全文获取类型
收费全文 | 48921篇 |
免费 | 2587篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 685篇 |
儿科学 | 978篇 |
妇产科学 | 1083篇 |
基础医学 | 6279篇 |
口腔科学 | 2397篇 |
临床医学 | 3778篇 |
内科学 | 12468篇 |
皮肤病学 | 894篇 |
神经病学 | 4181篇 |
特种医学 | 925篇 |
外科学 | 6356篇 |
综合类 | 255篇 |
一般理论 | 17篇 |
预防医学 | 4143篇 |
眼科学 | 1046篇 |
药学 | 3328篇 |
中国医学 | 189篇 |
肿瘤学 | 2644篇 |
出版年
2024年 | 26篇 |
2023年 | 305篇 |
2022年 | 252篇 |
2021年 | 965篇 |
2020年 | 535篇 |
2019年 | 1078篇 |
2018年 | 1881篇 |
2017年 | 1190篇 |
2016年 | 1195篇 |
2015年 | 1489篇 |
2014年 | 1640篇 |
2013年 | 2363篇 |
2012年 | 4409篇 |
2011年 | 4504篇 |
2010年 | 2367篇 |
2009年 | 1732篇 |
2008年 | 3738篇 |
2007年 | 3827篇 |
2006年 | 3703篇 |
2005年 | 3528篇 |
2004年 | 3084篇 |
2003年 | 2833篇 |
2002年 | 2622篇 |
2001年 | 210篇 |
2000年 | 161篇 |
1999年 | 182篇 |
1998年 | 168篇 |
1997年 | 150篇 |
1996年 | 136篇 |
1995年 | 118篇 |
1994年 | 97篇 |
1993年 | 96篇 |
1992年 | 94篇 |
1991年 | 88篇 |
1990年 | 54篇 |
1989年 | 57篇 |
1988年 | 39篇 |
1987年 | 31篇 |
1986年 | 35篇 |
1985年 | 44篇 |
1984年 | 60篇 |
1983年 | 39篇 |
1982年 | 62篇 |
1981年 | 44篇 |
1980年 | 55篇 |
1978年 | 26篇 |
1977年 | 20篇 |
1976年 | 22篇 |
1975年 | 23篇 |
1974年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Herrerías JM Esteban JM Caballero-Plasencia AM Valenzuela-Barranco M Motilva V Alarcón C Martín J Herrerías JM Esteban P 《Digestive diseases and sciences》2003,48(5):986-991
Cyclic GMP plays an important role in maintaining homeostasis in the gastric mucosa. NSAIDs damage the mucosa by mechanisms that may be mediated by alterations in the intragastric concentration of cyclic GMP. To test this hypothesis we studied the effects of the oral administration of acetylsalicylic acid (100, 300, and 500 mg/kg), piroxicam (5, 10, and 20 mg/kg) and sodium diclofenac (10, 25, 50, and 100 mg/kg), and of their interaction with zaprinast (5 mg/kg) and IBMX (10 mg/kg), on intragastric concentrations of cyclic GMP and the gastric erosive index in rats. All determinations were done 3 hr after the NSAID was given. All NSAIDs induced dose-dependent decreases in mucosal concentrations of cyclic GMP, which correlated inversely with the surface area showing mucosal injury. In contrast, cyclic GMP concentrations remained normal, and no intragastric damage was seen in rats given zaprinast (cyclic GMP-specific phosphodiesterase inhibitor) or IBMX (non-specific phosphodiesterase inhibitor) or in combination with NSAIDs. These findings are in line with the hypothesis that cyclic GMP is involved in the biochemical mechanisms of NSAID-induced gastric injury. 相似文献
993.
This is a study to define the profile of chemokine receptors expressed on isolated infiltrating lymphocytes in human abdominal aortic aneurysms (AAAs), and to examine their role in lymphoid recruitment. AAA T-lymphocytes were CXCR4-positive, CCR7-negative and partially CXCR3 and CCR5-positive. Functionally, AAA T-cells were proinflammatory effector cells, as they produced IFN-γ and granzyme A. AAA B-lymphocytes were CXCR4-positive and exhibited low CXCR5 expression. A relevant feature of infiltrating T- and B-lymphocytes was the high intensity of CXCR4 expression and the capability to migrate to CXCL12. CXCL12-producing cells were found in the adventitia of AAA. These cells were CD45-negative and partially VCAM-1 and DR-positive. In summary, the present results suggest that CXCR4, expressed on infiltrating lymphocytes, and CXCL12, expressed on stromal cells, is involved in the recruitment of lymphocytes within the arterial wall in AAA. 相似文献
994.
Muscelli E Mingrone G Camastra S Manco M Pereira JA Pareja JC Ferrannini E 《The American journal of medicine》2005,118(1):51-57
PURPOSE: To compare the effects of equivalent weight loss induced by two bariatric surgical techniques on insulin action in severely obese patients. METHODS: Eighteen nondiabetic patients with severe obesity (mean [+/- SD] body mass index: 53.5 +/- 9.0 kg/m(2)) and 20 sex- and age-matched lean subjects (body mass index: 23.8 +/- 3.0 kg/m(2)) underwent metabolic studies, including measurement of insulin sensitivity by the insulin clamp technique. Patients then underwent either vertical banded gastroplasty with Roux-en-Y gastric bypass, or biliopancreatic diversion, and were restudied at 5 to 6 months and again at 16 to 24 months postsurgery. RESULTS: At baseline, patients were hyperinsulinemic (194 +/- 47 pmol/L vs. 55 +/- 25 pmol/L, P < 0.0001), hypertriglyceridemic (1.56 +/- 0.30 mmol/L vs. 0.78 +/- 0.32 mmol/L, P < 0.0001), and profoundly insulin resistant (insulin-mediated glucose disposal: 20.8 +/- 4.4 micromol/min/kg fat-free mass vs. 52.0 +/- 10.1 micromol/min/kg, P < 0.0001) as compared with controls. Weight loss by the two procedures was equivalent in both amount (averaging -53 kg) and time course. In the gastric bypass group, insulin sensitivity improved (23.8 +/- 6.0 micromol/min/kg at 5 months and 33.7 +/- 11.3 micromol/min/kg at 16 months, P < 0.01 vs. baseline and controls). In contrast, in the biliopancreatic diversion group, insulin sensitivity was normalized already at 6 months (52.5 +/- 12.4 micromol/min/kg, P = 0.72 vs. controls) and increased further at 24 months (68.7 +/- 9.5 micromol/min/kg, P < 0.01 vs. controls) despite a persistent obese phenotype (body mass index: 33.2 +/- 8.0 kg/m(2)). CONCLUSION: In surgically treated obese patients, insulin sensitivity improves in proportion to weight loss with use of predominantly restrictive procedures (gastric bypass), but is reversed completely by predominantly malabsorptive approaches (biliopancreatic diversion) long before normalization of body weight. Selective nutrient absorption and gut hormones may interact with one another in the genesis of the metabolic abnormalities of obesity. 相似文献
995.
Resino S Galán I Pérez A Ramos JT Bellón JM Fontelos PM de José MI Gutiérrez MD Cabrero E Muñoz-Fernández MA 《AIDS research and human retroviruses》2005,21(5):398-406
We evaluated the effect of salvage antiretroviral therapy with lopinavir/ritonavir (LPV/r) on the immune system of heavily antiretroviral pretreated HIV-infected children. We carried out a longitudinal study in 20 antiretroviral experienced HIV-infected children to determine the changes in several immunological parameters (T cell subsets, thymic function) every 3 months during 18 months of follow-up on salvage therapy with LPV/r. Statistical analyses were performed with the Wilcoxon test, taking as a reference the basal value at the entry in the study. HIV-infected children showed an increase of CD4+ T cells, a decrease in CD8+ T cells, and an increase in T cell rearrangement excision circle (TRECs) levels. The percentage of HIV children with undetectable viral load (VL < or = 400 copies/ml) increased significantly (p = 0.007) and the percentage with SI viral phenotype decreased significantly (p = 0.002) at the end of the study. Thus, the viral phenotype changed to NSI/R5 after salvage therapy with LPV/r. Interestingly, we observed a significant decrease of memory (CD4+ CD45RO+) and a moderate decrease of activated (CD4+ HLA-DR+, CD4+ HLA-DR+CD38, CD4+, CD45RO+HLA-DR+) CD4+ T cells during the follow-up. On the other hand, memory (CD8+ CD45RO+ and CD8+ CD45RO+CD38+), activated (CD8+ HLA-DR+CD38+, CD8+ HLA-DR+, CD8+ CD38+), and effector (CD8+ CD57+, CD8+ CD28(-)CD57+) CD8+ T cells had a very significant decrease during follow-up. Our data indicate an immune system reconstitution in heavily pretreated HIV-infected children in response to salvage therapy with LPV/r as a consequence of a decrease in immune system activation and an increase in thymic function. 相似文献
996.
Portilla J Boix V Garcia-Henarejos JA Llopis C Martínez-Madrid O Gimeno A Sánchez-Paya J Merino E 《International journal of STD & AIDS》2005,16(12):807-810
To analyse if a four-drug combination including two protease inhibitors (PIs) accelerates viral decay and suppression as compared with standard triple therapy in heavily immunosuppressed HIV-1 infected patients, an open label clinical trial was designed. PIs naive patients receiving their first highly active antiretroviral therapy were included if their CD4 cell count was lower than 200/mm3 and their HIV viral load (VL) >100,000 RNA copies/mL. Every patient received two analogues and was randomized in two groups receiving either one PI (saquinavir soft gel capsule) or two PIs (saquinavir + nelfinavir). Viral efficacy (VL <50), time to reach VL <50, viral clearance rate constant and plasmatic elimination half-life were determined. In all, 30 patients were enrolled. No viral variable was significatively improved by the four-drug combination in the short term. No clinical benefit should be expected with a four-drug (two PIs) regimen in patients with low CD4+ cell count and high VL. 相似文献
997.
Pagliano P Costantini S Gradoni L Faella FS Spasiano A Mascarella G Prossomariti L Fusco U Ricchi P 《The American journal of tropical medicine and hygiene》2008,79(1):9-11
A 37-year-old splenectomized man affected by beta-thalassemia and chronic hepatitis, recently treated with pegylated interferon-alpha (Peg-IFN), was admitted because of elevated fever lasting 3 months and unresponsiveness to broad-spectrum antibiotics. Laboratory studies showed white blood cell and platelet counts within the normal range but lower than observed before Peg-IFN treatment and an elevated erythrocyte sedimentation rate. The blood transfusion rate was reported to be increased compared with the period preceding Peg-IFN treatment. A diagnosis of visceral leishmaniasis (VL) was made after Leishmania amastigotes were identified from Giemsa-stained smears of bone marrow aspirates. Cure occurred after liposomal amphotericin B was administered. Symptoms of VL may be difficult to distinguish from the manifestations of Peg-IFN intolerance. We suggest that VL must be suspected in any immunodepressed patient with an unexplained fever and a history of exposure in an endemic area. 相似文献
998.
Serrano D Carrión R Balsalobre P Miralles P Berenguer J Buño I Gómez-Pineda A Ribera JM Conde E Díez-Martín JL;Spanish Cooperative Groups GELTAMO GESIDA 《Experimental hematology》2005,33(4):487-494
OBJECTIVE: To evaluate feasibility, safety, and efficacy of peripheral blood stem cell collection (PBSCC) and autologous stem cell transplantation (ASCT), to treat patients diagnosed of high-risk or relapsed HIV-associated lymphoma (HIV+ Ly), responding to highly active antiretroviral therapy (HAART). METHODS: Prospective and multicentric study in patients with high-risk or relapsed chemosensitive HIV+ Ly, candidate for consolidation with ASCT. Eligibility criteria were similar to those of HIV- lymphoma. HAART was aimed to be maintained during the procedure. RESULTS: Fourteen patients were admitted. Adequate PBSCC was obtained from all patients (median CD34+ cells was 4.7 x 10(6)/kg). Three patients died before ASCT; two had disease progression and one died from VHC-liver failure. Eleven transplanted patients showed neutrophil engraftment after a median time of 16 days (range, 9-33 days), and nine patients showed platelet engraftment after a median time of 20 days (range, 11-36 days). CD4+ cell counts and HIV viral load (VL) were appropriately preserved along the procedure. No patients died from treatment-related complications. One patient died from lymphoma progression (day +19), and another died in complete remission (CR) with undetectable VL, 15 months after transplant, due to infection. One patient relapsed at 32 months after ASCT. The remaining eight patients are alive in CR with an event-free survival of 65% and a median follow-up of 30 months after ASCT (range, 7-36 months). CONCLUSIONS: These results show that feasibility, safety, and efficacy of PBSCC and ASCT in HIV+ Ly patients responding to HAART are similar to those observed in the HIV- lymphoma setting. 相似文献
999.
Alfonso Anselmi JoséAngel Suarez Guillermo Anselmi Frederico Moleiro Claudia de Suarez Victor Ruesta 《The American journal of cardiology》1975,35(1):97-102
Seventeen year old identical twin brothers with no family history of cardiopathy began experiencing palpitations almost simultaneously. In both, examination revealed marked cardiomegaly and hypokinesia of the ventricular walls, and clinical and radiologic signs of progressive cardiac failure developed a few days later. Both boys died suddenly, 49 days and 5 months, respectively, after the initial examination. Electrocardiographic and vectorcardiographic studies revealed a severe intraventricular conduction disturbance that coincided with histologic changes in the myocardial tissue, including profuse interstitial fibrosis, hypertrophy and degeneration of the myocardial fibers, aberrant arrangement of the muscular fibers and considerable alteration of the structure of cardiac tissue. In the absence of hereditary and chromosomal factors, and excluding possible viral intervention during fetal life, it is believed that a teratogenic factor can produce the structural alterations of the tissue and derangement of the fibers observed in these hearts.The irregular contractions of the heart at the level of the net-like meshwork, disarrangement of myocardial fibers, and adaptative mechanisms of the heart inherent in the destruction of the contractile tissue contributed to the functional cardiac disorders that resulted in congestive heart failure and sudden death in these twins. 相似文献
1000.
Prospective endoscopic study of 150 patients revealed chronic gastritis in 109 (72.6%), gastric ulcer in 6 (4%), chronic duodenitis in 9 (6%) and duodenal ulcer in 26 (17.4%). Searching for Helicobacter pylori, positive urease test was observed in 103 (68.67%), histologic evidence in 104 (69.33%) and positive serologic test in 98 (65.33%), without statistical difference. The urease test is recommended in the diary medical practice, for the patients who also will benefit themselves with the endoscopic diagnosis. On the other hand, the serologic test is useful when the endoscopy of the upper digestive tract cannot or must not be realized. 相似文献