全文获取类型
收费全文 | 47466篇 |
免费 | 3602篇 |
国内免费 | 192篇 |
专业分类
耳鼻咽喉 | 567篇 |
儿科学 | 998篇 |
妇产科学 | 976篇 |
基础医学 | 6607篇 |
口腔科学 | 1001篇 |
临床医学 | 4694篇 |
内科学 | 9970篇 |
皮肤病学 | 1078篇 |
神经病学 | 4539篇 |
特种医学 | 1966篇 |
外国民族医学 | 2篇 |
外科学 | 8604篇 |
综合类 | 479篇 |
一般理论 | 76篇 |
预防医学 | 2675篇 |
眼科学 | 935篇 |
药学 | 2797篇 |
中国医学 | 75篇 |
肿瘤学 | 3221篇 |
出版年
2023年 | 421篇 |
2022年 | 872篇 |
2021年 | 1712篇 |
2020年 | 1017篇 |
2019年 | 1345篇 |
2018年 | 1522篇 |
2017年 | 1024篇 |
2016年 | 1199篇 |
2015年 | 1380篇 |
2014年 | 1871篇 |
2013年 | 2179篇 |
2012年 | 3551篇 |
2011年 | 3501篇 |
2010年 | 1946篇 |
2009年 | 1725篇 |
2008年 | 2726篇 |
2007年 | 2783篇 |
2006年 | 2589篇 |
2005年 | 2406篇 |
2004年 | 2224篇 |
2003年 | 2032篇 |
2002年 | 1861篇 |
2001年 | 524篇 |
2000年 | 517篇 |
1999年 | 537篇 |
1998年 | 431篇 |
1997年 | 339篇 |
1996年 | 253篇 |
1995年 | 247篇 |
1994年 | 208篇 |
1993年 | 212篇 |
1992年 | 367篇 |
1991年 | 340篇 |
1990年 | 308篇 |
1989年 | 273篇 |
1988年 | 258篇 |
1987年 | 243篇 |
1986年 | 237篇 |
1985年 | 261篇 |
1984年 | 216篇 |
1983年 | 204篇 |
1982年 | 170篇 |
1981年 | 158篇 |
1980年 | 168篇 |
1979年 | 183篇 |
1978年 | 150篇 |
1977年 | 139篇 |
1976年 | 135篇 |
1974年 | 143篇 |
1972年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Alexander Stoff MD ; Angel A. Rivera PhD ; N. S. Banerjee PhD ; J. Michael Mathis PhD ; Antonio Espinosa-de-los-Monteros MD ; Long P. Le PhD ; Jorge I. De la Torre MD ; Luis O. Vasconez MD ; Thomas R. Broker PhD ; Dirk F. Richter MD ; Mariam A. Stoff-Khalili MD ; David T. Curiel MD PhD 《Wound repair and regeneration》2006,14(5):608-617
Genetically modified keratinocytes and fibroblasts are suitable for delivery of therapeutic genes capable of modifying the wound healing process. However, efficient gene delivery is a prerequisite for successful gene therapy of wounds. Whereas adenoviral vectors (Ads) exhibit superior levels of in vivo gene transfer, their transductional efficiency to cells resident within wounds may nonetheless be suboptimal, due to deficiency of the primary adenovirus receptor, coxsackie-adenovirus receptor (CAR). We explored CAR-independent transduction to fibroblasts and keratinocytes using a panel of CAR-independent fiber-modified Ads to determine enhancement of infectivity. These fiber-modified adenoviral vectors included Ad 3 knob (Ad5/3), canine Ad serotype 2 knob (Ad5CAV-2), RGD (Ad5.RGD), polylysine (Ad5.pK7), or both RGD and polylysine (Ad5.RGD.pK7). To evaluate whether transduction efficiencies of the fiber-modified adenoviral vectors correlated with the expression of their putative receptors on keratinocytes and fibroblasts, we analyzed the mRNA levels of CAR, alpha upsilon integrin, syndecan-1, and glypican-1 using quantitative polymerase chain reaction. Analysis of luciferase and green fluorescent protein transgene expression showed superior transduction efficiency of Ad5.pK7 in keratinocytes and Ad5.RGD.pK7 in fibroblasts. mRNA expression of alpha upsilon integrin, syndecan-1 and glypican-1 was significantly higher in primary fibroblasts than CAR. In keratinocytes, syndecan-1 expression was significantly higher than all the other receptors tested. Significant infectivity enhancement was achieved in keratinocytes and fibroblasts using fiber-modified adenoviral vectors. These strategies to enhance infectivity may help to achieve higher clinical efficacy of wound gene therapy. 相似文献
32.
Tiberiu Ezri Islam Zahalka Deeb Zabeeda Zeev Feldbrin Alexander Eidelman Reuven Zimlichman Benjamin Medalion Shmuel Evron 《Journal canadien d'anesthésie》2006,53(2):139-145
BACKGROUND: We hypothesized that the incidence of hypotension during total knee replacement (TKR) surgery is lower in patients given combined spinal-epidural (CSE) anesthesia vs those receiving epidural anesthesia alone. METHODS: In a prospective study, 80 American Society of Anesthesiologists I-II patients (aged 40-80 yr), undergoing elective TKR surgery were randomly assigned to either CSE anesthesia (CSE, n = 40) or epidural anesthesia alone (Epidural, n = 40). Hemodynamic measurements included oscillometric mean arterial blood pressure (MAP), heart rate (HR), and cardiac index (CI) as determined by thoracic bioimpedance; systemic vascular resistance (SVR) was calculated. Our primary endpoint (outcome) was the number of hypotension episodes (defined as MAP < 70 mmHg). RESULTS: Using univariate analysis, we found no differences between the groups in regards to MAP, HR, CI, or SVR during the perioperative period. The incidence of hypotension was similar in both groups (two patients in each group), as was the incidence of bradycardia (12 patients in CSE, 7 in Epidural; P = 0.2). There were no differences between groups in other hemodynamic measurements including CI and calculated SVR. Analgesia supplementation with fentanyl was more frequently required in the Epidural group (20 vs 6 patients - P = 0.03). CONCLUSION: Combined spinal-epidural anesthesia and epidural anesthesia alone during TKR surgery are associated with the same incidence of hypotension with statistically and clinically similar hemodynamic responses. 相似文献
33.
Robert A. Mischkowski Max J. Zinser Alexander C. Kübler Barbara Krug Ulrich Seifert Joachim E. Zller 《Journal of cranio-maxillo-facial surgery》2006,34(8):478-483
BACKGROUND: An augmented reality tool for computer assisted surgery named X-Scope allows visual tracking of real anatomical structures in superposition with volume rendered CT or MRI scans and thus can be used for navigated translocation of bony segments. METHODS: In a feasibility study X-Scope was used in orthognathic surgery to control the translocation of the maxilla after Le Fort I osteotomy within a bimaxillary procedure. The situation achieved was compared with the pre-operative situation by means of cephalometric analysis on lateral and frontal cephalograms. RESULTS: The technique was successfully utilized in 5 patients. Maxillary positioning using X-Scope was accomplished accurately within a range of 1mm. The tool was used in all cases in addition to the usual intra-operative splints. A stand-alone application without conventional control does not yet seem reasonable. CONCLUSION: Augmented reality tools like X-Scope may be helpful for controlling maxillary translocation in orthognathic surgery. The application to other interventions in cranio-maxillofacial surgery such as Le Fort III osteotomy, fronto-orbital advancement, and cranial vault reshaping or repair may also be considered. 相似文献
34.
35.
Prof. Dr. Alexander Kapp Prof. Dr. Bettina Wedi 《Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete》2006,57(10):854-854
Ohne Zusammenfassung 相似文献
36.
Sina Alexander Debbie M Nathan Melvyn G Korman 《Clinical gastroenterology and hepatology》2006,4(5):661; author reply 661-661; author reply 662
37.
BACKGROUND: Diffuse peritubular capillary (PTC) C4d deposition has been shown to be associated with relatively poor graft outcome. The significance of focal PTC C4d staining in the early post-transplant period is uncertain. METHODS: Sixty-five biopsies from 53 patients with acute rejection were graded (Banff '97 criteria), stained for C4d, monocytes and T cells, and divided into three groups according to PTC C4d: (i) focal C4d (F) (14 biopsies, 14 patients), (ii) diffuse C4d (D) (23 biopsies, 15 patients) and (iii) no C4d (N) (28 biopsies, 24 patients). The three groups were compared with respect to a variety of biopsy and clinical parameters including outcome. RESULTS: The incidence of transplant glomerulitis and glomerular monocyte infiltration were significantly greater in F (64% and 2.0+/-2.0) and D (57% and 3.4+/-2.0) than in N (11% and 0.2+/-0.2). A significantly higher proportion of F (93%) demonstrated acute cellular rejection (Banff '97 grade > or = 1A) than did D (35%). The F and D groups included significantly more females (50 and 67%, respectively) than did N (21%). The percentage of patients with a second or third transplant was higher in F (29%) and D (40%) than in N (8%) (P = 0.0589). The proportion of patients with glomerular filtration rate < 30 ml/min at 12, 24 and 48 months was higher in the D and F groups than in the N, and there was a statistically significant increasing trend in odds of this outcome occurring at 48 months across the three groups (D > F > N group) (P = 0.0416). CONCLUSION: The results suggest that the biopsy findings and clinical course in patients with focal PTC C4d staining are similar to those associated with diffuse C4d. 相似文献
38.
39.
Sarah A. Taylor Jacqueline Benedetti David Schuller Stephen P. Richman Goronwy O. Broun Alexander Hantel 《Investigational new drugs》1993,11(2-3):227-229
Summary Twenty-two patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with piroxantrone 150 mg/m2 intravenously every 21 days. There were no objective responses. The 95% upper confidence bound for response is 15%. Primary toxicity was hematologic. 相似文献
40.
Rapid adenosine release in the nucleus tractus solitarii during defence response in rats: real-time measurement in vivo 总被引:6,自引:3,他引:3
Nicholas Dale Alexander V. Gourine Enrique Llaudet David Bulmer Teresa Thomas† K. Michael Spyer 《The Journal of physiology》2002,544(1):149-160
We have measured the release of adenosine and inosine from the dorsal surface of the brainstem and from within the nucleus tractus solitarii (NTS) during the defence response evoked by hypothalamic stimulation in the anaesthetised rat. At the surface of the brainstem, only release of inosine was detected on hypothalamic defence area stimulation. This inosine signal was greatly reduced by addition of the ecto-5'-nucleotidase inhibitor α,β-methylene ADP (200 μM), suggesting that the inosine arose from adenosine that was produced in the extracellular space by the prior release of ATP. By placing a microelectrode biosensor into the NTS under stereotaxic control we have recorded release of adenosine within this nucleus. By contrast to the brainstem surface, a fast increase in adenosine, accompanied only by a much smaller change in inosine levels, was seen following stimulation of the hypothalamic defence area. The release of adenosine following hypothalamic stimulation was mainly confined to a narrow region of the NTS some 500 μm in length around the level of the obex. Interestingly the release of adenosine was depletable: when the defence reaction was evoked at short time intervals, much less adenosine was released on the second stimulus. Our novel techniques have given unprecedented real-time measurement and localisation of adenosine release in vivo and demonstrate that adenosine is released at the right time and in sufficient quantities to contribute to the cardiovascular components of the defence reaction. 相似文献