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   12070篇
  免费   772篇
  国内免费   88篇
耳鼻咽喉   137篇
儿科学   314篇
妇产科学   358篇
基础医学   1416篇
口腔科学   334篇
临床医学   979篇
内科学   2788篇
皮肤病学   219篇
神经病学   548篇
特种医学   363篇
外国民族医学   2篇
外科学   1893篇
综合类   334篇
一般理论   8篇
预防医学   786篇
眼科学   487篇
药学   1111篇
中国医学   128篇
肿瘤学   725篇
  2023年   137篇
  2022年   300篇
  2021年   574篇
  2020年   362篇
  2019年   492篇
  2018年   515篇
  2017年   374篇
  2016年   356篇
  2015年   331篇
  2014年   530篇
  2013年   622篇
  2012年   918篇
  2011年   919篇
  2010年   530篇
  2009年   417篇
  2008年   668篇
  2007年   701篇
  2006年   569篇
  2005年   535篇
  2004年   514篇
  2003年   423篇
  2002年   375篇
  2001年   164篇
  2000年   165篇
  1999年   156篇
  1998年   74篇
  1997年   43篇
  1996年   52篇
  1995年   53篇
  1994年   56篇
  1993年   36篇
  1992年   73篇
  1991年   73篇
  1990年   89篇
  1989年   71篇
  1988年   69篇
  1987年   71篇
  1986年   76篇
  1985年   50篇
  1984年   43篇
  1983年   28篇
  1982年   26篇
  1981年   17篇
  1980年   24篇
  1979年   31篇
  1977年   28篇
  1976年   23篇
  1974年   16篇
  1973年   17篇
  1970年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Background. Primary adenocarcinoma of the larynx is a rare neoplasm. The incidence is reported as less than 1% of all laryngeal neoplasms in multiple series. Simultaneous primary adenocarcinoma and a solitary squamous cell carcinoma of the larynx is even rarer and only one case has been found on review of the literature. Methods. A case report of a 74-year-old man with a history of right-sided throat pain, odynophagia, and progressive hoarseness is presented with a review of the literature pertaining to this unusual case. Results. The patient was found to have three distinctly separate laryngeal lesions on direct laryngoscopy. Histopathologic diagnosis of adenocarcinoma was made on one of the three biopsied sites with the other sites being squamous cell carcinoma. Following Combined radiotherapy and surgical treatment, the patient has remained free of disease. Conclusions. Adenocarcinoma of the larynx is an infrequent and lethal disease. This case report and a review of the literature demonstrate that aggressive surgical management is indicated, although still may not result in improved survival. © 1994 John Wiley & Sons, Inc.  相似文献   
42.
Ultrasound examination in 8 patients with occlusive jaundice demonstrated non-lithiasic extrahepatic intracanalar obstacles, a malignant tumor in 4 and a non-tumoral process (granuloma on suture thread, ball sludge, hemobilia in 2 cases) in the other 4. Analysis of echographic data suggested possible differential diagnosis criteria for these two types of occlusion.  相似文献   
43.
Most pediatric cochlear implant programs support a team approach for post-implant services. However, individuals directly involved in the care of these children often have differing opinions on the child's performance. We describe our experience with four children, aged 3 to 10 at the time of implantation, who have used the Nucleus 22-channel cochlear implant device for at least nine months. A questionnaire, focusing on the individual's observations of the child's speech and hearing performance in their particular setting (i.e., clinic, home, school), was completed by the child's parent(s), therapist and classroom teacher. Overall, performance in structured settings (i.e., testing and therapy sessions) was not in agreement with performance in unstructured settings (i.e., classroom and home environments). The results suggest that different individuals interacting with the same child in different environments often have differing perceptions of the child's performance. Based on the information obtained on the four cases, we discuss factors to consider in assessing the real-life performance of pediatric cochlear implant recipients.  相似文献   
44.
We reviewed data from 47 patients who were treated for endophthalmitis at our hospital during the 11-year period 1980-90. The most common clinical features were hypopyon (75%), diminished vision (72%), ocular pain (68%), discharge (57%), corneal oedema (51%), conjunctival injection (49%), abnormal red reflex (34%), corneal ulcer (32%) and corneal perforation (6%). A total of 54 isolates were obtained from 41 (87%) of the 47 patients. Gram-positive bacteria were more common (72%), than Gram-negative organisms (22%). Two cases were due to fungi, and herpes simplex virus was isolated from one case. The two most common Gram-positive organisms were coagulase-negative staphylococci (25%), and Staphylococcus aureus (11%), while Pseudomonas aeruginosa predominated among the Gram-negative bacteria isolated (15%). Mixed bacterial species were obtained from 29% of the infected patients, including one from whom Vibrio fluvialis was isolated. Predisposing factors included ocular surgery (60%)--mostly for cataract extraction (47%), penetrating trauma (15%) and periocular (15%) or systemic (11%) infections. All patients received antibiotics (generally chloramphenicol and/or a beta-lactamase-stable penicillin plus an aminoglycoside) prior to culture, when treatment was adjusted according to specific aetiological agents. Seventy-nine per cent of patients received topical or systemic steroids. Vitrectomy (diagnostic and therapeutic) was performed on 21% of patients. Sixty-three per cent of culture-positive patients lost vision (no perception of light) in the affected eye, compared to 17% of culture-negative cases (P < 0.05 Fisher exact test). Similarly, a better visual outcome (acuity of 6/12 or better) was associated with coagulase-negative staphylococcal infection than with streptococcal or fungal infections.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
45.
Several in vitro methods have been suggested to predict drug-induced haematotoxicity and species differences; the most commonly used being the clonogenic CFU-GM assay. The aim of the current study was to evaluate whether primary lymphocytes from peripheral blood, assayed with a short-term non-clonogenic assay, could be used to detect species differences in drug sensitivity, and offer an alternative to the CFU-GM assay. The effect of 17 different cytotoxic drugs on lymphocytes from human, dog, rat and mouse was evaluated. A higher sensitivity of human than mouse lymphocytes was seen for topotecan and for 3 of 5 antimetabolites tested. Clear species specificity was also seen for the proteasome inhibitor bortezomib where rodent cells were 50-300 times less sensitive than human cells. Good agreement between our data and published CFU-GM data was observed, suggesting that primary lymphocytes may be a useful model for species difference screening in drug development.  相似文献   
46.
Background  Reduced left ventricular ejection fraction (LVEF) is a risk factor for poor outcomes in patients with coronary artery disease (CAD). Mental stress-induced myocardial ischemia (MSIMI) also identifies a subset of CAD patients at increased risk for future cardiovascular events. Susceptibility to MSIMI in patients with CAD and reduced LVEF is unknown. Methods and Results  We enrolled 182 patients (67 women) with a mean age of 64 years and a documented history of CAD in this study. Baseline resting ejection fraction was determined by use of technetium 99m sestamibi gated single photon emission computed tomography. Abnormal LVEF was defined as less than 45% for men and less than 50% for women (based on published norms for our software [Cedars-Sinai Medical Center]). All participants underwent mental stress testing with a public speaking task. Rest/stress myocardial perfusion single photon emission computed tomography was performed via conventional methodology. Images were visually compared for number and severity of perfusion defects by use of a scoring method from 0 to 4. A summed difference score was calculated as the difference between summed stress and rest scores. A score of greater than 3 was considered abnormal. MSIMI developed in 19% of patients with normal LVEF and 31% of those with reduced LVEF. There is no statistically significant difference between the two groups (P=.11). Conclusions  CAD patients with left ventricular dysfunction are equally susceptible to MSIMI as those with normal LVEF. This study was supported by grants HL 070265 and HL 072059 from the National Heart. Lung, and Blood Institute. This material is also the result of work supported by resources and with the use of facilities at the Department of Veterans. Affairs Medical Center, Gainesville, Fla.  相似文献   
47.
BACKGROUND AND OBJECTIVES: Inguinal hernia repair is one of the most frequently performed pediatric surgical operations. Several pediatric laparoscopic inguinal hernia repair techniques have been introduced. But debate is unresolved regarding the feasibility of laparoscopy for treating pediatric inguinal hernias. METHODS: A retrospective cohort study enrolled 33 patients who underwent congenital inguinal hernia repair by either the new laparoscopic flip-flap technique or conventional open repair. Patients were divided into 2 groups according to the type of surgery: Group A included those who underwent the new laparoscopic technique, and Group B included those who underwent conventional open repair. RESULTS: Group A comprised 15 patients (mean age, 39 months), and group B comprised 18 (mean age, 44 months). Mean operative time was 47.5 minutes for Group A versus 27.5 minutes for Group B. Intraoperative complications for Group A included 1 case (7%) of vas deferens injury, and 3 cases (20%) in which the flaps were torn during suturing. In Group B, no intraoperative complications were encountered. In both groups, the mean postoperative hospital stay was 5.5 hours. Postoperative follow-up of 3 months revealed recurrence in 4 patients in Group A (27%), while there were no recurrences in Group B. CONCLUSION: Our preliminary experience shows unsatisfactory outcomes with laparoscopic flip-flap hernia repair in children. In spite of advancement in the application of laparoscopy in pediatric surgery, conventional open hernia repair is still the gold standard for children, in our experience. Future studies with more numbers and longterm follow-up should be conducted.  相似文献   
48.

Background  

While it is believed that total arterial grafting (TAG) for coronary artery bypass grafting (CABG) confers improved long-term outcomes when compared to conventional grafting with left internal mammary artery and saphenous vein grafts (LIMA+SVG), to date, this has not become the standard of care. In this study, we assessed the impact of TAG on medium-term outcomes after CABG.  相似文献   
49.
50.
Prednisone-Free Maintenance Immunosuppression—A 5-Year Experience   总被引:1,自引:0,他引:1  
Concern persists that prednisone-free maintenance immunosuppression in kidney transplant recipients will be associated with an increase in late allograft dysfunction and graft loss. We herein report 5-year follow-up of a trial of prednisone-free maintenance immunosuppression. From October 1, 1999, through January 31, 2005, at our center, 589 kidney transplant recipients were treated with a protocol incorporating discontinuation of their prednisone on postoperative day 6. At 5 years, actuarial patient survival was 91%; graft survival, 84%; death-censored graft survival, 92%; acute rejection-free graft survival, 84% and chronic rejection-free graft survival, 87%. The mean serum creatinine level (+/-SD) at 1 year was 1.6 +/- 0.6; at 5 years, 1.7 +/- 0.8. In all, 86% of kidney recipients with functioning grafts remain prednisone-free as of April 30, 2005. As compared with historical controls, recipients on prednisone-free maintenance immunosuppression had a significantly lower rate of a number of complications, including cataracts (p < 0.001), posttransplant diabetes mellitus (p < 0.001), avascular necrosis (p = 0.001), and fractures (p = 0.004). We conclude that prednisone-related side effects can be minimized in a protocol incorporating prednisone-free maintenance immunosuppression. Five-year graft outcome remains good.  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