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   9422篇
  免费   587篇
  国内免费   33篇
耳鼻咽喉   47篇
儿科学   260篇
妇产科学   156篇
基础医学   1821篇
口腔科学   247篇
临床医学   773篇
内科学   1890篇
皮肤病学   293篇
神经病学   1193篇
特种医学   308篇
外科学   816篇
综合类   42篇
一般理论   6篇
预防医学   522篇
眼科学   142篇
药学   578篇
中国医学   21篇
肿瘤学   927篇
  2024年   6篇
  2023年   61篇
  2022年   136篇
  2021年   232篇
  2020年   183篇
  2019年   248篇
  2018年   285篇
  2017年   183篇
  2016年   280篇
  2015年   298篇
  2014年   383篇
  2013年   495篇
  2012年   723篇
  2011年   773篇
  2010年   407篇
  2009年   422篇
  2008年   629篇
  2007年   666篇
  2006年   621篇
  2005年   619篇
  2004年   587篇
  2003年   536篇
  2002年   446篇
  2001年   76篇
  2000年   68篇
  1999年   84篇
  1998年   118篇
  1997年   71篇
  1996年   66篇
  1995年   58篇
  1994年   43篇
  1993年   37篇
  1992年   21篇
  1991年   21篇
  1990年   16篇
  1989年   19篇
  1988年   8篇
  1987年   8篇
  1986年   11篇
  1985年   10篇
  1984年   6篇
  1983年   11篇
  1981年   4篇
  1979年   9篇
  1978年   4篇
  1977年   4篇
  1975年   5篇
  1973年   5篇
  1972年   6篇
  1963年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Configuration of the interdisciplinary emergency unit within the university clinic of G?ttingen was successfully reorganized during the past two years. All emergencies except traumatologic, gynecologic and pediatric emergencies are treated within this functional unit which is guided by the center of internal medicine. It is organized in a three shift operation manner over a period of 24 hours. Due to a close interdisciplinary collaboration between different departments patients receive optimal diagnostic and therapeutic treatment within a short period of time. To improve processes within the emergency department a series of measures were taken including the -establishment of an intermediate care unit for unstable patients, setting up of special diagnostic and therapeutic units for the acute coronary syndrome as well as stroke, implementation of standardized clinical pathways, establishment of an electronic data processing network in close communication with all diagnostic entities, introduction of a quality assurance system and reduction of medical costs. Reorganization measures lead to a substantial optimization and acceleration of emergency proceedings and thus, provides optimal patient care around the clock. In addition, medical costs could clearly be reduced at the interface between preclinical and clinical emergency medicine.  相似文献   
82.
From January 2003 to June 2006, 6 patients with leakage of the cervical esophagogastrostomy after esophagectomy and gastric pull-up underwent endoscopic stenting using the self-expandable covered tracheal type device. Anastomotic healing was satisfactory. Stent extraction was performed after an average interval of 91 days. Initial stent migration occurred in 2 patients and post-extraction stenosis developed in 3 patients. Insertion of a self-expandable covered metal tracheal stent represents a safe approach resulting in immediate closure and subsequent healing of cervical anastomotic leakage.  相似文献   
83.
Impaired hepatic arterial perfusion after orthotopic liver transplantation (OLT) may lead to ischemic biliary tract lesions and graft‐loss. Hampered hepatic arterial blood flow is observed in patients with hypersplenism, often described as arterial steal syndrome (ASS). However, arterial and portal perfusions are directly linked via the hepatic arterial buffer response (HABR). Recently, the term ‘splenic artery syndrome’ (SAS) was coined to describe the effect of portal hyperperfusion leading to diminished hepatic arterial blood flow. We retrospectively analyzed 650 transplantations in 585 patients. According to preoperative imaging, 78 patients underwent prophylactic intraoperative ligation of the splenic artery. In case of postoperative SAS, coil‐embolization of the splenic artery was performed. After exclusion of 14 2nd and 3rd retransplantations and 83 procedures with arterial interposition grafts, SAS was diagnosed in 28 of 553 transplantations (5.1%). Twenty‐six patients were treated with coil‐embolization, leading to improved liver function, but requiring postinterventional splenectomy in two patients. Additionally, two patients with SAS underwent splenectomy or retransplantation without preceding embolization. Prophylactic ligation could not prevent SAS entirely (n = 2), but resulted in a significantly lower rate of complications than postoperative coil‐embolization. We recommend prophylactic ligation of the splenic artery for patients at risk of developing SAS. Post‐transplant coil‐embolization of the splenic artery corrected hemodynamic changes of SAS, but was associated with a significant morbidity.  相似文献   
84.
BACKGROUND: Cervicothoracic neuroblastoma originates from the cervical sympathetic nerves and ganglia and thus presents a problem when dissecting the vascular and nervous elements of the subclavian region. The standard operation is based on thoracotomy or dual cervicotomy/thoracotomy, but these approaches do not provide optimal control of the subclavian vessels. We report our experience in children with cervicothoracic neuroblastoma by using a technique usually performed for apical lung cancer. METHODS: Four patients with localized cervicothoracic neuroblastoma with no N-myc amplification were resected after chemotherapy by this approach. The anatomic evaluation was performed preoperatively with angio-magnetic resonance imaging. This transmanubrial approach, performed through a manubrial L-shaped transection and first costal cartilage resection, affords excellent access to the subclavian region with safe control of the vessels and nerves and exposure of the first 4 thoracic intervertebral foramina. RESULTS: Removal of more than 90% of the tumor was possible in all cases. The postoperative course was uneventful in 3 cases, and the fourth patient with a left-sided tumor had a transient chylothorax. No recurrence occurred with a follow-up period of 8 to 32 months. CONCLUSIONS: The transmanubrial approach is an osteomuscular-sparing technique that seems particularly suitable for the treatment of these tumors, which require a resection that is as complete as possible to avoid postoperative chemotherapy and tumor relapse.  相似文献   
85.
Background/aims: Understanding structural and functional differences between facial areas is necessary for the formulation of cosmetics and dermatological preparations well tailored to the skin's biophysical characteristics. The objective of the present study was to compare biophysical parameters on malar and frontal facial areas of healthy women classified according to self-reported cosmetic skin types.
Methods: The study population comprised 253 women aged from 20 to 50 years who did not display any signs of dermatological disease. Women declared spontaneously their cosmetic skin type. Skin capacitance, sebum casual level, skin temperature, transepidermal water loss (TEWL), skin colour and relief were assessed on cheeks and forehead in a controlled environment.
Results: All biophysical parameters showed statistically significant differences between the two zones. Mean a* chromametric values and TEWL values were significantly higher on cheeks. In contrast, mean b * chromametric values and sebum casual levels showed the highest values on the forehead. Moreover, skin capacitance, temperature, roughness and L .* chromametric value showed minor, while statistically significant, differences between the two zones. With marginal exceptions, the differences between the facial zones for each biophysical parameter remained statistically significant, irrespective of self-reported skin type.
Conclusion: Biophysical parameter mean values differ between frontal and malar zones regardless of self-reported skin type. Except for the elevated sebum casual levels in greasy and combined skin, no single or combined biophysical characteristics could be linked to any of the self-reported skin types. Furthermore our data confirm that in contrast to the common belief that dry skin is associated with reduced sebum production, sebum levels in women declaring to have dry skin and those declaring to have normal skin were not found to be different.  相似文献   
86.
87.
BACKGROUND/PURPOSE: The objective was to compare the efficiencies of the 595 nm pulsed dye and the 1320 nm Nd : YAG laser non-ablative rejuvenation. METHODS: KM mice were irradiated with the 595 nm pulsed dye and the 1320 nm Nd : YAG lasers. Histological changes were evaluated immediately, 1, 7, 21, 30 and 60 days after the two laser treatments. Skin hydration and hydroxyproline content were measured to quantify the degree of improvement of the skin's water-holding capacity and the rate of hydroxyproline synthesis. RESULTS: Although not statistically significant, the 1320 nm Nd : YAG laser treatment induced 9.7% greater improvement of skin hydration than the 595 nm laser while the 595 nm pulsed dye laser treatment led to a thicker dermis and 8.7% greater increase of hydroxyproline than the 1320 nm laser. More than 50% increase of collagen type I was observed in 75% of 595 nm laser-treated sites and 42% of 1320 nm laser-treated sites, and more than 25% increase of collagen type III was observed in 75% of 595 nm laser-treated sites and 50% of 1320 nm laser-treated sites. The 595 nm laser treatment was better in increasing the amount of collagen fibers, especially collagen type I (P < 0.05). CONCLUSION: Our results demonstrated that the 595 nm laser appeared to be more effective in increasing new collagen formation, while the 1320 nm laser was superior to the 595 nm laser in improving the skin's water-holding capacity.  相似文献   
88.
Background: Specific cutaneous infiltrates in patients with leukemia generally carry a grim prognosis. However, non-neoplastic skin diseases may be associated with recruitment of normal and neoplastic leukocytes circulating in the peripheral blood. In those instances, neoplastic cells may be detected in skin lesions without an adverse effect on prognosis. Methods: In a patient with B-cell chronic lymphocytic leukemia, a specific infiltrate developed at the site of a florid herpes simplex infection. Clinically, the lesion presented itself as an ulcerated tumor. Results: Histopathologically, the lesion was characterized by a dense, diffuse infiltrate of small hyperchromatic lymphocytes throughout the entire dermis. Lymphocytes showed an aberrant CD20(+)/CD43(+)/CD5(+) phenotype of neoplastic B cells, and monoclonal rearrangement of immunoglobulin gamma genes could be demonstrated by polymerase chain reaction. Although criteria for leukemia cutis were fulfilled, the patient did well. Conclusions: The cutaneous infiltrate of neoplastic cells seemed to be part of a physiologic response to the antigenic stimulus, rather than indicating an exacerbation of leukemia. Ziemer M, Bornkessel A, Hahnfeld S, Weyers W. 'Specific' cutaneous infiltrate of B-cell chronic lymphocytic leukemia at the site of a florid herpes simplex infection.  相似文献   
89.
90.
BACKGROUND: In patients with a first symptomatic pulmonary embolism (PE), the risk of recurrence is unknown. We therefore investigated the risk of recurrence among patients with spontaneous symptomatic PE and among those with deep vein thrombosis (DVT) without symptoms of PE. METHODS: After discontinuation of secondary thromboprophylaxis for a first venous thromboembolism (VTE), we prospectively observed 436 patients for an average of 30 months. Patients with secondary VTE, natural inhibitor deficiencies, lupus anticoagulant, cancer, long-term antithrombotic therapy, vena cava filters, or pregnancy were excluded. The study outcome was objectively documented recurrent symptomatic VTE. RESULTS: Recurrent VTE was seen among 28 (17.3%) of 162 patients with symptomatic PE and among 26 (9.5%) of 274 patients with DVT without symptoms of PE. Compared with patients with DVT, the relative risk of recurrent VTE among patients with symptomatic PE was 2.2 (95% confidence interval, 1.3-3.7; P =.005). The relative risk was not affected by age, sex, presence of factor V Leiden or prothrombin G20210A, hyperhomocysteinemia, or high factor VIII levels. Compared with patients with DVT without symptoms of PE, patients with symptomatic PE had an adjusted relative risk of PE at recurrence of 4.0 (95% confidence interval, 1.3-12.3; P =.03). CONCLUSION: Patients with a first symptomatic PE not only have a higher risk of recurrent VTE than those with DVT without symptoms of PE, but are also at high risk of symptomatic PE at recurrence.  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