全文获取类型
收费全文 | 49743篇 |
免费 | 3065篇 |
国内免费 | 229篇 |
专业分类
耳鼻咽喉 | 578篇 |
儿科学 | 1367篇 |
妇产科学 | 976篇 |
基础医学 | 6228篇 |
口腔科学 | 908篇 |
临床医学 | 4844篇 |
内科学 | 11450篇 |
皮肤病学 | 777篇 |
神经病学 | 4794篇 |
特种医学 | 1739篇 |
外国民族医学 | 1篇 |
外科学 | 7687篇 |
综合类 | 303篇 |
一般理论 | 34篇 |
预防医学 | 3253篇 |
眼科学 | 763篇 |
药学 | 2979篇 |
中国医学 | 70篇 |
肿瘤学 | 4286篇 |
出版年
2024年 | 33篇 |
2023年 | 334篇 |
2022年 | 537篇 |
2021年 | 1392篇 |
2020年 | 847篇 |
2019年 | 1311篇 |
2018年 | 1559篇 |
2017年 | 1124篇 |
2016年 | 1142篇 |
2015年 | 1385篇 |
2014年 | 1971篇 |
2013年 | 2619篇 |
2012年 | 3912篇 |
2011年 | 4038篇 |
2010年 | 2326篇 |
2009年 | 2156篇 |
2008年 | 3461篇 |
2007年 | 3606篇 |
2006年 | 3384篇 |
2005年 | 3214篇 |
2004年 | 2956篇 |
2003年 | 2762篇 |
2002年 | 2411篇 |
2001年 | 344篇 |
2000年 | 231篇 |
1999年 | 331篇 |
1998年 | 502篇 |
1997年 | 405篇 |
1996年 | 307篇 |
1995年 | 287篇 |
1994年 | 235篇 |
1993年 | 234篇 |
1992年 | 144篇 |
1991年 | 149篇 |
1990年 | 108篇 |
1989年 | 100篇 |
1988年 | 82篇 |
1987年 | 79篇 |
1986年 | 76篇 |
1985年 | 94篇 |
1984年 | 110篇 |
1983年 | 106篇 |
1982年 | 101篇 |
1981年 | 90篇 |
1980年 | 81篇 |
1979年 | 48篇 |
1978年 | 47篇 |
1977年 | 35篇 |
1976年 | 26篇 |
1975年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
Marc D. Feldman Joel Michalek 《Catheterization and cardiovascular interventions》2019,93(6):1057-1058
- True lumen crossing is superior to subintimal crossing.
- Subintimal versus true lumen crossing may only be apparent if IVUS is performed.
- Newer techniques for true lumen crossing need to be developed.
992.
National Prevalence of Lifestyle Counseling or Referral Among African-Americans and Whites with Diabetes 下载免费PDF全文
Background Modifiable risk factors such as diet and physical activity contribute to racial disparities among patients with diabetes.
Despite this, little is known about how frequently physicians provide counseling or referral to address these risk factors,
or whether such rates differ by patient race.
Methods We analyzed cross-sectional data from the 2002–2004 National Ambulatory Medical Care Survey and the National Hospital Ambulatory
Medical Care Survey. We used logistic regression to investigate the relationship between counseling/referral for nutrition
or exercise and patient factors, provider factors, and geographic location, with a focus on whether counseling rates were
independently associated with patient race.
Results Overall, counseling/referral for nutrition occurred in 36% of patient visits and counseling/referral for exercise occurred
in 18% of patient visits. After adjusting for patient, physician, and practice characteristics, there was no statistically
significant association between race and counseling/referral for nutrition (odds ratio for African-Americans compared to whites
[OR] 1.00, 95% confidence intervals [CI] 0.71–1.41) or for exercise (OR 0.74, CI 0.49–1.11). Significant predictors of counseling/referral
for both lifestyle interventions included younger patient age, private insurance, and treatment by a primary care provider.
Conclusions Rates of lifestyle modification counseling/referral were similarly low among African-Americans and whites in this national
study. Our results highlight a need for interventions to enhance physician counseling for patients with diabetes, particularly
those at high-risk for diabetes-associated morbidity and mortality, such as racial/ethnic minorities. 相似文献
993.
Habib G Caus T Avierinos JF Richard D Garcia M Biou F Maximovitch-Rodaminoff A Ambrosi P Luccioni R 《Echocardiography (Mount Kisco, N.Y.)》1998,15(7):665-668
A 69-year-old woman presented with chest pain and electrocardiographic evidence of subacute anterior ischaemia. Transthoracic and transesophageal echocardiography allowed correct diagnosis of a posttraumatic pseudoaneurysm of the left sinus of Valsalva. The large pseudoaneurysm caused compression of the left main coronary artery and was successfully treated by aortic root replacement, left main coronary artery ligation, and arterial bypass. 相似文献
994.
Blondon H Polivka M Joly F Flourie B Mikol J Messing B 《Gastroentérologie clinique et biologique》2005,29(8-9):773-778
We report 3 new cases of Mitochondrial-Neuro-Gastro-Intestinal Encephalomyopathy (MNGIE) (or Pseudo-Obstruction-Leukoencephalopathy-Intestinal-Pseudoobstruction Syndrome [POLIP]), a rare disease that associates chronic intestinal pseudo-obstruction (CIPO) and neurological symptoms. A review of the 72 reported cases together with these 3 cases revealed that this condition was associated with (a) a specific cluster of neurological symptoms including leukoencephalopathy (96%), polyneuropathy (96%), ophthalmoplegia (91%) and hearing loss (55%); (b) a CIPO syndrome with the presence of small bowel diverticulae (53%); and (c) mitochondrial cytopathy in 36 of the 37 tested patients (2 of our 3 cases), and thymidine phosphorylase gene mutations in all the 37 tested patients (2 of our cases). The etiology of POLIP/MNGIE syndrome appears therefore to be due to a mitochondrial cytopathy secondary to thymidine phosphorylase gene mutation(s). In 3 cases, including 2 of our 3 patients, mitochondrial abnormalities were evidenced at the ultrastructural level in digestive smooth muscle demonstrating that the pathogenesis of gastrointestinal involvement was directly related to mitochondrial alterations in digestive smooth muscle cells. 相似文献
995.
996.
Allez M Lemann M Bonnet J Cattan P Jian R Modigliani R 《The American journal of gastroenterology》2002,97(4):947-953
OBJECTIVE: Prediction of the clinical course of Crohn's disease (CD) is difficult in the long term. Our aim was to determine whether the presence of severe endoscopic lesions (SELs) may predict a higher risk of colectomy and penetrating complications. METHODS: All patients at our institution with active ileocoIonic CD who had colonoscopies between 1990 and 1996 were included in the study. SELs were defined as extensive and deep ulcerations covering more than 10% of the mucosal area of at least one segment of the colon. RESULTS: Among the 102 patients included, 53 had SELs at index colonoscopy. During the follow-up (median = 52 months), 37 patients underwent colonic resection. Probabilities of colectomy at 1, 3, and 8 yr were 20%, 26%, and 42%. Risk of colectomy was independently affected by the presence of SELs at index colonoscopy (relative risk [RR] = 5.43, 95% CI = 2.64-11.18), a Crohn's Disease Activity Index level greater than 288 (RR = 2.21, 95% CI = 1.09-4.47), and the absence of immunosuppressive therapy during the follow-up (RR = 2.44, 95% CI = 1.20-5.00). Probabilities of colectomy were, respectively, 31% and 6% at 1 yr, 42% and 8% at 3 yr, and 62% and 18% at 8 yr in patients with and without SELs. We performed a second analysis excluding the 14 patients operated on within the 3 months after the index colonoscopy: presence of SELs remained the only significant factor predictive of colectomy (RR = 6.72, 95% CI = 2.26-20.03). All six patients with penetrating complications during the follow-up had SELs at index colonoscopy. CONCLUSIONS: Patients with CD exhibiting deep and extensive ulcerations at colonoscopy have a more aggressive clinical course with an increased rate of penetrating complications and surgery. 相似文献
997.
Although sigmoid colon diverticulitis is frequently seen, right colon and transverse colon diverticulitis remain rare forms of the disease. This case report examined the disease course of a 46-year-old female who first presented to our institution in 1990 with perforated right-sided diverticulitis. During the next 11 years, she developed sigmoid colon diverticulitis and then transverse colon diverticulitis. The right and sigmoid colon diverticulitis were treated with surgery and the transverse colon diverticulitis was managed conservatively. This is the first reported case of a single patient who had separate episodes of diverticulitis in the right, transverse, and sigmoid colon. The evaluation and management of this patient has mirrored a trend in the literature and clinical practice.Reprints are not available. 相似文献
998.
Hypogonadism, quadriceps weakness, and exercise intolerance in chronic obstructive pulmonary disease 总被引:3,自引:0,他引:3
Van Vliet M Spruit MA Verleden G Kasran A Van Herck E Pitta F Bouillon R Decramer M 《American journal of respiratory and critical care medicine》2005,172(9):1105-1111
RATIONALE: Circulating levels of testosterone and gonadotrophins of patients with chronic obstructive pulmonary disease (COPD) have never been compared with those of elderly men with normal pulmonary function. Moreover, the relationship of hypogonadism with quadriceps muscle weakness and exercise intolerance has been studied scarcely in men with COPD. OBJECTIVES: To compare circulating levels of hormones of the pituitary-gonadotrophic axis of men with COPD with those of age-matched control subjects. Moreover, to study the relationship of hypogonadism with quadriceps muscle force, 6-min walking distance, and systemic markers of inflammation in the patients. METHODS AND MEASUREMENTS: Circulating levels of follicle-stimulating hormone, luteinizing hormone, testosterone, and sex hormone-binding globulin were determined, and free testosterone was calculated in 78 patients (FEV1: 44 +/- 17% of the predicted values) and 21 control subjects. Moreover, quadriceps muscle force, 6-min walking distance, number of pack-yr, and systemic inflammation were determined. MAIN RESULTS: Follicle-stimulating hormone and luteinizing hormone were higher in the patients, whereas testosterone was lower (p < or = 0.05). The latter finding was also present in 48 non-steroid-using patients with normal blood gases. Low androgen status was significantly related to quadriceps muscle weakness (r = 0.48) and C-reactive protein (r = -0.39) in the patients, but not to exercise intolerance, the number of pack-yr, or increased circulating levels of interleukin 8 or soluble receptors of tumor necrosis factor alpha. CONCLUSIONS: In contrast to exercise intolerance, quadriceps muscle weakness is related to low circulating levels of testosterone in men with COPD. 相似文献
999.
Dentali F Gianni M Lussana F Squizzato A Cattaneo M Ageno W 《British journal of haematology》2008,143(2):284-287
Two nonsense polymorphisms of Z-dependent protease inhibitor (ZPI; Serpina10) have been identified. To assess the risk of venous thromboembolism (VTE) associated with W303x and R67X Serpina10 mutations, we performed a meta-analysis of studies comparing the prevalence of these two mutations in VTE patients and in controls Odds Ratios (ORs) and 95% confidence intervals (CIs) were calculated for each trial and pooled using a random-effects model. Five studies involving 5000 patients were included. R67X and W303X mutations of Serpina10 were not associated with increased VTE risk (OR 1.63; 95% CI 0.84, 3.16 and OR 1.21; 95% CI 0.29, 4.98 respectively). 相似文献
1000.
Molecular and physiologic actions of insulin related to production of nitric oxide in vascular endothelium 总被引:8,自引:0,他引:8
Insulin has important vascular actions that regulate blood flow, in addition to its classical actions to coordinate glucose
homeostasis. Insulin-stimulated production of nitric oxide in vascular endothelium results in capillary recruitment and vasodilation
that diverts and increases blood flow to skeletal muscle and consequently increases glucose disposal. Thus, vascular actions
of insulin may be essential for coupling hemodynamic and metabolic homeostasis. A complete biochemical signaling pathway linking
the insulin receptor to activation of endothelial nitric oxide synthase in vascular endothelium has recently been elucidated.
Moreover, the time course and dose response for capillary recruitment in response to physiologic concentrations of insulin
parallels that of insulinmediated glucose uptake in vivo. Taken together, these observations suggest a molecular mechanism
that may help to explain how insulin resistance contributes to cardiovascular components of the metabolic syndrome and vascular
complications of diabetes. 相似文献