全文获取类型
收费全文 | 1342831篇 |
免费 | 94862篇 |
国内免费 | 2921篇 |
专业分类
耳鼻咽喉 | 19795篇 |
儿科学 | 40438篇 |
妇产科学 | 38781篇 |
基础医学 | 188175篇 |
口腔科学 | 39966篇 |
临床医学 | 113616篇 |
内科学 | 263566篇 |
皮肤病学 | 30277篇 |
神经病学 | 107057篇 |
特种医学 | 53977篇 |
外国民族医学 | 435篇 |
外科学 | 209010篇 |
综合类 | 31134篇 |
现状与发展 | 7篇 |
一般理论 | 443篇 |
预防医学 | 92819篇 |
眼科学 | 31473篇 |
药学 | 100598篇 |
4篇 | |
中国医学 | 3022篇 |
肿瘤学 | 76021篇 |
出版年
2018年 | 11852篇 |
2015年 | 12025篇 |
2014年 | 16881篇 |
2013年 | 25545篇 |
2012年 | 33428篇 |
2011年 | 35297篇 |
2010年 | 20965篇 |
2009年 | 20475篇 |
2008年 | 33955篇 |
2007年 | 37119篇 |
2006年 | 37681篇 |
2005年 | 36463篇 |
2004年 | 35570篇 |
2003年 | 34519篇 |
2002年 | 33969篇 |
2001年 | 63715篇 |
2000年 | 65399篇 |
1999年 | 55481篇 |
1998年 | 14739篇 |
1997年 | 13540篇 |
1996年 | 12998篇 |
1995年 | 12292篇 |
1994年 | 11537篇 |
1992年 | 42829篇 |
1991年 | 41347篇 |
1990年 | 40620篇 |
1989年 | 39616篇 |
1988年 | 37022篇 |
1987年 | 36465篇 |
1986年 | 34955篇 |
1985年 | 33156篇 |
1984年 | 24878篇 |
1983年 | 21101篇 |
1982年 | 12714篇 |
1981年 | 11613篇 |
1980年 | 10822篇 |
1979年 | 23954篇 |
1978年 | 17093篇 |
1977年 | 14861篇 |
1976年 | 13429篇 |
1975年 | 15296篇 |
1974年 | 18108篇 |
1973年 | 17593篇 |
1972年 | 16833篇 |
1971年 | 15737篇 |
1970年 | 14931篇 |
1969年 | 14364篇 |
1968年 | 13471篇 |
1967年 | 12023篇 |
1966年 | 11277篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
T Y Tang S R Walsh J H Gillard K Varty J R Boyle M E Gaunt 《European journal of vascular and endovascular surgery》2007,34(3):304-311
OBJECTIVES: Local anaesthetic infiltration into the carotid sinus during carotid endarterectomy (CEA) has been recommended to minimise blood pressure fluctuations but its use remains controversial. The aim of this meta-analysis was to determine whether intra-operative administration of local anaesthetic reduces the incidence of haemodynamic instability following CEA. MATERIALS AND METHODS: A search of the Medline, Pubmed and Embase databases and the Current Controlled Trials register identified four trials, which met the pre-defined inclusion criteria for data extraction. Pooled odds ratios with 95 per cent confidence intervals (c.i.) for the development of post-operative hypotension and hypertension were calculated using a random-effects model. RESULTS: Outcomes of 432 patients were studied. Local anaesthetic blockade of the carotid sinus was associated with a pooled odds ratio of 1.25 (95 per cent c.i. 0.496 to 3.15); p=0.216) and 1.28 (95 per cent c.i. 0.699 to 2.33; p=0.428) for the development of post-operative hypotension and hypertension respectively. Although none reach significance there was a trend towards increased risk of developing a complication in those patients who received local anaesthetic. CONCLUSIONS: There are insufficient data to determine the role of intra-operative local anaesthetic administration in reducing post-operative blood pressure lability following CEA. Conversely, the possibility of harm cannot be excluded on the basis of the currently available data. 相似文献
992.
By oxygen concentration measurements (Oximeter Oxydig Dräger, Lübeck) in the EC 145 helicopter two oxygen transport and application systems were compared. The new liquid oxygen system (LOX) for the oxygen therapy was assessed in an application observation. For physical reasons fluid oxygen evaporates during the stand-by phase and an increased concentration (22.8% O2) in the exhaust valve of LOX arises. On the other hand a high oxygen concentration (22.7% O2) was measured in the operation mode of the conventional pressure flask gas system (GAS). No increased concentration could be measured within the helicopter cabin (HEMS, PAX) comparing both oxygen systems. For transport and application of oxygen with a very big reserve for the air dependent intensive transport the results show that LOX is a sure low pressure system (3.4 bar). 相似文献
993.
994.
The enormous development in the field of molecular genetics during the last decades has lead to optimism concerning the possibilities for identifying the causes of multiple sclerosis (MS) through genetic studies. However, we have learned that dense mapping of large sample sets is needed, which only can be achieved through large collaborative studies. The contribution from each yet unidentified gene is probably weaker than that of the well established human leukocyte antigen association. The ultimate goal of the search for susceptibility genes in MS is to develop diagnostic tools and better treatments that can prevent or reduce the development of symptoms of this often devastating disease. 相似文献
995.
Charles H Henry Judith A Whittum-Hudson Gregory T Tull Larry M Wolford 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(1):e22-e26
OBJECTIVE: The objective of this study was to determine if temporomandibular joint (TMJ) samples positive for Chlamydia trachomatis have a greater presence of tumor necrosis factor-alpha (TNFalpha) or interleukin-6 (IL-6) when compared with Chlamydia-negative samples. STUDY DESIGN: Posterior bilaminar tissue samples removed during TMJ surgery from 70 patients were evaluated. Cryosections were stained using monoclonal antibody that identifies C. trachomatis. The presence of IL-6 and TNFalpha were evaluated by immunostaining in 15 samples positive and in 25 samples negative for the presence of C. trachomatis. RESULTS: Of the 70 TMJ samples, 32 (46%) were positive for C. trachomatis. In 15 samples positive for C. trachomatis, 10 (67%) were positive for TNFalpha and 7 (47%) for IL-6. In 25 samples negative for C. trachomatis, only 4 (16%) were positive for TNFalpha and only 2 (8%) for IL-6. Differences in C. trachomatis-positive samples versus negative were significant for both TNFalpha (P < .002) and IL-6 (P < .008). CONCLUSION: The presence of C. trachomatis in the TMJ is associated with a significantly increased presence of TNFalpha and IL-6. 相似文献
996.
Tendon injuries of the hand, especially flexor tendon injuries, should be treated by specially trained surgeons. Tendon injuries should be treated immediately to avoid joint stiffness or tendon adhesions, which arise predominantly at the tendon laceration. In addition to a professional operation, postoperative management is also important. As with surgery, specially trained physiotherapists should supervise the active or passive mobilization after tendon repair. A close cooperation between physiotherapist and physician is mandatory for an optimal result. 相似文献
997.
Dr. A.P. Anastasiadis H. Joneidi-Jafari T. Fehmer G. Muhr T. Kälicke 《Trauma und Berufskrankheit》2007,9(3):208-211
Isolated fractures of the metacarpal and phalangeal bones are common injuries of the upper extremities. They usually occur at the age of 10–40, whereas the highest incidence is observed in childhood. The results of treatment have an important impact for the practical value of the hand. This article aims to give a brief overview of the different fracture types and their treatment options. 相似文献
998.
Objective To describe the clinical presentation of acute diverticulitis in an emergency department and to characterize the natural history of diverticulitis in the short perspective. Comparisons are made with an important differential diagnosis, nonspecific abdominal pain (NSAP). Method Patients admitted to our hospital with abdominal pain of up to 7 days’ duration were registered prospectively using a detailed schedule for history, symptoms and signs, from 1 February 1997 to 1 June 2000. Of 3349 patients initially included, 3073 (92%) were eligible for follow up after 1–3 years. Results Acute diverticulitis was the final diagnosis in 145 patients and NSAP in 1142 patients. The incidence of hospitalized patients with diverticulitis was 47 per year and 100 000 population, with a mean hospital stay of 3.3 days. Patients with diverticulitis, more frequently than NSAP, had a longer history and laboratory signs of inflammatory activity. Isolated left abdominal tenderness was more common in diverticulitis, whereas isolated right abdominal tenderness was more common in NSAP. Duration of symptoms on arrival was independent of age and was not correlated to C‐reactive protein, leucocytes or body temperature. Sensitivity of diverticulitis as primary diagnosis was 64% and specificity 97%. Corresponding figures for NSAP were 43% and 90% respectively. Age and gender did not influence diagnostic accuracy or risk of surgery. Conclusion Diverticulitis differs significantly from NSAP in clinical presentation and laboratory parameters. Sensitivity of primary diagnosis for diverticulitis and NSAP was low. 相似文献
999.
H. S. Pollinger M. D. Stegall J. M. Gloor S. B. Moore S. R. Degoey N. A. Ploeger W. D. Park H. S. Pollinger M. D. Stegall J. M. Gloor S. B. Moore S. R. Degoey N. A. Ploeger W. D. Park 《American journal of transplantation》2007,7(4):857-863
The immunologic risk associated with donor-specific antibodies (DSA) against Class II human leukocyte antigens (HLA) in kidney transplant (KTx) recipients is unclear. The aim of this study was to determine the outcome of KTx when DSA was detected only against HLA Class II. To isolate the impact of anti-Class II DSA, we retrospectively analyzed 12 KTx recipients who at baseline had a positive B-cell flow cytometric crossmatch (FXM) and a negative T-cell FXM. Using alloantibody specification analysis, 58.3% (7/12) had DSA against donor Class II and 41.7% had no demonstrable DSA. Biopsy-proven AMR occurred in 57% (4/7) in the Class II(+) group and 0% in the Class II(-) group (p > 0.05). Peritubular capillaries stained positive for C4d in 86% (6/7) of the Class II(+) patients and in 40% (2/5) of the Class II(-) patients (p > 0.05). One patient in the Class II(+) group lost their graft at 3 months to accelerated transplant glomerulopathy, while all other grafts were functioning 3-37 months posttransplant despite the persistence of anti-Class II DSA. We conclude that KTx recipients with clearly defined anti-Class II DSA are at risk for humoral rejection suggesting that desensitization and/or close posttransplant monitoring may be needed to prevent AMR. 相似文献
1000.
C Cote M D Zilberberg S H Mody L J Dordelly B Celli 《The European respiratory journal》2007,29(5):923-929
Haemoglobin (Hb) abnormalities in chronic obstructive pulmonary disease (COPD) are not well characterised. The present authors investigated the prevalence and association of abnormal Hb with clinical outcomes. Analysis of a prospective cohort of stable COPD outpatients (n = 683) in a USA Veterans Administration pulmonary clinic was undertaken. Patients were classified as anaemic (Hb <13 g.dL(-1)), polycythemic (Hb > or =17 g.dL(-1) and > or =15 g.dL(-1) for males and females, respectively) or normal. Demographic characteristics and physiological/functional outcomes were compared between groups. Regression models adjusting for confounders examined the independent association of anaemia with clinical outcomes. Anaemia was present in 116 (17%) patients and polycythemia in 40 (6%). While the only values that differed between polycythemic and nonpolycythemic patients were mean body mass index and Hb, anaemic patients showed a significantly higher modified Medical Research Council dyspnoea scale score (2.8 versus 2.6), lower 6-min walk distance (265 versus 325 m) and shorter median survival (49 versus 74 months) than nonanaemic patients. In regression models, anaemia independently predicted dyspnoea and reduced exercise capacity. Anaemia in chronic obstructive pulmonary disease was an independent risk factor for reduced functional capacity. Polycythemia prevalence was low and had no association with worsened outcomes. Further work is required to evaluate the effect of anaemia correction on outcomes in chronic obstructive pulmonary disease. 相似文献