全文获取类型
收费全文 | 8095篇 |
免费 | 531篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 187篇 |
妇产科学 | 114篇 |
基础医学 | 1293篇 |
口腔科学 | 222篇 |
临床医学 | 852篇 |
内科学 | 1481篇 |
皮肤病学 | 143篇 |
神经病学 | 911篇 |
特种医学 | 300篇 |
外科学 | 1163篇 |
综合类 | 80篇 |
一般理论 | 4篇 |
预防医学 | 516篇 |
眼科学 | 168篇 |
药学 | 588篇 |
中国医学 | 19篇 |
肿瘤学 | 518篇 |
出版年
2023年 | 49篇 |
2022年 | 38篇 |
2021年 | 194篇 |
2020年 | 100篇 |
2019年 | 143篇 |
2018年 | 167篇 |
2017年 | 153篇 |
2016年 | 195篇 |
2015年 | 245篇 |
2014年 | 302篇 |
2013年 | 380篇 |
2012年 | 568篇 |
2011年 | 531篇 |
2010年 | 315篇 |
2009年 | 297篇 |
2008年 | 447篇 |
2007年 | 481篇 |
2006年 | 492篇 |
2005年 | 452篇 |
2004年 | 397篇 |
2003年 | 332篇 |
2002年 | 297篇 |
2001年 | 197篇 |
2000年 | 158篇 |
1999年 | 163篇 |
1998年 | 82篇 |
1997年 | 58篇 |
1996年 | 42篇 |
1995年 | 43篇 |
1993年 | 29篇 |
1992年 | 103篇 |
1991年 | 80篇 |
1990年 | 83篇 |
1989年 | 81篇 |
1988年 | 71篇 |
1987年 | 76篇 |
1986年 | 52篇 |
1985年 | 62篇 |
1984年 | 51篇 |
1983年 | 32篇 |
1982年 | 34篇 |
1981年 | 31篇 |
1980年 | 32篇 |
1979年 | 37篇 |
1978年 | 34篇 |
1976年 | 29篇 |
1974年 | 32篇 |
1973年 | 33篇 |
1972年 | 31篇 |
1971年 | 36篇 |
排序方式: 共有8679条查询结果,搜索用时 15 毫秒
1.
2.
Very preterm children are at increased risk of reduced processing speed at 5 years of age,predicted by typical complications of prematurity and prenatal smoking 下载免费PDF全文
3.
Jenny U. Johansson Nathaniel S. Woodling Qian Wang Maharshi Panchal Xibin Liang Angel Trueba-Saiz Holden D. Brown Siddhita D. Mhatre Taylor Loui Katrin I. Andreasson 《The Journal of clinical investigation》2015,125(1):350-364
Microglia, the innate immune cells of the CNS, perform critical inflammatory and noninflammatory functions that maintain normal neural function. For example, microglia clear misfolded proteins, elaborate trophic factors, and regulate and terminate toxic inflammation. In Alzheimer’s disease (AD), however, beneficial microglial functions become impaired, accelerating synaptic and neuronal loss. Better understanding of the molecular mechanisms that contribute to microglial dysfunction is an important objective for identifying potential strategies to delay progression to AD. The inflammatory cyclooxygenase/prostaglandin E2 (COX/PGE2) pathway has been implicated in preclinical AD development, both in human epidemiology studies and in transgenic rodent models of AD. Here, we evaluated murine models that recapitulate microglial responses to Aβ peptides and determined that microglia-specific deletion of the gene encoding the PGE2 receptor EP2 restores microglial chemotaxis and Aβ clearance, suppresses toxic inflammation, increases cytoprotective insulin-like growth factor 1 (IGF1) signaling, and prevents synaptic injury and memory deficits. Our findings indicate that EP2 signaling suppresses beneficial microglia functions that falter during AD development and suggest that inhibition of the COX/PGE2/EP2 immune pathway has potential as a strategy to restore healthy microglial function and prevent progression to AD. 相似文献
4.
5.
Duct-associated lymphoid tissue (DALT) of minor salivary glands and mucosal immunity. 总被引:3,自引:0,他引:3 下载免费PDF全文
Minor salivary glands (MSG) play a substantial role in the secretory immunoglobulin A (sIgA)-mediated immunity of the oral cavity. There are two possibilities for the induction of this immunity: (i) an explicitly local antigenic stimulus, or (ii) a remote stimulus as part of the so-called 'common mucosal immune system'. This communication is an attempt to consolidate available evidence in support of both possibilities and to address the former in detail. Although there is strong circumstantial evidence supporting the feasibility of MSG functioning as a part of the common mucosal immune system, direct experimental evidence is yet to emerge. On the other hand, there is increasing structural and physiological evidence in support of MSG serving as a local immunological organ. The purely local response is attributed to the presence of MSG duct-associated lymphoid tissue (DALT), which is comparable to gut- or bronchial-associated lymphoid tissue (GALT or BALT) in origin, tissue organization and function. DALT is accessible to oral antigens by retrograde passage through MSG ducts. Repeated topical antigenic challenging via the oral mucosa may result in the appearance of interacinar plasma cells carrying specific homologous antibodies in MSG. Gut or enteric priming of the same antigen, by passing the oral mucosa by gastric intubation, need not evoke a remote immune response in MSG. Since DALT is more likely to occur in healthy, young growing individuals, who are less likely to undergo bioptic examination of MSG, it has not yet been documented in humans. The physiologically induced DALT is apt to be confused with focal accumulations of lymphoid tissue in pathologically altered MSG, as a consequence of local and some systemic autoimmune diseases. An attempt is made to demarcaate healthy and pathological MSG on the basis of currently available clinical, serological, immunological and genetic evidence. 相似文献
6.
Molecular determinants of cetuximab efficacy. 总被引:17,自引:0,他引:17
Daniel Vallb?hmer Wu Zhang Michael Gordon Dong Yun Yang Jim Yun Oliver A Press Katrin E Rhodes Andy E Sherrod Syma Iqbal Kathleen D Danenberg Susan Groshen Heinz-Josef Lenz 《Journal of clinical oncology》2005,23(15):3536-3544
PURPOSE: To investigate whether mRNA expression levels of cyclin D1 (CCND1), cyclooxygenase 2 (Cox-2), epidermal growth factor receptor (EGFR), interleukin 8 (IL-8), and vascular endothelial growth factor (VEGF), all members of the EGFR signaling pathway, are associated with clinical outcome in patients with EGFR-expressing metastatic colorectal cancer (CRC) treated with cetuximab. PATIENTS AND METHODS: Thirty-nine patients with metastatic CRC, refractory to both irinotecan and oxaliplatin, were enrolled on IMCL-0144 and treated with single-agent cetuximab. The intratumoral mRNA levels of CCND1, Cox-2, EGFR, IL-8, and VEGF were assessed from paraffin-embedded tissue samples using laser-capture microdissection and quantitative real-time polymerase chain reaction. RESULTS: There were 21 women and 18 men with a median age of 64 years (range, 35 to 83 years). Higher gene expression levels of VEGF were associated with resistance to cetuximab (P = .038; Kruskal-Wallis test). The combination of low gene expression levels of Cox-2, EGFR, and IL-8 was significantly associated with overall survival (13.5 v 2.3 months; P = .028; log-rank test). Both findings were independent of skin toxicity that was itself significantly correlated to survival. Patients with a lower mRNA amount of EGFR had a longer overall survival compared with patients that had a higher mRNA amount (7.3 v 2.2 months; P = .09; log-rank test). Patients with lower expression of Cox-2 had a significantly higher rate of grade 2 to 3 skin reactions under cetuximab treatment. CONCLUSION: This pilot study suggests that gene expression levels of Cox-2, EGFR, IL-8, and VEGF in patients with metastatic CRC may be useful markers of clinical outcome in single-agent cetuximab treatment. 相似文献
7.
Stefan Ockert Hardy Schumacher Dittmar Böckler Katrin Malcherek Jochen Hansmann Jens Allenberg 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(6):725-730
Background and aims Since the introduction of endovascular aortic aneurysm repair (EVAR) for aortic aneurysms, the number of juxtarenal aortic
aneurysms (JRA) has been growing steadily due to selection bias (neck morphology for EVAR). This case-match study compares
the perioperative outcome and midterm results of suprarenally clamped JRA with infrarenal aortic aneurysms (AAA).
Methods From 1997 to 2004, patients who received open surgery with suprarenal clamping for JRA were included in the study and compared
to matched patients with infrarenal clamping (AAA). Measurements analyzed were the in-hospital mortality and morbidity. Midterm
results were obtained through clinical investigation and magnetic resonance angiography imaging.
Results Thirty-five patients (mean age, 68.4 years; 30 male and 5 female) received suprarenal cross-clamping for JRA. The overall
in-hospital mortality for JRA and for the controls (AAA) with elective aortic repair was 4.5% (6.1% JRA; 3% AAA, p = 0.058). The morbidity of JRA was elevated according to the rate of pulmonary complications (p = 0.021) and the need for re-operation (p = 0.019). The mean follow-up time was 2.3 years (range, 8–96 months). At follow-up, 28 patients (80%) from the JRA group
and 29 patients from the AAA group (82.9%) were alive.
Conclusion Open aortic surgery for JRA with the need for suprarenal cross-clamping shows a slightly elevated in-hospital mortality rate
without statistical significance and equal midterm mortality results in comparison with infrarenally clamped aortic aneurysms. 相似文献
8.
Prof. Dr. W. Schroeder 《Basic research in cardiology》1949,15(1-6):24-32
Zusammenfassung Es wird ein für die fortlaufende Blutdruckschreibung an der Karotisschlinge des Hundes entwickeltes Gerät hoher Empfindlichkeit beschrieben, welches bei entlasteter Gefäßwand die Blutdruckänderungen mit automatisch richtiger Wiedergabe der Amplitude durch ein optisches Glasplattenmanometer zur Aufschrift bringt. Die Steuerung des Manometers erfolgt durch eine sich selbsttätig entlastende Membran.Mit 7 Abbildungen 相似文献
9.
10.
1. Studies have been made of the behavior of renal blood flow after partial constriction of the renal artery in twenty-four dogs. 2. When reduction in renal blood flow is produced by partial constriction of the renal artery, a readjustment of flow in the direction of normal occurs within a few minutes, subsequent constriction being again followed by a return of flow toward normal until the artery is markedly constricted. 3. Renal blood flow after marked constriction of the artery becomes extremely susceptible to the vasoconstrictive action of small doses of adrenalin, and flow may cease with larger doses for a considerable period of time. 4. Arterial hypertension of significant degree may follow partial constriction of one renal artery during brief experiments when adrenalin in addition has been administered. 5. Further evidence is presented in favor of the concept that the renal circulation enjoys a control independent of systemic arterial pressure. 相似文献