全文获取类型
收费全文 | 252151篇 |
免费 | 17828篇 |
国内免费 | 1130篇 |
专业分类
耳鼻咽喉 | 2787篇 |
儿科学 | 6499篇 |
妇产科学 | 4601篇 |
基础医学 | 32965篇 |
口腔科学 | 4557篇 |
临床医学 | 25343篇 |
内科学 | 53624篇 |
皮肤病学 | 3387篇 |
神经病学 | 24277篇 |
特种医学 | 8398篇 |
外国民族医学 | 11篇 |
外科学 | 38464篇 |
综合类 | 3457篇 |
一般理论 | 318篇 |
预防医学 | 21412篇 |
眼科学 | 6569篇 |
药学 | 16983篇 |
6篇 | |
中国医学 | 361篇 |
肿瘤学 | 17090篇 |
出版年
2023年 | 1340篇 |
2022年 | 2411篇 |
2021年 | 5440篇 |
2020年 | 3266篇 |
2019年 | 5302篇 |
2018年 | 5950篇 |
2017年 | 4471篇 |
2016年 | 4959篇 |
2015年 | 5828篇 |
2014年 | 8604篇 |
2013年 | 11801篇 |
2012年 | 18011篇 |
2011年 | 18901篇 |
2010年 | 10577篇 |
2009年 | 9428篇 |
2008年 | 16601篇 |
2007年 | 17453篇 |
2006年 | 17307篇 |
2005年 | 17280篇 |
2004年 | 16191篇 |
2003年 | 15042篇 |
2002年 | 14055篇 |
2001年 | 2110篇 |
2000年 | 1600篇 |
1999年 | 2318篇 |
1998年 | 3066篇 |
1997年 | 2562篇 |
1996年 | 2183篇 |
1995年 | 2096篇 |
1994年 | 1745篇 |
1993年 | 1571篇 |
1992年 | 1263篇 |
1991年 | 1151篇 |
1990年 | 999篇 |
1989年 | 981篇 |
1988年 | 969篇 |
1987年 | 949篇 |
1986年 | 954篇 |
1985年 | 968篇 |
1984年 | 1221篇 |
1983年 | 1125篇 |
1982年 | 1366篇 |
1981年 | 1313篇 |
1980年 | 1146篇 |
1979年 | 703篇 |
1978年 | 749篇 |
1977年 | 638篇 |
1976年 | 585篇 |
1975年 | 469篇 |
1974年 | 474篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Takashi Takata Yong Lu Ikuko Ogawa Ming Zhao Zhi Yu Zhou David Mock Hiromasa Nikai 《Pathology international》1998,48(11):877-881
The calcifying odontogenic cyst (COC) presents with diverse hlstologlcal features; thus, several subclasslfl-cations have been proposed. To evaluate the slgnlficance of the various histological features and subtypes of COC from the perspectlve of proliferative activity, the proliferating cell nuclear antigen (PCNA) labellng index (LI; the percentage of positive nuclei) was assessed immunohistochemlcally in 25 cases of COC (21 benign and four malignant). All of the benign cases were of the cystic variety and further subclas-sified into non-proliferative subtype (NPS; four cases); proliferative subtype (PS; eight cases); and COC associated with odontoma (COCaO, nlne cases). The PCNA U of the mallgnant COC (65.2 ± 5.6) was slgnlflcantly higher than that of the benlgn COC (11.6 ± 9.0; P = 0.002). Non-proliferative subtype (6.8 ± 2.8) showed the lowest PCNA LI and PS (17.2 ± 11.2) the highest of among the three subtypes of benign cystic COC (P = 0.028). In nine cases of COCaO, six showed epithelial lining of the non-proliferative type as NPS and the other three had lining wlth proliferative features as PS. The PCNA LI of the latter COCaO group (14.3 ± 6.6) was significantly higher than that of the former (6.1 ± 4.3; P = 0.05), as Seen between PS and NPS. These results demonstrate that PCNA LI is a possible parameter for differentiating mallgnant COC from benign COC and, whatever the subtypes, the proliferative features In the lining are the main factor influencing the prollferatlng actlvity of COC. 相似文献
992.
Daniel Chripko Joan C. Bevan David P. Archer Nicole Bherer 《Journal canadien d'anesthésie》1989,36(2):128-132
Arterial oxygen saturation was measured by pulse oximetry in two groups of paediatric outpatients breathing room air during transport from the operating room to the postanaesthetic recovery room. In Group I (n = 60) readiness for transfer from OR to PARR was decided clinically. In Group II (n = 50) additional criteria of oxygen saturation (SaOe) greater than or equal to 98 per cent with end-tidal gas N2O less than or equal to 10 per cent and CO2 less than or equal to 45 mmHg were met. A higher incidence of desaturation (SaO2 less than or equal to 90 per cent) occurred in Group I (27 per cent) than in Group II (eight per cent) (P less than 0.05). More children under 2 yr desaturated in Group I (50 per cent) than Group II (17 per cent) (P greater than 0.05 less than 0.10). Twenty-two patients in each group had a recent history of upper respiratory tract infections. In these patients, desaturation was more marked in those in Group I (32 per cent) than in Group II (five per cent) (P less than 0.05). Within each group, the incidence of desaturation during transport was similar in patients with or without a recent URI. 相似文献
993.
994.
995.
Fanasy P. Deming Ibtisam Al-Hashimi Nasser Haghighat William W. Hallmon David G. Kerns Celeste Abraham Francisco Rivera-Hidalgo 《Journal of oral pathology & medicine》2007,36(3):132-135
Background: Reduction in salivary secretion is the hallmark of Sjögren's syndrome (SS). Calmodulin (CaM) and calmodulin binding proteins (CaMBPs) play a key role in the secretory process of saliva. Recent studies have suggested that SS‐B, an autoantibody associated with SS, is a CaMBP. This finding suggests that CaMBP may contribute to the loss of saliva in SS. To better understand the role(s) of these proteins in SS, the purpose of this study was to compare salivary CaMBPs in Sjögren's patients and controls. Methods: Saliva samples were collected from 20 patients and 20 age‐, race‐, and gender‐matched controls. CaM overlay was used to identify CaMBPs in saliva of patients and controls. Results: Higher number of salivary CaMBPs was observed among patients than controls. Conclusions: The increased number of salivary CaMBPs in SS may suggest a potential role for these proteins in the pathogenesis of the disease. 相似文献
996.
Two cases of staphylococcal lung disease in young infants are described. In each instance a life-threatening bronchopleural fistula in the acute phase was successfully managed by thoracotomy and suture repair.
Offprint requests to: A. W. Auldist 相似文献
997.
The induction of antibody response in syngeneic rats by the Gross virus cell surface antigen (GCSAa) was dependent on the presentation of GCSAa into liposomes made from distearoylphosphatidylcholine (DSPC). GCSAa liposomes made from dimyristoylphosphatidylethanolamine (DMPE) were nonimmunogenic, even when used as anamnestic immunogens. Spleen cells, from rats twice immunized with GCSAa-DSPC-liposomes and used to transfer the anti-GCSAa immune response into naive recipients after a tertiary immunostimulation in vitro in the presence of naive peritoneal exudate cells (PEC), responded to soluble GCSAa only after irradiation at 500 rds and to GCSAa-DMPE-liposomes only when indomethacin was added during the in vitro stimulation. The preincubation of these cells with empty DMPE liposomes or the addition of supernatant from PEC fed with DMPE liposomes abrogated the response to GCSAa-DSPC liposomes. Using a specific radioimmunoassay, prostaglandin E2 was demonstrated to be produced by PEC when fed with DMPE liposomes, and not when fed with DSPC liposomes. This prostaglandin E2 secretion by PEC induced by DMPE liposomes was inhibited by indomethacin. 相似文献
998.
Thyroid gland: US in patients with Hodgkin disease treated with radiation therapy in childhood 总被引:1,自引:0,他引:1
The authors retrospectively assessed with sonography the prevalence of thyroid gland abnormalities in 30 patients who underwent radiation therapy for Hodgkin disease between 1962 and 1984. Doses ranged from 3,000 to 4,500 rad (3,000-4,500 cGy). Abnormalities were found in the sonograms of 24 patients and included unilateral (n = 6) or bilateral (n = 2) atrophy; multiple hypoechoic lesions smaller than 0.75 cm (n = 18); and dominant cystic (n = 2), solid (n = 3), or complex lesions (n = 4) larger than 0.75 cm. The risk of development of an abnormality increased as the time from irradiation increased and was comparable between patients who did and did not receive chemotherapy as part of the treatment regimen. Although the pathologic correlates of the various abnormalities seen on sonograms may differ, the findings indicate a need for long-term follow-up of patients who underwent cervical irradiation for Hodgkin disease. 相似文献
999.
The use of item banks and computerized adaptive testing (CAT) begins with clear definitions of important outcomes, and references those definitions to specific questions gathered into large and well-studied pools, or “banks” of items. Items can be selected from the bank to form customized short scales, or can be administered in a sequence and length determined by a computer programmed for precision and clinical relevance. Although far from perfect, such item banks can form a common definition and understanding of human symptoms and functional problems such as fatigue, pain, depression, mobility, social function, sensory function, and many other health concepts that we can only measure by asking people directly. The support of the National Institutes of Health (NIH), as witnessed by its cooperative agreement with measurement experts through the NIH Roadmap Initiative known as PROMIS (www.nihpromis.org), is a big step in that direction. Our approach to item banking and CAT is practical; as focused on application as it is on science or theory. From a practical perspective, we frequently must decide whether to re-write and retest an item, add more items to fill gaps (often at the ceiling of the measure), re-test a bank after some modifications, or split up a bank into units that are more unidimensional, yet less clinically relevant or complete. These decisions are not easy, and yet they are rarely unforgiving. We encourage people to build practical tools that are capable of producing multiple short form measures and CAT administrations from common banks, and to further our understanding of these banks with various clinical populations and ages, so that with time the scores that emerge from these many activities begin to have not only a common metric and range, but a shared meaning and understanding across users. In this paper, we provide an overview of item banking and CAT, discuss our approach to item banking and its byproducts, describe testing options, discuss an example of CAT for fatigue, and discuss models for long term sustainability of an entity such as PROMIS. Some barriers to success include limitations in the methods themselves, controversies and disagreements across approaches, and end-user reluctance to move away from the familiar. 相似文献
1000.