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   10095篇
  免费   645篇
  国内免费   41篇
耳鼻咽喉   50篇
儿科学   275篇
妇产科学   157篇
基础医学   1878篇
口腔科学   249篇
临床医学   891篇
内科学   1978篇
皮肤病学   301篇
神经病学   1219篇
特种医学   333篇
外科学   1073篇
综合类   52篇
一般理论   6篇
预防医学   525篇
眼科学   246篇
药学   590篇
中国医学   20篇
肿瘤学   938篇
  2023年   58篇
  2022年   129篇
  2021年   233篇
  2020年   181篇
  2019年   250篇
  2018年   290篇
  2017年   187篇
  2016年   285篇
  2015年   303篇
  2014年   385篇
  2013年   505篇
  2012年   741篇
  2011年   788篇
  2010年   423篇
  2009年   433篇
  2008年   637篇
  2007年   688篇
  2006年   640篇
  2005年   649篇
  2004年   624篇
  2003年   565篇
  2002年   494篇
  2001年   132篇
  2000年   108篇
  1999年   120篇
  1998年   140篇
  1997年   84篇
  1996年   79篇
  1995年   67篇
  1994年   51篇
  1993年   40篇
  1992年   45篇
  1991年   51篇
  1990年   39篇
  1989年   30篇
  1988年   20篇
  1987年   28篇
  1986年   20篇
  1985年   22篇
  1984年   14篇
  1983年   16篇
  1979年   14篇
  1976年   9篇
  1975年   11篇
  1974年   9篇
  1972年   13篇
  1971年   13篇
  1970年   10篇
  1969年   10篇
  1968年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
PURPOSE: To compare tests for intestinal function with clinical scores after abdominal irradiation. PATIENTS AND METHODS: At the Department of Radiotherapy, Erfurt, Germany, intestinal changes were studied in 91 patients receiving abdominal radiotherapy between 1992 and 1996. Conventional fractionation (1.8-2 Gy per fraction, total doses 30.6-62.5 Gy) was applied. Before and at weekly intervals during radiotherapy, the clinical response was scored according to RTOG/EORTC for the upper and lower gastrointestinal (GI) tract. Resorption tests for vitamin B(12) and D-xylose were performed before the onset and immediately after treatment. RESULTS: The clinical response displayed a well-defined dose-effect relationship with grade 1 effects in 5% and 50% of the patients at about 10 Gy and 50 Gy, respectively. For grade 2 reactions, 5%- and 50%-effective doses were 20-30 Gy and 60-80 Gy. Effects in the upper and lower GI tract were highly correlated. Changes in body weight did not show a correlation with other clinical symptoms. Changes in resorption also displayed a significant dose effect. However, no correlation was found with the clinical symptoms in the individual patient. CONCLUSION: In the present study, the clinical manifestation of intestinal side effects according to RTOG/EORTC criteria was reflected by neither the vitamin B(12) nor by the D-xylose resorption test. Hence, these tests cannot be regarded as useful for objective quantitation of intestinal radiation injury.  相似文献   
7.

Introduction  

Planning human resources for health (HRH) is a complex process for policy-makers and, as a result, many countries worldwide swing from surplus to shortage. In-depth case studies can help appraising the challenges encountered and the solutions implemented. This paper has two objectives: to identify the key challenges in HRH planning in Belgium and to formulate recommendations for an effective HRH planning, on the basis of the Belgian case study and lessons drawn from an international benchmarking.  相似文献   
8.
Background: Hemoglobin solutions combine volume effect, oxygen-carrying capacity, and vasoactive properties, the latter facilitating restoration of global hemodynamics but endangering microvascular resuscitation. Hemoglobin-evoked vasoconstriction probably is due to nitric oxide scavenging, which can be reduced by genetic modifications of the heme pocket. This study compares resuscitation with a nonhemoglobin colloid and two recombinant hemoglobin solutions with wild-type and reduced nitric oxide-scavenging capacity.

Methods: Twenty-seven awake Syrian golden hamsters fitted with dorsal skinfold chambers underwent a 30 min-hemorrhagic shock (mean arterial pressure [MAP] 30-35 mmHg) and resuscitation with shed blood volume of either 6% dextran 60 (Biophausia, Uppsala, Sweden), recombinant hemoglobin 1.1 (rHb1.1; wild-type nitric oxide-scavenging capacity; 10 g/dl), or recombinant hemoglobin 2.0 (rHb2.0; reduced nitric oxide-scavenging capacity; 10 g/dl; both Baxter Healthcare, Boulder, CO). Macrohemodynamic and laboratory parameters were assessed; microvascular parameters in the skinfold chamber were analyzed by intravital microscopy.

Results: Hemorrhagic shock reduced functional capillary density (FCD) by 70% and caused significant metabolic acidosis. Colloid resuscitation led to incomplete recovery of MAP and FCD. Infusion of rHb1.1 completely restored MAP but not FCD, with the smallest arteriolar diameters found in this group. FCD was restored best by resuscitation with rHb2.0, although MAP was lower than in rHb1.1-treated animals. Metabolic acidosis was resolved by both hemoglobin solutions, but not by dextran.  相似文献   

9.
The purpose of the study was to determine the incidence, risk factors, treatment, and influence on survival of patients with de novo esophageal cancer after liver transplantation (LT). From 1988 to 2006, 1,926 patients underwent LT in our institution. A total of 9 patients (0.5%) developed a de novo esophageal cancer and 1 patient a cancer of the cardia (0.05%). A retrospective analysis was performed to reveal underlying diseases, timeframes between LT and appearance of cancer, predisposing factors, cancer therapy, complications, immunosuppressive regimens, and survival. Of our 10 patients, 7 (70%) suffered from esophageal squamous cell carcinoma (SCC) and 3 patients (30%) developed an adenocarcinoma, including the patient with cancer of the cardia. A total of 9 patients were transplanted due to alcoholic cirrhosis; 1 patient suffered from hepatocellular carcinoma in nonA-nonB hepatitis-related cirrhosis. Median time to tumor diagnosis was 51 months after transplantation. A total of 5 patients were treated conservatively with combined radiochemotherapy and 5 underwent surgical resection. Patients with radiochemotherapy showed a mean survival of 14.8 months vs. 24.8 months for the patients of the surgery group. No major postoperative complication has been observed. A total of 2 patients of the surgery group are still alive after a follow-up of 15 and 89 months. In conclusion, de novo esophageal and cancer of the cardia after LT is a rare event. In spite of immunosuppression, no increased complication rate has been observed. Patients may have a survival benefit from surgical resection.  相似文献   
10.
Recently, a resin-based calcium phosphate cement (RCPC) has been reported as a remineralizing pulp-capping or lining cement. RCPC consists mainly of tetracalcium and dicalcium phosphates, ethoxylated bisphenol A dimethacrylate and pyromellitic glycerol dimethacrylate monomers and photo- and chemical initiators. OBJECTIVES: Here, the cytotoxic effects of RCPC were evaluated. The hypothesis was that RCPC induced only minor cytotoxic response in immortalized murine odontoblast and pulp cells, comparable to that produced by similar dimethacrylates due to unpolymerized dimethacrylate monomer present after curing. METHODS: Cytotoxicity was determined following the changes in cell succinate dehydrogenase activity after 24 h exposure to the cement components and after a 24 h recovery period. A fourfold range of concentrations was tested of the monomers, the eluate of cured RCPC leached in Dulbecco's modified Eagle's medium, and crushed cured cement in dimethyl sulfoxide. RESULTS: The monomers themselves had cytotoxicities similar to those reported for other dimethacrylates, although they are significantly less toxic than Bis-GMA. Differential cell sensitivity was demonstrated, with the pulp cells having greater sensitivity to the unpolymerized monomer than the odontoblast-like cells. The leached components have cytotoxicity similar to that of the free monomers. The crushed material demonstrated no apparent cytotoxicity at the dilutions tested. SIGNIFICANCE: These data demonstrate that RCPC has an in vitro cytotoxicity that is comparable to other materials containing dimethacrylate monomers and suggest that the material may be suitable for use in dental restorations. The data also indicate that the pulp cells appear more sensitive to dimethacrylates than the odontoblasts.  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