全文获取类型
收费全文 | 140481篇 |
免费 | 8651篇 |
国内免费 | 1189篇 |
专业分类
耳鼻咽喉 | 2246篇 |
儿科学 | 2125篇 |
妇产科学 | 2086篇 |
基础医学 | 22374篇 |
口腔科学 | 3621篇 |
临床医学 | 13218篇 |
内科学 | 25192篇 |
皮肤病学 | 4472篇 |
神经病学 | 11403篇 |
特种医学 | 7982篇 |
外科学 | 18488篇 |
综合类 | 644篇 |
现状与发展 | 3篇 |
一般理论 | 34篇 |
预防医学 | 7350篇 |
眼科学 | 3505篇 |
药学 | 12705篇 |
中国医学 | 1628篇 |
肿瘤学 | 11245篇 |
出版年
2023年 | 994篇 |
2022年 | 3026篇 |
2021年 | 4863篇 |
2020年 | 2375篇 |
2019年 | 3331篇 |
2018年 | 4124篇 |
2017年 | 3356篇 |
2016年 | 4417篇 |
2015年 | 6032篇 |
2014年 | 7091篇 |
2013年 | 8340篇 |
2012年 | 12389篇 |
2011年 | 11875篇 |
2010年 | 6846篇 |
2009年 | 5861篇 |
2008年 | 8320篇 |
2007年 | 7822篇 |
2006年 | 7021篇 |
2005年 | 6571篇 |
2004年 | 5689篇 |
2003年 | 4979篇 |
2002年 | 4310篇 |
2001年 | 3295篇 |
2000年 | 3031篇 |
1999年 | 2360篇 |
1998年 | 1008篇 |
1997年 | 762篇 |
1996年 | 574篇 |
1995年 | 505篇 |
1994年 | 455篇 |
1993年 | 394篇 |
1992年 | 850篇 |
1991年 | 813篇 |
1990年 | 740篇 |
1989年 | 652篇 |
1988年 | 550篇 |
1987年 | 540篇 |
1986年 | 412篇 |
1985年 | 428篇 |
1984年 | 303篇 |
1983年 | 228篇 |
1982年 | 160篇 |
1981年 | 193篇 |
1980年 | 153篇 |
1979年 | 276篇 |
1978年 | 199篇 |
1976年 | 152篇 |
1975年 | 172篇 |
1974年 | 169篇 |
1972年 | 146篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla. 总被引:2,自引:0,他引:2
Dirk Mayer Dong-Hyun Kim Elfar Adalsteinsson Daniel M Spielman 《Magnetic resonance in medicine》2006,55(5):974-978
A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner. 相似文献
96.
H J Kim C H Kang Y T Kim S-W Sung J H Kim S M Lee C-G Yoo C-T Lee Y W Kim S K Han Y-S Shim J-J Yim 《The European respiratory journal》2006,28(3):576-580
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
97.
Sung Woo Lee Sung Hyuk Choi Yunsik Hong Wanbae Kim 《European journal of emergency medicine》2006,13(2):117-118
Generally, a computed tomography scan is conducted for the diagnosis of stroke in the emergency department, because these scans are easier and faster in the detection of stroke. If there are no signs of hemorrhage on computed tomography scan, an ischemic stroke is diagnosed and treated accordingly. A magnetic resonance imaging scan may be taken in order to verify ischemic stroke. This process may lead to improper treatment and is time consuming. To address this situation, case studies are presented in which magnetic resonance imaging diffusion-weighted imaging and gradient recalled echo were performed to detect hemorrhagic and ischemic stroke and particularly, subarachnoid hemorrhage, which is undetectable with a computed tomography scan. 相似文献
98.
99.
Twenty-five women receiving sedation for outpatient hysteroscopic polypectomy were injected with 0.25% bupivacaine 10 mL (paracervical group) and another 25 received the same volume of saline (control group) at the cervical fornix. Both groups were given target-controlled propofol sedation during the procedure. More propofol (mg/min) was needed for adequate anesthesia in the control group compared to the paracervical group (6.5 versus 4.6). In addition, the postoperative pain scores were lower in the paracervical group than in the control group. Hemodynamic changes and postoperative side effects were similar in the two groups. This prospective, randomized, double-blind, placebo-controlled study confirmed the effective use of paracervical blocks. This approach has the effect of reducing the amount of intraoperative propofol and decreasing postoperative pain in outpatient hysteroscopic surgery. 相似文献
100.
Tony R Cucuzzella Elva G Delport Nancy Kim Julie Marley Christine Pruitt Anton G Delport 《The spine journal》2006,6(4):364-369
BACKGROUND CONTEXT: Substantial variation exists regarding the use of sedation before interventional spine techniques. Patient preference should play an important role in decision making regarding the need for sedation. However, little is known about patients' anxiety levels before spinal injections and their perceptions about the necessity of sedation. PURPOSE: To determine patient perception for need for sedation before epidural steroid injections and zygapophyseal joint injections. STUDY DESIGN/SETTING: Survey of consecutive spinal injection patients in an outpatient spine center. PATIENT SAMPLE: 500 consecutive lumbar, thoracic, and cervical patients receiving spinal injections. OUTCOME MEASURES: A 12-item questionnaire assessing patients' perceived anxiety before to a spinal injection. METHODS: Subjects were given the questionnaire after their spinal injection. Percentages requesting sedation for a first and potential second procedure were assessed. Additionally, anxiety level and pain rating, location of injection, age, sex, and other medication use were analyzed to determine the effect on the request for sedation. RESULTS: 17% of patients questioned requested sedation before an injection, and 28% would request sedation if they were to have a second injection. CONCLUSIONS: Routine sedation before diagnostic and therapeutic injections is not necessary as the majority of patients would not request sedation before the procedure when given the option. However, in some patients sedation is indicated, and all patients would benefit from educational material on sedation before the injection. 相似文献