首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1336201篇
  免费   94345篇
  国内免费   2908篇
耳鼻咽喉   19714篇
儿科学   40238篇
妇产科学   38690篇
基础医学   187261篇
口腔科学   39829篇
临床医学   112648篇
内科学   262414篇
皮肤病学   30211篇
神经病学   106376篇
特种医学   53668篇
外国民族医学   435篇
外科学   208240篇
综合类   31047篇
现状与发展   6篇
一般理论   436篇
预防医学   92181篇
眼科学   31363篇
药学   100070篇
  4篇
中国医学   2988篇
肿瘤学   75635篇
  2018年   11741篇
  2015年   11880篇
  2014年   16689篇
  2013年   25256篇
  2012年   33004篇
  2011年   34884篇
  2010年   20734篇
  2009年   20231篇
  2008年   33583篇
  2007年   36693篇
  2006年   37267篇
  2005年   36020篇
  2004年   35093篇
  2003年   34071篇
  2002年   33600篇
  2001年   63629篇
  2000年   65334篇
  1999年   55397篇
  1998年   14654篇
  1997年   13464篇
  1996年   12940篇
  1995年   12226篇
  1994年   11472篇
  1992年   42774篇
  1991年   41290篇
  1990年   40564篇
  1989年   39565篇
  1988年   36973篇
  1987年   36421篇
  1986年   34903篇
  1985年   33108篇
  1984年   24829篇
  1983年   21057篇
  1982年   12670篇
  1981年   11571篇
  1980年   10778篇
  1979年   23930篇
  1978年   17071篇
  1977年   14837篇
  1976年   13388篇
  1975年   15271篇
  1974年   18091篇
  1973年   17562篇
  1972年   16814篇
  1971年   15721篇
  1970年   14917篇
  1969年   14351篇
  1968年   13463篇
  1967年   12017篇
  1966年   11262篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
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   
992.
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   
993.
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   
994.
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   
995.
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   
996.
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   
997.
998.
999.
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号