全文获取类型
收费全文 | 4525篇 |
免费 | 318篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 155篇 |
妇产科学 | 111篇 |
基础医学 | 593篇 |
口腔科学 | 134篇 |
临床医学 | 392篇 |
内科学 | 1017篇 |
皮肤病学 | 54篇 |
神经病学 | 436篇 |
特种医学 | 96篇 |
外国民族医学 | 1篇 |
外科学 | 496篇 |
综合类 | 28篇 |
一般理论 | 2篇 |
预防医学 | 414篇 |
眼科学 | 64篇 |
药学 | 437篇 |
中国医学 | 8篇 |
肿瘤学 | 365篇 |
出版年
2023年 | 28篇 |
2022年 | 84篇 |
2021年 | 121篇 |
2020年 | 99篇 |
2019年 | 140篇 |
2018年 | 131篇 |
2017年 | 99篇 |
2016年 | 128篇 |
2015年 | 124篇 |
2014年 | 174篇 |
2013年 | 233篇 |
2012年 | 332篇 |
2011年 | 313篇 |
2010年 | 168篇 |
2009年 | 185篇 |
2008年 | 292篇 |
2007年 | 274篇 |
2006年 | 244篇 |
2005年 | 244篇 |
2004年 | 232篇 |
2003年 | 178篇 |
2002年 | 178篇 |
2001年 | 80篇 |
2000年 | 66篇 |
1999年 | 72篇 |
1998年 | 47篇 |
1997年 | 34篇 |
1996年 | 21篇 |
1995年 | 19篇 |
1994年 | 29篇 |
1993年 | 27篇 |
1992年 | 40篇 |
1991年 | 38篇 |
1990年 | 38篇 |
1989年 | 34篇 |
1988年 | 24篇 |
1987年 | 23篇 |
1986年 | 15篇 |
1985年 | 22篇 |
1984年 | 21篇 |
1982年 | 11篇 |
1981年 | 16篇 |
1979年 | 20篇 |
1978年 | 10篇 |
1976年 | 13篇 |
1975年 | 11篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1972年 | 11篇 |
1969年 | 9篇 |
排序方式: 共有4863条查询结果,搜索用时 15 毫秒
51.
Essential hypertension and congestive heart failure (CHF) are examples of cardiovascular disorders that may cause renal failure, although sometimes a primary kidney defect may lead to hypertension. Renal damage in malignant and severe hypertension is dramatic, extensive, and rapidly progressive, although nephrosclerotic damage, which develops slowly and appears late in hypertension, is a rare cause of morbidity because mild to moderate hypertension is now the most common form. However, the incidence of end-stage renal failure associated with hypertension is markedly increasing, perhaps because of underdiagnosis of renal damage in hypertension, insufficient lowering of blood pressure in clinical practice, or inability of antihypertensive drugs to lower blood pressure sufficiently to preserve the kidney, a goal that may need specific drugs that act, for example, on the renin-angiotensin system (RAS). Renal vasoconstriction and reduction of renal blood flow are early companions of cardiac insufficiency and may be involved in the development of sodium and water retention. Profound reduction of cardiac output and arterial hypotension in severe CHF may lead to acute renal failure. Chronic renal insufficiency is associated with elevated cardiovascular morbidity and mortality. Renal impairment is often caused by a disease process, such as diabetes mellitus, that involves both the cardiovascular system and the kidney. When the primary disease is renal, possible reasons for an association include renal-dependent increase in blood pressure, activation of the RAS, overproduction of other vasoactive substances of renal origin, and electrolyte imbalances leading to fatal arrhythmias. 相似文献
52.
Gangwar Sanjeev Jois Seetharama D. S. Siahaan Teruna J. Vander Velde David G. Stella Valentine J. Borchardt Ronald T. 《Pharmaceutical research》1996,13(11):1657-1662
Purpose. To determine the different conformations of the acyloxyalkoxy-linked cyclic prodrug 1 of the model hexapeptide 2 in solution and to investigate the relationship between these solution conformations and the cellular permeability characteristics of this prodrug.
Methods. Two-dimensional Homonuclear Hartmann-Hahn spectroscopy, Rotating-Frame Overhouser effect spectroscopy, circular dichroism and molecular dynamics simulations were used to find the solution conformers of cyclic prodrug 1.
Results. Our spectroscopic findings suggest that cyclic prodrug 1 exhibits a major and a minor conformer in solution. The major conformer appears to have a well-defined secondary structure, which involves a -turn and 4 1 intramolecular hydrogen bond, creating a compact structure with a reduced average hydrodynamic radius compared to the model hexapeptide 2.
Conclusions. The increased ability of cyclic prodrug 1 to permeate membranes compared to the model hexapeptide 2 could be due to reduction in the average hydrodynamic radius of the molecule facilitating paracellular flux and/or the reduction in the hydrogen bonding potential facilitating transcellular flux. 相似文献
53.
M W Caldironi P Boccato C S Maifredini S Blandamura A di Summa G Costantin A G Rebuffi G C Zotti 《Tumori》1991,77(1):65-69
From May 1988 to June 1990, 260 patients with abdominal focal disease underwent ultrasonically guided percutaneous fine needle biopsy. The technique of so-called "FNAB-CYT" is described. The procedure entailed very few complications: the mortality rate was 0% and the morbidity rate was 1.5%. The specificity of the technique was 100%, and sensitivity was 93.43%. False-negative diagnoses were made in 8 cases, and in 5 patients the cytologic diagnoses were uncertain. There were no false-positives. The possibility of an immediate control of the collected material by the pathologist avoids the risk of inadequate samples and reduces the number of biopsies for the patient. Comparison among diagnoses on rapid and definitive preparations and histologic ones was carried out to evaluate the diagnostic efficiency of the cytologic procedure. In our experience, a rapid staining of the smears allowed a correct cytologic diagnosis in 87.7% of the cases within approximately 5 min of the biopsy. On the basis of our experience, the authors recommend FNAB-CYT as a routine first-level (less invasive) procedure for diagnosis of abdominal focal disease. 相似文献
54.
M Stella P De Nardi G Paganelli I Sassi M Zito P Magnani D Baratti F Mangili W Spagnolo A G Siccardi 《Acta chirurgica》1991,157(8):485-488
Radioactive antibodies that react with tumour-associated antigens to "tag" antigen-positive tumour cell deposits were given to 20 patients with primary or recurrent colorectal cancer. The tumour associated antigen TAG 72-specific monoclonal antibody B72.3 labelled with 125-Iodine was used, and the radioactivity in the tumour was sought during operation with a hand-held gamma detecting probe. Tumour was detected by the probe in 7 of 15 patients with primary cancer, with a mean tumour: normal tissue ratio of 3.9, and in 4 of 5 patients with recurrent disease, with a mean tumour: normal tissue ratio of 2.0. Immunohistochemical analysis of surgical specimens confirmed the results of the intraoperative detection. The incidence of TAG 72-positive tumours (11/20, 55%), detected by immunohistochemistry, was lower than the 80% in the other series, possibly because of sampling errors or because the cases studied were uncomplicated with small primary tumours. Results obtained with the probe were instrumental in modifying the operation in two of the four "positive" patients with recurrences, allowing the removal of tumour masses that would otherwise have been overlooked. 相似文献
55.
This article reports on a retrospective study of 59 joint placements of siblings in foster homes, involving a total of 137 children. An overall picture is presented of the agencies' considerations in making these placements. The number of prematurely terminated placements in this group amounted to 14 (23.7%). Several factors that appear related to premature termination are discussed.Frits Boer is a university lecturer in the Department of Child and Youth Psychiatry at the University of Leiden in the Netherlands and works as a child psychiatrist at the Academic Center for Child and Adolescent Psychiatry Curium in Oegstgeest. Stella Spiering is developmental psychologist in Rijswijk, the Netherlands. 相似文献
56.
Sui Wang Dylan P Hartley Suzanne L Ciccotto Stella H Vincent Ronald B Franklin Mi-Sook Kim 《Drug metabolism and disposition》2003,31(6):773-775
The purpose of the present study was to evaluate the effect of 1,7-phenanthroline (PH), which has been proposed to be a selective phase II enzyme inducer, on the gene expression of xenobiotic transporters, as well as hepatic and renal drug-metabolizing enzymes. After oral administration of PH for 3 days to male Sprague-Dawley rats, mRNA levels in liver (75 and 150 mg/kg doses) and kidney (75 mg/kg dose only) were determined using real-time quantitative polymerase chain reaction. At 150 mg/kg/day, PH treatment resulted in significant increases in hepatic mRNA levels of Mrp3 (36-fold), UGT1A6 (20-fold), UGT2B1 (4-fold), and quinone reductase (QR, 5-fold), compared with the vehicle-treated group. Similar increases in Mrp3 (99-fold), UGT1A6 (17-fold), UGT2B1 (3-fold), and QR (11-fold) mRNA levels were observed in the liver after PH treatment of rats at 75 mg/kg/day. In contrast, the expression levels of CYP2C11 and Oatp2 were decreased by approximately 80 and 50%, respectively. In addition, PH (75 mg/kg/day) elicited statistically significant changes in renal gene expression of CYP3A1, UGT1A6, QR, and Mrp3, but the magnitude of renal Mrp3 induction was less than 2-fold over control. Although PH is known to modulate hepatic glucuronidation in vivo, these data indicated that PH induced mRNA levels of the efflux transporter, Mrp3, which may also affect the disposition of xenobiotics. 相似文献
57.
Stella Chang Stacey R Long Lucie Kutikova Lee Bowman Denise Finley William H Crown Charles L Bennett 《Journal of clinical oncology》2004,22(17):3524-3530
PURPOSE: Cancer accounts for 60.9 billion dollars in direct medical costs and 15.5 billion dollars for indirect morbidity costs. These estimates are derived primarily from national surveys or Federal databases. We derive estimates of the costs of cancer using administrative databases, which include claims and employment-related information on individuals insured by private or Medicare supplemental health plans. METHODS: A retrospective matched-cohort control analysis was performed using 1998 to 2000 databases with information on insurance claims, benefits, and health productivity for 3 million privately insured employees, their dependents, and early retirees. Study patients had new diagnoses of one of seven types of cancer (n = 12,709). Controls without cancer were matched at a 3:1 ratio by demographics. A variable follow-up length was used (maximum of 2 years). Direct costs included health care costs for patients and deductibles and copayments for caregivers. Indirect costs of work absence and short-term disability (STD) were calculated for a subgroup of cancer patients and caregivers. RESULTS: Mean monthly health care costs ranged from 2,187 dollars for prostate cancer to 7,616 dollars for pancreatic cancer, most often driven by hospitalization. Costs for controls were 329 dollars per month. Indirect morbidity costs to employees with cancer averaged 945 dollars, a result of a mean monthly loss of 2.0 workdays and 5.0 STD days. CONCLUSION: The economic burden of cancer is substantial. It is feasible to derive tumor-specific estimates of direct and indirect costs for large numbers of cancer patients using administrative databases. Policy makers charged with providing annual cost-of-cancer estimates should incorporate data obtained from a broad range of sources. 相似文献
58.
Real-time quantification of CK-19 mRNA-positive cells in peripheral blood of breast cancer patients using the lightcycler system. 总被引:10,自引:0,他引:10
59.
Stella M Yu Rebecca M Nyman Michael D Kogan Zhihuan J Huang Renee H Schwalberg 《Ambulatory Pediatrics》2004,4(2):181-187
OBJECTIVE: To examine the association between the parent's language of interview and the access to care for children with special health care needs (CSHCN). METHODS: We used the 2001 National Survey of Children with Special Health Care Needs to compare socio-demographic characteristics and health care access variables among CSHCN with parents who interviewed in English and another language. Additional multivariate analyses explored the effect of language of interview on access to health care for the subgroup of Hispanic respondents. RESULTS: CSHCN with non-English-speaking parents were from less-educated and lower-income families and were more likely to lack insurance and have conditions that greatly affected their activities. These children were also more likely to have inadequate insurance (odds ratio [OR]=11.29), have an unmet need for family support services (OR=1.88), lack a personal doctor or nurse (OR=1.98), lack a usual source of care (OR=1.89), and lack family-centered care (OR=1.74). Non-English-speaking parents were more likely to report having employment consequences (OR=1.94) and spending over $500 out-of-pocket annually on the child's health care needs (OR=1.49). The likelihood of Hispanic children experiencing health care access barriers compared with non-Hispanic children was reduced when language was controlled for and several disparities between Hispanic children and other children became insignificant. CONCLUSIONS: CSHCN with non-English-speaking parents were more likely to be from disadvantaged families and to experience barriers to access than were CSHCN with English-speaking parents. Systems of care for CSHCN should consider the needs and challenges experienced by families whose primary language is not English. 相似文献
60.
Stella Regina Zamuner Juliana Pavan Zuliani Cristina Maria Fernandes José Maria Gutiérrez Catarina de Fátima Pereira Teixeira 《Toxicon》2005,46(7):806-813
Bothrops asper venom (BaV) causes systemic and local effects characterized by an acute inflammatory reaction with accumulation of leukocytes and release of endogenous mediators. In this study, the effects of BaV on the release of the cytokines IL-1, IL-6 and TNF-alpha and the eicosanoids LTB4 and TXA2 in the peritoneal cavity of mice were analyzed. We also investigated the participation of beta2 integrin chain, l-selectin, LFA-1, ICAM-1 and PECAM-1 adhesion molecules in the BaV-induced leukocyte accumulation. Levels of proinflammatory cytokines IL-6 and TNF-alpha, as well as eicosanoids LTB4 and TXA2 were significantly increased after BaV injection (250 microg/kg), whereas no increment in IL-1 was observed. Anti-mouse l-selectin, LFA-1, ICAM-1, PECAM-1 and beta2 integrin chain monoclonal antibodies resulted in a reduction of neutrophil accumulation induced by BaV injection compared with isotype-matched control injected animals. These data suggest that BaV is able to induce the activation of leukocytes and endothelium to express adhesion molecules involved in the recruitment of neutrophils into the inflammed site. Furthermore, these results showed that BaV induces the release of cytokines and eicosanoids in the local of the venom injection; these inflammatory mediators may be important for the initiation and amplification of the inflammatory reaction characteristic from Bothrops sp envenomation. 相似文献