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   2219篇
  免费   168篇
  国内免费   2篇
耳鼻咽喉   22篇
儿科学   126篇
妇产科学   101篇
基础医学   270篇
口腔科学   48篇
临床医学   184篇
内科学   446篇
皮肤病学   70篇
神经病学   166篇
特种医学   56篇
外科学   221篇
综合类   55篇
一般理论   1篇
预防医学   144篇
眼科学   84篇
药学   190篇
中国医学   24篇
肿瘤学   181篇
  2023年   27篇
  2022年   59篇
  2021年   92篇
  2020年   79篇
  2019年   104篇
  2018年   125篇
  2017年   84篇
  2016年   123篇
  2015年   102篇
  2014年   124篇
  2013年   141篇
  2012年   191篇
  2011年   184篇
  2010年   94篇
  2009年   80篇
  2008年   103篇
  2007年   128篇
  2006年   105篇
  2005年   66篇
  2004年   48篇
  2003年   36篇
  2002年   21篇
  2001年   28篇
  2000年   23篇
  1999年   23篇
  1998年   10篇
  1992年   15篇
  1991年   15篇
  1990年   8篇
  1989年   14篇
  1988年   10篇
  1987年   8篇
  1986年   4篇
  1985年   8篇
  1984年   11篇
  1983年   6篇
  1982年   3篇
  1981年   3篇
  1980年   5篇
  1978年   3篇
  1977年   3篇
  1974年   10篇
  1973年   10篇
  1972年   4篇
  1971年   7篇
  1970年   3篇
  1969年   3篇
  1968年   5篇
  1967年   4篇
  1966年   6篇
排序方式: 共有2389条查询结果,搜索用时 15 毫秒
1.

Background

Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA.

Methods

We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year.

Results

Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time.

Conclusion

In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room.  相似文献   
2.
Cornual, interstitial, and angular pregnancies are terms that are often used interchangeably in both the literature and clinical setting to describe various ectopic pregnancies. The diagnosis of these pregnancies can be difficult, and fear of disrupting an intrauterine pregnancy can cause hesitation during evaluation and management. In our 2 cases, a combination of transvaginal and 3-dimensional ultrasound images provided assistance in the accurate diagnosis of angular ectopic pregnancies. Traditional management of these pregnancies includes a wedge resection for pregnancy resolution. In this set of 2 cases, we describe a unique surgical approach to resolve these pregnancies using operative hysteroscopy.  相似文献   
3.
4.
5.
OBJECTIVE: The combination of mifepristone and misoprostol is an established method for induction of early first trimester abortion, but there is no consensus about the best evaluation of treatment outcome. We assessed endometrial thickness, determined by ultrasound and serum-human chorionic gonadotropin (s-hCG) as markers of successful management. METHODS: Prospective trial involving 255 women, with a gestation of 62 days or less, who were to undergo medical abortion. In addition to our established routines of performing clinical and ultrasound examinations, we also determined the s-hCG level prior to treatment and at follow-up. RESULTS: Of the 255 subjects treated during the study, 20 (7.8%) were lost to follow-up. The overall complete abortion rate was 94.0%. Fourteen subjects required vacuum aspiration, nine of them prior to the scheduled follow-up and five thereafter. None of the pregnancies were ongoing. A decrease of 99% in s-hCG levels was noted in 99% of the women, when levels determined prior to mifepristone intake and those measured 15-71 days post-abortion were compared. CONCLUSION: This study confirms that s-hCG levels drop sharply after medical abortion. To assess the completeness of medical abortion, we recommend that clinical examination to be combined with determination of s-hCG. Ultrasonography should be carried out only when indicated.  相似文献   
6.
7.
Premature ovarian failure   总被引:9,自引:0,他引:9  
Premature ovarian failure (POF) causing hypergonadotrophic hypogonadism occurs in 1% of women. In majority of cases the underlying cause is not identified. The known causes include: (a) Genetic aberrations, which could involve the X chromosome or autosomes. A large number of genes have been screened as candidates for causing POF; however, few clear causal mutations have been identified. (b) Autoimmune ovarian damage, as suggested by the observed association of POF with other autoimmune disorders. Anti-ovarian antibodies are reported in POF by several studies, but their specificity and pathogenic role are questionable. (c) Iatrogenic following surgical, radiotherapeutic or chemotherapeutic interventions as in malignancies. (d) Environmental factors like viral infections and toxins for whom no clear mechanism is known. The diagnosis is based on finding of amenorrhoea before age 40 associated with FSH levels in the menopausal range. Screening for associated autoimmune disorders and karyotyping, particularly in early onset disease, constitute part of the diagnostic work-up. There is no role of ovarian biopsy or ultrasound in making the diagnosis. Management essentially involves hormone replacement and infertility treatment, the only proven means for the latter being assisted conception with donated oocytes. Embryo cryopreservation, ovarian tissue cryopreservation and oocyte cryopreservation hold promise in cases where ovarian failure is foreseeable as in women undergoing cancer treatments.  相似文献   
8.
Zygomycosis is an emerging infection worldwide. A study was conducted to understand its spectrum in the Indian scenario. All patients diagnosed for invasive zygomycosis at a tertiary care center in north India from 2000-2004, were retrospectively analyzed. A total of 178 cases (mean average of 35.6 cases/year) of zygomycosis were diagnosed. Rhino-orbito-cerebral type (54.5%) was the commonest presentation followed by cutaneous (14.6%), disseminated (9.0%), and gastrointestinal (8.4%) zygomycosis. Renal and pulmonary zygomycosis were seen in 6.7% patients each. Uncontrolled diabetes mellitus (in 73.6% of cases) was the significant risk factor in all types (Odds Ratio 1.5-8.0) except renal zygomycosis. Breach of skin was the risk factor in 46.2% patients with cutaneous zygomycosis. However, no risk factor could be detected in 11.8% patients. Antemortem diagnosis was possible in 83.7% cases. The commonest (61.5%) isolate was Rhizopus oryzae followed by Apophysomyces elegans in 27% patients. Combination of debridement surgery and amphotericin B therapy was significantly better in survival of the patients (P<0.005) than amphotericin B alone (79.6% vs. 51.7% survival). Thus, a rising trend of invasive zygomycosis was observed in patients with uncontrolled diabetes mellitus in India. Consistent diagnosis of renal zygomycosis in apparently healthy hosts and the emergence of A. elegans in India demand further study.  相似文献   
9.
10.
Diagnosis of post-kala-azar dermal leishmaniasis (PKDL), caused by Leishmania donovani, is difficult, as the dermal lesions are of several types and resemble those caused by other skin diseases, especially leprosy. Since the disease generally appears very late after the clinical cure of kala-azar in India, it is also difficult to correlate PKDL with a previous exposure to L. donovani. Very few attempts have been made so far to diagnose PKDL serologically, and the diagnostic methods vary in their sensitivities and specificities. Diagnosis of PKDL through sophisticated PCR methods, although highly sensitive, has limited practical use. We have developed a serodiagnostic method using an enzyme-linked immunosorbent assay to detect specific immunoglobulin (Ig) isotypes and IgG subclass antibodies in the sera of Indian PKDL patients. Our assay, which uses L. donovani promastigote membrane antigens, was 100% sensitive for the detection of IgG and 96.7% specific for the detection of IgG and IgG1. Optical density values for individual patients, however, demonstrated wide variations. Western blot analysis based on IgG reactivity could differentiate patients with PKDL from control subjects, which included patients with leprosy, patients from areas where kala-azar is endemic, and healthy subjects, by the detection of polypeptides of 67, 72, and 120 kDa. The recognition patterns of the majority of serum samples from patients with PKDL were also distinct from those of the serum samples from patients with visceral leishmaniasis (VL), at least for a 31-kDa polypeptide. To further differentiate patients with PKDL from those with active and cured VL, we analyzed the specific titers of the Ig isotypes and IgG subclasses. High levels of IgG, IgG1, IgG2, and IgG3 antibodies significantly differentiated patients with PKDL from patients cured of VL. The absence of antileishmanial IgE and IgG4 in patients with PKDL differentiated these patients from those with active VL. These results imply intrinsic differences in the antibodies generated in the sera from patients with PKDL and VL.  相似文献   
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