全文获取类型
收费全文 | 23586篇 |
免费 | 1845篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 394篇 |
儿科学 | 813篇 |
妇产科学 | 374篇 |
基础医学 | 2424篇 |
口腔科学 | 525篇 |
临床医学 | 2152篇 |
内科学 | 5203篇 |
皮肤病学 | 547篇 |
神经病学 | 1275篇 |
特种医学 | 1101篇 |
外国民族医学 | 1篇 |
外科学 | 4543篇 |
综合类 | 328篇 |
一般理论 | 15篇 |
预防医学 | 1156篇 |
眼科学 | 820篇 |
药学 | 2037篇 |
中国医学 | 38篇 |
肿瘤学 | 1762篇 |
出版年
2023年 | 223篇 |
2022年 | 400篇 |
2021年 | 985篇 |
2020年 | 473篇 |
2019年 | 814篇 |
2018年 | 943篇 |
2017年 | 610篇 |
2016年 | 645篇 |
2015年 | 671篇 |
2014年 | 1014篇 |
2013年 | 1180篇 |
2012年 | 1740篇 |
2011年 | 1709篇 |
2010年 | 866篇 |
2009年 | 814篇 |
2008年 | 1276篇 |
2007年 | 1208篇 |
2006年 | 1124篇 |
2005年 | 976篇 |
2004年 | 879篇 |
2003年 | 748篇 |
2002年 | 645篇 |
2001年 | 587篇 |
2000年 | 551篇 |
1999年 | 489篇 |
1998年 | 162篇 |
1997年 | 136篇 |
1996年 | 138篇 |
1995年 | 143篇 |
1994年 | 114篇 |
1993年 | 97篇 |
1992年 | 267篇 |
1991年 | 284篇 |
1990年 | 248篇 |
1989年 | 212篇 |
1988年 | 208篇 |
1987年 | 219篇 |
1986年 | 192篇 |
1985年 | 177篇 |
1984年 | 111篇 |
1983年 | 126篇 |
1982年 | 85篇 |
1981年 | 70篇 |
1979年 | 129篇 |
1978年 | 77篇 |
1977年 | 69篇 |
1975年 | 58篇 |
1974年 | 65篇 |
1973年 | 88篇 |
1970年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Starling III John BA Patel Purvisha J. MD Rasberry Ron D. MD 《Dermatologic surgery》2005,31(4):484-485
BACKGROUND: Simple surgical excision is one of the most common treatment methods in the dermatologist's armamentarium. We describe a precise postsurgical dressing technique that can be used for wound care of those patients whose treatment involves removal of lesions via cutaneous surgery. OBJECTIVE: To devise a novel, precise, and effective dressing technique for postsurgical wound care. MATERIALS AND METHODS: We describe the technique using common in-office instruments. RESULTS AND CONCLUSION: Wound dressings for lesions located on curved areas such as the ears, nose, cheeks, and chin often exhibit less than adequate adherence and stability. The kerf-cut dressing technique optimizes pliability of dressing tape, and this maximizes efficient and stable application of postsurgical wound dressings to curved areas of the body. 相似文献
22.
Using fura-2 loaded neural tumour cells, SK-N-SH, we demonstrate that receptor-mediated activation of phosphoinositide hydrolysis not only causes the release of Ca2+ from intracellular stores but also causes a concomitant influx of extracellular Ca2+. Thapsigargin (TG), a sesquiterpene lactone, causes a sustained elevation of intracellular Ca2+ and depletion of the inositol 1, 4, 5-trisphosphate-sensitive intracellular Ca2+ stores. In the absence of extracellular Ca2+, the increase in intracellular Ca2+ concentration ([Ca2+]i) was transient, suggesting that thapsigargin activates both intracellular mobilization and the influx of Ca2+ from extracellular space. These results are consistent with the proposal that the depletion of the inositol 1, 4, 5-trisphosphate-sensitive intracellular Ca2+ pool serves as a signal for Ca2+ influx. 相似文献
23.
Brain metastasis is the most common intracranial malignancy in adults. Improvements in modern imaging techniques are detecting previously occult brain metastases, and more effective therapies are extending the survival of patients with invasive cancer who have historically died from extracranial disease before developing brain metastasis. This combination of factors along with increased life expectancy has led to the increased diagnosis of brain metastases. Conventional treatment has been whole brain radiotherapy, which can improve symptoms, but potentially results in neurocognitive deficits. Several strategies to improve the therapeutic ratio are currently under investigation to either enhance the radiation effect, thereby preventing tumor recurrence or progression as well as reducing collateral treatment-related brain injury. In this review article, we discuss new directions in the management of brain metastases, including the role of chemical modifiers, novel systemic agents, and the management and prevention of neurocognitive deficits. 相似文献
24.
25.
Phospho-akt expression is associated with a favorable outcome in non-small cell lung cancer. 总被引:3,自引:0,他引:3
Amit Shah William A Swain Donna Richardson John Edwards Duncan J Stewart Catherine M Richardson Daniel E B Swinson Dipika Patel J Louise Jones Kenneth J O'Byrne 《Clinical cancer research》2005,11(8):2930-2936
Akt, a Serine/Threonine protein kinase, mediates growth factor-associated cell survival. Constitutive activation of Akt (phosphorylated Akt, P-Akt) has been observed in several human cancers, including lung cancer and may be associated with poor prognosis and chemotherapy and radiotherapy resistance. The clinical relevance of P-Akt in non-small cell lung cancer (NSCLC) is not well described. In the present study, we examined 82 surgically resected snap-frozen and paraffin-embedded stage I to IIIA NSCLC samples for P-Akt and Akt by Western blotting and for P-Akt by immunohistochemistry. P-Akt protein levels above the median, measured using reproducible semiquantitative band densitometry, correlated with a favorable outcome (P = 0.007). Multivariate analysis identified P-Akt as a significant independent favorable prognostic factor (P = 0.004). Although associated with a favorable prognosis, high P-Akt levels correlated with high tumor grade (P = 0.02). Adenocarcinomas were associated with low P-Akt levels (P = 0.039). Akt was not associated with either outcome or clinicopathologic variables.Cytoplasmic (CP-Akt) and nuclear (NP-Akt) P-Akt tumor cell staining was detected in 96% and 42% of cases, respectively. Both CP-Akt and NP-Akt correlated with well-differentiated tumors (P = 0.008 and 0.017, respectively). NP-Akt also correlated with nodal metastases (P = 0.022) and squamous histology (P = 0.037).These results suggest P-Akt expression is a favorable prognostic factor in NSCLC. Immunolocalization of P-Akt, however, may be relevant as NP-Akt was associated with nodal metastases, a known poor prognostic feature in this disease. P-Akt may be a potential novel therapeutic target for the management of NSCLC. 相似文献
26.
Alan T. Villavicencio MD Lloyd A. Hey MD Dhavalkumar Patel MD PhD Peter Bressler MD 《The Journal of allergy and clinical immunology》1997,100(6):853-854
J Allergy Clin Immunol 1997;100:853-4. 相似文献
27.
J Rothrock M Patel P Lyden C Jackson 《Cephalalgia : an international journal of headache》1996,16(1):44-49
We compared data from 243 patients with episodic migraine (EM) and 132 patients with chronic daily headache (CDH). We divided the matter group into those with tension-type headache only (CDH Type 1) and those with headaches having migrainous features (CDH Types 2+3) and compared each with the EM group and all three groups with one another. CDH Type l patients differed from those in the other groups by virtue of gender (more often male) and mean age at headache onset (older). The CDH Types 2+3 and EM groups differed only in that the former were more likely to have undergone a brain-imaging study. These data suggest that CDH Type 1 may represent a distinct headache syndrome, while CDH Types 2+3 closely resemble episodic migraine. 相似文献
28.
29.
Partial tolerance in rat renal allograft recipients following multiple blood transfusions and concomitant cyclosporine 总被引:1,自引:0,他引:1
C W Hewitt K S Black J C Harman K R Beko H S Lee A P Patel D C Martin 《Transplantation》1990,49(1):194-198
Multiple prior administrations of donor-strain blood while under limited cyclosporine cover, consistently induce extensive rat renal allograft survival and transplantation tolerance. Yet it was hypothesized that some chronic rejection mechanisms were nevertheless operative since consistent but nonprogressive minor renal dysfunction was observed long-term. A histopathologic study on these putative tolerant rats was undertaken to test this hypothesis. Twenty long-term LEW recipients of BN renal allografts receiving the blood-CsA regimen were examined histopathologically at day 100 post-transplant. Sixteen control LEW recipients receiving only a BN renal allograft were studied acutely at day 7 posttransplant. The control recipients demonstrated a range of lesions consistent with previous studies on acute renal allograft rejection in the rat. However, tolerant recipients demonstrated mild-to-moderate lesions consistent with chronic mechanisms of rejection including the following: moderate focal interstitial mononuclear inflammatory cellular infiltration, with periglomerular and perivascular accumulation; occasional arteriolar luminal obliteration and glomerular atrophy; focal areas of moderate interstitial fibrosis; mild interstitial hemorrhage; mild-to-moderate tubular atrophy; and focal tubular necrosis. Previously our laboratory has documented that tissue-specific renal basement membrane antigens may be responsible for inciting this pattern of focal chronic interstitial inflammation. However, from the present histopathologic studies, it would appear likely that chronic rejection mechanisms in these recipients, which were defined as tolerant by immunologic criteria, involve both tissue-specific and MHC determinants. Therefore, induction of transplantation tolerance in these indefinite survivors is partial or incomplete. 相似文献
30.
K J Patel L M Rueda R C Axtell 《Journal of the American Mosquito Control Association》1990,6(1):101-104
Six different types of alginates used to encapsulate Lagenidium giganteum gave similar levels of fungal infection in Culex quinquefasciatus larvae. Initial infection levels when the capsules were immersed in water after 6 days of storage (15 and 25 degrees C) were 100% for all types of alginate and after 42 days of storage was 62-100%, depending on the type of alginate. Infectivity was 24-100% after the encapsulated fungus were left in water for 7 days and after 15 days was 0 to 26%, depending on the alginate. When 2 of the alginates were tested at different concentrations to give high, medium and low viscosity solutions, the fungus encapsulated using lower concentration alginate solutions usually gave the highest level of infectivity. 相似文献