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   2347篇
  免费   95篇
  国内免费   11篇
耳鼻咽喉   17篇
儿科学   21篇
妇产科学   26篇
基础医学   196篇
口腔科学   22篇
临床医学   152篇
内科学   511篇
皮肤病学   13篇
神经病学   135篇
特种医学   83篇
外科学   643篇
综合类   12篇
预防医学   44篇
眼科学   18篇
药学   71篇
中国医学   1篇
肿瘤学   488篇
  2023年   8篇
  2022年   13篇
  2021年   29篇
  2020年   18篇
  2019年   34篇
  2018年   42篇
  2017年   50篇
  2016年   48篇
  2015年   69篇
  2014年   104篇
  2013年   89篇
  2012年   140篇
  2011年   147篇
  2010年   82篇
  2009年   70篇
  2008年   129篇
  2007年   118篇
  2006年   92篇
  2005年   116篇
  2004年   105篇
  2003年   90篇
  2002年   85篇
  2001年   62篇
  2000年   62篇
  1999年   55篇
  1998年   17篇
  1997年   32篇
  1996年   19篇
  1995年   18篇
  1994年   24篇
  1993年   24篇
  1992年   54篇
  1991年   40篇
  1990年   45篇
  1989年   39篇
  1988年   43篇
  1987年   31篇
  1986年   42篇
  1985年   30篇
  1984年   20篇
  1983年   23篇
  1982年   10篇
  1981年   9篇
  1979年   15篇
  1978年   11篇
  1977年   10篇
  1976年   6篇
  1974年   5篇
  1970年   4篇
  1968年   6篇
排序方式: 共有2453条查询结果,搜索用时 15 毫秒
71.
72.
This bacterium is implicated in periodontal diseases of human adult type. Secretory immunoglobulin A (IgA) purified from human colostrum (HC-IgA) was incubated with Bacteroides gingivalis cells or protease isolated from the culture supernatant of B. gingivalis; the digestion of IgA was determined by immunoelectrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. B. gingivalis cells almost completely degraded HC-IgA; protease isolated from the culture supernatant cleaved both HC-IgA and secretory IgA in human parotid saliva. Thus by degradation of IgA, the protease may mediate in part the periodontopathogenic role of B. gingivalis by decreasing the oral defence mechanism.  相似文献   
73.

Purpose

Although laparoscopic liver resection has been widely adopted, performing a pure laparoscopic right hepatectomy remains a challenging procedure. The aim of this report is to evaluate the efficiency of a pure laparoscopic right hepatectomy (PLRH) in the semi-prone position using the intrahepatic Glissonian approach and a modified hanging maneuver.

Methods

Pure laparoscopic right hepatectomy was performed in the semi-prone position with the use of an intrahepatic Glissonian approach and modified hanging maneuver for patients with primary liver cancer (n = 3) and metastatic liver cancer (n = 1).

Results

The intraoperative total blood loss was only 95?C140 g (mean: 126.2 g). None of the patients required a blood transfusion, and no serious complications were encountered. The durations of the surgeries ranged from were 308 to 445 min (mean: 394.8 min). The postoperative hospital stay was 8?C11 days (mean 9.5 days).

Conclusion

Pure laparoscopic right hepatectomy in the semi-prone position using the intrahepatic Glissonian approach and a modified hanging maneuver is thus considered to be a safe modality, which minimizes intraoperative bleeding.  相似文献   
74.
The aim of this study was to clarify the role of serum S100 beta on the accurate assessment of reversibility of brain damage after fulminant hepatic failure (FHF). Among the 13 patients with FHF enrolled in this study, 12 underwent living donor liver transplantation; one patient could not the procedure because of volvulus of the sigmoid colon. Serum S100 beta was serially measured using a chemiluminescent immunoassay. Preoperative serum S100 beta in patients with diffuse brain edema was significantly higher than that in patients with localized brain edema (P < 0.05). Patients with preoperative brain death showed serum S100 beta levels over 7.0 microg/L. Serum S100 beta levels correlated with the degree of brain edema of FHF. It has the potential to be a new clinical, noninvasive indicator of brain damage due to FHF.  相似文献   
75.
76.
77.
78.
Mouse interferon induced by ultraviolet-irradiated Newcastle disease virus or polyriboinosinic-polyribocytidylic acid in T lymphocytes, B lymphocytes, macrophages, and primary mouse embryonic cell culture was studied. Irrespective of the inducer, interferons produced by T or B lymphocytes were relatively heat stable and of low antigenicity when reacted with antiserum against L-cell interferon (ALI), whereas interferons produced by macrophages and mouse embryo cells were heat labile and of high antigenicity against ALI. Mouse interferons induced by ultraviolet-irradiated Newcastle disease virus were separated into three components by chromatography on CH-Sepharose 4B. Interferons produced by T and B lymphocytes consisted primarily of component 1 (unbound fraction), whereas interferons produced by macrophages or mouse embryo cells consisted primarily of component 3 (eluted by 0.5 M NaCl). Component 1 was heat stable and of low antigenicity against ALI, properties characteristic of T- and B-cell interferon. Components 2 and 3 were heat labile and of high antigenicity against ALI, properties characteristic of macrophage and mouse embryo cell interferon. In contrast, interferon induced in mice sensitized with BCG differed from these interferons induced in B cells, T cells, macrophages, and fibroblasts in being extremely acid labile and nonreactive against ALI.  相似文献   
79.
Previous behavioral studies have indicated that the nucleus accumbens (NAc) shell of a male rat is involved in its sexual behavior; however, no previous studies have investigated neuronal activities in the male rat NAc shell during sexual behavior. To investigate this issue, we recorded single unit activities in the NAc shell of male rats during sexual behavior. Of 123 NAc shell neurons studied, 53, 47, and 40 neurons exhibited significantly changed firing rates at various times during intromission, genital auto-grooming, and sniffing of females, respectively. The two types of NAc shell neurons [putative fast spiking interneurons (pFSIs) and medium spiny neurons (pMSNs)] responded differently during sexual behavior. First, more pFSIs than pMSNs exhibited inhibitory responses to thrusting with intromission and genital grooming, while pFSIs and pMSNs responded similarly to sniffing of females. Second, both pFSIs and pMSNs responded differently to thrusting with and without intromission. Furthermore, NAc shell neuronal activity was significantly different across the different phases of sexual behavior, and the number of NAc shell neurons with delta oscillation, which is related to behavioral inhibition, and high gamma oscillation, which is related to reward perception, increased after ejaculation. Together, our results suggest that the NAc shell is deeply involved in sexual behavior, and changes in NAc shell neuronal activity are related to performance of sexual behavior, encoding cues or contexts related to sexual behavior, reward-related processing, and the inhibition of sexual behavior after ejaculation.  相似文献   
80.
We investigated the presence of human herpesvirus 6 (HHV-6) and herpes simplex virus (HSV) in surgical tissue from temporal lobe epileptic patients. A total of 17 cases were studied, including eight males and nine females. The mean age was 24.9 +/- 11.1 years and the mean age of onset was 11.1 +/- 5.4 years. Five patients were diagnosed as encephalitis/meningitis and another three had a history of suspected encephalitis/meningitis, but no patient showed any obvious neurological symptom or mental handicap. Mesial and lateral temporal tissues were examined by polymerase chain reaction. Among six patients positive for HHV-6 (35%), the mesial temporal lobe was positive in four and the lateral temporal lobe was positive in three. Herpes simplex virus was positive in only one patient. Three of the six patients positive for HHV-6 did not show any apparent causes. Mild encephalitis/meningitis induced by HHV-6, a condition sometimes not recognized as encephalitis/meningitis, may be one of the most frequent causes of temporal lobe epilepsy.  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