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   2732篇
  免费   163篇
  国内免费   12篇
耳鼻咽喉   54篇
儿科学   139篇
妇产科学   53篇
基础医学   339篇
口腔科学   45篇
临床医学   272篇
内科学   559篇
皮肤病学   34篇
神经病学   111篇
特种医学   376篇
外科学   324篇
综合类   76篇
一般理论   1篇
预防医学   105篇
眼科学   41篇
药学   192篇
中国医学   22篇
肿瘤学   164篇
  2023年   21篇
  2022年   43篇
  2021年   61篇
  2020年   36篇
  2019年   53篇
  2018年   62篇
  2017年   45篇
  2016年   52篇
  2015年   61篇
  2014年   107篇
  2013年   108篇
  2012年   141篇
  2011年   139篇
  2010年   131篇
  2009年   102篇
  2008年   115篇
  2007年   88篇
  2006年   101篇
  2005年   102篇
  2004年   77篇
  2003年   69篇
  2002年   84篇
  2001年   74篇
  2000年   60篇
  1999年   59篇
  1998年   64篇
  1997年   77篇
  1996年   61篇
  1995年   49篇
  1994年   58篇
  1993年   58篇
  1992年   26篇
  1991年   54篇
  1990年   41篇
  1989年   53篇
  1988年   52篇
  1987年   38篇
  1986年   48篇
  1985年   43篇
  1984年   25篇
  1983年   25篇
  1982年   24篇
  1981年   24篇
  1980年   25篇
  1979年   9篇
  1978年   9篇
  1977年   15篇
  1976年   12篇
  1975年   17篇
  1971年   2篇
排序方式: 共有2907条查询结果,搜索用时 31 毫秒
11.
Hodgkin disease: CT of the thymus   总被引:2,自引:0,他引:2  
Heron  CW; Husband  JE; Williams  MP 《Radiology》1988,167(3):647-651
The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.  相似文献   
12.
Solitary bronchioloalveolar carcinoma: CT criteria   总被引:14,自引:0,他引:14  
The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.  相似文献   
13.
The study of the HLA system was primarily initiated to understand the basis for the histocompatibility between recipients and tissue donors. HLA typing methods are being continuously improved and biochemical and molecular typing, in particular, are expected to provide precise typing of the HLA system. Conventional HLA typing methods can define antigen specificities, while biochemical and molecular methods will provide direct allele typing that is based on the actual sequence polymorphism. The precise tissue typing will definitely improve the outcome of transplantation. Structural studies have revealed the highly polymorphic nature of the HLA system and given insight to understanding the molecular basis of the HLA polymorphism. One big immunological puzzle remaining to be answered is how T-cell receptor molecules recognize peptide antigen in conjunction with the HLA molecule. The crystallization of the T-cell receptor molecule, an experiment currently underway, will eventually reveal the structural basis of the trimolecular interaction.  相似文献   
14.
Early to mid-term fetuses heal cutaneous incisional wounds without scars; however, fetal response to burn injury has not been ascertained. We present a fetal model of thermal injury and subsequent analysis of fetal and lamb response to burn injury. A reproducible deep dermal burn injury was created in the fetus by application of water at 66 degrees C for 7 seconds, and at 82 degrees C for 10 seconds to the lamb. Macroscopically, the area of fetal scald was undetectable from day 7 post injury, while all lamb scalds were readily identified and eventually healed with scarring. Using a five-point histopathology scoring system for alteration in tissue morphology, differences were detected between control and scalded skin at all stages in lamb postburn, but no difference was detected in the fetal model after day 7. There were also large differences in content of alpha-smooth muscle actin and transforming growth factor-beta1 between control and scalded lamb and these differences were statistically significant at day 14 (P < 0.01). This novel model of fetal and lamb response to deep dermal injury indicates that the fetus heals a deep burn injury in a scarless fashion. Further elucidation of this specific fetal process of burn injury repair may lead to improved outcome for patients with burn injury.  相似文献   
15.
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.  相似文献   
16.
We report a case of congenital fistula from ectopic accessory parotid gland to the cheek demonstrated by CT sialography and CT fistulography. The right parotid gland was abnormally located lateral to masseter muscle. The fistula was arising from an ectopic accessory parotid gland with ectopic duct positioned anterior to masseter muscle. CT sialography and CT fistulography were very helpful in the diagnosis and surgical planning.  相似文献   
17.
18.
19.
Menstrual cycle and appetite control: implications for weight regulation   总被引:1,自引:0,他引:1  
Hormonal fluctuations associated with the menstrual cycle influence appetite control and eating behaviour. Energy intake varies during the reproductive cycle in humans and animals, with a periovulatory nadir and a luteal phase peak. Patterns of macronutrient selection show less consistency but a number of studies report carbohydrate cravings in the premenstrual phase, particularly in women with premenstrual syndrome. The cyclical nature of food cravings are frequently, but not invariably, associated with depression. Fluctuations in appetite, cravings and energy intake during the menstrual cycle may occur in parallel with cyclical rhythms in serotonin, which can be accompanied by affective symptoms. The premenstrual phase can be considered as a time when women are especially vulnerable to overconsumption, food craving and depression; this is often associated with low serotonin activity.   相似文献   
20.
Lee HH  Cha SC  Jang DJ  Lee JK  Choo DW  Kim YS  Uh HS  Kim SY 《Virus genes》2002,25(2):179-188
The immunity of a combined DNA vaccine of HSV-2 glycoproteins B2 (gB2) and D2 (gD2) genes in comparison to individual vaccines was studied with regard to protecting against the HSV infection. Two recombinant DNA vaccines of the pHS2-gB2 or pHS2-gD2 were constructed and formulated. The neutralizing antibody titers appeared higher in the B2:D2 gene cocktail-vaccinated mice than that of the individual B2 or D2 gene-vaccinated group alone, and the positive KOS control induced higher titer of the neutralizing antibody than combined or individual gene vaccines. The mock-immunized mice failed to induce enough. The ranks for the CTL activity and the protection rates against the lethal intravaginal challenge were shown as KOS>B2:D2 cocktail>D2>B2 gene vaccines. The vaginal external diseases in the B2:D2 or D-vaccinated mice were significantly reduced against the challenging dosages. The virus titers in the vaginal secretions of the vaccinated mice significantly reduced with time, and the B2:D2 gene vaccine decreased more than each individual vaccine alone. It can be concluded that the cocktailed vaccines are more effective in the humoral and cellular immune responses in the mice, and in the protection of the mice against the intravaginal challenging dosages when compared with individual gene vaccines. All the DNA vaccines failed to block the latent infection in sensory nerves.  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