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   217015篇
  免费   3319篇
  国内免费   154篇
耳鼻咽喉   1705篇
儿科学   8998篇
妇产科学   3693篇
基础医学   21625篇
口腔科学   2675篇
临床医学   15368篇
内科学   38462篇
皮肤病学   1951篇
神经病学   18812篇
特种医学   10151篇
外科学   35008篇
综合类   3729篇
一般理论   20篇
预防医学   20225篇
眼科学   4399篇
药学   13508篇
  1篇
中国医学   997篇
肿瘤学   19161篇
  2023年   364篇
  2022年   1066篇
  2021年   1780篇
  2020年   987篇
  2019年   1072篇
  2018年   23071篇
  2017年   18148篇
  2016年   20643篇
  2015年   2317篇
  2014年   2882篇
  2013年   3160篇
  2012年   10239篇
  2011年   24037篇
  2010年   20576篇
  2009年   12914篇
  2008年   21546篇
  2007年   23794篇
  2006年   2637篇
  2005年   3981篇
  2004年   5033篇
  2003年   5765篇
  2002年   3745篇
  2001年   1132篇
  2000年   1233篇
  1999年   841篇
  1998年   510篇
  1997年   441篇
  1996年   333篇
  1995年   312篇
  1994年   258篇
  1993年   209篇
  1992年   459篇
  1991年   479篇
  1990年   548篇
  1989年   456篇
  1988年   386篇
  1987年   328篇
  1986年   300篇
  1985年   310篇
  1984年   234篇
  1983年   166篇
  1982年   101篇
  1981年   97篇
  1980年   123篇
  1979年   134篇
  1978年   101篇
  1977年   101篇
  1976年   84篇
  1974年   83篇
  1970年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
An ELISA technique has been developed to detect HBsAg in the sera of leprosy patients. Out of ninety-two serum samples taken from untreated leprosy patients, 10 samples were positive for HBsAg. The ELISA used in the present investigation is a low cost, reliable and sensitive marker of HBsAg. It is better than lesser sensitive (haemagglutination and counterimmunoelectrophoresis), costly and hazardous (radioimmunoassay) techniques and is therefore recommended for routine use.  相似文献   
103.
104.
105.
Abstract We report a case of SMV injury in a critically ill patient. The patient was a 19-year-old woman involved in a motor vehicle collision. Her injuries included grade II splenic and renal lacerations, devascularized and lacerated right and transverse colon, a transected transverse mesocolon, a massive shear injury of her abdominal wall, and two partial SMV transections. At initial damage control laparotomy, the SMV was ligated, the devascularized bowel resected and a temporary abdominal closure applied. At re-operation, a mesocaval shunt using saphenous vein was employed. The shunt failed and the patient required a saphenous vein jump graft. Although visceral vascular injuries are rare, ligation of the SMV in a damage control situation is acceptable. This case study is the first to discuss appropriate treatment when interruption to a patient's collateral visceral venous drainage limits the surgeon’s ability to ligate. In these situations, bypass shunts may be successful.  相似文献   
106.
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference.  相似文献   
107.
OBJECTIVES: This study sought to characterize epileptic phenotypes in children with nonspecific mitochondrial disease (MD) and to evaluate MD diagnostic approaches. METHODS: A retrospective analysis of the medical, electroencephalogram, and laboratory records of 142 patients with epilepsy was performed. The patients were evaluated for MD, and 124 patients were included in the final cohort. The MD criteria used included an oral glucose lactate stimulation test (OGLST) and urine organic acid/plasma amino acid (UOA/PAA) assays as metabolic indicators of modified Walker criteria, as suggested by Bernier et al. (Neurology 59:1406-1411, 2002). RESULTS: Twenty-two patients were classified as having definite MD (9), probable MD (5), possible MD (6), or pyruvate dehydrogenase (PDH) deficiency (3), including one patient which showed a respiratory chain (RC) defect and PDH deficiency. Seven out of eight patients in whom significant RC defects were observed showed complex I defects. In 14 patients, epileptic seizures start at infantile ages. Of 17 patients who substantially presented generalized seizures, 4 patients started with partial seizures. Five patients consistently presented only partial seizures. The OGLST and UOA/PAA assays were useful for a more precise diagnosis of MD, although low positive predictive value of the OGLST was regrettable. No patient was classified as definite MD by Walker's original criteria, but the use of our revised MD criteria resulted in the classification of nine additional patients as definite MD. CONCLUSIONS: MD manifested considerable diverse epileptic phenotypes and should be considered in the differential diagnosis of epilepsy in children with unexplained encephalomyopathy and progressive and fluctuating clinical courses.  相似文献   
108.
109.
Over the past 10 years, arteriography has become a well-established technique for the diagnosis of acute lower gastrointestinal bleeding, but not particularly for rectal bleeding. However, to the authors' knowledge, the technique of middle hemorrhoidal artery embolization has rarely been reported in the literature. In the present report, three patients with life-threatening rectal bleeding are presented, which was controlled by superselective embolization of the middle hemorrhoidal artery or selective embolization of the internal iliac artery as a last resort.  相似文献   
110.
Objective This study aims to question the generally accepted cerebrospinal fluid (CSF) bulk flow theory suggesting that the CSF is exclusively absorbed by the arachnoid villi and that the cause of hydrocephalus is a CSF absorption deficit. In addition, this study aims to briefly describe the new hydrodynamic concept of hydrocephalus and the rationale for endoscopic third ventriculostomy (ETV) in communicating hydrocephalus. Critique The bulk flow theory has proven incapable of explaining the pivotal mechanisms behind communicating hydrocephalus. Thus, the theory is unable to explain why the ventricles enlarge, why the CSF pressure remains normal and why some patients improve after ETV. Hydrodynamic concept of hydrocephalus Communicating hydrocephalus is caused by decreased intracranial compliance increasing the systolic pressure transmission into the brain parenchyma. The increased systolic pressure in the brain distends the brain towards the skull and simultaneously compresses the periventricular region of the brain against the ventricles. The final result is the predominant enlargement of the ventricles and narrowing of the subarachnoid space. The ETV reduces the increased systolic pressure in the brain simply by venting ventricular CSF through the stoma. The patent aqueduct in communicating hydrocephalus is too narrow to vent the CSF sufficiently.  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