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   14288篇
  免费   921篇
  国内免费   14篇
耳鼻咽喉   342篇
儿科学   531篇
妇产科学   573篇
基础医学   1496篇
口腔科学   284篇
临床医学   1168篇
内科学   2761篇
皮肤病学   395篇
神经病学   1026篇
特种医学   842篇
外国民族医学   1篇
外科学   2896篇
综合类   198篇
一般理论   3篇
预防医学   925篇
眼科学   386篇
药学   703篇
中国医学   10篇
肿瘤学   683篇
  2021年   108篇
  2020年   64篇
  2019年   111篇
  2018年   140篇
  2017年   114篇
  2016年   106篇
  2015年   607篇
  2014年   714篇
  2013年   780篇
  2012年   873篇
  2011年   861篇
  2010年   750篇
  2009年   687篇
  2008年   851篇
  2007年   815篇
  2006年   784篇
  2005年   711篇
  2004年   554篇
  2003年   329篇
  2002年   270篇
  2001年   273篇
  2000年   270篇
  1999年   269篇
  1998年   150篇
  1997年   147篇
  1996年   123篇
  1995年   101篇
  1994年   105篇
  1993年   107篇
  1992年   229篇
  1991年   225篇
  1990年   237篇
  1989年   207篇
  1988年   181篇
  1987年   180篇
  1986年   153篇
  1985年   145篇
  1984年   130篇
  1983年   141篇
  1982年   85篇
  1981年   87篇
  1980年   67篇
  1979年   126篇
  1978年   84篇
  1977年   82篇
  1976年   104篇
  1975年   87篇
  1974年   83篇
  1973年   89篇
  1972年   86篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
Tyrosinemia type I is an autosomal recessive inherited defect of tyrosine metabolism. The underlying cause is a defect of fumarylacetoacetate hydrolase. The disease affects the liver (acute liver failure, liver cirrhosis, hepatocellular cancer), the kidney (tubulopathy with hypophosphatemic rickets), and the peripheral nervous system (paresthesia, vegetative symptoms, progressive paralysis). Beside the hypertyrosinemia the diagnosis can be made on the basis of urinary excretion of a pathological metabolite of the tyrosine metabolism (succinylacetone). Therapeutic options are a regulated phenylalanine/tyrosine diet, a very effective drug therapy (NTBC) that has been available for several years, and in cases of acute liver failure or end-stage liver cirrhosis a liver transplantation.  相似文献   
172.
Ohne Zusammenfassung  相似文献   
173.
In monochorionic twin pregnancies, the risk of developing a twin to twin transfusion syndrome is between 15 and 20%. Using high-resolution ultrasound machines, sonographic images demonstrate the detailed features of placental development. The lambda sign was established for the diagnosis of dichorionic placenta and the T sign for monochorionic placenta at the end of the first trimester. Other sonographic findings of the twin to twin transfusion syndrome are monochorionicity, same sex, polyhydramnios, permanently filled bladder in the recipient, and oligo/anhydramnios of the donor with a slightly filled or empty bladder. Fetoscopic laser treatment has become an accepted procedure to coagulate the placental anastomoses. This development is supported by actual studies about psycho- and neuromotoric development in early childhood, which shows a lower rate of disabled children in the group receiving laser therapy in comparison to the group undergoing amnioreduction. Twin pregnancies complicated by twin to twin transfusion syndrome should be treated in specialized prenatal centers.  相似文献   
174.
Pathological auditory brainstem responses (lack of responses, elevated thresholds and perturbed waveforms) in combination with present otoacoustic emissions are typical audiometric findings in patients with a hearing impairment that particularly affects speech comprehension or complete deafness. This heterogenous group of disorders first described as “auditory neuropathy” includes dysfunction of peripheral synaptic coding of sound by inner hair cells (synaptopathy) and/or of the generation and propagation of action potentials in the auditory nerve (neuropathy). This joint statement provides prevailing background information as well as recommendations on diagnosis and treatment. The statement focuses on the handling in the german language area but also refers to current international statements.  相似文献   
175.
Minimally invasive diagnostic procedures for the breast under mammography, ultrasound, and magnetic resonance guidance have led to a higher specificity of imaging techniques and a decrease in open biopsy of the breast. The percutaneous approach is more cost and time effective and reduces morbidity compared with open biopsy. The “Step-3-guideline for early breast cancer detection in Germany” represents the first national guidelines for a nationwide, quality assured, early breast cancer detection program, including recommendations for minimally invasive breast diagnostics. Indications for ultrasound guided vacuum biopsy of the breast are summarized in the “Consensus on the use and technique of vacuum-assisted sonographic breast biopsy” by the Study Group on Minimally Invasive Breast Interventions (AG MiMi) of the German Society of Senology (DGS).  相似文献   
176.
BACKGROUND: Dye-directed sentinel node biopsy (SNB) for breast cancer provides accurate staging with low morbidity, but for tumors distant from the axilla, its use has been questioned. HYPOTHESIS: Can preoperative breast lymphoscintigraphy (BL) applied selectively to medial hemisphere tumors predict a subset of patients who may not require surgical staging of the axilla? DESIGN: Prospective cohort study. SETTING: Tertiary, multidisciplinary breast center. PATIENTS: Thirty-two women with breast tumors located in the medial hemisphere (30) or inframammary crease (2). INTERVENTION: Peritumoral injection of 500 microCi of technetium Tc 99m sulfur colloid and biplanar imaging. Nonpalpable lesions were localized with ultrasound or mammography. At the time of definitive breast surgery, isosulfan blue dye-directed SNB was performed. Axillary dissection was performed when the SN contained a tumor or could not be identified. MAIN OUTCOME MEASURES: Regional nodal basins identified by BL; success rate of SNB. RESULTS: Preoperative BL demonstrated axillary drainage in 28 patients (88%); 2 patients (6%) had isolated internal mammary radionuclide uptake, and 2 patients had no nodal uptake. Dye-directed axillary SNB succeeded in 27 (87%) of 31 patients, including both patients with failed BL. Breast lymphoscintigraphy had predicted isolated internal mammary drainage in 2 of 4 patients whose SNs could not be identified. Metastases were found in 5 patients (16%). CONCLUSIONS: Axillary radionuclide uptake predicts but does not augment dye-directed SN identification. In those few patients with isolated internal mammary drainage, BL may obviate the need for surgical staging of the axilla.  相似文献   
177.
PURPOSE: In this multicenter, randomized, placebo-controlled clinical trial, we studied whether warfarin 1 mg daily reduces the incidence of symptomatic central venous catheter (CVC) -associated thrombosis in patients with cancer. PATIENTS AND METHODS: Two hundred fifty-five patients with cancer who required a CVC for at least 7 days were randomly assigned to receive warfarin 1 mg or placebo. RESULTS: There were 11 (4.3%) symptomatic CVC-associated thromboses among 255 patients, with no difference in the incidence of symptomatic CVC-associated thrombosis between patients taking warfarin 1 mg daily (six of 130 patients; 4.6%) and patients taking placebo (five of 125 patients; 4.0%; hazard ratio, 1.20; 95% CI, 0.37 to 3.94). Warfarin had no effect on CVC life span (84 days v 63 days in control and warfarin groups, respectively; 95% confidence limit, -16 to 55 days; P = .09), and it did not affect the number of premature CVC removals (23.2% v 25.4% in control and warfarin groups, respectively; 95% confidence limit of difference -8.34 to 12.71; P = .68) or the frequency of major bleeding episodes (2% v 0% in control and warfarin groups, respectively; P = .5, Fisher's exact test). CONCLUSION: Symptomatic CVC-associated thrombosis in patients with cancer, although significant, is less common than previously reported. In this study, the administration of warfarin 1 mg daily did not reduce the incidence of symptomatic CVC-associated thrombosis in patients with cancer. However, the low rate of symptomatic CVC-associated thrombosis means that a much larger trial is required to address this issue definitively.  相似文献   
178.
Zusammenfassung Multimodale Therapiestrategien, die Chirurgie, Strahlen- und Chemotherapie kombinieren, haben die Behandlungsergebnisse bei Tumoren der Lunge und der Kopf-Hals Region verbessert. Die Ergänzung des Therapiespektrums um weitere Ansätze, die sich in der Wirkungsweise und möglichst durch reduzierte Toxizität von den konventionellen unterscheiden, erscheint jedoch zur Erzielung weiterer Fortschritte notwendig. Eine neue Generation immunologischer passiver (antikörperbasierter) und auch aktiver (Vakzinierungs-) Strategien erscheint aussichtsreich und befindet sich gegenwärtig in der klinischen Prüfung. Die Untersuchung der optimalen zeitlichen Sequenz in Kombination mit den konventionellen Therapieverfahren und die Individualisierung der Therapie auf Basis genomischer/proteomischer Daten muss die klinische Integration begleiten.  相似文献   
179.
The aim of treatment in isolated locally recurrent rectal cancer is R0 resection, which is possible in 30%. Because of the high rate of surgical complications after repeat surgery in the pelvis, preoperative staging has to be precise to estimate the extent and location of the recurrent rectal cancer. After exclusion of distant metastases, surgery should be considered following preoperative radiochemotherapy if possible. When a curative treatment concept is not indicated, radiotherapy is the best treatment choice. This paper presents various tabularised summaries about therapeutic strategies in isolated locally recurrent rectal cancer.  相似文献   
180.
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