全文获取类型
收费全文 | 23420篇 |
免费 | 1640篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 303篇 |
儿科学 | 709篇 |
妇产科学 | 426篇 |
基础医学 | 2880篇 |
口腔科学 | 641篇 |
临床医学 | 2525篇 |
内科学 | 4339篇 |
皮肤病学 | 326篇 |
神经病学 | 2197篇 |
特种医学 | 774篇 |
外科学 | 3838篇 |
综合类 | 314篇 |
一般理论 | 20篇 |
预防医学 | 2024篇 |
眼科学 | 477篇 |
药学 | 1839篇 |
中国医学 | 19篇 |
肿瘤学 | 1480篇 |
出版年
2023年 | 114篇 |
2022年 | 189篇 |
2021年 | 503篇 |
2020年 | 278篇 |
2019年 | 501篇 |
2018年 | 578篇 |
2017年 | 402篇 |
2016年 | 419篇 |
2015年 | 502篇 |
2014年 | 773篇 |
2013年 | 1045篇 |
2012年 | 1673篇 |
2011年 | 1636篇 |
2010年 | 916篇 |
2009年 | 837篇 |
2008年 | 1526篇 |
2007年 | 1528篇 |
2006年 | 1560篇 |
2005年 | 1525篇 |
2004年 | 1433篇 |
2003年 | 1233篇 |
2002年 | 1176篇 |
2001年 | 298篇 |
2000年 | 290篇 |
1999年 | 303篇 |
1998年 | 264篇 |
1997年 | 204篇 |
1996年 | 174篇 |
1995年 | 161篇 |
1994年 | 155篇 |
1993年 | 148篇 |
1992年 | 172篇 |
1991年 | 176篇 |
1990年 | 174篇 |
1989年 | 152篇 |
1988年 | 165篇 |
1987年 | 151篇 |
1986年 | 122篇 |
1985年 | 119篇 |
1984年 | 132篇 |
1983年 | 120篇 |
1982年 | 104篇 |
1981年 | 109篇 |
1980年 | 86篇 |
1979年 | 91篇 |
1978年 | 86篇 |
1977年 | 69篇 |
1975年 | 68篇 |
1974年 | 64篇 |
1973年 | 78篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Sinusitis is one of the most common reasons patients visit their primary care physician. The etiology of sinusitis is multifactorial
in most cases. However, the final common pathway of disruption is usually made with a thorough history. The physical examination
is often unremarkable. Complaints of nasal obstruction, mucopuluent nasal drainage, and facial pain/pressure are most diagnostic
chronic sinusitis. Isolated headache is an uncommon presenting symptom. Computed tomography scans are the gold standard for
diagnostic imaging. They can be used both for diagnosis and surgical treatment. All chronic sinusitis patients, being considered
for endoscopic sinus surgery, should have failed a trial of maximal medical therapy. This includes a 4–6 wk course of oral
antibiotics, nasal steroids, topical nasal decongestants, and oral prednisone if possible. Patients who fail maximal medical
therapy have persistent symptoms that significantly effect their daily activities, have chronic abnormalities on computet
tomography scan, and are candidates for endoscopic sinus surgery. Appropriate patient selection and preoperative counseling
are key factors in patient satisfaction. Most patients with symptoms that significantly impact their daily activities will
receive marked improvement in symptoms after sinus surgery. Endoscopic sinus surgery has undergone radical changes in the
last 15 yr. Minimally invasive techniques, combined with advances in instrumentation and computers have reduced postoperative
discomfort and improved patient satisfaction. 相似文献
102.
Berriman M Hall N Sheader K Bringaud F Tiwari B Isobe T Bowman S Corton C Clark L Cross GA Hoek M Zanders T Berberof M Borst P Rudenko G 《Molecular and biochemical parasitology》2002,122(2):131-140
Trypanosoma brucei evades the immune system by switching between Variant Surface Glycoprotein (VSG) genes. The active VSG gene is transcribed in one of approximately 20 telomeric expression sites (ESs). It has been postulated that ES polymorphism plays a role in host adaptation. To gain more insight into ES architecture, we have determined the complete sequence of Bacterial Artificial Chromosomes (BACs) containing DNA from three ESs and their flanking regions. There was variation in the order and number of ES-associated genes (ESAGs). ESAGs 6 and 7, encoding transferrin receptor subunits, are the only ESAGs with functional copies in every ES that has been sequenced until now. A BAC clone containing the VO2 ES sequences comprised approximately half of a 330 kb 'intermediate' chromosome. The extensive similarity between this intermediate chromosome and the left telomere of T. brucei 927 chromosome I, suggests that this previously uncharacterised intermediate size class of chromosomes could have arisen from breakage of megabase chromosomes. Unexpected conservation of sequences, including pseudogenes, indicates that the multiple ESs could have arisen through a relatively recent amplification of a single ES. 相似文献
103.
The thymic repertoire of neuroendocrine 'self' antigens has been previously described on the basis of the intrathymic expression of neurohypophysial (NHP)- and tachykinin-related peptide signals and receptors. According to that model, the cryptocrine signalling between thymic epithelial/nurse cells and thymocytes through NHP-related signals and receptors constitutes one accessory pathway in the process of T-cell differentiation and/or activation. A pharmacological manipulation of that novel type of cell-to-cell signalling was tested by the investigation of the immunomodulatory properties of novel cyclic hexapeptide oxytocin (OT) antagonists (MSD Research Laboratories). These compounds were found to significantly inhibit the productions of cytokines (mainly IL-1 beta and IL-6) elicited by anti-CD3 treatment of human whole blood cell cultures. Cytokine productions were more significantly reduced by OT antagonists in whole blood cell cultures derived from female volunteers than in those obtained from male donors, suggesting an influence of the gonadal steroid environment on the expression of NHP peptide receptors by immune cells. These observations support the concept of novel immunomodulating approaches through immune-specific neuropeptide antagonists, as well as the pharmacological value of such strategies in selective immunotherapy. 相似文献
104.
Marie D Sauro Randall S Jorgensen Craig K Ewart Jennifer L Schum Paul Gelling 《International journal of psychophysiology》2005,56(1):55-64
Although cardiovascular disease (CVD) remains the leading cause of mortality in women, few studies have examined the role of psychosocial factors in its development. This study examined the moderating effects of sociotropic cognition (SC), a need for social acceptance and approval, on psychosocial stress-induced cardiovascular responsiveness (CVR) and affect reactivity in women. Sixty-eight normotensive, college-aged females were randomly assigned to a low or high social threat condition. Measures of systolic, diastolic and mean arterial blood pressures (SBP, DBP and MAP, respectively), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR) and negative affect were collected during rest, and under conditions of high vs. low interpersonal threat. A two-step hierarchical regression analysis was performed to predict all response variables (BPs, HR, CO, TPR and affect). Increases in SBP, DBP, MAP, TPR and negative affect were greater in the high threat than low threat condition. Changes in SBP, MAP and TPR positively covaried with SC under conditions of high interpersonal threat, but showed no significant covariation in the low threat condition. The data suggest that an excessive need for social acceptance may contribute to rises in BP through an increase in TPR, but not CO under conditions of high social threat. 相似文献
105.
Characterization of Group B Streptococcal Invasion of Human Chorion and Amnion Epithelial Cells In Vitro 总被引:6,自引:2,他引:6 下载免费PDF全文
Scott B. Winram Mechthild Jonas Emil Chi Craig E. Rubens 《Infection and immunity》1998,66(10):4932-4941
Group B streptococci (GBS) have been cultured from the chorioamnionic membrane of pregnant women, usually in association with chorioamnionitis and premature labor (K. A. Boggess, D. H. Watts, S. L. Hillier, M. A. Krohn, T. J. Benedetti, and D. A. Eschenbach, Obstet. Gynecol. 87:779–784, 1996). Colonization and infection of placental membranes can be a prelude to neonatal GBS infections even in the presence of intact membranes (R. L. Naeye and E. C. Peters, Pediatrics 61:171–177, 1978), suggesting that GBS cause chorioamnionitis or establish amniotic fluid infections by partial or complete penetration of the placental membranes. We have isolated and grown cultures of primary chorion and amnion cells from human cesarean-section placentas. This has provided a biologically relevant model for investigating GBS adherence to and invasion of the two epithelial barriers of the placental membrane. GBS adhered to chorion cell monolayers to a high degree. Pretreatment of GBS with trypsin reduced adherence up to 10-fold, which suggested that the bacterial ligand(s) was a protein. GBS invaded chorion cells at a high rate in vitro, and invasion was dependent on cellular actin polymerization. GBS could be seen within intracellular vacuoles of chorion cells by transmission electron microscopy. We also demonstrated that GBS were capable of transcytosing through intact chorion cell monolayers without disruption of intracellular junctions. GBS also adhered to amnion cells; in contrast, however, these bacteria failed to invade amnion cells under a variety of assay conditions. GBS interactions with the chorion epithelial cell layer shown here correlate well with epidemiological and pathological studies of GBS chorioamnionitis. Our data also suggest that the amnion cell layer may provide an effective barrier against infection of the amniotic fluid. 相似文献
106.
107.
Kyle Johnson Brian R. Lane Alon Z. Weizer Lindsey A. Herrel Craig G. Rogers Ji Qi Anna M. Johnson Brian D. Seifman Richard C. Sarle 《Urologic oncology》2021,39(4):239.e9-239.e16
ObjectivesTo examine length of stay (LOS) and readmission rates for all minimally-invasive partial nephrectomy (MIPN) and MI radical nephrectomy (MIRN) performed for localized renal masses ≤7 cm in size (cT1RM) within 12 Michigan urology practices. Both RN and PN are commonly performed in treating cT1RM. Although technically more complex and associated with higher complication rates, Centers for Medicare & Medicaid Services considers MIPN an outpatient procedure and MIRN is inpatient.MethodsWe collected data for renal surgeries for cT1RM at MUSIC-KIDNEY practices between May 2017–February 2020. Data abstractors recorded clinical, radiographic, pathologic, surgical, and short-term follow-up data into the registry for cT1RM patients.ResultsWithin MUSIC-KIDNEY, 807 patients underwent MI renal surgery at 12 practices. Median LOS for cT1RM patients after MIPN (n = 531, 66%) was 2 days and after MIRN (n = 276, 34%) was also 2 days. Among patients undergoing laparoscopic or robotic PN, 171 (32%), 230 (43%), and 130 (24%) stayed ≤1, 2, ≥3 days. Among patients undergoing laparoscopic or robotic RN, 81 (29%), 112 (41%), and 83 (30%) stayed ≤1, 2, ≥3 days. No significant difference was observed between MIPN and MIRN on LOS commensurate with outpatient surgery (≤1-day, OR = 0.97, P = 0.87).ConclusionsLess than one-third of patients had a LOS ≤1-day and LOS was comparable for MIPN and MIRN. Centers for Medicare & Medicaid Services should be advised that MIPN is a more complex surgery than MIRN, most patients receiving a MIPN will require a ≥2-day hospital stay and it would be more appropriate to classify MIPN an inpatient procedure with MIRN. 相似文献
108.
Craig C. Akoh Jie Chen Rishin Kadakia Young Uk Park Hyongnyun Kim Samuel B. Adams 《Foot and Ankle Surgery》2021,27(4):381-388
BackgroundThe prevalence of osteoarthritis of the hallux metatarsophalangeal joint (MTPJ) is 1 in 40 people over the age of 50. Surgical treatment options for MTPJ arthritis include joint preservation, joint resurfacing, and arthrodesis. Hallux MTPJ implants have evolved over the past several decades, but are associated with various complications. The aim of this study was to examine the MAUDE database to determine reported adverse events for hallux MTPJ implants.Materials and methodsThe US Food and Drug Administration’s (FDA) Manufacturer and User Facility Device Experience (MAUDE) database was reviewed from 2010 to 2018 to review voluntary reported adverse event reports for approved implants within the United States. We recorded the type of adverse event and excluded duplicate reports and those extracted from already published literature.ResultsAmong 64 reported hallux MTPJ implant adverse events, the most common modes of adverse events were component loosening (34%), infection (14.1%), component fracture (9.4%), inflammation (9.4%), and allergic reaction (7.8%). Regarding implant type, Cartiva SCI had the highest percentage of adverse events (23.4%), followed by Arthrosurface ToeMotion (20.3%), Ascension MGT (12.5%), Arthrosurface HemiCAP® (10.9%), Futura primus (9.4%), and Osteomed Reflexion (6.3%). There was an increase in reported adverse events after 2016. The MAUDE database does not report the total incidence of implant insertion.ConclusionOur study of the MAUDE database demonstrated that component loosening and infection are the most common modes of adverse events for hallux MTPJ implants. Cartiva accounted for one-fourth of the implant-related adverse events during our study period, followed by ToeMotion, and Ascension MGT implants. Continued reporting of adverse events will improve our understanding on short and long-term complications of various hallux MTPJ implants.Level of evidenceLevel IV; Case Series from Large Database Analysis; Treatment Study. 相似文献
109.
110.