全文获取类型
收费全文 | 11978篇 |
免费 | 580篇 |
国内免费 | 106篇 |
专业分类
耳鼻咽喉 | 153篇 |
儿科学 | 203篇 |
妇产科学 | 92篇 |
基础医学 | 1363篇 |
口腔科学 | 285篇 |
临床医学 | 711篇 |
内科学 | 3266篇 |
皮肤病学 | 198篇 |
神经病学 | 883篇 |
特种医学 | 410篇 |
外科学 | 1959篇 |
综合类 | 50篇 |
预防医学 | 283篇 |
眼科学 | 262篇 |
药学 | 771篇 |
中国医学 | 60篇 |
肿瘤学 | 1715篇 |
出版年
2023年 | 80篇 |
2022年 | 161篇 |
2021年 | 341篇 |
2020年 | 189篇 |
2019年 | 260篇 |
2018年 | 338篇 |
2017年 | 239篇 |
2016年 | 332篇 |
2015年 | 326篇 |
2014年 | 398篇 |
2013年 | 467篇 |
2012年 | 747篇 |
2011年 | 872篇 |
2010年 | 480篇 |
2009年 | 371篇 |
2008年 | 700篇 |
2007年 | 776篇 |
2006年 | 741篇 |
2005年 | 764篇 |
2004年 | 758篇 |
2003年 | 727篇 |
2002年 | 729篇 |
2001年 | 163篇 |
2000年 | 98篇 |
1999年 | 129篇 |
1998年 | 128篇 |
1997年 | 125篇 |
1996年 | 111篇 |
1995年 | 93篇 |
1994年 | 91篇 |
1993年 | 82篇 |
1992年 | 79篇 |
1991年 | 73篇 |
1990年 | 83篇 |
1989年 | 73篇 |
1988年 | 73篇 |
1987年 | 64篇 |
1986年 | 56篇 |
1985年 | 47篇 |
1984年 | 23篇 |
1983年 | 43篇 |
1982年 | 21篇 |
1981年 | 30篇 |
1980年 | 25篇 |
1979年 | 27篇 |
1978年 | 18篇 |
1977年 | 13篇 |
1975年 | 11篇 |
1974年 | 16篇 |
1972年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Hidetoshi Kawashima Toshiji Igarashi Yoshikage Nakajima Yasuhiro Akiyama Kazuyasu Usuki Shinzaburo Ohtake 《Naunyn-Schmiedeberg's archives of pharmacology》1978,305(2):123-126
Summary An intravenous injection of 40 or 65 mg/kg streptozotocin induced not only diabetes but also severe hypertension in rats. Whereas the hyperglycemia developed fully within a few days after the injection of streptozotocin, the hypertension progressively advanced and reached maximum level several weeks after the treatment and lasted more than 20 weeks. Twenty mg/kg streptozotocin did not induce hyperglycemia but significantly increased blood pressure several weeks after the treatment. Arrest of growth, polyuria, glycosuria, hyperlipemia and lenticular cataracts developed in the animals treated with 40 or 65 mg/kg streptozotocin, but in none of the animals treated with 20 mg/kg. In histological examinations in the 24th week after the treatment, degranulation and necrosis in the pancreatic -cells, and vacuolization and deposition of PAS-positive materials in the renal proximal tubules were found in the animals treated with 40 or 65 mg/kg streptozotocin. 相似文献
92.
Tetsuya Yamada Gaku Ichihara Hailan Wang Xiaozhong Yu Kei-ichiro Maeda Hiroko Tsukamura Michihiro Kamijima Tamie Nakajima Yasuhiro Takeuchi 《Toxicological sciences》2003,71(1):96-103
Although 1-bromopropane has been used in chemical and electronic industries as an alternative to ozone layer-depleting solvents, its toxicity on female reproductive organs has not been fully elucidated. The aim of this experiment was to determine the effect of 1-bromopropane on female reproductive function in rats. Forty female Wistar rats were divided into four equal groups. Each group was exposed daily to 0, 200, 400, or 800 ppm of 1-bromopropane for eight h a day. After exposure for 7 weeks, all rats in the 800-ppm group became seriously ill and were sacrificed during the 8th week. The other dose groups were exposed for 12 weeks. In the 800-ppm group, but not in the other two exposed groups, body weight was significantly less than the control at each time point from 2 to 7 weeks after the beginning of exposure. Tests of vaginal smears showed a significant increase in the number of irregular estrous cycles with extended diestrus in the 400- and 800-ppm groups. Histopathological examination of the ovary showed a significant dose-dependent reduction of the number of normal antral follicles and a decrease in the number of normal growing follicles in the 400-ppm group. No significant change was found in plasma concentrations of LH or FSH in any group when compared with the control. Our results indicate that 1-bromopropane can induce a dose-dependent ovarian dysfunction in nonpregnant female rats associated with disruption in follicular growth process. 相似文献
93.
Taro Semba Yasuhiro Funahashi Naoto Ono Yuji Yamamoto Naoko Hata Sugi Makoto Asada Kentaro Yoshimatsu Toshiaki Wakabayashi 《Clinical cancer research》2004,10(4):1430-1438
We reported previously that an angiogenesis inhibitor, E7820, inhibits in vitro tube formation of human umbilical vein endothelial cell through the suppression of integrin alpha2 expression. Here we describe the antiangiogenic and antitumor effects of E7820 in mice and discuss the feasibility of using platelet integrin alpha2 expression on platelets as a biological marker of the efficacy of E7820. Oral administration of E7820 significantly inhibited basic fibroblast growth factor-induced angiogenesis in Matrigel implants and human colon WiDr tumor-induced angiogenesis in a dorsal air sac model. Twice-daily treatment with E7820 clearly inhibited the s.c. tumor growth of seven tumor cell lines derived from human colon, breast, pancreas, and kidney, and completely suppressed the growth of human pancreatic KP-1 and human colon LoVo cell lines. Moreover, E7820 significantly inhibited the growth of KP-1 and human colon tumor Colo320DM cells orthotopically implanted in the pancreas and cecum, respectively. The efficacy of E7820 was comparable in the s.c. and orthotopic transplantation models. Immunohistochemical analyses using anti-CD31 antibody showed that E7820 significantly reduced microvessel density in orthotopically implanted KP-1 tumor. E7820 reduced integrin alpha2 expression on a megakaryocytic cell line, Dami cells, induced by phorbol 12-myristate 13-acetate treatment. It also decreased the expression level of integrin alpha2 on platelets withdrawn from mice bearing s.c. KP-1 tumor at a dosage close to that affording antitumor activity. These data demonstrate that E7820 showed a broad-spectrum antitumor effect in mice through inhibition of angiogenesis and indicate that the decrease of integrin alpha2 on platelets might serve as a biological marker for the antitumor efficacy of E7820. 相似文献
94.
95.
Liu N Ono T Suyama K Nogaki F Shirakawa K Maeda M Kawamura T Kamata T Oyama A Muso E Sasayama S 《Kidney international》2000,58(2):598-606
BACKGROUND: Factor V in its active form (Va) plays a key role at the termination of the intrinsic coagulation pathway, serving as a membrane-bound cofactor for the conversion of prothrombin to thrombin by factor Xa. Cross-linked fibrin (XFb) is often observed in mesangial areas in active types of human glomerulonephritis. In this study, to clarify contribution of factor V in intramesangial coagulation, mesangial factor V expression and its relationship to mesangial proliferation and fibrin deposition in IgA nephropathy (IgAN) were investigated. METHODS: Twenty-two patients with IgAN were studied. XFb was detected in renal biopsy specimens using anti-d-dimer antibody combined with plasmin exposure, and factor V was detected with rabbit antibody against human factor V. Double-labeling immunohistochemistry was used to investigate the relationship of the glomerular distribution of factor V to XFb. The relationship of factor V staining to the activity index or XFb deposition was evaluated. The expression of factor V mRNA was assessed by in situ hybridization in relationship to the antigen staining of alpha-smooth muscle actin (alpha-SMA). The ultrastructural distribution of factor V in glomeruli was studied by immunoelectron microscopy. RESULTS: XFb and factor V were observed in the mesangium and along capillary loops in seven and nine specimens, respectively. Factor V had intense, frequent expression in the proliferating and necrotizing areas, showing a significant relationship to XFb (P < 0.05). Furthermore, XFb deposition and factor V expression were markedly correlated with disease activity (P = 0.005 and P = 0.008, respectively). By double-labeling experiments, XFb and factor V were often seen colocalized in mesangial areas of the glomeruli, which showed necrotizing lesions and/or intense cellular proliferation. By in situ hybridization, factor V mRNA was detected mainly in the mesangial cells, which were positive for alpha-SMA, and partly in the endothelial cells. By immunoelectron microscopy, factor V presence was confirmed in the mesangium and endothelium. CONCLUSION: The present findings suggest that factor V is strongly expressed in mesangial cells in active IgAN accompanied with mesangial proliferation and may exert procoagulant activity, leading to intramesangial coagulation. 相似文献
96.
Yasuhiro Hamada Masahiro Mizoguchi Satoshi O. Suzuki Toru Iwaki 《Brain tumor pathology》1998,15(2):77-82
Following DNA damage, wild-type p53 increases and mediates the multiple cellular responses for the repair of DNA damage or
apoptosis. Inactivation of p53 by single-amino-acid substitutions contributes to the malignant phenotype and confers resistance
to therapy. Among tumor-derived p53 mutants, class I mutants still retain a native-like three-dimensional structure, whereas
class II mutants have unfolded DNA-binding domains. Sequencing analysis demonstrated that a human glioma cell line (U-373MG)
had only a class I mutant form of p53 of His273, which targets an Arg273 that contacts DNA but retains the native structure.
In this study, we investigated the metabolic alteration of the class I mutant p53 in apoptosis of U-373MG. The cell cycle
progression of U-373MG cells was affected by the addition of carboplatin, while the amount of mutant p53 also increased in
their nuclei. The treated cells underwent apoptosis 48h after exposure to 50 μg/ml carboplatin. Although the exact mechanism
of the class I mutant p53 in the process of apoptosis has not yet been clarified, the fact that accumulation of the activated
mutant p53 in the nucleus of U-373MG is concomitant with apoptosis, just as wild-type p53 does, implies that the class I mutant
p53 might retain the ability to participate in apoptosis. 相似文献
97.
98.
Norito Takamura Toru Maruyama Etsuo Chosa Keiichi Kawai Yasuhiro Tsutsumi Yukie Uryu Keishi Yamasaki Tsuneo Deguchi Masaki Otagiri 《Drug metabolism and disposition》2005,33(4):596-602
To determine whether bucolome (5-n-butyl-1-cyclohexyl-2,4,6-trioxoperhydropyrimidine), a nonsteroidal anti-inflammatory agent, can reverse diuretic resistance of furosemide in patients with nephrotic syndrome, we examined the inhibitory effect of bucolome on the protein binding of furosemide in serum and urine. Bucolome significantly inhibited the protein binding of furosemide not only in serum but also in urine of preparation albumin (UPA), which mimics urinary albumin concentration in patients with nephrotic syndrome by ultrafiltration method. The binding percentage of furosemide to albumin was approximately 70% in UPA. With coadministration of bucolome to healthy volunteers, renal clearance of furosemide was increased, reflecting the increase of the free fraction of furosemide in serum. Furthermore, coadministration of bucolome caused a significant increase of urine volume and sodium concentration in urine. Even at higher urine levels of furosemide, the inhibitory effect of bucolome on the protein binding of furosemide in UPA remains constant, and changes in pH at weakly acidic pH levels (pH 5.5-6.5) did not alter the inhibitory effect of bucolome. Interestingly, coadministration of bucolome with furosemide in doxorubicin (Adriamycin)-induced nephrotic syndrome model rats alleviated the diuretic resistance. These results suggest that bucolome has a potent inhibitory effect on the protein binding of furosemide in the urine and can partially restore the diuretic response of furosemide in patients with nephrotic syndrome by increasing the free fraction of furosemide at the site of action. 相似文献
99.
Sanae Fukuda Hiroki Ishikawa Yasuhiro Koga Yuji Aiba Kazuko Nakashima Lei Cheng Taro Shirakawa 《The Journal of adolescent health》2004,35(2):156-158
We studied 867 junior high school children and administered a questionnaire documenting allergic symptoms and environmental variables, and measured Immunoglobulin E serum levels and the immunoglobulin G titers of serum antibody to microflora. A total of 716 subjects were ultimately used for statistics; those with at least two of the following allergic symptoms: asthma, rhinitis, eczema, or food allergy, showed significantly higher IgG titers to Bactroides vulgatus than other groups. This finding suggests that a species of the Bacteroides genus of the intestinal microflora tends to affect the gut issues, but further studies are needed to clarify this. 相似文献
100.
To clarify the nature of serous retinal detachment in Vogt-Koyanagi-Harada (VKH) syndrome, 42 consecutive eyes of 21 patients with acute phase VKH syndrome were examined using optical coherence tomography (OCT). OCT revealed two patterns of serous retinal detachment. Twenty-nine eyes (69%) had a true retinal detachment, 17 eyes (40%) had intraretinal fluid accumulation in the outer retina, and 4 eyes had both. Intraretinal fluid accumulation appeared as an oval space in the outer retina. On fluorescein angiography, the eyes with intraretinal fluid accumulation showed more severe dye leakage from the retinal pigment epithelium. 相似文献