全文获取类型
收费全文 | 254737篇 |
免费 | 17607篇 |
国内免费 | 1019篇 |
专业分类
耳鼻咽喉 | 2674篇 |
儿科学 | 6667篇 |
妇产科学 | 5199篇 |
基础医学 | 32104篇 |
口腔科学 | 4848篇 |
临床医学 | 26452篇 |
内科学 | 53968篇 |
皮肤病学 | 3509篇 |
神经病学 | 25220篇 |
特种医学 | 10821篇 |
外国民族医学 | 13篇 |
外科学 | 39450篇 |
综合类 | 2970篇 |
现状与发展 | 1篇 |
一般理论 | 209篇 |
预防医学 | 18665篇 |
眼科学 | 5839篇 |
药学 | 17230篇 |
1篇 | |
中国医学 | 329篇 |
肿瘤学 | 17194篇 |
出版年
2023年 | 1411篇 |
2022年 | 2298篇 |
2021年 | 5582篇 |
2020年 | 3208篇 |
2019年 | 5346篇 |
2018年 | 6373篇 |
2017年 | 4698篇 |
2016年 | 5111篇 |
2015年 | 6020篇 |
2014年 | 8760篇 |
2013年 | 11806篇 |
2012年 | 18115篇 |
2011年 | 18850篇 |
2010年 | 10517篇 |
2009年 | 9723篇 |
2008年 | 16601篇 |
2007年 | 17532篇 |
2006年 | 17008篇 |
2005年 | 16860篇 |
2004年 | 15892篇 |
2003年 | 14525篇 |
2002年 | 13909篇 |
2001年 | 2647篇 |
2000年 | 2220篇 |
1999年 | 2656篇 |
1998年 | 3019篇 |
1997年 | 2412篇 |
1996年 | 2124篇 |
1995年 | 1987篇 |
1994年 | 1729篇 |
1993年 | 1680篇 |
1992年 | 1493篇 |
1991年 | 1455篇 |
1990年 | 1294篇 |
1989年 | 1251篇 |
1988年 | 1145篇 |
1987年 | 1098篇 |
1986年 | 1068篇 |
1985年 | 1083篇 |
1984年 | 1262篇 |
1983年 | 1070篇 |
1982年 | 1250篇 |
1981年 | 1144篇 |
1980年 | 992篇 |
1979年 | 746篇 |
1978年 | 791篇 |
1977年 | 639篇 |
1976年 | 617篇 |
1975年 | 504篇 |
1974年 | 518篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Richard J. Bloomer Andrew C. Fry Michael J. Falvo Christopher A. Moore 《Journal of Science and Medicine in Sport》2007,10(6):411-417
The purpose of this investigation was to determine if a single set of strenuous squat exercise would result in an acute oxidative stress, as demonstrated previously by a single sprint. Thirteen resistance trained men performed one set of 15 repetitions of barbell squats using 70% of one repetition maximum and a 30 s maximal cycle sprint on two different occasions. The total work performed was calculated for each exercise bout. Heart rate, perceived exertion, blood lactate, protein carbonyls, 8-hydroxydeoxyguanosine, and malondialdehyde were measured before and within 1 min following exercise. No differences were noted between the squat and sprint tests for total work, heart rate or perceived exertion. An exercise test by time interaction was evident for blood lactate with values greater following sprinting compared to squatting (P = 0.0005). Postexercise protein carbonyls were not different between exercise tests but were elevated above rest (P = 0.04) by 111% and 74% following sprinting and squatting, respectively, while 8-hydroxydeoxyguanosine and malondialdehyde were relatively unaffected by either exercise test. These data indicate that a single bout of strenuous squatting and sprinting performed by resistance trained men results in elevated protein carbonyls, while having little impact on 8-hydroxydeoxyguanosine or malondialdehyde during the immediate postexercise period. 相似文献
942.
Jessica Lasky-Su Tobias Banaschewski Jan Buitelaar Barbara Franke Keeley Brookes Edmund Sonuga-Barke Richard Ebstein Jacques Eisenberg Michael Gill Iris Manor Ana Miranda Fernando Mulas Robert D Oades Herbert Roeyers Aribert Rothenberger Joseph Sergeant Hans-Christoph Steinhausen Eric Taylor Kaixin Zhou Margaret Thompson Philip Asherson Stephen V Faraone 《Neuropsychopharmacology》2007,62(9):985-990
BACKGROUND: Previous research found an association between single nucleotide polymorphisms (SNPs) in the promoter region of DRD4 and statistically derived phenotypes generated from attention-deficit/hyperactivity disorder (ADHD) symptoms. We sought to replicate this finding by using the same methodology in an independent sample of ADHD individuals. METHODS: Four SNPs were genotyped in and around DRD4 in 2631 individuals in 642 families. We developed a quantitative phenotype at each SNP by weighting nine inattentive and nine hyperactive-impulsive symptoms. The weights were selected to maximize the heritability at each SNP. Once a quantitative phenotype was generated at each SNP, the screening procedure implemented in PBAT was used to select and test the five SNPs/genetic model combinations with the greatest power to detect an association for DRD4. RESULTS: One of the four SNPs was associated with the quantitative phenotypes generated from the ADHD symptoms (corrected p-values = .02). A rank ordering of the correlation between each of the ADHD symptoms and the quantitative phenotype suggested that hyperactive-impulsive symptoms were more strongly correlated with the phenotype; however, including inattentive symptoms was necessary to achieve a significant result. CONCLUSIONS: This study partially replicated a previous finding by identifying an association between rs7124601 and a quantitative trait generated from ADHD symptoms. The rs7124601 is in linkage disequilibrium (LD) with the SNPs identified previously. In contrast to the previous study, this finding suggests that both hyperactive-impulsive and inattentive symptoms are important in the association. 相似文献
943.
Timothy M. Pawlik Ana Luiza Gleisner Luca Vigano David A. Kooby Todd W. Bauer Andrea Frilling Reid B. Adams Charles A. Staley Eduardo N. Trindade Richard D. Schulick Michael A. Choti Lorenzo Capussotti 《Journal of gastrointestinal surgery》2007,11(11):1478-1487
Re-resection for gallbladder carcinoma incidentally discovered after cholecystectomy is routinely advocated. However, the
incidence of finding additional disease at the time of re-resection remains poorly defined. Between 1984 and 2006, 115 patients
underwent re-resection at six major hepatobiliary centers for gallbladder carcinoma incidentally discovered during cholecystectomy.
Data on clinicopathologic factors, operative details, TNM tumor stage, and outcome were collected and analyzed. Data on the
incidence and location of residual/additional carcinoma discovered at the time of re-resection were also recorded. On pathologic
analysis, T stage was T1 7.8%, T2 67.0%, and T3 25.2%. The median time from cholecystectomy to re-resection was 52 days. At
the time of re-resection, hepatic surgery most often consisted of formal segmentectomy (64.9%). Patients underwent lymphadenectomy
(LND) (50.5%) or LND + common bile duct resection (43.3%). The median number of lymph nodes harvested was 3 and did not differ
between LND alone (n = 3) vs LND + common duct resection (n = 3) (P = 0.35). Pathology from the re-resection specimen noted residual/additional disease in 46.4% of patients. Of those patients
staged as T1, T2, or T3, 0, 10.4, and 36.4%, respectively, had residual disease within the liver (P = 0.01). T stage was also associated with the risk of metastasis to locoregional lymph nodes (lymph node metastasis: T1 12.5%;
T2 31.3%, T3 45.5%; P = 0.04). Cystic duct margin status predicted residual disease in the common bile duct (negative cystic duct, 4.3% vs positive
cystic duct, 42.1%) (P = 0.01). Aggressive re-resection for incidental gallbladder carcinoma is warranted as the majority of patients have residual
disease. Although common duct resection does not yield a greater lymph node count, it should be performed at the time of re-resection
for patients with positive cystic duct margins because over one-third will have residual disease in the common bile duct.
Presented at the 48th Annual Meeting of the Society for Surgery of the Alimentary Tract at Digestive Week 2007, Plenary Session,
Washington, DC, March 23, 2007. 相似文献
944.
Michael Gerharz MD ; Ankev Baranowsky PhD ; Udo Siebolts MD ; Sabine Eming MD ; Roswitha Nischt PhD ; Thomas Krieg PhD ; Claudia Wickenhauser MD 《Wound repair and regeneration》2007,15(1):105-112
Morphometric data based on skin wounding offer important information for the characterization of the phenotype of transgenic mouse models. The goal of this study was the comparison of technical procedures concerning wounding, processing, and evaluation of samples in different mouse strains. The multitissue array technique was used to estimate its adaptability for standardized analysis in wound healing. Skin wounds between days 1 and 14 after wounding were analyzed. The influence of mouse strain (C57BI/6 vs. FVB/N mice), sex, size of the punch biopsies, and preparation of the tissue sections was investigated on 94 mice. The parameters distance between the migration tongues (deltaMT) and surface not covered by epithelium were evaluated to describe the reepithelialization, and the distance between the adnexa was chosen to measure wound contraction. In addition, the techniques to measure the area of granulation tissue (GT) were evaluated. The data illustrate the requirement of standardized conditions for skin wound-healing experiments and demonstrate that histological preparation in serial sections is mandatory to detect slight differences in wound contraction. For the analysis of cellular composition in GT, multitissue arrays are useful tools in wound-healing studies. 相似文献
945.
Jan‐Ole Busch Michael Sticherling 《Journal der Deutschen Dermatologischen Gesellschaft》2007,5(10):no-no
The etiology of epidermolysis bullosa acquisita (EBA) is unknown. EBA may be associated with other autoim‐mune systemic diseases; it also has been described in connection with different malignant tumors, showing complete remission after successful treatment of the tumor.In such cases, EBA may be regarded as a paraneo‐plastic dermatosis. We detected a highly differentiated neuroendocrine pancreatic cancer in a 78‐year‐old woman with EBA. Even thought her tumor was completely removed and the patient has been disease‐free for over seven years, a complete regression of her autoimmune bullous dermatosis could not be induced. By using intravenous immunoglobulins in combination with mycophenolate mofetil, further blister formation could be ameliorated. 相似文献
946.
947.
Prof. Dr. Bernhard Schmitt Prof. Dr. Michael Albani Priv.-Doz. Dr. Thomas Bast Prof. Dr. Ulrich Brandl Prof. Dr. Rudolf Korinthenberg Prof. Dr. Gerhard Kurlemann Prof. Dr. Bernd Neubauer Prof. Dr. Ulrich Stephani Dr. Markus Wolff 《Zeitschrift für Epileptologie》2007,20(3):113-119
Zusammenfassung
Der richtige Zeitpunkt für das Absetzen der Antiepileptika (AE) im Kindesalter ist unbekannt. Anl?sslich ihrer Jahrestagung
haben die Mitglieder des K?nigsteiner Arbeitskreises (KA) eigene und publizierte Absetzstrategien diskutiert. Da Studien zu
diesem Thema rar und widersprüchlich sind, wurde beschlossen, die Diskussionsergebnisse im Sinne einer Meinungs?u?erung zu
publizieren.
Bei Neugeborenen besteht übereinstimmung, AE innerhalb von 2 bis 12 Wochen nach dem letzten Anfall abzusetzen. Bei BNS-Epilepsie
wird Vigabatrin nach 6 bis 12 und Sultiam nach 6 bis 36 Monaten abgesetzt. Nach erfolgreicher Steroidtherapie setzt die Mehrheit
des KA die AE-Therapie für zwei Jahre fort. Für die Rolando-Epilepsie sind 1 bis 3 Jahre Anfallsfreiheit ausreichend, auch
wenn fokale Spike-Waves persistieren. Im Falle einer symptomatisch fokalen Epilepsie ist die Grunderkrankung mitentscheidend
für das Absetzen. Die Behandlung der Absencen-Epilepsie kann nach zwei Jahren beendet werden, w?hrend bei myoklonisch- astatischer
Epilepsie meist eine 2- bis 5-j?hrige Anfallsfreiheit vorausgesetzt wird. Konsens besteht darüber, dass die Juvenile- Myoklonus-Epilepsie
ein sehr hohes Rückfallrisiko birgt. Dennoch ziehen einzelne neurop?diatrische Mitglieder einen Absetzversuch nach 2- bis
3-j?hriger Anfallsfreiheit in Betracht. Die überwiegende Mehrheit des KA führt aber bei gesicherter Diagnose keinen Absetzversuch
durch. Bezüglich der Absetzgeschwindigkeit wird ein langsames (3 bis 12 Monate) Ausschleichen favorisiert. Nur zwei Mitglieder
praktizieren ein rascheres Absetzen (<3 Monaten). Das EEG spielt für die Entscheidung eine untergeordnete Rolle und bleibt
auf bestimmte Epilepsieformen (z. B. Absencen-Epilepsie) beschr?nkt.
Das vorliegende Papier gibt die Meinung des KA wieder und eignet sich nicht im Sinne einer Leitlinie. Für die Entscheidung
AE abzusetzen, ist immer eine individuelle Abw?gung von Grunderkrankung, Epilepsieform und psychosozialen Umst?nde erforderlich.
相似文献
948.
Peter R Loewenson Marjorie Ireland Michael D Resnick 《The Journal of adolescent health》2004,34(3):209-215
PURPOSE: To assess reasons for choosing not to have sexual intercourse among two groups: virgins (primary abstainers) and already sexually experienced youth (secondary abstainers). METHODS: 73,464 Minnesota ninth- and twelfth-grade adolescents completed the 1998 Minnesota Student Survey. Respondents identified reasons for abstinence from a checklist from which they could nominate all relevant items. Reasons for each group were analyzed using Chi-square with a conservative criterion value (p <.001) owing to large sample size. Logistic regression was used to examine the associations of gender, grade, and their interactions, with reasons for abstinence. RESULTS: Sixty-six percent reported never having had intercourse (primary abstainers). Among sexually experienced youth, 7.8% reported choosing not to have intercourse (secondary abstainers). Fear of pregnancy was the reason endorsed most often, more by girls than by boys (OR = 26 for primary abstainers, 6.9 for secondary abstainers). Fear of other adverse consequences, such as sexually transmitted infections, parental disapproval, or fear of getting caught, were generally selected by more girls than boys, and by more primary than secondary abstainers. Similarly, more girls and primary abstainers than boys or secondary abstainers generally selected statements reflecting normative beliefs on youth or their friends having intercourse. CONCLUSIONS: Fear of adverse consequences and normative beliefs about the appropriateness of having sexual intercourse were most frequently endorsed as important reasons by both groups of abstainers. 相似文献
949.
Jennifer R. Ellsworth Michael J. Lambert Jennifer Johnson 《Clinical psychology & psychotherapy》2006,13(6):380-391
Recent research has found that measuring, monitoring and providing therapists with feedback about their clients' treatment progress improves treatment outcome. This study assessed the level of agreement between two outcome measures used to measure and monitor treatment progress. The Outcome Questionnaire (OQ‐45) was compared with a shorter, derivative measure, the OQ‐30. Each measure has an associated feedback system, which provides therapists with feedback about their clients' treatment progress. The OQ‐45 and the OQ‐30 demonstrated high levels of agreement in measurement of client outcome. The OQ‐45 feedback system emerged as the most accurate and clinically useful method for providing therapists with feedback about their clients' predicted treatment outcomes. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
950.
Comparison of risk stratification with pharmacologic and exercise stress myocardial perfusion imaging: A meta-analysis 总被引:2,自引:0,他引:2
Navare Sachin M. Mather Jeff F. Shaw Leslee J. Fowler Michael S. Heller Gary V. 《Journal of nuclear cardiology》2004,11(5):551-561
BACKGROUND: Although pharmacologic stress myocardial perfusion imaging (MPI) and exercise stress MPI have comparable diagnostic accuracy, their comparative value for risk stratification of patients with known or suspected coronary disease is not known. METHODS AND RESULTS: The data of 14,918 patients were combined from 24 studies evaluating prognosis in patients undergoing either pharmacologic stress or exercise stress MPI. Studies were included if a 2 x 2 table for hard cardiac events (cardiac death and myocardial infarction [MI]) could be constructed from the data available. Excluded were studies performed for post-MI, post-revascularization, or preoperative risk stratification. A weighted t test was used to compare the cardiac events, and a random effects model was used to calculate summary odds ratios. Summary odds ratios for hard cardiac events were similar for pharmacologic stress and exercise stress MPI. Summary receiver operating characteristic curves also showed no difference in discriminatory power between the stressors. The cardiac event rates were significantly higher with normal and abnormal test results with pharmacologic stress MPI than with exercise stress MPI (1.78% vs 0.65% [P < .001] for normal results and 9.98% vs 4.3% [P < .001] for abnormal results). Subgroup analysis revealed that both cardiac death and nonfatal MI were significantly higher with pharmacologic stress MPI. Patients undergoing pharmacologic stress MPI had a significantly higher prevalence of poor prognostic factors, and meta-regression revealed that exercise capacity was the single most important predictor of cardiac events. CONCLUSIONS: This meta-analysis shows that exercise stress MPI and pharmacologic stress MPI are comparable in their ability to risk-stratify patients. However, patients undergoing pharmacologic stress studies are at a higher risk for subsequent cardiac events. This is true even for those with normal perfusion imaging results. 相似文献