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   9180篇
  免费   403篇
  国内免费   60篇
耳鼻咽喉   84篇
儿科学   111篇
妇产科学   124篇
基础医学   1031篇
口腔科学   342篇
临床医学   545篇
内科学   2660篇
皮肤病学   93篇
神经病学   565篇
特种医学   290篇
外科学   1628篇
综合类   56篇
预防医学   232篇
眼科学   158篇
药学   796篇
中国医学   23篇
肿瘤学   905篇
  2022年   86篇
  2021年   199篇
  2020年   101篇
  2019年   132篇
  2018年   163篇
  2017年   138篇
  2016年   145篇
  2015年   136篇
  2014年   200篇
  2013年   244篇
  2012年   426篇
  2011年   417篇
  2010年   255篇
  2009年   178篇
  2008年   389篇
  2007年   444篇
  2006年   424篇
  2005年   439篇
  2004年   427篇
  2003年   377篇
  2002年   396篇
  2001年   262篇
  2000年   280篇
  1999年   268篇
  1998年   125篇
  1997年   98篇
  1996年   93篇
  1995年   88篇
  1994年   68篇
  1993年   57篇
  1992年   220篇
  1991年   178篇
  1990年   166篇
  1989年   195篇
  1988年   167篇
  1987年   163篇
  1986年   158篇
  1985年   153篇
  1984年   114篇
  1983年   101篇
  1982年   60篇
  1979年   78篇
  1978年   65篇
  1977年   61篇
  1976年   59篇
  1974年   58篇
  1973年   50篇
  1972年   52篇
  1970年   50篇
  1969年   71篇
排序方式: 共有9643条查询结果,搜索用时 15 毫秒
31.
Metastasis directly to the optic nerve head without choroidal involvement is rare. We report a case of metastatic adenocarcinoma of the optic nerve head and retina with vitreous seeds which was observed in a 45-year-old Japanese male. The primary site of the lesion was clinically the upper lobe of the left lung. Tumor emboli were observed in the central retinal vein. Vitreous seeds appeared to have arisen from a necrotic area and papillary projections of the tumor.  相似文献   
32.
A case of a bilateral pulmonary hernia of the lungs into the supraclavicular fossae is described. A man, aged 79, with severe chronic asthma and chronic bronchitis due to air pollution, complained of a cervical mass off and on for several years. The herniation was greater on the right side. It could be identified on physical examination by the presence of a soft painless supraclavicular bulge which was exaggerated by strain or cough. Radiologically this herniation could best be identified on lateral cervical roentgenogram. It is said that cervical lung hernia is a rare condition, but in our experience supraclavicular herniation of the lung is not unusual in cases of severe chronic obstructive lung disease.  相似文献   
33.
Summary The effectiveness of extracranial-intracranial arterial bypass (EC-IC bypass) surgery on impaired haemodynamic status was studied in 12 patients with reduced regional cerebral perfusion pressure (rCPP) and elevated regional oxygen extraction fraction (rOEF) in the area distal to the symptomatic arterial lesion. Postoperative positron emission tomography (PET) study demonstrated a statistically significant decrease of rOEF in the operated hemispheres with disappearance of the pre-operative interhemispheric rOEF difference. Regional cerebral blood flow (rCBF) and regional cerebral oxygen metabolism (rCMRO2) were also increased in the operated hemispheres with disappearance of the pre-operative interhemispheric differences. Regional CBF/regional cerebral blood volume (rCBV) ratios of the symptomatic hemispheres were increased after surgery, but were still lower than in the contralateral hemispheres. We conclude that EC-IC bypass surgery improves impaired cerebral oxygen metabolic reserve.  相似文献   
34.
35.
Selenium (Se) is not routinely included in total parenteral nutrition (TPN) solution; thus, patients receiving long-term TPN may be at risk of Se deficiency, which may cause fatal cardiomyopathy. Platelet glutathione peroxidase (GSH-Px) activity, as well as Se levels and GSH-Px activity in plasma and erythrocytes during prolonged TPN, was measured in six patients with chronic gastrointestinal disease. During the time course of TPN, Se administration was discontinued for 12 weeks, and then resupplemented for another 12 weeks. Before the study period, all Se indices had been maintained within the normal range. After discontinuation of Se supplementation, a significant decrease in platelet GSH-Px activity was observed after 1 week (from 64 +/- 7 [mean +/- SD] to 39 +/- 5 U/g of protein). After resupplementation, it increased after 1 week (from 44 +/- 9 to 65 +/- 10 U/g of protein). Plasma Se indices significantly changed within 3 weeks after withdrawal and reintroduction of Se (Se: from 136 +/- 28 to 75 +/- 14 and from 61 +/- 22 to 125 +/- 33 micrograms/L; GSH-Px: from 236 +/- 50 to 140 +/- 36 and from 128 +/- 32 to 220 +/- 64 U/L). Erythrocyte Se indices showed no significant changes during the study period. The results demonstrate that platelet GSH-Px activity is the most sensitive index of Se status in TPN patients.  相似文献   
36.
To address the current role of liver transplantation (LT) for urea cycle disorders (UCDs), we reviewed the worldwide English literature on the outcomes of LT for UCD as well as 13 of our own cases of living donor liver transplantation (LDLT) for UCD. The total number of cases was 51, including our 13 cases. The overall cumulative patient survival rate is presumed to be more than 90% at 5 years. Most of the surviving patients under consideration are currently doing well with satisfactory quality of life. One advantage of LDLT over deceased donor liver transplantation (DDLT) is the opportunity to schedule surgery, which beneficially affects neurological consequences. Auxiliary partial orthotopic liver transplantation (APOLT) is no longer considered significant for the establishment of gene therapies or hepatocyte transplantation but plays a significant role in improving living liver donor safety; this is achieved by reducing the extent of the hepatectomy, which avoids right liver donation. Employing heterozygous carriers of the UCDs as donors in LDLT was generally acceptable. However, male hemizygotes with ornithine transcarbamylase deficiency (OTCD) must be excluded from donor candidacy because of the potential risk of sudden-onset fatal hyperammonemia. Given this possibility as well as the necessity of identifying heterozygotes for other disorders, enzymatic and/or genetic assays of the liver tissues in cases of UCDs are essential to elucidate the impact of using heterozygous carrier donors on the risk or safety of LDLT donor-recipient pairs. In conclusion, LT should be considered to be the definitive treatment for UCDs at this stage, although some issues remain unresolved.  相似文献   
37.
In seven patients undergoing right hemicolectomy for benign or malignant diseases, latero-lateral end anastomoses were made using stapling devices, LS (linear stapler) and GIA (gastrointestinal anastomosis). As no complications directly related to the anastomosis occurred, we conclude that anastomosis using stapling devices for right hemicolectomy is a safe and rapid procedure.  相似文献   
38.
The posterior choroidal artery supplies the lateral geniculate body, the posterior thalamus and the caudate body. Currently, a few cases of infarction in this arterial territory have been reported. This is a case of 59-year-old male, exhibiting left homonymous hemianopsia and left hemiparesis. Clinically it was impossible to make a diagnosis of infarction in this area. We were able to determine that it was a posterolateral choroidal artery infarction rather than an anterior choroidal artery infarction using 1.5 T-magnetic resonance imaging (MRI). The MRI scan clearly disclosed the areas of infarction, which included the lateral geniculate body, the posterior thalamus and the caudate nucleus body. Additionally, cerebral angiography revealed an occluded proximal portion of the right posterior cerebral artery (P2) and a patent right anterior choroidal artery. Anatomically, the areas surrounding the lateral geniculate body are supplied by both the anterior and the posterolateral choroidal arteries. However, the posterolateral choroidal artery infarctions are believed to be rare due to usual dominance of the anterior choroidal artery. Presently, with the use of MRI scanning, these areas can be easily visualized. Therefore, the posterolateral choroidal artery infarction can be diagnosed more easily. It is conceivable that more cases will be accurately diagnosed using this tool.  相似文献   
39.
40.
Three noninvasive image-diagnosing methods, computed tomography (CT), scintigraphy with201T1C1 and99mTcOh4 , and ultrasonography (US), were preoperatively performed on 50 patients with chronic renal failure and secondary hyperparathyroidism who underwent total parathyroidectomy and parathyroid autograft. The detection rates of the 3 methods on the 191 excised parathyroid glands were compared according to weight and location. CT detected 57.1% of all glands and 78.6% of 103 glands weighing over 500 mg. Scintigraphy detected 51.8% and 75.7%, and US detected 42.4% and 53.4%, respectively. The detection rate of upper glands was best with CT at 58.9% and 89.1%; that of lower glands was best with scintigraphy at 65.3% and 80.4%. Although the combination of the 3 methods diagnosed 69.6% and 89.5%, CT and scintigraphy, the best 2 combinations, visualized 67.5% and 88.3%.
Resumen Tres métodos diagnósticos no invasivos, la tomografía computadorizada (TC), la centelleografía con201T1C1 y99mTcO4 y la ultrasonografía (US) fueron realizados preoperatoriamente en 50 pacientes con falla renal crónica e hiperparatiroidismo secundario sometidos a paratiroidectomía y autotransplante paratiroideo. Las tasas de detección de los 3 métodos fueron comparados sobre las 191 glándulas paratiroideas resecadas en relación a los pesos y a los sitios de ubicación. La TC detectó el 57.1% del total de glándulas y el 78.6% de aquellas glándulas (103) con pesos superiores a 500 mg. La centelleografía detectó 51.8% y 75.7%, y la US 42.4% y 53.4% respectivamente. La tasa de detección para las glándulas superiores fue optima con TC, con 58.9% y 89.1%; la de las glándulas inferiores fue óptima con centelleografía, con 65.3% y 80.4%. Aunque la combinación de los 3 metodos diagnosticó el 69.6% y 89.5%, la TC y la centelleografía, la mejor de las combinaciones, visualizó el 67.5% y el 88.3% respectivamente.

Résumé Trois méthodes d'imagerie non invasives, la tomodensitométrie, la scintigraphie (avec T1C1210 et TcO4 99m), et l'ultrasonographie ont été pratiquées avant l'intervention chez 50 malades qui présentaient une insuffisance rénale chronique compliquée d'hyperparathyroïdisme secondaire et qui furent traités par parathyroïdectomie totale et autogreffe parathyroïdienne. Les taux de détection de ces 3 méthodes concernant 191 glandes parathyroïdes réséquées ont été évalués en fonction du poids et du siège des lésions. La tomodensitométrie a permis de découvrir 57.1% de toutes les glandes et 78.6% des glandes dont le poids dépassait 500 mg; la scintigraphie 51.8% et 75.7%; l'ultrasonographie 42.4% et 53.4%. Le taux de détection des glandes supérieures fut plus élevé avec la tomodensitométrie: 58.9% et 89.1%; celui des glandes inférieures le fut avec la scintigraphie: 65.3% et 80.4%. Si la combinaison des 3 méthodes permet le diagnostic dans 69.6% et 89.5% des cas la tomodensitométrie associée seulement à la scintigraphie donne des résultats très voisins, les taux respectifs étant de 67.5% et de 88.3%.


Presented at the International Association of Endocrine Surgeons in Paris, September 1985.  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