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   9247篇
  免费   533篇
  国内免费   71篇
耳鼻咽喉   57篇
儿科学   204篇
妇产科学   133篇
基础医学   990篇
口腔科学   128篇
临床医学   990篇
内科学   2262篇
皮肤病学   150篇
神经病学   477篇
特种医学   235篇
外国民族医学   1篇
外科学   1720篇
综合类   250篇
现状与发展   1篇
一般理论   5篇
预防医学   560篇
眼科学   186篇
药学   838篇
中国医学   156篇
肿瘤学   508篇
  2024年   17篇
  2023年   179篇
  2022年   556篇
  2021年   705篇
  2020年   413篇
  2019年   499篇
  2018年   499篇
  2017年   296篇
  2016年   344篇
  2015年   371篇
  2014年   433篇
  2013年   521篇
  2012年   802篇
  2011年   748篇
  2010年   359篇
  2009年   330篇
  2008年   486篇
  2007年   466篇
  2006年   413篇
  2005年   372篇
  2004年   310篇
  2003年   288篇
  2002年   161篇
  2001年   48篇
  2000年   28篇
  1999年   24篇
  1998年   23篇
  1997年   12篇
  1996年   15篇
  1995年   11篇
  1994年   8篇
  1993年   13篇
  1992年   8篇
  1991年   7篇
  1990年   5篇
  1989年   5篇
  1988年   7篇
  1987年   3篇
  1985年   6篇
  1984年   8篇
  1983年   3篇
  1982年   7篇
  1981年   13篇
  1980年   4篇
  1978年   5篇
  1977年   4篇
  1976年   3篇
  1975年   2篇
  1972年   4篇
  1969年   2篇
排序方式: 共有9851条查询结果,搜索用时 15 毫秒
61.
Lower urinary tract dysfunction can have a significant impact on patients with spinal cord injury. Over the years, many treatment options have become available. This article reviews the assessment and management of neurogenic detrusor overactivity, with a particular focus on articles from the recent literature. Recent guidelines on the subject will be discussed. Management options include antimuscarinics and bladder emptying measures, botulinum toxin A, and neuromodulation in refractory cases and surgery for intractable cases. Recent and relevant publications in these areas will be summarized and discussed.  相似文献   
62.
The aim of this study was to evaluate the utility of donor-specific antibodies (DSA) and flow cytometry crossmatch (FCCM) as tools for predicting antibody-mediated rejection (AMR) in desensitized kidney recipients. Sera from 44 patients with DSA at the time of transplant were reviewed. Strength of DSA was determined by single antigen Luminex bead assay and expressed as mean fluorescence intensity (MFI). T- and B-cell FCCM results were expressed as mean channel shift (MCS). AMR was diagnosed by C4d deposition on biopsy. Incidence of early AMR was 31%. Significant differences in the number of DSAs (p = 0.0002), cumulative median MFI in DSA class I (p = 0.0004), and total (class I + class II) DSA (p < 0.0001) were found in patients with and without AMR. No significant difference was seen in MCS of T and B FCCM (p = 0.095 and p = 0.307, respectively). The three-yr graft survival in desensitized patients with DSA having total MFI < 9500 was 100% compared to 76% with those having total MFI > 9500 (p = 0.022). Desensitized kidney transplant recipients having higher levels of class I and total DSA MFI are at high risk for AMR and poor graft survival. Recipient DSA MFI appears to be a more reliable predictor of AMR than MCS of FCCM.  相似文献   
63.
Atrial myxomas are the most common benign tumors of the heart and are difficult to diagnose due to a wide variety of presenting symptoms. We present a patient with a five-year history of visual loss, vertigo, ataxia, tinnitus, and bone lesions that resolved after diagnosis and resection of an atrial myxoma. This case not only highlights an unusual presentation of atrial myxomas but also raises the question of whether atrial myxomas can produce paraneoplastic syndromes, including bone abnormalities.  相似文献   
64.

Study Objective

To apply ergonomic task analysis to the performance of ultrasound-guided (US-guided) femoral nerve block (FNB) in an acute hospital setting.

Design

Pilot prospective observational study.

Setting

Orthopedic operating room of a regional trauma hospital.

Subjects

15 anesthesiologists of various levels of experience in US-guided FNB (estimated minimum experience < 10 procedures; maximum about 50 procedures, and from basic trainees to consultants); and 15 patients (5 men and 10 women), aged 77 ± 15 (mean ± SD yrs) years.

Measurements/Observations

A data capture “tool”, which was modified from one previously developed for ergonomic study of spinal anesthesia, was studied. Patient, operator, and heterogeneous environmental factors related to ergonomic performance of US-guided FNB were identified. The observation period started immediately before commencement of positioning the patient and ended on completion of perineural injection. Data were acquired using direct observations, photography, and application of a questionnaire.

Main Results

The quality of ergonomic performance was generally suboptimal and varied greatly among operators. Eight (experience < 10 procedures) of 15 operators excessively rotated their head, neck, and/or back to visualize the image on the ultrasound machine. Eight operators (experience < 10 procedures) performed the procedure with excessive thoracolumbar flexion.

Conclusion

Performance of US-guided FNB presents ergonomic challenges and was suboptimal during most of the procedures observed. Formal training in US-guided peripheral nerve blockade should include reference to ergonomic factors.  相似文献   
65.
Human pluripotent embryonic stem cells (hESCs) have great promise for research into human developmental biology, development of cell therapies for the treatment of diseases, toxicology, and drug discovery. Traditionally, undifferentiated hESCs are maintained on mouse embryonic fibroblasts (MEFs), which impede the clinical applications of hESCs. Here we have examined the long-term stability of the Japanese hESC line (KhES-1) in feeder-free culture. KhES-1 cells were cultured with MEF conditioned medium (CM) and different doses of basic fibroblast growth factor (bFGF) in six-well-plates of which the surface was coated with Matrigel. KhES-1 cells were maintained for at least 40 passages. In this culture system, the cells maintained stable proliferation rates and steadily expressed Oct-4, Nanog, and alkaline phosphatase. In addition, KhES-1 cells maintained without direct feeder contact formed embryonic bodies with expression of markers from the three germ layers. Here we demonstrated that Japanese human embryonic stem cells KhES-1 were cultured long term in a feeder-free method, while retaining pluripotency in vitro.  相似文献   
66.
A young girl presented with history of prolonged fever, vomiting and headache. CT scan of brain revealed a space occupying lesion in posterior cranial fossa with moderate hydrocephalus. Surgery was performed and histopathology report confirmed the lesion as tuberculous. Patient showed smooth postoperative recovery and complete remission of complaints on antituberculous treatment for one year and regular follow-up.  相似文献   
67.
Objective: To determine the frequency of dual infection of Tuberculosis and Human Immunodeficiency Virus (HIV) and document the sexual practices of infected patients. Design: Cross-sectional study. Place and Duration of Study: Medical Unit-IV of Civil Hospital, Karachi, Pakistan, in collaboration with Sindh AIDS Control Program at Services Hospital, Karachi, from January 2003 to December 2004. Patients and Methods: Patients were recruited in the study at both centers and tested for both HIV and TB if any one disease was identified. Diagnosis of TB was based on positive sputum AFB smear / caseous granulomatous lesion on histopathology. Diagnosis of HIV was based on positive anti-HIV serology by LISA technique. A questionnaire was also administered to all the study participants regarding demographics, sexual practices, blood transfusion and intravenous drug abuse. Results: A total of 196 patients of HIV and TB were screened for the presence of dual infection (TB/HIV). Dual infection was present in 38 (19.39%) of patients. Out of 126 patients of HIV, evidence of TB was detected in 38 (30.16%). During the same duration, 70 patients of tuberculosis were screened for HIV and none was tested positive for HIV. History of illicit sexual relationship was found in 121 (96.03%) patients and 5 of these were homosexuals. Conclusion: Dual infection was present in patients of HIV with TB but vice versa was not documented in this study.  相似文献   
68.
This study examined the differences between full‐time self‐employed and organizationally employed individuals in Canada (n = 248) and Pakistan (n = 306) in terms of overall burnout and its three dimensions (emotional exhaustion, depersonalization and lack of accomplishment), turnover intentions and non‐work satisfaction. Data were collected by means of a structured questionnaire from Canadian employees in Montreal and Pakistani employees in Lahore. One‐way analysis of variance and multivariate analysis of variance were used to analyse the data. The self‐employed reported significantly higher overall burnout, emotional exhaustion, lack of accomplishment, non‐work satisfaction and turnover intention than the organizationally employed in both countries. No significant differences were found between self‐employed and organizationally employed in terms of depersonalization in both countries. Results are discussed in light of previous empirical evidence on self‐employment and the quality of work and non‐work life from cross‐cultural perspectives. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
69.
BACKGROUND: Mixed cryoglobulinemia (CG) is a systemic immune complex-mediated disease that involves small-to-medium vessel vasculitis, provoked by the CG containing immune complexes that precipitate in cold. It is associated with hepatitis C virus (HCV) infection in 80% of patients. Mixed CG-mediated vasculitis can affect vital organs such as kidney, liver and heart. Laboratory parameters show presence of cryoglobulin, and in most cases of mixed CG, rheumatoid factor IgM kappa. The current treatment strategy of HCV-associated CG includes targeting the viral trigger HCV with a combination of antiviral medication, interferon-alpha (IFN-alpha) and ribavirin, or the downstream pathogenic events by means of plasmapheresis, steroids or immunosuppression. With multiorgan involvement, the antiviral therapy may be limited due to severity of renal disease, treatment failure, side effects or contraindications. On the other hand, immunosuppressive therapy may be poorly tolerated or ineffective. Therefore, new treatment options such as rituximab (RIT), a chimeric monoclonal anti-CD20 antibody, have been proposed as a rescue therapy. METHODS: We reviewed the literature to evaluate the current evidence in treating HCV-related refractory mixed CG. RESULTS: The use of RIT in treatment of HCV-related CG was first described by Zaja et al. Since then there have been numerous published case series and case reports. So far there has been no randomized controlled trial. In the literature, there have been 60 patients with CG treated with RIT. The male to female ratio was 14:46. Fifty-three patients were HCV-positive. Forty-six patients had mixed type II CG, 7 had type III CG and for 7 the type was not specified. Twenty-five patients had renal involvement ranging from proteinuria, to nephrotic syndrome, to nephritic syndrome to chronic kidney disease. Eight patients had had a renal transplant and were on immunosuppression. Most patients responded to RIT, with only 17 of 60 patients relapsing, and 8 of 17 of those were rechallenged with RIT with a good response. Total follow-up period varied between 3 and 31 months. CONCLUSION: RIT is a suitable rescue therapy in recalcitrant CG associated with HCV. There is evidence supporting the use of RIT as first-line therapy, as opposed to the proposals of others who would strongly recommend antiviral therapy. However, a prospective randomized controlled trial is required to evaluate the efficacy and safety of RIT compared with current standard therapy, which includes antiviral therapy, immunosuppression and plasmapheresis.  相似文献   
70.

Background

Morbidity and mortality following laparoscopic sleeve gastrectomy (LSG) occur at acceptable rates, but its safety and efficacy in the elderly are unknown.

Methods

A retrospective review was performed of all patients aged >60 years who underwent LSG from 2008 to 2012. These patients were 1:2 matched, by gender and body mass index (BMI) to young patients, 18?<?age?<?50. Data analyzed included demographics, preoperative and postoperative BMI, postoperative complications, and improvement or resolution of obesity-related comorbidities.

Results

Fifty-two morbid obese patients older than 60 years underwent LSG (mean age, 62.9?±?0.3 years). These were matched to 104 young patients, age 18–50 years (mean age, 35.7?±?0.8 years). Groups did not differ in male gender (44 vs. 43 %, p?=?0.9), preoperative BMI (42.6?±?0.7 vs. 42.6?±?0.6, p?=?0.97), and length of follow-up (17?±?2 vs. 22?±?1.4 months, p?=?0.06). Obesity-related comorbidities were significantly higher in the older group (96 vs. 65 %, p?<?0.001). Excess weight loss (EWL) was higher in the younger group (75?±?2.4 vs. 62?±?3 %, p?=?0.001). Older patients had a significantly higher rate of a concurrent hiatal hernia repair (23 vs. 1.9 %, p?<?0.001). Overall postoperative minor complication rate was higher in the older group (25 vs. 4.8 %, p?<?0.001). This included atrial fibrillation (9.5 %), urinary tract infection (7 %), trocar site hernia (4 %), dysphagia, surgical site infection, bleeding, bowel obstruction, colitis, and nutritional deficiency (2 %, each). No perioperative mortality occurred. Comorbidity resolution or improvement was comparable between groups (88 vs. 80 %, p?=?0.13).

Conclusions

LSG is safe and very efficient in patients aged >60, despite higher rates of perioperative comorbidities.  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