全文获取类型
收费全文 | 12501篇 |
免费 | 581篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 147篇 |
儿科学 | 186篇 |
妇产科学 | 193篇 |
基础医学 | 1620篇 |
口腔科学 | 251篇 |
临床医学 | 790篇 |
内科学 | 3625篇 |
皮肤病学 | 335篇 |
神经病学 | 896篇 |
特种医学 | 445篇 |
外科学 | 1682篇 |
综合类 | 64篇 |
预防医学 | 290篇 |
眼科学 | 172篇 |
药学 | 1076篇 |
中国医学 | 39篇 |
肿瘤学 | 1322篇 |
出版年
2023年 | 57篇 |
2022年 | 113篇 |
2021年 | 222篇 |
2020年 | 132篇 |
2019年 | 152篇 |
2018年 | 209篇 |
2017年 | 162篇 |
2016年 | 203篇 |
2015年 | 248篇 |
2014年 | 273篇 |
2013年 | 345篇 |
2012年 | 644篇 |
2011年 | 730篇 |
2010年 | 393篇 |
2009年 | 318篇 |
2008年 | 631篇 |
2007年 | 706篇 |
2006年 | 629篇 |
2005年 | 639篇 |
2004年 | 685篇 |
2003年 | 717篇 |
2002年 | 684篇 |
2001年 | 400篇 |
2000年 | 411篇 |
1999年 | 347篇 |
1998年 | 157篇 |
1997年 | 99篇 |
1996年 | 117篇 |
1995年 | 96篇 |
1994年 | 114篇 |
1993年 | 89篇 |
1992年 | 222篇 |
1991年 | 187篇 |
1990年 | 172篇 |
1989年 | 198篇 |
1988年 | 157篇 |
1987年 | 171篇 |
1986年 | 146篇 |
1985年 | 159篇 |
1984年 | 107篇 |
1983年 | 104篇 |
1982年 | 54篇 |
1981年 | 55篇 |
1980年 | 51篇 |
1979年 | 77篇 |
1978年 | 53篇 |
1977年 | 49篇 |
1975年 | 46篇 |
1970年 | 46篇 |
1967年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Yoshinori Ebato Yoshinori Kato Hiraku Onishi Tsuneji Nagai Yoshiharu Machida 《Drug development research》2003,58(3):253-257
A simple method for the preparation of the inner liposomes for double liposomes (DL) was developed. The encapsulation efficiency of erythrosine in liposomes prepared by this new method is superior to that of the previous method because of the concentration of the drug in the lipid membrane. To evaluate the usefulness of DL prepared by the glass‐filter method modified in this study as an oral dosage form of salmon calcitonin (SCT), a suspension of liposomes containing SCT was administered to rats at a dose of 10 μg SCT/kg. Each type of DL showed better efficacy than its inner liposomes alone. The decrease in plasma calcium level was dependent on the electrical charge and particle size of the inner liposomes. The hypocalcemic efficacy of DL encapsulating SCT‐loading cationic liposomes relative to that after subcutaneous administration of SCT at a dose of 1 μg/kg was 6.47%, which was the largest value obtained. These results indicated that not only the particle size but also the electrical charge of inner liposomes affect intestinal absorption. This study verified that the efficacy was increased because of the decrease in diameter of the inner liposomes and the use of lipid with a positive charge. These findings concluded that DL might be useful as an oral dosage form of SCT. Drug Dev. Res. 58:253–257, 2003. © 2003 Wiley‐Liss, Inc. 相似文献
102.
Ogata T Kurabayashi M Hoshino YI Sekiguchi KI Kawai-Kowase K Ishikawa S Morishita Y Nagai R 《Transplantation》2000,70(11):1653-1656
103.
104.
Toshio Yoshihara Keiko Nagai 《International journal of pediatric otorhinolaryngology》1997,40(2-3):181-187
A rare case of a 5-year-old female with schwannoma of the maxillary sinus is presented. She had complained of painless swelling of the left cheek and hard palate for a duration of one year. Preoperatively, a CT scan strongly suggested it to be a maxillary cyst with an erupted tooth rather than neoplasm. The tumour was completely removed after embolization of the left internal maxillary artery. The tumour was composed of spindle cells in a palisading pattern and intercellular collagenous fibres. Mitotic figures and atypical nuclei were not observed. Immunohistochemically, the majority of the cells were positive for NSE and S-100 protein, whereas GFA and PCNA showed little immunoreaction. The pathological diagnosis was Antony type A of schwannoma arising in the maxillary sinus. 相似文献
105.
The epipharynx lies between the nasal cavity and oropharynx. The mucosa of the epithelium in the human epipharynx is composed of ciliated epithelium as part of the respiratory tract, squamous epithelium as representative of the digestive system and transitional epithelium. Previous studies by Ali have shown that transitional epithelium is present in a boundary line between the epipharynx and oropharynx, with numerous islets of the epithelium also located in the lateral and dorsal walls accompanied with a patchy distribution of the ciliated and squamous epithelium. Mechanical irritation caused by the anatomical properties of the epipharynx is thought to be responsible for the morphological findings present. We studied the distribution of the three different types of epithelia in the epipharynx in ten autopsy cases. Our data revealed that they showed mosaic or an “island-like” distribution on the epipharyngeal wall and their patterns of distribution were variable in each individual. 相似文献
106.
Tomoko Ohtsu Hirofumi Fujii Hisashi Wakita Tadahiko Igarashi Kuniaki Itoh Shigeru Imoto Masahiro Kohagura Yasutsuna Sasaki 《Cancer chemotherapy and pharmacology》1998,42(1):1-8
The present study was conducted to compare the pharmacokinetics (PK) of low-dose versus high-dose medroxyprogesterone (MPA)
as a once-daily oral administration. Of 32 patients, all women, enrolled in this PK study, 18 received 600 mg MPA daily and
14 received 1200 mg daily. Detailed PK data were obtained on day 1 and after more than 4 weeks of MPA treatment. In addition,
multiple data for the minimum steady-state concentration (Css min) were analyzed. The MPA serum concentrations were measured
by high-performance liquid chromatography. Wide interpatient variability was found in the PK parameters obtained both on day
1 and after more than 4 weeks. There were no clear relationships between the oral dose and the MPA peak concentration (Cmax),
area under the time versus concentration curve (AUC), or mean Css min. Weight gains of 10% or more were demonstrated more
frequently in the high-dose group (P<0.01). Liver dysfunction (n=5) did not influence the PK of MPA. Five patients demonstrated extremely low AUC and Cmax (<10 ng/ml) values on day 1. Phenobarbital,
dexamethasone and betamethasone were being taken concomitantly with the MPA each by one patient. The serum MPA concentrations
were markedly increased after the discontinuation of phenobarbital in that patient, suggesting a drug interaction. At present
we cannot recommend the high dose of MPA, except in clinical studies, from a PK or a pharmacodynamic points of view.
Received: 2 May 1997 / Accepted: 13 October 1997 相似文献
107.
The role of computed tomographic scanning in diagnosing mediastinal node involvement in non-small cell lung cancer 总被引:10,自引:0,他引:10
Takamochi K Nagai K Yoshida J Suzuki K Ohde Y Nishimura M Takahashi K Nishiwaki Y 《The Journal of thoracic and cardiovascular surgery》2000,119(6):1135-1140
OBJECTIVES: The reliability of computed tomographic scanning in evaluating mediastinal node involvement is controversial because of the high false result rate. We attempted to identify significant factors responsible for false-positive and false-negative scans. METHODS: From August 1992 through April 1997, 401 patients with lung cancer who underwent major lung resection and systematic lymph node dissection were enrolled in this study. We retrospectively examined mediastinal node size, tumor location, maximum tumor dimension, the presence or absence of obstructive pneumonia, atelectasis, pulmonary fibrosis, and lymph node calcification on contrast-enhanced computed tomographic scans. We identified clinical and radiologic factors responsible for the false results by using univariate and multivariable analysis. RESULTS: Central tumor location proved to be a significant factor of false-positive scans. Elevated carcinoembryonic antigen level and larger tumor dimension were significant factors of false-negative scans. In patients with a peripheral tumor smaller than 40 mm and normal levels of serum carcinoembryonic antigen, sensitivity, specificity, positive predictive value, and negative predictive value were 6%, 93%, 8%, and 90%, respectively. The reliability of computed tomographic scanning in this low-risk subgroup was high in detecting N0-1 disease but low in diagnosing N2 disease. CONCLUSION: It is not possible to accurately diagnose N2 disease by using lymph node size on computed tomographic scanning alone, especially in patients with a central tumor, an elevated serum carcinoembryonic antigen level, or a tumor of 40 mm or larger. A preoperative invasive staging procedure is indicated in these populations and may not be indicated in the population with normal computed tomographic scan results without any of these risk factors. 相似文献
108.
Shin Kariya Mitsuhiro Okano Hisashi Hattori Yuji Sugata Rie Matsumoto Kunihiro Fukushima Patricia A Schachern Sebahattin Cureoglu Michael M Paparella Kazunori Nishizaki 《Otology & neurotology》2006,27(8):1089-1093
OBJECTIVE: Otitis media with effusion is one of the most common and intractable ear diseases. However, the role of Th1, Th2, and immunoregulatory cytokines on the pathogenesis of the disease in adult patients remains to be determined. The aim of this study is to disclose the cytokine expression in middle ear effusions (MEEs) in adults and to compare the profile on the basis of the presence of allergic rhinitis and the type of effusions. STUDY DESIGN: A prospective controlled clinical study. PATIENTS: MEEs were collected from 80 adult subjects. The concentration of interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, and interferon (IFN)-gamma in MEEs were determined by using enzyme-linked immunosorbent assay. RESULTS: IL-2, IL-4, IL-5, IL-10, IL-12, and IFN-gamma in MEEs were detected in 60 (75.0%), 33 (41.3%), 42 (52.5%), 14 (17.5%), 80 (100%), and 66 (82.5%) samples, respectively. Among these cytokines, only the concentration of IL-4 in the allergic rhinitis-positive group was significantly higher than that in the allergic rhinitis-negative group. On the other hand, IL-2, IL-12, and IFN-gamma were detected, regardless of the presence of allergic rhinitis, and the concentration of these cytokines correlated with each other. The correlation between the concentration of IL-4 and IL-5 was also detected. In addition, both the incidence rate and the concentration of IL-10 in MEEs were significantly higher in the mucoid type compared with those in the serous type effusions. CONCLUSION: Regardless of allergic status, IL-12 may play a critical role in the pathogenesis of otitis media with effusion by affecting the production of IL-2 and IFN-gamma. In addition, IL-4 may have some impact on the immunologic condition in adults with allergic rhinitis. IL-10 potentially affects the viscosity of MEEs. 相似文献
109.
No Improvement of Adult Height in Non-growth Hormone (GH) Deficient Short
Children with GH Treatment
Toshiaki Tanaka Kenji Fujieda Susumu Yokoya Akira Shimatsu Katsuhiko Tachibana Hiroyuki Tanaka Takakuni Tanizawa Akira Teramoto Toshiro Nagai Yoshikazu Nishi Yukihiro Hasegawa Kunihiko Hanew Keinosuke Fujita Reiko Horikawa Goro Takada Masao Miyashita Tadashi Ohno Kazuo Komatsu 《Clinical Pediatric Endocrinology》2006,15(1):15-21
It is still in doubt whether the standard-dose growth hormone (GH) used in Japan (0.5
IU/kg/week, 0.167 mg/kg/week) for growth hormone deficiency is effective for achieving
significant adult height improvement in non-growth hormone deficient (non-GHD) short
children. We compared the growth of GH-treated non-GHD short children with that of
untreated short children to examine the effect of standard-dose GH treatment on non-GHD
short children. GH treatment with recombinant human growth hormone (rhGH) was started
before the age of 11 yr in 64 boys and 76 girls with non-GHD short stature registered at
the Foundation for Growth Science who have now reached their adult height. In 119
untreated boys and 127 untreated girls whose height standard deviation score (SDS) was
below –2 SD at the age of 6 yr, height growth was followed until 17 yr. Height SDS was
significantly lower before GH treatment in the GH-treated group than at the age of 6 yr in
the untreated group, in both sexes. Adult height and adult height SDS were significantly
greater in the untreated group than in the GH-treated group, in both sexes, although the
change in height SDS did not differ significantly. Height SDS was significantly lower
before GH treatment in the GH-treated group than at the age of 6 yr in the untreated
group, so 57 boys and 57 girls whose height SDS at the age of 6 yr in the untreated group
closely matched the height SDS before GH treatment in the GH-treated group were chosen for
comparison. Height SDS did not differ significantly between the GH-treated group before GH
treatment and the untreated group at the age of 6 yr, nor were there differences between
these subgroups in adult height, adult height SDS, or height SDS change, in either sex.
The effect of GH treatment is reported to be dose-dependent and doses over 0.23 mg/kg/week
are reported to be necessary to improve adult height in non-GHD short children. Currently,
the GH dose is fixed at 0.175 mg/kg/week in Japan, and we expected to find, and indeed
concluded, that ordinary GH treatment in Japanese, non-GHD short children does not improve
adult height. 相似文献
110.
Prognostic significance of the size of central fibrosis in peripheral adenocarcinoma of the lung 总被引:18,自引:0,他引:18
Suzuki K Yokose T Yoshida J Nishimura M Takahashi K Nagai K Nishiwaki Y 《The Annals of thoracic surgery》2000,69(3):893-897
BACKGROUND: The prognostic significance of the characteristics of central fibrosis in peripheral adenocarcinoma of the lung has been reported. However, the prognostic significance of the size of central fibrosis has never been evaluated. METHODS: A total of 100 consecutive surgically resected peripheral adenocarcinomas of the lung measuring 3.0 cm or less in maximum dimension were reviewed histologically, and the maximum dimension of central fibrosis was measured on conventional hematoxylin and eosin stain. RESULTS: Median follow-up for patients alive was 54 months. The overall 5-year survival rate was 75%. Twenty-one patients with adenocarcinoma having central fibrosis 5 mm or smaller in maximum dimension had a 5-year survival rate of 100%, whereas the other 79 patients had a 5-year survival less than 70%. Multivariate analysis showed the size of central fibrosis to be an independent prognostic factor as significant as vascular invasion and locoregional lymph node metastasis (p = 0.010, 0.024, and 0.024, respectively). CONCLUSIONS: The size of central fibrosis is an independent prognostic factor in peripheral lung adenocarcinoma, as significant as the well-established prognostic factors vascular invasion and lymph node metastasis. 相似文献