全文获取类型
收费全文 | 4891篇 |
免费 | 187篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 86篇 |
妇产科学 | 67篇 |
基础医学 | 634篇 |
口腔科学 | 63篇 |
临床医学 | 274篇 |
内科学 | 1204篇 |
皮肤病学 | 47篇 |
神经病学 | 440篇 |
特种医学 | 195篇 |
外科学 | 978篇 |
综合类 | 27篇 |
预防医学 | 91篇 |
眼科学 | 183篇 |
药学 | 252篇 |
中国医学 | 8篇 |
肿瘤学 | 536篇 |
出版年
2023年 | 21篇 |
2022年 | 50篇 |
2021年 | 105篇 |
2020年 | 44篇 |
2019年 | 67篇 |
2018年 | 78篇 |
2017年 | 66篇 |
2016年 | 99篇 |
2015年 | 101篇 |
2014年 | 139篇 |
2013年 | 182篇 |
2012年 | 293篇 |
2011年 | 314篇 |
2010年 | 147篇 |
2009年 | 133篇 |
2008年 | 265篇 |
2007年 | 299篇 |
2006年 | 266篇 |
2005年 | 297篇 |
2004年 | 300篇 |
2003年 | 297篇 |
2002年 | 303篇 |
2001年 | 70篇 |
2000年 | 71篇 |
1999年 | 90篇 |
1998年 | 63篇 |
1997年 | 66篇 |
1996年 | 64篇 |
1995年 | 60篇 |
1994年 | 62篇 |
1993年 | 68篇 |
1992年 | 45篇 |
1991年 | 45篇 |
1990年 | 36篇 |
1989年 | 39篇 |
1988年 | 30篇 |
1987年 | 24篇 |
1986年 | 41篇 |
1985年 | 34篇 |
1984年 | 31篇 |
1983年 | 34篇 |
1982年 | 22篇 |
1981年 | 29篇 |
1980年 | 23篇 |
1979年 | 25篇 |
1978年 | 20篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1974年 | 15篇 |
1971年 | 14篇 |
排序方式: 共有5116条查询结果,搜索用时 15 毫秒
71.
Antiarrhythmic effect and its underlying ionic mechanism of 17beta-estradiol in cardiac myocytes. 总被引:3,自引:0,他引:3
T Nakajima K Iwasawa H Oonuma T Morita A Goto Y Wang H Hazama 《British journal of pharmacology》1999,127(2):429-440
1. The effects of oestrogens on action potential and membrane currents were examined in single guinea-pig atrial myocytes. 2. 17Beta-estradiol (3-10 microM) shortened the action potential duration without significant changes in the resting membrane potential. E-4031 (1 microM) markedly prolonged the action potential duration and induced early afterdepolarization, and 17beta-estradiol (10 microM) abolished it. 3. When cells were perfused in isoproterenol-containing solution, action potentials due to abnormal automaticity caused by membrane depolarization developed, and were also inhibited by 17beta-estradiol. 4. Under voltage clamp conditions, the voltage-dependent Ca2+ currents consisted of both T-(I(Ca,T)) and L-type (I(Ca,L)). 17Beta-estradiol reduced I(Ca,L) concentration-dependently, while it (10 microM) suppressed I(Ca,T) only by approximately 10%. 17Beta-estradiol did not affect time courses of I(Ca,L) inactivation, but it shifted the steady-state inactivation curve to more negative potentials. 5. 17Beta-estradiol (10 microM) did not affect the time-dependent K+ current (I(K)), referred to as I(Kr) and I(Ks) and inwardly rectifying K+ current. However, 17beta-estradiol (30 microM) or diethylstilbestrol (10 microM) inhibited K+ currents. 6. DES and ethinylestradiol (EES) also suppressed I(Ca,L), but testosterone and progesterone failed to inhibit I(Ca,L) The potency of the inhibitory effect on I(Ca,L) was DES> EES> 17beta-estradiol. 7. 17Beta-estradiol and DES also inhibited the cyclic AMP-enhanced I(Ca,L), but cyclic GMP in the pipette or pretreatment of L-NAME could not block the effects of oestrogen on I(Ca,L). 8 These results suggest that oestrogen specifically has antiarrhythmic effects, possibly by acting the L-type Ca2+ channels. The antiarrhythmic effects of oestrogens may contribute to the cardioprotective actions of oestrogens. 相似文献
72.
Nobushige Yamashita Shiro Hoshida Kinya Otsu Naoyuki Taniguchi Tsunehiko Kuzuya Masatsugu Hori 《British journal of pharmacology》1999,128(2):412-418
1 We utilized a rat model of myocardial infarction to investigate whether cardioprotection by monophosphoryl lipid A (MLA) is provided in the early and late phases, as well as to determine whether this cardioprotection may be related to the activation of manganese superoxide dismutase (Mn-SOD), an intrinsic radical scavenger. 2 Pretreatment with MLA (0.5 or 1.0 mg kg-1, i.v.) 24 h prior to 20-min left coronary artery (LCA) occlusion and 48-h reperfusion significantly decreased the incidence of ventricular fibrillation (VF) during ischaemia, as well as infarct size. Pretreatment with lower concentrations of MLA, however, was ineffective. 3 When we examined the time course of MLA (0.5 mg kg-1)-induced cardioprotection, both infarct size and the incidence of VF were significantly reduced in rats pretreated with MLA 0.5 h and 24 h before occlusion. We observed no differences, however, 2 and 72 h after MLA treatment. 4 The activity of Mn-SOD paralleled the cardioprotective effects of MLA. Mn-SOD activity in the myocardium was significantly enhanced in rats pretreated with MLA (0.5 mg kg-1) 0.5 and 24 h before. Mn-SOD activity was not altered, however, in rats pretreated 2 or 72 h before. Lower MLA concentrations were not effective even 24 h after the treatment. 5 We conclude that MLA treatment induced a biphasic pattern of cardioprotection. The pattern of Mn-SOD activity suggests that this enzyme may play a major role in the acquisition of cardioprotection against ischaemia-reperfusion injury. 相似文献
73.
N Matsumoto T Tsuchida H Nakamura R Sawa Y Takahashi H Naganawa H Iinuma T Sawa T Takeuchi M Shiro 《The Journal of antibiotics》1999,52(3):276-280
The absolute structure of a new antibiotic lactonamycin is described. The NMR studies deduced one of four possible structures for the aglycon attached by a rhodinose through glycosidic bond. The stereochemistry of the sugar obtained by an acid hydrolysis was determined to be L-form by measuring optical rotation. The stereochemistry of the aglycon was determined by X-ray crystallographic analysis. 相似文献
74.
Hideki Horita M.D. Eiichi Hoashi M.D. Yuko Okuyama M.D. Koumei Kumagai M.D. Shiro Endo M.D. 《Psychiatry and clinical neurosciences》1977,31(3):393-402
We observed the attacks of nystagmus in a case of infantile spasms and carried out overnight sleep polygraphy. The following findings were obtained:
- 1 Awake time was prolonged to 56% of TIB, while sleep time was markedly shortened to 44% of TIB. Also REM sleep time was reduced to 20% of SPT and deep slow sleep (stage N3) was absent.
- 2 Attacks of nystagmus were observed only during wakefulness. At first, fast wave bursts appeared in the right occipital area, and were followed by left-upward deviations of eyeballs, and then the attacks of counterclockwise right-downward rotatory nystagmus. Also the fast wave bursts were succeeded by spreading of fast waves to adjacent areas. At the same time, EMG exhibited elevated muscle action potentials of mentalis and biceps fernoris. During the attacks of nystagmus, there was alteration of respiratory movements.
75.
In order to clarify the interaction of volatile anesthetics and extracellular calcium ion on the myocardial contraction, effects of both isoflurane (1.0%) and halothane (0.5%) on the extracellular calcium ion concentration ([Ca2+]O)-tension curve were studied. Increasing [Ca2+]O enhanced the myocardial contraction response, and the maximal response was obtained at [Ca2+]O of 3.0mM. Halothane depressed the maximal value of the tension development in response to increasing [Ca2+]O, while isoflurane did not (P 0.01). The probit response of the developed tension to the changes in [Ca2+]O indicated that isoflurane increased the median effective concentration (EC50) of [Ca2+]O significantly from 0.484 ± 0.051 (mean ± SEM) to 0.870 ± 0.056mM (P = 0.001), but halothane did not (P = 0.018). Therefore, 1.0% isoflurane was concluded to move the [Ca2+]O-tension curve to the right, while a downwards shift occurred with 0.5% halothane.(Saeki S, Hirakawa M, Shimosato S: Effects of Isoflurane and Halothane on the Calcium Ion-tension Curve in Rat Myocardium. J Anesth 6: 172–175, 1992) 相似文献
76.
Manabe Y Shiro Y Warita H Hayashi T Nakashima H Abe K 《Journal of the neurological sciences》2000,178(2):163-166
This is the first report of a patient with venous insufficiency following compressive arachnoiditis ossificans (AO). Symptoms of fluctuating monoplegia and sensory disturbance appeared monthly, lasting several weeks each time. Spinal magnetic resonance imaging (MRI) showed high T2-weighted signal intensity in the posterior portion of the column from T11 to T12 and an intradural lesion with low T2-weighted signal intensity. Neurological function and MRI improved markedly following an operation on AO. The symptoms seen in the present case were due to posterior venous insufficiency following compressive AO. 相似文献
77.
78.
Kazushige Kiguchi Masao Iwamori Yukari Mochizuki Takeshi Kishikawa Katsumi Tsukazaki Masahiko Saga Akira Amemiya Shiro Nozawa 《Cancer science》1998,89(9):923-932
Cells of the human tumor cell line RMG-1, derived from a clear-cell adenocarcinoma of the ovary, were injected intraperitoneally into nude mice, and the cells obtained from the tumor nodules in the mesenterium were found to form a larger number of, and larger-sized, tumor nodules than the original RMG-1 cells. The RMG-1-h cells, transferred into culture from the tumor nodules after a 4th in vivo passage, showed a dissemination potential as high as that of cells disseminating directly from the tissues, and exceedingly higher than that of RMG-1 cells. To assess the molecular bases of the different biological properties of RMG-1 and RMG-1-h cells, we compared the content and expression of various carbohydrate antigens in both cells. The chromosomal profile of RMG-1-h cells revealed their human origin and was identical to that of the original RMG-1 cells. In contrast to the broad histogram for the Lex-bearing cells among RMG-1 cells in flow cytometry, the weakly and moderately positive cells toward anti-Lex antibody were found to be eliminated from the histogram for the RMG-1-h cells, resulting in the enrichment of cells strongly expressing Lex, which may account for the high dissemination potential. In addition, the adhesion of RMG-1 cells to mesothelial cells was found to be significantly inhibited by pretreatment of the cells with anti-Lex antibody, indicating Lex-mediated cell-to-cell interaction between ovarian cancer cells and mesothelial cells. By TLC-immunostaining, two Lex-glycolipids, III3Fucα-nLc4Cer and V3Fucα-nLc6Cer were detected in both RMG-1 and RMG-1-h cells, and their total concentrations were not significantly different from each other. However, the hydrophobic moieties of Lex-glycolipids in RMG-1-h cells were different from those in RMG-1 cells, suggesting that a difference in the structure of the hydrophobic moieties of Lex is partly involved in the enhanced reactivity of RMG-1-h cells toward anti-Lex antibody. Thus, the high dissemination potential of ovarian cancer cells was shown to be mediated by the Lex-determinant and the Lex-bearing cells are enriched by repeated in vivo passage of the cells into nude mice. 相似文献
79.
Nawa Y Imaizumi H Masuda Y Hazama K Sato M Namiki A Asai Y 《Masui. The Japanese journal of anesthesiology》2000,49(9):1027-1029
A 15 year old female with uterus bicornis bicollis was admitted for operation. She had a history of atopic dermatitis and allergy to buckwheat, raw egg and latex. Two months previously she had developed whole body flushing during dental treatment, and latex glove used by the dentist had been suspected as the cause. Prior to the operation she underwent internal examination and intrauterine echogram in which a latex glove was carelessly used by another gynecologist who had not confirmed her past history. After 30 minutes, dyspnea and urticaria without itching, appeared suddenly. Blood pressure decreased to 80/50 mmHg and heart rate increased to 120 beats.min-1. She was then transferred to our ICU. Methylprednisolone was administered intravenously for dyspnea and circulatory collapse. After 3 hours, the patient made an uneventful recovery. The increased plasma latex protein-specific IgE levels confirmed anaphylaxis to latex. The increasing incidence of potentially life-threatening allergic reactions to latex has caused mounting concern over recent years. We may suspect latex allergy when an anaphylaxic reaction or shock of unknown origin occurs. In hospitals, latex free products must be prepared for use with latex allergic patients and for protection of medical staff with this allergy. 相似文献
80.
Satoshi Okayama M.D. Yoko Dote M.D. Yukiji Takeda M.D. Shiro Uemura M.D. Shinichi Fujimoto M.D. Ph.D. Yoshihiko Saito M.D. Ph.D. 《Echocardiography (Mount Kisco, N.Y.)》2013,30(1):E13-E15
A 63‐year‐old man was referred to our hospital because of a cardiac tumor. Transthoracic echocardiography revealed a rough, mobile tumor in the dilated right atrium, and transesophageal echocardiography showed that the tumor consisted of small, botryoidal masses. Catheter‐based biopsy carried a high risk of embolism. Therefore, we used F‐18‐fluorodeoxyglucose positron emission tomography (FDG‐PET), which revealed an abnormal accumulation in the right cervical lymph nodes, as well as in the heart. We safely performed biopsy of the lymph nodes and diagnosed the patient with primary cardiac lymphoma. We concluded that echocardiography and FDG‐PET are useful for selecting an appropriate biopsy site in primary cardiac lymphoma. 相似文献