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   5957篇
  免费   449篇
  国内免费   24篇
耳鼻咽喉   24篇
儿科学   194篇
妇产科学   157篇
基础医学   898篇
口腔科学   78篇
临床医学   653篇
内科学   1269篇
皮肤病学   106篇
神经病学   607篇
特种医学   225篇
外科学   691篇
综合类   55篇
一般理论   2篇
预防医学   588篇
眼科学   91篇
药学   432篇
中国医学   15篇
肿瘤学   345篇
  2024年   6篇
  2023年   78篇
  2022年   74篇
  2021年   235篇
  2020年   156篇
  2019年   209篇
  2018年   208篇
  2017年   157篇
  2016年   182篇
  2015年   195篇
  2014年   246篇
  2013年   313篇
  2012年   447篇
  2011年   475篇
  2010年   259篇
  2009年   217篇
  2008年   408篇
  2007年   374篇
  2006年   413篇
  2005年   346篇
  2004年   332篇
  2003年   308篇
  2002年   221篇
  2001年   58篇
  2000年   49篇
  1999年   54篇
  1998年   49篇
  1997年   38篇
  1996年   32篇
  1995年   48篇
  1994年   29篇
  1993年   12篇
  1992年   17篇
  1991年   16篇
  1990年   16篇
  1989年   21篇
  1988年   10篇
  1987年   9篇
  1986年   17篇
  1985年   9篇
  1984年   13篇
  1983年   12篇
  1982年   14篇
  1981年   4篇
  1980年   4篇
  1979年   8篇
  1977年   3篇
  1969年   3篇
  1967年   5篇
  1923年   2篇
排序方式: 共有6430条查询结果,搜索用时 15 毫秒
1.
2.
Risk is a concept inherent in every medical procedure. It can be defined as the probability of an adverse event in a defined population over a specified period of time. In the frame of food allergy management, it might be related to a diagnostic procedure, a treatment, or the consumption of foods. The risk of an adverse event can also be augmented by individual factors. This rostrum article discusses various aspects faced by children with food allergies in the light of risk, and their practical implications. Identifying personal risks for severe reaction, such as unstable asthma, and correcting them whenever possible also contribute to a reduction of the risk inherent to food allergy. Among the facets discussed, oral food challenges (OFC) are the most common diagnostic procedures implying an inherent risk. The risk of OFCs can be minimized by correct indication and timing of the test, a safe setting, as well as by ensuring that the patient is otherwise well without potential stressor potentially increasing the risk of a more severe reaction. Oral immunotherapy (OIT) has been studied as a potential treatment for increasing the threshold dose for reaction, and thus reducing the risk of accidental reaction. Nevertheless, the procedure is not devoid of risk as the patients may and do often react during the course of the procedure. Ingestion of trace amounts in processed foods, mainly in community settings such as restaurants, schools, or day care, represents a potential risk of reactions, although for a minority of patients. Precautionary allergen labeling (PAL) is a widespread strategy to reduce the potential risk of reactions due to traces. However, PAL is currently inefficient due to inconsistent labeling, also not indicating a clear maximum amount possibly present in the manufactured food. Finally, cost-effectiveness needs to be considered in risk management, as many risk reduction procedures are clearly not cost-effective.  相似文献   
3.

Background  

Although training and education have long been accepted as integral to disaster preparedness, many currently taught practices are neither evidence-based nor standardized. The need for effective evidence-based disaster training of healthcare staff at all levels, including the development of standards and guidelines for training in the multi-disciplinary health response to major events, has been designated by the disaster response community as a high priority. We describe the application of systematic evidence-based consensus building methods to derive educational competencies and objectives in criteria-based preparedness and response relevant to all hospital healthcare workers.  相似文献   
4.
PURPOSE: To analyze the effectiveness of surgery and chemotherapy with or without radiotherapy in the management of limited small cell lung cancer (LSCLC) in stages I and II. PATIENTS AND METHODS: 39 patients (median age 62 years) with LSCLC in stages pT1 or pT2 and pN0 or pN1 (stages IA-IIB) who had a tumor resection and systematic lymph node dissection were reviewed retrospectively. The median follow-up period was 29 months. 35 patients (90%) received a median of four cycles of a platinum-containing chemotherapy postoperatively. 16 patients (41%) received an adjuvant thoracic radiotherapy (TRT, median 50 Gy); 21 patients (54%) received a prophylactic cranial irradiation (PCI, median 30 Gy). RESULTS: The median overall survival for all patients was 47 months, resulting in actuarial 1-, 3-, and 5-year survival rates of 97%, 58%, and 49%, respectively. Distant metastases were found in 13 patients (33%) after a median of 16 months. Patients who received an adjuvant TRT showed a trend toward improved thoracic recurrence-free survival (p = 0.06) and improved overall survival (p = 0.07) compared to those treated with surgery and chemotherapy only. Brain metastasis-free survival (p = 0.01) and overall survival (p = 0.01) were improved significantly in patients who received a PCI. CONCLUSION: Surgical tumor resection may be considered for carefully selected patients. Adjuvant chemotherapy and PCI are recommended for all patients. Adjuvant TRT is currently used in patients with positive lymph nodes (pN1), because the probability of a subclinical involvement of the mediastinal lymphatic system appears to be increased in these patients.  相似文献   
5.
To determine whether polymorphisms of platelet surface glycoprotein associated with arterial thrombosis are risk factors for branch retinal vein occlusion. A case-control study in which 69 patients with branch retinal vein occlusion and 147 controls who attended the eye clinic for nonvascular complications participated. DNA was extracted from whole blood and analyzed for genotyping of platelet glycoprotein polymorphisms by polymerase chain reactions and specific restricted enzymes. No relationship was found between the four platelet glycoprotein polymorphisms i.e. GPIa C807T, VNTR and Kozak of glycoprotein Ibalpha, the HPA-1 of glycoprotein IIIa and the occurrence of branch retinal vein occlusion. The HPA-2 polymorphism was found in 18 out 60 (30%) patients with branch retinal vein occlusion in comparison with 27 out 142 (19%) of controls, with an estimated odds ratio of 1.8 (95% confidence interval, 0.91-3.65). The four platelet glycoprotein polymorphisms are not risk factors for branch retinal vein occlusion and therefore it seems unnecessary to screen those patients for it. A larger study is required, however, to determine whether HPA-2 is a novel risk factor for branch retinal vein occlusion.  相似文献   
6.
Endoscopic transthoracic sympathectomy: current indications and techniques   总被引:1,自引:0,他引:1  
Zusammenfassung GRUNDLAGEN: Die endoskopische thorakale Sympathektomie (ETS) existiert seit 60 Jahren als effektive Therapie der primären Hyperhidrose. Nach wie vor gibt es in der medizinischen Welt teils Vorbehalte, teils Unwissen über die Methode selbst, ihre Erfolgs- und Komplikationsraten sowie Nebenwirkungen. METHODIK: Nach Einführung in die Symptome und Behandlung der primären Hyperhidrose (konservativ und chirurgisch) werden Operationsmethoden und Langzeitergebnisse der ETS-Operation vorwiegend anhand der Daten aus der eigenen Abteilung präsentiert. ERGEBNISSE: Von 1965–2001 wurden 734 Sympathikotomien (ETS2–4) und bis 2003 weitere 103 Sympathikusblockaden (ESB4) bei Patienten mit primärer palmarer und axillärer Hyperhidrose durchgeführt. Die Konversionsrate betrug 0,1 %. Seit Einführung der Video-Thorakoskopie 1991 trat kein postoperatives Horner-Syndrom auf (zuvor 2,2 %), Drainage-pflichtige Pneumothoraces waren in 1,1 % zu verzeichnen. Nach einem medianen Follow-up von 16 Jahren waren 93 % der Extremitäten trocken, 5 % fast trocken und 2 % feucht. Nebenwirkungen traten in Form von kompensatorischem Schwitzen am Stamm (55 % insgesamt, davon 5 % stark) und gustatorischem Schwitzen (33 %) auf. Seit Einführung der limitierten Sympathikusblockade auf Höhe T4 (ESB4) konnte (bei naturgemäß kurzer Nachbeobachtungszeit) das kompensatorische Schwitzen auf 8,5 % und das gustatorische Schwitzen auf 2,1 % gesenkt werden. Mit dem postoperativen Ergebnis waren 100 % der Patienten nach ESB4 zufrieden, nach ETS2–4 waren 80 % zufrieden, 14 % teilweise zufrieden und 6 % unzufrieden (meist wegen starken kompensatorischen Schwitzens). SCHLUSSFOLGERUNGEN: Die ETS-Operation bietet hohe langfristige Erfolgsraten bei niedrigen Komplikationsraten. Patienten sollten über die zu erwartenden Nebenwirkungen genau aufgeklärt werden, für unzufriedene Patienten mit starkem kompensatorischem Schwitzen besteht nun die Möglichkeit der thorakoskopischen Klip-Entfernung.  相似文献   
7.
Aim:  To present an evidence-based framework to improve the quality of occupational therapy expert opinions on work capacity for litigation, compensation and insurance purposes.
Methods:  Grounded theory methodology was used to collect and analyse data from a sample of 31 participants, comprising 19 occupational therapists, 6 medical specialists and 6 lawyers. A focused semistructured interview was completed with each participant. In addition, 20 participants verified the key findings.
Results:  The framework is contextualised within a medicolegal system requiring increasing expertise. The framework consists of (i) broad professional development strategies and principles, and (ii) specific strategies and principles for improving opinions through reporting and assessment practices.
Conclusions:  The synthesis of the participants' recommendations provides systematic guidelines for improving occupational therapy expert opinion on work capacity.  相似文献   
8.
Improved embryo culture protocols now render more feasible the possibility of obtaining human blastocysts after in-vitro fertilization. In this study we present: (i) results of blastocyst development from supernumerary embryos after co-culture on green monkey kidney epithelial cells and (ii) pregnancy rates after transfer of frozen blastocysts. In addition, we have examined the influence of the day of blastocyst freezing and the day of transfer after the luteinizing hormone (LH) peak on pregnancy and implantation rates. Of 423 supernumerary embryos, 200 developed to the blastocyst stage (47.3%). By days 5 and 6, 67% of the blastocysts had reached the blastocyst stage, and were frozen, compared to 28.5% by day 7. When we compared the cases where only blastocysts frozen on days 5 and 6 were transferred compared to those frozen and transferred on or after day 7 the pregnancy rates were 7/18 (38.9%) and 1/16 (6.2%) respectively. In contrast, when we examined the influence of the day of transfer we found that pregnancies were established from day 5 up to day 9 post LH peak. Based on these results, we suggest that every attempt should be made to increase the development rate of supernumerary embryos to the blastocyst stage, as it appears that the quality of blastocysts transferred, as shown in this study by rate of development, plays a more crucial role than the timing of transfer.   相似文献   
9.
10.
The serum concentration of squamous-cell carcinoma antigen (SCC-A), a subfraction of tumour antigen, was determined by RIA from healthy donors (control group) and from patients with malignant cervical disease. Ninety-six percent (173/180) of the healthy patients had squamous-cell carcinoma antigen serum levels below 2 ng/ml. Ten of 70 (14.3%) patients with CIN III, 53.8% (34/62) of patients with invasive squamous-cell carcinoma stage I, 85.8% (30/35) with stage II and 96.5% (27/28) with stage III/IV had squamous-cell carcinoma antigen serum levels above 2 ng/ml. We observed that 22.5% (11/49) of patients with a tumour volume below 10 ml and 92.6% of patients with a tumour volume greater than 10 ml had squamous-cell carcinoma antigen levels above 2 ng/ml (p less than 0.005). SCC-A was correlated with recurrence or progressive disease in 90.0% of cases. Other risk factors such as depth of invasion, microscopic parametrial involvement, lymphatic and/or vascular space permeation and histological grade were not correlated with squamous-cell carcinoma antigen. Furthermore, this marker increased 4.3 +/- 2.7 months before clinical evidence of recurrence or progressive disease. We conclude that serial serum levels of squamous-cell carcinoma antigen provide a means for early detection of recurrence or progressive disease. This tumour marker might also be useful for monitoring the treatment effects and has some prognostic value.  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