全文获取类型
收费全文 | 35120篇 |
免费 | 1665篇 |
国内免费 | 137篇 |
专业分类
耳鼻咽喉 | 486篇 |
儿科学 | 670篇 |
妇产科学 | 406篇 |
基础医学 | 4364篇 |
口腔科学 | 1127篇 |
临床医学 | 2450篇 |
内科学 | 7863篇 |
皮肤病学 | 760篇 |
神经病学 | 3350篇 |
特种医学 | 1806篇 |
外国民族医学 | 1篇 |
外科学 | 5408篇 |
综合类 | 125篇 |
一般理论 | 6篇 |
预防医学 | 1107篇 |
眼科学 | 744篇 |
药学 | 2260篇 |
中国医学 | 71篇 |
肿瘤学 | 3918篇 |
出版年
2023年 | 182篇 |
2022年 | 331篇 |
2021年 | 581篇 |
2020年 | 345篇 |
2019年 | 439篇 |
2018年 | 566篇 |
2017年 | 478篇 |
2016年 | 602篇 |
2015年 | 572篇 |
2014年 | 746篇 |
2013年 | 921篇 |
2012年 | 1533篇 |
2011年 | 1561篇 |
2010年 | 953篇 |
2009年 | 804篇 |
2008年 | 1418篇 |
2007年 | 1652篇 |
2006年 | 1514篇 |
2005年 | 1454篇 |
2004年 | 1475篇 |
2003年 | 1378篇 |
2002年 | 1435篇 |
2001年 | 1309篇 |
2000年 | 1421篇 |
1999年 | 1271篇 |
1998年 | 467篇 |
1997年 | 382篇 |
1996年 | 361篇 |
1995年 | 300篇 |
1994年 | 300篇 |
1993年 | 275篇 |
1992年 | 988篇 |
1991年 | 848篇 |
1990年 | 811篇 |
1989年 | 802篇 |
1988年 | 758篇 |
1987年 | 755篇 |
1986年 | 667篇 |
1985年 | 621篇 |
1984年 | 423篇 |
1983年 | 343篇 |
1979年 | 296篇 |
1978年 | 199篇 |
1977年 | 177篇 |
1974年 | 188篇 |
1973年 | 162篇 |
1972年 | 161篇 |
1971年 | 181篇 |
1970年 | 155篇 |
1969年 | 176篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Jiro Okochi Kenji Toba Tai Takahashi Kozo Matsubayashi Masanori Nishinaga Ryutaro Takahashi Takashi Ohrui 《Geriatrics & Gerontology International》2006,6(4):223-227
Background: The aim of this study is to construct a simple screening test for the risk of falls in community-dwelling elder persons.
Methods: A total of 1378 community-dwelling people aged 65 years and older in five different communities in Japan were asked to answer a self rated questionnaire including 22 items covering physical, cognitive, emotional and social aspects of functioning and environmental factors. At a six-month follow-up, the outcome of fall occurrence and the number of falls was ascertained by social workers, health visitors or nurses.
Results: Five out of 22 items were selected using a logistic regression model. Using this five-item version, a screening test was constructed, and at the best cut-off point, the sensitivity and specificity were 68% and 70%, respectively. The validity of this scale was tested on persons with cognitive dysfunction.
Conclusion: The simplicity and the predictive validity of the screening test support the use of this test in health check ups or general outpatient facilities. 相似文献
Methods: A total of 1378 community-dwelling people aged 65 years and older in five different communities in Japan were asked to answer a self rated questionnaire including 22 items covering physical, cognitive, emotional and social aspects of functioning and environmental factors. At a six-month follow-up, the outcome of fall occurrence and the number of falls was ascertained by social workers, health visitors or nurses.
Results: Five out of 22 items were selected using a logistic regression model. Using this five-item version, a screening test was constructed, and at the best cut-off point, the sensitivity and specificity were 68% and 70%, respectively. The validity of this scale was tested on persons with cognitive dysfunction.
Conclusion: The simplicity and the predictive validity of the screening test support the use of this test in health check ups or general outpatient facilities. 相似文献
132.
Toshiji Ishiwata Ryo Koyama Noriyuki Homma Mitsuhiro Fujii Naoko Iwakami Yuta Nakao Shin-ichiro Iwakami Kazuhisa Takahashi 《Nihon Kokyūki Gakkai zasshi》2006,44(10):749-753
A 28-year-old man complaining of myiodesopsia was given a diagnosis of uveitis. Subsequently he complained facial nerve palsy and enlargement of parotid gland. Heerfordt's syndrome was diagnosed based on the results of several examinations. Facial nerve palsy, enlargement of the parotid gland and uveitis were improved by systemic corticosteroid therapy. At present he is receiving systemic corticosteroid therapy, but numbness in the mouth, thought to be the involvement of the trigeminal nerve, remains. Systemic corticosteroid therapy is usually effective for most cases with Heerford's syndrome. On the other hand, there are some cases with the prolonged peripheral nerve involvement despite systemic corticosteroid therapy, as seen in this case. If peripheral nerve involvement is prolonged, it is necessary to consider small-fibre neuropathy as one possible cause. 相似文献
133.
Sho Haneda M.D. Kouhei Fukushima M.D. Yuji Funayama M.D. Chikashi Shibata M.D. Ken-Ichi Takahashi M.D. Hitoshi Ogawa M.D. Munenori Nagao M.D. Kazuhiro Watanabe M.D. Iwao Sasaki M.D. 《Journal of gastrointestinal surgery》2006,10(7):1051-1059
Our previous studies demonstrated that sodium glucose cotransporter 1 (SGLT-1) was induced in the remnant ileum of total colectomized
rats via the action of factors other than hyperaldosteronism. The aim of the present study was to clarify whether fecal stream
is required for the enhancement of SGLT-1-mediated sodium transport. Twenty-seven pairs of ileal tissues were obtained from
the proximal and distal side, respectively, of loop ileostomy after total proctocolectomy. Mucosae were mounted in an Ussing
chamber to evaluate glucose-coupled sodium transport. Levels of SGLT-1 mRNA in proximal and distal mucosae were compared by
Northern blotting. Villous height and crypt depth were measured to test for correlations between mucosal structure and SGLT-1-mediated
sodium transport or mRNA expression levels. Both glucose-coupled sodium transport and expression of SGLT-1 mRNA were significantly
lower in distal mucosae relative to proximal mucosae. In distal mucosae, villous height, but not crypt depth, was significantly
lower than in proximal mucosae, demonstrating a positive correlation between villous height and SGLT-1 function and expression.
Comparative studies of proximal and distal mucosae demonstrated that in addition to hormonal changes, fecal stream is required
for full induction of the sodium transport system (which includes SGLT-1-mediated transport) in the remnant ileum following
total proctocolectomy.
Presented in part at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois,
May 14–19, 2005 (poster presentation).
This work was supported by Grants-in-Aid for Scientific Research 10557118 and 14657295 from the Ministry of Education, Science
and Culture of Japan to K. Fukushima, and by Kanae Foundation to K. Fukushima. 相似文献
134.
M Kuriyama Y Hokezu S Togo K Nagata K Takahashi T Igakura M Osame 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1992,29(7-8):559-564
Serum lipid, lipoprotein, apolipoprotein, and sterol profiles were studied in 22 patients with senile dementia of the Alzheimer type (SDAT) and 29 patients with vascular dementia (VD). Levels of high density lipoprotein-cholesterol (HDL-C) were lower in both patients groups of SDAT and VD than in control group. Apolipoprotein AI and AII are two major proteins in HDL. In this study, apolipoprotein AI levels were normal, but apolipoprotein AII levels were lower in the patient groups, especially in the VD group, than in the control group. Lipoprotein(a) levels were higher in both patient groups, especially in the VD group. There were no differences of cholesterol, cholesterol precursors (desmosterol and lathosterol), and plant sterols (campesterol and beta-sitosterol) among the three groups. Murine apolipoprotein AII is a serum precursor of murine senile amyloid protein, and the apolipoprotein AII variant with proline-->glutamine substitution at position 5 in the serum of accelerated senescence-prone mice is identical to the murine senile amyloid fibril protein from amyloid-deposited tissues of these mice. In human SDAT and VD, the reason for the low level of apolipoprotein AII remains unclear. 相似文献
135.
N Uemura K Ozawa A Tojo K Takahashi A Okano H Karasuyama K Tani S Asano 《Blood》1992,80(12):3198-3204
Since the ras family of proto-oncogenes is supposed to be involved in leukemogenesis by point-mutational activation, we studied the effect of the activated ras gene on the growth of a murine interleukin-3 (IL-3)-dependent cell line, FDC-P2. The human activated c-H-ras gene was transfected into FDC-P2 cells by electroporation using a high-level expression vector, BMGhph, which contains a partial DNA sequence from bovine papillomavirus (BPV) and a hygromycin B (hmB)-resistant gene as a selectable marker. The transformed FDC-P2 cells showed a high incidence of IL-3-independent growth and tumorigenicity in nude mice. These clones did not express or secrete IL-3, suggesting the acquisition of IL-3 independence by a nonautocrine mechanism. The high incidence of autonomous growth may be due to the use of the BMG vector, because (1) the activated ras gene in pBR322 vector (pHs-49) was not so efficient in the induction of IL-3 independence, (2) the c-H-ras genome copies per cell increased in number up to about 50 copies by using the BMG vector, and (3) cotransfection with the activated ras gene and the BPV gene in separate plasmids partly enhanced the incidence of autonomous growth without increasing the copy number of the ras gene compared with transfection with the activated ras gene alone. The present study supports the idea that the activation of ras gene is an important step in malignant transformation of hematopoietic cells and suggests that the BPV gene products may cooperate with ras gene activation probably by affecting the cellular genes that may be involved in multistep leukemogenesis. The BMG vector may be useful to test the transforming ability of oncogenes whose oncogenic potential is relatively low. 相似文献
136.
137.
S Miyakoshi H Haruyama T Shioiri S Takahashi A Torikata M Yamazaki 《The Journal of antibiotics》1992,45(3):394-399
Biosynthesis of griseolic acids, competitive inhibitors of cyclic nucleotide phosphodiesterase, was investigated with the culture of a producing strain of Streptomyces griseoaurantiacus. 13C-Labeled and 15N-labeled compounds were added into the culture, and 13C-enriched and 15N-enriched griseolic acid A was isolated from the culture medium and analyzed by 13C NMR and 15N NMR spectroscopy. The compounds added to growth medium were [2-13C]acetate, [1,2-13C]acetate, [1,4-13C]succinate, [1-13C]glucose, [6-13C]glucose, [2-13C]ribose, and [1-13C, 15N]glycine. The results suggest that adenosine, which is formed from amino acids and sugars contributes the adenine and ribose moieties to griseolic acid A. The data also suggest that a dicarboxylic acid from the Krebs tricarboxylic acid cycle contributes to the dicarboxylic part of the compound. 相似文献
138.
E Abe Y Ishimi N Takahashi T Akatsu H Ozawa H Yamana S Yoshiki T Suda 《Journal of bone and mineral research》1988,3(6):635-645
We have reported that the differentiation-inducing factor (DIF) is present in conditioned medium of mouse osteoblast-like cell (MC3T3-E1) cultures. In the present study, the DIF from conditioned medium of MC3T3-E1 cells was partially purified and its biologic activity was examined. The DIF was purified by monitoring the induction of phagocytic activity of mouse myeloblastic leukemia cells (M1). The DIF induced differentiation of not only M1 cells but also mouse myelomonocytic cells (WEHI-3). Furthermore, the DIF increased the in vitro bone-resorbing activity and the osteoclast number in mouse calvaria. The increases were inhibited by the addition of either salmon calcitonin or indomethacin. When mouse bone marrow cells were cultured with the DIF for 8 days, formation of osteoclast-like multinucleated cells was stimulated dose dependently. The DIF from MC3T3-E1 cells appeared to be different from interleukin-1 (IL-1), tumor necrosis factor (TNF), and transforming growth factor beta (TGF-beta). These results suggest that the DIF partially purified from osteoblast-like cell cultures stimulates osteoclastic bone resorption by promoting differentiation and fusion of osteoclast progenitors to form multinucleated osteoclasts. 相似文献
139.
T Takahashi 《Nihon Geka Gakkai zasshi》1988,89(4):494-507
The changes of cellular protein spots in human stomach carcinomas (Exp 4, H-111) and colon carcinomas (SW403, SW480) implanted into nude mice were examined after administration of MMC. The results were as follows. 1) Exp4 histologically showed pleomorphism after treatment by MMC. In other tumors no changes in histological features were shown. 2) The most remarkable decreases of p protein spots in Exp4, and moderate decreases of protein spots in SW403 and SW480 were admitted, contrasting to no changes in the pattern of protein spots in H-111. 3) The decreases of protein spots in the tumors were related to the sensitivities to MMC. 4) Regrowth tumors in Exp4 which were survived after administration of MMC revealed similar protein spots patterns and histological features to those in control tumors. 5) The changes in protein spots in the liver and kidney derived from normal mice were also examined. In these, protein spots patterns showed no changes after administration of MMC. These results suggest that the cellular protein sports were decreased in accordance with effect of MMC in the tumors. 相似文献
140.
Summary An esthesioneuroblastoma in a 16-year-old male was studied ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate-limiting enzyme in the catecholamine-synthesizing pathway. Tumor cells were fairly uniform in appearance, showing scantly cosinophilic cytoplasm and round to oval hyperchromatic nuclei, and were arranged in nests and cords of various sizes. Ultrastructurally, individual tumor cells had well-developed cell organelles including polyribosomes, microtubules, intermediate filaments, centrioles, Golgi apparatus and mitochondria. Secretory-like granules were occasionally found, predominantly in the cell processes. Immunohistochemically, many tumor cells were shown to be immunoreactive for TH. This finding strongly suggested that the present tumor was capable of producing catecholamines and that it might be derived from certain sympathetic neuronal cell nests in the superior nasal cavity. 相似文献