全文获取类型
收费全文 | 1756篇 |
免费 | 139篇 |
国内免费 | 63篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 71篇 |
妇产科学 | 58篇 |
基础医学 | 261篇 |
口腔科学 | 32篇 |
临床医学 | 198篇 |
内科学 | 304篇 |
皮肤病学 | 34篇 |
神经病学 | 106篇 |
特种医学 | 267篇 |
外科学 | 118篇 |
综合类 | 63篇 |
预防医学 | 124篇 |
眼科学 | 15篇 |
药学 | 224篇 |
肿瘤学 | 67篇 |
出版年
2021年 | 29篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 24篇 |
2017年 | 21篇 |
2016年 | 19篇 |
2015年 | 32篇 |
2014年 | 33篇 |
2013年 | 47篇 |
2012年 | 56篇 |
2011年 | 59篇 |
2010年 | 51篇 |
2009年 | 60篇 |
2008年 | 48篇 |
2007年 | 88篇 |
2006年 | 53篇 |
2005年 | 70篇 |
2004年 | 56篇 |
2003年 | 48篇 |
2002年 | 43篇 |
2001年 | 57篇 |
2000年 | 42篇 |
1999年 | 43篇 |
1998年 | 67篇 |
1997年 | 67篇 |
1996年 | 66篇 |
1995年 | 64篇 |
1994年 | 38篇 |
1993年 | 50篇 |
1992年 | 26篇 |
1991年 | 33篇 |
1990年 | 31篇 |
1989年 | 67篇 |
1988年 | 46篇 |
1987年 | 45篇 |
1986年 | 27篇 |
1985年 | 36篇 |
1984年 | 33篇 |
1983年 | 20篇 |
1982年 | 26篇 |
1981年 | 20篇 |
1980年 | 23篇 |
1979年 | 19篇 |
1978年 | 14篇 |
1977年 | 19篇 |
1976年 | 16篇 |
1975年 | 13篇 |
1973年 | 14篇 |
1968年 | 7篇 |
1967年 | 9篇 |
排序方式: 共有1958条查询结果,搜索用时 62 毫秒
11.
LEE JS IM HH JUNG Y JUNG IS JANG JY CHUN YK CHO YD KIM JO CHO JY KIM YS SHIM CS & KIM BS 《Neurogastroenterology and motility》2006,18(6):493-494
Background: Recent development of extracorporeal magnetic stimulation (ECMS) which uses current‐changing magnetic fields allows the induction of electrical stimulation in the desired deep tissue. Recent study showed the sacral nerve stimulation reduces corticoanal excitability that may play a functional role in anal continence mechanisms. Preliminary study shows that ECMS of sacral nerve can modify pelvic floor function and expel rectal balloon in patients with pelvic floor dyssynergia (PFD). Aims: To evaluate the effect of ECMS compared with biofeedback therapy (BF) in patients with PFD. Methods and Materials: Thirty‐eight patients who fulfilled Rome II criteria for PFD by colon transit time and anorectal function tests, were randomly treated with 8 sessions of ECMS (2/weeks; n = 19) at prone position or BF (2/weeks; n = 19) at sitting position. Stimulation parameters were set at 50–80% of maximum intensity, 10 and 50 Hz frequency, 3 s burst length with 3 and 6 s off using arm‐typed stimulator (BioCom‐1000, Mcube Co., Korea). Symptom scores for constipation with/without anorectal function test were repeatedly measured after each treatment. Response was defined as 50% or more decreased symptom score after treatment (partial response: 30–50%, poor: <30%). Results: Fifteen patients (age 49.1 ± 13.4 years, mean ± SD; 4 men) completed 8 session of BF and 14 patients (54.5 ± 17.6 years, 3 men) completed 8 session of ECMS. Four patients of BF group discontinued treatment due to unsatisfactory therapeutic effect (n = 1) and withdrew consent (n = 3) and 5 patients of ECMS group discontinued treatment because of same reasons (n = 1, 4). Total symptom scores were significantly decreased after treatment of 8 session in both treatment groups (13.4 ± 6.6 vs. 4.3 ± 4.0 for BF, p = 0.009; 14.9 ± 5.6 vs. 3.4 ± 4.0 for ECMS, p < 0.001). Bowel movements per week were also significantly increased after treatment in both groups (median 2 vs. 7 for BF, p = 0.035; median 2 vs. 7 for ECMS, p = 0.008). Thirteen out of 15 patients showed response in BF group and 12 out of 14 showed good response in ECMS group. No adverse effects in both groups. Conclusions: ECMS is as effective as BF for the treatment of PFD. Long‐term effect of ECMS for the patients with pelvic floor dyssynergia need to be evaluated in the near future. 相似文献
12.
13.
In this observational study, we sought to assess the usefulness of pH values from residuals in intensive care unit (ICU) patients with small-bore feeding tubes. A review of the literature demonstrated that most critically ill patients were excluded in previous studies on gastric pH testing, suggesting that pH testing in critical care is not warranted. Our results demonstrated that 21% of intestinal testing and 64% of gastric testing yielded potential misinformation to the bedside nurse with regards to possible tube location. In conclusion, pH testing for small-bore tube placement and maintenance was not deemed meaningful in our critical care unit. 相似文献
14.
15.
大狼毒三萜类化学成分的研究 总被引:3,自引:0,他引:3
自大戟科(Euphorbiaceae)植物大狼毒(Euphorbia nematocypha Hand—Mazz)根的乙醇提取物的苯溶解部分,经20%AgNO3硅胶层析,分离得到七个三萜类成分。根据光谱(IR,EIMS,1H—NMR和13C—NMR)和化学方法,确定其中一个化合物为新化合物,命名为大狼毒醇(nematocyphol,Ⅳa),其它化合物为已知物:印度荆芥醇乙酸酯(nepehinol acetate Ⅰ),日尔曼醇乙酸酯(germanicol acetate Ⅱ),大戟醇(euphol,Ⅲ),蒲公英醇(taraxasterol,Ⅴa),24-亚甲基环阿尔廷醇(24-methylenecycloartanol,Ⅴa)和印度荆芥醇(nepehinol,Ⅶa)。这些化合物均为首次从大狼毒中得到。 相似文献
16.
Zhao P Qin ZL Ke JS Lu Y Liu M Pan W Zhao LJ Cao J Qi ZT 《第二军医大学学报》2005,26(10):1167-1167
SARS-CoV isa newly identified coronavirus that causes severe acute respiratory syndrome (SARS). Currently, there is no effective method available for prophylaxis and treatment of SARS-CoVinfections. In the present study, the influence of small interfering RNA (siRNA) on SARS-CoV nucleocapsid (N) protein expression was detected in cultured cells and mouse muscles. Four siRNA expression cassettes driven by mouse U6 promoter targeting SARS-CoV N gene were prepared, and their inhibitory effects on expression of N and enhanced green fluorescence protein (EGFP) fusion protein were observed. 相似文献
17.
Low-artifact intravascular devices: MR imaging evaluation 总被引:2,自引:0,他引:2
Teitelbaum GP; Ortega HV; Vinitski S; Stern H; Tsuruda JS; Mitchell DG; Rifkin MD; Bradley WG Jr 《Radiology》1988,168(3):713-719
Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible. 相似文献
18.
Wijkstrom-Frei C El-Chemaly S Ali-Rachedi R Gerson C Cobas MA Forteza R Salathe M Conner GE 《American journal of respiratory cell and molecular biology》2003,29(2):206-212
The lactoperoxidase (LPO) antibiotic system is a well-characterized component of mammary and salivary gland secretions. Because LPO has been shown to function in ovine airways, human airway tissue and secretions were examined for the presence of LPO and its substrate, the anion thiocyanate (SCN-). In addition, human airway secretions were tested for LPO-mediated antibacterial activity, and LPO's activity was assessed against some human airway pathogens. The data showed that normal human airway secretions contained LPO enzyme activity (0.65 +/- 0.09 microg/mg secreted protein; n = 17), and Western blots of secretions demonstrated bands of the expected sizes for LPO. LPO mRNA was detected in trachea by sequencing PCR-amplified cDNA. SCN-, LPO's substrate, was present in undiluted airway secretions at concentrations sufficient for LPO catalysis (0.46 +/- 0.19 mM; n = 8), and diluted secretions contained antibacterial activity with LPO-like properties. Immunocytochemistry localized LPO to submucosal glands in human bronchi. Finally, as expected based on the known antibacterial spectrum of the LPO system, airway secretions showed LPO-dependent activity against Pseudomonas aeruginosa. In addition, the airway LPO system was shown to be effective against Burkholderia cepacia and Haemophilus influenzae. Thus, a functional LPO system exists in human airways and may contribute to airway host defense against infection. 相似文献
19.
20.