全文获取类型
收费全文 | 26698篇 |
免费 | 1363篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 369篇 |
儿科学 | 2082篇 |
妇产科学 | 649篇 |
基础医学 | 3085篇 |
口腔科学 | 497篇 |
临床医学 | 1484篇 |
内科学 | 4951篇 |
皮肤病学 | 1011篇 |
神经病学 | 1210篇 |
特种医学 | 979篇 |
外科学 | 3962篇 |
综合类 | 928篇 |
一般理论 | 10篇 |
预防医学 | 1309篇 |
眼科学 | 1352篇 |
药学 | 2180篇 |
中国医学 | 150篇 |
肿瘤学 | 1921篇 |
出版年
2023年 | 155篇 |
2022年 | 408篇 |
2021年 | 764篇 |
2020年 | 435篇 |
2019年 | 503篇 |
2018年 | 728篇 |
2017年 | 482篇 |
2016年 | 707篇 |
2015年 | 605篇 |
2014年 | 969篇 |
2013年 | 1139篇 |
2012年 | 1613篇 |
2011年 | 1711篇 |
2010年 | 942篇 |
2009年 | 750篇 |
2008年 | 1290篇 |
2007年 | 1359篇 |
2006年 | 1168篇 |
2005年 | 1102篇 |
2004年 | 989篇 |
2003年 | 910篇 |
2002年 | 823篇 |
2001年 | 724篇 |
2000年 | 683篇 |
1999年 | 598篇 |
1998年 | 248篇 |
1997年 | 179篇 |
1996年 | 144篇 |
1995年 | 136篇 |
1994年 | 114篇 |
1993年 | 130篇 |
1992年 | 356篇 |
1991年 | 390篇 |
1990年 | 343篇 |
1989年 | 358篇 |
1988年 | 308篇 |
1987年 | 277篇 |
1986年 | 268篇 |
1985年 | 279篇 |
1984年 | 219篇 |
1983年 | 181篇 |
1979年 | 241篇 |
1978年 | 158篇 |
1977年 | 148篇 |
1976年 | 135篇 |
1975年 | 163篇 |
1974年 | 154篇 |
1973年 | 176篇 |
1972年 | 138篇 |
1971年 | 122篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
991.
Cecilia Sgadari AnneL. Angiolillo BarryW. Cherney SandraE. Pike JoshuaM. Farber LeonidasG. Koniaris Padmavathy Vanguri ParrisR. Burd Nasreen Sheikh Ghanshyam Gupta Julie Teruya-Feldstein Giovanna Tosato 《Proceedings of the National Academy of Sciences of the United States of America》1996,93(24):13791-13796
Human Burkitt lymphoma cell lines give rise to progressively growing subcutaneous tumors in athymic mice. These tumors are induced to regress by inoculation of Epstein–Barr virus-immortalized normal human lymphocytes. In the present study, analysis of profiles of murine cytokine/chemokine gene expression in Burkitt tumor tissues excised from the nude mice showed that expression of the murine α-chemokine interferon-inducible protein-10 (IP-10) was higher in the regressing than in the progressive Burkitt tumors. We tested the effects of IP-10 on Burkitt tumor growth in nude mice. Inoculation of established Burkitt tumors either with crude preparations of murine IP-10 or with purified human IP-10 caused visible tumor necrosis in a proportion of the animals, although no complete tumor regressions were observed. Constitutive expression of murine IP-10 in Burkitt cells reduced their ability to grow as subcutaneous tumors, and caused visible tumor necrosis in a proportion of the animals. Histologically, IP-10-treated and IP-10-expressing Burkitt tumors had widespread evidence of tumor tissue necrosis and of capillary damage, including intimal thickening and vascular thrombosis. Thus, IP-10 is an antitumor agent that promotes damage in established tumor vasculature and causes tissue necrosis in human Burkitt lymphomas established subcutaneously in athymic mice. 相似文献
992.
Kumar Sridhar David Fischman Sheldon Goldberg Andrew Zalewski Paul Walinsky Doranne Porter Sarah Fenton Bhavdeep Gupta Randal Rake Sharon Gebhardt Michael Savage 《Catheterization and cardiovascular interventions》1996,39(3):224-229
Peripheral vascular complications are a significant source of morbidity after coronary artery stent implantation. The goal of this study was to assess the incidence, risk factors, and management of vascular complications after stent placement. The study population consisted of 101 consecutive patients who underwent stent placement for either elective or bailout indications. All patients received a standardized anticoagulation regimen of aspirin, dipyridamole, low molecular weight dextran, heparin, and warfarin. Peripheral vascular access sites were examined daily until hospital discharge. Vascular complications occurred in 16 of 101 (16%) patients, including femoral artery pseudoaneurysm (n = 11), hematoma requiring transfusion or surgery (n = 4), and arterlovenous fistula (n = 1). Intervention was required in 14 of 16 (88%) patients with complications. These included transfusion (n = 7), ultrasound-guided compression (n = 8), and/or vascular surgery (n = 7). Length of hospital stay was prolonged in patients with complications (14 ± 9 vs. 8 ± 5 d, P < 0.001). The development of peripheral vascular complications did not correlate with clinical or procedural variables such as age, cardiovascular risk factors, arterial sheath size, or elective vs. bailout indication. After the introduction of a pneumatic vascular compression device (FemoStop, C.A. Bard, Billerica, MA), a significant reduction In vascular complications was observed. Complications occurred in only 1 of 41 (2.4%) patients in whom the compression device was used in contrast to 13 of 58 (22.4%) patients compressed manually (P < 0.01). Thus peripheral vascular complications are frequent after coronary artery stent placement and are associated with serious morbidity and prolongation of hospital stay. These complications are significantly reduced by the use of a pneumatic vascular compression device despite intensive systemic anticoagulation. © 1996 Wiley-Liss, Inc. 相似文献
993.
Differentiation of pancreatic epithelial progenitor cells into hepatocytes following transplantation into rat liver 下载免费PDF全文
Mariana D. Dabeva Seong-Gyu Hwang Srinivasa Rao G. Vasa Ethel Hurston Phyllis M. Novikoff Douglas C. Hixson Sanjeev Gupta David A. Shafritz 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(14):7356-7361
The ability to identify, isolate, and transplant progenitor cells from solid tissues would greatly facilitate the treatment of diseases currently requiring whole organ transplantation. In this study, cell fractions enriched in candidate epithelial progenitor cells from the rat pancreas were isolated and transplanted into the liver of an inbred strain of Fischer rats. Using a dipeptidyl dipeptidase IV genetic marker system to follow the fate of transplanted cells in conjunction with albumin gene expression, we provide conclusive evidence that, after transplantation to the liver, epithelial progenitor cells from the pancreas differentiate into hepatocytes, express liver-specific proteins, and become fully integrated into the liver parenchymal structure. These studies demonstrate the presence of multipotent progenitor cells in the adult pancreas and establish a role for the liver microenvironment in the terminal differentiation of epithelial cells of foregut origin. They further suggest that such progenitor cells might be useful in studies of organ repopulation following acute or chronic liver injury. 相似文献
994.
995.
Bal Kishan Gupta Kailash Chandra Nayak Sunil Kumar Surendra Kumar Anjli Gupta Parul Prakash 《急性病杂志》2012,1(2):100-106
ObjectiveTo report a comparative clinical and histopathological study on oliguric and non-oliguric acute renal failure (ARF) in malaria.Method311 consecutive cases of malaria out of which 74 (23.79%) had ARF as per WHO criteria were conducted. Mean age was 32.58 (range 15–60 years) and male: female was 2:1.ResultMost of the cases developed ARF within 10 d of onset. 18 cases (11 falciparum, 2 mixed, 5 vivax) presented with oliguric and 56 (41 falciparum, 6 mixed, 9 vivax) with non-oliguric renal failure. Associated major manifestations were jaundice (75.68%), cerebral malaria (41.89%), bleeding manifestations (32.43%), severe anemia (27.03%), hypotension (25.68%), multi-organ failure (18.92%), severe thrombocytopenia (12.16%), and ARDS (8.11%). Kidney biopsy (n=20) showed acute tubular necrosis (n=7), Mesangioproliferative glomerulonephritis (n=4) or both (n=9). Hemodialysis was done in 8 cases of oliguric renal failure out of which 4 survived (average no. of session 2.9).ConclusionMost of the cases recovered within 3 weeks. Total mortality was 28.38% (n=21) and mortality was more in oliguric renal failure (72.22%) as compare to non-oliguric renal failure (14.29%). 相似文献
996.
D S Singh P R Gupta S S Gupta P K Bhatia P N Somani I S Gambhir A K Khare 《The Journal of tropical medicine and hygiene》1989,92(4):243-248
Three cases of acute viral hepatitis are reported with various cardiac changes such as transient left ventricular hypertrophy, myocarditis and progressive cardiomegaly (cardiomyopathy). Extra-hepatic manifestations of acute viral hepatitis are rare but have been well documented. The aims of the present study are to highlight the cardiac involvement in acute viral hepatitis and to report the clinical implications of cardiac changes in acute viral hepatitis. 相似文献
997.
The beta2 subunit inhibits stimulation of the alpha1/beta1 form of soluble guanylyl cyclase by nitric oxide. Potential relevance to regulation of blood pressure. 总被引:1,自引:0,他引:1 下载免费PDF全文
Cytosolic guanylyl cyclases (GTP pyrophosphate-lyase [cyclizing; EC 4.6.1.2]), primary receptors for nitric oxide (NO) generated by NO synthases, are obligate heterodimers consisting of an alpha and a beta subunit. The alpha1/beta1 form of guanylyl cyclase has the greatest activity and is considered the universal form. An isomer of the beta1 subunit, i.e., beta2, has been detected in the liver and kidney, however, its role is not known. In this study, we investigated the function of beta2. Immunoprecipitation experiments showed that the beta2 subunit forms a heterodimer with the alpha1 subunit. NO-stimulated cGMP formation in COS 7 cells cotransfected with the alpha1 and beta2 subunits was approximately 1/3 of that when alpha1 and beta1 subunits were cotransfected. The beta2 subunit inhibited NO-stimulated activity of the alpha1/beta1 form of guanylyl cyclase and NO-stimulated cGMP formation in cultured smooth muscle cells. Our results provide the first evidence that the beta2 subunit can regulate NO sensitivity of the alpha1/beta1 form of guanylyl cyclase. Northern analysis for guanylyl cyclase subunits was performed on RNA from kidneys of Dahl salt-sensitive rats, which have been shown to have decreased renal sensitivity to NO. Compared to the Dahl salt-resistant rat, message for beta2 was increased, beta1 was decreased, and alpha1 was unchanged. These results suggest a molecular basis for decreased renal guanylyl cyclase activity, i.e. , an increase in the alpha1/beta2 heterodimer, and decrease in the alpha1/beta1 heterodimer. 相似文献
998.
999.
Mehnoosh Torkzaban Priscilla Machado Ipshita Gupta Yang Hai Flemming Forsberg 《Ultrasound in medicine & biology》2021,47(1):3-18
Non-surgical treatment options for uterine fibroids are uterine artery embolization (UAE), high-intensity focused ultrasound ablation (HIFUA), and percutaneous microwave ablation (PMWA). Magnetic resonance imaging (MRI) is the reference standard imaging method before and after these procedures. Contrast-enhanced ultrasound (CEUS) has been studied as an alternative to MRI for evaluating the fibroids’ characteristics and responses to non-surgical treatments. PubMed, Ovid MEDLINE and Scopus databases were searched for literature published from January 2000 through June 7, 2020, that investigated the application of CEUS as an adjunct to monitor UAE, HIFUA or PMWA in human uterine fibroid treatments. Two independent reviewers analyzed 128 publications, out of which 17 were included. Based on this systematic review, CEUS provides detailed data about fibroid volume and vascularization prior, during and post UAE, and it helps determine the endpoint of the procedure. HIFUA with intra-procedural CEUS has faster volume shrinkage over a shorter time period with less needed energy and provides early detection of residual tissue after HIFUA. CEUS and contrast-enhanced MRI have sufficient agreement to be used interchangeably in the clinic to evaluate the therapeutic effect of PMWA and HIFUA on fibroids. 相似文献
1000.
Michael S. Kiernan Susanna R. Stevens W.H. Wilson Tang Javed Butler Kevin J. Anstrom Edo Y. Birati Justin L. Grodin Divya Gupta Kenneth B. Margulies Shane LaRue Victor G. Dávila-Román Adrian F. Hernandez Lisa de las Fuentes 《Journal of cardiac failure》2018,24(7):428-438