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   2349篇
  免费   138篇
  国内免费   27篇
耳鼻咽喉   21篇
儿科学   112篇
妇产科学   46篇
基础医学   239篇
口腔科学   196篇
临床医学   178篇
内科学   506篇
皮肤病学   44篇
神经病学   135篇
特种医学   174篇
外科学   221篇
综合类   50篇
预防医学   286篇
眼科学   30篇
药学   146篇
中国医学   13篇
肿瘤学   117篇
  2023年   35篇
  2022年   63篇
  2021年   96篇
  2020年   58篇
  2019年   65篇
  2018年   74篇
  2017年   57篇
  2016年   55篇
  2015年   64篇
  2014年   90篇
  2013年   102篇
  2012年   173篇
  2011年   150篇
  2010年   90篇
  2009年   70篇
  2008年   125篇
  2007年   94篇
  2006年   109篇
  2005年   94篇
  2004年   69篇
  2003年   55篇
  2002年   65篇
  2001年   36篇
  2000年   43篇
  1999年   48篇
  1998年   39篇
  1997年   47篇
  1996年   49篇
  1995年   25篇
  1994年   32篇
  1993年   28篇
  1992年   23篇
  1991年   19篇
  1990年   25篇
  1989年   36篇
  1988年   33篇
  1987年   19篇
  1986年   29篇
  1985年   9篇
  1984年   13篇
  1983年   10篇
  1982年   12篇
  1981年   5篇
  1980年   11篇
  1979年   5篇
  1978年   12篇
  1977年   7篇
  1976年   16篇
  1975年   7篇
  1965年   3篇
排序方式: 共有2514条查询结果,搜索用时 15 毫秒
41.
Developmental toxicity caused by environmental exposure to heavy metals during the perinatal period has raised questions about offspring health. Cadmium (Cd) is an endocrine‐disrupting chemical with the potential to interfere with morphogenesis and susceptibility to diseases in reproductive organs. Taking into account that in the rat prostate morphogenesis occurs during the perinatal period, and that pregnant females absorb and retain more dietary Cd than their non‐pregnant counterparts, it is important to understand the effects of perinatal Cd exposure on the adult rat prostate. Therefore this study investigated the effects of gestational and lactational Cd exposure on adult offspring rat prostate histopathology. Pregnant rats (n = 20) were divided into two groups: Control (treated with aqueous solution of sodium acetate 10 mg/l) and treated (treated with aqueous solution of cadmium acetate 10 mg/l) administered in the drinking water. After weaning, male offspring from different litters (n = 10) received food and water ‘ad libitum’. The animals were euthanized at postnatal day 90 (PND90), the ventral prostates (VPs) were removed, weighed and examined histopathologically. Blood was collected for the measurement of testosterone (T) levels. Immunohistochemistry for androgen receptor (AR) and Ki67, and a TUNEL assay were performed. There were no differences in T levels, cell proliferation and apoptosis indexes, or AR immunostaining between the experimental groups. Stromal inflammatory foci and multifocal inflammation increased significantly in the treated group. These changes were associated with inflammatory reactive epithelial atypia and stromal fibrillar rearrangement. In conclusion, VP was permanently affected by perinatal Cd exposition, with increased incidence of inflammatory disorders with ageing.  相似文献   
42.
This study reports the case of a patient with a severely resorbed mandible who was treated without a bone graft, using short implants, internal rigid fixation, rhBMP-2 and β-tricalcium phosphate. A 76-year-old woman, with a severely resorbed mandible (less than 3 mm), reported a history of nearly 25 years of complete edentulism and consecutive treatment failures, with total bilateral exposed inferior alveolar nerves and complete bone resorption of the inferior border in some areas. The treatment of choice was the placement of a 2.0 mm thick unilock bone plate (MatrixMandible, Synthes Maxillofacial, Paoli, PA, USA), to reinforce the mandible. Eight short implants with a regular platform (Nobel Biocare, Goteborg, Sweden) were placed: three on the external oblique line on both sides and two on the symphysis. In order to augment mandible height and coat the exposed thread of the anterior implants, rhBMP-2 (Infuse Bone, Meditronic Sofamor Danek, Memphis, TN, USA) and β-tricalcium phosphate (Cerasorb; Curasan, Kleinostheim, Germany) were used. Four 1.3 mm L miniplates were placed to support the graft. 14 months after surgery, the patient was satisfied and had excellent function without complications.  相似文献   
43.
Apical hypertrophic cardiomyopathy (HCM) is an uncommon variant of HCM characterized by apical hypertrophy without the septal predominance seen in the majority of HCM cases. In 2% of patients, a concomitant left ventricular apical aneurysm is observed, which increases the risk of sudden death and adverse HCM‐related events. Multimodality imaging is helpful for appropriate identification of this particular morphologic pattern. Herein, we present a case of apical HCM with a left ventricular apical aneurysm, exemplifying the utility of a multimodality approach from resting electrocardiogram, transthoracic echocardiogram, left ventriculography, and cardiac magnetic resonance imaging, for proper risk stratification and treatment planning.  相似文献   
44.
The aims of the present study were (i) to assess the in vitro genetic stability of S19 and RB51 Brucella abortus vaccines strains and (ii) to evaluate the ability of multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) as a tool to be used in the quality control of live vaccines against brucellosis. Sixty-three batches of commercial S19 (n = 53) and RB51 (n = 10) vaccines, produced between 2006 and 2009, were used in this study. S19 and RB51 vaccines were obtained from, respectively, seven and two different manufacturers. Ten in vitro serial passages were performed on reference strains and on selected batches of commercial vaccines. All batches, reference strains and strains of serial passages were typed by the MLVA16. The results demonstrated that B. abortus S19 and RB51 vaccine strains are genetically stable and very homogeneous in their respective groups. Anyway, batches of S19 from one manufacturer and batches of RB51 from another presented genotypes distincts from the reference vaccine strains. In both cases, differences were found on locus Bruce07, which had addition of one repeat unit in the case of S19 batches and the deletion of one repeat unit in the case of RB51 batches. In summary, MLVA16 proved to be a molecular tool capable of discriminating small genomic variations and should be included in in vitro official tests.  相似文献   
45.
46.
The rapidly increasing number of cases of Zika virus and limited understanding of its congenital sequelae (e.g., microcephaly) led to stories of fear and uncertainty across social media and other mass communication networks. In this study, we used techniques generic to netnography, a form of ethnography, using Internet‐based computer‐mediated communications as a source of data to understand the experience and perceptions of families with infants diagnosed with Zika‐related microcephaly. We screened 27 YouTube? videos published online between October 2015 and July 2016, during which the Zika epidemic started, peaked, and declined. We identified three themes: (a) experiencing the news of a diagnosis of Zika‐associated microcephaly; (b) experiencing feelings and expectations of the ‘imperfect’ child; and (c) seeking to understand microcephaly to care for the child. We found that families experienced distressing feelings of shock, sadness, hopelessness, and pain, while dealing with emerging and sometimes conflicting information being transmitted by news outlets, uncertainty about the child's health, and healthcare providers’ lack of clarity to guide the family members. The ‘unknown’ factor of ZIKA was an additional stressful factor in the experience of the families.  相似文献   
47.
48.
The aim of this prospective, randomized, controlled, paired trial was to perform a comparative analysis of the preemptive analgesic effect of nimesulide and tramadol chlorhydrate during third molar surgery. The study was carried out between March and November 2009, involving 94 operations in 47 male and female patients with bilateral impacted lower third molars in comparable positions. The sample was divided into two groups. Group A received an oral dose of 100 mg of nimesulide 1 h prior to surgery. Group B received an oral dose of 100 mg of tramadol chlorhydrate 1 h prior to surgery. The following aspects were evaluated in the postoperative period: adverse effects of the drugs; amount of rescue medication used (acetaminophen 750 mg); and pain 5, 6, 24, 36, 48, 60, 72 and 84 h after surgery using a visual analog pain scale. Peak pain occurred 5 h after surgery in both groups, with a mean pain score of 2.3 in Group A and 3.0 in Group B; this difference did not achieve statistical significance (p > 0.141). Based on the sample studied, nimesulide and tramadol chlorhydrate demonstrate similar preemptive analgesic effects when used in lower third molar surgeries.  相似文献   
49.
Diaphragm ultrasound (DUS) has been used to identify diaphragm dysfunction. However, its correlations with respiratory strength and lung function are unclear, even in healthy patients. A total of 64 healthy patients (30 males) had lung function and inspiratory strength (maximal inspiratory pressure and sniff nasal inspiratory pressure) measured. Gastric and oesophageal pressures were measured in a subgroup (n?=?40). DUS was characterized by mobility (quiet breathing [QB] and deep breathing [DB]) and thickness (at functional residual capacity [ThFRC] and total lung capacity [ThTLC]). We calculated the thickening fraction (TF). During QB, DUS was similar between sexes. However, during DB, females had lower mobility, thickness and TF than males. Mobility at DB, ThTLC and TF significantly correlated with lung function and inspiratory strength. These correlations were affected by sex. DUS correlated with inspiratory gastric pressure. In healthy patients, DUS correlated with lung function and inspiratory strength during DB. Significant differences between genders were noticeable when DUS was performed during DB.  相似文献   
50.
The traumatic bone cyst is characterized by the presence of an asymptomatic sinus devoid of epithelial lining, which is rarely found in the jaws.ObjectiveTo describe the clinical, surgical and radiographic findings of traumatic bone cysts.Material and MethodA retrospective study was made of patients diagnosed with traumatic bone cysts at an oral pathology department from 1992 to 2007. Data on the clinical, radiographic and surgical complications were gathered.ResultsTwenty-six cases of traumatic bone cyst were diagnosed in 15 years; 17 were male and 09 were female. Most patients were within first two decades of life and had no pain or history of trauma in the affected area. The multilocular pattern was observed in only seven cases, its radiographic appearance suggests a tumor. Air was found inside the lesion in about 70% of cases; serous fluid with blood and blood only were uncommon within the lesions.ConclusionA higher prevalence in young patients, absence of a history of trauma, and a small number of lesions containing serous fluid with blood reflects the need to discuss the true pathogenesis of traumatic bone cysts.  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