首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1561篇
  免费   112篇
  国内免费   2篇
耳鼻咽喉   41篇
儿科学   47篇
妇产科学   22篇
基础医学   253篇
口腔科学   10篇
临床医学   148篇
内科学   258篇
皮肤病学   28篇
神经病学   192篇
特种医学   93篇
外科学   114篇
综合类   10篇
一般理论   6篇
预防医学   158篇
眼科学   19篇
药学   132篇
中国医学   1篇
肿瘤学   143篇
  2023年   14篇
  2022年   25篇
  2021年   55篇
  2020年   37篇
  2019年   32篇
  2018年   46篇
  2017年   35篇
  2016年   35篇
  2015年   43篇
  2014年   49篇
  2013年   66篇
  2012年   91篇
  2011年   120篇
  2010年   54篇
  2009年   54篇
  2008年   98篇
  2007年   75篇
  2006年   92篇
  2005年   70篇
  2004年   96篇
  2003年   73篇
  2002年   75篇
  2001年   23篇
  2000年   21篇
  1999年   8篇
  1998年   17篇
  1997年   10篇
  1996年   14篇
  1995年   11篇
  1994年   7篇
  1993年   14篇
  1992年   14篇
  1991年   10篇
  1990年   13篇
  1989年   12篇
  1988年   14篇
  1987年   7篇
  1986年   14篇
  1985年   6篇
  1983年   10篇
  1982年   8篇
  1981年   12篇
  1980年   7篇
  1978年   6篇
  1977年   11篇
  1975年   9篇
  1973年   5篇
  1968年   6篇
  1967年   4篇
  1963年   4篇
排序方式: 共有1675条查询结果,搜索用时 15 毫秒
81.
Embolia cutis medicamentosa, also known as Nicolau’s syndrome, is a rare complication due to i.m. injections. Its real incidence is actually underestimated. Many drugs have been associated with it, but at the time only a few studies showed a related pathogenetic mechanism. Symptoms consist of immediate local pain, edema and cutaneous, subcutaneous and even muscular necrosis occurring in the first 48 h. The type of treatment depends mostly on time of diagnosis. A medical resolution can be achieved through heparin and cortisone injections within the first 48 h. Surgical debridement has to be considered as the main treatment in case of late diagnosis. We present three cases of Nicolau’s syndrome presenting to us in a short period of time that we treated with surgical debridement.  相似文献   
82.
The dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) in terms of toxic equivalents (TEQs) was investigated in Swedish children and young adults. Exposure was estimated from concentration data of six groups of individual food commodities (meat, fish, dairy products, egg, edible fats and other foodstuff) combined with food intake data from a 7-day record book obtained from 670 individuals aged 1–24 years. The results showed that Swedish boys and girls, up to the age of ten, had a median TEQ intake that exceeded the tolerable daily intake (TDI) of 2 pg TEQ/kg body weight. Children exceeding the TDI varied from almost all individuals among the youngest children to about 20% among young men and women. Dairy and fish products were the main sources of exposure for the average child, accounting for 59% of the total TEQ intake. The individuals most highly exposed were, on the other hand, characterized by a high consumption of fish. Since children constitute a vulnerable group, results obtained from the present study show that it is essential to perform age specific dietary intake assessments of pollutants and more carefully consider sensitive and/or highly exposed groups in the population in the risk management processes.  相似文献   
83.

Background  

There is at present a lack of knowledge of time trends in health related quality of life (HRQL) in common patients with coronary artery disease (CAD) treated in ordinary care. The objective of this study is to assess and compare time trends of health related quality of life (HRQL) and chest pain in patients with coronary artery disease.  相似文献   
84.
Hypotonic swelling of teleost erythrocytes activates multiple transport systems leading to the regulatory decrease of cell volume. We have examined using pharmacological manipulation the swelling-induced taurine flux pathway in red blood cells of the rainbow trout and its relationship to swelling-induced K flux pathways. We show that the activation and deactivation of taurine flux is rapid and that the flux is a sigmoidal function of cell volume. N-ethylmaleimide (NEM) and the non-specific protein kinase inhibitor, staurosporine, both inactivated the hypotonically-induced taurine flux with concentrations eliciting half-maximal inhibition (IC50s) of 212 and 17 micromol(-1), respectively. The low taurine fluxes under isotonic conditions were unaffected. By contrast, the tyrosine kinase inhibitor, genistein, partially inhibited taurine flux under both isotonic and hypotonic conditions. The specific phosphatase inhibitor, calyculin A, had no inhibitory or stimulatory effect under either condition whilst the less-specific phosphatase inhibitor, ortho-vanadate, reduced taurine flux only under hypotonic conditions. In these respects the regulatory control of the taurine pathway differs from the Cl-dependent K flux. However, NEM and staurosporine also inhibited the Cl-independent K flux, both with similar IC50s to those observed for taurine fluxes. This supports the idea of the hypotonically-induced taurine flux and the Cl-independent K flux sharing the same transport pathway.  相似文献   
85.
This paper reports on the clinical evaluation of a commercially available head-worn programmable 3-channel automatic gain control (AGC) hearing instrument (Siemens, Triton 3000). A preliminary fitting procedure is developed for the 3-channel AGC amplification system, which is compared by 26 experienced hearing instrument wearers with their own single-channel AGC instruments. The benefits of both amplification systems are assessed by speech audiometry at different signal-to-noise ratios utilizing German rhyme test speech material. In addition, subjective judgements concerning sound quality, speech intelligibility and comparison with the subject's own instrument are evaluated. The results indicate that the multichannel compression instrument is superior to single-channel aids in competitive speech situations. If the 3-channel AGC instrument is used as an automatic noise reduction system in patients requiring a certain amount of low-frequency gain, a markedly better speech recognition can be achieved compared to the subject's personal aids.  相似文献   
86.
87.
Identification of TAAs recognized by CD8(+) CTLs paved the way for new concepts in cancer therapy. In view of the heterogeneity of tumors and their diverse escape mechanisms, CTL-based cancer therapy largely depends on an appropriate number of TAAs. In prostate cancer, the number of antigens defined as suitable targets of CTLs remains rather limited. PSCA is widely distributed in prostate cancer. In this report, we define immunogenic peptides of PSCA which are recognized by circulating CD8(+) T cells from prostate cancer patients and able to activate CTLs in vitro. Screening the amino acid sequence of PSCA for peptides containing a binding motif for HLA-A*0201 resulted in 8 candidate peptides. Specificity and affinity of peptide binding were verified in a competition assay. Frequencies of CD8(+) T lymphocytes reactive against selected epitopes were determined in the blood of prostate cancer patients using the ELISPOT assay. Increased frequencies were revealed for CD8(+) T cells recognizing the peptides ALQPGTALL and AILALLPAL. CTLs from prostate cancer patients were raised against these 2 peptides in vitro when presented by autologous DCs. They specifically recognized peptide-pulsed T2 target cells and prostate cancer cells that were HLA-A*0201- and PSCA-positive, indicating that these peptides were naturally generated by tumor cells. These data suggest that PSCA is a promising target for the immunotherapy of prostate cancer.  相似文献   
88.
Purpose: To evaluate changes in distribution of hepatic arterial blood flow in the liver following insertion of an uncovered stent and subsequently a stent-graft in the transjugular intrahepatic portosystemic shunt (TIPS) channel. Methods: The experiments were performed in eight healthy pigs under general anesthesia. In a pilot study in one pig, scintigraphic evaluation of arterial perfusion to the liver was done before and after inflation of a balloon in the right hepatic vein. In the other pigs, outflow from the right liver vein was checked repeatedly by contrast injection through a percutaneously inserted catheter. The arterial perfusion through the liver was examined by scintigraphy, following selective injection of macro-aggregate of 99Tc m-labeled human serum albumin 99Tc m-HSA) into the hepatic artery. This examination was done before and after creation of a TIPS with an uncovered stent and subsequently after insertion of a covered stent-graft into the cranial portion of the shunt channel. Results: In the pilot study changes in the arterial perfusion to the liver were easily detectable by scintigraphy. One pig died during the procedure and another pig was excluded due to dislodgement of the hepatic artery catheter. The inserted covered stent obstructed venous outflow from part of the right liver lobe. The 99Tc m-HSA activity in this part remained unchanged after TIPS creation with an uncovered stent. A reduction in activity was seen after insertion of a stent-graft (p= 0.06). Conclusion: The distribution of the hepatic arterial blood flow is affected by creation of a TIPS with a stent-graft, in the experimental pig model.  相似文献   
89.
Background: Titanium spine implants are well established materials in posterior spondylodesis. The biocompatibility of a semirigid tivanium cable suitable for pedicle screws in posterior spinal fusion (DDS-Plus?) was tested by a human bone marrow cell culture. In comparison to the tivanium cable implant (Ti6Al4V; DDS-Plus?), hydroxyapatite (HA), commercially pure titanium (cpTi), glass, chromium-cobalt alloy, (CrCoMo), polyaryletherketon (PAEK) and polyethylene (UHMW-PE) were tested. Materials and Methods: Scanning electron microscopy (SEM), SEM-energy dispersive X-ray analysis (SEM-EDX), fluorescent activated cell sorter (FACS), immunohistochemical techniques, light microscopy (LM) and immunochemical extracellular matrix analysis served to judge the in vitro biocompatibility of the different implants in a human bone marrow cell culture. Results: The datas of this investigation point out that the tivanium cable is equally biocompatible to commercially pure titanium and showed less signs of cytotoxicity than the other tested materials in vitro. Beside the titanium alloys, HA showed a high degree of biocompatibility compated to the polymers and CrCoMo too. Conclusions: In respect to their in vitro biocompatibility, the semirigid tivanium spine cable could be an alternative for other systems for posterior spondylodesis. Biomechanical and clinical studies are necessary to improve these datas. Received: March 29, 2002; revision accepted: September 30, 2002 Correspondence Address Marcus J?ger, MD, Department of Orthopedics, Heinrich Heine University, 40225 Duesseldorf, Moorenstra?e 5, Germany, Phone (+49/211) 8117960, Fax (+49/202) 9422623, e-mail: drjaegermarcus@yahoo.de  相似文献   
90.
In all, 19 research subjects, with current histories of frequent cocaine use, were exposed to cocaine-related cues to elicit drug craving. We measured the change of occupancy of dopamine at D2-like receptors with positron emission tomography (PET) and inferred a change of intrasynaptic dopamine (endogenous dopamine release), based on the displacement of radiotracer [(11)C]raclopride. Receptor occupancy by dopamine increased significantly in putamen of participants who reported cue-elicited craving compared to those who did not. Further, the intensity of craving was positively correlated with the increase in dopamine receptor occupancy in the putamen. These results provide direct evidence that occupancy of dopamine receptors in human dorsal striatum increased in proportion to subjective craving, presumably because of increased release of intrasynaptic dopamine.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号