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   1791篇
  免费   107篇
  国内免费   36篇
耳鼻咽喉   9篇
儿科学   52篇
妇产科学   10篇
基础医学   154篇
口腔科学   30篇
临床医学   162篇
内科学   755篇
皮肤病学   100篇
神经病学   59篇
特种医学   153篇
外国民族医学   21篇
外科学   94篇
综合类   19篇
预防医学   104篇
眼科学   14篇
药学   139篇
肿瘤学   59篇
  2022年   5篇
  2021年   12篇
  2020年   8篇
  2019年   10篇
  2018年   22篇
  2017年   9篇
  2016年   12篇
  2015年   21篇
  2014年   33篇
  2013年   49篇
  2012年   68篇
  2011年   54篇
  2010年   56篇
  2009年   74篇
  2008年   73篇
  2007年   91篇
  2006年   98篇
  2005年   81篇
  2004年   67篇
  2003年   76篇
  2002年   86篇
  2001年   79篇
  2000年   93篇
  1999年   74篇
  1998年   50篇
  1997年   47篇
  1996年   46篇
  1995年   39篇
  1994年   43篇
  1993年   35篇
  1992年   34篇
  1991年   32篇
  1990年   32篇
  1989年   41篇
  1988年   38篇
  1987年   33篇
  1986年   34篇
  1985年   27篇
  1984年   15篇
  1983年   11篇
  1982年   16篇
  1981年   15篇
  1980年   15篇
  1979年   15篇
  1978年   8篇
  1976年   11篇
  1975年   9篇
  1972年   4篇
  1970年   5篇
  1969年   4篇
排序方式: 共有1934条查询结果,搜索用时 15 毫秒
41.
42.
PURPOSE: Acquired angioedema type 1 is characterized by a C1 inhibitor deficiency in patients with lymphoproliferative disorders, whereas acquired angioedema type 2 is characterized by anti-C1 inhibitor antibodies, and has not been thought to be associated with lymphoproliferative disease. We studied the clinical features, complement profiles, and associated diseases in 19 new patients with diagnosed acquired angioedema type 2. SUBJECTS AND METHODS: Plasma concentrations and functional activity of complement components were measured by conventional techniques. Functional C1 inhibitor activity was assessed by a chromogenic assay. Autoantibodies to C1 inhibitor were detected using an enzyme-linked immunosorbent assay. RESULTS: The 11 men and 8 women (median age, 60 years) presented with recurrent attacks of angioedema. All patients had detectable anti-C1 inhibitor antibodies in serum. A monoclonal gammopathy was detected in 12 patients (63%) at the time of diagnosis, 11 of whom had an immunoglobulin peak of the same heavy- and light-chain isotypes as the acquired anti-C1 inhibitor antibody. Three of these 12 patients developed a malignant lymphoproliferative disease. CONCLUSION: As with type 1 disease, a large proportion of patients with acquired angioedema type 2 have a lymphoproliferative disorder.  相似文献   
43.
OBJECTIVE: To analyze the results and complications of ovulation induction therapy (OIT) in women with systemic lupus erythematosus (SLE) and/or the antiphospholipid syndrome (APS). METHODS: A retrospective study of 21 women followed in a single tertiary-referral French center who underwent 114 OIT cycles with or without in vitro fertilization and embryo transfer (IVFET). RESULTS: Before OIT, SLE was present in 6 women, APS in 3, SLE-related APS in 3, and discoid lupus in 1. Eight women had no identified disease and underwent 36 cycles of OIT. Diagnosis (SLE, n = 3; primary APS, n = 5) was made after OIT complication: spontaneous abortion (n = 5), SLE flare (n = 2), and thrombophlebitis (n = 1). Five women with known disease intentionally concealed their history from their gynecologists and underwent 34 cycles. Forty-four cycles were planned in 11 women, in 3 of them after complications of prior OIT performed without particular therapy and monitoring. Eighteen pregnancies occurred, which ended in 9 live births, 4 fetal deaths, and 5 embryonic losses. The pregnancy rate was higher with gonadotropin and/or gonadotropin-releasing hormone analog (GnRHa) (25% of cycles) than with clomiphene (4% of cycles, P <.0001). When the gynecologists did not know the underlying disease, three-quarters of pregnancies induced by OIT with IVFET ended in embryonic losses or fetal deaths. In contrast, 6 of 7 pregnancies induced by planned OIT with IVFET ended in live births (P <.0001). Phlebothromboses were observed only with gonadotropin treatment. The SLE flare rate was higher with gonadotropin and/or GnRHa (27% of cycle) than with clomiphene (6%, NS). It also was higher (30%) when the gynecologists did not know the underlying disease than in the planned procedures (10%, NS). CONCLUSIONS: The OIT may precipitate SLE or APS. A careful review of the patient's history and appropriate laboratory tests should be undertaken before OIT. Clomiphene complications are rare. When gonadotropins are prescribed, preventive anti-inflammatory therapy should be considered in women with SLE, in addition to heparin and/or anti-aggregant therapy in patients with asymptomatic anti-phospholipid antibodies or prior thrombotic events.  相似文献   
44.
To describe the clinical and immunologic characteristics of patients with adrenal involvement and antiphospholipid syndrome (APS), we conducted a computer-assisted (PubMed) search of the literature to identify all cases of primary adrenal insufficiency associated with antiphospholipid antibodies published in English, French, and Spanish from 1983 (when APS was first defined) through March 2002. We reviewed 86 patients (80 from the literature plus 6 from our cohort); 55% were male, and the mean age at presentation was 43 +/- 16 years. Sixty-one (71%) patients had primary APS, and 14 (16%) had systemic lupus erythematosus. In 31 (36%) patients, adrenal insufficiency was the first clinical manifestation of APS. Abdominal pain was present in 55% of patients, followed by hypotension (54%), fever (40%), nausea or vomiting (31%), weakness or fatigue (31%), and lethargy or altered mental status (19%). The main finding in imaging techniques was compatible with adrenal hemorrhage (59%) and in histopathologic study was a hemorrhagic infarction with vessel thrombosis (55%). Lupus anticoagulant was detected in 97% of patients and the anticardiolipin antibodies titer was positive in 93% of patients. Most patients (95%) were positive for the IgG isotype of anticardiolipin antibodies, whereas 40% were positive for the IgM isotype. Baseline cortisol levels were decreased in 98% of patients, ACTH hormone levels were increased in 96% of patients, and the cosyntropin stimulation test was positive in 100% of patients tested. Steroid replacement therapy was the most frequent treatment (84%), followed by anticoagulation (52%) and aspirin (6%). Thirty-two of 35 (91%) patients with prolonged anticoagulant therapy were in good health with a mean follow-up of 25 months, whereas 25 of the 69 (36%) patients with outcome data available had died. The results of the present review stress the clinical importance of systematic screening for lupus anticoagulant and anticardiolipin antibodies in all cases of adrenal hemorrhage or infarction. An initial screening for hypoadrenalism is mandatory in any antiphospholipid antibody-positive patient who complains of abdominal pain and undue weakness or asthenia.  相似文献   
45.
46.
BACKGROUND & AIMS: Shwachman syndrome is an inherited condition with multisystemic abnormalities, including exocrine pancreatic dysfunction. The aim of this study was to evaluate the occurrence and progression of features in a large cohort of patients. METHODS: Clinical records of 25 patients with Shwachman syndrome were reviewed. RESULTS: Mean birth weight (2.92 +/- 0.51 kg) was at the 25th percentile. However, by 6 months of age, mean heights and weights were less than the 5th percentile. After 6 months of age, growth velocity was normal. Severe fat maldigestion due to pancreatic insufficiency was present in early life (fecal fat, 26% +/- 17% of fat intake; age, < 2 years). Serial assessment of exocrine pancreatic function showed persistent deficits of enzyme secretion, but 45% of patients showed moderate age-related improvements leading to pancreatic sufficiency. Neutropenia was the most common hematologic abnormality (88%), but leukopenia, thrombocytopenia, and anemia were also frequently encountered. Patients with hypoplasia of all three bone marrow cellular lines (n = 11) had the worst prognosis; 5 patients died, 2 of sepsis and 3 of acute myelogenous leukemia. Other findings included hepatomegaly and/or abnormal liver function test results and skeletal abnormalities. CONCLUSIONS: A wide and varied spectrum of phenotypic abnormalities among patients with Shwachman syndrome is described. Pancreatic acinar dysfunction is an invariable abnormality. Patients with severe bone marrow involvement may have a guarded prognosis. (Gastroenterology 1996 Dec;111(6):1593-602)  相似文献   
47.

Background

Like many patients with diabetes, Department of Veterans Affairs (VA) patients frequently fall short of self-management goals and experience multiple barriers to self-care. Health information technologies (HITs) may provide the tools that patients need to manage their illness under the direction of their primary care team.

Methods

We describe several ongoing projects focused on HIT resources for self-management in VA. VA researchers are developing HITs that seek to bolster a variety of potential avenues for self-management support, including patients′ relationships with other patients, connections with their informal care networks, and communication with their health care teams.

Results

Veterans Affairs HIT research projects are developing services that can address the needs of patients with multiple challenges to disease self-care, including multimorbidity, health literacy deficits, and limited treatment access. These services include patient-to-patient interactive voice response (IVR) calling systems, IVR assessments with feedback to informal caregivers, novel information supports for clinical pharmacists based on medication refill data, and enhanced pedometers.

Conclusion

Large health care systems such as the VA can play a critical role in developing HITs for diabetes self-care. To be truly effective, these efforts should include a continuum of studies: observational research to identify barriers to self-management, developmental studies (e.g., usability testing), efficacy trials, and implementation studies to evaluate utility in real-world settings. VA HIT researchers partner with operations to promote the dissemination of efficacious services, and such relationships will be critical to move HIT innovations into practice.  相似文献   
48.
Porter  CD; Parkar  MH; Levinsky  RJ; Collins  MK; Kinnon  C 《Blood》1993,82(7):2196-2202
Chronic granulomatous disease (CGD) is an inherited immunodeficiency resulting from the inability of an individual's phagocytes to produce superoxide anions because of defective NADPH oxidase. The disease may be treated by bone marrow transplantation and as such is a candidate for somatic gene therapy. Two thirds of patients have defects in an X- linked gene (X-CGD) encoding gp91-phox, the large subunit of the membrane cytochrome b-245 component of NADPH oxidase. Epstein-Barr virus-transformed B-cell lines from patients with CGD provide a model system for the disease. We have used retrovirus-mediated expression of gp91-phox to reconstitute functionally NADPH oxidase activity in B-cell lines from three unrelated patients with X-CGD. The protein is glycosylated and membrane associated, and the reconstituted oxidase is appropriately activated via protein kinase C. The kinetics of superoxide production by such reconstituted cells is similar to that of normal B-cell lines. These data show the potential of gene therapy for this disease.  相似文献   
49.
Time-to-event analysis is frequently used in medical research to investigate potential diseasemodifying treatments in neurodegenerative diseases. Potential treatment effects are generally evaluated using the logrank test, which has optimal power and sensitivity when the treatment effect (hazard ratio) is constant over time. However, there is generally no prior information as to how the hazard ratio for the event of interest actually evolves. In these cases, the logrank test is not necessarily the most appropriate to use. When the hazard ratio is expected to decrease or increase over time, alternative statistical tests such as the Fleming-Harrington test, provide a better sensitivity. An example of this comes from a large, five-year randomised, placebo-controlled prevention trial (GuidAge) in 2854 community-based subjects making spontaneous memory complaints to their family physicians, which evaluated whether treatment with EGb761® can modify the risk of developing AD. The primary outcome measure was the time to conversion from memory complaint to Alzheimer’s type dementia. Although there was no significant difference in the hazard function of conversion between the two treatment groups according to the preplanned logrank test, a significant treatment-by-time interaction for the incidence of AD was observed in a protocol-specified subgroup analysis, suggesting that the hazard ratio is not constant over time. For this reason, additional post hoc analyses were performed using the Fleming-Harrington test to evaluate whether there was a signal of a late effect of EGb761®. Applying the Fleming-Harrington test, the hazard function for conversion to dementia in the placebo group was significantly different from that in the EGb761® treatment group (p = 0.0054), suggesting a late effect of EGb761®. Since this was a post hoc analysis, no definitive conclusions can be drawn as to the effectiveness of the treatment. This post hoc analysis illustrates the interest of performing another randomised clinical trial of EGb761® explicitly testing the hypothesis of a late treatment effect, as well as of using of better adapted statistical approaches for long term preventive trials when it is expected that prevention cannot have an immediate effect but rather a delayed effect that increases over time.  相似文献   
50.
Various dermatologic manifestations are observed in the different lupus subsets. Lupus lesions are most frequently characterized by a dermoepidermal dermatitis. Other lesions, vascular or nonvascular, are essentially present in association with systemic lupus erythematosus. Acute, subacute and chronic lupus erythematosus are distinguishable according to their clinical aspects, pathological features and their evolution. Acute lesions are either localized to the midface or widespread. Subacute lesions may be annular or psoriasiform. Chronic lupus erythematosus includes localized or widespread discoid lupus, lupus tumidus, chilblain lupus and panniculitis. Therapy of cutaneous lupus is mainly based on antimalarials and avoidance of sun exposure. In refractory cutaneous lupus, no universal guidelines are available. Except for acrosyndromes and urticaria-like lesions, vascular lesions may be due to vasculitis or thrombosis. An accurate diagnosis is necessary, since therapeutic management is quite different in these two conditions. Nonvascular and nonlupus lesions are numerous and some of them require specific treatment, such as dapsone for bullous lupus.  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