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   17514篇
  免费   989篇
  国内免费   65篇
耳鼻咽喉   243篇
儿科学   489篇
妇产科学   338篇
基础医学   2513篇
口腔科学   299篇
临床医学   1545篇
内科学   3409篇
皮肤病学   519篇
神经病学   2395篇
特种医学   989篇
外科学   2336篇
综合类   124篇
一般理论   4篇
预防医学   872篇
眼科学   286篇
药学   941篇
中国医学   62篇
肿瘤学   1204篇
  2023年   136篇
  2022年   98篇
  2021年   432篇
  2020年   297篇
  2019年   415篇
  2018年   446篇
  2017年   404篇
  2016年   500篇
  2015年   497篇
  2014年   691篇
  2013年   826篇
  2012年   1337篇
  2011年   1414篇
  2010年   820篇
  2009年   709篇
  2008年   1173篇
  2007年   1163篇
  2006年   1106篇
  2005年   1091篇
  2004年   934篇
  2003年   882篇
  2002年   793篇
  2001年   154篇
  2000年   133篇
  1999年   181篇
  1998年   188篇
  1997年   136篇
  1996年   145篇
  1995年   99篇
  1994年   89篇
  1993年   72篇
  1992年   77篇
  1991年   76篇
  1990年   50篇
  1989年   41篇
  1988年   41篇
  1987年   38篇
  1986年   28篇
  1985年   32篇
  1984年   26篇
  1983年   27篇
  1982年   42篇
  1981年   26篇
  1980年   42篇
  1979年   28篇
  1978年   23篇
  1977年   34篇
  1976年   19篇
  1975年   19篇
  1965年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
In order to establish an univariate nonparametric pediatric tolerance region platelet function has been investigated in 105 healthy children and adolescents. In comparison to adult normal values, the bleeding time is shortened, spontaneous platelet aggregation is enhanced as well as collagen-induced platelet aggregation. 30% of the children showed an increased disaggregation in ADP-induced aggregation. A slight delay was found in the spreading of thrombocytes. Platelet volume shifted to the left. Values of beta-thromboglobulin were raised. Compared to adult values no alterations could be found in platelet shape-change. Changes of platelet functions were more apparent in the younger children.  相似文献   
62.
63.
64.
Long-term use of cyclosporine after renal transplantation results in nephrotoxicity and an increased cardiovascular risk profile. Tacrolimus may be more favorable in this respect. In this randomized controlled study in 124 renal transplant patients, the effects of conversion from cyclosporine to tacrolimus on renal function, cardiovascular risk factors, and perceived side-effects were investigated after a follow-up of 2 years. After conversion from cyclosporine to tacrolimus renal function remained stable, whereas continuation of cyclosporine was accompanied by a rise in serum creatinine from 142 +/- 48 micromol/L to 157 +/- 62 micromol/L (p < 0.05 comparing both groups). Conversion to tacrolimus resulted in a sustained reduction in systolic and diastolic blood pressure, and a sustained improvement in the serum lipid profile, leading to a reduction in the Framingham risk score from 5.7 +/- 4.3 to 4.8 +/- 5.3 (p < 0.05). Finally, conversion to tacrolimus resulted in decreased scores for occurrence of and distress due to side-effects. In conclusion, conversion from cyclosporine to tacrolimus in stable renal transplant patients is beneficial with respect to renal function, cardiovascular risk profile, and side-effects. Therefore, for most renal transplant patients tacrolimus will be the drug of choice when long-term treatment with a calcineurin inhibitor is indicated.  相似文献   
65.
Summary Two patients are described with the triad of tonic pupil, hyporeflexia and segmental anhidrosis (Ross syndrome). Only 18 cases of this syndrome have been reported in the literature so far. While tonic pupil and reduced sweating can be attributed to the affection of postganglionic cholinergic parasympathetic and sympathetic fibres projecting to the iris and sweat glands, respectively, the pathogenesis of diminished or lost tendon jerks remains obscure. To identify the characteristic clinical features, the previous cases of Ross syndrome are reviewed. Recent evidence of subclinical disturbances of sweating in most patients with Adie's syndrome, i.e. tonic pupil and areflexia, casts doubt on the nosological concept of Ross syndrome as a distinct clinical entity.  相似文献   
66.
We report on the hypothalamic-pituitary-gonadal function in 2 male infants with the Smith-Lemli-Opitz (SLO or RSH) syndrome. Both infants had abnormal external genitalia. Basal and LHRH stimulated plasma gonadotropins were normal for age (1 month). Plasma testosterone, androstenedione, and dehydroepiandrosterone sulfate were normal for age and sex. Some forms of congenital adrenal hyperplasia (17,20-desmolase deficiency, 17α-hydroxylase deficiency, and 3β-hydroxysteroid dehydrogenase deficiency) were ruled out by hormonal studies. The endocrinological findings indicate a normal hypothalamic-pituitary-gonadal function and a normal adrenal steroid biosynthesis in these 2 patients. A partial androgen receptor defect causing the genital malformations seems possible in one patient. Whether 5α-reductase deficiency is the cause of the male pseudohermaphroditism in SLO syndrome remains the subject of future studies. © 1992 Wiley-Liss, Inc.  相似文献   
67.
Limited efficacy of chemotherapy in most solid tumors has revived interest in immunotherapeutic approaches for cancer. One novel form of immunotherapy is the use of cancer vaccines consisting of tumor cells genetically engineered to secrete cytokines. The rationale for this immunization strategy is based on the existence of tumor-specific antigens, on the importance of the cellular arm of the immune system in mediating an effective antitumor response, and on the role of cytokines in regulating the cellular immune response. Such tumor vaccines showed considerable promise in various animal models and induced potent antitumor immunity in the host, which led to regression of established tumors and, moreover, produced immunological memory protecting animals from a subsequent tumor challenge at a distant site. Translated to the human patient, this implies that genetically modified tumor vaccines may be able to eradicate or reduce existing tumor deposits to subclinical levels as well as provide long-term protection from regrowth of tumor cells. This report will review and discuss the concept and rationale for the use of cytokine-secreting tumor vaccines for the treatment of human malignancies.  相似文献   
68.
Insulin-like growth factor 1 (IGF-1) is a potent mitogen for human breast-cancer cells in vitro. In circulation, most of IGF-1 is bound to IGF-binding protein 3 (IGFBP-3). This high-affinity binding is thought to have an important limiting effect on the availability of IGF-1 for biological activity. To assess the availability of IGF-1 for receptor binding, we determined serum levels of IGF-1 and IGFBP-3 and IGF-1/IGFBP-3 ratios. In a case-control study, 150 women aged 38 to 75 years presenting with stage-l or-II breast cancer were investigated just prior to surgery (n = 76), or to irradiation one month after surgery (n = 74). The population-based control group consisted of 441 women of the same age having no breast cancer. Women reporting diabetes mellitus or other hormonal abnormalities were excluded. Premenopausal cases showed elevated IGF-1 serum concentrations, decreased IGFBP-3 levels and increased IGF-1/IGFBP-3 ratios. The IGF-1/IGFBP-3 ratio was a significant breast-cancer risk factor, also after adjustment for age, family history, height, body-mass index, body-fat distribution, and serum levels of C-peptide. The relative risk was 7.34 for the highest compared with the lowest quintile of IGF-1/IGFBP-3. The presence or absence of tumor had no influence on these results. Increased levels of available IGF-1 in the circulation of pre-menopausal women may contribute to the development of breast cancer. © 1995 Wiley-Liss Inc.  相似文献   
69.
OBJECTIVE: Apathy is among the most frequent neuropsychiatric symptoms in dementia, particularly Alzheimer disease. The Apathy Evaluation Scale (AES) has been widely employed for assessing apathy in different patient groups. To further facilitate the usage of the AES, an abbreviated version was constructed. METHOD: On basis of a sample of 356 nursing home residents, a cross-validation procedure was carried out to develop a brief version of the AES. According to a thorough clinical examination, 85% of the residents were demented, 8% presented with mild cognitive impairment, whereas 7% did not present any cognitive deficits. After subdividing the patient group into two matched samples, the first subsample was used to identify problematic items due to defined psychometric and content-related criteria. The original 18-item scale was thus reduced to 10 items. Psychometric properties of the shortened version were subsequently reassessed in the second subsample. RESULTS: The short version demonstrated favorable psychometric properties that could be confirmed by cross-validation with the second sample. Correlations with the original full-length version were high (r = 0.97 for both subsamples); the shortened scale yielded no substantial losses regarding internal consistency or construct validity (correlations with the respective subscales of the Neuropsychiatric Inventory). CONCLUSION: The frequency of apathetic symptoms in the nursing home residents included confirms the clinical importance of apathy for understanding dementia. Given this specific patient population, setting, and mode of data collection, the short-version AES seems to be a valuable and time-efficient instrument for assessing apathy.  相似文献   
70.
Abstract Background and Purpose: The radiologic evaluation of musculoskeletal injuries in young children is difficult due to the absent ossification of several secondary ossification centers, which therefore cannot be seen directly on plain radiographs. When relying on conventional radiographs, even severe cartilaginous or soft tissue injuries cannot be visualized, as there is no possibility to differentiate them from bruises or sprains. It is the aim of this review to present clinically relevant applications of ultrasound imaging in pediatric musculoskeletal trauma. Methods: Currently used ultrasound techniques for evaluation of typical pediatric fractures or joint dislocations, techniques for differentiation between stable and unstable intraarticular fractures, the use of sonography for monitoring reduced bone length in long bones after fracture, sonographic guidelines for evaluation of tendon injuries or lesions, and sonographic imaging techniques in arthritis and osteomyelitis are described. Conclusion: Musculoskeletal sonography—despite its inability to view through intact cortical bone and its accuracy being dependent on skill and experience of the investigator—provides important information about soft tissue, bony or cartilaginous injuries in children.  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