全文获取类型
收费全文 | 8817篇 |
免费 | 368篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 142篇 |
儿科学 | 203篇 |
妇产科学 | 181篇 |
基础医学 | 1369篇 |
口腔科学 | 198篇 |
临床医学 | 899篇 |
内科学 | 1754篇 |
皮肤病学 | 260篇 |
神经病学 | 788篇 |
特种医学 | 446篇 |
外国民族医学 | 3篇 |
外科学 | 1244篇 |
综合类 | 72篇 |
一般理论 | 3篇 |
预防医学 | 376篇 |
眼科学 | 252篇 |
药学 | 653篇 |
中国医学 | 21篇 |
肿瘤学 | 355篇 |
出版年
2022年 | 61篇 |
2021年 | 98篇 |
2020年 | 96篇 |
2019年 | 113篇 |
2018年 | 152篇 |
2017年 | 117篇 |
2016年 | 161篇 |
2015年 | 196篇 |
2014年 | 228篇 |
2013年 | 302篇 |
2012年 | 407篇 |
2011年 | 434篇 |
2010年 | 282篇 |
2009年 | 291篇 |
2008年 | 422篇 |
2007年 | 469篇 |
2006年 | 429篇 |
2005年 | 412篇 |
2004年 | 394篇 |
2003年 | 419篇 |
2002年 | 390篇 |
2001年 | 159篇 |
2000年 | 127篇 |
1999年 | 116篇 |
1998年 | 73篇 |
1997年 | 87篇 |
1996年 | 68篇 |
1995年 | 76篇 |
1994年 | 70篇 |
1993年 | 65篇 |
1992年 | 88篇 |
1991年 | 80篇 |
1990年 | 61篇 |
1989年 | 59篇 |
1988年 | 68篇 |
1987年 | 68篇 |
1986年 | 60篇 |
1985年 | 41篇 |
1984年 | 58篇 |
1983年 | 66篇 |
1982年 | 43篇 |
1981年 | 40篇 |
1940年 | 43篇 |
1937年 | 39篇 |
1933年 | 55篇 |
1932年 | 45篇 |
1931年 | 47篇 |
1928年 | 40篇 |
1927年 | 45篇 |
1926年 | 56篇 |
排序方式: 共有9219条查询结果,搜索用时 15 毫秒
81.
Twenty-five healthy infants were followed from the newborn period to the age of eighteen months, by evaluation of their neuromotor performance. Evaluation of the specific postural reaction patterns (as described by Vojta) did not seem to be any use as a "short-cut" for the early diagnosis of neuromotor abnormalities, a considerable number of deviations from the normal/optimal pattern being noted even in completely normal infants. 相似文献
82.
Eugen Van Der Zypen Franz Fankhauser Ernst F. Lüscher Sylwia Kwansniewska Ceri England 《Documenta ophthalmologica. Advances in ophthalmology》1992,79(3):221-239
Haemostasis was effected in vessels of melanin-rich (MR: choroid) and melanin-free (MF: mesentery) rabbit tissue irradiated with a cw-Nd: YAG laser. The following parameters were employed: - pulse duration: 200 ms (MR) and 100ms (MF); focal spot diameter: 200 m (MR) and 80 m (MF); pulse energies: 100–250 mJ (MR) and 0.5-1J (MF); irradiances: 1.6–4.0kWcm–2 (MR) and 1–2 × 102kWcm2 (MF). In melanin-rich tissue, laser energy is absorbed principally by melanin granules contained within the stromal melanocytes. The heat generated in these structures radiates into the surrounding tissue where it is dissipated. The damage thus incurred by the endothelium of blood vessels encompassed within this field triggers the haemostatic mechanism whereby blood flow is arrested. This effect is realized by the formation of an occluding plug of platelets, which is stabilized by the deposition of fibrin, particularly in capillaries, and to a lesser degree in larger vessels of the vascular lamina. In melanin-free tissue, haemoglobin serves as the primary site of energy absorption, which is thus shifted from the stroma to the vessel lumen. Irradiation of vessels in such tissue leads to thermocoagulation of plasma proteins and consequent stasis of blood flow. 相似文献
83.
Johannes Pill Alfred Völkl Franz Hartig H. Dariush Fahimi 《Archives of toxicology》1992,66(5):327-333
The effects of bezafibrate administered at 10 and 50 mg/kg/day for 7 days to male Sprague-Dawley (SD) and Lewis rats were investigated in order to determine the interrelation between the changes in serum and hepatic lipid contents and activities of selected peroxisomal, microsomal and mitochondrial enzymes in the two rat strains. In both strains, bezafibrate effectively reduced serum and hepatic lipids, increased the liver weight, induced a proliferation of peroxisomes, and selectively elevated the activities of carnitine acetyltransferase and of the enzymes of the peroxisomal -oxidation system. Moreover, immunoblotting revealed that the drug specifically enhanced the concentration of only those peroxisomal enzymes involved in fatty acid -oxidation. The data obtained demonstrate that although the responses initiated by bezafibrate are qualitatively similar in both strains, they differ in their magnitude in a dose-dependent manner, with the Lewis strain exhibiting a more pronounced response than the SD rats. These results show that dose-dependent strain differences as well as the generally known species differences should be taken into account in pharmacological and toxicological evaluations of fibrates in rodents. Furthermore, generalization and extrapolation from rodent studies should be treated with great caution. 相似文献
84.
85.
86.
Gill Sarjeet S.; Wie Siong I.; Guenthner Thomas M.; Oesch Franz; Hammock Bruce D. 《Carcinogenesis》1982,3(11):1307-1310
A rapid and sensitive indirect enzyme-linked immunosorbent assay(ELISA) was developed for micrsomal epoxide hydrolase of ratliver. The assay, which is easily and readily performed, issignificantly more sensitive than most enzymatic epoxide hydrolaseassays routinely used and electroimmunoassays previously developed.The limit of sensitivity of the ELISA is between 25 ngof microsomal epoxide hydrolase. Using the ELISA microsomalepoxide hydrolases of mouse and rat liver were shown to be antigenicallyvery similar, while microsomal epoxide hydrolases of guineapig, monkey and human liver are antigenically distinct fromthose of rat and mouse. The ELISA developed here is capableof detecting microsomal epoxide hydrolase of rat and mouse livereven when significant enzymatic activity is lost. These resultsindicate that the antigenic sites recognized by the antibodiesused are distinct from the catalytic site of the epoxide hydrolase.Approximately 1.9% of rat microsomal protein was quantifiedas microsomal epoxide hydrolase by the ELISA. Low levels ofmicrosomal epoxide hydrolase were also detected in rat livercytosol (0.02% of the cytosolic protein) demonstrating thatmicrosomal epoxide hydrolase is not totally membrane bound orthat an immunologically related protein occurs in the cytosolof normal rat liver. The ELISA developed here will be valuablein investigating further the role of microsomal epoxide hydrolase. 相似文献
87.
Medullary Carcinoma of the Thyroid Gland 总被引:2,自引:0,他引:2
Medullary thyroid carcinoma (MTC) is an uncommon thyroid tumor that has attracted a great deal of interest because of its
frequent presentation as a familial tumor and its primary involvement in the type II multiple endocrine neoplasia (MEN) syndromes
MEN-IIA and MEN-IIB and familial medullary thyroid carcinoma (FMTC). The MTC tumor cells secrete the polypeptide hormone calcitonin,
which serves as an excellent tumor marker, useful for defining the presence of disease, preoperatively or following thyroidectomy.
The discovery that mutations in the RET proto-oncogene are associated with MEN-II syndromes was highly significant in that it demonstrated a clear correlation between
genotype and phenotype; and most importantly it provided a mechanism whereby family members at risk could be identified by
direct DNA analysis. Virtually all patients with MEN-IIA, MEN-IIB, and FMTC develop MTC; therefore there is a clear rationale
for performing thyroidectomy as soon as a RET mutation has been identified. Because MTC appears to be much more aggressive in patients with MEN-IIB, thyroidectomy is performed
during the first year of life in this setting, whereas in patients with MEN-IIA, where the tumor appears to be more indolent,
the procedure can be safety delayed until age 5 years. Reoperative neck exploration in patients with evidence of persistent
or recurrent MTC has been effective in a significant number of patients, although the success of the operation requires careful
patient selection and preoperative assessment. MTC, as expressed in the MEN-II syndromes, is an excellent model to evaluate
the usefulness of interventional therapy in patients demonstrated to have a genetic predisposition for cancer. 相似文献
88.
Smith PD Kuhn MA Franz MG Wachtel TL Wright TE Robson MC 《The Journal of surgical research》2000,92(1):11-17
BACKGROUND: The time required for incisional healing accounts for the majority of postoperative pain and convalescence. Impaired healing prolongs the process further. If a method for accelerating acute incisional wound healing could be developed, patients would benefit from decreased wound failure and an earlier return to their premorbid condition. MATERIALS AND METHODS: In a rat dermal model, cytokine or vehicle infiltration prior to incision was performed using a single dose or four daily doses preincision. Planned incision sites were primed with the proinflammatory cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) or platelet-derived growth factor BB (PDGF-BB) in an effort to activate the inflammatory phase of healing prior to wounding. At the time of incision closure, one half of the incisions were treated with transforming growth factor beta(2) (TGF-beta(2)). Incisional sites were biopsied and stained with hematoxylin and eosin and immunohistochemistry for inflammatory cells and fibroblast populations and breaking strength was measured. RESULTS: Priming skin with GM-CSF or PDGF-BB mimicked the early inflammatory phase of wound healing. Macrophage staining (EB1) and fibroblast staining (vimentin) were significantly increased prior to incision. Inflammatory priming as well as priming coupled with TGF-beta(2) at the time of the incision closure synergistically improved breaking strength. CONCLUSION: This study demonstrates that sequential therapy consisting of priming of tissue with an inflammatory cytokine followed by application of a proliferative cytokine at the time of incision closure nearly doubles the breaking strength of an acute wound. By manipulating the inflammatory and early proliferative phases of wound healing with tissue growth factors, it may be possible to accelerate acute wound repair and shift the wound healing trajectory to the left. 相似文献
89.
Christoph Seger Harald R?mpp Sonja Sturm Ernst Haslinger Peter C Schmidt Franz Hadacek 《European journal of pharmaceutical sciences》2004,21(4):453-463
Supercritical fluid extracts (carbon dioxide without modifiers) of St. John's Wort (Hypericum perforatum L., Clusiaceae) were analyzed by GC-MS, HPLC-DAD and HPLC-DAD-MS. Besides the dominating phloroglucinols hyperforin (36.5 +/- 1.1%) and adhyperforin (4.6 +/- 0.1%), the extracts mainly contained alkanes (predominantly nonacosane), fatty acids and wax esters. The apolar components tended to accumulate in a waxy phase resting a top of the hyperforin-enriched phase. No components of higher polarity like naphthodianthrones were found. A set of hyperforin oxidation products was detected and tentatively assigned using HPLC-MS. 相似文献