全文获取类型
收费全文 | 50709篇 |
免费 | 2677篇 |
国内免费 | 421篇 |
专业分类
耳鼻咽喉 | 536篇 |
儿科学 | 961篇 |
妇产科学 | 1432篇 |
基础医学 | 6192篇 |
口腔科学 | 1866篇 |
临床医学 | 3859篇 |
内科学 | 13999篇 |
皮肤病学 | 1035篇 |
神经病学 | 4374篇 |
特种医学 | 1404篇 |
外科学 | 7690篇 |
综合类 | 338篇 |
一般理论 | 10篇 |
预防医学 | 2810篇 |
眼科学 | 791篇 |
药学 | 2844篇 |
中国医学 | 197篇 |
肿瘤学 | 3469篇 |
出版年
2023年 | 337篇 |
2022年 | 311篇 |
2021年 | 1625篇 |
2020年 | 881篇 |
2019年 | 1285篇 |
2018年 | 1734篇 |
2017年 | 1157篇 |
2016年 | 1272篇 |
2015年 | 1472篇 |
2014年 | 1988篇 |
2013年 | 2614篇 |
2012年 | 4041篇 |
2011年 | 4000篇 |
2010年 | 2286篇 |
2009年 | 2006篇 |
2008年 | 3407篇 |
2007年 | 3544篇 |
2006年 | 3298篇 |
2005年 | 3264篇 |
2004年 | 2962篇 |
2003年 | 2709篇 |
2002年 | 2400篇 |
2001年 | 443篇 |
2000年 | 362篇 |
1999年 | 437篇 |
1998年 | 439篇 |
1997年 | 383篇 |
1996年 | 320篇 |
1995年 | 310篇 |
1994年 | 247篇 |
1993年 | 200篇 |
1992年 | 203篇 |
1991年 | 155篇 |
1990年 | 148篇 |
1989年 | 123篇 |
1988年 | 94篇 |
1987年 | 79篇 |
1986年 | 103篇 |
1985年 | 99篇 |
1984年 | 95篇 |
1983年 | 76篇 |
1982年 | 104篇 |
1981年 | 68篇 |
1980年 | 74篇 |
1979年 | 52篇 |
1978年 | 63篇 |
1977年 | 44篇 |
1976年 | 41篇 |
1974年 | 33篇 |
1973年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 29 毫秒
91.
Luciano Potena Francesco Grigioni Gaia Magnani Paolo Ortolani Fabio Coccolo Simonetta Sassi Koen Koessels Cinzia Marrozzini Antonio Marzocchi Samuela Carigi Anna C. Musuraca Antonio Russo Carlo Magelli Angelo Branzi 《American journal of transplantation》2005,5(9):2258-2264
Although observational studies suggest that hyperhomocysteinemia may be a risk factor for coronary allograft vasculopathy (CAV), prospective data on homocysteine-lowering interventions and CAV development are lacking. We, therefore, randomized 44 de novo heart transplant (HT) recipients to 15 mg/day of 5-methyl-tetrahydrofolate (n=22), or standard therapy (control group, n=22) to investigate the effect of homocysteine lowering on the change in coronary intimal hyperplasia during the first 12 months after transplant, as detected by intra-vascular ultrasound (IVUS). Although 12 months after HT, homocysteinemia was lower in folate-treated patients (p<0.001), coronary intimal area increased similarly in the two groups (p>0.4). Conversely, hypercholesterolemia and cytomegalovirus infection were both associated with increased intimal hyperplasia (p<0.04), independently from folate intake. Sub-group analysis revealed that folate therapy reduced intimal hyperplasia in patients with hyperhomocysteinemia before randomization (n=19; p=0.02), but increased intimal hyperplasia in patients with normal homocysteine plasma concentrations (p=0.02). This bimodal effect of folate therapy persisted significantly after adjusting for cytomegalovirus infection and hypercholesterolemia. Despite effective in prevent hyperhomocysteinemia after heart transplantation, folate therapy does not seem to affect early CAV onset. However, sub-group analysis suggests that folate therapy may delay CAV development only in patients with baseline hyperhomocysteinemia, while may favor CAV progression in recipients with normal baseline homocysteinemia. 相似文献
92.
Dario Giugliano Antonio Ceriello Katherine Esposito 《Journal of the American College of Cardiology》2006,48(4):677-685
Reducing the incidence of coronary heart disease with diet is possible. The main dietary strategies include adequate omega-3 fatty acids intake, reduction of saturated and trans-fats, and consumption of a diet high in fruits, vegetables, nuts, and whole grains and low in refined grains. Each of these strategies may be associated with lower generation of inflammation. This review examines the epidemiologic and clinical evidence concerning diet and inflammation. Dietary patterns high in refined starches, sugar, and saturated and trans-fatty acids, poor in natural antioxidants and fiber from fruits, vegetables, and whole grains, and poor in omega-3 fatty acids may cause an activation of the innate immune system, most likely by an excessive production of proinflammatory cytokines associated with a reduced production of anti-inflammatory cytokines. The whole diet approach seems particularly promising to reduce the inflammation associated with the metabolic syndrome. The choice of healthy sources of carbohydrate, fat, and protein, associated with regular physical activity and avoidance of smoking, is critical to fighting the war against chronic disease. Western dietary patterns warm up inflammation, while prudent dietary patterns cool it down. 相似文献
93.
AIM: The authors report an alternative procedure to carotid endarterectomy with internal carotid artery (ICA) segmental resection and end-to-end anastomosis associated with temporary shunt and venous patch angioplasty. Design: prospective cohort study. METHODS: Between May 1995 and December 2004, 192 patients underwent 200 primary CEAs for significant ICA stenosis. There were 131 men and 61 women with a mean age of 72.4+/-8.4 years. The indications for CEA were asymptomatic lesions in 51.5%, transient ischemic attack in 27.5% and stroke in 21%. RESULTS: The combined early morbidity and mortality rate was 2%. Two patients died, one due to fatal intracerebral hemorrhage and the second patient died of acute mesenteric ischemia. Neurological complications occurred in 2 patients, including 1 TIA and 1 nondisabling cerebrovascular accident. Non-neurological complications occurred in 26 patients (13.5%). Seventeen patients (8.8%) developed hypertension, 3 neck hematomas (1.5%) required surgical evacuation, 1 patient had reversible supraventricular arrhythmia (0.5%) and 1 patient had pneumonia (0.5%). Furthermore, 1 asymptomatic carotid occlusion was identified (0.5%) and 3 patients suffered permanent cranial nerve injury (1.5%). Mean follow-up was 45.7 months and there were 41 late deaths (21.8%). Survival rates at 1 and 5 years were 96.7+/-1.2% and 73.58+/-4.2%, respectively. CONCLUSIONS: CEA with ICA shortening and reanastomosis is a safe and reliable procedure without any increase in morbidity or mortality. 相似文献
94.
Edward Black Jason Niamat Srikanth Boddu Antonio Martin-Ucar John P Duffy William Ellis Morgan Francis David Beggs 《European journal of cardio-thoracic surgery》2006,29(2):244-247
OBJECTIVE: There are limited and conflicting data available concerning the incidence of inadvertent splenectomy and its impact on the outcome in patients who have undergone oesophagectomy. The aim of this study is to identify the factors associated with a likelihood of inadvertent splenectomy and its influence on early and long-term outcome in patients having oesophagectomy for oesophageal carcinoma. METHODS: A consecutive series of 738 oesophagectomies performed between 1991 and 2004 was analysed. In our practice, the spleen was removed only if damaged intraoperatively. Routine chemo- and immunoprophylaxis would subsequently be used. Multivariate analysis with logistic and Cox models determined significant variables. RESULTS: Of the 738 oesophagectomies, 48 (6.5%) had splenectomy. Neoadjuvant chemotherapy was administered to a minority of patients; none subsequently had splenectomy. There were significant differences between types of operation (Ivor-Lewis 18 (9.0%), left thoracolaparotomy 14 (9.9%) and left thoracophrenotomy 15 (3.9%), p=0.01). Splenectomy was more common with advanced N stage disease (OR=0.44 [0.20-0.95]; p=0.04). Splenectomy resulted in more blood transfusions (median, 2 units vs 0 units; p=0.03) more anastomotic leaks (7 [14.6%] vs 42 [6.1%]; p=0.02) but not an increase in pulmonary complications (p=0.64) or in-hospital mortality (1 [4.6%] vs 37 [5.4%]; p=0.30). Splenectomy did not significantly affect median survival (551 [332-770] days vs 627 [554-700] days; p=0.63). CONCLUSION: Although inadvertent splenectomy increased the morbidity of oesophagectomy, it did not impair survival. Type of operation and advanced N stage are important risks for splenectomy. Though best avoided, most of the consequences of splenectomy can be managed. An unexpected relationship between splenectomy and anastomotic leaks needs further investigation. 相似文献
95.
96.
Antonio Vidaller Fernando Guadarrama Luis Llorente Juan Pablo Méndez Fernando Larrea Antonio R. Villa Donato Alarcón-Segovia 《Journal of clinical immunology》1992,12(3):210-215
We studied NK cell function in eight patients with pathological hyperprolactinemia by measuring51Cr release by K562 cells exposed to their mononuclear cells and found it decreased compared to normal controls (P<0.01). Bromocriptine (BrC) treatment corrected NK function but also made it more efficient at 12:1 than at 25:1 or 50:1 effector:target ratios (ANOVA;P=0.01). The study of NK cell function in agarose revealed that its decrease in hyperprolactinemia is due to their low active binding to target cells, active killing, and recycling capacity. BrC tended to correct them but also increased recycling capacity to levels higher than those of controls (P<0.05). Sequential studies in three hyperprolactinemic patients before and after BrC showed correction of NK function within 1 week but its increased efficiency at the 12:1 effector:target ratio required 8 weeks. We conclude that hyperprolactinemia decreases NK cell function. BrC corrects this by decreasing prolactin levels but also makes NK function more efficient by increasing the capacity of NK cells to recycle after killing. 相似文献
97.
98.
J A San Román I Vilacosta J Zamorano C Almería F J Cortés E Iturralde L Sánchez Harguindey 《Revista espa?ola de cardiología》1992,45(3):219-221
Three cases with suspected pulmonary artery embolism are presented, in which transesophageal echocardiography showed a mass in the right pulmonary artery consistent with thrombus. The relevant diagnostic contributions of transesophageal echocardiography are discussed. 相似文献
99.
Stefano Tamburin Antonio Fiaschi Domenico Idone Piergiorgio Lochner Paolo Manganotti Giampietro Zanette 《Movement disorders》2003,18(11):1316-1324
Hyperexcitability of the motor system has been reported in Parkinson's disease (PD). We evaluate how cutaneous afferents modulate motor excitability in PD patients and whether abnormal modulation is correlated to parkinsonian symptoms. Digital stimulation causes abnormal enhancement of motor responses in patients. This effect may be one of the features of motor hyperexcitability in PD. Cutaneomotor hyperexcitability correlates with clinical scores, suggesting that abnormal processing of cutaneous inputs might contribute to the pathogenesis of parkinsonian symptoms. 相似文献
100.
Eric Vivier Antonio J. da Silva Melissa Ackerly Herbert Levine Christopher E. Rudd Paul Anderson 《European journal of immunology》1993,23(8):1872-1876
The CD16: ζ: γ receptor complex allows natural killer (NK) cells to recognize and eliminate antibody-coated target cells. Whereas the ectodomain of CD16 is the receptor for Fcγ domains of immunoglobulins, disulfide-linked homo- and heterodimers composed of ζ and γ are required for the cell surface expression, and signal transduction properties of the complex. Engagement of CD16 activates the tyrosine kinase pathway, which induces the tyrosine phosphorylation of several substrates, including the ζ subunit and the phospholipase C γ-1 and γ-2 isoforms. Here we show that CD 16 stimulation of either peripheral blood NK cells, leukemic NK cells, or Jurkat transformants expressing a CD16:ζ:γ receptor complex, results in the tyrosine phosphorylation of a 70 kDa ζ-associated protein (pp70). Similarly, a 70-kDa ζ-associated phosphoprotein in T cells has been shown to be a tyrosine kinase (ZAP-70). Peptide mapping analysis indicates that the 70-kDa ζ-associated phosphoproteins from T cells and NK cells are structurally indistinguishable. We conclude that the CD16:ζ:γ complex may use a ZAP-70-related non-receptor tyrosine kinase, in the CD16 signaling cascade leading to NK cell activation. 相似文献