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   6449篇
  免费   438篇
  国内免费   21篇
耳鼻咽喉   42篇
儿科学   138篇
妇产科学   97篇
基础医学   1155篇
口腔科学   103篇
临床医学   645篇
内科学   1321篇
皮肤病学   203篇
神经病学   796篇
特种医学   276篇
外科学   607篇
综合类   44篇
一般理论   3篇
预防医学   452篇
眼科学   94篇
药学   454篇
中国医学   8篇
肿瘤学   470篇
  2023年   34篇
  2022年   74篇
  2021年   143篇
  2020年   83篇
  2019年   117篇
  2018年   125篇
  2017年   98篇
  2016年   135篇
  2015年   215篇
  2014年   224篇
  2013年   253篇
  2012年   435篇
  2011年   493篇
  2010年   279篇
  2009年   272篇
  2008年   462篇
  2007年   484篇
  2006年   400篇
  2005年   433篇
  2004年   368篇
  2003年   359篇
  2002年   333篇
  2001年   87篇
  2000年   64篇
  1999年   88篇
  1998年   86篇
  1997年   77篇
  1996年   57篇
  1995年   53篇
  1994年   55篇
  1993年   39篇
  1992年   40篇
  1991年   35篇
  1990年   27篇
  1989年   24篇
  1988年   21篇
  1987年   29篇
  1986年   34篇
  1985年   31篇
  1984年   29篇
  1983年   22篇
  1982年   12篇
  1981年   13篇
  1980年   14篇
  1978年   12篇
  1974年   13篇
  1973年   10篇
  1972年   11篇
  1971年   12篇
  1970年   9篇
排序方式: 共有6908条查询结果,搜索用时 15 毫秒
1.
Background The objective was to measure the plasma concentrations of thymulin and nerve growth factor (NGF) in a group of patients with primary open angle glaucoma (POAG) and compare them with age- and sex-matched normal controls.Methods Twenty-eight patients newly diagnosed with POAG who were not undergoing treatment were compared with the same number of age- and sex-matched healthy controls. Blood samples were drawn into heparinized tubes and plasma samples were collected for the determination of the concentrations of thymulin and NGF, using specific enzyme-linked immunosorbent assay (ELISA). The Student’s t test was used to perform the necessary statistical analysis of the results.Results Seventeen women and 11 men were enrolled in each of the two groups (study and control), with a mean age of 63.7 (SD 10.3) years in the former and 63.3 (SD 9.6) years in the latter. There was a highly significant (p<0.001) elevation in the thymulin levels in POAG patients compared with the control group. However, no significant difference was observed when comparing the plasma NGF levels.Conclusion This is the first report to measure plasma thymulin levels in glaucoma patients. The significant results point the possible role of this immunomodulator in the pathogenesis of primary open angle glaucoma. The potential role of NGF seems to be less likely. These findings warrant further investigation.  相似文献   
2.
3.
Background: Recent reports indicate increased incidence of Clostridium botulinum infections, particularly among drug abusers and tissue allograft recipients. Botulinum toxin also has potential application in biochemical warfare. The neurotoxin-induced paralysis often requires mechanical ventilation with and without muscle relaxants. The authors investigated the long-term effects of botulinum toxin on muscle function, expression of nicotinic acetylcholine receptors (nAChRs), and their interaction with muscle relaxant, atracurium.

Methods: Rats (n = 30) were injected with varying doses (0.625, 2.5, and 10 U) of botulinum toxin into the tibialis muscle. Control animals (n = 9) received an equivalent volume of saline. At 128 days after injection, neuromuscular function, pharmacodynamics of atracurium, and nAChRs were evaluated.

Results: Nerve-evoked tensions, including tetanic tension and muscle mass, were decreased on the toxin-injected side in a dose-dependent manner relative to saline-injected controls as well as the contralateral side. Specific muscle tension and specific tetanic muscle tension (tensions/muscle mass) were not reduced. The ED10 of atracurium was reduced, the ED50 was unchanged, and the ED90 was increased in the highest (10-U) dose of toxin group. The atracurium plasma concentration to maintain a steady state 50% paralysis was significantly reduced in the 10-U toxin group. The nAChR concentrations in the tibialis muscle were significantly increased in a dose-dependent manner in all experimental groups.  相似文献   

4.
5.
Twenty-four patients treated with 150 mg amitriptyline per day for an episode of major depression underwent a standardized heart rate analysis (HRA) before therapy and after 14 days. The battery of cardiovascular reflex tests included the determination of the coefficient of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the heart rate response to standing, and the Valsalva manoeuvre. The results of the initial HRA did not differ from a group of 24 normal control subjects matched for age and sex. On day 14 of treatment the patients showed significantly reduced values of heart rate variability in all tests (P<0.0001), probably due to the anticholinergic side effects of amitriptyline. Heart rate increased form 78.1 to 93.6 bpm on average (P<0.0001). Abnormal CV at rest was registered in 96% of the patients; during deep respiration 29% showed abnormal CV results. An abnormal spectral analysis was found in 100% of the cases (low frequency peak: 42%, mid-frequency peak: 100%, high frequency peak: 79%). The heart rate response to standing was abnormal in 75% and the Valsalva test in 33% of the cases. Eighty-eight percent of the patients fulfilled the criteria of a cardiovascular autonomic neuropathy under the conditions of amitriptyline therapy. As yet, the consequences of these changes for the patients have not been sufficiently elucidated.  相似文献   
6.
7.
8.
In cystic fibrosis (CF), absorption of tacrolimus through the gastrointestinal tract may be impaired due to fat malabsorption. The aim of this pilot study was to compare tacrolimus pharmacokinetics and inter- and intrasubject variability of exposure in stable lung transplant recipients with and without CF, and to determine the best single-time predictors of exposure. The study included 11 lung transplant recipients with CF and 11 without CF who received tacrolimus twice daily. Blood samples were obtained predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8 and 12 h postdose on 3 separate days within 1 week. Tacrolimus pharmacokinetics and inter- and intrasubject variability of exposure were similar in the two groups, though exposure-per-milligram-dose was approximately 50% lower in CF patients. Tacrolimus trough concentration did not accurately predict the area under the concentration curve (AUC(0-12)), but the concentration measured 3 h postdose (C(3)) was tightly correlated with the AUC(0-12) in both CF (r(2)= 0.86) and non-CF (r(2)= 0.92) patients. In summary, patients with CF have a higher tacrolimus oral clearance, but nonsignificant differences in short-term inter- and intrasubject variability of exposure compared to patients without CF. C(3) is tightly correlated with AUC(0-12) in lung transplant recipients with and without CF.  相似文献   
9.
We reviewed the treatment outcome of 69 patients with Ewing's sarcoma of the femur. The patients received chemotherapy according to the CESS 81 (n 14), CESS 86 (n 43), and CESS 91P (n 12) protocols. The 10-year relapse-free survival rates were 36%, 65%, and 65% (p = 0.01). 68 patients received local treatment. The primary tumor was treated by surgery without radiotherapy in 28 patients; 1 developed a local recurrence and 7 metastases. 10 patients received radiotherapy alone; 4 developed metastases and 4 local recurrences and metastases. 30 cases had a combination of surgery and radiotherapy; 7 developed metastases and 1 a local recurrence and metastasis. The survival of patients after radiotherapy alone was worse than that of patients after surgery with/without radiotherapy (p = 0.005). Pathological fractures (n 16) did not influence the prognosis.  相似文献   
10.
Methicillin-resistant Staphylococcus aureus (MRSA) has traditionally been a nosocomial pathogen. However, several recent studies have noted community-acquired MRSA among young, healthy patients with no risk factors or healthcare system exposure. We report the transmission of a strain of community-acquired MRSA in our neonatal intensive care unit.  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