval [CI], 2.86-5.23; P < 0.001) and those who experienced severe pain had a 15.7-fold risk of reduced quality of life (OR, 15.68; 95% CI, 6.59-37.35; P < 0.001). Moderate urinary symptoms were associated with a 1.4-fold risk of bother (OR, 1.41; 95% CI, 1.01-1.99; P < 0.001) and severe urinary symptoms were associated with 2.4-fold risk (OR, 2.39; 95% CI, 1.37-4.12; P < 0.001), relative to mild urinary symptoms. Comparison of the effects of pain and urinary symptoms showed that pain severity had the most predictive power for bother, quality of life, and quality-of-life impact. The areas under the ROC curves for bother, quality of life, and quality-of-life impact were 71.3%, 69.3% and 72.5%, respectively. CONCLUSION: Urinary symptoms and pain might be associated with an increased likelihood of impaired quality of life in young men with chronic prostatitis-like symptoms. In addition, our findings suggest that pain severity is the most influential variable for determining quality of life in this population. 相似文献