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   1697654篇
  免费   123880篇
  国内免费   3788篇
耳鼻咽喉   21738篇
儿科学   55718篇
妇产科学   46210篇
基础医学   241574篇
口腔科学   48750篇
临床医学   151647篇
内科学   333993篇
皮肤病学   38710篇
神经病学   131350篇
特种医学   63955篇
外国民族医学   249篇
外科学   257569篇
综合类   38966篇
现状与发展   4篇
一般理论   532篇
预防医学   124391篇
眼科学   40310篇
药学   123731篇
  7篇
中国医学   4481篇
肿瘤学   101437篇
  2021年   12835篇
  2019年   13565篇
  2018年   20004篇
  2017年   15251篇
  2016年   16656篇
  2015年   18989篇
  2014年   26263篇
  2013年   38027篇
  2012年   52868篇
  2011年   55561篇
  2010年   32837篇
  2009年   30750篇
  2008年   51620篇
  2007年   54916篇
  2006年   55380篇
  2005年   52660篇
  2004年   50848篇
  2003年   48218篇
  2002年   46444篇
  2001年   91853篇
  2000年   93641篇
  1999年   76999篇
  1998年   19735篇
  1997年   17288篇
  1996年   17407篇
  1995年   16760篇
  1994年   15302篇
  1993年   14086篇
  1992年   57446篇
  1991年   55322篇
  1990年   53010篇
  1989年   50797篇
  1988年   46179篇
  1987年   44977篇
  1986年   42266篇
  1985年   40037篇
  1984年   29384篇
  1983年   24940篇
  1982年   13917篇
  1979年   25568篇
  1978年   17601篇
  1977年   14922篇
  1976年   13899篇
  1975年   14574篇
  1974年   17652篇
  1973年   16967篇
  1972年   15700篇
  1971年   14476篇
  1970年   13452篇
  1969年   12526篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
73.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
74.
75.
We report a case of cervical necrotizing fasciitis (CNF) in a female having uncontrolled type II diabetes mellitus. The patient was presented to us after 20 days of preliminary symptoms. The aetiology of microbial inoculation in subdermal tissue was not known. The isolate was Staphylococcus aureus. In spite of the delay in presentation, the patient was successfully treated with combined antimicrobial and surgical intervention.  相似文献   
76.
77.
Priori  A.  Cogiamanian  F.  Mrakic-Sposta  S. 《Neurological sciences》2006,27(4):s307-s309
Neurological Sciences - Spasticity arises from lesions involving the corticoreticulospinal system in the brain, brainstem or spinal cord. Abnormal suprasegmental influences lead to increased spinal...  相似文献   
78.
Group A streptococcal meningitis is less common than other forms of meningitis; however, the occurrence of this infection is associated with high mortality and morbidity. Early recognition and a prompt treatment are therefore essential. We review one case of an Asian women admitted with group A streptococcal meningitis as a complication of otitis media.  相似文献   
79.
The organophosphorous nerve agent sarin (GB) and the carbamate pyridostigmine bromide (PB) both inhibit acetylcholinesterase (AChE), leading to overstimulation of muscarinic receptors. Both GB and PB produce miosis through stimulation of ocular muscarinic receptors. This study investigated 2 hypotheses: (1) that the miotic response to PB would decrease following repeated injections; and (2) that repeated administration of PB would result in tolerance to the miotic effect of GB vapor. Rats were injected intramuscularly with saline, 0.04 mg/kg, 0.5 mg/kg, or 1.4 mg/kg of PB twice daily for 8 consecutive days. After day 3, animals injected with 1.4 mg/kg PB developed miotic tolerance. Twenty-four (24) h following the final PB injection, the rats were exposed to GB vapor (4.0 mg/m(3)). A similar magnitude of miosis was observed in all groups after GB exposure. However, the rate of recovery of pupil size in animals pretreated with 0.5 and 1.4 mg/kg PB was significantly increased. Twenty (20) h following exposure to GB vapor, the pupils of animals pretreated with 1.4 mg/kg PB had recovered to 77% +/- 4% of their pre-exposure baseline, whereas the saline-injected controls had recovered to only 52% +/- 2% of their pre-exposure baseline. The increased rate of recovery does not appear to be a result of protection of pupillary muscarinic receptors by the higher doses of PB, as there was no longer PB present in the animal at the time of GB exposure. These results demonstrate the development of tolerance to the miotic effect of PB following repeated exposures, and also suggest that cross-tolerance between PB and GB occurs. However, because the magnitude of the response was not reduced, the PB pretreatment and its associated miotic cross-tolerance does not appear to diminish the effectiveness of miosis as a biomarker of acute exposure to nerve agent vapor.  相似文献   
80.
Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision.  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