全文获取类型
收费全文 | 705459篇 |
免费 | 49923篇 |
国内免费 | 1296篇 |
专业分类
耳鼻咽喉 | 9166篇 |
儿科学 | 23310篇 |
妇产科学 | 17606篇 |
基础医学 | 110480篇 |
口腔科学 | 19964篇 |
临床医学 | 63809篇 |
内科学 | 134461篇 |
皮肤病学 | 16161篇 |
神经病学 | 49598篇 |
特种医学 | 25755篇 |
外国民族医学 | 76篇 |
外科学 | 104564篇 |
综合类 | 14820篇 |
现状与发展 | 2篇 |
一般理论 | 160篇 |
预防医学 | 51400篇 |
眼科学 | 16329篇 |
药学 | 53960篇 |
3篇 | |
中国医学 | 2361篇 |
肿瘤学 | 42693篇 |
出版年
2021年 | 5443篇 |
2018年 | 7871篇 |
2017年 | 6117篇 |
2016年 | 6823篇 |
2015年 | 7555篇 |
2014年 | 10273篇 |
2013年 | 15393篇 |
2012年 | 20516篇 |
2011年 | 21511篇 |
2010年 | 12747篇 |
2009年 | 11949篇 |
2008年 | 20007篇 |
2007年 | 21527篇 |
2006年 | 21921篇 |
2005年 | 20468篇 |
2004年 | 20012篇 |
2003年 | 18957篇 |
2002年 | 18479篇 |
2001年 | 36343篇 |
2000年 | 36921篇 |
1999年 | 30405篇 |
1998年 | 7885篇 |
1997年 | 6671篇 |
1996年 | 6976篇 |
1995年 | 6632篇 |
1994年 | 6102篇 |
1993年 | 5595篇 |
1992年 | 22983篇 |
1991年 | 22953篇 |
1990年 | 22335篇 |
1989年 | 22101篇 |
1988年 | 20056篇 |
1987年 | 19428篇 |
1986年 | 18484篇 |
1985年 | 17325篇 |
1984年 | 12704篇 |
1983年 | 10748篇 |
1982年 | 5923篇 |
1979年 | 11522篇 |
1978年 | 8135篇 |
1977年 | 6839篇 |
1976年 | 6602篇 |
1975年 | 7271篇 |
1974年 | 8503篇 |
1973年 | 8147篇 |
1972年 | 7661篇 |
1971年 | 7129篇 |
1970年 | 6881篇 |
1969年 | 6307篇 |
1968年 | 5784篇 |
排序方式: 共有10000条查询结果,搜索用时 34 毫秒
901.
902.
903.
Mark Sisco MD ; Jerome D. Chao MD ; Injoong Kim MD ; Jon E. Mogford PhD ; Tanya N. Mayadas PhD ; Thomas A. Mustoe MD 《Wound repair and regeneration》2007,15(4):566-571
The Mac-1 integrin is an important mediator of migration and inflammatory activation of neutrophils and monocytes. However, the role of Mac-1 in modulating macrophage emigration and activation and its subsequent impact on cutaneous wound healing have not been fully elucidated. To examine the significance of Mac-1 to murine wound healing, we measured epithelialization and granulation tissue formation in partial-thickness ear wounds and full-thickness head wounds, respectively, in Mac-1-deficient mice. Wounds were histologically analyzed at postwounding days 3, 5, and 7. The gap measured between the leading edges of inward-migrating granulation tissue was significantly increased in knockout mice compared with control animals at day 5 (3.8+/-0.3 vs. 2.6+/-0.5 mm; p<0.001) and day 7 (2.2+/-0.4 vs. 0.96+/-0.73 mm; p=0.005). Epithelial gap measurements were also increased in knockout mice vs. wild-type controls at days 3 (0.62+/-0.02 vs. 0.54+/-0.07 mm; p<0.05) and 5 (0.58+/-0.06 vs. 0.39+/-0.08 mm; p<0.001). Immunohistochemistry showed equal numbers of macrophages in knockout and control wounds. These findings show that Mac-1 is required for normal wound healing but that the attenuation in the deposition of granulation tissue and wound epithelialization in Mac-1 knockout mice is not associated with decreased monocyte migration into the wound. 相似文献
904.
M. Mizuguchi H. Yamanouchi T. Ichiyama M. Shiomi 《Acta neurologica Scandinavica》2007,115(S186):45-56
Acute encephalopathy is the most serious complication of pediatric viral infections, such as influenza and exanthem subitum. It occurs worldwide, but is most prevalent in East Asia, and every year several hundreds of Japanese children are affected by influenza-associated encephalopathy. Mortality has recently declined, but is still high. Many survivors are left with motor and intellectual disabilities, and some with epilepsy. This article reviews various syndromes of acute encephalopathy by classifying them into three major categories. The first group caused by metabolic derangement consists of various inherited metabolic disorders and the classical Reye syndrome. Salicylate is a risk factor of the latter condition. The second group, characterized by a systemic cytokine storm and vasogenic brain edema, includes Reye-like syndrome, hemorrhagic shock and encephalopathy syndrome, and acute necrotizing encephalopathy. Non-steroidal anti-inflammatory drugs, such as diclofenac sodium and mephenamic acid, may aggravate these syndromes. Severe cases are complicated by multiple organ failure and disseminated intravascular coagulation. Mortality is high, although methylprednisolone pulse therapy may be beneficial in some cases. The third group, characterized by localized edema of the cerebral cortex, has recently been termed acute encephalopathy with febrile convulsive status epilepticus, and includes hemiconvulsion-hemiplegia syndrome and acute infantile encephalopathy predominantly affecting the frontal lobes. Theophylline is a risk factor of these syndromes. The pathogenesis is yet to be clarified, but an increasing body of evidence points to excitotoxicity and delayed neuronal death. 相似文献
905.
Mohammed N Islam Indraneel Bhattacharyya Junu Ojha Karen Bober Donald M Cohen James G Green 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(4):501-509
Hemifacial hypertrophy (HFH) is rare and characterized by unilateral enlargement of the head and teeth. Hemifacial hypertrophy is classified as true HFH (THFH) with unilateral enlargement of the viscerocranium, and partial HFH (PHFH) in which not all structures are enlarged. We present a case of THFH and compare and contrast it with a case of PHFH. Hemifacial hypertrophy may cover a wide spectrum of defects or may involve only muscle or bone. Myohyperplasia, reported previously as a separate syndrome, may actually represent a forme fruste of PHFH or THFH. The PHFH patient lead a healthy, normal life without significant psychosocial problems and was reluctant to accept his deformity. Contrastingly, the THFH patient had significant social stigma and compromised health together with major aesthetic morbidity. Treatment planning in THFH is arduous and involves multiple modalities. Therefore, it is imperative to differentiate THFH and PHFH for better understanding and management of the condition. 相似文献
906.
Patrick N Smith Jeffrey R Balzer Mustafa H Khan Rick A Davis Donald Crammond William C Welch Peter Gerszten Robert J Sclabassi James D Kang William F Donaldson 《The spine journal》2007,7(1):83-87
BACKGROUND CONTEXT: Intraoperative somatosensory evoked potential (SSEP) monitoring has been shown to reduce the incidence of new postoperative neurological deficits in scoliosis surgery. However, its usefulness during cervical spine surgery remains a subject of debate. PURPOSE: To determine the utility of intraoperative SSEP monitoring in a specific patient population (those with cervical radiculopathy in the absence of myelopathy) who underwent anterior cervical discectomy and fusion (ACDF) surgery. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: A total of 1,039 nonmyelopathic patients who underwent single or multilevel ACDF surgery. The control group (462 patients) did not have intraoperative SSEP monitoring, whereas the monitored group (577 patients) had continuous intraoperative SSEP monitoring performed. OUTCOME MEASURE: A new postoperative neurological deficit. METHODS: SSEP tracings were reviewed for all 577 patients in the monitored group and all significant signal changes were noted. Medical records were reviewed for all 1,039 patients to determine if any new neurological deficits developed in the immediate postoperative period. RESULTS: None of the patients in the control group had any new postoperative neurological deficits. In the monitored group there were six instances of transient SSEP changes (1 due to suspected carotid artery compression; 5 thought to be due to transient hypotension) which resolved with the appropriate intraoperative intervention (repositioning of retractors; raising the arterial blood pressure). Upon waking up from anesthesia, one patient in the monitored group had a new neurological deficit (partial central cord syndrome) despite normal intraoperative SSEP signals. CONCLUSIONS: ACDF appears to be a safe surgical procedure with a low incidence of iatrogenic neurological injury. Transient SSEP signal changes, which improved with intraoperative interventions, were not associated with new postoperative neurological deficits. An intraoperative neurological deficit is possible despite normal SSEP signals. 相似文献
907.
L. C. Willcocks A. N. Chaudhry J. C. Smith S. Ojha R. Doffinger C. J. E. Watson K. G. C. Smith 《American journal of transplantation》2007,7(8):2006-2011
Different immunosuppressant regimens vary in their effects on antibody responses to vaccination. The combination of prednisolone and azathioprine has only a minor effect, whereas the addition of ciclosporin attenuates protective antibody responses to influenza vaccination. The effect of sirolimus, a new immunosuppressant, on vaccine responses has been little studied. Thirty-two hepatic or renal transplant patients randomized to calcineurin inhibitor-based or sirolimus-based immunosuppression were vaccinated against influenza and pneumococcus. Following tri-valent influenza vaccination, a similar rise in antibody titer occurred in sirolimus and calcineurin inhibitor (CNI) treated patients, though sirolimus treated patients developed a 'protective' titer to more influenza antigens. The pneumococcal polysaccharide vaccine was equally effective in both groups. Hence, vaccination guidelines in place for CNI treated patients are likely to be appropriate for transplant recipients maintained on sirolimus. 相似文献
908.
D. M. Richards N. Zhang S. L. Dalheimer D. L. Mueller 《American journal of transplantation》2007,7(10):2269-2278
To investigate the mechanism of CD4(+) T-cell help during the activation and differentiation of directly alloreactive CD8(+) T cells, we examined the development of obliterative airways disease (OAD) following transplantation of airways into fully mismatched recipient mice deficient in CD4(+) T cells. BALB/c trachea allografts became fibrosed significantly less frequently in B6 CD4(-/-) recipients as compared to wildtype controls. Furthermore, class I-directed cytotoxicity failed to develop in the absence of CD4(+) T cells. The infiltration of graft tissue by primed L(d)-specific directly alloreactive 2C CD8(+) T cells was not found to depend on the presence of CD4(+) T cells. Nevertheless, graft-infiltrating 2C CD8(+) T cells failed to express CD69 and granzyme B when CD4(+) T-cell help was unavailable. Importantly, reconstitution of B6 CD4(-/-) recipient mice with graft peptide-specific TCR-Tg CD4(+) T cells (OT-II or TEa) capable of recognizing antigen only on recipient APC allowed for full expression of CD69 and granzyme B by the directly alloreactive CD8(+) T cells and restored the capacity of recipients to reject their allografts. These results demonstrate that indirectly alloreactive CD4(+) T cells ensure the optimal activation and differentiation of graft-infiltrating directly alloreactive CD8(+) T cells independent of donor APC recognition. 相似文献
909.
G. N. Smith Jr E. A. Mickler K. K. Payne J. Lee M. Duncan J. Reynolds B. Foresman D. S. Wilkes 《American journal of transplantation》2007,7(7):1856-1861
Parenchymal disease in the allograft lung is associated with interstitial remodeling believed to be mediated by matrix metalloproteinases (MMPs). Recent studies suggest high levels of MMP-9 are associated with bronchiolitis obliterans syndrome (BOS) in lung transplant recipients. Since BOS occurs late in the posttransplant period and may be preceded by episodes of acute rejection or infection, which are associated with interstitial remodeling, we examined MMP profiles in allograft bronchoalveolar lavage (BAL) fluid in the early posttransplant period (preceding BOS). Gelatin zymography, protein array analysis and specific ELISA on BAL fluids from transplanted lungs indicated that MMP-8, MMP-9 and TIMP-1 were strongly expressed in allograft BAL fluid from stable patients, or those with infection or rejection compared to BAL fluid from normal volunteers. Elevated expression of MMP-8, MMP-9 and TIMP-1 occurred early, and was sustained for the 3.2 years covered in this study. Elevations of MMP-8, MMP-9 and TIMP-1 in the first 2 years posttransplant appear to be associated with lung transplantation itself, and not infection or rejection. These data suggest that ongoing and clinically silent MMP activity could perpetuate progressive disease in the allograft lung. 相似文献
910.
A. Varkey N. C. Tan R. Girotto W. C. Tang Y. T. Liu H. C. Chen 《ANZ journal of surgery》2007,77(Z1):A62-A62
Purpose Post operative monitoring is crucial for the success of microsurgical free tissue transfer. Sophisticated and expensive methods are available for monitoring. We propose a novel technique using digital photography and the internet as a reliable and cost effective method to monitor free tissue transfers. Methods 163 micro‐vascular procedures were monitored using this technique over 8 months. Serial photographs taken to show flap color. Capillary refill time, pin prick‐ bleed time and color and hand held Doppler signal was recorded in the movie mode of a standard 5 mega pixel camera with duration of 15 seconds. Data was sent to the surgeon at regular intervals and or as deemed necessary. Results Analysis of the 67 cases is presented. 5 re‐explorations were done. The early diagnosis of venous congestion was possible using this technique. Timely intervention contributed to the success of the re‐explorations and these flaps could be salvaged. The file size of images was in the range of 1 MB–6 MB. The file size of an entire set of images ranged about 7 MB–9 MB. These were sent across the ADSL internet lines. Conclusion The use of the digital images and the internet allow reconstructive surgeons to have a reliable picture of the state of their free tissue transfers. This permits decrease in observer error and saves valuable time which otherwise needs to be spent to verify situations of doubt and offers an ideal solution to the logistic problem of having to visit the patient in case of doubt. 相似文献