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   2169篇
  免费   85篇
  国内免费   6篇
耳鼻咽喉   6篇
儿科学   42篇
妇产科学   58篇
基础医学   300篇
口腔科学   39篇
临床医学   190篇
内科学   380篇
皮肤病学   15篇
神经病学   153篇
特种医学   204篇
外科学   327篇
综合类   22篇
预防医学   142篇
眼科学   28篇
药学   120篇
中国医学   1篇
肿瘤学   233篇
  2023年   12篇
  2022年   35篇
  2021年   44篇
  2020年   32篇
  2019年   29篇
  2018年   37篇
  2017年   25篇
  2016年   34篇
  2015年   28篇
  2014年   53篇
  2013年   58篇
  2012年   99篇
  2011年   102篇
  2010年   50篇
  2009年   35篇
  2008年   86篇
  2007年   108篇
  2006年   91篇
  2005年   90篇
  2004年   85篇
  2003年   79篇
  2002年   92篇
  2001年   77篇
  2000年   93篇
  1999年   85篇
  1998年   27篇
  1997年   25篇
  1996年   23篇
  1995年   10篇
  1994年   19篇
  1993年   14篇
  1992年   61篇
  1991年   44篇
  1990年   42篇
  1989年   45篇
  1988年   49篇
  1987年   45篇
  1986年   46篇
  1985年   45篇
  1984年   32篇
  1983年   28篇
  1982年   8篇
  1979年   16篇
  1977年   15篇
  1975年   7篇
  1973年   11篇
  1972年   8篇
  1971年   12篇
  1969年   7篇
  1968年   9篇
排序方式: 共有2260条查询结果,搜索用时 14 毫秒
101.
A 36-year-old man referred to our hospital with the chief complaint of painful left inguinal mass and fever. He had undergone left orchiopexy for undescended testis at 10 years of age. With the suspicion of an incarceration of inguinal hernia, an operation was performed. However, there was no hernia sac, and only swelling inguinal lymph nodes were found. Pathological diagnosis of the nodes was metastatic embryonal carcinoma, with suspicion of testicular origin. As scrotal ultrasonography revealed a hypoehcoic mass within the left atrophic testis, left high orchiectomy was performed. Pathological diagnosis of the left testicular mass was seminoma. A definite diagnosis was left testicular cancer, mixed type of seminoma and embryonal carcinoma, with inguinal nodes metastasis, pT1N2M0. He received 3 courses of bleomycin, etoposide, and cisplatin (BEP) chemotherapy, and there has been no sign of metastasis nor recurrence 18 months after the operation. To our knowledge, this is the 11th case in Japan of testicular cancer with inguinal node metastasis in a patient with prior orchiopexy for undescended testis.  相似文献   
102.
Summary The mechanism of artificial and spontaneous metastases of tumor was analyzed in B16 melanoma cells and C57BL/6 mice by using anti-asialo GM1 antibody and anticancer agents. Single administrations of 500 g anti-asialo GM1 antibody resulted in significantly decreased NK activity in spleen cells of C57BL/6 mice, lasting 10 days from the day following administration. Treatment with anti-asialo GM1 antibody never decreased the function of T lymphocytes measured by blastogenesis with phytohemagglutinin or T cell growth factor. The tumoricidal functions of activated macrophages but not of resident macrophages were decreased by in vivo treatment with anti-asialo GM1 antibody.The anti-asialo GM1 antibody was evaluated in terms of the enhancing effect on pulmonary metastases with regard to the timing of administration. Treatment with anti-asialo GM1 antibody 1 day before or on the day of tumor inoculation resulted in a substantial increase in the number of artificial pulmonary metastases. In the experimental system of spontaneous metastases, anti-asialo GM1 antibody most effectively increased the number of pulmonary metastases when administered 1–2 weeks before the removal of primary tumor, when the tumor cells are thought to be released into blood circulation from the primary site. In addition, accelerated growth of transplanted tumors at the primary site was observed in mice treated with anti-asialo GM1 antibody. These results strongly suggest that anti-asialo GM1 antibody enhances the incidence of in vivo tumor metastases and the growth of transplanted tumor mainly by suppressing the function of NK cells.The maximum effective dose (MED) of mitomycin C or its derivative (M-83) suppressed NK activity significantly, and pretreatment with these anticancer agents enhanced the growth of the artificial pulmonary and liver metastases. In contrast, the MED of cDDP showed no effect on the NK activity or the numbers of pulmonary and liver metastases. These results indicate that the depression of NK activity induced by chemotherapy results in the promotion of metastatic disease.From these studies it can be concluded that NK cells have a key role in the control of metastases of malignant disease, and that support of NK activity is very important for the prevention of metastases.  相似文献   
103.
A test of the mitogenic activity of greater than 40 purified and crude sources of hormones and growth factors revealed that epidermal growth factor, high density lipoprotein, an extract of bovine pituitary, hypothalamus, or whole brain, and the medium conditioned by differentiated human hepatoma cells were mitogenic for cultured endothelial cells derived from human umbilical vein. The four active agents combined with an improved nutrient medium and a collagen- or fibronectin-coated culture surface supported the growth of the endothelial cell population at a rate of 0.70-0.80 generations per day at both low and high cell densities in serum-free medium. The brain-derived activity exhibited properties reported by Maciag et al. [Maciag, T., Hoover, A. & Weinstein, R. (1982) J. Biol. Chem. 257, 5333-5336] and Gordon et al. [Gordon, P. B., Sussman, I. I. & Hatcher, V. B. (1983) In Vitro 19, 661-671]. The liver cell-derived activity was a specific product of differentiated hepatoma cells. The medium from HeLa cells, relatively undifferentiated rat liver cell lines, and human fibroblasts was inactive. Purified plasma proteins of liver origin could not substitute for the hepatoma cell-conditioned medium. The hepatoma cell-derived activity was non-dialyzable, heat-labile, stable between pH 4 to 11, inactivated by trypsin and mercaptoethanol treatment, and stable after treatment with 6 M urea and phenylmethylsulfonyl fluoride. The results provide a simplified model for elucidation of the endocrinology of human endothelial cell growth, function, and aging. We suggest an endocrine role of both the nervous system and liver in the regeneration of endothelial cells.  相似文献   
104.
We report three cases with methotrexate-vinblastin-adriamycin-cisplatin (MVAC) resistant multiple liver metastases of urothelial carcinoma that responded to combination chemotherapy consisting of gemcitabine plus carboplatin (GC) with additional docetaxel (GCD) as salvage chemotherapy. Case 1: A 55-year-old man underwent left nephroureterectomy for ureteral cancer (TCC, G3, pT3pN1M0). Three courses of GC followed by three courses of GCD were given via intra-hepatic arterial infusion for multiple liver metastases, which appeared after adjuvant high-dose MVAC therapy. Complete response was obtained and maintained for 11 months. Case 2: A 46-year-old man underwent radical cystectomy for locally advanced bladder cancer (TCC G3 + adenocarcinoma. pT3pN0M0). Two courses of GC followed by 2 courses of GCD systemic therapies were performed for multiple liver metastases, which appeared after adjuvant high-dose MVAC therapy. Partial response was obtained and maintained for six months. Case 3: A 66-year-old man received three courses of MVAC for multiple metastases of the bladder cancer (TCC, G3, > pT2), which resulted in disease progression. Eight courses of GC followed by six courses of GCD were administrated via intra-hepatic arterial infusion. Partial response was obtained and maintained for 12 months. Although the response duration was still short, GC and GCD may be promising salvage chemotherapeutic regimens for the patients with MVAC-resistant liver metastases of urothelial carcinoma.  相似文献   
105.
Morphological analyses in and around the epiphyseal cartilage of mice deficient in insulin receptor substrate-1 (IRS-1) showed IRS-1 signaling to be important for skeletal growth by preventing early closure of the epiphyseal cartilage and maintaining the subsequent bone turnover at the primary spongiosa. Introduction: IRS-1 is an essential molecule for intracellular signaling by IGF-I and insulin, both of which are potent anabolic regulators of cartilage and bone metabolism. To clarify the role of IRS-1 signaling in the skeletal growth, morphological analyses were performed in and around the epiphyseal cartilage of mice deficient in IRS-1 (IRS-1(-/-)), whose limbs and trunk were 20-30% shorter than wildtype (WT) mice. MATERIALS AND METHODS: The epiphyseal cartilage and the primary spongiosa at proximal tibias of homozygous IRS-1(-/-) and WT male littermates were compared using histological, immunohistochemical, enzyme cytohistochemical, ultrastructural, and bone histomorphometrical analyses. RESULTS: In and around the WT epiphyseal cartilage, IRS-1 and insulin-like growth factor (IGF)-1 receptors were widely expressed, whereas IRS-2 was weakly localized in bone cells. Chronological observation revealed that height of the proliferative zone and the size of hypertrophic chondrocytes were decreased in WT mice as a function of age, and these decreases were accelerated in the IRS-1 (-/-) cartilage, whose findings at 12 weeks were similar to those of WT at 24 weeks. In the IRS-1(-/-) cartilage, proliferating chondrocytes with positive proliferating cell nuclear antigen (PCNA) or parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor immunostaining had almost disappeared by 12 weeks. Contrarily, TUNEL+ apoptotic cells were increased in the hypertrophic zone, at the bottom of which most of the chondrocytes were surrounded by the calcified matrix, suggesting the closure of the cartilage. In the primary spongiosa, bone volume, alkaline phosphatase (ALP)+ osteoblasts, TRACP+ osteoclasts, and the osteopontin-positive cement line were markedly decreased. Bone histomorphometrical parameters for both bone formation and resorption were significantly lower in IRS-1(-/-) mice, indicating the suppression of bone turnover. CONCLUSION: The IRS-1(-/-) epiphyseal cartilage exhibited insufficient proliferation of chondrocytes, calcification of hypertrophic chondrocytes, acceleration of apoptosis, and early closure of the growth plate. Thus, the data strongly suggest that IRS-1 signaling is important for the skeletal growth by preventing early closure of the epiphyseal cartilage and by maintaining the subsequent bone turnover at the primary spongiosa.  相似文献   
106.
107.
Gallium scintigraphy was evaluated in 25 patients with adult T-cell leukemia lymphoma (ATLL). Anterior and posterior images were obtained at 72 h after administration of 3 mCi 67Ga-citrate using a gamma camera (Maxi-Camera 400T, General Electric Co.) with a medium energy standard parallel hole collimator. Abnormally high accumulations were observed in 17 out of 25 cases (superficial lymph node, 8; hilar and mediastinal lymph node, 7; paraaortic lymph node, 2; lung, 9; liver, 1; bone, 1). There were 10 malignant lesions detected by 67Ga scintigraphy in 9 out of 17 cases (superficial lymph node, 1; hilar and mediastinal lymph node, 6; paraaortic lymph node, 1; liver, 1; bone, 1). White blood cell count and serum LDH levels were raised in patients with abnormally high accumulations of 67Ga. In conclusion, 67Ga scintigraphy seemed to be a useful examination to detect malignant lesions in patients with ATLL.  相似文献   
108.
A set of monochorionic male twins presented with intestinal perforation. The smaller twin was diagnosed with necrotizing enterocolitis followed by sepsis, disseminated intravascular coagulation, and necrotizing fasciitis of the abdominal wall. The infant died on the fourth day after surgery, 16 days after birth. Surgical specimens and autopsy revealed a disseminated zygomycotic infection. Gastrointestinal zygomycosis followed by necrotizing fasciitis in premature infants is a rare condition and mimics necrotizing enterocolitis clinically. Necrotizing fasciitis after gastrointestinal zygomycosis in premature infants is considered a poor prognostic sign. Gastrointestinal zygomycosis should be considered in the differential diagnosis of necrotizing enterocolitis.  相似文献   
109.
The presence of Ca2+- and voltage-activated K+ channels was directly demonstrated in the apical cell membrane of gallbladder epithelium by patch-clamp single-channel current recording. In K+-depolarized epithelial cells, negative pipette potentials induced outward current steps when the patch-pipette was filled with Na+-rich solution and these current steps were not affected by the presence or absence of Cl. When K+-rich solution was in the pipette and K+-depolarized cells were examined, the current-voltage relations were linear with a single-channel conductance of 140 pS and polarity was reversed at 0 mV. In excised inside-out membrane patches, raising the free Ca2+ concentration of the medium facing the inner side of the membrane from 10–7 to 10–6 M evoked a marked increase in open state probability of the channels without affecting the elementary current steps. This suggests that intracellular Ca2+ as a second messenger plays a crucial role in the regulatory mechanism of the membrane potential by modulating the high-conductance apical K+ channels.  相似文献   
110.
A 37-year-old female was indicated to have a non-mass lesion in her left breast on ultrasonography (US) and visited our outpatient clinic. Mammography showed no findings of masses or microcalcification. Dynamic magnetic resonance imaging (MRI) showed a segmental enhanced lesion consisting of nodular and ring enhancement. A US-assisted vacuumed needle biopsy was performed, and the histological findings revealed sclerosing adenosis and apocrine metaplasia. After 1 year of follow-up, the MRI findings suggested both a benign lesion and ductal carcinoma in situ, and surgical excision was performed. We used a new device to evaluate the surgical margin on MRI. The non-mass lesion was excised according to the device-guided margin under local anesthesia. The histological findings revealed the features of mastopathy. Following excision, MRI showed no residual non-mass lesions, and the shape of the patient’s left breast was maintained.  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