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   4184篇
  免费   195篇
  国内免费   110篇
耳鼻咽喉   80篇
儿科学   48篇
妇产科学   89篇
基础医学   745篇
口腔科学   68篇
临床医学   386篇
内科学   941篇
皮肤病学   74篇
神经病学   245篇
特种医学   235篇
外科学   451篇
综合类   42篇
一般理论   4篇
预防医学   167篇
眼科学   30篇
药学   517篇
中国医学   65篇
肿瘤学   302篇
  2023年   22篇
  2022年   83篇
  2021年   139篇
  2020年   75篇
  2019年   89篇
  2018年   107篇
  2017年   75篇
  2016年   123篇
  2015年   183篇
  2014年   203篇
  2013年   245篇
  2012年   369篇
  2011年   338篇
  2010年   219篇
  2009年   189篇
  2008年   250篇
  2007年   319篇
  2006年   229篇
  2005年   228篇
  2004年   144篇
  2003年   132篇
  2002年   98篇
  2001年   105篇
  2000年   71篇
  1999年   72篇
  1998年   51篇
  1997年   31篇
  1996年   44篇
  1995年   27篇
  1994年   23篇
  1993年   18篇
  1992年   28篇
  1991年   18篇
  1990年   14篇
  1989年   15篇
  1988年   11篇
  1987年   5篇
  1986年   10篇
  1985年   11篇
  1984年   13篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
  1978年   9篇
  1976年   3篇
  1973年   4篇
  1972年   4篇
  1971年   6篇
  1970年   4篇
  1968年   5篇
排序方式: 共有4489条查询结果,搜索用时 15 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.
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   
4.
5.
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   
6.
1. Fifty-five intact and six baroreceptor denervated and vagotomized cats of either sex were anaesthetized intraperito-neally with urethane (400 mg/kg) and a-chloralose (40 mg/kg). Responses of the systemic arterial pressure (SAP), mean SAP (MSAP) and sympathetic vertebral nerve (VNA) and renal nerve activities (RNA) were recorded. 2. In intact animals, monosodium L-glutamate (Glu, 0.1 mol/L, 50 nL) was microinjected into pressor areas of the locus coeruleus (LC), gigantocellular tegmental field (GTF), rostral ventrolateral medulla (RVLM) and dorsomedial medulla (DM), and the depressor areas of caudal ventrolateral medulla (CVLM). The induced actions were compared before and after microinjection of either glutamate antagonists, glutamate diethylester (GDEE, 0.5 mol/L, 50–100nL), a competitive AMPA receptor blocker, or 2-amino-5-phosphonovaleric acid (D-AP5, 0.025 mol/L, 50–100 nL), a competitive N-methyl-D-aspartate (NMDA) receptor blocker. GDEE completely blocked the increases of SAP and VNA elicited from all pressor areas. D-AP5 only partially blocked the pressor but slightly blocked VNA and RNA responses from LC, GTF and DM, particularly those from RVLM. Neither GDEE nor D-AP5 blocked the depressor responses of SAP and two nerve activities elicited from CVLM. 3. In baroreceptor denervated animals, NMDA (2 mmol/L, 50–100 nL) and AMPA (0.2 mmol/L, 50–100 nL) were micro-injected into the same pressor areas of GTF, RVLM and DM and the depressor area of CVLM responsive to Glu activation (0.1 mol/L, 30 nL). In RVLM, DM and CVLM, the results of either NMDA or AMPA were similar to those induced by Glu. However, in GTF, microinjection of either NMDA or AMPA did not induce similar responses to Glu. This suggests that the nature of GTF may differ from RVLM and DM. 4. The above results suggest that the Glu-induced pressor responses from LC, GTF, DM and especially RVLM, are primarily mediated through AMPA receptors. The Glu-induced depressor responses from CVLM may not be predominantly mediated by either AMPA or NMDA receptors. 5. In both baroreceptor-intact and -denervated cats stimulation of the pressor areas often produced an increase of VNA and a decrease of RNA, while in the depressor CVLM decreased both VNA and RNA. The VNA, but not RNA were positively correlated with the pressor responses, while both VNA and RNA were positively correlated with the depressor responses. This may suggest that neurons of the sympathetic vertebral and renal nerves are topographically organized in the brain.  相似文献   
7.
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   
8.
Objects We designed several distraction devices and applied these instruments in 14 patients with varying types of craniosynostosis. The aim of this report is to clarify the advantages and disadvantages of these surgical methods and to discuss current concepts for the surgical strategy in the treatment of craniosynostosis. Methods From January 2000 to July 2005, 28 patients with craniosynostosis were retrospectively analyzed. Surgical treatment was performed on 14 patients using the distraction method with internal distraction devices that we designed, in which 5 patients had plagiocephaly, 3 brachycephaly, and 6 scaphocephaly. All patients underwent preoperative and postoperative evaluations, which included the patient’s neurological state, and three-dimensional CT. Results With distraction devices, the time required for the surgery could be shortened almost 3 1/3 h; the bleeding during the surgery was decreased with reduced requirement of more than 200 ml of blood transfusion as compared with remodeling surgery. Postoperatively achieved distraction distances varied from 30.0 to 47.5 mm (mean, 42.99 mm). The average increased volume percent of cranium in distraction surgery group was 20.9% (range, −11.5 to 58.9%) after full distraction. Conclusion With distraction surgery, satisfactory cranial volume expansion and aesthetically pleasing morphological states were achieved in all cases, and the efficacy was statistically significantly high as compared with remodeling method.  相似文献   
9.
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs.  相似文献   
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