首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2073篇
  免费   449篇
  国内免费   9篇
耳鼻咽喉   3篇
儿科学   26篇
妇产科学   40篇
基础医学   104篇
口腔科学   13篇
临床医学   770篇
内科学   309篇
皮肤病学   10篇
神经病学   204篇
特种医学   45篇
外科学   363篇
综合类   64篇
预防医学   264篇
眼科学   10篇
药学   103篇
肿瘤学   203篇
  2023年   64篇
  2022年   11篇
  2021年   25篇
  2020年   28篇
  2019年   23篇
  2018年   91篇
  2017年   105篇
  2016年   97篇
  2015年   100篇
  2014年   87篇
  2013年   109篇
  2012年   77篇
  2011年   84篇
  2010年   64篇
  2009年   69篇
  2008年   88篇
  2007年   90篇
  2006年   83篇
  2005年   107篇
  2004年   61篇
  2003年   56篇
  2002年   63篇
  2001年   64篇
  2000年   53篇
  1999年   49篇
  1998年   42篇
  1997年   46篇
  1996年   37篇
  1995年   44篇
  1994年   40篇
  1993年   24篇
  1992年   40篇
  1991年   39篇
  1990年   35篇
  1989年   46篇
  1988年   35篇
  1987年   30篇
  1986年   24篇
  1985年   27篇
  1984年   28篇
  1983年   25篇
  1982年   14篇
  1979年   14篇
  1975年   14篇
  1974年   12篇
  1972年   8篇
  1969年   9篇
  1929年   15篇
  1928年   26篇
  1927年   11篇
排序方式: 共有2531条查询结果,搜索用时 15 毫秒
31.
32.
PURPOSE: To assess the maximum tolerated dose, toxicities, pharmacokinetics, and antileukemic activity of topotecan and carboplatin in adults with recurrent or refractory acute leukemias. EXPERIMENTAL DESIGN: Patients received topotecan and carboplatin by 5-day continuous infusion at nine dose levels. Patients achieving a complete remission received up to two additional courses for consolidation. Plasma topotecan and ultrafilterable platinum were assayed on days 1 to 5. In addition, pretreatment levels of various polypeptides in leukemic cells were examined by immunoblotting to assess possible correlations with response. RESULTS: Fifty-one patients received a total of 69 courses of therapy. Dose-limiting toxicity consisted of grade 4/5 typhlitis and grade 3/4 mucositis after one course of therapy or grade 4 neutropenia and thrombocytopenia lasting >50 days when a second course was administered on day 21. Among 45 evaluable patients, there were 7 complete remissions, 2 partial remissions, 1 incomplete complete remission, and 1 reversion to chronic-phase chronic myelogenous leukemia. Topotecan steady-state plasma concentrations increased with dose. No accumulation of topotecan or ultrafilterable platinum occurred between days 1 and 5 of therapy. Leukemic cell levels of topoisomerase I, checkpoint kinase 1, checkpoint kinase 2, and Mcl-1 correlated with proliferating cell nuclear antigen but not with response. In contrast, low Bcl-2 expression correlated with response (P = 0.014, Mann-Whitney U test). CONCLUSIONS: The maximum tolerated dose was 1.6 mg/m(2)/d topotecan plus 150 mg/m(2)/d carboplatin. The complete remission rate in a heavily pretreated population was 16% (33% at the highest three dose levels). Responses seem to correlate with low pretreatment blast cell Bcl-2 expression.  相似文献   
33.
PURPOSE: The objective of this study was to further investigate the efficacy and safety of low-dose outpatient chemobiotherapy in patients with unresectable metastatic melanoma. PATIENTS AND METHODS: Thirty-one patients with histologically confirmed unresectable measurable metastatic melanoma were enrolled onto an open-label, multicenter phase II study. The treatment regimen consisted of oral temozolomide followed by subcutaneous biotherapy with granulocyte macrophage colony-stimulating factor, interferon-alfa, and recombinant interleukin-2 (rIL-2). RESULTS: Twenty-eight patients (90%) had M1c disease, and 58% had three or more sites of metastasis. Four patients (13%), all with M1c disease, had a complete response, and four patients had a partial response. The median progression-free survival was 4.9 months and the median overall survival was 13.1 months. Two patients (6%) developed CNS metastasis as the first site of disease progression, and 7 (23%) of 30 experienced CNS progression after receiving chemobiotherapy. A total of 112 cycles of therapy were administered. Toxicity occurred in 78% of the cycles and was grade 1 or 2 in the majority of cases and easily managed. Grade 4 toxicity occurred in 3% of the cycles. CONCLUSION: This low-dose chemobiotherapy combination produces clinical responses in patients with metastatic melanoma, even in those with M1c disease, is well tolerated, and allows home dosing. It offers a reasonable alternative to high-dose regimens, such as high-dose biochemotherapy or rIL-2 requiring prolonged periods of hospitalization, or single agent outpatient regimens, such as dacarbazine, which is usually not effective in patients with M1c disease. Furthermore, it may protect against the development of brain metastases.  相似文献   
34.
Three term neonates presented with an unusual combination of skin changes (sclerema) and joint contractures at birth. In each case a prolonged period of fetal hyporeactivity was reported by the mother. Each child demonstrated a number of clinical findings consistent with chronic fetal hypoxia. Each child recovered with normal joint function. We postulate that sclerema neonatorum and joint contractures are another, though poorly recognized sequela of chronic in utero hypoxia and are preceded by a prolonged period of diminished fetal activity.  相似文献   
35.
BACKGROUND: Breast-conservation therapy (BCT), including wide local excision and postoperative irradiation, is considered standard treatment for early-stage invasive ductal carcinoma (IDC). The use of BCT in patients with invasive lobular carcinoma (ILC) has been questioned because of concerns regarding ipsilateral breast recurrence and risk of bilateral breast cancer. We evaluated our institutional experience with BCT and compared treatment outcomes for ILC with those for IDC. METHODS: A review of our BCT database revealed 84 patients with ILC and 1,126 with IDC with stage I or II disease treated with BCT and radiation between 1976 and 1999. We evaluated local-regional recurrence, disease-specific survival, and contralateral breast cancer rates in both groups. RESULTS: The 5- and 10-year local-regional recurrence rates for the ILC group were 1% and 7%, respectively, and 4% and 9%, respectively, for the IDC group (P = .70). There were no significant differences in the 5- and 10-year disease-specific survival rates between the groups. Contralateral breast cancer occurred in 11.3% of patients with IDC and 11.9% of patients with ILC. CONCLUSIONS: BCT achieves similar local-regional control and survival outcomes in selected patients with ILC or IDC. Breast-conservation therapy is an appropriate treatment strategy for patients with early-stage invasive lobular carcinoma.  相似文献   
36.
37.
Background and objectives: The objective of this study was to investigate the effects of desensitization protocols using intravenous Ig with or without plasmapheresis in patients with donor-specific anti-HLA antibodies on prevention of antibody-mediated rejection and downregulation of donor-specific antibodies.Design, setting, participants, & measurements: Thirty-five complement-dependent cytotoxicity T cell cross-match–negative but complement-dependent cytotoxicity B cell and/or flow cytometry cross-match–positive kidney transplant recipients were treated with high-dosage intravenous Ig plus Thymoglobulin induction treatment. Donor-specific antibody strength was stratified as strong, medium, or weak by Luminex flow beads. Group 1 patients had weak/moderate and group 2 strong donor-specific antibodiesResults: Whereas no group 1 patients had acute rejection, 66% of group 2 had acute rejection (44% antibody-mediated rejection, 22% cellular rejection). The protocol was then changed to the addition of peritransplantation plasmapheresis to patients with strong donor-specific antibodies (group 3). This change resulted in a dramatic decrease in the acute rejection rate to 7%. During a median 18 mo of follow-up, patient survival was 100, 100, and 93% and graft survival was 100, 78, and 86% in groups 1, 2, and 3, respectively. During follow-up, 17 (52%) patients lost donor-specific antibodies completely, and 10 (30%) lost some of donor-specific antibodies and/or decreased the strength of existing donor-specific antibodies.Conclusions: These results indicated that in patients with strong donor-specific antibodies, the addition of plasmapheresis to high-dosage intravenous Ig decreases the incidence of acute rejection. The majority of the patients, whether they received intravenous Ig alone or with plasmapheresis, lost their donor-specific antibodies during follow-up.Donor-specific anti-HLA antibodies (DSA) in patients who are sensitized through pregnancy, previous blood transfusions, or organ transplantation is an important obstacle in kidney transplantation. Sensitized patients wait longer on the deceased-donor transplantation list, may not receive a transplant, and may have greater morbidity and mortality. Some sensitized patients may have living donor candidates, but transplantation cannot be performed because of cross-match positivity. Recent desensitization protocols using the combination of plasmapheresis (PP) or immunoadsorption to remove DSA and/or intravenous Ig (IVIG) and rituximab to downregulate antibody-mediated immune responses have made kidney transplantation feasible by abrogating complement-dependent cytotoxicity (CDC) T cell cross-match positivity. In previous studies, two protocols were examined: High-dosage IVIG (2.0 g/kg) (13) and PP with low-dosage IVIG (100 mg/kg after each PP session) (48); however, acute antibody-mediated rejection (AMR) continued to be an important barrier and was still observed in at least 30 to 40% of the recipients included in these desensitization protocols, even when rituximab was added to the protocol.Whereas CDC T cell cross-match positivity is an absolute contraindication to kidney transplantation, the clinical significance of CDC B cell or flow cytometry (FC) T and/or B cell cross-match positivity are less clear. Most studies have demonstrated that CDC T cell cross-match–negative but CDC B or FC T/B cell cross-match–positive patients with DSA are at higher risk for developing acute cellular, antibody-mediated, and chronic rejection and graft loss (9,10). The role of desensitization protocols for these patients has not been studied in a large cohort. We previously reported our initial experience using low-dosage IVIG (300 mg/kg) and Thymoglobulin induction treatment in 15 patients (11,12). Because of early AMR in three patients, the IVIG dosage was increased to a total of 2.0 mg/kg in subsequent patients. Now, we present our experience in CDC T cell–negative but CDC B cell or FC T and/or B cell cross-match–positive kidney transplant recipients with DSA, who were stratified according to mean fluorescence indices of Luminex flow beads. The results showed that patients with strong DSA were at much higher risk for developing acute AMR early after transplantation, and the addition of peritransplantation PP to high-dosage IVIG and Thymoglobulin treatment significantly decreased the incidence of AMR. The majority of the patients, whether they received IVIG alone or with PP, lost DSA during follow-up.  相似文献   
38.
Patient preference studies provide important data on the impact of asthma symptoms and the effects of medication on patients' quality of life and functional activity levels. Such studies are lacking in the evaluation of short-acting beta2-agonist treatment for asthma, especially for racemic albuterol. The introduction in 1999 of levalbuterol, the (R)-isomer of racemic albuterol, has provided the opportunity to assess patient preference between racemic albuterol and levalbuterol. Studies with levalbuterol, 1.25 mg, indicated greater bronchodilation than and comparable beta2-mediated side effects to the standard 2.5-mg dose of racemic albuterol, while lower doses of levalbuterol (0.63 mg) provided comparable bronchodilation with reduced beta2-mediated side effects in patients with asthma. This study evaluated treatment satisfaction by the caregivers of children with asthma who currently use and/or have used either levalbuterol (n = 66) or racemic albuterol (n = 76). Twenty-minute-long telephone surveys were administered to caregivers, asking them to rate satisfaction with their child's asthma treatment and provide reasons for satisfaction and dissatisfaction. Significantly more caregivers administering levalbuterol (92%) were "extremely" or "very satisfied" with therapy versus those who currently administered racemic albuterol (51%; p = 0.001). Symptom relief was graded 8.7 (out of 10) for levalbuterol treatment versus 7.5 for racemic albuterol (p = 0.001). Although these differences, in part, may have been influenced by some of the study limitations (e.g., open-label, non-placebo-controlled and nonrandomized design, and potential caregiver recall bias), the statistically significant differences consistently favored levalbuterol and are consistent with results obtained from other clinical studies. The efficacy, dosing flexibility, and improved side effect profile of levalbuterol were the sources of greatest satisfaction for parents/ caregivers in the levalbuterol group. This study supports the conclusion that the majority of caregivers of children with asthma who have experience with both levalbuterol and racemic albuterol prefer levalbuterol over racemic albuterol.  相似文献   
39.
We investigated the effects of the antimycotic agent amphotericin B (AmB) on the phagocytic activity of the isolated perfused rat liver. At a concentration of 5 microM, the drug markedly reduced the clearance of latex beads by the liver as compared to control preparations. Scanning electron microscopy observations showed that latex beads were attached only to Kupffer cells. A liver scan performed infusing 99Tc-colloidal albumin showed that AmB depressed the uptake of the colloid in all hepatic lobes, with no focal defects. Both in control and AmB experiments no trypan blue uptake occurred. The pretreatment of the perfused liver with the calcium antagonist nifedipine prevented the decrease in phagocytosis induced by AmB. In addition, AmB had no effect on livers perfused with a Ca2(+)-free medium. A decrease in the phagocytic capacity of the perfused liver was also observed after the administration of the Ca2(+)-ionophore A23187. The observations suggest that AmB may exert an intrinsic toxicity on the Kupffer cells, which is, at least in part, responsible for the decrease in phagocytosis induced by the drug. This effect may be of relevance to clinical situations and deserves careful consideration.  相似文献   
40.
Insulin receptors on leukemia and lymphoma cells   总被引:1,自引:0,他引:1  
Chen  PM; Kwan  SH; Hwang  TS; Chiang  BN; Chou  CK 《Blood》1983,62(2):251-255
Tumor cells obtained from leukemia and lymphoma patients were investigated for specific insulin receptors. Using radioactive 125I- labeled insulin, specific insulin binding sites were demonstrated on most acute lymphocytic leukemia (ALL) and acute myelocytic leukemia (AML) cells, including acute promyelocytic leukemia (APL), chronic myelocytic leukemia (CML), and acute monocytic leukemia (AMoL) cells. Insulin receptors were not found on chronic lymphocytic leukemia (CLL) and malignant lymphoma (ML) cells. Specific insulin binding sites were also found on monocytes and thymocytes after treatment with phytohemagglutinin (PHA-P), but not on inactivated tonsil cells, peripheral blood lymphocytes, or thymocytes. There was no inverse correlation between the content of insulin receptors and the basal level of circulating insulin. These data suggest that the insulin receptor may be a new marker of acute leukemia and chronic myelocytic leukemia.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号