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   3991篇
  免费   217篇
  国内免费   37篇
耳鼻咽喉   70篇
儿科学   110篇
妇产科学   94篇
基础医学   403篇
口腔科学   91篇
临床医学   397篇
内科学   883篇
皮肤病学   88篇
神经病学   314篇
特种医学   129篇
外科学   674篇
综合类   89篇
一般理论   3篇
预防医学   338篇
眼科学   76篇
药学   294篇
中国医学   20篇
肿瘤学   172篇
  2024年   5篇
  2023年   60篇
  2022年   159篇
  2021年   185篇
  2020年   135篇
  2019年   160篇
  2018年   178篇
  2017年   113篇
  2016年   133篇
  2015年   132篇
  2014年   152篇
  2013年   189篇
  2012年   303篇
  2011年   349篇
  2010年   161篇
  2009年   138篇
  2008年   225篇
  2007年   236篇
  2006年   216篇
  2005年   186篇
  2004年   178篇
  2003年   161篇
  2002年   154篇
  2001年   23篇
  2000年   20篇
  1999年   30篇
  1998年   25篇
  1997年   24篇
  1996年   14篇
  1995年   8篇
  1994年   9篇
  1993年   11篇
  1992年   11篇
  1991年   8篇
  1990年   17篇
  1989年   10篇
  1988年   5篇
  1987年   13篇
  1986年   10篇
  1985年   13篇
  1984年   6篇
  1983年   9篇
  1982年   4篇
  1981年   5篇
  1980年   5篇
  1979年   9篇
  1978年   7篇
  1977年   6篇
  1976年   4篇
  1937年   4篇
排序方式: 共有4245条查询结果,搜索用时 15 毫秒
61.
Obstructive sleep apnea (OSA) is a sleep disorder, increasingly recognized. It is commonly present in obese persons, treated with continuous positive airway pressure (CPAP), being the gold standard. The disorder has been associated with diabetes mellitus and possibly related to hypoxia per se, increased sympathetic activity, disturbed hypothalamic–pituitary–adrenal axis and increased inflammatory cytokines and leptin, all of which can adversely affect both glucose metabolism and insulin sensitivity. Given this association and the presence of common risk factors, this review assessed the impact of CPAP on diabetes mellitus through various metabolic parameters including HbA1c, nocturnal glucose and insulin resistance, in addition to the effect of CPAP on the prevention of diabetes mellitus. Results have been conflicting; Randomized controlled trials are recommended to allow objective and definite conclusions.  相似文献   
62.
63.
Aorta to pulmonary artery fistula is an uncommon and potentially fatal condition. This case is of a 48‐year‐old Caucasian male with congestive heart failure and multiple aortic valve replacement surgeries who presented with an acquired ascending aortic aneurysm to pulmonary artery fistula diagnosed using two‐dimensional transthoracic echocardiography via nonstandard imaging windows. Three‐dimensional transthoracic echocardiography using live/real time three‐dimensional color Doppler was used to assess the size of the opening of the fistula, providing additional value. This patient was surgically managed and is doing well 8 months postoperation.  相似文献   
64.
Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous inflammatory disorders of the respiratory tract characterized by airflow obstruction. It is now clear that the environmental factors that drive airway pathology in asthma and COPD, including allergens, viruses, ozone and cigarette smoke, activate innate immune receptors known as pattern-recognition receptors, either directly or indirectly by causing the release of endogenous ligands. Thus, there is now intense research activity focused around understanding the mechanisms by which pattern-recognition receptors sustain the airway inflammatory response, and how these mechanisms might be targeted therapeutically. One pattern-recognition receptor that has recently come to attention in chronic airways disease is the receptor for advanced glycation end products (RAGE). RAGE is a member of the immunoglobulin superfamily of cell surface receptors that recognizes pathogen- and host-derived endogenous ligands to initiate the immune response to tissue injury, infection and inflammation. Although the role of RAGE in lung physiology and pathophysiology is not well understood, recent genome-wide association studies have linked RAGE gene polymorphisms with airflow obstruction. In addition, accumulating data from animal and clinical investigations reveal increased expression of RAGE and its ligands, together with reduced expression of soluble RAGE, an endogenous inhibitor of RAGE signalling, in chronic airways disease. In this review, we discuss recent studies of the ligand–RAGE axis in asthma and COPD, highlight important areas for future research and discuss how this axis might potentially be harnessed for therapeutic benefit in these conditions.  相似文献   
65.
The relation between cancer and coagulation is the subject of investigation since a relation between tumor and thrombosis has been determined. Antithrombin III is an important thrombin inhibitor, and increased thrombin?Cantithrombin (TAT) complex levels activate coagulation. Activated thrombin activatable fibrinolysis inhibitor (TAFI) inhibits the conversion of plasminogen to plasmin. In addition, it directly inactivates plasmin. Defective fibrinolysis increases the risk of thrombosis. In this study, we evaluated homeostatic parameters, TAFI, and TAT levels in patients with gastric cancer applying to the medical oncology outpatient clinic. Fifty-two patients and 35 healthy controls were included. ELISA was used to measure TAFI and TAT complex levels. These were statistically higher in the patient group (p?<?0.05 and p?=?0.001, respectively). D-dimer levels were higher in stage IV (p?=?0.05). Correlations between lymph nodes and TAFI and TAT levels were examined. Weak but positive correlation between lymph nodes and TAFI was detected (R?=?0.452, p?=?0.027). TAFI and TAT levels were evaluated using relative operating characteristic analysis to differentiate the disease. TAT was more specific than TAFI according to this analysis (TAFI area under curve (AUC), 0.676; TAT AUC, 0.874). Thrombotic events and bleeding disorders need to be borne in mind in gastric cancer. This situation is due to the impairment of the balance between coagulation and fibrinolysis. Further studies are now needed to evaluate the effects of TAFI and TAT on survey and prognosis as well as the potential of these parameters as tumor markers for gastric cancer.  相似文献   
66.
67.
Laparoscopic repair of paraesophageal hernia is safe and feasible and can provide comparable results for patients with type IV paraesophageal hernia. We report a rare case of mediastinal seroma in an 80-year-old gentleman who had a giant type IV paraesophageal hernia and was eventually admitted to our hospital for elective laparoscopic repair and recovered very well after surgery with resolution of the atelectatic lungs and air-fluid collection in his chest.  相似文献   
68.
Photorhabdus temperata is an entomopathogenic enterobacterium; it is a nematode symbiont that possesses pathogenicity islands involved in insect virulence. Herein, we constructed a P. temperata M1021 cosmid library in Escherichia coli XL1-Blue MRF` and obtained 7.14 × 105 clones. However, only 1020 physiologically active clones were screened for insect virulence factors by injection of each E. coli cosmid clone into Galleria mellonella and Tenebrio molitor larvae. A single cosmid clone, PtC1015, was consequently selected due to its characteristic virulent properties, e.g., loss of body turgor followed by death of larvae when the clone was injected into the hemocoel. The sequence alignment against the available sequences in Swiss-Prot and NCBI databases, confirmed the presence of the mcf gene homolog in the genome of P. temperata M1021 showing 85% homology and 98% query coverage with the P. luminescens counterpart. Furthermore, a 2932 amino acid long Mcf protein revealed limited similarity with three protein domains. The N-terminus of the Mcf encompassed consensus sequence for a BH3 domain, the central region revealed similarity to toxin B, and the C-terminus of Mcf revealed similarity to the bacterial export domain of ApxIVA, an RTX-like toxin. In short, the Mcf toxin is likely to play a role in the elimination of insect pests, making it a promising model for use in the agricultural field.  相似文献   
69.
To look at the prevalence of phonatory symptoms in patients with type 2 diabetes mellitus. The correlation between these symptoms with duration of the disease, glycemic control, and neuropathy will be described. A total of 105 consecutive patients diagnosed with type 2 diabetes mellitus by their primary endocrinologist were evaluated. A control group consisting of 33 healthy subjects was recruited for this study. Demographic data included: age, gender, allergy, smoking, duration of the disease, glycemic control, and presence or absence of neuropathy. Subjects were also asked about the presence or absence of the following symptoms: hoarseness, vocal tiring or fatigue, vocal straining, and aphonia or complete loss of voice. Patients were also asked to fill out the Voice Handicap Index 10. The mean age of patients with diabetes was 53.21 + 9.68 years with male-to-female ratio of 2/3. The most common phonatory symptoms were vocal tiring or fatigue and hoarseness (34.3 and 33.3 %). There was a significant difference in the prevalence of hoarseness and vocal straining (p value 0.045 and 0.015, respectively) compared to controls. There was a significant correlation between glycemic control, neuropathy, and hoarseness (p value 0.030 and 0.001, respectively). Vocal straining and aphonia also correlated significantly with the presence of neuropathy. Close to 16 % of diabetic patients had a VHI-10 above or equal to 7. Diabetic patients are more likely to have phonatory symptoms compared to controls, namely straining and hoarseness. One out of seven patients with diabetes has reported that phonatory symptoms had a significant impact on their quality of life. The presence of neuropathy and poor glycemic control should alert the treating physician to these vocal complaints.  相似文献   
70.
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