全文获取类型
收费全文 | 11803篇 |
免费 | 603篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 267篇 |
妇产科学 | 108篇 |
基础医学 | 1705篇 |
口腔科学 | 297篇 |
临床医学 | 709篇 |
内科学 | 3023篇 |
皮肤病学 | 156篇 |
神经病学 | 951篇 |
特种医学 | 501篇 |
外科学 | 2115篇 |
综合类 | 37篇 |
预防医学 | 319篇 |
眼科学 | 195篇 |
药学 | 772篇 |
中国医学 | 29篇 |
肿瘤学 | 1218篇 |
出版年
2023年 | 60篇 |
2022年 | 98篇 |
2021年 | 207篇 |
2020年 | 105篇 |
2019年 | 159篇 |
2018年 | 182篇 |
2017年 | 174篇 |
2016年 | 226篇 |
2015年 | 256篇 |
2014年 | 285篇 |
2013年 | 331篇 |
2012年 | 540篇 |
2011年 | 628篇 |
2010年 | 325篇 |
2009年 | 353篇 |
2008年 | 563篇 |
2007年 | 686篇 |
2006年 | 620篇 |
2005年 | 669篇 |
2004年 | 665篇 |
2003年 | 694篇 |
2002年 | 627篇 |
2001年 | 303篇 |
2000年 | 264篇 |
1999年 | 298篇 |
1998年 | 197篇 |
1997年 | 165篇 |
1996年 | 174篇 |
1995年 | 153篇 |
1994年 | 131篇 |
1993年 | 114篇 |
1992年 | 191篇 |
1991年 | 176篇 |
1990年 | 172篇 |
1989年 | 167篇 |
1988年 | 146篇 |
1987年 | 112篇 |
1986年 | 130篇 |
1985年 | 119篇 |
1984年 | 102篇 |
1983年 | 85篇 |
1982年 | 59篇 |
1981年 | 60篇 |
1980年 | 54篇 |
1979年 | 68篇 |
1978年 | 59篇 |
1977年 | 43篇 |
1974年 | 51篇 |
1973年 | 54篇 |
1967年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
951.
952.
Oda Y Miyajima K Kawaguchi K Tamiya S Oshiro Y Hachitanda Y Oya M Iwamoto Y Tsuneyoshi M 《The American journal of surgical pathology》2001,25(8):1030-1038
Pleomorphic leiomyosarcoma (PLMS) was recently described as a morphologic variant of leiomyosarcoma; however, its diagnostic criteria, as shown by morphologic features and biologic behavior, remain controversial. We describe 28 cases of pleomorphic sarcoma with pleomorphic areas in more than two thirds of the tumor and an ordinary leiomyosarcomatous fascicular area covering less than one third as PLMS. PLMS comprised 8.6% of all the leiomyosarcomas (322 cases) registered in our institute. Patients ranged in age from 31 to 89 years (average, 57.9 years). Seventeen patients (60.7%) were male and 11 were female. Tumor location was as follows: the extremities in 17 cases, the retroperitoneum or abdominal cavity in 7 cases, the chest/abdominal wall in 3 cases, and the scalp in 1 case. Histologically, all cases showed at least small foci of fascicles consisting of smooth muscle tumor cells, in addition to pleomorphic areas mimicking storiform-pleomorphic malignant fibrous histiocytoma. The border between pleomorphic and leiomyosarcomatous fascicular areas was sharp in 3 cases, gradual in 2 cases, and blending in 23 cases. Sixteen cases (57.1%) showed a typical storiform pattern, 6 cases revealed extensive stromal hyalinization, 6 cases showed a chronic inflammatory infiltrate, 2 cases had the foci of foamy xanthomatous cells, and 7 cases contained myxoid malignant fibrous histiocytoma-like areas covering less than 50% of the tumor. The tumors had a tendency to be of a morphologically higher grade (10 tumors were French Federation of Cancer Centers grade 2, 18 were grade 3). Five of 28 cases (18%) showed rhabdoid features. Immunohistochemically, all of the 28 tumors examined showed a positive reactivity for at least one smooth muscle marker (desmin, muscle-specific actin, and alpha-smooth muscle actin) in the leiomyosarcomatous fascicular areas. In the pleomorphic areas the expression of smooth muscle markers (desmin 10 of 28, muscle-specific actin 13 of 28, and alpha-smooth muscle actin 14 of 28) was significantly reduced, compared with that in leiomyosarcomatous fascicular area (desmin 18 of 28, muscle-specific actin 26 of 28, and alpha-smooth muscle actin 24 of 28). No significant difference was observed between the MIB-1 labeling index in the leiomyosarcomatous fascicular areas (26.10 on average) and that in the pleomorphic areas (26.17 on average). However, the MIB-1 labeling index in PLMS was significantly higher than that in ordinary leiomyosarcoma (n = 20, 12.86 on average) or storiform-pleomorphic malignant fibrous histiocytoma (n = 16, 16.63 on average). In 23 patients follow-up data were available with a duration of 1-239 months. Eleven patients developed metastases, and lung accounted for the most common site of metastasis (9 cases). Fifteen of 23 patients (65.2%) died of disease. Our results indicate that PLMS should be differentiated from ordinary leiomyosarcoma because of its high proliferative activities and rather aggressive biologic behavior. 相似文献
953.
H Kashima J Tanemura T Hasegawa E Oda T Muramatsu T Kusunoki 《Dementia and geriatric cognitive disorders》2001,12(5):326-339
A cognitive test comprising 27 subscales was administered to 262 demented patients and 92 normal subjects. Principal factor analysis followed by varimax and Harris-Kaiser rotation and Guttman's scalogram analysis was performed. The analysis yielded three factors, i.e. "recent memory", "immediate memory or attention" and "remote memory". The relationships between the three-dimensional distribution of the scores and the DSM-IIIR grade of dementia indicated the existence of a continuum of dementia severity. Scalogram analysis showed unidimensionality in the difficulty level of the subscales as well as in the severity of the cases. Thus, the simple summary score can be used as a good measure of the severity of dementia. 相似文献
954.
Thermodynamic and kinetic analyses of biomolecular interactions reveal details of the energetic and dynamic features of molecular recognition processes, and complement structural analyses of the free and complexed conformations. The recent improvements in both isothermal titration calorimetry and surface plasmon resonance sensoring provide powerful tools for analysing biomolecular interactions in thermodynamic and kinetic approaches. The thermodynamic and kinetic parameters obtained for binding between protein and DNA indicate the mechanism of specific DNA recognition, in the high-resolution structures of the protein-DNA complexes. The effects of temperature and ionic strength reflect the conformational changes of the protein and DNA molecules upon complex formation, including important contributions of water and solutes. When combined with mutational studies, the interactions can be reduced to several energetic contributions from individual contacts. These studies should be useful to determine general features of protein functions in genetic regulation. 相似文献
955.
956.
Use of 5-FU plus hyperbaric oxygen for treating malignant tumors: evaluation of antitumor effect and measurement of 5-FU in individual organs 总被引:8,自引:0,他引:8
Takiguchi N Saito N Nunomura M Kouda K Oda K Furuyama N Nakajima N 《Cancer chemotherapy and pharmacology》2001,47(1):11-14
PURPOSE: Hyperbaric oxygen (HBO) has been shown to increase tumor radiosensitivity. Several reports indicate that it also increases sensitivity to alkylating agents, but other reports suggest that it may speed angiogenesis and tumor growth. To throw light on these questions, we investigated the effects of HBO and 5-fluorouracil (5-FU), individually and in combination, on Sarcoma 180 implants in mice. METHODS: We administered 5-FU at a dose of 0.75 mg/mouse six times per week and HBO at 2 atm absolute pressure for 90 min six times per week, both 17 times in total. In combination treatment, HBO was administered immediately after 5-FU injection. RESULTS: Over the treatment period, tumor diameter increased 277.8% in the untreated control group, 244.1% in the group receiving HBO monotherapy, 182.7% in the group receiving 5-FU monotherapy, and 138.5% in the group receiving combination therapy. Concomitant HBO increased accumulation of 5-FU in the tumors, liver, and kidneys, but not in the brain, of recipient animals. CONCLUSIONS: Based on the above results, we conclude that concomitant HBO enhances the effects of 5-FU. 相似文献
957.
Hormonal therapy for endometrial adenocarcinoma 总被引:1,自引:0,他引:1
Recently, the number of cases of endometrial cancer has increased in Japan. Most of the increase are accounted for by premenopausal cases, which are frequently positive for ER or PR. Hormonal treatment using progestins such as MPA has been widely applied to endometrial cancer patients under 40 years old under the conditions of grade 1 well-differentiated endometrioid adenocarcinoma without myometrial invasion. In our hospital, we applied high-dose (600 mg/day) MPA for over 8 weeks in 14 cases of endometrial cancer, of which adenocarcinoma disappeared in 12 cases (86%), followed by cyclic administrations of low-dose MPA, with 7 subsequent recurrences. We think that a protocol for improving ovarian function, such as active induction of ovulation, should be established to induce intrinsic progesterone sufficient for the prevention of the recurrence of endometrial cancers. In the 2 cases, in which adenocarcinoma remained even after long administrations of MPA, myometrial invasion was noted in the surgically resected specimens. For advanced or recurrent endometrial cancers, MPA has been reported to be effective in an average of 26% in several reports, and effective in 42% cases when applied with combination chemotherapy, such as CAP, by virtue of the "chemical modulator" effect, which can delay the acquired resistance against ADM or CDDP. Furthermore, MPA has resulted in a significant improvement of 5-year disease-free survival rate when used as adjuvant therapy after complete operations and whole pelvic irradiation, compared with administrations of 5-FU in a randomized controlled study in Japan. Thus, in the future, we consider that hormonal therapy will play a more important role in endometrial cancer treatment. 相似文献
958.
Respiratory uptake was investigated for 10 polar organic solvents with high blood/air partition coefficients (lambda(blood/air)): ethyl acetate (lambda(blood/air), 77), methyl iso-butyl ketone (90), methyl acetate (90), methyl propyl ketone (150), acetone (245), iso-pentyl alcohol (381), iso-propyl alcohol (848), methyl alcohol (2590), ethylene glycol monobutyl ether (EGBE, 7970), and propylene glycol monomethyl ether (PGME, 12380). Test-air concentrations (Cinh) were 25 to 200 ppm. Four healthy male volunteers inhaled the test air for 10 min at rest and then room air for 5 min. The percentage of solvent in the end-exhaled air and in the mixed-exhaled air increased after the start of the test-air respiration, and reached a quasi-steady-state level within a few min. The speeds of these increases at the start of the test-air respiration became lower as lambda(blood/air) increased. The mean uptakes (U) for the last five min of the test air respiration were 67.3, 52.9, 60.4, 53.0, 52.6, 63.0, 60.3, 60.8, 79.7, and 81.3%, respectively, for ethyl acetate, methyl iso-butyl ketone, methyl acetate, methyl propyl ketone, acetone, iso-pentyl alcohol, iso-propyl alcohol, methyl alcohol, EGBE and PGME. Thus, U values of the alcohols were higher than those of the ketones and lower than the glycol ethers. The overall view, except for esters, showed that U increased with lambda(water/air) increases. This tendency can be explained by a hypothesis that solvent absorbed in the mucus layer of the respiratory tract is removed by the bronchial blood circulation. U values of ethyl acetate and methyl acetate were higher than those of methyl iso-butyl ketone and methyl propyl ketone, though the lambda(blood/air) values of these esters were nearly equal to those of the ketones. For the respiration of the esters, their metabolites, ethyl alcohol and methyl alcohol, were detected in the exhaled air. The exhalation percentage of the metabolites increased after the start of test-air respiration and reached a quasi-steady-state level of 2 and 3%, respectively, by the 5th min. These data suggest that removal of the solvent via metabolism in the wall tissue of the respiratory tract plays an important role for the esters. 相似文献
959.
T Oda 《Japanese journal of cancer research》1999,90(10):1051-1060
The study of human hepatitis, particularly in Asia, where the incidence rate has been the highest in the world, has contributed greatly to the understanding of carcinogenesis of the liver and related diseases. In this article, the history of research on hepatitis viruses and hepatocellular carcinoma (HCC) and the successful prevention of vertical transmission of hepatitis B virus (HBV) in Japan are reviewed, focusing on the studies that resulted in the identification of vertical transmission of HBV infection and the association of HBV-sustained infection and HCC. The vaccination trials for preventing HBV vertical transmission and the fruitful outcome of the nationwide vaccination strategy in Japan, on the basis of "selective" immunization by using anti-HBs immunoglobulin (HBIG) and HB vaccine, are highlighted. Ongoing studies on the mechanisms underlying hepatocarcinogenesis induced by viruses, e.g., the roles of viral proteins and inflammation, are also reviewed, and prospects for the control of HCC are discussed. 相似文献
960.
T Shimada E M Gillam Y Oda F Tsumura T R Sutter F P Guengerich K Inoue 《Chemical research in toxicology》1999,12(7):623-629
Recombinant human enzymes expressed in membranes obtained from Escherichia coli transformed with cytochrome P450 (P450) and NADPH-P450 reductase cDNAs were used to identify the human P450 enzymes that are most active in catalyzing the oxidative transformation of benzo[a]pyrene in vitro. Activation of benzo[a]pyrene to genotoxic products that cause induction of umu gene expression in Salmonella typhimurium NM2009 by P450 1A1 and P450 1B1 enzymes was found to be enhanced by inclusion of purified epoxide hydrolase (isolated from rat or human livers) with the reaction mixture. High-performance liquid chromatographic analysis showed that P450 1B1 catalyzed benzo[a]pyrene to trans-7, 8-dihydroxy-7,8-dihydrobenzo[a]pyrene at level of approximately 3 nmol min(-)(1) nmol of P450(-)(1) only when epoxide hydrolase was present and P450 1A1 (with the hydrolase) was able to catalyze benzo[a]pyrene at one-tenth of the activity catalyzed by P450 1B1. Kinetic analysis showed that ratio of V(max) to K(m) for the formation of trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene in this assay system was 3.2-fold higher in CYP1B1 than in CYP1A1. Other human P450s (including P450s 1A2, 2E1, and 3A4) were found to have very low or undetectable activities toward the formation of trans-7, 8-dihydroxy-7,8-dihydrobenzo[a]pyrene. A reconstituted system containing purified P450 1B1, rabbit liver NADPH-P450 reductase, and human liver epoxide hydrolase was found to catalyze benzo[a]pyrene to trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene at a rate of 0.86 nmol min(-)(1) nmol of P450(-)(1); the activities were found to be largely dependent on the presence of sodium cholate in the system. These results suggest that P450 1B1 is a principal enzyme in catalyzing the oxidation of benzo[a]pyrene to trans-7,8-dihydroxy-7, 8-dihydrobenzo[a]pyrene and that the catalytic functions of P450 1B1 may determine the susceptibilities of individuals to benzo[a]pyrene carcinogenesis. 相似文献