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   181728篇
  免费   1208篇
  国内免费   47篇
耳鼻咽喉   1176篇
儿科学   6821篇
妇产科学   3123篇
基础医学   17298篇
口腔科学   1676篇
临床医学   12744篇
内科学   32220篇
皮肤病学   780篇
神经病学   16750篇
特种医学   9168篇
外科学   29896篇
综合类   2341篇
预防医学   18205篇
眼科学   2909篇
药学   10082篇
中国医学   676篇
肿瘤学   17118篇
  2023年   38篇
  2021年   166篇
  2020年   93篇
  2019年   152篇
  2018年   22057篇
  2017年   17459篇
  2016年   19637篇
  2015年   1054篇
  2014年   977篇
  2013年   970篇
  2012年   7241篇
  2011年   21330篇
  2010年   18986篇
  2009年   11647篇
  2008年   19730篇
  2007年   21979篇
  2006年   831篇
  2005年   2497篇
  2004年   3693篇
  2003年   4615篇
  2002年   2770篇
  2001年   470篇
  2000年   618篇
  1999年   358篇
  1998年   251篇
  1997年   276篇
  1996年   145篇
  1995年   164篇
  1994年   136篇
  1993年   97篇
  1992年   173篇
  1991年   202篇
  1990年   262篇
  1989年   195篇
  1988年   166篇
  1987年   151篇
  1986年   144篇
  1985年   110篇
  1984年   103篇
  1983年   80篇
  1982年   51篇
  1980年   59篇
  1979年   59篇
  1974年   47篇
  1970年   56篇
  1969年   39篇
  1968年   40篇
  1938年   60篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
991.
Proteus syndrome is a rare, sporadic, hamartomatous disorder manifesting with multifocal overgrowth of tissue. The features seem to develop most often during childhood. Vertebral overgrowth with severe spinal canal stenosis is unusual, although scoliosis with abnormal vertebral bodies is one of the typical features of Proteus syndrome. We report a case of Proteus syndrome with severe spinal canal stenosis, scoliosis, cervical kyphosis, and thoracic deformity with airway obstruction because of asymmetrical overgrowth of vertebrae and ribs associated with a tethered cord, lipomas, strawberry hemangioma, flat nasal bridge, and bilateral hypoplasty of the first metatarsal bones with hyperplasty of soft tissue.  相似文献   
992.
This study aimed to analyze and classify the clinical features of headache in neurological outpatients. A cross-sectional study was conducted consecutively from March to May 2010 for headache among general neurological outpatients attending the First Affiliated Hospital of Chongqing Medical University. Personal interviews were carried out and a questionnaire was used to collect medical records. Diagnosis of headache was according to the International classification of headache disorders, 2nd edition (ICHD-II). Headache patients accounted for 19.5% of the general neurology clinic outpatients. A total of 843 (50.1%) patients were defined as having primary headache, 454 (27%) secondary headache, and 386 (23%) headache not otherwise specified (headache NOS). For primary headache, 401 (23.8%) had migraine, 399 (23.7%) tension-type headache (TTH), 8 (0.5%) cluster headache and 35 (2.1%) other headache types. Overall, migraine patients suffered (1) more severe headache intensity, (2) longer than 6 years of headache history and (3) more common analgesic medications use than TTH ones (p < 0.001).TTH patients had more frequent episodes of headaches than migraine patients, and typically headache frequency exceeded 15 days/month (p < 0.001); 22.8% of primary headache patients were defined as chronic daily headache. Almost 20% of outpatient visits to the general neurology department were of headache patients, predominantly primary headache of migraine and TTH. In outpatient headaches, more attention should be given to headache intensity and duration of headache history for migraine patients, while more attention to headache frequency should be given for the TTH ones.  相似文献   
993.
994.

Purpose  

To evaluate the safety and efficacy of n-butyl cyanoacrylate (NBCA) injection under fluoroscopy for iatrogenic femoral artery pseudoaneurysms under temporary balloon occlusion.  相似文献   
995.

Purpose  

To determine cellular viability of lung parenchyma and neoplastic cells in areas of ground-glass opacity (GGO) on computed tomography (CT) images immediately after pulmonary radiofrequency ablation (RFA) in rabbits.  相似文献   
996.
Castleman disease (CD) is a rare lymphoproliferative disorder. Two clinical entities are described: a unicentric form with disease confined to a single lymph node region and a multicentric form characterized by generalized lymphadenopathy and systemic symptoms. Although surgery is regarded as standard therapy for the unicentric form, no consensus has been reached concerning the standard treatment for multicentric CD. We report here a case of cervical multicentric CD treated with intensity-modulated radiation therapy (IMRT), using helical tomotherapy to minimize xerostomia in comparison with conventional radiotherapy. A 29-year-old woman complained of neck swelling. Computed tomography showed lymphadenopathy in both sides of the neck. The patient was diagnosed with the plasma cell subtype of CD on biopsy. After initial treatment with prednisone, IMRT was planned to avoid normal structures, for example the parotid gland. The cervical lymphadenopathy shrank gradually during IMRT with 44 Gy in 22 fractions. Four years and 3 months after IMRT, regrowth of cervical lymph nodes has not been detected. The parotid function improved dramatically on quantitative salivary scintigraphy between 3 and 12 months after IMRT. Radiotherapy could be an option for multicentric CD, and IMRT is an effective means of minimizing xerostomia in head and neck lesions.  相似文献   
997.
This case report involves a 60-year-old diabetic man who developed septic arthritis as a result of the pathogen Morganella morganii. The patient had complaints of elevated body temperature, malaise, rigors and pain in the left knee, despite no history of trauma. On examination of the knee, erythema, warmth, tenderness and swelling was observed. Arthrocentesis performed on his left knee indicated the presence of straw-coloured, cloudy fluid without crystals. Bacterial identification based on biochemical and automated methods indicated the growth of M morganii. M morganii was also isolated sedimentafrom the exudate of a diabetic ulcer in the left foot, with antibiotic susceptibilities identical to those from the knee effusion. This case indicates that M morganii may be considered as a possible cause of septic arthritis in diabetic patients, especially those with diabetic foot infections.  相似文献   
998.
Positron emission tomography (PET) using l-[methyl-11C]-methionine (MET) is the most popular amino acid imaging modality in oncology, although its use is restricted to PET centers with an in-house cyclotron facility. This review focuses on the role of MET–PET in imaging of cerebral gliomas. The biological background of tumor imaging with methionine is discussed with particular emphasis on cellular amino acid transport, amino acid utilization in brain, normal metabolism of methionine, and its alterations in cancer. The role of MET–PET in clinical management of cerebral gliomas in initial diagnosis, differentiation of tumor recurrence from radiation injury, grading, prognostication, tumor-extent delineation, biopsy planning, surgical resection and radiotherapy planning, and assessment of response to therapy is also reviewed in detail.  相似文献   
999.

Purpose

The aim of this study was to elucidate the distribution of estimated glomerular filtration rate (eGFR) values in patients who underwent gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance imaging (MRI) at different types of hospitals.

Materials and methods

We retrospectively studied 2,550 patients who underwent MRI at five institutions. We recorded the date and value of each patient??s eGFR test. The distribution of eGFR values was compared with that in the general Japanese population.

Results

A total of 84.3% of patients had their eGFRs evaluated before GBCA-enhanced MRI. Of these, 84.7% were evaluated within 3?months before the GBCA-enhanced MRI, and 1.3% were evaluated on the day of the GBCA-enhanced MRI. A total of 87.2% of patients tested had an eGFR of ??60?ml/min/1.73?m2; 12.8% had an eGFR of <60 and ??30?ml/min/1.73?m2, and no patients had an eGFR of <30?ml/min/1.73?m2.

Conclusion

The rate of renal function evaluation differed among hospitals. The prevalence of low eGFR values was greater in Juntendo Tokyo Koto Geriatric Medical Center than in the other hospitals, and the prevalence of low eGFR values was greater in patients who underwent GBCA-enhanced MRI than in the general Japanese population.  相似文献   
1000.
Patients with coronary artery calcium (CAC) scores of zero are generally considered not to have atherosclerosis. Recent studies involving computed tomography coronary angiography (CTCA) challenge this assumption. This goal of the present study is to assess the frequency, morphology, location, and the prognosis of patients with plaque detected on CTCA and zero CAC. 1,119 patients (51 ± 12 years, 52% male) with a zero CAC score during CTCA study were retrospectively identified. The CTCA studies were assessed for the presence, morphology, location and severity of all coronary plaques. All-cause mortality was assessed. The prevalence of coronary plaque was 13% (147 patients). Among the 212 plaques identified 154 (73%) were non-calcified, 28 (13%) were calcified, and 30 (14%) were of mixed morphology. Notably, ≥70% stenosis was noted among only 0.4% of all patients. ROC analysis revealed that coronary artery disease risk factors did not add to the prediction of plaque among our patients. Over a mean follow-up of 2.5 ± 0.6 years there were 4 deaths (0.4%), all in patients without coronary plaque on CTCA. The presence of coronary plaque is not uncommon among patients with zero CAC scores. These plaques were rarely associated with hemodynamically significant stenoses and were associated with an excellent prognosis. Clinical factors do not appear to be useful in predicting which patients with zero CAC scores have undetected coronary plaque.  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