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   50603篇
  免费   2602篇
  国内免费   178篇
耳鼻咽喉   622篇
儿科学   1084篇
妇产科学   748篇
基础医学   7716篇
口腔科学   1351篇
临床医学   4385篇
内科学   10976篇
皮肤病学   1214篇
神经病学   5234篇
特种医学   2893篇
外国民族医学   23篇
外科学   7053篇
综合类   237篇
一般理论   20篇
预防医学   2364篇
眼科学   941篇
药学   3287篇
中国医学   69篇
肿瘤学   3166篇
  2023年   345篇
  2022年   493篇
  2021年   930篇
  2020年   604篇
  2019年   845篇
  2018年   1072篇
  2017年   854篇
  2016年   1214篇
  2015年   1383篇
  2014年   1617篇
  2013年   2089篇
  2012年   3337篇
  2011年   3364篇
  2010年   1985篇
  2009年   1727篇
  2008年   2962篇
  2007年   3055篇
  2006年   3001篇
  2005年   2849篇
  2004年   2525篇
  2003年   2407篇
  2002年   2288篇
  2001年   1019篇
  2000年   1050篇
  1999年   972篇
  1998年   502篇
  1997年   367篇
  1996年   289篇
  1995年   247篇
  1994年   216篇
  1993年   172篇
  1992年   395篇
  1991年   415篇
  1990年   389篇
  1989年   366篇
  1988年   297篇
  1987年   299篇
  1986年   259篇
  1985年   264篇
  1984年   207篇
  1983年   150篇
  1982年   151篇
  1979年   199篇
  1978年   149篇
  1977年   139篇
  1975年   171篇
  1974年   151篇
  1973年   164篇
  1972年   154篇
  1971年   137篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
71.
In the period between September 1990 and July 1991, 35 patients (46 eyes) were treated with the Excimer Laser. In 25 patients (34 eyes), a Myopia-Laser-Shaping was performed, one patient was treated for both myopia and astigmatism. In eight patients (10 eyes) correction of astigmatism was carried out. Two patients with recurrent erosions and one patient with superficial scarring of the cornea were treated. The authors review their initial experience with the Excimer Laser. The decision to initiate treatment must not be undertaken lightly, because the possibility of serious complications may not be neglected. This method shows promise in selected patients with light to medium degrees of myopia. In cases of severe myopia, our experience is encouraging. Subjectively, the patients are satisfied with the results, which do not fall short of their expectations. Further research and clinical experience in this area is urgently required.  相似文献   
72.
Das ambulante Operieren bringt neben finanzieller Entlastung der Kostenträger zweifelsohne eine Reihe von Vorteilen, aber auch Nachteile für die Patienten mit sich. Neben intensiven Anstrengungen zur Qualitätssicherung muss insbesondere die Diskussion über die Auswahl geeigneter Patienten für geeignete Eingriffe intensiv und kontinuierlich geführt werden. Dem Trend, das Spektrum ambulant durchgeführter Eingriffe auf ein immer stärker risikotragendes Patientengut auszudehnen, muss insgesamt zunächst mit Skepsis begegnet werden. Auch wenn mit den Fortschritten der Operationstechniken das operative Zugangstrauma erheblich reduziert werden kann und moderne Anästhesieverfahren eine sehr gute Steuerung der Patienten erlauben, stellt die Beherrschung der Komplikationen und Probleme der postoperativen Phase umso mehr besondere Herausforderungen sowohl an die ambulant operierenden Ärzte, Anästhesisten und Chirurgen als auch an die Patienten und mitbetreuenden Angehörigen.  相似文献   
73.
BACKGROUND: Food allergy to cherry occurs throughout Europe, typically with restricted oral reactions in the central and northern parts but with frequent systemic reactions in the Mediterranean region. Previous studies have demonstrated insufficient sensitivity of commercially available cherry extract reagents in the diagnosis of cherry allergy. OBJECTIVE: To assess the diagnostic performance of specific IgE tests based on recombinant cherry allergens in comparison with an extract-based assay and to skin prick test (SPT). A secondary objective was to analyse the frequency of systemic reactions in cherry-allergic subjects across Europe, including the largest population of LTP-sensitized subjects from central Europe studied to date. METHODS: A total of 186 subjects from central Europe and Spain were studied. Serum IgE was analysed with ImmunoCAP tests carrying rPru av 1, 3 and 4, combined and separately, and cherry extract. RESULTS: Among the central European cherry allergics, the mix of rPru av 1, 3 and 4 had a sensitivity of 95%, compared with 65% for cherry extract, and the IgE binding capacity of the recombinant mix was considerably higher. The sensitivity of the two tests was more comparable in the Spanish population, 95% and 86%, respectively. The recombinant allergen ImmunoCAP equalled SPT in terms of sensitivity and specificity. Consistent with previous reports, major geographic differences in sensitization pattern and prevalence of systemic reactions were found. A significantly higher rate of systemic reactions was found in Spanish patients sensitized to Pru av 3 whereas German patients sensitized to LTP only had oral allergy syndrome. CONCLUSIONS: The recombinant cherry allergen ImmunoCAP is a highly sensitive diagnostic tool, clearly superior to any diagnostic method based on cherry extract. Three cherry allergens are sufficient for detecting sensitization in 95% of cherry-allergic subjects. Systemic reactions are common in LTP-sensitized individuals but seem to require at least one additional causative factor.  相似文献   
74.
Microscopic colitis (MC) encompasses the two morphologically distinct entities of collagenous colitis (CC) and lymphocytic colitis (LC). MC was first described less than 30 years ago but is presently recognized as a relatively common cause of chronic diarrhea in the adult population. Remarkably, up to 10% of adults who have a colonoscopy for the investigation of chronic diarrhea, and have endoscopically normal appearing mucosa, may have MC. Patients with MC generally present with chronic diarrhea, which can be associated with cramping and bloating. Endoscopic and radiological examinations are usually normal. Histological assessment reveals inflammation consisting predominantly of lymphocytic infiltration, and a thickened subepithelial collagen band is diagnostic of CC. Both LC and CC can be associated with autoimmune diseases such as celiac disease, diabetes, arthritis and thyroiditis, yet the mechanisms involved in the pathogenesis remain unclear. Emerging studies suggest that a stepwise approach be taken in the medical management of MC. This approach includes antidiarrheal agents and stopping of any offending agents; budesonide or bismuth subsalicylate; and cholestyramine or 5-acetylsalicylic acid agents. In resistant cases, oral corticosteroids and other immune modulatory therapy have been used.  相似文献   
75.
76.
Abstract Background: In recent years, biomaterials are being found and frequently utilized in bone defects. They have also gained significant precedence in hand surgery. Objectives: The respective requirements for such replacement material will be cited and acknowledged in this article. The individual material groups will also be referred to in this review. An introduction to some of the customary bone replacement materials will be cited and concluded with a corresponding recommendation. Conclusion: The implantation of autologous cancellous bone is still regarded today as the “gold standard”. Nevertheless, the usage of bone replacement material can be an enormous advantage in certain indications. The original article can be found online at There was an error in the author’s affiliation and the address for correspondence was incomplete. Please note the correct institution and complete address: Department of Orthopedics and Traumatology, Hand-, Foot- and Reconstructive Surgery, Kreiskrankenhaus Gummersbach GmbH, Germany. Alexander von Friesen, MD Department of Orthopedics and Traumatology, Hand-, Foot- and Reconstructive Surgery Kreiskrankenhaus Gummersbach GmbH Wilhelm-Breckow-Allee 20 51643 Gummersbach Germany Phone (+49/2261) 171-575, Fax -449 e-mail: Friesen@kkh-gummersbach.de  相似文献   
77.
Hepatitis B virus (HBV) DNA is detectable in a number of liver transplant candidates who are negative for hepatitis B surface antigen (HBsAg). After liver transplantation (LT), such patients may have molecular and/or serologic evidence of HBV replication. However, clinical disease from reactivation of occult HBV infection after LT has not been described. We report a patient who underwent LT for cryptogenic cirrhosis and had to be retransplanted twice for hepatic artery thrombosis. The patient was negative for HBsAg and positive for anti-hepatitis B core (HBc) and anti-HBs before all LT procedures and developed acute hepatitis B shortly after receiving the third graft. The HBV strain isolated at that time exhibited an unusual in frame insertion of a CAG motif within the HBV polymerase (HBV(INS+)). HBV(INS+) was detected retrospectively as a minor species in pretransplantation sera and the explanted native liver by insertion-specific polymerase chain reaction. This case in an occult HBV carrier shows that clinically apparent, endogenous reinfection of the graft may occur with minor HBV variants that are not detectable in pretransplantation samples by standard diagnostic procedures. This has implications for the analysis of sources of acute hepatitis B in patients after LT and possibly for consideration of antiviral prophylaxis in anti-HBc/anti-HBs/HBV DNA-positive patients.  相似文献   
78.
79.
The aim of this study was to compare the efficacy and safety of a monomethoxypolyethylene glycol (mPEG) modified grass pollen mix allergen preparation (mPEG-gm) and a partly purified grass pollen mix allergen preparation (gm) in hyposensitization (HS), evaluating both products at two dose levels. Thirty adult patients with allergic rhinoconjunctivitis were allocated into two treatment groups based on their sensitivity to conjunctival provocation tests (CPT). Treatment was given in a double-blind manner. The starting dose was 20 BU and was approximately doubled weekly up to 20,000 BU the first year and 120,000 BU the second year. Skin testing and CPT were performed before treatment and at each dose level. All patients reached 20,000 BU the first year. Twenty-five patients continued the second year. Twenty-one of those reached 120,000 BU (9/12 on mPEG-gm and 12/13 on gm). The frequency of general side effects was reduced by about 50% with the mPEG grass mix compared with native grass mix. A significant improvement in the conjunctival sensitivity was found in both treatment groups the second year (120,000 BU) but not the first year (20,000 BU). Seventy-eight percent of the patients in the gm group and 50% in the mPEG-gm group improved by CPT (not statistically significant). The skin sensitivity was reduced after 1 year at low dose in 69% of the gm-treated patients and 33% of the mPEG treated patients. After the second year at high dose levels, the skin sensitivity decreased in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
80.
Plasma levels of the beta-carboline, abecarnil (isopropyl 6-(benzyloxy)-4-(methoxymethyl)-9H-pyrido [3,4-b]indole-3- carboxylate, ZK112119) which is presently under development as an anxiolytic, were measured by HPLC with fluorescence detection in six healthy male volunteers given 30 micrograms/kg i.v. and 5 and 10 mg p.o. Following i.v. injection, plasma levels declined biphasically with half-lives of 6 min and 3.4 h. The total clearance was 13 ml/min/kg. After oral administration, maximum concentrations were reached after 2 h. The bioavailability was approximately 60%. The terminal half-life after p.o. administration was 7 h. No clinically relevant changes in ECG, vital signs or standard laboratory measurements occurred. Eight different adverse reactions were noted by the subjects. The most frequently reported side-effects were tiredness, dizziness, unsteady gait and lack of concentration.  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