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   1558篇
  免费   78篇
  国内免费   12篇
耳鼻咽喉   11篇
儿科学   135篇
妇产科学   76篇
基础医学   171篇
口腔科学   18篇
临床医学   118篇
内科学   217篇
皮肤病学   53篇
神经病学   175篇
特种医学   106篇
外科学   249篇
综合类   25篇
一般理论   1篇
预防医学   54篇
眼科学   64篇
药学   104篇
中国医学   1篇
肿瘤学   70篇
  2021年   47篇
  2020年   19篇
  2019年   34篇
  2018年   50篇
  2017年   23篇
  2016年   28篇
  2015年   37篇
  2014年   42篇
  2013年   48篇
  2012年   80篇
  2011年   77篇
  2010年   49篇
  2009年   35篇
  2008年   65篇
  2007年   58篇
  2006年   54篇
  2005年   44篇
  2004年   58篇
  2003年   52篇
  2002年   51篇
  2001年   40篇
  2000年   39篇
  1999年   35篇
  1997年   21篇
  1996年   15篇
  1995年   20篇
  1994年   22篇
  1993年   13篇
  1992年   16篇
  1991年   32篇
  1990年   23篇
  1989年   17篇
  1988年   24篇
  1987年   26篇
  1986年   25篇
  1985年   22篇
  1984年   17篇
  1983年   18篇
  1982年   14篇
  1981年   19篇
  1980年   14篇
  1979年   20篇
  1978年   16篇
  1977年   15篇
  1974年   14篇
  1973年   13篇
  1972年   13篇
  1968年   18篇
  1967年   16篇
  1966年   16篇
排序方式: 共有1648条查询结果,搜索用时 15 毫秒
81.
82.
A 69-year-old man who had a left pneumonectomy for nonsmall cell lung cancer had a bronchopulmonary fistula develop that recurred after surgical closure. He had multiple organ failure develop precluding further operative intervention. Successful resolution of the fistula was achieved using a novel application of a covered expandable metallic stent.  相似文献   
83.
Although there have been reports on the effects of adrenal and pineal gland secretions on the hypothalamus and the pituitary, the maintenance of rhythmicity by these glands has not been reported so far. The present data deals with the alterations in the periodicity of hypothalamo-pituitary axis after the surgical removal of either adrenal, gonad or pineal in adult male rats. The data indicated an alteration in the 24 hour pattern of hypothalamic content of LHRH after adrenalectomy, castration or pinealectomy. In adrenalectomy group, the in vitro responsiveness of pituitary decreased at 0600 h and 100 h as compared to the intact rats, resulting in a low amplitude of LH circadian rhythm. The pituitaries of pinealectomized rats showed increased sensitivity at 1000 h and 1800 h which resulted in two peak LH concentration at those time intervals. Further, pinealectomized rats showed a selective five fold increase over 24 hr in serum FSH concentration as compared to intact rats suggesting dissociation in the release of FSH and LH.  相似文献   
84.
Inhibin activity in charcoal-extracted spent culture medium of Sertoli cells in Primary culture (CSCCM) was monitored by following the temporal inhibition of serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in normal adult male rats. Subcutaneous injection of CSCCM reduced LH and FSH levels within 15 min and maintained the inhibition up to 10 hr. No selective suppression of FSH was observed. The model was used to assess inhibin activity in CSCCM from Sertoli cell cultures incubated with 5 alpha-dihydrotestosterone (DHT), testosterone (T), and estradiol -17 beta (E2) (5 micrograms/ml) for 24 hr. CSCCM from T and E2 treated groups suppressed gonadotropins while the group exposed to DHT failed to elicit any inhibition. DHT seems to inhibit the release of inhibin by Sertoli Cells.  相似文献   
85.
BACKGROUND AND AIMS: Topical glucocorticoid formulations are widely used for effective treatment and control of a variety of dermatoses. Mometasone furoate is a newer corticoid that has high potency but low systemic toxicity. Pharmaceutical factors are known to significantly influence potency and systemic absorption of topically applied glucocorticoids. We studied the potency of "Elocon", a topical formulation of mometasone furoate, compared with two other branded formulations of the same corticoid. METHODS: Corticoid potency was measured by employing a pharmacodynamic parameter of an inhibitory effect of the corticoid on post-ischemic-reactive-hyperemic-response (PIRHR) in human forearm skin under occlusive dressing. The PIRHR was expressed in terms of % increase in the skin blood flow (SBF) as measured with laser doppler velocimetry (LDV). RESULTS : All three active branded formulations of mometasone furoate produced significant inhibition of PIRHR. The AUC(0-2 min) of PIRHR was ( Mean +/- SEM ), Control = 213.52 +/- 11.80, Placebo = 209.77 +/- 19.31, Formulation A = 119.83 +/- 13.71, Formulation C = 53.67 +/- 4.85 and Formulation D = 111.46 +/- 22.87. Formulation "C" exhibited significantly higher topical anti-inflammatory potency than formulations "A" or "D". CONCLUSIONS: Thus, branded formulations of the same glucocorticoid, mometasone furoate significantly differed in their topical anti-inflammatory potency. "Elocon" was significantly more potent than the two other branded formulations studied.  相似文献   
86.
87.
88.
During early development, the eutherian mammalian embryo forms a blastocyst comprising an outer trophectoderm epithelium and enclosed inner cell mass (ICM). The short-term goal of blastocyst morphogenesis, including epithelial differentiation and segregation of the ICM, is mainly regulated autonomously and comprises a combination of temporally controlled gene expression, cell polarisation, differentiative cell divisions and cell-cell interactions. This aspect of blastocyst biogenesis is reviewed, focusing, in particular, on the maturation and role of cell adhesion systems. Early embryos are also sensitive to their environment, which can affect their developmental potential in diverse ways and may lead to long-term consequences relating to fetal or postnatal growth and physiology. Some current concepts of embryo-environment interactions, which may impact on future health, are also reviewed.  相似文献   
89.
Nayer H  Weir EG  Sheth S  Ali SZ 《Cancer》2004,102(5):315-321
BACKGROUND: Primary pancreatic lymphomas (PPL) are extremely rare. Clinically, PPL usually present with symptoms of carcinoma of the pancreatic head. An accurate cytopathologic diagnosis by fine-needle aspiration (FNA) is imperative because the primary treatment is nonsurgical, based on a combination of chemotherapy and radiation therapy. METHODS: Eight cases of PPL were identified from the pathology files of The Johns Hopkins Hospital over a 14-year period (1989-2003). All cases were diagnosed on FNA performed under radiologic guidance. Needle rinses were used to perform flow cytometric (FC) analysis. No tissue studies were performed after the FNA diagnosis was made. RESULTS: A strong male predominance (male-to-female ratio of 7:1) was noted. The patients ranged in age from 35-75 years (mean age, 55 years). The tumors varied in size from 2-14 cm, as evaluated on the radiologic scans (mean dimension of 8.0 cm). Abdominal pain was the most common presenting symptom (six patients) followed by jaundice, acute pancreatitis, small bowel obstruction, and diarrhea. The cytomorphologic features included hypercellularity with discohesive cells with round nuclei, often prominent nucleoli, mitoses, and karyorrhexis. By FC analysis, all eight cases demonstrated a monoclonal pattern of immunoglobulin light chain expression. The patients were treated with either chemotherapy alone or in conjunction with radiation therapy or stem cell transplantation. CONCLUSIONS: PPL is an extremely rare pathologic entity. FNA coupled with FC analysis appears to be highly accurate in the diagnosis of PPL and is the sole diagnostic modality used clinically. Based on cytomorphology, the main differential diagnoses of PPL involve secondary lymphoma, pancreatic endocrine neoplasm, and florid chronic pancreatitis. An accurate FNA diagnosis of PPL is critical for timely, nonsurgical management and obviates the need for an exploratory laparotomy.  相似文献   
90.
Novel treatment of chronic severe hand dermatitis with bexarotene gel   总被引:6,自引:0,他引:6  
BACKGROUND: Hand dermatitis is an eczematous inflammation of the hands that is related to occupation or to routine activities. It often becomes chronic, and in some patients may become severe and disabling. Topical corticosteroids are effective treatment, particularly for milder forms, but they often lose effectiveness with time and can produce skin atrophy. OBJECTIVES: To evaluate bexarotene gel topical therapy for safety, tolerability and efficacy in patients with chronic hand dermatitis. METHODS: A phase I-II open-label randomized clinical study of bexarotene gel, alone and in combination with a low- and a mid-potency steroid, was conducted in 55 patients with chronic severe hand dermatitis at two academic clinics. RESULTS: Patients using bexarotene gel monotherapy reached a 79% response rate for > or = 50% clinical improvement and a 39% response rate for > or = 90% clearance of hands. Adverse events possibly related to treatment in all patients were stinging or burning (15%), flare of dermatitis (16%) and irritation (29%). Thirteen patients (24%) withdrew early, including two for related adverse events and five for inadequate response. CONCLUSIONS: Bexarotene gel appears to be safe, tolerated by most patients, with useful therapeutic activity in chronic severe hand dermatitis.  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