全文获取类型
收费全文 | 33147篇 |
免费 | 2068篇 |
国内免费 | 265篇 |
专业分类
耳鼻咽喉 | 445篇 |
儿科学 | 598篇 |
妇产科学 | 492篇 |
基础医学 | 4074篇 |
口腔科学 | 1554篇 |
临床医学 | 2724篇 |
内科学 | 8942篇 |
皮肤病学 | 392篇 |
神经病学 | 3348篇 |
特种医学 | 1305篇 |
外科学 | 5282篇 |
综合类 | 93篇 |
一般理论 | 6篇 |
预防医学 | 1395篇 |
眼科学 | 546篇 |
药学 | 1728篇 |
中国医学 | 73篇 |
肿瘤学 | 2483篇 |
出版年
2024年 | 32篇 |
2023年 | 360篇 |
2022年 | 669篇 |
2021年 | 1255篇 |
2020年 | 745篇 |
2019年 | 1023篇 |
2018年 | 1205篇 |
2017年 | 956篇 |
2016年 | 1067篇 |
2015年 | 1130篇 |
2014年 | 1460篇 |
2013年 | 1778篇 |
2012年 | 2776篇 |
2011年 | 2673篇 |
2010年 | 1499篇 |
2009年 | 1363篇 |
2008年 | 2145篇 |
2007年 | 2256篇 |
2006年 | 2029篇 |
2005年 | 1842篇 |
2004年 | 1642篇 |
2003年 | 1495篇 |
2002年 | 1297篇 |
2001年 | 262篇 |
2000年 | 235篇 |
1999年 | 241篇 |
1998年 | 240篇 |
1997年 | 201篇 |
1996年 | 153篇 |
1995年 | 140篇 |
1994年 | 126篇 |
1993年 | 106篇 |
1992年 | 117篇 |
1991年 | 93篇 |
1990年 | 80篇 |
1989年 | 54篇 |
1988年 | 85篇 |
1987年 | 61篇 |
1986年 | 44篇 |
1985年 | 63篇 |
1984年 | 52篇 |
1983年 | 43篇 |
1982年 | 46篇 |
1981年 | 29篇 |
1980年 | 24篇 |
1979年 | 41篇 |
1978年 | 30篇 |
1977年 | 22篇 |
1973年 | 31篇 |
1972年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Erkki Lotspeich Markus Schoene Heinz Gerngroß Roland Schmidt Reinhard Steinmann Marco Ramadani Susanne Gansauge 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(5):559-566
Introduction Postoperative treatment for colorectal cancer depends on tumor stage as defined by the International Union Against Cancer
(UICC). Adjuvant chemotherapy is not recommended in patients without lymph node involvement (UICC stages I and II). As many
as 20–30% of these patients, however, will develop recurrence.
Aims and objectives We conducted this study to determine the presence of disseminated tumor cells in the lymph nodes by quantitative real-time
polymerase chain reaction (QRT-PCR) for cytokeratin 20 (CK20) in an attempt to provide supplementary information compared
to histopathological findings.
Materials and methods Using a standard QRT-PCR assay, we examined primary tumors and 391 lymph nodes from 31 patients with completely resected colorectal
cancer.
Results Of the 31 primary tumors, 29 were positive for CK20 by QRT-PCR.
Discussion An examination of the lymph nodes from the 29 patients with CK20-positive primary tumors revealed that 35 (92.1% sensitivity)
of the 38 histopathologically positive lymph nodes and 54 (16.7%) of the 324 histopathologically negative lymph nodes were
positive by molecular analysis. CK20 expression was detected in 10 (100%) of 10 patients with a histopathologically positive
lymph node status (pN1). In 9 (47.4%) of 19 patients with negative histopathological results (pN0), we detected a CK20 mRNA
signal in at least one lymph node. Whereas eight patients with histopathologically negative lymph nodes could be upstaged
on the basis of the molecular findings, no patient would be downstaged.
Conclusion Our results suggest that QRT-PCR for CK20 is a useful tool for the quantitative detection of micrometastases in the regional
lymph nodes. We introduce a standardized procedure that integrates a molecular diagnostic technique in the clinical staging. 相似文献
92.
93.
94.
95.
96.
To analyse the effect of concomitant cognitive or motor task performance on balance control in Parkinson's disease (PD), we performed a posturographic study in 24 PD patients and in 20 sex- and age-matched control subjects. Postural sway was measured with eyes open (EO) and eyes closed (EC) during quiet stance and during performance of calculation or motor sequence of thumb opposition to the other fingers. No difference of centre of foot pressure (COP) parameters was observed during quiet standing (either EO or EC) between patients and controls, but visual deprivation induced in both groups a worsening of postural stability. COP area was significantly increased in PD patients during dual task performance, whereas no difference of COP path and x-y axes was observed. The effects induced by the performance of cognitive or motor task were significantly more evident in PD patients with clinical evidence of postural instability (presence of prior falls in the history). This study demonstrates that dual task interference on postural control can be observed in PD patients during performance of cognitive as well as motor tasks. The balance deterioration during dual task performance was significantly enhanced in patients with history of prior falls. These findings have some implications for the strategies to be used in reducing the risk of fall in PD. 相似文献
97.
Carla Testorell Carlo Pruneri Luigi Ferini-Strambi Marco Zamperetti Carlo A. Altamura Salvatore Smirne Silvio R. Bareggi 《Human psychopharmacology》1993,8(6):423-428
Serum immunoglobulins and the activity of natural killer (NK) cells of 50 epileptic patients (eight with idiopathic generalized epilepsy and 42 with cryptogenic partial epilepsy) and 28 controls have been studied. The values of IgA, IgG and IgM were the same-in patients and controls. The NK activity in controls was linearly related to the effector-to-target ratio, but this linear relationship was not observed in epileptic patients. The cytotoxic activity of NK cells at the lowest effector-to-target ratio was significantly greater in patients than in controls. This increase was observed in each therapy group. Our results seem to confirm a disturbance of the immune system in epileptic patients and suggest that this modification of cellular immunity is not a drug effect but is related to the illness itself. 相似文献
98.
An 11-year clinical evaluation of leucite-reinforced glass-ceramic crowns: a retrospective study. 总被引:5,自引:0,他引:5
OBJECTIVE: The purpose of this study was to retrospectively evaluate leucite-reinforced glass-ceramic crowns placed over a 6-year period at two different private dental practices. METHOD AND MATERIALS: One hundred twenty-five Empress crowns were placed in 54 patients. The 93 anterior and 32 posterior crowns were evaluated clinically with a mirror and probe, radiographically, and from clinical photographs, in accordance with a modified California Dental Association and Ryge quality evaluation system. The risk of fracture was determined with the Kaplan-Meier survival analysis. RESULTS: Crowns were studied over periods ranging from 4 to 11 years. The probability of survival of the 125 crowns was 95.2% at 11 years (98.9% in the anterior segment and 84.4% in the posterior segment). Six crowns had to be replaced. Most of the 119 successful crowns were rated excellent; Alfa ratings were assigned to 94.2% for color match, 91.6% for porcelain surface, 86.6% for marginal discoloration, and 94.2% for marginal integrity. CONCLUSION: Leucite-reinforced glass-ceramic crowns showed a low clinical failure rate and excellent esthetics after up to 11 years. 相似文献
99.
100.
Simone Maurea Alberto Cuocolo Leonardo Pace Emanuele Nicolai Antonio Nappi Massimo Imbriaco Carmine Morisco Massimo Chiariello Bruno Trimarco Marco Salvatore 《European journal of nuclear medicine and molecular imaging》1993,20(6):502-510
To compare rest-injected thallium-201 (Tl) redistribution and resting technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) myocardial uptake in chronic coronary artery disease (CAD), 15 patients with angiographically proven CAD and left ventricular (LV) dysfunction (ejection fraction 34%±9%) were studied. All patients underwent rest-redistribution Tl and resting 99mTc-MIBI cardiac imaging. Gated 99mTc-MIBI images were also acquired to assess regional LV wall motion (WM). Myocardial segments (n=225) were divided into three groups on the basis of the degree of coronary artery stenosis: group 1 (total occlusion, n=82), group 2 (50%–99% of stenosis, n=84) and group 3 (<50% of stenosis, n=59). WM was significantly worse in groups 1 and 2 compared to group 3 (P<0.001), but no difference was observed between groups 1 and 2. TI and 99mTc-MIBI uptake were significantly lower in groups 1 and 2 compared to group 3 (P < 0.001), and in group 1 compared to group 2 (P<0.001). When TI and 99mTc-MIBI uptake were directly compared, TI uptake was higher than 99mTc-MIBI uptake in group 1 (P<0.001), while no significant difference was observed in groups 2 and 3. Thus, both rest-injected TI redistribution and resting 99mTc-MIBI uptake reflected the severity of coronary artery stenosis in CAD. However, in myocardial segments with total coronary occlusion T1 uptake was significantly higher than 99mTc-MIBI uptake. Our data suggest that rest-injected Tl redistribution cardiac imaging may identify, more accurately than resting 99mTc-MIBI imaging, the presence of viable myocardium in chronic CAD, particularly when the coronary blood flow is severely impaired. 相似文献