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   9802篇
  免费   706篇
  国内免费   36篇
耳鼻咽喉   72篇
儿科学   295篇
妇产科学   203篇
基础医学   1394篇
口腔科学   336篇
临床医学   833篇
内科学   2433篇
皮肤病学   263篇
神经病学   786篇
特种医学   314篇
外国民族医学   4篇
外科学   1434篇
综合类   50篇
一般理论   2篇
预防医学   883篇
眼科学   176篇
药学   548篇
中国医学   65篇
肿瘤学   453篇
  2023年   76篇
  2022年   182篇
  2021年   376篇
  2020年   195篇
  2019年   293篇
  2018年   385篇
  2017年   250篇
  2016年   253篇
  2015年   244篇
  2014年   341篇
  2013年   475篇
  2012年   595篇
  2011年   683篇
  2010年   393篇
  2009年   324篇
  2008年   494篇
  2007年   530篇
  2006年   558篇
  2005年   442篇
  2004年   421篇
  2003年   404篇
  2002年   367篇
  2001年   255篇
  2000年   296篇
  1999年   246篇
  1998年   79篇
  1997年   51篇
  1996年   53篇
  1995年   50篇
  1994年   42篇
  1993年   41篇
  1992年   129篇
  1991年   134篇
  1990年   118篇
  1989年   74篇
  1988年   71篇
  1987年   57篇
  1986年   67篇
  1985年   70篇
  1984年   47篇
  1983年   37篇
  1982年   25篇
  1979年   19篇
  1978年   23篇
  1973年   23篇
  1972年   23篇
  1971年   23篇
  1970年   27篇
  1968年   18篇
  1967年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
Background  Surgical procedures enhance production of pro- and anti-inflammatory cytokines and angiogenic factors that play a pivotal role in the immunological response to surgical trauma and take part in the pathogenesis of tumor growth and adhesions formation. The purpose of the study was to access the influence of low-pressure CO2 pneumoperitoneum on the inflammatory and angiogenic responses during the postoperative period after laparoscopy. Methods  The study group consisted of 40 patients, operated on due to cholelithiasis using standard-pressure (n = 20) and low-pressure (n = 20) CO2 pneumoperitoneum. Serum concentration of interleukin (IL)-6, IL-8, IL-10, vascular endothelial growth factor (VEGF)-A, and endostatin were measured before and at 6, 24, and 48 h after surgery with commercially available enzyme-linked immunosorbent assay (ELISA). Results  Concentrations of IL-6 increased significantly after the operations in both groups. No differences were observed between the groups in regards to IL-6, IL-8, and IL-10 levels. Concentrations of VEGF-A measured at 6 and 48 h were significantly lower in patients who underwent laparoscopies performed with low-pressure pneumoperitoneum. No significant variations were observed in endostatin serum concentration. Concentrations of the studied parameters were not influenced by duration of surgery or by age, gender, or body mass index (BMI) of the patients. Conclusions  The results obtained in our study do not show any significant differences between studied operative procedures with regards to systemic inflammatory response. Changes in the concentrations of VEGF-A and endostatin observed in the studied population may suggest this technique is more favorable with regards to angiogenesis process intensity, along with all its consequences and implications.  相似文献   
4.
5.
6.
In living donor liver transplantation (LDLT), obtaining the precise volume of the graft is very important to decrease volume-related postoperative complications, especially in cases with suspected small-for size grafts. We used stereology based on the Cavalieri method (CM), a new method to measure liver graft volume, and compared the results with those obtained through intraoperative measurement (IOM) and through multidetector computed tomography (MDCT) measurement. Liver volumes estimated using the 3 methods were well-correlated with each other (r(2) = 0.94 and P < 0.001 for IOM and CM; r(2) = 0.91 and P < 0.001 for IOM and MDCT, and r(2) = 0.95 and P < 0.001 for CM and MDCT); however, they were different from each other (in descending order, 908 +/- 124 cm(2), 861 +/- 121 cm(2), and 777 +/- 168 cm(2) for MDCT, CM, and IOM, respectively). Although MDCT and CM overestimated the volumes, the results of CM were almost similar to those obtained via IOM. In conclusion, our results suggest that CM measured the liver graft volume more reliably. Thus, its use, particularly in cases with suspected small-for-size graft, may prove useful.  相似文献   
7.
The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160-600 m). It declined by 19% (16 m.yr(-1)) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30-50% predicted) and by 26% (15 m.yr(-1)) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases.  相似文献   
8.
We describe a novel human zinc finger cNDA, C2H2-171. This cDNA represents an mRNA which encodes a protein of 484 amino acids and a calculated molecular weight of 54 kD. Four zinc finger-like domains are found in the C-terminal end of the protein. At the N-terminus, C2H2-171 contains a POZ/tramtrack-like domain similar to that found in the tumor associated zinc finger proteins LAZ-3/BCL-6 and PLZ-F, as well as in non-zinc finger proteins. C2H2-171 RNA is preferentially expressed in the brain, and increases during the course of murine development, with maximal expression in the adult. C2H2-171 RNA is differentially expressed in brain regions, with the highest level of expression in the cerebellum. C2H2-171 RNA was expressed at high levels in primary cerebellar granule cell neurons compared to astrocytes. The gene encoding C2H2-171 is highly conserved in vertebrates, and maps to the terminus of human chromosome 1 (1q44-ter). This chromosomal location is associated with a number of cytogenetic aberrations including those involving brain developmental anomalies and tumorigenesis. These data suggest that C2H2-171 may play an important role in vertebrate brain development and function.  相似文献   
9.
10.
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