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   1665篇
  免费   176篇
  国内免费   11篇
耳鼻咽喉   4篇
儿科学   126篇
妇产科学   24篇
基础医学   207篇
口腔科学   74篇
临床医学   248篇
内科学   383篇
皮肤病学   19篇
神经病学   50篇
特种医学   225篇
外科学   151篇
综合类   48篇
预防医学   142篇
眼科学   17篇
药学   71篇
  1篇
中国医学   1篇
肿瘤学   61篇
  2021年   17篇
  2020年   15篇
  2019年   16篇
  2018年   25篇
  2017年   27篇
  2016年   23篇
  2015年   31篇
  2014年   43篇
  2013年   31篇
  2012年   56篇
  2011年   49篇
  2010年   65篇
  2009年   66篇
  2008年   57篇
  2007年   39篇
  2006年   32篇
  2005年   34篇
  2004年   38篇
  2003年   38篇
  2002年   46篇
  2001年   40篇
  2000年   35篇
  1999年   36篇
  1998年   89篇
  1997年   90篇
  1996年   96篇
  1995年   67篇
  1994年   56篇
  1993年   58篇
  1992年   36篇
  1991年   35篇
  1990年   25篇
  1989年   47篇
  1988年   42篇
  1987年   47篇
  1986年   29篇
  1985年   38篇
  1984年   25篇
  1983年   25篇
  1982年   20篇
  1981年   24篇
  1980年   14篇
  1979年   13篇
  1978年   11篇
  1977年   9篇
  1976年   15篇
  1975年   12篇
  1973年   8篇
  1972年   6篇
  1971年   6篇
排序方式: 共有1852条查询结果,搜索用时 15 毫秒
101.
A 16-y-old boy who had undergone bone marrow transplantation for relapsed acute lymphoblastic leukaemia developed liver cirrhosis and refractory ascites, which did not respond to salt restriction, diuretics and abdominal paracentesis. Liver transplantation was not feasible because of poor nutritional status, pre-existing renal dysfunction and uncertainty about the prognosis of his leukaemia. The patient underwent a successful transjugular intrahepatic portosystemic shunt (TIPS), with immediate resolution of ascites, enabling cessation of diuretics and improvement in nutritional status. At 24 mo following TIPS there has been no re-accumulation of ascites. CONCLUSION: TIPS may have a role in the management of refractory ascites secondary to liver cirrhosis in selected children.  相似文献   
102.
Summary Two patients received oral penicillin for erythema migrans disease (EMD) in 1973 and 1977. Five and seven years later, respectively, they developed EMD for a second time after being bitten by ticks. The first and second erythema migrans lesions appeared in different places. Tests of sera evaluated for antibodies toBorrelia burgdorferi before (in one case), during and after the second episode of EMD remained negative (patient 1) or yielded an at least four-fold rise of IgG antibody titers, but did not become positive (patient 2). These cases provide evidence that reinfection in EMD may occur without a significant elevation of specific antibody titers.
Reinfektion bei Erythema-migrans-Krankheit
Zusammenfassung Zwei Patienten mit Erythema-migrans-Krankheit (EMK) wurden in den Jahren 1973 bzw. 1977 mit oralem Penicillin behandelt. Fünf und sieben Jahre später trat in beiden Fällen nach Zeckenstich eine EMK zum zweiten Mal auf. Die ersten und zweiten Erythema-migrans-Herde waren jeweils an verschiedenen Lokalisationen zu beobachten. Die Testungen auf Antikörper gegenüberBorrelia burgdorferi an Hand von Seren, die vor (in einem Fall), während und nach der zweiten EMK entnommen wurden, waren negativ (Patient 1) oder ergaben einen Anstieg der IgG-Titer um mindestens vier Stufen, ohne jedoch positiv zu werden (Patient 2). Diese Beobachtungen weisen darauf hin, daß eine Reinfektion bei der EMK ohne signifikant erhöhte Antikörpertiter möglich ist.
  相似文献   
103.
ObjectivesThe purpose of this research was to investigate the effects of decontamination and clinical exposure on the elastic moduli, hardness and surface roughness of two frequently used orthodontic archwires, namely 0.020 in. × 0.020 in. heat activated (martensitic active) nickel titanium archwires and 0.019 in. × 0.025 in. austenitic stainless steel archwires.MethodThis study was a prospective clinical trial in which 20 consecutive patients requiring an archwire change as part of their course of orthodontic fixed appliance therapy, had either a nickel titanium or stainless steel archwire fitted as deemed clinically necessary. The effect of clinical use was determined by comparing distal end cuts of the “as received” archwires before and after decontamination, with the same retrieved archwires following clinical use and decontamination. Hardness, elastic modulus and surface roughness were determined using an atomic force microscope (AFM) coupled with a nanoindenter.ResultsThe results showed that the decontamination regimen and clinical use had no statistically significant effect on the nickel titanium archwires, but did have a statistically significant effect on the steel archwires. Decontamination of the steel wires significantly increased the observed surface hardness (p = 0.01) and reduced the surface roughness (p = 0.02). Clinical use demonstrated a statistically significant increase in the observed elastic modulus (p < 0.001) and a decrease in surface roughness (p = 0.001).SignificanceAt present it is difficult to predict the clinical significance of these statistically significant changes in archwire properties on orthodontic tooth movement.  相似文献   
104.

Objective  

The objective of this study was to evaluate the incidence of radiographic osteoarthritis in the operated knee in comparison with the contralateral knee ten years after a bone-tendon bone patellar autograft ACL-reconstruction and to evaluate to which level patients regain activity ten years after reconstruction.  相似文献   
105.
Reiman  TH; Balfe  DM; Weyman  PJ 《Radiology》1987,163(1):49-56
In a 5-year period, 92 patients with biliary obstruction proximal to the pancreatic segment were evaluated with computed tomography (CT). Seventy-three were judged to have technically optimal studies. Observations of the level of obstruction were compared with data from 50 percutaneous transhepatic cholangiograms; CT data enabled the level of obstruction to be correctly predicted in 46. CT enabled correct prediction of the distribution of obstructing lesions in all 18 patients with intrahepatic obstruction. Forty-four of the 73 patients had pathologic examination of the porta hepatitis. CT findings of obstructing mass and lesser omental nodes resulted in correct prediction of malignancy in 25 (92%) of 27 patients; the absence of such findings enabled correct prediction of benign disease in 13 (77%) of 17 individuals. CT is most valuable as a noninvasive means of planning surgical or radiologic drainage procedures in patients with biliary obstruction.  相似文献   
106.
107.
108.
A pilot study was performed on the storage of plasma and cryosupernatant plasma at 4 degrees C for up to 28 days. Eight bags, four of CPD fresh-frozen plasma (FFP) and four of CPD cryosupernatant plasma (CSP, plasma without cryoprecipitate), were sampled during storage for assays of pH; factors V, VIII, IX, and XI; fibrinogen; prothrombin time; activated partial thromboplastin time (APTT); plasma protein electrophoresis; viscosity; and C1q binding. No changes were found in viscosity or the plasma protein electrophoretic pattern, and there was no detectable immune complex formation. The fibrinogen concentration remained constant, and the prothrombin time showed a gradual increase of 2.5 seconds for both groups of plasma. The labile coagulation factor V decreased gradually for FFP and CSP to 58 and 64 percent of its initial value, respectively (51 +/− 8% and 54 +/− 6% of the value of fresh pooled plasma). Factor VIII decreased to 36 percent of its initial value in FFP (48 +/− 14% of fresh pooled plasma). In CSP, factor VIII decreased after 28 days to 7 percent of its initial value (7 +/− 1% of fresh pooled plasma). The APTT increased for FFP from 28 to 35.8 +/− 1.1 seconds and for CSP from 36 to 49.5 +/− 4.9 seconds. The only chemical change observed for both plasmas was a rise in pH, from 7.27 to 7.56, after 28 days. The results of this pilot study indicate that FFP can be stored at 4 degrees C for 28 days with sufficient recovery of coagulation factors to maintain hemostasis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
109.
110.
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