全文获取类型
收费全文 | 12759篇 |
免费 | 575篇 |
国内免费 | 78篇 |
专业分类
耳鼻咽喉 | 273篇 |
儿科学 | 178篇 |
妇产科学 | 75篇 |
基础医学 | 1681篇 |
口腔科学 | 279篇 |
临床医学 | 807篇 |
内科学 | 3037篇 |
皮肤病学 | 152篇 |
神经病学 | 771篇 |
特种医学 | 508篇 |
外科学 | 2589篇 |
综合类 | 42篇 |
一般理论 | 2篇 |
预防医学 | 405篇 |
眼科学 | 146篇 |
药学 | 739篇 |
中国医学 | 22篇 |
肿瘤学 | 1706篇 |
出版年
2023年 | 70篇 |
2022年 | 145篇 |
2021年 | 255篇 |
2020年 | 137篇 |
2019年 | 189篇 |
2018年 | 270篇 |
2017年 | 214篇 |
2016年 | 277篇 |
2015年 | 281篇 |
2014年 | 363篇 |
2013年 | 422篇 |
2012年 | 701篇 |
2011年 | 754篇 |
2010年 | 458篇 |
2009年 | 405篇 |
2008年 | 647篇 |
2007年 | 694篇 |
2006年 | 727篇 |
2005年 | 695篇 |
2004年 | 669篇 |
2003年 | 643篇 |
2002年 | 618篇 |
2001年 | 302篇 |
2000年 | 274篇 |
1999年 | 271篇 |
1998年 | 170篇 |
1997年 | 127篇 |
1996年 | 113篇 |
1995年 | 108篇 |
1994年 | 93篇 |
1993年 | 94篇 |
1992年 | 205篇 |
1991年 | 202篇 |
1990年 | 188篇 |
1989年 | 174篇 |
1988年 | 174篇 |
1987年 | 181篇 |
1986年 | 147篇 |
1985年 | 137篇 |
1984年 | 90篇 |
1983年 | 69篇 |
1982年 | 45篇 |
1980年 | 36篇 |
1979年 | 67篇 |
1978年 | 41篇 |
1977年 | 36篇 |
1973年 | 38篇 |
1971年 | 42篇 |
1968年 | 41篇 |
1967年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Hideyuki Masuda Makoto Kimura Akiko Nishioka Hiroshi Kato Akimichi Morita 《Journal of dermatological science》2019,93(2):109-115
Background
Photosensitizers used for photodynamic therapy (PDT) to treat dermatologic disease are metabolized into mainly protoporphyrin IX (PpIX), which has five absorption wavelength peaks: 410?nm, 510?nm, 545?nm, 580?nm, and 630?nm. Although only red light around 635?nm and blue light around 400?nm are used as light sources for PDT, the efficiency of PDT might be improved by using multiple wavelengths, including those that correspond to the other absorption peaks of PpIX. Furthermore, because the target disease often occurs on the face, a flexible-type light-source unit that can be fitted to the lesion without unnecessarily exposing the mucous membranes, e.g., the eyes, nostrils, and mouth, is preferred.Objective
We investigated the efficacy of a flexible light-emitting diode (LED) unit that emits multiple wavelengths to improve PDT effects.Methods
HaCaT cells were incubated with 5-ALA and subsequently irradiated with either a single wavelength or sequentially with two wavelengths. Cell viability and reactive oxygen species were analyzed. Nude mice were implanted with COLO679 cells by subcutaneous injection into the flank. 5-ALA was subcutaneously injected into the tumor. The tumor was irradiated with 50?J/cm2 (day 0) and assessed daily until day 21.Results
The synergistic PDT effects of dual-wavelength irradiation and reactive oxygen species production were highest with the 405-nm and 505-nm wavelength combination. This dual wavelength combination was also the most effective in vivo.Conclusion
We could therefore conclude that dual-wavelength PDT is an efficient strategy for improving the therapeutic effects of PDT. Using a flexible LED unit is expected to achieve more uniform irradiation of uneven areas. 相似文献2.
3.
Tetsuro Sano Munetaka Masuda Shigeki Morita Hisataka Yasui 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2006,54(4):149-154
OBJECTIVE: It is well documented that cardiopulmonary bypass (CPB) severely impairs cellular immunity. The objective of this study was to investigate the effect of prostaglandin E1 (PGE1) on cellular immunity after CPB. METHODS: Patients who underwent elective cardiac surgery were randomly divided into the PGE1 group (n=12) and the control group (n=12). In the PGE1 group, PGE1 was administered at 20 ng/kg/min from just after the induction of anesthesia to the end of surgery. Peripheral blood mononuclear cells (PBMCs) were taken before anesthesia and on postoperative days 1, 3 and 7 (POD 1, POD 3 and POD 7). Proliferation responses of T cells to phytohemagglutinin (PHA) and pure protein derivative (PPD) antigen were measured as indicators of cellular immunity. RESULTS: PGE1 significantly attenuated the impairment of both PHA and PPD response after cardiac surgery on POD 1 (PHA response, 30 +/- 21% vs. 53 +/- 32%, control vs. PGE, p=0.048; PPD response, 18 +/- 21% vs. 39 +/- 27%, control vs. PGE, p=0.046). The reduced glutathione content of PBMCs in the control group was significantly decreased on POD 1. CONCLUSION: PGE1 attenuated the impairment of cellular immunity after cardiac surgery with CPB by reducing oxidative stress on PBMCs. 相似文献
4.
Koichi Masuda Robert L Sah Michael J Hejna Eugene J-M A Thonar 《Journal of orthopaedic research》2003,21(1):139-148
Most attempts to tissue-engineer cartilage have involved seeding of cultured cells into a biological or synthetic scaffold. We have developed a novel two-step culture approach that makes possible the in vitro formation of cartilaginous-like tissue by mature adult bovine chondrocytes without the aid of a synthetic matrix. The first step consists of culturing chondrocytes under conditions that maintain their rounded shape and their molecular phenotype as assessed by type II collagen and aggrecan production. This step was accomplished by culturing the isolated chondrocytes in alginate beads until the cells have reestablished a proteoglycan-rich cell-associated matrix (CM). The second step consists of culturing the cells with their CM, after recovery from the beads, on a tissue culture insert with a porous membrane. In this study, young adult bovine articular chondrocytes were cultured in alginate beads in the presence of 10% or 20% fetal bovine serum (FBS). After 7 days of culture, the alginate beads were dissolved by incubating the beads for 20 min in sodium citrate buffer, a calcium chelator. Following a brief centrifugation, the cells with their CM were recovered, resuspended in medium containing 10% or 20% FBS and seeded onto a tissue culture insert. After 1 week of culture on the insert, the individual cells with their CM progressively became incorporated into a mass of cartilaginous tissue. Culture with 20% FBS resulted in the best formation of tissues. These tissues, easily recovered from the insert, were then subjected to biochemical and histological analyses. The biochemical results showed that the chondrocytes remain phenotypically stable in the tissues. The de novo tissue has a relatively high ratio of PG/collagen. Histological examination of the tissue revealed it contained a cartilage-like matrix strongly stained with toluidine blue. This scaffold-free system appears ideal to study, in vitro, the development of transplantable cartilaginous tissue. 相似文献
5.
Yuji Masuda Toyonobu Yamashita Tetsuji Hirao Motoji Takahashi 《Skin research and technology》2009,15(2):224-229
Background/purpose: It is crucial to establish an accurate method for measuring skin pigmentation in cosmetic science and clinical dermatology. Here, we report a non-invasive precise method for measuring skin melanin content.
Methods: In order to determine the concentrations of melanin and hemoglobin in skin, we used the spectrum resolution (SR) method. In brief, the absorption spectrum of the skin was calculated from the reflection spectrum using a spectrophotometer. The concentrations of melanin and hemoglobin were then determined using a multiple regression analysis, assuming that the absorption spectrum of the skin is expressed as a linear summation of the absorptions of melanin and hemoglobin according to the Lambert–Beer law. The skin changes in the volar forearm, which had been irradiated by ultraviolet rays (UV), were observed daily by the SR method.
Results: A multiple regression analysis with an absorption spectrum of 500–700 nm was performed. The multiple correlation coefficient was 0.993, resulting in a satisfactory precise estimate of the concentrations of melanin. After UV irradiation, the concentration of melanin monitored by the SR method increased until 8 days and decreased gradually afterwards.
Conclusions: The SR method allows the evaluation of the changes of epidermal melanin induced by UV irradiation. 相似文献
Methods: In order to determine the concentrations of melanin and hemoglobin in skin, we used the spectrum resolution (SR) method. In brief, the absorption spectrum of the skin was calculated from the reflection spectrum using a spectrophotometer. The concentrations of melanin and hemoglobin were then determined using a multiple regression analysis, assuming that the absorption spectrum of the skin is expressed as a linear summation of the absorptions of melanin and hemoglobin according to the Lambert–Beer law. The skin changes in the volar forearm, which had been irradiated by ultraviolet rays (UV), were observed daily by the SR method.
Results: A multiple regression analysis with an absorption spectrum of 500–700 nm was performed. The multiple correlation coefficient was 0.993, resulting in a satisfactory precise estimate of the concentrations of melanin. After UV irradiation, the concentration of melanin monitored by the SR method increased until 8 days and decreased gradually afterwards.
Conclusions: The SR method allows the evaluation of the changes of epidermal melanin induced by UV irradiation. 相似文献
6.
Mizuaki Sakura Satoru Kawakami Hitoshi Masuda Tsuyoshi Kobayashi Yukio Kageyama Kazunori Kihara 《International journal of urology》2007,14(12):1109-1112
Since 1998, we have performed minimum incision endoscopic surgery (MIES) for renal cell carcinoma (RCC). For seven dialysis patients with bilateral RCC, we have performed sequential bilateral MIES radical nephrectomy. It was carried out by retroperitoneal approach through a single minimum incision that narrowly permitted extraction of the specimen using endoscopy and direct stereovision, without trocar ports, without gas insufflation and without the insertion of the hands of operators into the operative field. Although six of the seven patients had multiple complications in addition to chronic renal failure (CRF), bilateral kidneys were successfully removed by sequential MIES radical nephrectomy without major operative complication. Postoperative recovery was prompt with all patients resuming oral feeding and walking by the second postoperative day. Sequential bilateral MIES radical nephrectomy, leaving the peritoneal cavity intact and without imposing circulatory stress caused by gas insufflation, is a feasible treatment for bilateral RCCs in dialysis patients. 相似文献
7.
Tadamasa Miyauchi Hiroshi Takiya Toshihiko Sawamura Eiji Murakami 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(4):206-209
Pericardial abscess is rare in healthy individuals, especially the amebic type. We report a case of pericardial abscess and
cardiac tamponade due to intrapericardial rupture of an amebic liver abscess. A 31-year old Japanese male complained of fever
to a local hospital. A liver mass was discovered in his left hepatic lobe by an abdominal echogram. He was referred to the
internal department of our hospital and was treated with quinolone antibiotics. Two weeks after medication, he suddenly complained
of epigastralgia and severe orthopnea and was admitted. Abdominal computed tomographic scan showed an enlarged liver mass,
and massive pericardial effusion suggested cardiac tamponade. He underwent an emergency subxiphoid partial pericardiectomy
under local anesthesia. 1,000 ml of light brownish fluid was removed and his condition improved. Although no ameba was cultivated
from the pus, the amebic serological test was positive. Metronidazole was administered and the patients was discharged 31
days after surgery. 相似文献
8.
We report a rare case of advanced renal cell carcinoma in apatient who showed complete resolution of metastases to thelung and bones after nephrectomy, partial jejunectomy and subsequentalpha-interferon therapy. The patient was a 54-year-old manwhose right lung and left femur metastases were detected beforenephrectomy. In the seventh week after nephrectomy, a partialjejunectomy was carried out because of the obstructive ileuscaused by intraluminal multiple metastases of the jejunum. Apathological fracture of the metastasized right humerus occurredsubsequently. After four months of intramuscular alpha-interferonadministration (3x106 units/day), however, x-rays revealed thecomplete disappearance of the metastatic lung shadow and a solidunion of the humerus, and there were no tumor cells in the femurspecimen resected at the subsequent reconstruction surgery ofthe left leg. Seven years have passed from onset, and the patientis still alive and disease free. 相似文献
9.
Y Masuda Y Harada E Honma T Ichimiya A Namiki 《Masui. The Japanese journal of anesthesiology》1990,39(3):383-387
We experienced anesthetic management of three cases of osteogenesis imperfecta. Case 1: A 2-year-old boy weighing 8.6 kg was premedicated with chloral hydrate 250 mg intrarectally, but he was very excited on arrival at the operating room. Induction of anesthesia was performed by intramuscular injection of ketamine 40 mg. Case 2: A 4-year-old girl underwent three surgeries (2 osteomies and 1 intramedullary nailing of the tibias) during the past two years. On the second and third procedures, marked hyperthermia (over 39.2 degrees C as rectal temperature) developed during halothane (1-2%) and enflurane (1.5-2.5%) anesthesia. However, on the first surgery, hyperthermia did not occur under combined light halothane (0.3-0.5%) anesthesia with caudal epidural block. Case 3: A 14-year-old female underwent osteotomy of the radius under brachial plexus block without any anesthetic complications. In conclusion, anesthetic considerations for children with this disease are as follows; 1) It is necessary to premedicate to provide good preoperative sedation. 2) Care should be taken to use inhaled anesthetic agents (halothane and enflurane) because of tendency to develop abnormal hyperthermia. 3) It is desirable to use regional anesthesia. 相似文献
10.