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   4626篇
  免费   218篇
  国内免费   82篇
耳鼻咽喉   78篇
儿科学   77篇
妇产科学   92篇
基础医学   753篇
口腔科学   77篇
临床医学   440篇
内科学   1086篇
皮肤病学   84篇
神经病学   252篇
特种医学   440篇
外科学   456篇
综合类   45篇
一般理论   4篇
预防医学   181篇
眼科学   26篇
药学   467篇
中国医学   66篇
肿瘤学   302篇
  2023年   22篇
  2022年   21篇
  2021年   142篇
  2020年   72篇
  2019年   85篇
  2018年   114篇
  2017年   72篇
  2016年   117篇
  2015年   192篇
  2014年   206篇
  2013年   251篇
  2012年   373篇
  2011年   342篇
  2010年   230篇
  2009年   197篇
  2008年   252篇
  2007年   300篇
  2006年   230篇
  2005年   225篇
  2004年   153篇
  2003年   139篇
  2002年   98篇
  2001年   106篇
  2000年   74篇
  1999年   80篇
  1998年   78篇
  1997年   50篇
  1996年   84篇
  1995年   59篇
  1994年   50篇
  1993年   58篇
  1992年   29篇
  1991年   21篇
  1990年   25篇
  1989年   34篇
  1988年   38篇
  1987年   39篇
  1986年   34篇
  1985年   38篇
  1984年   26篇
  1983年   12篇
  1982年   13篇
  1981年   25篇
  1980年   22篇
  1979年   9篇
  1978年   17篇
  1977年   17篇
  1976年   9篇
  1975年   11篇
  1971年   6篇
排序方式: 共有4926条查询结果,搜索用时 468 毫秒
1.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
2.
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients.  相似文献   
3.
Camellia sinensis polysaccharide has been reported to possess anti‐adhesive activity against pathogens. The present study was designed to investigate whether hot water extracts obtained from green tea leaves might inhibit pathogen adhesion to human or mouse cell lines. Green tea extract‐4 (CSI‐4) with the maximum yield of 4% (w/v) is composed of a major proportion of carbohydrates containing 40% uronic acids, but lack of catechins. It showed strong inhibitory activities against hemagglutination mediated by pathogens Helicobacter pylori, Propionibacterium acnes and Staphylococcus aureus with the minimum inhibitory concentrations of 0.01‐0.5 mg/mL. CSI‐4 further demonstrated an inhibitory effect on the adhesion of these pathogens to host cell lines with the IC50 values (50% inhibition of adhesion) of 0.14–2.3 mg/mL. It exhibited the highest activity against P. acnes, but no inhibitory effects were observed against Lactobacillus acidophilus, Bifidobacterium bifidum, Escherichia coli, or Staphylococcus epidermidis. Our results suggest that CSI‐4 may exert a selective anti‐adhesive effect against certain pathogenic bacteria with no adverse effects against beneficial or commensal bacteria. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
4.
5.
Object A radiation dose of 40–50 Gy is able to produce a cure rate of more than 90% in intracranial pure germinoma. However, many attempts have been made to reduce the dose and volume of radiation without compromising the disease control rate because of the toxicity of irradiation. This retrospective study is intended to provide the physician with an appropriate therapeutic strategy. Materials and methods We reviewed a series of 10 recurrent germinomas among 117 germinomas diagnosed histologically or clinically between 1979 and 2002. These patients involved underwent three different treatment modalities; radiation alone (N = 71), chemotherapy alone (N = 9), and combined therapy (N = 37). The 10-year overall and relapse-free survival rates were 97 and 93% in the radiation alone group, 89 and 67% in the chemotherapy alone group, and 92 and 92% in the combined therapy group, respectively. As expected, both radiation therapy and combined therapy were effective in controlling the disease. Tumor recurrence was closely related to the volume of radiation but not to the dose of radiation. If the tumor bed and craniospinal axis were fully covered, the radiation dose might be reduced. Chemotherapy alone showed earlier recurrence and a higher tumor recurrence rate. In the case of combined therapy, chemotherapy was useful in reducing the radiation dose but revealed some toxicity (death of two patients). Conclusions The investigation of a possible further dose reduction seems worthwhile. Radiation therapy alone with a dose of less than 40 Gy should be compared with ongoing chemotherapeutic protocols combined with low-dose irradiation.  相似文献   
6.
7.
8.
9.
Endobronchial tuberculosis is present in 10-40% of patients with active pulmonary tuberculosis, and more than 90% of the patients with endobronchial tuberculosis have some degree of bronchial stenosis. The primary treatment for tuberculous bronchial stenosis is antituberculous chemotherapy combined with steroids, but some patients do not respond well, and more aggressive treatment is needed to restore the patency of the involved bronchus. Balloon dilatation of tuberculous bronchial stenosis has been reported to be successful. However, in our experience, balloon dilatation of the stenotic segment has not significantly improved patients' clinical symptoms except in those with very short segmental stenosis. We describe a case of tuberculous bronchial stenosis that was successfully treated with Gianturco self-expanding metallic stents.  相似文献   
10.
Interactions between mivacurium and pancuronium   总被引:1,自引:0,他引:1  
We have compared the dose-response relationships of mivacurium, pancuronium and their combination, and examined the interactions by isobolographic and fractional analyses. We studied 70 adult patients during nitrous oxide-fentanyl-propofol anaesthesia. The dose-response curves were determined by probit analysis. The ED95 and ED50 values for mivacurium were 84.2 (95% confidence interval 80.2-88.1) micrograms kg- 1 and 46.2 (40.2-52.1) micrograms kg-1, respectively. Corresponding values for pancuronium were 68.5 (63.7-73.2) micrograms kg-1 and 40.7 (35.5-45.9) micrograms kg-1, respectively. Isobolographic and fractional analyses of the mivacurium-pancuronium combination demonstrated a synergistic interaction. An additional 30 patients were allocated randomly to receive either mivacurium 84.2 micrograms kg-1 (n = 15) or pancuronium 68.5 micrograms kg-1 (n = 15). When the first twitch (T1) of TOF recovered to 25%, each patient received mivacurium 46.2 micrograms kg-1. The times after administration of mivacurium until T1 25% in the mivacurium-pancuronium group were 6.4 (3.5-9.4) min and 49.8 (44.7-54.9) min, respectively (P < 0.0001). We conclude that the combination of mivacurium and pancuronium was synergistic and after pancuronium-induced neuromuscular block, mivacurium became a longer acting agent than the shorter agent.   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