全文获取类型
收费全文 | 10366篇 |
免费 | 622篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 91篇 |
儿科学 | 249篇 |
妇产科学 | 301篇 |
基础医学 | 1514篇 |
口腔科学 | 235篇 |
临床医学 | 749篇 |
内科学 | 2457篇 |
皮肤病学 | 435篇 |
神经病学 | 764篇 |
特种医学 | 302篇 |
外科学 | 1309篇 |
综合类 | 39篇 |
预防医学 | 378篇 |
眼科学 | 262篇 |
药学 | 798篇 |
中国医学 | 29篇 |
肿瘤学 | 1136篇 |
出版年
2023年 | 57篇 |
2022年 | 149篇 |
2021年 | 225篇 |
2020年 | 151篇 |
2019年 | 246篇 |
2018年 | 265篇 |
2017年 | 229篇 |
2016年 | 275篇 |
2015年 | 264篇 |
2014年 | 352篇 |
2013年 | 416篇 |
2012年 | 630篇 |
2011年 | 684篇 |
2010年 | 378篇 |
2009年 | 331篇 |
2008年 | 551篇 |
2007年 | 634篇 |
2006年 | 633篇 |
2005年 | 628篇 |
2004年 | 595篇 |
2003年 | 530篇 |
2002年 | 565篇 |
2001年 | 215篇 |
2000年 | 208篇 |
1999年 | 194篇 |
1998年 | 140篇 |
1997年 | 88篇 |
1996年 | 96篇 |
1995年 | 59篇 |
1994年 | 70篇 |
1993年 | 58篇 |
1992年 | 113篇 |
1991年 | 108篇 |
1990年 | 107篇 |
1989年 | 133篇 |
1988年 | 95篇 |
1987年 | 84篇 |
1986年 | 62篇 |
1985年 | 63篇 |
1984年 | 42篇 |
1983年 | 32篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1979年 | 28篇 |
1978年 | 29篇 |
1977年 | 21篇 |
1975年 | 15篇 |
1973年 | 15篇 |
1970年 | 20篇 |
1968年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Shigeyuki Kitamura Tomoharu Suzuki Tomoko Kadota Mayumi Yoshida Koji Ohashi Shigeru Ohta 《Drug metabolism and disposition》2003,31(2):179-186
The in vitro metabolism of fenthion and its sulfoxide (fenthion sulfoxide) in sea bream (Pagrus major) and goldfish (Carassius auratus) was investigated and compared with that in rats. Fenthion was oxidized to fenthion sulfoxide and the oxon derivative, but not to its sulfone, in the presence of NADPH by liver microsomes of sea bream, goldfish, and rats. These liver microsomal activities of the fish were lower than those of rats but were of the same order of magnitude. The NADPH-linked oxon- and sulfoxide-forming activities of liver microsomes of the fish and rats were inhibited by SKF 525-A, metyrapone, alpha-naphthoflavone, and carbon monoxide. The oxidizing activity to fenthion sulfoxide was also inhibited by alpha-naphthylthiourea. Several cytochrome P450 isoforms and flavin-containing monooxygenase 1 exhibited these oxidase activities. Fenthion sulfoxide was reduced to fenthion with liver cytosol of the fish and rats upon addition of 2-hydroxypyrimidine, N(1)-methylnicotinamide, or butyraldehyde, each of which is an electron donor of aldehyde oxidase, under anaerobic conditions. The activity was inhibited by menadione, beta-estradiol, and chlorpromazine, which are inhibitors of aldehyde oxidase. The activities in the fish livers were similar to those of rat liver. Aldehyde oxidase purified from the livers of sea bream and rats exhibited the reducing activity. Thus, fenthion and fenthion sulfoxide are interconvertible in fish and rats through the activities of cytochrome P450, flavin-containing monooxygenase, and aldehyde oxidase. 相似文献
62.
Taro Semba Yasuhiro Funahashi Naoto Ono Yuji Yamamoto Naoko Hata Sugi Makoto Asada Kentaro Yoshimatsu Toshiaki Wakabayashi 《Clinical cancer research》2004,10(4):1430-1438
We reported previously that an angiogenesis inhibitor, E7820, inhibits in vitro tube formation of human umbilical vein endothelial cell through the suppression of integrin alpha2 expression. Here we describe the antiangiogenic and antitumor effects of E7820 in mice and discuss the feasibility of using platelet integrin alpha2 expression on platelets as a biological marker of the efficacy of E7820. Oral administration of E7820 significantly inhibited basic fibroblast growth factor-induced angiogenesis in Matrigel implants and human colon WiDr tumor-induced angiogenesis in a dorsal air sac model. Twice-daily treatment with E7820 clearly inhibited the s.c. tumor growth of seven tumor cell lines derived from human colon, breast, pancreas, and kidney, and completely suppressed the growth of human pancreatic KP-1 and human colon LoVo cell lines. Moreover, E7820 significantly inhibited the growth of KP-1 and human colon tumor Colo320DM cells orthotopically implanted in the pancreas and cecum, respectively. The efficacy of E7820 was comparable in the s.c. and orthotopic transplantation models. Immunohistochemical analyses using anti-CD31 antibody showed that E7820 significantly reduced microvessel density in orthotopically implanted KP-1 tumor. E7820 reduced integrin alpha2 expression on a megakaryocytic cell line, Dami cells, induced by phorbol 12-myristate 13-acetate treatment. It also decreased the expression level of integrin alpha2 on platelets withdrawn from mice bearing s.c. KP-1 tumor at a dosage close to that affording antitumor activity. These data demonstrate that E7820 showed a broad-spectrum antitumor effect in mice through inhibition of angiogenesis and indicate that the decrease of integrin alpha2 on platelets might serve as a biological marker for the antitumor efficacy of E7820. 相似文献
63.
Takashi Ueno Akira Tangoku Shigefumi Yoshino Toshihiro Abe Hideto Hayashi Hiroaki Toshimitsu Kiichiro Hashimoto Tomomitsu Satoh Atsunori Oga Tomoko Furuya Masaaki Oka Kohsuke Sasaki 《Clinical cancer research》2003,9(14):5137-5141
PURPOSE: Selection of appropriate protocols for treatment of superficial esophageal squamous cell carcinoma (SESCC) is dependent on lymph node metastasis status. Therefore, it is important to know whether lymph node metastasis is present before treatment. EXPERIMENTAL DESIGN: In this study, we examined the relation between DNA sequence copy number aberrations detected by comparative genomic hybridization and lymph node metastasis in 26 surgically resected SESCCs (training samples). We then assessed whether the genetic information is predictive for nodal status in biopsy specimens from eight newly enrolled patients with SESCC (blinded samples). RESULTS: Pathological examination revealed that 17 of 26 training samples (65.4%) did not have associated lymph node metastasis. Gains of 8q24 and/or 20q12-qter were observed in 12, including all (nine of nine) with nodal metastasis. Fourteen training samples did not have gain of either 8q24 or 20q12-qter. Of the blinded samples, two showed no gain of 8q24 or 20q12-qter, and as anticipated the postoperative pathological examination revealed no nodal metastasis. The remaining six blinded samples had gains of 8q24 and/or 20q12-qter, and lymph node metastasis was detected by postoperative examination in four of these tumors. CONCLUSIONS: Absence of gains of 8q24 and/or 20q12-qter appears to be associated with absence of lymph node metastasis in patients with SESCC; therefore, less invasive surgery can be chosen. 相似文献
64.
The expression of alternatively spliced mRNAs for amyloid precursor protein (APP) isoforms and their translation products were examined in the rat cerebral cortex 1, 3, 6, and 12 h and 1, 3, and 7 days (n = 4-5 in each group) after fluid-percussion brain injury. In situ hybridization studies demonstrated that the expression of APP695 mRNA decreased in and around the damaged area of the cerebral cortex exposed to fluid-percussion injury 1 h after the insult. On the other hand, APP751/770 mRNAs were increased in the regions surrounding the damaged cortical areas 1 day after the injury. An increase of immunoreactive APP was detected in the regions around the damaged cortical areas 3 h after traumatic injury and maintained for the following 3 days. The APP immunoreactivity in the damaged cortices declined to the level of sham-operated animals by post-experimental day 7. Using an anti-amyloid beta (Abeta) protein (17-24) antibody, no deposits of immunoreactive Abeta (17-24) were observed in any of the samples examined in these experiments. These results suggest that the induction of Kunitz-type protease inhibitor (KPI) domain-containing APP mRNAs and the increased accumulation of APP are involved in the physiological and neuropathological responses of brains under various neurodegenerative conditions, including head trauma. 相似文献
65.
A patient, who was not suited for ultrasound-guided biopsy, was biopsied in an interventional magnetic resonance unit at Brigham and Women's Hospital. Real-time magnetic resonance imaging provided verification of placement before tissue samples were taken. This technique successfully sampled tissue from the prostate and led to a diagnosis of cancer. 相似文献
66.
A child with facial abnormalities, short stature and a variety of skeletal alterations is reported. The facial abnormalities
comprised low-set ears, short nose with a long philtrum, micrognathia and cleft palate. The skeletal alterations included
ischial hypoplasia, malformations of the cervical spine, hypoplasia of the lesser trochanters, tibial hypoplasia with bowing
of the lower legs, tibio-fibular diastasis with malformed distal tibial epiphyses, clubfeet and brachymesophalangy. The constellation
of clinical and radiological findings in the present patient do not fit any known malformation syndrome.
Received: 14 February 1998 Accepted: 15 June 1998 相似文献
67.
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
68.
Konobu T Hata M Imanishi M Inada Y Murao Y Okuchi K Miyamoto S 《Kyobu geka. The Japanese journal of thoracic surgery》2000,53(12):1049-1051
A case of penetrating lung and diaphragmatic injuries with no abnormal findings of chest X-ray is reported. A 76-year-old man was admitted to our hospital due to penetrating chest trauma. A simple X-ray film of the chest on admission revealed no abnormal finding. An emergency operation was performed. On exploring the back open wound, we found a laceration of 7 cm in diameter in the right diaphragm and lung laceration. Then we repaired primarily with absorbable material. The postoperative course was uneventful, and the patient was discharged 12 days later. Penetrating truncal traumas can result in diaphragmatic injury. Sometimes the clinical and roentgenographic findings are unreliable. If the diagnosis is missed, a diaphragmatic injury may occur delayed diaphragmatic hernias within hours to years. Accordingly, initial wound exploration are important for the diagnosis of diaphragmatic injury in avoiding serious complications. 相似文献
69.
Shah AS White DC Tai O Hata JA Wilson KH Pippen A Kypson AP Glower DD Lefkowitz RJ Koch WJ 《The Journal of thoracic and cardiovascular surgery》2000,120(3):581-588
OBJECTIVES: Ex vivo perfusion of the cardiac allograft during organ procurement is an ideal environment for adenoviral vectors with transgenes that target improving graft contractility. One such target is the beta-adrenergic receptor-signaling system, in which alterations in transgenic mice have elucidated novel means to improve the function of the heart in vivo. The purpose of the current study was to determine the functional consequences of beta-adrenergic receptor manipulation in a rabbit model of cardiac allograft transplantation. METHODS: New Zealand White rabbits weighing 3 kg served as recipients to 1-kg outbred donors. Donor hearts were arrested and harvested, and 1 of 3 adenoviral constructs was administered into the aortic root perfusing the graft. Transgenes delivered encoded either the human beta(2)-adrenergic receptor, a peptide inhibitor of beta-adrenergic receptor densensitization, or the marker transgene beta-galactosidase. RESULTS: Five days after cervical heterotopic transplantation, left ventricular performance was measured on a Langendorff apparatus. A moderate pattern of rejection was seen in all grafts. Biventricular myocyte expression of beta-galactosidase was observed, and beta(2)-adrenergic receptor density was elevated 10-fold in grafts that received adeno-beta(2)-adrenergic receptor. Left ventricular systolic and diastolic performance was significantly increased in grafts transfected with either adeno-beta(2)-adrenergic receptor or adeno-beta-adrenergic receptor densensitization compared with control grafts that received adeno-beta-galactosidase. CONCLUSIONS: Ex vivo adenovirus-mediated gene transfer is feasible in a rabbit allograft model and, more important, genetic manipulation of beta-adrenergic receptor signaling either by increasing beta(2)-adrenergic receptor density or blocking endogenous receptor desensitization improves graft function acutely in this allograft model. 相似文献
70.
Ohno T Ikebuchi E Henomatsu K Kasai K Nakagome K Iwanami A Hiramatsu K Hata A Fukuda M Honda M Miyauchi M 《Psychiatry research》2000,100(3):155-167
Social skill deficits in schizophrenia profoundly affect patients' life-long outcome, although the profile of the underlying cognitive dysfunction still remains a matter of debate. In the present study, we investigated the relationship between social skills and event-related potentials (ERPs) in an auditory selective attention task, in addition to the neurocognitive indices obtained from the degraded-stimulus continuous performance test (CPT) and clinical indices, such as Brief Psychiatric Rating Scale (BRPS) and global assessment of function (GAF) scores. Social skills were assessed using a Japanese version of the structured role play test. Fourteen persons with schizophrenia participated in the study. Non-verbal skills showed a positive correlation with GAF, the performance level, N1 and N2b amplitude in the ERP task, and hit rate in the CPT, and a negative correlation with reaction time in the CPT. Verbal communication skills showed a positive correlation with GAF, the performance level and N2b amplitude in the ERP task, and hit rate in the CPT, and a negative correlation with reaction time in the CPT. Processing skills showed a positive correlation with the performance level and N1 amplitude in the ERP task and a negative correlation with reaction time in the CPT. These findings suggested that the social skill deficits of persons with schizophrenia were related to the vigilance level and controlled stimulus detection processing. 相似文献