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   64257篇
  免费   4695篇
  国内免费   183篇
耳鼻咽喉   830篇
儿科学   1806篇
妇产科学   1599篇
基础医学   10546篇
口腔科学   1706篇
临床医学   6093篇
内科学   12893篇
皮肤病学   984篇
神经病学   6028篇
特种医学   2833篇
外国民族医学   45篇
外科学   8245篇
综合类   554篇
一般理论   84篇
预防医学   5000篇
眼科学   1214篇
药学   4627篇
中国医学   163篇
肿瘤学   3885篇
  2022年   378篇
  2021年   1039篇
  2020年   654篇
  2019年   932篇
  2018年   1143篇
  2017年   795篇
  2016年   930篇
  2015年   1105篇
  2014年   1350篇
  2013年   2354篇
  2012年   3023篇
  2011年   3103篇
  2010年   2273篇
  2009年   1902篇
  2008年   2812篇
  2007年   2957篇
  2006年   2941篇
  2005年   2799篇
  2004年   2844篇
  2003年   2583篇
  2002年   2654篇
  2001年   2178篇
  2000年   2226篇
  1999年   2007篇
  1998年   921篇
  1997年   777篇
  1996年   692篇
  1995年   700篇
  1994年   595篇
  1993年   638篇
  1992年   1458篇
  1991年   1409篇
  1990年   1344篇
  1989年   1344篇
  1988年   1144篇
  1987年   1122篇
  1986年   1063篇
  1985年   989篇
  1984年   698篇
  1983年   650篇
  1982年   465篇
  1981年   449篇
  1980年   387篇
  1979年   629篇
  1978年   380篇
  1977年   363篇
  1975年   377篇
  1974年   416篇
  1973年   348篇
  1972年   340篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Occupational disease surveillance data sources, 1985.   总被引:1,自引:1,他引:0       下载免费PDF全文
Health department epidemiologists in 50 states, New York City, and the District of Columbia were surveyed in 1985 about seven potential data sources for occupational disease surveillance. Reported sources of occupational disease data were: automated workers' compensation claims (63 per cent of the 52 respondents); provider reports (62 per cent); death certificates with occupation or industry (60 per cent); cancer registries with occupational histories (35 per cent); birth certificates with parent's occupation (27 per cent); non-cancer disease registries (13 per cent); and hospital or insurance records (8 per cent).  相似文献   
92.
93.
BACKGROUND: Vitiligo is the most common pigmentary disorder with a global incidence from 0.1% to 2% in different geographical areas. Histopathology and histochemistry have shown the reduction of melanocytes in achromic patches, but microscopic changes of lesional and non-lesional skin are still not completely understood. Reflectance confocal microscopy (RCM), based on the different light reflectance index of cutaneous structures, allowed in vivo, en face microscopic evaluation of superficial skin layers with a resolution similar to skin histology. AIM: The purpose of this study was to evaluate RCM features of lesional and non-lesional skin of vitiligo patients. Moreover, re-pigmented areas were taken into consideration in order to evaluate melanocyte response to ultraviolet B (UVB) radiation. SUBJECTS AND METHODS: Sixteen patients of different phototypes affected by active non-segmental vitiligo and 10 controls were enrolled in the study. In vivo skin imaging was done using a commercially available RCM (Lucid, Vivascope 1500. Re-pigmented areas from 6 to 16 patients (after UVB narrow-band therapy) were also examined. RESULTS: Vitiligo lesions showed the disappearance of the bright rings normally seen at the dermo-epidermal junction. Moreover, non-lesional skin of vitiligo patients showed unexpected changes as the presence of half-rings or scalloped border-like features of the bright papillary rings. In re-pigmented areas after UVB narrow band therapy, the presence of activated, dendritic melanocytes was seen. CONCLUSIONS: Considering our results, and following further studies, RCM clinical applications could be used in the therapeutic monitoring and evaluation of the evolution of vitiligo.  相似文献   
94.
In France, general practitioners (GPs) express difficulties in exercise of home palliative care. Those difficulties are described in various studies but none assesses the multidisciplinary collaboration’s impact. In the present study (2005–2008), 291 GPs included in a palliative care network responded to a questionnaire. Results showed the benefits of this partnership organization. Detailed analysis of 36 collaboration cases clarified the reasons for these difficulties and the network influence.  相似文献   
95.
96.
The alpha-chloroether carcinogen chloromethylmethyl ether (CME) and its impurity bis(chloromethyl)ether (BCME) are direct-acting alkylating agents. Vinyl chloride (VC) is an indirect-acting carcinogen but its accepted carcinogenic intermediate, chloroethylene oxide, is also an alpha-chloroether. Both CME-BCME and VC have been in industrial use since about 1950. Hence, they were selected for comparison of potency as human carcinogens using numerous epidemiologic reports. There were 115 deaths due to angiosarcoma of the liver among several hundred thousand VC-exposed workers on the basis of reports from 10 countries during 1955 and 1984. Reports from five countries cited a total of 87 respiratory cancer deaths among only 3024 CME-BCME-exposed workers. If a recent court settlement in the United States is taken into account, the number of respiratory cancer deaths due to CME-BCME rises to 117. On the basis of these numbers of cancer deaths, and the levels and durations of exposure, it is concluded that VC is a weak human carcinogen compared to CME-BCME.  相似文献   
97.
Double-outlet right ventricle and severe systemic outflow tract hypoplasia comprises a subset of patients in whom total correction or palliation requires complex surgical procedures in the neonatal period. Our experience with 3 patients illustrates the difficulties associated with treatment and suggests possible surgical options for this otherwise lethal variant of the Taussig-Bing syndrome.  相似文献   
98.
A training program was implemented to modify a mother's behavior management skills to improve compliance in her 4-year-old child who suffered from severe developmental and physical disabilities. A multiple baseline analysis indicated that behavioral intervention was effective in training the mother to make definitive commands, provide appropriate positive attention, and persist with commands during social interactions with her child. In addition, substantial improvement in the child's compliance with mother's commands followed introduction of parent training. Further, positive collateral effects included the child's increased time on-task and decreased oppositional behavior. All gains were maintained at a 6-month follow-up probe.  相似文献   
99.
Patients with complaints of halitosis do seek treatment from physicians and dental practitioners, because of the fear that their halitosis may interfere with their social activities. Although the prevalence of halitosis has been reported to be as high as 50%, most physicians and dental practitioners are poorly informed about the causes and treatments of halitosis. In order to care for patients with complaints of halitosis a multidisciplinary team was established at the Erasmus Medical Centre, Rotterdam, The Netherlands. The team included a dental hygienist, an otorhinolaryngologist, and a dentist, who developed a special halitosis programme. One short press release regarding the establishment of the team, was provided to the national press-centre. In the out-patient clinic more than 700 patients were seen by the team. Using a structured questionnaire fed to a PC, patients answered questions regarding complaints about the oral cavity, the upper respiratory tract, the throat, their general health, their cleansing habits of the oral cavity, and prior experiences with general physicians, dental practitioners, and medical specialists. They underwent examinations of the extent of their halitosis, of the perioral and neck region, the oral cavity, the upper respiratory tract, and the upper digestive tract. Finally, the members of the team came to a joint diagnosis and a joint treatment plan for every individual patient. Of the first 700 consecutive patients around 90% had a natural dentition without removable partial dentures. More than 60% were diagnosed as having periodontal disease with pockets of 4 mm or more in the maxilla. This figure was more than 50% in the mandible. Around 95% had tongue coating.  相似文献   
100.
Kollicoat IR, a new pharmaceutical excipient developed as a coating polymer for instant release tablets, was evaluated as a carrier in solid dispersions of Itraconazole. The solid dispersions were prepared by hot stage extrusion. Modulated temperature differential scanning calorimetry and X-ray powder diffraction were used to evaluate the miscibility of the drug and the carrier. The pharmaceutical performance was evaluated by dissolution experiments, performed in simulated gastric fluid without pepsin (SGF(sp)). In the X-ray diffractograms no Itraconazole peaks were visible; the polymer on the other hand appeared to be semi-crystalline. Moreover, its crystallinity increased during the extrusion process due to exposure to heat and shear forces. Modulated temperature differential scanning calorimetry analysis showed that the drug and the polymer formed a two phase system. Separate clusters of glassy Itraconazole were present for drug loads of 40% or higher, indicating further phase separation. Dissolution measurements demonstrated a significantly increased dissolution rate for the solid dispersions compared to physical mixtures. Interestingly the physical mixture made up of glassy Itraconazole and Kollicoat IR (20/80, w/w) showed a dissolution rate and maximum that was much higher than that of the physical mixture made up of crystalline Itraconazole and that of pure glassy Itraconazole. The results of this study show that Kollicoat IR is a promising excipient for the formulation of solid dispersions of Itraconazole prepared by hot stage extrusion.  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