全文获取类型
收费全文 | 17485篇 |
免费 | 864篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 241篇 |
妇产科学 | 109篇 |
基础医学 | 2057篇 |
口腔科学 | 371篇 |
临床医学 | 1105篇 |
内科学 | 4434篇 |
皮肤病学 | 297篇 |
神经病学 | 1400篇 |
特种医学 | 903篇 |
外科学 | 3042篇 |
综合类 | 62篇 |
预防医学 | 555篇 |
眼科学 | 419篇 |
药学 | 1189篇 |
中国医学 | 47篇 |
肿瘤学 | 2143篇 |
出版年
2023年 | 134篇 |
2022年 | 246篇 |
2021年 | 449篇 |
2020年 | 240篇 |
2019年 | 312篇 |
2018年 | 357篇 |
2017年 | 329篇 |
2016年 | 396篇 |
2015年 | 424篇 |
2014年 | 553篇 |
2013年 | 644篇 |
2012年 | 1003篇 |
2011年 | 1135篇 |
2010年 | 639篇 |
2009年 | 552篇 |
2008年 | 934篇 |
2007年 | 1075篇 |
2006年 | 1032篇 |
2005年 | 1088篇 |
2004年 | 994篇 |
2003年 | 932篇 |
2002年 | 966篇 |
2001年 | 323篇 |
2000年 | 298篇 |
1999年 | 323篇 |
1998年 | 265篇 |
1997年 | 186篇 |
1996年 | 201篇 |
1995年 | 170篇 |
1994年 | 167篇 |
1993年 | 149篇 |
1992年 | 227篇 |
1991年 | 188篇 |
1990年 | 150篇 |
1989年 | 145篇 |
1988年 | 124篇 |
1987年 | 119篇 |
1986年 | 126篇 |
1985年 | 104篇 |
1984年 | 73篇 |
1983年 | 68篇 |
1982年 | 48篇 |
1981年 | 40篇 |
1980年 | 37篇 |
1979年 | 37篇 |
1977年 | 48篇 |
1973年 | 38篇 |
1970年 | 34篇 |
1969年 | 52篇 |
1968年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The integrity of the sensory nervous system in the anal canals of chronically constipated children was investigated using
evoked potential techniques examining cerebral and spinal evoked potentials from the lower extremities and anal canal. Stimulation
of the posterior tibial nerve produced no significant difference in the parameters of spinal and cerebral evoked potentials
between 18 controls and 12 chronically constipated chidren. However, stimulation of the anal canal resulted in evoked potentials
related to the age and/or consciousness level of the control children. Reproducible cerebral responses were obtained only
from nine of these control children, all aged over 4 years, who were examined while awake without sedatives. A typical response
was characterized by a polyphasic wave occurring with an onset latency of 79.4± 27.7ms (mean ±SD). In the 12 chronically constipated
children, the 5 sedated patients examined while asleep did not show any reproducible potential, as in the controls. However,
in the remaining 7 children examined while awake, the occurrence of the anal canal evoked potential was significantly reduced,
and only two exhibited a cerebral response. These findings suggest that rectal mucosal perception of the intraluminal stimuli
might be disturbed in some children with chronic constipation. 相似文献
52.
Yasuna Kobayashi Ryoko Sakai Naomi Ohshiro Masayuki Ohbayashi Noriko Kohyama Toshinori Yamamoto 《Drug metabolism and disposition》2005,33(5):619-622
Organic anion transporter 2 (Oat2 [SLC22A7]) is a multispecific organic anion transporter. Although several substrates of human Oat2 (hOat2) have been elucidated, a possible involvement of hOat2 in drug interaction is less defined. The purpose of this study was to investigate the interaction of theophylline with erythromycin mediated by hOat2 using a Xenopus laevis oocyte expression system. When expressed in Xenopus oocytes, hOat2 mediated the transport of theophylline and erythromycin. The finding indicates that the two compounds are novel substrates for hOat2. The apparent K(m) values for the uptake of hOat2 that mediated the transport of theophylline and erythromycin were 12.6 muM and 18.5 muM, respectively. The hOat2-mediated uptake of [(14)C]theophylline and [(14)C]erythromycin was cis-inhibited by adding erythromycin and theophylline, respectively. Our present findings suggest that hOat2 may, at least in part, be involved in the theophylline-erythromycin interaction in the human liver. 相似文献
53.
Dendritic Cells Coinjected with Tumor Cells Treated with an Anticancer Drug to Induce Tumor Rejection 总被引:1,自引:0,他引:1
Naoya Inoue Seiji Yamasaki Kan Kondo Takatsugu Kan Katsuyoshi Furumoto Masayuki Imamura 《Surgery today》2003,33(4):269-276
Purpose: We examined whether bone marrow-derived dendritic cells (DCs) could induce antitumor immunity when a chemotherapeutic drug
was added.
Methods: CT26 (a murine colon cancer cell line syngeneic with BALB/c) and CT26-bearing mice were treated with mitomycin C (MMC) intraperitoneally
(i.p.). Next, mice immunized with a coinjection of DCs and MMC-treated CT26 (i.p.) were given an intradermal inoculation of
CT26. Finally, CT26-bearing mice were treated with MMC (i.p.) with or without DCs, given peritumorally.
Results: Although the inoculated tumor was not rejected in the control mice, CT26 was rejected in 50% of the mice injected with MMC
alone. Apoptosis was observed in the MMC-treated CT26 cells in vitro and in vivo. Immunization with DCs and apoptotic CT26
cells, but not with apoptotic CT26 alone, gave protection against tumor challenge in 7 of 13 mice. A significantly higher
level of cytotoxic T-cell activity and interferon-γ production was seen in the protected mice. When MMC (i.p.) treatment was
followed by peritumoral DC injection in the CT26-bearing mice, remarkable therapeutic effects were observed.
Conclusion: DCs can collaborate with chemotherapy-induced apoptotic tumor cells and elicit improved antitumor immunity, probably through
the acquisition of tumor-associated antigens from apoptotic tumor cells.
Received: January 7, 2002 / Accepted: September 3, 2002
Acknowledgments. We thank Dr. Kazuo Kinoshita for his useful advice on using flow cytometry. This research was partly supported by the Ministry
of Education, Culture, Sports, Science and Technology (No. 11671160).
Reprint requests to: S. Yamasaki 相似文献
54.
Songji Zhao Yuji Kuge Takafumi Mochizuki Toshiyuki Takahashi Kunihiro Nakada Masayuki Sato Toshiki Takei Nagara Tamaki 《Journal of nuclear medicine》2005,46(4):675-682
The biologic mechanisms involved in the intratumoral heterogeneous distribution of 18F-FDG have not been fully investigated. To clarify factors inducing heterogeneous 18F-FDG distribution, we determined the intratumoral distribution of 18F-FDG by autoradiography (ARG) and compared it with the regional expression levels of glucose transporters Glut-1 and Glut-3 and hexokinase-II (HK-II) in a rat model of malignant tumor. METHODS: Rats were inoculated with allogenic hepatoma cells (KDH-8) into the left calf muscle (n = 7). Tumor tissues were excised 1 h after the intravenous injection of 18F-FDG and sectioned to obtain 2 adjacent slices for ARG and histochemical studies. The regions of interest (ROIs) were placed on ARG images to cover mainly the central (CT) and peripheral (PT) regions of viable tumor tissues and necrotic/apoptotic (NA) regions. The radioactivity in each ROI was analyzed quantitatively using a computerized imaging analysis system. The expression levels of Glut-1, Glut-3, and HK-II were determined by immunostaining and semiquantitative evaluation. The hypoxia-inducible factor 1 (HIF-1) was also immunostained. RESULTS: ARG images showed that intratumoral 18F-FDG distribution was heterogeneous. The accumulation of 18F-FDG in the CT region was the highest, which was 1.6 and 2.3 times higher than those in the PT and NA regions, respectively (P < 0.001). The expression levels of Glut-1, Glut-3, and HK-II were markedly higher in the CT region (P < 0.001) compared with those in the PT region. The intratumoral distribution of 18F-FDG significantly correlated with the expression levels of Glut-1, Glut-3, and HK-II (r = 0.923, P < 0.001 for Glut-1; r = 0.829, P < 0.001 for Glut-3; and r = 0.764, P < 0.01 for HK-II). The positive staining of HIF-1 was observed in the CT region. CONCLUSION: These results demonstrate that intratumoral 18F-FDG distribution corresponds well to the expression levels of Glut-1, Glut-3, and HK-II. The elevated expression levels of Glut-1, Glut-3, and HK-II, induced by hypoxia (HIF-1), may be contributing factors to the higher 18F-FDG accumulation in the CT region. 相似文献
55.
56.
Prevalence rates and risk factors for allergic symptoms among inhabitants in rural districts 总被引:1,自引:0,他引:1
A Ueda T Ueda T Matsushita T Ueno S Nomura 《Sangyō igaku. Japanese journal of industrial health》1987,29(1):3-16
In order to determine the prevalence of allergic disorders and their association with agricultural factors, a total of 3,717 inhabitants of rural districts in Kumamoto Prefecture were ashed to fill out a questionnaire concerning their allergic status. The results obtained were as follows: One or more items of allergic symptoms were reported by 44% of the subjects. The prevalence rate of each symptom was 8% for respiratory organs, 5% for delayed type of respiratory disorders, 10% for nasal mucosa, 16% for eyes, 16% for urticaria-like derma and 26% for eczema-like derma. Twenty-one percent of the subjects had past histories of allergic diseases such as asthma (3%), nasal allergy (3%), urticaria (6%), contact dermatitis (9%) and so forth. These allergic conditions were seen to be more common among farmers than non-agricultural workers, and also among subjects with allergic constitution than those without such constitution. The highest (62%) prevalence of allergic symptoms was observed in farmers engaged in poultry raising, followed by those engaged in raising flowers (58%), tobacco (58%), cortinellus shiitake (55%), cucumber in plastic greenhouse (53%) and mandarin orange (53%). Among the symptomatic subjects, 12-38% of those with each symptom gave farm work as the direct causative factor for developing the corresponding symptom. Pesticide spraying was the most common agent among those factors. 相似文献
57.
Atsuhiko Chiba Tatsuo Akema Masayuki Iigo Yuta Nagami Fukuko Kimura Jun-ichi Toyoda 《Journal of neuroendocrinology》1998,10(2):79-84
It has been recently reported that acute immobilization stress almost completely suppresses the luteinizing hormone (LH) release induced by naloxone, a μ-opioid antagonist, in ovariectomized estrogen-primed rats. The present study examined the possible involvement of the pineal gland in the acute immobilization-related suppression of the naloxone-induced LH release. An intraventricular (ICV) injection of 15 μg naloxone produced an abrupt increase in circulating LH concentrations in non-stressed rats. The naloxone-induced LH release was completely eliminated when tested 60 min after the end of a 30 min session of acute immobilization. The same stress conditions did not affect LH-releasing hormone (LHRH)-induced LH release, suggesting that the stress-related suppression of the naloxone-induced LH release was a suprapituitary event. In chronically-pinealectomized rats, but not in sham-pinealectomized rats, naloxone injected 60 min after the end of the stress session evoked a significant increase in serum LH concentrations. However, naloxone injected ICV during the acute immobilization did not elicit LH release in either pinealectomized or sham-operated rats. Under non-stressed conditions, the LH secretory response to naloxone was similar in pinealectomized and sham-operated animals. The same stress (30 min immobilization) significantly increased pineal melatonin content as well as plasma melatonin concentrations in rats bearing intact pineal glands, indicating that stress actually affected the pineal function. These results provide evidence for a role of the pineal in the suppression of the LH response to naloxone after stress, but not during stress. 相似文献
58.
Kaoru Nagahori Jun Itakura Hiroyasu Miura Hidemitsu Sugai Masayuki Yamamoto Yoshiro Matsumoto Takao Ainota Yoshihiro Akahane 《Journal of Hepato-Biliary-Pancreatic Surgery》1995,2(3):288-291
We report a metastatic pulmonary tumor resected by video-assisted thoracoscopic surgery. A 63-year-old female was found to
have four nodules of hepatocellular carcinoma (HCC) in January 1991; after non-surgical treatment, the tumors had become necrotic.
In June 1992, a new HCC nodule was found. After infusion chemotherapy, it became necrotic. In September 1993, a solitary lung
tumor, 2.4 cm in diameter, appeared at the periphery of the right lung. Because the tumor was considered to be a metastatic
HCC rather than a primary lung cancer, it was removed by thoracoscopic wedge resection. Although whether metastasectomy contributes
to prolongation of survival is still controversial, thoracoscopic pulmonary resection may be indicated for solitary peripheral
metastasis, if the primary HCC is well controlled by multidisciplinary treatment. 相似文献
59.
Tomimori Y Muto T Fukami H Saito K Horikawa C Tsuruoka N Saito M Sugiura N Yamashiro K Sumida M Kakutani S Fukuda Y 《Laboratory investigation; a journal of technical methods and pathology》2002,82(6):789-794
An epicutaneous application of 2,4-dinitrofluorobenzene (DNFB) to a mouse ear caused a transient skin swelling, and the repetition of the challenge enlarged the contact dermatitis. The repeated challenge with DNFB also induced eosinophil infiltration on the application site. Administration of a chymase inhibitor significantly inhibited the ear swelling as well as eosinophil accumulation. An intradermal injection of human chymase to the mouse ear also elicited transient skin swelling and eosinophil infiltration, both of which were augmented in proportion to the number of injections. Human serum albumin and heat-inactivated chymase failed to induce such skin reactions, suggesting the participation of proteolytic activity of the enzyme. In addition, chymase stimulated eosinophil migration in vitro in a concentration-dependent manner. Taken together, these observations suggest that mast cell chymase may contribute to development of the DNFB-induced dermatitis, probably by promoting eosinophil infiltration. It is therefore possible that chymase plays a role in pathogenesis of chronic dermatitis such as atopic dermatitis. 相似文献
60.
The activities of glycogen synthetase and phosphorylase were electron histochemically examined in the retina of the fetal chick. These enzyme activities appeared in the cytoplasmic matrices of the developing paraboloid in the photoreceptor inner segment almost simultaneously at the 17th day of incubation. After the appearance of these 2 enzyme activities, glycogen particles were found in the developing paraboloid. It is concluded that glycogen is synthesized through the enzymatic pathway in the fetal retina and that glycogen is not found before the enzymes related to glycogen metabolism appear in the cell except the appearance of native glycogen in the egg. Branching glycosyltransferase seemed to appear after phosphorylase was activated and these enzymes became higher in their activity with the differentiation in the paraboloid in the fetal and early postnatal periods. 相似文献