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   2058篇
  免费   151篇
  国内免费   6篇
耳鼻咽喉   10篇
儿科学   40篇
妇产科学   36篇
基础医学   275篇
口腔科学   121篇
临床医学   249篇
内科学   361篇
皮肤病学   24篇
神经病学   248篇
特种医学   51篇
外科学   306篇
综合类   26篇
一般理论   3篇
预防医学   140篇
眼科学   52篇
药学   173篇
中国医学   25篇
肿瘤学   75篇
  2024年   2篇
  2023年   29篇
  2022年   58篇
  2021年   97篇
  2020年   78篇
  2019年   111篇
  2018年   109篇
  2017年   90篇
  2016年   75篇
  2015年   74篇
  2014年   85篇
  2013年   129篇
  2012年   164篇
  2011年   172篇
  2010年   105篇
  2009年   88篇
  2008年   121篇
  2007年   103篇
  2006年   82篇
  2005年   72篇
  2004年   58篇
  2003年   69篇
  2002年   38篇
  2001年   19篇
  2000年   15篇
  1999年   13篇
  1998年   4篇
  1997年   16篇
  1996年   8篇
  1995年   12篇
  1994年   15篇
  1993年   9篇
  1992年   8篇
  1991年   9篇
  1990年   9篇
  1989年   11篇
  1988年   10篇
  1987年   10篇
  1986年   4篇
  1985年   11篇
  1984年   5篇
  1982年   3篇
  1981年   5篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   3篇
  1975年   1篇
  1972年   1篇
排序方式: 共有2215条查询结果,搜索用时 15 毫秒
71.
72.
Journal of NeuroVirology - Multiple sclerosis (MS) is one of the common autoimmune diseases. The exact etiology of MS is still unclear, but recent studies have shown the possibility of infectious...  相似文献   
73.
Neurological Sciences - Spinal muscular atrophy (SMA), an autosomal recessive neurodegenerative disorder of alpha motor neurons of spinal cord associated with progressive muscle weakness and...  相似文献   
74.
Wiener Medizinische Wochenschrift - Infection prevention protocols are the accepted standard to control nosocomial infections. These protective measures intensified after the coronavirus 2019...  相似文献   
75.

Purpose

Sciatic nerve block (SNB) is commonly performed in combination with femoral nerve block (FNB) for postoperative analgesia following total knee arthroplasty (TKA). Despite the fact that 10–20 % of TKA patients require SNB for postoperative posterior knee pain, there are no existing studies that suggest a model to predict the need for SNB. The aim of our study was to develop a prediction tool to measure the likelihood of patients undergoing TKA surgery requiring a postoperative SNB.

Methods

With institutional review board approval, we obtained data from the electronic medical record of patients who underwent TKA at the Cleveland Clinic. A multivariable logistic regression was used to estimate the probability of requiring a postoperative SNB. Clinicians selected potential predictors to create a model, and the potential nonlinear association between continuous predictors and SNB was assessed using the restricted cubic spline model.

Results

In total 6279 TKA cases involving 2329 patients with complete datasets were used for building the prediction model, including 276 (12 %) patients who received a postoperative SNB and 2053 (88 %) patients who did not. The estimated C statistic of the prediction model was 0.64. The nomogram is used by first locating the patient position on each predictor variable scale, which has corresponding prognostic points. The cut-off of 11.6 % jointly maximizes the sensitivity and specificity.

Conclusion

This is the first study to be published on SNB prediction after TKA. Our nomogram may prove to be a useful tool for guiding physicians in terms of their decisions regarding SNB.
  相似文献   
76.
77.
BACKGROUND: Traditional doses of depot GnRH agonist may be excessive for ovarian stimulation. We compared half-dose depot triptorelin (Group I) with reduced-dose daily buserelin (Group II) in a long protocol ICSI/embryo transfer through a double-blind randomized clinical trial. METHODS: Controlled ovarian stimulation (COS) was started by a pretreatment with oral contraceptives for 21 days. Then, 182 patients were randomized into two groups of 91. Group I received 1.87 mg triptorelin depot i.m. followed by daily s.c. injections of saline. Group II (reduced-dose protocol) received a bolus injection of i.m. saline followed by daily s.c. injections of 0.5 mg buserelin, which was then reduced to 0.25 mg at the start of human menopausal gonadotrophin stimulation. When transvaginal ultrasound showed at least two follicles of 16-20 mm diameter, HCG was given and ICSI was performed 40-42 h later. RESULTS: No significant differences were seen in the mean (SD) number of follicles at HCG administration, as our primary outcome [10.3 (4.4) in Group I versus 11.1 (4.2) in Group II, P = 0.180, mean difference = 0.86, 95% confidence interval 0.39-2.11]. The other early results of COS, clinical and ongoing pregnancy rates, or early pregnancy loss were also not significantly different between the groups. Group I endured longer stimulation period [11.2 (1.8) days versus 10.6 (1.9), P = 0.030]. CONCLUSIONS: Clinical outcomes were not significantly different between Group I and Group II.  相似文献   
78.
14‐(R,S)‐[18F]fluoro‐6‐thia‐heptadecanoic acid is a tracer for fatty acid imaging by positron emission tomography. High demand for this tracer required us to replace semiautomatic synthesis with a fully automated procedure. An automated synthesis device was constructed in‐house for multistep nucleophilic 18F‐fluorination and a control system was developed. The synthesis device was combined with a sterile filtration unit and both were qualified. 14‐(R,S)‐[18F]fluoro‐6‐thia‐heptadecanoic acid was produced according to good manufacturing practice guidelines set by the European Union. The synthesis includes an initial nucleophilic labelling reaction, deprotection, preparative HPLC separation, purification of the final product, and formulation for injection. The duration and temperature of the reaction and hydrolysis were optimized, and the radiochemical stability of the formulated product was determined. The rotary evaporator used to evaporate the solvent after HPLC purification was replaced with solid phase extraction purification. We also replaced the human serum albumin used in the earlier procedure with a phosphate buffer‐ascorbic acid mixture in the final formulation solution. From 2011 to 2016, we performed 219 synthesis procedures, 94% of which were successful. The radiochemical yield of 14‐(R,S)‐[18F]fluoro‐6‐thia‐heptadecanoic acid, decay‐corrected to the end of bombardment, was 13% ± 6.3%. The total amount of formulated end product was 1.7 ± 0.8 GBq at end of synthesis.  相似文献   
79.
80.
In the present study, we fabricated an efficient, simple biomimetic scaffold to stimulate osteogenic differentiation of mesenchymal stem cells (MSCs). Electrospun poly L-lactic acid nanofibers were employed to mimic the nanofibrillar structure of bone proteins and coated with hydroxyapatite nanoparticles to simulate bone minerals. Thereafter, we regulated the release pattern of BMP-2 peptide through covalent attachment of an optimized liposomal formulation to the scaffold. The fabricated platform provided a sustained release profile of BMP-2 peptide up to 21?days while supporting cellular attachment and proliferation without cytotoxicity. In-vitro results confirmed the superiority of the scaffold containing liposomes through enhancement of growth and differentiation of MSCs. Ectopic bone formation model exhibited significant localized initiation of bone formation of liposome incorporated scaffold. Consequently, these findings demonstrated that our designed platform with modified release properties of BMP-2 peptide considerably promoted osteogenic differentiation of MSCs making it a unique candidate for bone regeneration therapeutics.  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