全文获取类型
收费全文 | 1700篇 |
免费 | 124篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 42篇 |
妇产科学 | 27篇 |
基础医学 | 253篇 |
口腔科学 | 5篇 |
临床医学 | 169篇 |
内科学 | 378篇 |
皮肤病学 | 23篇 |
神经病学 | 173篇 |
特种医学 | 53篇 |
外科学 | 280篇 |
综合类 | 15篇 |
一般理论 | 1篇 |
预防医学 | 99篇 |
眼科学 | 56篇 |
药学 | 75篇 |
中国医学 | 2篇 |
肿瘤学 | 161篇 |
出版年
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 48篇 |
2020年 | 20篇 |
2019年 | 24篇 |
2018年 | 34篇 |
2017年 | 29篇 |
2016年 | 37篇 |
2015年 | 50篇 |
2014年 | 58篇 |
2013年 | 73篇 |
2012年 | 92篇 |
2011年 | 97篇 |
2010年 | 56篇 |
2009年 | 48篇 |
2008年 | 89篇 |
2007年 | 100篇 |
2006年 | 98篇 |
2005年 | 118篇 |
2004年 | 85篇 |
2003年 | 72篇 |
2002年 | 70篇 |
2001年 | 52篇 |
2000年 | 38篇 |
1999年 | 32篇 |
1998年 | 17篇 |
1997年 | 16篇 |
1996年 | 15篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 30篇 |
1991年 | 26篇 |
1990年 | 19篇 |
1989年 | 26篇 |
1988年 | 26篇 |
1987年 | 24篇 |
1986年 | 12篇 |
1985年 | 28篇 |
1984年 | 17篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1973年 | 6篇 |
1972年 | 4篇 |
排序方式: 共有1826条查询结果,搜索用时 15 毫秒
101.
Neuroprotective properties of estrogen have been established in animal models, but clinical trials of hormone replacement therapy (HRT) produced contradictory results. We examined the impact of HRT on age-related regional changes in human brain volume. Six brain regions were measured twice, five years apart, in 12 healthy women who took HRT and in matched controls who did not. The controls showed a typical pattern of differential brain shrinkage in the association cortices and the hippocampus with no change in the primary visual cortex. In contrast, women who took HRT showed comparable shrinkage of the hippocampus but no significant shrinkage of the neocortex. Future large scale studies may benefit from applying regional rather than global measures in assessment of brain integrity. 相似文献
102.
Weissman MM Gross R Fyer A Heiman GA Gameroff MJ Hodge SE Kaufman D Kaplan SA Wickramaratne PJ 《Archives of general psychiatry》2004,61(3):273-279
BACKGROUND: Evidence from a genetic linkage study had suggested a possible syndrome in some families with panic disorder (PD). This syndrome includes bladder problems (possibly urinary interstitial cystitis [IC]), thyroid disorders, chronic headaches/migraine, and/or mitral valve prolapse. In 19 multiplex families with PD, one marker (D13S779) on chromosome 13 gave a logarithm of odds score of more than 4 when individuals with any of the syndrome conditions were analyzed as affected. Families with the bladder problems yielded the highest logarithm of odds scores. These findings were replicated in an extended sample of 60 families. Whereas PD had been well characterized by direct interview, the urologic problems had been found only via medical history checklists and records. A case review by a board-certified urologist suggested they could be IC. OBJECTIVE: To determine whether patients diagnosed as having IC by urodynamics and/or cystoscopy and their first-degree relatives (FDRs) have increased rates of the syndrome conditions, thus validating that the bladder problems observed in the linkage study could be IC and providing further support for the panic syndrome. DESIGN: Case-control and family history study. SETTING: Two metropolitan urology clinics. PARTICIPANTS: One hundred forty-six probands (67 with IC and 79 with other urologic disorders) and 815 FDRs. MAIN OUTCOME MEASURES: Lifetime rates of syndrome conditions in probands and FDRs who were blind to urologic or psychiatric diagnoses in the proband. RESULTS: Compared with patients without IC, patients with IC had a significantly higher lifetime prevalence of PD (controlling for age and sex) (odds ratio, 4.05; 95% confidence interval, 1.22-13.40; P =.02) and a higher lifetime prevalence of any of the syndrome disorders (controlling for age and sex) (odds ratio, 2.22; 95% confidence interval, 0.89-5.54; P =.09). First-degree relatives of probands with (vs without) IC were significantly more likely to have PD, thyroid disorder, urologic problems, and any of the syndrome disorders (controlling for age and sex of the relative and sex of the proband) (adjusted odds ratio, 1.95; 95% confidence interval, 1.13-3.38; P =.02). These results in relatives were not influenced by PD in probands, and did not change substantially when controlling for the proband-relative relationship, modeling age as a categorical (vs continuous) variable, or excluding FDRs with PD. There were no interactions between proband IC status and sex of the relative. CONCLUSIONS: The increased frequency of seemingly disparate disorders in patients with IC and their FDRs is consistent with the genetic linkage findings in families with PD. These findings suggest that the bladder problems observed in the linkage study may be IC. The hypothesis that there is a familial, possibly pleiotropic, syndrome that may include IC, PD, thyroid disorders, and other disorders of possible autonomic or neuromuscular control deserves further investigation. 相似文献
103.
OBJECTIVES: To perform an updated meta-analysis of the effect of vitamin A supplementation on childhood morbidity from respiratory tract infections and diarrhea.Study design A comprehensive search of the 1966 to 2000 MEDLINE database and review of the reference lists of relevant articles identified 9 randomized controlled trials dealing with morbidity from respiratory infections and diarrhea in children 6 months to 7 years of age and provided "intention-to-treat" data. RESULTS: The combined results indicated that vitamin A supplementation has no consistent overall protective effect on the incidence of diarrhea (relative risk, 1.00; 95% CI, 0.94-1.07) and that it slightly increases the incidence of respiratory tract infections (relative risk, 1.08; 95% CI, 1.05-1.11). CONCLUSIONS: High-dose vitamin A supplements are not recommended on a routine basis for all preschool children and should be offered only to individuals or populations with vitamin A deficiency. 相似文献
104.
We report a case of Dubin-Johnson Syndrome in a neonate presenting with severe direct hyperbilirubinemia, which failed to respond to phenobarbital treatment. Ursodeoxycholic Acid added to therapy was well tolerated, and resulted in declining bilirubin concentration. We suggest ursodeoxycholic acid in treatment for Dubin-Johnson Syndrome with severe direct hyperbilirubinemia presenting in the neonatal age. 相似文献
105.
Allergen-specific immunotherapy, although efficacious, is now less frequently used because of potential adverse reactions. Recently, two new types of allergen immunotherapy have been developed that appear to overcome this problem, namely allergen gene vaccination and vaccination with allergen-immunstimulatory DNA conjugates. In animal models of allergy, both have been shown to induce nonallergic T-helper cell type 1 immune responses to allergens and downregulate pre-existing T-helper cell type 2 responses. In initial clinical trials with allergic patients, allergen-immunostimulatory DNA conjugates were well-tolerated, induced immunoglobulin-G but not immunoglobulin-E antibodies and appeared to have great potential as a novel, safe and efficacious type of allergen specific immunotherapy. 相似文献
106.
107.
INTRODUCTION: Osteoporosis is a major cause of morbidity in liver transplant recipients and is associated with multiple factors. OBJECTIVES: To evaluate bone mineral density (BMD), bone turnover and calcium-regulating hormones in 29 patients (17 men, 12 women) 2-12 yrs following liver transplantation for non-alcoholic liver diseases. RESULTS: Fifteen patients (52%) were on immunosuppressive treatment with tacrolimus and 14 (48%) with cyclosporine. Eleven patients (38%) were currently on prednisone, 18 patients (62%) had stopped glucocorticoid treatment 6 months to 11 yrs prior to the study. Nineteen patients (65.5%) had decreased BMD according to WHO criteria, 17 (58.2%) at the femoral neck, 13 (44.8%) at the lumbar spine. Nineteen patients (65.5%) had a subnormal (<15 ng/mL) serum level of 25 (OH) D3. These patients had significantly lower BMD at the femoral neck (p = 0.02). Femoral neck BMD negatively correlated with serum parathyroid hormone level (p = 0.06, r = -0.35), length of the post-transplantation period (p = 0.025, r = -0.416) and duration of glucocorticoid treatment (p = 0.029, r = -0.406), regardless of its cumulative dose. Symptomatic fractures were less frequent in tacrolimus treated patients than in cyclosporine users (p = 0.03). CONCLUSIONS: Decreased BMD is frequent following liver transplantation and is affected by vitamin D deficiency, cyclosporine use, and the duration of glucocorticoid therapy, but not by its cumulative dose. Achievement and maintenance of optimal vitamin D status and shortening of glucocorticoid treatment period may have a favorable effect on bone preservation. 相似文献
108.
Segal E Dvorkin L Lavy A Rozen GS Yaniv I Raz B Tamir A Ish-Shalom S 《Journal of the American College of Nutrition》2003,22(3):201-207
BACKGROUND: Lactose intolerance (LI) is a common enzymatic insufficiency, manifesting by poor tolerance of dairy products, leading to low calcium intake and poor calcium absorption from dairy products. These changes might lead to an impairment of bone metabolism [1]. OBJECTIVES: To evaluate the impact of LI on quantitative bone parameters in axial and appendicular skeletal sites. To assess the impact of calcium intake from dairy and non-dairy nutritional sources, calcium regulating hormones and bone turnover on quantitative bone parameters in LI patients. METHODS: We evaluated calcium intake and bone status in sixty-six patients with LI, 49 women and 17 men, aged 20 to 78. Bone mass was assessed at the lumbar spine (LS), total hip (TH) and femoral neck (FN) by dual-energy x-ray absorptiometry (DEXA) and at the radius, tibia, phalanx by quantitative ultrasound. Serum calcium, albumin, inorganic phosphate, calcium regulating hormones and markers of bone turnover were evaluated. RESULTS: Total daily calcium intake was below the recommended by the American Dietetic Association [2] in all study participants (mean 692 mg/day +/- 162). Elevated level of urinary deoxypyridinoline crosslinks (DPD) was observed in 63 (96%) patients and was negatively correlated with total daily calcium intake (r = -0.998, p = 0.025) and with nondairy calcium intake (r = -0.34, p = 0.015). Parathyroid hormone (PTH) level in the upper third of normal range (45-65 ng/L) was observed in 11 (17%) patients. Parathyroid hormone (PTH) was inversely correlated with total calcium intake (r = -0.4, p = 0.001), dairy calcium intake (r = -0.83, p = 0.05), non-dairy calcium intake (r = -0.29, p = 0.043), 25OHD(3) serum level (r = -0.3, p = 0.007) and positively correlated with bone turnover markers (deoxypyridinoline crosslinks [DPD], r = 0.36, p = 0.01 and bone specific alkaline phosphatase [BSAP] r = 0.36, p = 0.01). Decrease in quantitative bone parameters compared to age-matched controls was observed in the axial and in the appendicular skeleton in men and in postmenopausal women: mean z-score for LS -0.87 +/- 0.22 and -1.32 +/- 0.65, p = 0.004 and 0.015, tibia -1.15 +/- 0.53 and -0.44 +/- 0.044, p < 0.001 and 0.27, phalanx -0.98 +/- 0.22 and -0.52 +/- 0.98, p < 0.001. We observed decrease in bone mass in patients with serum PTH in the upper tertile of normal range in the FN (z-score -0.57 +/- 0.6 versus -0.03 +/- 0.9, p = 0.025), TH (-0.51 +/- 0.96 versus 0.04 +/- 0.9, p = 0.05) and radius (-1.84 +/- 0.27 versus -0.07 +/- 1.61, p = 0.025, respectively). z-scores in FN and TH positively correlated with serum 25OHD(3) level (r = 0.31, 0.29; p = 0.014, 0.019). In postmenopausal women serum 25OHD(3) level correlated also with LS z-scores (r = 0.52, p = 0.004); FN and TH z-scores negatively correlated with DPD level (r = -0.51, p = 0.02 and r = -0.55, p = 0.04). CONCLUSION: LI state may lead to increased bone turnover and decreased bone mass especially in men and postmenopausal women. Impaired vitamin D status and low calcium intake may be deleterious to bone in this condition. 相似文献
109.
Solitary fibrous tumors are rare fibrous tumors found in various anatomic sites. Extrathoracic neoplasms are often symptomatic at presentation, with paraneoplastic hypoglycemia being reported as one of the associated clinical features of such slow-growing tumors. As hypoglycemia can be an emergent clinical situation, we describe a patient with a giant abdominal tumor who presented with a symptomatic hypoglycemia, which might be regarded as a diagnostic clue. 相似文献
110.
Differential expression of galectin-3 in pituitary tumors 总被引:24,自引:0,他引:24
Riss D Jin L Qian X Bayliss J Scheithauer BW Young WF Vidal S Kovacs K Raz A Lloyd RV 《Cancer research》2003,63(9):2251-2255
Galectin-3 (Gal-3), a beta-galactoside-binding protein, has been implicated in a variety of biological functions, including cell proliferation and differentiation, tumor cell adhesion, angiogenesis, apoptosis, tumor progression, and metastasis. We investigated the role of Gal-3 in the development and progression of pituitary tumors. Immunohistochemical and Western blot analysis of normal and neoplastic human pituitaries showed that only lactotroph (PRL) and corticotroph (ACTH) hormone-producing cells and tumors expressed Gal-3. Gal-3 was present in 24 of 38 (63.2%) PRL adenomas, 5 of 6 (83.3%) PRL carcinomas, 19 of 41 (46.3) ACTH adenomas, and 7 of 8 (87.5%) ACTH carcinomas, but not in 112 other pituitary adenomas and carcinomas. Pituitary folliculo-stellate cells, which have macrophage-type functions in the anterior pituitary, also expressed Gal-3. Hyperplastic and neoplastic pituitaries from p27(Kip1) (p27)-null mice, which produce mainly ACTH, showed increased Gal-3 expression levels compared with control mice. Treatment with transforming growth factor beta1, which regulates pituitary cell proliferation, reduced Gal-3 as well as p27 expression levels in cultured HP75 pituitary cells and Gal-3 in cultured pituitary cells from p27-null mice, suggesting that p27 is not necessary for the inhibitory effects of transforming growth factor beta1 on the cell cycle in the pituitary. The role of Gal-3 in pituitary cell function was examined by RNA interference experiments. Inhibition of Gal-3 gene expression by RNA interference decreased HP75 cell proliferation and increased apoptosis. These results indicate that Gal-3 has an important role in pituitary cell proliferation and tumor progression. 相似文献