全文获取类型
收费全文 | 6986篇 |
免费 | 280篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 132篇 |
妇产科学 | 61篇 |
基础医学 | 870篇 |
口腔科学 | 120篇 |
临床医学 | 464篇 |
内科学 | 1910篇 |
皮肤病学 | 68篇 |
神经病学 | 405篇 |
特种医学 | 348篇 |
外科学 | 1047篇 |
综合类 | 58篇 |
一般理论 | 2篇 |
预防医学 | 207篇 |
眼科学 | 184篇 |
药学 | 352篇 |
中国医学 | 11篇 |
肿瘤学 | 1052篇 |
出版年
2023年 | 45篇 |
2022年 | 92篇 |
2021年 | 159篇 |
2020年 | 85篇 |
2019年 | 121篇 |
2018年 | 138篇 |
2017年 | 111篇 |
2016年 | 154篇 |
2015年 | 145篇 |
2014年 | 229篇 |
2013年 | 314篇 |
2012年 | 486篇 |
2011年 | 512篇 |
2010年 | 275篇 |
2009年 | 235篇 |
2008年 | 441篇 |
2007年 | 476篇 |
2006年 | 437篇 |
2005年 | 436篇 |
2004年 | 417篇 |
2003年 | 402篇 |
2002年 | 431篇 |
2001年 | 80篇 |
2000年 | 44篇 |
1999年 | 86篇 |
1998年 | 105篇 |
1997年 | 87篇 |
1996年 | 103篇 |
1995年 | 68篇 |
1994年 | 54篇 |
1993年 | 66篇 |
1992年 | 49篇 |
1991年 | 45篇 |
1990年 | 51篇 |
1989年 | 55篇 |
1988年 | 66篇 |
1987年 | 34篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 18篇 |
1983年 | 28篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 6篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 9篇 |
1968年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有7323条查询结果,搜索用时 0 毫秒
41.
Orita S Hirose M Takahashi S Imaida K Ito N Shudo K Ohigashi H Murakami A Shirai T 《Toxicologic pathology》2004,32(2):250-257
Effects of dietary administration of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-3-hydroxy-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid (Re-80); 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido]benzoic acid (Am-580); and 6-[(3,5-di-tert-butylphenyl) carbamoyl]nicotinic acid (Am-55P) were examined using a two-stage rat carcinogenesis model. A total of 190 female SD rats was treated sequentially with 1,2-dimethylhydrazine (DMH, s.c.); 7,12-dimethylbenz(a)anthracene (DMBA, i.g.); and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN, in the drinking water) during the first three weeks (DDD-initiation), and an additional 60 rats received the vehicle alone (non-initiation). One week after the completion of the initiation period, they were divided into nine groups and administrated Re-80 (at dose levels of 1.0 or 0.4 ppm), Am-580 (20 or 4 ppm), Am-55P (20 ppm), ACA (100 ppm), all-trans-retinoic acid (10 or 2 ppm) or no supplement in the diet for 33 weeks, until survivors were euthanatized at week 37 weeks. After DDD-initiation, all-trans-retinoic acid at the high dose delayed the development of mammary tumors. The multiplicity of colon tumors in the group fed Am-55P and the incidences of nephroblastomas with ACA or Am-580 were decreased as compared with the control values, but the other chemicals had no modifying effects on tumor development in any organs. Thus, among ACA and the novel synthetic retinoids tested, only Am-55P showed a weak inhibitory effect on a neoplasm of general interest under the present experimental conditions. 相似文献
42.
K Maruoka M Yamanaka M Misago K Nakata J Tsukada K Nagata T Sato N Mori S Oda S Chiba 《Rinsho byori. The Japanese journal of clinical pathology》1990,38(10):1161-1166
The activities of RNase (RNase-U and RNase-C) were determined in the serum and leukocytes of 277 patients with 14 cases of various kinds of eosinophilia (not less than 10(3)/microliters), 28 cases of chronic myelocytic leukemia (CML), using polyuridylic acid and polycytidylic acid as synthetic substrates according to the method of Raddi et al. Serum RNase-U activity, serum RNase-C activity and the activity ratio (U/C x 10(-3)) were 55 +/- 14 U, 1,280 +/- 235 U and 44 +/- 11 (mean +/- SD), 196 +/- 137, 1,992 +/- 1,134 U and 97 +/- 38, and 110 +/- 50 U, 1,854 +/- 625 U and 65 +/- 13 for normal subjects, eosinophilia and CML (untreated), respectively. U/C ratio in eosinophilia and CML (untreated) showed a highly significant positive correlation (p less than 0.001) with peripheral eosinophil count; the activity of serum RNase-U per cells in the supernatant of eosinophil homogenate rose significantly (p less than 0.001) compared with that of lymphocytes or granulocytes. Besides, serum and eosinophil RNase-U had a similar optimal pH. These results suggested that serum RNase-U in eosinophilia originated mostly from eosinophils and its rise was correlated strongly with the increase in eosinophils. 相似文献
43.
Suppression of UV-induced mutations by wild-type p53 protein in human osteosarcoma cells 总被引:2,自引:0,他引:2
We have examined whether the tumour suppressor p53 protein suppressedUV-induced mutations in the hypoxathine-guanine phosphoribosyltransferase (HPRT) gene and in the supF gene of the shuttlevector plasmid pMY189. We used human osteosarcoma Saos-LP12cells, in which wild type (wt) p53 protein was induced by treatmentwith isopopyl-(ß-D-thiogalactopyranoside. The inductionof wt p53 protein suppressed UV-induced mutations but not spontaneousmutations in the HPRT gene. The frequency of UV-induced mutationsinduced by UV-irradiation of the plasmid was also significantlylower in cells with induced wt p53 protein than in the uninducedcells. In addition, we found that frequency of G : C to A :T transition mutations which occurred at the 3' base pair ofdipyrimidine sites were significantly lower in the cells withinduced wt p53 protein than in the uninduced cells. These findingssuggestthat wt p53 protein may play roles in modulating DNArepair pathway, resulting in the suppression of UV-induced mutations.
1To whom correspondence should be addressed 相似文献
44.
Noriaki Kameda Mineyuki Kagesawa Nobuyuki Hiruta Michio Akima Megumi Ohki Tsukasa Matsumoto 《Pathology international》1987,37(2):291-303
A 62-year-old female with primary leiomyosarcoma of the left femur is reported with a review of 21 cases reported in the literature. The resected specimen showed that the tumor extended from the femoral head to the diaphysis for 13cm in length. The tumor showed mainly intramedullary proliferation, but extraosseous growth was also noted at the great trochanter. Microscopic examination revealed well differentiated leiomyosarcoma characterized by interlacing bundles of fusiform cells with eosinophilic cytoplasm and rod-shaped hyperchromatic nuclei. PAP stain of actin on the tumor cells was positive. On electron microscopy, microfilament of 6–8 nm in diameter, dense bodies, plnocytotic vesicles, marginal attachment plate, and basal lamina were noted. The patient died with pulmonary metastasis, 1 year and 7 months after the operation. An autopsy showed metastases in the right pelvic cavity and bilateral lungs, and confirmed the primary site to be the left femur. 相似文献
45.
Lack of association between DNA base excision repair gene XRCC1 Gln399Arg polymorphism and risk of malignant lymphoma in Japan 总被引:2,自引:0,他引:2
Matsuo K Hamajima N Suzuki R Andoh M Nakamura S Seto M Morishimae Y Tajima K 《Cancer Genetics and Cytogenetics》2004,149(1):77-80
Growing evidence suggests that the polymorphism of DNA base excision repair gene XRCC1 Arg399Gln is associated with altered DNA repair proficiency and subsequent cancer susceptibility; however, no evidence is available for malignant lymphoma. We therefore conducted a case-control study (372 cases, 500 controls) to evaluate links with malignant lymphoma risk in Japan. The risk was evaluated in terms of odds ratio (OR) and 95% confidence interval (CI) adjusted for age and sex in an unconditional logistic regression model. There was no statistical risk change with the Arg/Gln (adjusted OR 0.89; 0.65-1.23, P = 0.492) or the Gln/Gln (0.57; 0.27-1.17, P = 0.127) compared with the Arg/Arg of the XRCC1 Arg399Gln polymorphism. The results were unchanged in analyses according to histological subtype (diffuse large lymphoma, follicular lymphoma, low-grade lymphoma of mucosa-associated lymphoid tissue, and others). These data suggest that XRCC1 Gln399Arg polymorphism plays a limited role in lymphomagenesis. Further study on the interaction between the polymorphism and environmental exposure is required. 相似文献
46.
Toshiaki Maruyama Ichiro Saito Sachiko Miyake Hiroshi Hashimoto Kazuto Sato Hideo Yagita Ko Okumura Nobuyuki Miyasaka 《European journal of immunology》1993,23(9):2059-2065
Synovial T cells play a crucial role in the pathogenesis of rheumatoid arthritis (RA) synovitis. We have quantitatively analyzed the T cell receptor (TcR) variable (V) region gene repertoire of freshly isolated synovial fluid (SF) T cells, comparing it with that of peripheral blood (PB) T cells in RA. The TcR V gene repertoire of PB and SF T cells in RA and osteoarthritis was heterogeneous. In contrast, Vail in SF was expressed to a greater degree in three of five RA patients, and increased levels of Vp6, 1-3 were found in the SF of four of six RA, compared with paired PB. Of note, Vβ6, 1–3 was universally used in four RA patients with a disease duration of less than 10 years, irrespective of their HLA-DR types. This was in contrast to two other RA patients, suffering for more than 20 years, who showed different Vα and Vβ usages. β-chain sequence analysis in RA patients with a preference for Vβ6, 1–3 has shown that a few clones dominated in SF, whereas polyclonality was observed in PB. These findings suggest oligoclonal expansion of T cells in response to specific antigen(s) in the SF of these patients with RA of relatively short duration. Concomitant use of two hydrophobic amino acids, leucine and valine, in the Dβ region was noticeable among the predominant SF clones. These two amino acids might directly contact a peptide specific for the induction of synovitis in RA patients. TcR-directed therapy may, therefore, be useful for the treatment of early RA synovitis. 相似文献
47.
Tomoyuki Shirai Michihito Takahashi Shoji Fukushima Nobuyuki Ito 《Pathology international》1985,35(1):35-43
Iodoacetamide (IAA), an ulcerogenic compound, was continuously given to male Wistar rats for up to 74 weeks. No carcinomas developed but marked glandular hyperplasias were frequently observed accompanied by chronic ulcer or erosion in the fundic region. They showed pseudo-invasive growth into the submucosa, the granulomatous tissue and even into the muscle layer, but no cellular and nuclear atypia was observed in their glands. Characteristically the mucosal damage caused by chronic IAA treatment was restricted to the fundic mucosa along the limiting ridge. Abnormally regenerated mucosa in the damaged area showed pyloric gland type metaplasia, demonstrated histo-chemically by paradoxical concanavalin A-staining and high-iron diamine-Alcian blue staining for mucin. No intestinal metaplasia was observed in these mucosa. 相似文献
48.
Motonobu Nishimura MD Takashi Nishimura MD Masayuki Ishikawa MD Ayumu Masuoka MD Nobuyuki Okamura MD Keiko Abe MD Takahiro Matsuoka MD Mika Iwazaki MD Kazuhito Imanaka MD Haruhiko Asano MD Shunei Kyo MD 《Journal of artificial organs》2006,9(4):209-213
The presence of a significant organ dysfunction does not immediately exclude patients from consideration for treatment with
a left ventricular assist system (LVAS). However, in treating morbid circulatory shock patients with multiple organ failure,
it is important to know the preoperative and postoperative factor or factors related to the recovery of the damaged organ
function. In this study, we retrospectively analyzed patients receiving a LVAS at our institution and tried to determine the
important factors related to the survival of patients with multisystem failure. Twenty-seven patients who underwent LVAS placement
at Saitama Medical School Hospital between 1993 and 2003 were included in this study. The preoperative risk factors analyzed
were renal dysfunction, respiratory dysfunction, hepatic dysfunction, the existence of active infection, and the combination
of all four factors. As a postoperative factor, the pump flow index (mean LVAS pump flow during the first 2 weeks after LVAS
surgery divided by the body surface area) was analyzed. None of the analyzed preoperative factors could predict survival after
LVAS surgery, but a pump flow index of less than 2.5 l/min/m2 had a significant relationship with death after LVAS surgery. Further analysis revealed that all the patients with a pump
flow index of 3.0 l/min/m2 or more could overcome preoperative organ dysfunction. Congestive heart failure patients with multisystem failure need luxury
pump flow for successful LVAS surgery; this factor could be especially important in device selection and postoperative management. 相似文献
49.
Summary The role of Ca channel and extracellular Ca2+ on autoregulation of renal blood flow was investigated in the perfused kidney of the anesthetized dog. The perfusion pressure was changed in the range between 60 and 200 mm Hg. Intra-arterial infusion of nifedipine (5 g/min) increased renal blood flow at a perfusion pressure above 100 mm Hg and inhibited autoregulation. Simultaneous infusion of 5 g/min of BAY K 8644 antagonized the effect of nifedipine. Renal blood flow was increased and autoregulatory relationship between flow and perfusion pressure was inhibited by EDTA (30 mg/min) infusion. The inhibitory effect of EDTA on renal autoregulation was counteracted by simultaneous infusion of CaCl2 at 30 mg/min, but not counteracted by that of BAY K 8644 (5 g/min). BAY K 8644 also could not antagonize the inhibitory effect of a vasodilator, papaverine (5 mg/min) on renal blood flow autoregulation. These results provide the evidence that the renal autoregulation involves the process of Ca2+ influx into the vascular smooth muscle cell through the Ca channels.
Send offprint requests to N. Ogawa at the above address 相似文献
50.
Summary To examine the role of Ca channels in autoregulation of renal blood flow in response to changes of perfusion pressure, experiments were performed with perfused kidney in anesthetized dogs using a Ca channel activator, BAY K 8644, and vasoconstrictors such as noradrenaline and angiotensin II. Control observations usually showed excellent autoregulation of renal blood flow at pressures between 120 and 200 mm Hg, the autoregulatory index being less than 0.2. Verapamil (50 g/min, i.a. infusion) obviously inhibited the renal autoregulation. Simultaneous infusion of 5 g/min of BAY K 8644 with verapamil prevented both the increase of renal blood flow and the impairment of the autoregulation caused by verapamil. Whereas simultaneous infusion of noradrenaline (1 and 3 g/min) or angiotensin 11 (0.1 and 0.3 g/min) with verapamil dose-dependently reduced renal blood flow, these drugs could not antagonize the inhibitory effect of verapamil on autoregulation. The present experiments show that Ca channels play an important role in establishing renal autoregulation, and that a mere vasoconstriction by noradrenaline and angiotensin II is distinguished from autoregulatory performance. 相似文献