全文获取类型
收费全文 | 3054篇 |
免费 | 154篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 162篇 |
儿科学 | 131篇 |
妇产科学 | 92篇 |
基础医学 | 337篇 |
口腔科学 | 94篇 |
临床医学 | 277篇 |
内科学 | 557篇 |
皮肤病学 | 29篇 |
神经病学 | 258篇 |
特种医学 | 171篇 |
外科学 | 543篇 |
综合类 | 40篇 |
一般理论 | 2篇 |
预防医学 | 247篇 |
眼科学 | 24篇 |
药学 | 121篇 |
中国医学 | 2篇 |
肿瘤学 | 142篇 |
出版年
2022年 | 17篇 |
2021年 | 32篇 |
2019年 | 27篇 |
2018年 | 49篇 |
2017年 | 39篇 |
2016年 | 45篇 |
2015年 | 63篇 |
2014年 | 70篇 |
2013年 | 82篇 |
2012年 | 134篇 |
2011年 | 130篇 |
2010年 | 86篇 |
2009年 | 119篇 |
2008年 | 168篇 |
2007年 | 185篇 |
2006年 | 148篇 |
2005年 | 166篇 |
2004年 | 128篇 |
2003年 | 107篇 |
2002年 | 108篇 |
2001年 | 120篇 |
2000年 | 112篇 |
1999年 | 106篇 |
1998年 | 42篇 |
1997年 | 54篇 |
1996年 | 38篇 |
1995年 | 39篇 |
1994年 | 38篇 |
1993年 | 20篇 |
1992年 | 69篇 |
1991年 | 55篇 |
1990年 | 49篇 |
1989年 | 47篇 |
1988年 | 43篇 |
1987年 | 36篇 |
1986年 | 36篇 |
1985年 | 31篇 |
1984年 | 27篇 |
1983年 | 26篇 |
1982年 | 23篇 |
1981年 | 26篇 |
1980年 | 21篇 |
1979年 | 40篇 |
1978年 | 30篇 |
1977年 | 16篇 |
1976年 | 18篇 |
1975年 | 16篇 |
1974年 | 22篇 |
1973年 | 13篇 |
1972年 | 20篇 |
排序方式: 共有3229条查询结果,搜索用时 15 毫秒
71.
72.
Despite a significant increase in the size of the Asian American elderly population, little is known about their social service needs and the level of service being provided them. This study used a survey methodology to examine all Asian American senior programs (N = 20) in a major American metropolitan region. The response rate was 90% with respondent agencies serving as the unit of analysis. Findings suggest that Asian elderly clients were primarily women and 'old-old', and that many of them were on SSI. Services provided were primarily tangible and facilitative, rather than clinical. Services needed but not provided were emergency psychiatric care, home attendants, home-delivered meals, legal services, medical services, and protective services. Findings of this study provide useful information for further research and program planning for Asian American elders in urban settings. 相似文献
73.
Hebart H Wuchter P Loeffler J Gscheidle B Hamprecht K Sinzger C Jahn G Dietz K Kanz L Einsele H 《Bone marrow transplantation》2001,28(2):213-218
Early diagnosis of CMV infection based on sensitive diagnostic assays has helped to reduce CMV-related mortality after allogeneic stem cell transplantation (SCT). In this study, the commercialized Murex CMV DNA Hybrid Capture assay (version 2.0) (HCS) was prospectively compared to an in-house CMV-DNA PCR assay from whole blood in patients after allogeneic stem cell transplantation. Overall, a high concordance between HCS and PCR was documented (kappa = 0.686; n = 385). The HCS assay was found to be as sensitive as the PCR indicating active CMV infection at a median of 35 and 34 days after transplantation, respectively. None of the HCS-negative patients developed CMV-related symptoms (negative predictive value 100%). Declining CMV DNA load in the blood was found to be an indicator for effective antiviral therapy, whereas persistence of a high viral load was associated with fatal CMV disease. In conclusion, the Hybrid Capture CMV DNA assay (v 2.0) allows early diagnosis of CMV infection after allogeneic SCT and assessment of the efficacy of antiviral therapy. 相似文献
74.
McMurray J Cohen-Solal A Dietz R Eichhorn E Erhardt L Hobbs FD Krum H Maggioni A McKelvie RS Piña IL Soler-Soler J Swedberg K 《European journal of heart failure》2005,7(5):710-721
Surveys of prescribing patterns in both hospitals and primary care have usually shown delays in translating the evidence from clinical trials of pharmacological agents into clinical practice, thereby denying patients with heart failure (HF) the benefits of drug treatments proven to improve well-being and prolong life. This may be due to unfamiliarity with the evidence-base for these therapies, the clinical guidelines recommending the use of these treatments or both, as well as concerns regarding adverse events. ACE inhibitors have long been the cornerstone of therapy for systolic HF irrespective of aetiology. Recent trials have now shown that treatment with beta-blockers, aldosterone antagonists and angiotensin receptor blockers also leads to substantial improvements in outcome. In order to accelerate the safe uptake of these treatments and to ensure that all eligible patients receive the most appropriate medications, a clear and concise set of clinical recommendations has been prepared by a group of clinicians with practical expertise in the management of HF. The objective of these recommendations is to provide practical guidance for non-specialists, in order to increase the use of evidenced based therapy for HF. These practical recommendations are meant to serve as a supplement to, rather than replacement of, existing HF guidelines. 相似文献
75.
Angiotensin II and endothelin may participate in increasing blood pressure and inducing end-organ damage, but the evidence is conflicting. We tested the hypothesis that endothelin(A) receptor blockade would ameliorate blood pressure and end-organ damage in a rat model of human renin-dependent hypertension. We studied rats that were transgenic for both the human renin and angiotensinogen genes. Experimental groups (n=12 each) of untreated transgenic rats, transgenic rats receiving subdepressor doses of losartan (10 mg/kg), transgenic rats receiving LU 135252 (30 mg/kg), transgenic rats receiving both drugs, and nontransgenic rats were studied between 6 to 10 weeks of age. Blood pressure was measured with tail-cuff sphygmomanometry. Gene expression for atrial natriuretic peptide, collagen III, and ACE was measured. The mortality rate in untreated transgenic rats was 42%, which is consistent with previous observations in this line. Single losartan or LU 135252 treatment reduced mortality incidence to 1 rat per group (8%), without significantly lowering blood pressure. In the combination group, blood pressure was normalized and all rats survived. The drug combination also decreased elevated water intake in transgenic rats to normal levels and significantly reduced cardiac hypertrophy. Furthermore, the combination of drugs decreased cardiac atrial natriuretic peptide, ACE gene, and renal collagen III gene expression. We suggest that endothelin participates in this model of angiotensin II-induced hypertension and end-organ damage. Our findings may have clinical implications and provide a rationale for combining angiotensin II type 1 receptor and endothelin(A) receptor blockade to obtain a synergistic effect. 相似文献
76.
PATHOGENESIS: Fabry disease is an inherited lysosomal storage disorder caused by deficiency of the enzyme alpha-galactosidase A. The enzyme deficiency results in accumulation of glycosphingolipids in the lysosomes n nearly all cell types and tissues leading to a multisystem disease. MANIFESTATIONS include painful crisis, angiokeratomas, corneal dystrophy, and hypohydrosis. The severe renal, cerebrovascular, and cardiac involvement is predominantly responsible for premature mortality in Fabry patients. The disease is X-linked and manifests primarily in hemizygous males but also heterozygous females can be affected. CARDIAC INVOLVEMENT is frequent in Fabry disease. Patients develop hypertrophic cardiomyopathy, arrhythmias, conduction abnormalities, and valvular abnormalities. Although Fabry disease leads to a complex clinical syndrome, there are studies indicating that manifestations can be limited to the heart. The isolated cardiac variant of Fabry disease seems to be more common than previously thought: around 3-6% of male patients with left ventricular hypertrophy seem to suffer from this disease variant. ENZYME REPLACEMENT THERAPY: Recent advances in molecular biology and genetic engineering have enabled the development of enzyme replacement therapy in Fabry disease. Results from two independent therapy studies are indeed promising: Infusion of the enzyme preparation seems to be well tolerated and effective in catabolizing the lipid deposits. This enzyme replacement therapy could be one of the first examples for causal treatment of left ventricular hypertrophy. Therefore, early diagnosis of hypertrophy patients with the cardiac variant of Fabry disease is important. 相似文献
77.
L B Seeff E C Wright H J Zimmerman H J Alter A A Dietz B F Felsher J D Finkelstein P Garcia-Pont J L Gerin H B Greenlee J Hamilton P V Holland P M Kaplan T Kiernan R S Koff C M Leevy V J McAuliffe N Nath R H Purcell E R Schiff C C Schwartz C H Tamburro Z Vlahcevic R Zemel D S Zimmon 《Annals of internal medicine》1978,88(3):285-293
Hepatitis B immune globulin (HBIG) and immune serum globulin (ISG) were examined in a randomized, double-blind trial to assess their relative efficacies in preventing type B hepatitis after needle-stick exposure to hepatitis B surface antigen (HBsAG)-positive donors. Clinical hepatitis developed in 1.4% of HBIG and in 5.9% of ISG recipients (P = 0.016), and seroconversion (anti-HBs) occurred in 5.6% and 20.7% of them respectively (P less than 0.001). Mild and transient side-effects were noted in 3.0% of ISG and in 3.2% of HBIG recipients. Available donor sera were examined for DNA polymerase (DNAP) and e antigen and antibody (HBeAg; anti-HBE). Both DNAP and HBeAg showed a highly statistically significant correlation with the infectivity of HBsAg-positive donors. Hepatitis B immune globulin remained significantly superior to ISG in preventing type B hepatitis even when the analysis was confined to these two high-risk subgroups. The efficacy of ISG in preventing type B hepatitis cannot be ascertained because a true placebo group was not included. 相似文献
78.
Reutershan J Ressel M Wagner T Schröder T Dietz K Fretschner R 《Journal of medical engineering & technology》2013,37(5):194-199
Primary objective : To evaluate a new technical approach to measuring effective pulmonary blood flow (PBF) in mechanically ventilated patients. Research design : Prospective clinical study; evaluation of accuracy and reproducibility. Methods : Effective pulmonary blood flow was determined non-invasively in 32 mechanically ventilated patients by using a new rebreathing system (PBF rb ). Cardiac output corrected for intrapulmonary shunt was taken as reference value (PBF thd ). Bias, precision and reproducibility of the rebreathing method were calculated from duplicate measurements in each patient. Main results : The mean difference between PBF rb and PBF thd was m v 0.67 v - v 0.83 l min m 1. The mean difference between duplicate measurements with the rebreathing system was 0.16 v - v 0.36 l min m 1. However, the accuracy of the rebreathing system tended to decrease in patients with PBF levels greater than 6 l min m 1. Conclusions : The new device appears to be reliable for determination of PBF values below 6 l min m 1. With this limitation, the present method may be used as a trend-indicator of PBF in mechanically ventilated patients. 相似文献
79.
Objective
To explore the effect of menopause and hormone replacement therapy on pelvic organ prolapse and pelvic floor muscle function.Methods
The records of patients who attended a tertiary urogynaecological center were reviewed retrospectively. A standardised interview included menopausal age, i.e. years since last period or onset of menopausal symptoms, current or previous hormone use. The clinical examination included prolapse assessment (POP-Q) and palpation of the levator ani muscle. 4D transperineal ultrasound, supine and after voiding, was performed in all patients. Volume data sets were analysed for pelvic organ descent and measures of contractility and distensibility of the pelvic floor at a later date, blinded to all clinical data.Results
Of 311 women seen during the inclusion period, 65% were postmenopausal. Current systemic or local hormone use was reported by 7% and 6%, respectively. 163 women (52%) reported prolapse symptoms with a mean bother of 5.7/10. Significant pelvic organ prolapse was found on clinical examination (POP-Q stage ≥ 2) in 77%, and diagnosed on ultrasound in 61%. On multivariate analysis, controlling for calendaric age, parity and levator avulsion, there was no evidence for menopausal age as an independent predictor of any symptom and sign of pelvic organ prolapse and pelvic floor muscle function. Local oestrogen use and past or present hormone replacement therapy had no detectable effect on any pelvic floor parameter.Conclusions
Hormone deficiency following menopause is unlikely to play a major role in pelvic organ support and levator ani function. Hence, both do not appear to be substantially influenced by local or systemic hormone replacement therapy. 相似文献80.
Delena Caagbay Friyan Turel Fatakia Hans Peter Dietz Camille Raynes-Greenow Natalia Martinho Kirsten I. Black 《Revista brasileira de fisioterapia (S?o Carlos (S?o Paulo, Brazil))》2021,25(2):214-220
BackgroundPelvic floor muscle function has been shown to be inversely associated with pelvic organ prolapse in Western women, however differences have been documented between ethnic groups.ObjectiveTo determine if pelvic floor muscle strength and thickness and hiatal area are associated with pelvic organ prolapse in Nepali women.MethodsThis cross-sectional study included non-pregnant Nepali women ≥18 years attending an outpatient gynecology clinic in Kathmandu, Nepal. A clinical examination included the pelvic organ prolapse quantification (POP-Q)- system examination and Modified Oxford Scale. Puborectalis muscle thickness and hiatal area were assessed using 3D/4D translabial ultrasound. Statistical analysis included Pearson's correlation and multiple regression (p < 0.05).ResultsOf the 123 women; 14 (11%) had POP-Q stage 0 prolapse, 29 (24%) stage I, 69 (56%) stage II, 8 (7%) stage III, and 3 (2%) stage IV. Mean ± SD Modified Oxford Scale was 3.37 ± 0.48 and muscle thickness was 1.14 ± 0.21 cm, hiatal area at rest was 14.67 ± 3.11 cm2 and on contraction was 11.29 ± 2.51 cm2. No associations were found between pelvic floor muscle strength or thickness and POP-Q stages 0–IV. There was a positive correlation found between hiatal area at rest and pelvic organ prolapse stage (r = 0.34, p < 0.001)and hiatal area on contraction and prolapse stage (r = 0.30, p < 0.001) and a negative correlation between pelvic floor muscle strength and hiatal area on contraction (r = ?0.36, p < 0.001).ConclusionIn contrast to previous findings, pelvic floor muscle strength and thickness are not associated with pelvic organ prolapse in this sample of Nepali women. It is important to consider these findings when developing pelvic organ prolapse treatment and management strategies in this population. 相似文献