全文获取类型
收费全文 | 16921篇 |
免费 | 1154篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 280篇 |
儿科学 | 440篇 |
妇产科学 | 445篇 |
基础医学 | 2547篇 |
口腔科学 | 453篇 |
临床医学 | 1768篇 |
内科学 | 3253篇 |
皮肤病学 | 296篇 |
神经病学 | 1508篇 |
特种医学 | 649篇 |
外国民族医学 | 1篇 |
外科学 | 2330篇 |
综合类 | 200篇 |
一般理论 | 51篇 |
预防医学 | 1405篇 |
眼科学 | 418篇 |
药学 | 1147篇 |
中国医学 | 16篇 |
肿瘤学 | 925篇 |
出版年
2023年 | 62篇 |
2022年 | 94篇 |
2021年 | 257篇 |
2020年 | 136篇 |
2019年 | 251篇 |
2018年 | 306篇 |
2017年 | 238篇 |
2016年 | 269篇 |
2015年 | 307篇 |
2014年 | 406篇 |
2013年 | 764篇 |
2012年 | 897篇 |
2011年 | 1080篇 |
2010年 | 589篇 |
2009年 | 508篇 |
2008年 | 917篇 |
2007年 | 989篇 |
2006年 | 901篇 |
2005年 | 921篇 |
2004年 | 968篇 |
2003年 | 868篇 |
2002年 | 928篇 |
2001年 | 182篇 |
2000年 | 149篇 |
1999年 | 189篇 |
1998年 | 235篇 |
1997年 | 201篇 |
1996年 | 177篇 |
1995年 | 163篇 |
1994年 | 159篇 |
1993年 | 138篇 |
1992年 | 129篇 |
1991年 | 117篇 |
1990年 | 121篇 |
1989年 | 126篇 |
1988年 | 114篇 |
1987年 | 115篇 |
1986年 | 92篇 |
1985年 | 114篇 |
1984年 | 114篇 |
1983年 | 104篇 |
1982年 | 165篇 |
1981年 | 133篇 |
1980年 | 132篇 |
1979年 | 82篇 |
1978年 | 90篇 |
1977年 | 81篇 |
1976年 | 70篇 |
1974年 | 75篇 |
1973年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
E. Skildebrand D. Heinegrd B. Olofsson G. Rucklidge N. Ronus S. Ekman 《Transboundary and Emerging Diseases》2006,53(9):445-449
This study evaluates how strenuous training, age and lameness influence the release of cartilage oligomeric matrix protein (sf‐COMP), aggrecan and collagen type II into synovial fluid in 28 (19.5–40 months) Standardbred trotters (STB), during a long‐term training programme (24 months). All the horses were trained by the same trainer and were healthy on entering the training programme. Synovial fluid (sf) from the left middle carpal joint in each subject was sampled every third month. Enzyme‐linked immunosorbent assay was used to determine the concentrations of sf‐COMP, sf‐aggrecan and sf‐collagen type II. Concentration of sf‐COMP decreased with increasing age and total days of training. The concentration of sf‐COMP was found similarly related to both age and total days of training, so they could not be differentiated. It was also shown that the concentration of collagen type II degradation products increased with total days of training. The study shows that extensive and long‐term training programme induces metabolic changes in articular cartilage exemplified by reduced release and synthesis of COMP. This is most likely due to strenuous training leading to inappropriate load on the articular cartilage. 相似文献
53.
Nir Giladi Babak Boroojerdi Amos D Korczyn David J Burn Carl E Clarke Anthony H V Schapira 《Movement disorders》2007,22(16):2398-2404
Rotigotine is a new, non-ergot dopamine agonist formulated in a transdermal delivery system. The present study was to investigate the efficacy and safety of the rotigotine transdermal patch in the treatment of early Parkinson's disease. Patients (n = 561) were randomized to rotigotine, ropinirole, or placebo. The titration period was up to 13 weeks, and there was a minimum dose-maintenance period of 24 weeks for ropinirole and 33 weeks for rotigotine. The primary endpoint was the proportion of patients with a minimum of 20% decrease in the combined Unified Parkinson's Disease Rating Scale Part II and Part III scores. The responder rate in the rotigotine group was significantly higher than in the placebo group (52% vs. 30%, P < 0.0001). Transdermal rotigotine at doses < or =8 mg/24 h did not show noninferiority to ropinirole at doses < or =24 mg/day. In a post-hoc subgroup analysis, rotigotine < or =8 mg/24 hours had a similar efficacy to ropinirole at doses < or =12 mg/day. The rotigotine transdermal patch was well tolerated. The most common adverse events were application-site reactions, nausea, and somnolence. Application-site reactions were predominantly mild or moderate in intensity. In conclusion, the rotigotine transdermal patch represents an effective and safe option for the treatment of patients with early Parkinson's disease. 相似文献
54.
55.
Kristin K Zorn Tomas Bonome Lisa Gangi Gadisetti V R Chandramouli Christopher S Awtrey Ginger J Gardner J Carl Barrett Jeff Boyd Michael J Birrer 《Clinical cancer research》2005,11(18):6422-6430
PURPOSE: The presence of similar histologic subtypes of epithelial ovarian and endometrial cancers has long been noted, although the relevance of this finding to pathogenesis and clinical management is unclear. Despite similar clinical characteristics, histologic subtypes of cancers of the ovary and endometrium are treated according to organ of origin. This study compares the gene expression profiles of analogous histologic subtypes of cancers of the ovary and endometrium using the same genomic platform to determine the similarities and differences between these tumors. EXPERIMENTAL DESIGN: Gene expression profiles of 75 cancers (endometrioid, serous, and clear cell) of the ovary and endometrium, five renal clear cell cancers, and seven normal epithelial brushings were determined using a 11,000-element cDNA array. All images were analyzed using BRB ArrayTools. Validation was done using real-time PCR on select genes and immunohistochemical staining. RESULTS: Comparison across endometrial and ovarian cancers and serous and endometrioid tumors showed expression patterns reflecting their organ of origin. Clear cell tumors, however, showed remarkably similar expression patterns regardless of their origin, even when compared with renal clear cell samples. A set of 43 genes was common to comparisons of each of the three histologic subtypes of ovarian cancer with normal ovarian surface epithelium. CONCLUSIONS: The comparison of the gene expression profiles of endometrioid and serous subtypes of ovarian and endometrial cancer are largely unique to the combination of a particular subtype in a specific organ. In contrast, clear cell cancers show a remarkable similarity in gene expression profiles across organs (including kidney) and could not be statistically distinguished. 相似文献
56.
57.
Parish P Sedghizadeh Derek Wong Charles F Shuler Vincent Linz John R Kalmar Carl M Allen 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(2):e30-e34
The calcifying epithelial odontogenic tumor (CEOT), or Pindborg tumor, is a rare and benign odontogenic neoplasm that affects the jaw. The most common manifestation of CEOT is a unifocal or localized lesion of the involved jaw, which may appear clinically as a hard tissue swelling and radiographically as a mixed radiolucent-radiopaque mass. In this article, we present a unique case of CEOT affecting multiple sites in the maxilla and mandible of a 51-year-old white man. Though biopsy samples from all involved sites revealed similar histopathologic features consistent with CEOT, the fact that there was a multifocal presentation is an unusual phenomenon for CEOT and has never been reported. Multifocal odontogenic lesions are not typical but have been observed in conditions associated with known genetic mutations. For example, multiple odontogenic keratocysts are the most common feature of the inherited condition known as nevoid basal cell carcinoma syndrome. This case, however, is the first one to demonstrate that there may be a multifocal variant of CEOT that has not been previously recognized. 相似文献
58.
Brian Trappler Carl I Cohen Rajeshree Tulloo 《The American journal of geriatric psychiatry》2007,15(1):79-83
RATIONALE: Holocaust survivors, who experienced trauma 60 years ago, provide an opportunity to explore the impact of early lifetime trauma in later life and, in particular, the interplay of depression and posttraumatic stress disorder (PTSD). In this study, the authors contrast depressed Holocaust survivors (HD), nondepressed Holocaust survivors (HND), and older depressed persons (CD). METHODS: The sample consisted of 36 consecutive Holocaust survivors (mean age: 79 years) treated in a primary care practice, among whom 20 (56%) were diagnosed as having a major depressive disorder and 16 as nondepressed; 18 depressed non-Holocaust Jewish primary care patients served as controls (mean age: 84 years). The authors examined nine clinical and social variables. The Kruskal-Wallis, Mann-Whitney U, and chi(2) tests were used to contrast the groups. The authors used a conservative significance level of .01. RESULTS: In contrast to the CD group, the HD group was significantly older, more likely to report PTSD and guilt symptoms, to have higher Beck Anxiety Inventory (BAI) and Brief Psychiatric Rating Scale (BPRS) scores, and to have more impaired social functioning. In contrast to the HND group, the HD group was significantly more likely to report PTSD and guilt feelings, to have higher Hamilton Depression Scale (HAM-D), BAI, and BPRS scores, and to have more impaired social functioning. In contrast to the CD group, the HND group was significantly more likely to have PTSD symptoms and to have lower HAM-D and BPRS scores. CONCLUSIONS: The prevalence of depression and PTSD symptoms were very high among survivors. Depressed survivors had significantly worse psychologic and social functioning than depressed controls. Depressed survivors had more PTSD symptoms than nondepressed survivors, although it is unclear as to the causal direction of the relationship between depression and PTSD. 相似文献
59.
60.
Vanessa Vu J. Carl Barrett Joseph Roycroft Loretta Schuman David Dankovic Paul BBaro Ted Martonen William Pepelko David Lai 《Regulatory toxicology and pharmacology : RTP》1996,24(3):202-212
On May 8–10, 1995, a workshop on chronic inhalation toxicity and carcinogenicity testing of respirable fibrous particles was held in Chapel Hill, North Carolina. The workshop was sponsored by the Office of Pollution Prevention and Toxics, U.S. Environmental Protection Agency (EPA), in collaboration with the National Institute of Environmental Health Sciences (NIEHS), the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). The goal of the workshop was to obtain input from the scientific community on a number of issues related to fiber testing. Major issues for discussion were: (i) the optimal design and conduct of studies of the health effects of chronic inhalation exposure of animals to fibers; (ii) preliminary studies which would be useful guides in designing the chronic exposure study; (iii) mechanistic studies which would be important adjuncts to the chronic exposure study to enable better interpretation of study results and extrapolation of potential effects in exposed humans; and (iv) available screening tests which can be used to develop a minimum data set for (a) making decisions about the potential health hazard of the fibers and (b) prioritizing the need for further testing in a chronic inhalation study. After extensive discussion and debate of the workshop issues, the general consensus of the expert panel is that chronic inhalation studies of fibers in the rat are the most appropriate tests for predicting inhalation hazard and risk of fibers to humans. A number of guidances specific for the design and conduct of prechronic and chronic inhalation studies of fibers in rodents were recommended. For instance, it was recommended that along with other information (decrease in body weight, systemic toxicity, etc.), data should be obtained on lung burdens and bronchoalveolar lavage fluid analysis to assist in establishing the chronic exposure levels. Lung burden data are also important for quantifying aspects of risk assessment related to dosimetric adjustments before extrapolation. Although mechanistic studies are not recommended as part of the standard chronic inhalation studies, the expert panel stressed the need for obtaining mechanistic information as far as possible during the course of subchronic or chronic inhalation studies. At present, no single assay and battery of short-term assays can predict the outcome of a chronic inhalation bioassay with respect to carcinogenic effects. Meanwhile, several short-termin vitroandin vivostudies that may be useful to assess the relative potential of fibrous substances to cause lung toxicity/carcinogenicity have been identified. 相似文献